Obviously it was dirty and dusty, so I've cleaned and restored.
The REX (ZANUSSI) IR023S Refrigerator is really a beast it comes Up to evaporation In the Freezer compartment in 12 sec after compressor start even waiting a 24Hr complete stop and the Freezer compartment it's cooled in a time inferior as 18 mins.
This REX IR023S is a 1985 model fabricated by ZANUSSI under first initial ELECTROLUX period of control because the model was originally designed and fabricated in ZANUSSI Factory in Pordenone ITALY and is slightly different form the after model series with same model codings. Therefore this is a ZANUSSI developed fridge.
It's super silent.
All parts are original, the refrigerator was heavily used and throwed away............in working order.
Compressor ZANUSSI ELECTROLUX (VERDICHTER OE) V1040G R-12 115 WATT.
Many contemporary appliances would not have this level of staying power, many would ware out or require major services within just five years or less and of course, there is that perennial bug bear of planned obsolescence where components our deliberately designed to fail or manufactured with limited edition specificities..............................
REX (ZANUSSI) IR023S REFRIGERATING APPLIANCE WITH SINGLE THERMOSTATIC TEMPERATURE CONTROL DEVICE:
The present invention relates to a refrigerating appliance comprising a refrigerating circuit provided with a thermostatic temperature control arrangement.
Particularly, but not exclusively, the present invention relates to a multi-temperature refrigerating appliance provided with a single thermostatic temperature control device.
Two-temperature refrigerating appliances are well known, having two main compartments which are kept at different temperatures and provided with independent access doors. Usually, one of the compartments is maintained at an average temperature of about + 5 DEG C for preserving fresh goods, whereas the other compartment is maintained at an average temperature of about - 18 DEG C for freezing purposes.
Preferably, such refrigerating appliances utilize one single-compressor refrigerating circuit in which two evaporators associated with relevant storage and freezer compartments are connected in series. An embodiment of this kind is for instance disclosed in EP-A-0 298 349.
The temperature in the refrigerating appliance, determined by alternate operative and inoperative phases of the compressor, is usually controlled by means of a single thermostatic control device which is capable of sensing, directly or indirectly, the temperature of the evaporator associated with the storage compartment.
In order to overcome the above drawbacks it is common practice to provide a so-called "balancing" heating element (consisting of a heating resistance, for example) in the storage compartment, the heating element being controlled by the thermostatic control device to be actuated in place of the compressor during the inoperative phases of the compressor itself.
The amount of heat generated by the balancing resistance during the defrost phases of the storage compartment evaporator artificially compensated for the low ambient temperature, in this way promoting a better ratio between the ON and OFF phases of the compressor, thus enabling the freezer compartment to be refrigerated correctly and causing narrower temperature fluctuations to occur in both compartments.
REX (ZANUSSI-ELECTROLUX) IR023S Temperature control for a cycle defrost refrigerator incorporating a roll-bonded evaporator :
A temperature control system for a refrigerator including a roll-bonded evaporator in the fresh food compartment in which is formed a non-refrigerant carrying passageway extending the full width of the evaporator. A temperature control located in the compartment includes a temperature sensitive capillary tube portion extending substantially the full length of the passageway so as to be subjected to the limited environment of the passageway and accordingly responsive to the true temperature of the evaporator.
1. A cycle defrost household refrigerator including a cabinet having an upper lower temperature food compartment and a lower relatively high temperature food compartment, evaporator means for refrigerating said compartments comprising:
a first evaporator located in said low temperature compartment and a second evaporator arranged substantially vertically in said relatively high temperature compartment and connected to said first evaporator in series refrigerant flow relationship;
means for supplying liquid refrigerant to said liquid carrying conduits in said first and second sections in series and for withdrawing evaporated refrigerant therefrom;
a temperature control means in said high temperature food compartment including a temperature sensitive capillary tube portion having a length corresponding substantially to the width of said second evaporator;
said temperature control being operable by the coldest temperature sensed along the length of said capillary for causing said compressor to cycle off to cause defrosting of said section of said evaporator;
a passageway positioned in heat exchange relationship to said second evaporator extending substantially the entire width between the vertical sides thereof;
said passageway having a cross-sectional dimension for allowing insertion of said capillary tube portion to a position substantially the full length of said passageway and for insuring thermal relationship between said capillary tube portion and said passageway so that said capillary tube portion is subjected to the limited environment of said passageway and the temperature of said second section.
2. The household refrigerator recited in claim 1 wherein said passageway is arranged below the liquid carrying conduits.
3. The household refrigerator recited in claim 2 wherein said passageway is formed to include a central apex from which said passageway extends downwardly and outwardly.
4. The household refrigerator recited in claim 3 wherein there is further provided a drain means located below said passageway for receiving defrost water from said second section of said evaporator.
5. A cycle defrost household refrigerator including a cabinet having an upper low temperature food compartment and a lower relatively high temperature food compartment, evaporator means for refrigerating said compartments comprising: a one piece evaporator formed of a pair of sheets roll-forged together to include liquid carrying conduits between said sheets, said evaporator having a first section located in said low temperature compartment formed in a U-shape to include a back wall portion having substantially horizontally extending upper and lower wall portions and having a second section arranged substantially vertically in said relatively high temperature compartment and connected to said first section by means of a relatively narrow neck portion;
means for supplying liquid refrigerant to said liquid carrying conduits in said first and second sections in series and for withdrawing evaporated refrigerant therefrom;
a temperature control means in said high temperature food compartment including a temperature sensitive capillary tube portion having a length corresponding substantially to the width of said second evaporator.
said temperature control being operable by the coldest temperature sensed along the length of said capillary for causing said compressor to cycle off to cause defrosting of said section of said evaporator.
a passageway formed between the pair of sheets of said second section extending substantially the entire width between the vertical sides thereof;
said passageway having a cross-sectional dimension for allowing insertion of said capillary tube portion to a position substantially the full length of said passageway and insuring thermal relationship between said capillary tube portion and said passageway so that said capillary tube portion is subjected to the limited environment of said passageway and the temperature of said second section.
6. The household refrigerator recited in claim 5 wherein said passageway is arranged below the liquid carrying conduits.
7. The household refrigerator recited in claim 6 wherein said passageway is formed to include a central apex from which said passageway extends downwardly and outwardly.
8. The household refrigerator recited in claim 7 wherein there is further provided a drain means located below said passageway for receiving defrost water from said second section of said evaporator.
The present invention relates to cycle defrost refrigerator wherein defrost of the fresh food compartment evaporator is accomplished during the compressor OFF cycle primarily by convection of the relatively warm above freezing fresh food compartment air and through the heat leakage entering the fresh food compartment and more particularly to a control system for a cycle defrost refrigerator incorporating a roll-bond evaporator.
Generally in a cycle defrost refrigerator the temperature of the fresh food compartment is maintained by sensing the true temperature of the evaporator. This requires that the entire length of the thermostat control capillary tube be maintained in heat exchange relationship with the evaporator. Traditionally many cycle defrost refrigerators suffer from the inability of the control capillary to sense the true fresh food evaporator conditions under critical usage conditions. This often results from the inconsistencies of arranging the control capillary tube relative to the fresh food evaporator so that it will sense accurate evaporator conditions. These control errors often result in residual icing problems, premature compressor trip-offs, and a wide dispersal of operating response characteristics. One common manner of securing the control capillary to the evaporator to insure that the full length of the capillary tube is in contact with the evaporator has been to employ a plurality of clamps spaced along the entire length of the capillary tube. This method requires the use of external parts and labor to secure them to the evaporator and falls short of solving the problem since the relatively small diameter capillary tube realistically cannot conform to the surface of the evaporator.
SUMMARY OF THE INVENTION
An object of the present invention is to provide a passageway which extends across the full width of the roll-bonded plate evaporator and whose cross-sectional area assures introduction of the capillary tube to a position occupying the full length of the passageway so that it is in contact with the walls of the passageway.
By the present invention there is provided in a houshold refrigerator having an upper low temperature food compartment and a lower relatively high temperature food compartment including a one-piece evaporator for refrigerating the compartments. The one piece evaporator is formed of a pair of sheets roll-forged together to include liquid carrying conduits between the sheets. The evaporator has a first section located in the low temperature compartment and a second section arranged substantially vertically in the relatively high temperature compartment and connected to the first section by means of a relatively narrow neck portion. A hermetic compressor supplies liquid refrigerant to the liquid carrying conduits in the evaporator sections in series and for withdrawing evaporated refrigerant therefrom. Located in the high temperature compartment is a temperature control means including a temperature sensitive capillary tube portion. A passageway is formed between the pair of sheets of the second section of the evaporator. The passageway is located below the liquid carrying conduits and extends between the vertical edges of the second section. The passageway has a cross-sectional area which is dimensioned to allow easy insertion of the capillary tube to a position where it occupies substantially the full length of the passageway while at the same time insuring accurate thermal response between the temperature sensitive capillary tube portion and passageway walls so that the capillary tube portion is subjected to the limited environment of the passageway and accordingly the true temperature of the second section of the evaporator.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a sectional view of a two compartment refrigerator incorporating the present invention;
FIG. 2 is a partial front elevational view with the cabinet door removed showing the lower compartment evaporator incorporating the present invention;
FIG. 3 is an enlarged cross-sectional view along line 3--3 of FIG. 2 showing the arrangement of the control tube in conjunction with the illustrated embodiment of the present invention; and
FIG. 4 is a diagramatic showing of the one-piece two-section evaporator incorporated in the embodiment of the present invention.
BRIEF DESCRIPTION OF THE INVENTION
Referring now to the drawing wherein a preferred embodiment of the invention has been shown, reference numeral 10 generally designates a conventional insulated refrigerator cabinet having a below freezing frozen food compartment 12 disposed in the upper part of the cabinet, an above freezing main food storage compartment 14 disposed below the freezer compartment 12, and a machinery compartment 16 arranged in the bottom portion of the cabinet. The frozen food compartment 12 is adapted to be maintained at a temperature low enough to properly preserve frozen food for long periods of time. Thus, the temperature therein is preferably maintained somewhere between -10° F. and 10° F. The main food storage compartment 14 is preferably maintained at temperatures above freezing but low enough to properly refrigerate perishable unfrozen foods. It has been found that temperatures in the range of 37° to 40 20 F. are most satisfactory for this purpose.
The compartments 12 and 14 are refrigerated by a one-piece roll-forged evaporator including evaporators sections 20 and 22 respectively which are connected in series flow in the refrigerant circuit. The refrigerating system used for maintaining the compartments 12 and 14 within the desired temperature ranges mentioned above employs a conventional motor compressor unit 18 which is adapted to be mounted in the machinery compartment 16 and which discharges compressed refrigerant into the condenser 24 positioned across the outside back wall of the refrigerator. Condensed liquid refrigerant from the condenser 24 then flow thru a conventional capillary tube (not shown) to the evaporator section 20 located in the freezer compartment and then to the series connected evaporator section 22 located in the food storage compartment 14.
The evaporators sections 20 and 22 are fabricated from two superimposed planar sheets made in one piece by a roll-forging operation. While the present invention does not reside in a roll-forging method as such, a brief general description of this method is included in order to facilitate a complete understanding of all aspects of the invention. The pair of sheets are superimposed upon one another with a pattern of stop-weld material coated on the one sheet. The stop-weld material provided between the sheets prevents the sheets from adhering to one another throughout the coated area. Following the roll-forging operation fluid under pressure is supplied between the sheets so as to dilate the sheets for the purpose of forming refrigerant passages corresponding to the pattern of the stop-weld material. The stop-weld material is so applied that the internal refrigerant passages extend throughout the major portion of the plate and in effect form two spaced evaporator sections connected in series refrigerant flow relationship. A slot 26 is cut in the composite plate after the roll-forging operation as shown in FIG. 4 so as to separate the evaporator section 20 from evaporator section 22 except at the narrow neck 28.
This narrow neck 28 includes a refrigerant passages 30 (FIGS. 2 & 4), which connects the evaporator section 20 in series with the evaporator section 22. In installing the evaporator sections 20 and 22 in the cabinet the evaporator section 22 may be arranged as shown in FIG. 2 with its vertical side edges 32 adjacent to side walls 34 of the food storage compartment cabinet and substantially parallel to the rear wall of compartment 14 as shown in FIG. 1. The evaporator section 20 as best shown in FIGS. 1 and 4 is folded into a U-shape configuration including a back wall 36 and horizontally extending top and bottom walls 38. It should be noted that other configurations of the freezer compartment evaporator may be used in conjunction with the present invention.
The temperature of the fresh food compartment 14 is regulated by a thermostatically operated temperature control 40 mounted on one side wall 34 in the compartment 14. The control 40 includes a manually adjustable control knob 41 used to select the fresh food compartment temperature and a control capillary tube 42 arranged as will be explained fully to be in contact with the lower portion of the evaporator section 22. The control 40 is used for starting and stopping the motor compressor unit 18 in response to the selected refrigeration requirements. The control 40 is of the type which is adapted to close the circuit to the motor compressor unit 18 when the temperature of the coldest portion of the control capillary 42 is a few degrees above the melting temperature of the frost which may form on the evaporator section 22 during the "ON" cycle of the compressor and is adapted to open the circuit to the compressor when the temperature of the coldest portion of the control capillary 42 approaches the selected evaporator OFF temperature. The relative sizes of the evaporators 20 and 22 and the arrangement of the passages therein are such to provide for automatic defrosting of the evaporator section 22 during the OFF cycle without defrosting the evaporator section 20. It is important to note that the control capillary 42 responds to evaporator temperatures rather than the temperature of the air in the food compartment as it has been found that the temperature of the air in the food storage compartment may be maintained substantially between 37° and 40° F. at all times even though the temperature of the evaporator 22 sensed by the bulb 42 fluctuates over a wide range such as -6° F. to 37° F. The temperature values given herein are primarily for purposes of illustration and may be varied to suit different requirements.
In order for the capillary tube 42 to respond to true evaporator temperature rather than air temperature and to obtain accurate temperature control it must control from the coldest point. In conventional practice this can only be accomplished if the capillary tube is securely and accurately positioned to be in direct contact with the evaporator surface over its full intended sensing contact area or length. To obtain uniform temperature calibrations for a multitude of cabinets of the same type, it is necessary that the same predetermined length of control bulb be arranged in heat exchange relationship with the evaporator wall in each cabinet and that this entire length be in heat relationship with the evaporator.
By the present invention the capillary tube 42 is positioned so as to respond to true evaporator conditions. To this end an open non-refrigerant passageway 50 is formed in the evaporator section 22. The passageway 50 as seen in FIG. 2 is positioned below the lowermost refrigerant pass 52 and the lower edge 54 of the evaporator 22. The passageway 50 extends across the full width of the evaporator and diverges downwardly and outwardly from a central apex 56. The capillary tube 42 is inserted the full length of the passageway 50 as shown by broken lines in FIG. 2 so as to be exposed to temperatures across the full width of the evaporator. For example, the temperature in the inlet area of refrigerant pass 52 might be different than that in outlet area of pass 52.
The length and cross-sectional area of the passageway 50 relative to the diameter and length of capillary tube 42 is such that the capillary tube 42 may be easily inserted therein while at the same time insuring that a thermal relationship is maintained between the capillary and evaporator. The capillary 42 is so positioned in the passageway 50 that it sees only the limited environment generated by the highly conductive walls of the passageway. In the control employed in carrying out the present invention the capillary controls from the coldest point along its length. The arrangement of the capillary and passageway extending across the evaporator insures that Off cycle will be initiated from coldest point along the width of the evaporator which is below freezing and an ON cycle which is initiated from the coldest part of the evaporator which is above the freezing temperature. The passageway 50 as stated above in effect creates an environment in which the capillary tube 40 can sense the true temperature of the evaporator.
By the present arrangement a constant temperature difference between the control capillary and the evaporator is generated which insures a consistent refrigeration cycle initiation and termination with respect to true evaporator conditions such as overall average temperature and frost conditions.
The capillary tube due to its location below the lowest refrigerant carrying pass senses the descending defrost water which impinges on the outer surface of the passageway. The above freezing temperature of the defrost water contacting the passageway 50 influences the temperature of the evaporator and accordingly the temperature sensed by the capillary tube 42. Defrost water impinging on the passageway 50 tends to flow downwardly toward the outer edges 32 and into trough 58 where it flows into a drain tube 60 to be disposed of by evaporation in the machine compartment 16 in any suitable manner (not shown).
While in the embodiment shown a single or one-piece evaporator is shown it should be noted that evaporator sections 20 and 22 may be separately formed and connected by appropriate refrigerant tubing.
Further, the passageway 50 may be formed by brazing or adhesively bonding a tube member to the plate evaporator. A tube so bonded to the evaporator would create the same environment for the capillary tube as formed passageway 50 does in that the capillary would still be in a position to sense true evaporator temperature.
It should be apparent to those skilled in the art that the embodiment described heretofore is considered to be the presently preferred form of this invention. In accordance with the Patent Statues, changes may be made in the disclosed apparatus and the manner in which it is used without actually departing from the true spirit and scope of this invention.
REX (ZANUSSI) IR023S Method for making an improved evaporator.
A method for making an evaporator of the roll-bond type comprises a first step of inserting a return pipe (1) into a passage (3) formed between the two bonded sheets of the roll-bond evaporator (4), a second step of compressing said passage (3) about the terminal portion (8) of said return pipe so as to form a narrow and substantially annular space (12) between said roll-bond passage (3) and a length of said return pipe (1) inserted into said passage, and a subsequent third step consisting of the injection of a semi-fluid substance having sealing and adhesive properties into a further passage (9) obtained by suitably forming the two roll-bonded sheets and having one of its ends provided with a port (11) opening into said space (12), so that and until said substance progressively fills all or part of its volume.
2. A method according to claim 1, characterized in that said port (11) opens into said space (12) substantially adjacent the bottom thereof.
3. A method according to claim 2, characterized in that said sealing substance is of the anaerobic polymerization type.
4. A method according to claim 3, characterized in that subsequent to the filling of said space (12), the corresponding area of the roll bond structure is subjected to a heat treatment, preferably by induction heating, for the polymerization of said sealing substance.
5. A method according to claim 5, characterized in that said induction heating step is carried out for an interval of about 10 to 20 seconds.
6. A method according to any of the preceding claims, characterized in that said return pipe (1) is retained at a fixed position within said passage (3) during the subsequent three steps of the process.
7. A method according to any of the preceding claims, characterized in that the insertion of said return pipe (1) into said passage (3) is carried out so as to avoid any contact between the two components.
8. A method according to claim 7, characterized in that said space (12) has a width of between o.2 and o.5 mm.
9. A refrigerating appliance provided with at least one evaporator, characterized by being made with the employ of the method according to any of the preceding claims.
In refrigerant circuits for domestic refrigerating appliances of a known type, the capillary and the return pipe are connected to the evaporator by means of a "union" using a length of pipe, preferably aluminum pipe, to be inserted into a suitable cavity formed between the two aluminum sheets of which the well-known "roll bond" evaporator is composed.
As generally known, the employ of the roll bond technique permits the manufacture of the refrigerant circuit to be greatly simplified, although there are certain shortcomings known to those skilled in the art and relating to the method employed for making and connecting the evaporator.
As a matter of fact, in known refrigerating appliances equipped with a roll bond evaporator, the return pipe is compression-fitted thereto by exclusively mechanical means. This fitting technique is unable, however, to guarantee hermetic sealing at pressures of more than about 5 kp/cm<2>, so that under certain circumstances the high-pressure fluid tends to leak from the mechanic connection and to thereby escape from the refrigerant circuit.
The gravest inconvenience resulting from this technique is the possibility of the escape of gaseous refrigerant into the ambient atmosphere. This is because the connection of the return pipe to the return passage of the roll bond evaporator as well as the connection of the capillary to the are generally accomplished by the employ of well known procedures consisting in the compression from the outside of determined portions of the roll bond structure about the return pipe and the capillary at the locations of the return passage and the inlet pasage, respectively, of the roll bond evaporator.
This compression-fitting process may be accompanied by soldering the return pipe to the roll bond structure at the point of entrance, or by the application of an adhesive having suitable characteristics to the surface of the capillary and that of the return pipe at the respective compression-fitting locations.
The discussed shortcomings derive from the fact that the soldering operation is always a critical process with sometimes uncertain results, and in any case rather costly. For this reason the soldering method is whereever possible replaced by the application of adhesive at the compression-fitting locations.
On the other hand, however, the application of an adhesive to the surface of the return pipe to be inserted into the roll bond structure is not without problems caused for instance by the formation of bubbles in the thin adhesive coating or by the presence of adhesive-free areas resulting from the viscosity of the adhesive or from the adhesive being scraped off by mutual contact between complementary surfaces during the fitting process, which is usually a manual operation. Finally, the manual application of the adhesive may result in the presence of insufficient or excessive amount of adhesive on different surface areas, giving rise to faulty sealing.
The escape of the gaseous refrigerant cannot always be detected in the course of controls during the manufacturing process, particularly in the case of extremely small leaks. The full impact of the defect is thus noticed only after the refrigerating appliance has been put into use, requiring the manufacturer to carry out extremely onerous and laborious service operations, as well known by those skilled in the trade, without any remedy in sight.
The construction and maintenance of refrigerating appliances of this type are thus rendered rather complicated by the described operations which do not, moreover, lend themselves to being readily automatized.
It would therefore be desirable, and is in fact an object of the present invention, to provide a domestic refrigerating appliance in which the above discussed shortcomings are avoided without incurring construction complications or the necessity of novel technologies, so as to maintain low production costs.
These and other objects are attained in a refrigerating appliance as defined in the appended claims.
The invention will be more fully understood from the following description, given by way of example with reference to the accompanying drawings, wherein: fig. 1 is a diagrammatic illustration of a first step in the method according to the invention for sealingly connecting a return pipe to a roll bond evaporator, fig. 2 shows a second step of said method, and fig. 3 shows a third step of said method.
The method according to the invention is carried out in four distinct steps, the first one of which comprises the insertion of a return pipe 1, with a capillary 2 enclosed therein, into a passage 3 formed between the two sheet layers of a roll bond evaporator 4. The insertion of return pipe 1 into passage 3 has to be carried out in a manner ensuring that the two cylindrical elements are maintained substantially coaxial with one another, or at least with their respective surfaces out of contact with one another.
To this purpose the diameter of return pipe 1 is selected to be slightly smaller than that of passage 3, so that a space 12 of preferably about o.2 to o.5 is defined between the two respective surfaces.
As generally known, return pipe 1 is inserted to a predetermined position 5 of its inner end, while a certain length of capillary 2 projecting from the end of return pipe 1 extends through a restriction 6 formed in a linear extension 7 of return pipe receiving passage 3.
This positioning has to be maintained throughout the three subsequent steps of the operation, but then the operations of inserting the components and fixing them in position can be readily and fully automatised by one skilled in the art.
The second step comprises the compression of passage 3 about an end portion 8 of return pipe 1, and of restriction 6 about capillary 2, and is performed in the conventional manner.
The third step of the process comprises the injection of a semi-fluid substance having sealing and adhesive properties into a further passage 9 obtained by suitably shaping the two sheet layers of the roll bond structure. As clearly shown in the drawings, possage 9 has an outwards opening port 10 at one end, and at the other, a port 11 opening into the narrow space 12 defined between passage 3 of the roll bond structure and the length of return pipe 1 inserted thereinto.
It is important that port 11 opens into the bottom portion of space 12 as shown in the drawings.
The pressure applied for the injection of the semi-fluid substance is effective to ensure that the substance progressively and completely fills space 12 so as to fully replace the air originally contained therein, the length of space 12 having been selected with a view to achieving a reliable sealing effect.
It has thus been found that a length of space 12 of at least 30 mm is sufficient to ensure such reliable sealing effect to guard against gas losses, even when space 12 is not completely filled by the injected substance. Even when the air has not been completely displaced from space 12, leaving a small air pocket adjacent the closed end thereof, the desired sealing of the connection will not be impaired.
As a matter of fact, the hermetic sealing of the connection is substantially brought about by the injected adhesive substance forming an annular diaphragm between, and bonded to, the outer wall surface of return pipe 1 and the inner wall surface of passage 3, this diaphragm being impermeable to the passage of gas from one side thereof to the other.
The formation of an annular diaphragm having the above described sealing properties is ensured by the injection of the sealing substance through the port 11 located, as has been pointed out, closely adjacent the bottom of space 12.
It is preferable to employ a substance of the anaerobic polimerization type and of very low viscosity, and thus capable of penetrating even the smallest gaps of space 12 by capillary action.
Preferred in any case is the employ of a monocomponent anaerobic polymerization substance, for instance TOPFIX NA 84 supplied by CECA company, which requires a certain time for setting at least to a degree permitting the evaporator to be subsequently handled as for mounting it in a refrigerating appliance, without thereby endangering the previously obtained seal.
Since this time interval is usually not available in an automatized manufacturing process with high production rates, it is advisable to provide a fourth step which consists in performing a heat treatment of the area previously supplied with the sealing substance, preferably by subjecting the respective area to induction heating for a very short time, for instance 10 to 20 seconds, by the employ of a technique generally known to those skilled in the art.
At the end of this short period, the return pipe is perfectly sealed to the roll bond structure, so that the evaporator is ready for further processing.
The preceding description has been given on the assumption that the capillary 2 is contained within the return pipe 1. The teaching of the invention still holds valid, however, when the capillary 2 is to be connected to the evaporator independently of the return pipe.
The described method is thus conducive to obtaining the following advantages: a) Rapid establishment of the connection between the return pipe and the evaporator without the need for sealing gaskets or other auxiliary parts, and without the necessity of a soldering step, b) Simplified processing of the roll bond structure, c) Simplification and flexibility of the manufacturing process (to be carried out in separate steps capable of automatization), d) Overall economy of the manufacturing process. e) Above all, the quality of the connection is greatly improved as regards the obtention of a reliable seal, particularly with a view to not readily detectable slow leaks.
It is of course possible to design refrigerating appliances with modifications of what has been described above within the purvieew of the present invention.
REX (ZANUSSI-ELECTROLUX) IR023S DEVICE FOR DRAINING WATER FROM A REFRIGERATING APPARATUS ON DEFROSTING THEREOF:
The invention relates to a device for draining water from a refrigerating apparatus flowing from the evaporator thereof during the defrosting phase. A device of this type essentially comprises a passage extending through a wall of the apparatus and communicating with a collecting receptacle for evaporating of the collected water. In known devices of this type, the passage tends to become obstructed by food particles, dust and the like carried in the drained water, necessitating the passage to be regularly manually cleaned by the user. According to the invention the passage has the approximate configuration of a venturi nozzle, resulting in an air flow passing therethrough in opposite directions as the door of the refrigerating apparatus is opened and closed, whereby the passage is reliably kept free of obstructions.
As generally known the defrosting of the evaporator of a refrigerating apparatus is normally carried out by utilizing the heat produced by suitable electric heater elements disposed in heat-conducting contact with the evaporator, such heater elements being periodically energized and deenergized by thermostatic control means ip response to the terperature sensed thereby.
The water set free by the defrosting operation is usually collected in at least one receptacle disposed below the evaporator and dimensioned in conformity therewith. The collected water is then drained to the exterior of the apparatus through a cylindrical passage having a small cross-sectional area connected to the receptacle and extending through the rear wall of the apparatus.
The passage itself is connected to a further conduit having a larger cross-sectional area and extending vertically along 'the outer surface of the rear wall to terminate adjacent a further collecting receptacle provided in a lower part of the apparatus.
The water contained in the further receptacle is then progressively evaporated by the heat produced by the condenser of the apparatus, the latter being disposed along the outer surface of the rear wall of the apparatus and extending partially into the further receptacle.
In another embodiment the further receptacle is shaped to conform to a top portion of the compressor and disposed in heat-translttlng contact therewith, so that the water contained therein is progressively evaporated by the heat transmitted from the compressor to the receptacle, If in an apparatus of the type described the water collected in the receptacle contained within the refrigerating cell below the evaporator contains any food particles, dust or the like, the described passage and conduit tend to become clogged after some time, so that the water can no longer be drained from the interior of the refrigerating apparatus.
As a result, the water will overflow into the interior of the refrigerating cell, with the resultant annoyance to the user.
To avoid this troublesome occurrence, known refrigerating appliances are supplied with a small hand tool which may be inserted into the bores of the passage and/or conduit for cleaning them of obstructions of the type described above.
In practical use it has been found, however, that satisfactory results are only to be obtained if the user cleans the passage and/or conduit at regular intervals in accordance with the instructions by the manufacturer of the appliance.
The present invention aims at avoiding the occurrence of this trouble yb providing a device for draining the water from a refrigerating apparatus set free by defrosting there of, the main object of the invention being the provision of such a device of simple construction and simple and reliable operation, which is effective to prevent the formation of obstructions of the above described type without requiring any intervention on the user's part as in known appliances of this type.
These and other objects are attained according to the invention in a device for draining water from a refrigerating apparatus on defrosting the evaporator thereof, comprising a water collecting receptacle located below the evaporator and dimensioned in conformity thereto, a duct portion connected to said receptacle and passing at least partially through a respective thermo-insulated wall of the apparatus, and optionally a drain conduit communicating with said duct portion and extending along the outer surface of said wall to terminate adjacent a further water collecting receptacle disposed in a lower portion of the apparatus In accordance with the invention, a device of the type defined above is characterized in that said duct portion is of conical configuration converging towards said wall so as to define a passage of diminishing cross-sectional area,
and in that there is provided at least one profile element adapted to be secured through said wall together with said duct portion, said profile element being formed with a first conical portion adapted to receive said duct portion therein, and a second conical portion converging towards said first conical portion and formed with a projecting lip at a position above said drain conduit.
The specific construction of the device according to the invention ensures that the passages thereof are effectively cleaned of any food particles, dust and the like, without manual intervention by the user, on each opening and closing operation of the door of the refrigerating apparatus by the air flowing through the passage on each such opening and closing operation.
The characteristics and advantages of the invention will become more clearly evident from the following description, given by way of example with reference to the accompanying drawings, wherein: fig. 1 shows a diagrammtical cross-sectional view of a refrigerating apparatus equipped with a draining device according to the invention, and fig. 2 shows an enlarged detail of fig. 1.
A refrigeratign apparatus shown in the drawings is in the form of a domestic refrigerator 3 having a body 4 enclosing a refrigerating cell 5, and a door 6 hinged to the forward portion of body 4 for opening and closing cell 5 from in front of the apparatus.
Disposed in cell 5 is at least one evaporator 7 secured i a conventional manner to a rear wall 8 thereof. Below evaporator 7 rear wall 8 is integrally forked with a water collecting receptacle 9 dimensioned in conformity to evaporator 7.
Receptacle 9 serves the purpose of collecting the water leaking down from evaporator 7 when the latter is defrosted by means of conventional heater elements (not shown), and to direct the collected water to the exterior of the apparatus in a manner to be described.
The lower part of receptacle 9 is integrally formed with a duct portion 10 of conical configuration converging towards the thermo-insulated rear wall 11 of the apparatus (fig. 2).
Duct portion 10 is of a length permitting it to extend partially through rear wall 11, and is formed with a passage 12 of diminishing cross-sectional area.
Inserted between the inner panel 8 and an outer panel 13 of rear wall 11 is a profile element 14 cooperating with duct portion 10.
Profile element 14 has a first conical portion 15 dimensioned for receiving at least part of duct portion 10 therein, and a second conical portion 16 converging towards first conical portion 15 and formed with a projecting lip 17. Planar wall portions 18, 19 and 20 of profile element 14 permit the latter to be positioned in and secured to rear wall 11 of the refrigerating apparatus.
Profile element 14 is mounted in rear wall 11 by first pushing first conical portion 15 onto duct portion 10, followed by engaging wall portions 18 and 19 with outer rear wall panel 13, and wall portion 20 with inner rear wall panel 8 A further conduit 21 is secured in a con ventional manner tc the outer surface of outer rear wall panel 13 at a position below projecting lip 17 of profile element 124.
As shown in fig. 1, conduit 21 terminates at its lower end adjacent a further collecting receptacle 22 mounted on a cover 23 of the compressor 24 of the refrigerating appar-atus and shaped to closely conform to said cover.
Receptacle 22 is thus in heat-transmitting contact with compressor 24, so that the heat emitted by the latter is used for evaporating the water collected in receptacle 22.
Receptacle 22 is preferably provided with a partition 25 for preventing the water from splashing over the rim of the receptacle.
If there is only a very small vertical distance between lip 17 of profile element 14 and receptacle 22, conduit 21 may be eliminated, so that the water flows directly into the receptacle.
On the other hand, receptacle 22 may of course be of different design and located at other positions as in known refrigerating appliances, as long as proper evaporation of the collected water is ensured.
The formation of the restricted passage 12 at the point of convergence of conical portions 15 and 16 of profile element 14 results in the drain passage being effectively cleaned of food particles, dust and the like carried in the water set free by the defrosting operation, so that such water is alway reliably drained into collecting receptacle 22.
This cleaning operation takes place in an automatic manner on each opening and closing operation of door 6 as a result of air flowing through passage 12 in the directions of arrows A and B. respectively.
The water draining device according to the invention is of simple construction and reliable operation, and does not require manual intervention on the user's part for cleaning passage 12, so that the disadvantages and shortcomings of prior art draining devices are effectively eliminated.
Compressor ZANUSSI ELECTROLUX (VERDICHTER OE) V1040G R-12 115 WATT. Compressor with hermetically sealed casing:
An electric compressor, particularly for household refrigerators, comprising an outside casing (1), an inside body (2), a cylinder head (3), a silencer (4) interposed between the cavity inside the compressor casing and the gas inlet pipe within the cylinder head (3), wherein the silencer (4) is substantially L-shaped, the greater side containing the expansion chamber (5) and the lesser side leading to the gas admission port (7) in the inlet valve and then to the outlet pipe (9) toward a Helmholtz resonator, the Helmholtz resonator being formed in the compressor body. The ratio between the area of the admission pipe (6) and the transverse section of the chamber (5) must be approximately 0.03, and the length of the chamber (5) must be approximately 34 mm.
2. The compressor of claim 1, characterized in that the Helmholtz resonator is formed within the compressor body.
3. The compressor of claims 1 or 2, characterized in that the expansion chamber (5) has two substantially parallel plane opposing walls and two curved opposing walls with the same direction and substantially the same angle of curvature.
4. The compressor of the preceding claim, characterized in that the silencer (4) has a constructional shape similar to a hook where the outlet pipe (9) is placed on the end-portion of said hook.
5. The compressor of any of the above claims, characterized in that the silencer (4) performs the function of reducing noise within an adiabatic change.
For better illustration of the present invention it is assumed that the pipe operates in close association with the compressor and that it is made of injection-molded or stamped plastic. This naturally does not limit the invention to this type of material and to this connection.
The fluctuations of gas pressure inside displacement compressors particularly for household refrigerators are of considerable importance in view of their influence on the efficiency and the level of acoustic power emitted by the compressors. Therein the cooling gas coming from the inlet pipe enters inside the airtight housing of the compressor.
The body of the compressor has an inlet pipe inside the casing connected to the inlet valve via various channels and cavities that permit the drawn-in gas to be conveyed inside the cylinder.
This leads to a reduction in the cylinder filling and thus ultimately to a reduction in the cooling capacity of the compressor.
The basic mechanisms regulating the dynamics of the gas movements are as follows.
However, maximizing thermodynamic efficiency in this way would accordingly increase the level of acoustic power emitted, particularly during intake, that is transmitted directly outside the casing of the compressor, thereby compromising the requirements of quietness.
It would therefore be desirable, and is the object of the present invention, to realize a compressor that combines high efficiency with low noise, and is reliable, economical and easy to assemble while using materials and techniques permitted by the state of the art.
This object is achieved with the device described, by way of example and nonrestrictively, with reference to the adjoined figures in which:
- Fig. 1
- shows a view of the inside of the compressor casing with the device shown from the front, comprising a silencer interposed between the intake of the gas from outside of the compressor and the cylinder head;
- Fig. 2
- shows a front inside view of the cover of the silencer;
- Fig. 3
- shows a lateral view of the same detail;
- Fig. 4
- shows a front inside view of the body of the silencer;
- Fig. 5
- shows a lateral section of the same detail.
In order to maintain the process of gas intake within an adiabatic change (thereby preserving the cooling efficiency of the compressor), the acoustic control system is preferably made of plastic material.
An expansion silencer is realized between two pipes (having different sections) and by a Helmholtz resonator whose collar is positioned along the pipe at the outlet of the silencer on the side of the inlet valve.
Inside the silencer the spread of the acoustic waves is subject to interference and reflection phenomena that attenuate their acoustic intensity (understood to be the energy flow per unit of area).
Experiments have shown the transfer function of this component (understood to be the relation between an acoustic signal at the input and an acoustic signal at the output) when the silencer is subjected to an accidental-type acoustic signal, in static states and in air. The silencer has been found to be a low-pass acoustic filter, equipped with two resonances f1 and f2 (see Fig. 6).
The attenuation of the acoustic intensity to resonant frequencies f1 and f2 is obtained by means of the Helmholtz resonator.
It is known that in systems composed of several weakly coupled components (silencer and resonator) the (generally complex) resonant frequencies are divided and shifted along the axis of the frequencies of a known range, so that one frequency is higher and one is lower than the frequency of the unmodified system.
Thus, if a resonator is applied to a cavity (and tuned to have the same natural frequency as an acoustic mode of the cavity), two new coupled modes are produced whose natural frequencies are disposed on the sides of the original frequency. The separation between the frequencies is proportional to the value of the coupling parameter.
To obtain good results with this type of coupling it is necessary to optimize the volume of the resonator in accordance with the volume of the cavity and also the position of the resonator neck, which must be located near a loop of the acoustic mode to be attenuated to a greater extent. It is therefore necessary to apportion these parameters to obtain a reduction of acoustic pressure at the starting frequency, whereby the reduction should be considerable but not excessive so as not to be compensated by a considerable increase of acoustic pressure to the two new frequencies that will be produced.
It is furthermore stressed that there is no flow of gas through the resonator cavity. Since there is thus no variation in the gas temperature due to the interposed cavity, the efficiency characteristics of the thermodynamic cycle are maintained unchanged.
The gas entering the compressor and coming from the inlet pipe is not dispersed in the casing to be then drawn into the inlet pipe present in the compressor body, but is immediately "intercepted" and directed toward the head without being allowed to spread.
For this purpose a silencer is designed and mounted for guiding the path of the gas and connecting on one side the area facing the gas entry port in the casing, and on the other side the inlet port in the cylinder head. The separation which the flow of gas thus undergoes and the particular path that develops achieve the result of preventing the gas from overheating and of blocking the intake noise within the pipe.
Referring to the figures we can see the following components:
The cooling gas in pipe 6 enters chamber 5 inside silencer 4.
The silencer is interposed between the cavity inside the compressor casing and the gas inlet pipe within cylinder head 3, and is substantially L-shaped, whereby the greater side, widened at the center and virtually box-shaped, contains expansion chamber 5 and gas admission pipe 6 into the chamber, and the restriction of the lesser side constitutes gas outlet pipe 8 from chamber 5.
After the restriction the lesser side leads first to gas admission hole 7 in the inlet valve and then to outlet pipe 9 toward a Helmholtz resonator, consisting of a suitable cavity formed within the compressor body.
Expansion chamber 5 can have different forms, but preferably has two substantially parallel plane opposing walls and two curved opposing walls with the same direction and with substantially the same angle of curvature.
Chamber 5 can also have different forms provided that the following proportions are maintained between some critical dimensions.
The ratio between the area of admission pipe 6 and the transverse section of chamber 5 must be approximately 0.03.
Furthermore the length of cavity 5 must be approximately 34 mm.
In order to maintain the process of gas intake within an adiabatic change (thereby preserving the cooling efficiency of the compressor), the silencer is preferably made of plastic material.
It is understood that what has been said and shown with reference to the adjoined drawings is intended only to exemplify the invention, and that numerous variants and modifications may be produced without departing from the present invention as defined in the claims.
The compressor was originally designed by Bosch (Germany)
Verdichter Oe in Fürstenfeld, Austria., the largest producer of refrigeration compressors in the world with an annual production of 21 million compressors in its seven plants located in four continents.
Verdichter Oe History
|1982||Project initiated by the Zanussi Group for a factory near Fürstenfeld, Austria, with the capacity of 1 million compressors per year. The name of the factory, "Verdichter", is the German word for "compressor".|
|1983||Start of production in one shift|
|1984||Start of production in two shifts|
|1986||Change of ownership (Electrolux Group buys Zanussi)|
|1988||Start of production in three shifts|
|1990||Production decrease (Massacre on Tian'anmen Square, less exports to China)|
|1994||Restart of production in three shifts|
|1995||Start of Flexible Shift System (including Saturday morning shift)|
|1996||Start of "Kappa" Project (Development of a new generation of compressors)|
|1998||Start of production 6 days x 24 hours a week|
|1999||Enlargement of factory buildings for Kappa production line|
REX (ZANUSSI-ELECTROLUX) IR023S Method of and apparatus for sealing tubes constructed of metals of high thermal and electrical conductivity:
1. A method of welding together pieces constructed of metals of high thermal and electrical conductivity, wherein a piece to be welded is placed in contact with at least one electrode of negative temperature coefficient, so as to receive the heat energy which is developed therein when it is connected to a source of electricity.
2. A method as claimed in Claim 1, wherein the piece or pieces to be welded together are placed in contact with a pair of electrodes ol' negative temperature coeffici so as to establisll electrical continuity between said electrodes and receive the energy which is developed in these latter as a consequence of the establishment of the electrical continuity.
3. A method as claimed in the preceding Claims, wherein the electrodes are resiliently pressed on to the piece or pieces.
4. A method as claimed in the preceding Claims, wherein the welding is brazing.
5. A method as claimed in the preceding Claims, wherein the welding takes place as a result of plasticising.
6. A method as claimed In Claim 4, which is used for joining together elements of a refrigeration circuit, in particular a capillary tube and a tube of greater diameter.
7. A method as claimed in Claim 6, wherein the tiie tulle oi' greater diameter is previously deformed mechanically to provide a seati ii# i'c,r the capillary tube, and to form a socket region for receiving the brazing material
8. A method as claimed in Claim 4 and in one of the remaining Claims, wherein, at least llnti ] the moment in which the brazing material begins to melt, the intensity of the current circulating through the electrodes is kept at a higher value than during the time in which the electrodes are still maintained in contact witij at least one of the pieces to be joined together.
9. A method as claimed in Claim 8, wherein the intensity of the current circulating through the electrodes is decreased for at least part of the time subsequent to the moment in which the brazing material begins to melt, by connecting at least one resistive component in series with the electrodes.
10. A method as claimed in Claim 5 and one or more of the remaining claims, wllich is used for sealing a tube of a circuit containing a fluid under pressure.
11. A method as claimed in Claim 10, wherein the tube is meelBlically deformed on both sides of the weld before the weld is made.
12. An apparatus for carrying out the method as claimed in the preceding Claims, comprising at least one electrode ol' negative temperature coefficient, and means for connecting it to a source of electricity.
13. An apparatus as claimed in Claim 12, wherein the means izor connecting it to the source of electricity comprise the actual piece or pieces on which the electrode acts.
14. An apparatus as claimed in Claim 12 and/or 13, comprisillg a pair of electrodes of~ negative temperature coefficient which are mobile substantially in the same plane but in opposite directions, and between which the piece or pieces, used as tlie electrical connection means, are gripped
15. An apparatus as claimed in one or more of Claims 12 to 14, comprising a switch for connecting a resistive component I in series with the electrodes.
16. An apparatus as cm aimed in Claim 15, wherein the switch is controlled by a thermostat.
17. An apparatus as claimed in Claim 14, wherein at least one electrode is mounted resiliently yieldable in a mobile operating head wliicl, comprises at least one jaw for deforming the piece, in particular for mechanically closing a tube.
18. An apparatus as claimed in Claim 17, comprising two mobile heads and control means for moving said heads.
This invention relates to a method of welding together pieces constructed of metals, which can be different, but which have high thermal and electrical conductivity.
Although the invention can be applied to many fields, those of particular interest are a) joining a copper tube to an aluminium tube, for example in the refrigeration circuit oi' a domestic refrigerator, and b) sealing the copper tube through which the refrigerant fluid is charged into the refrigeration circuit of a domestic refrigerator.
In case a) , the copper tube can be the capillary tube and alluminium tube the evaporator and/or the suction tube of the compressor in the circuit. The capillary tube is that element of the refrigeration circuit in which the (theoretically isenthalpic) expansion occurs of the liquid refrigerating fluid whicli leaves the condenser to then enter the evaporator. As the undercooling of the capillary tube increases the useful effect of the refrigeration circuit, it is usual to insert a portion of the capillary tube in said suction tube.
It is therefore necessary to make at least one joint at the point in which the capillary tube enters the suction tube. A further joint is usually necessary at the point in wliic the capillary tube enters the evaporator, particularly if this latter is in the form of a tubular coil. As it must be ensured that the refrigeration circuit is absolutely hermetically sealed, the quality of the joints must be excellent, in spite of the difficulties due to tulle fact that the two pieces to be joined together are dii'ferent from each other, and have such a high electrical conductivity that it is impossible to make the joint by conventional resistance welding.
Again with reference to case a), a Jointing system is known which uses a short auxiliary copper tube having an outer diameter intermediate between the diameter of the capillary tube and the diameter of the aluminium tube. The capillary tube passes through said auxiliary tube, and is joined to one end thereof by torch brazing.
The other end of the auxiliary tube is joined to the aluminium tube by further brazing or by pressure welding.
This jointing system is certainly of good quality, but is relatively complicated and above all costly because of the copper construction of said auxiliary tube. The absolute value of this cost is very high when, in a modern industry, daily production amounts to several thousands of refrigerators.
With regard to case b), in the known method the copper charging tube is firstly closed by mechanical deformation using a clamp, and then, with the clamp applied, it is filled from its open end with a brazing material melted by means of a torch. This method has the disadvantage of not completely ensuring the opening of the welding zone, requiring the use of specialised labour and involving the use of a large quantity of brazing material when related to a daily production of several thousands of refrigerators.
The object of the present invention is to provide a new welding method, in particular for joining a copper capillary tube to an aluminium tube, and for closing the end of t}ie charging tube of a refrigeration circuit, in which low cost and simplicity of operation are attained together with excellent weld quality.
According to the method of the invention, a piece to be welded is placed in contact with at least one electrode having a negative temperature coefficient so as to recieve the heat energy developed in it when it is connected to a source of electricity.
In a preferred embodiment of the method ac cordillar to the invention, he piece or pieces to be welded together are placed in contact with a pair of electrodes having a negative temperature coefficient so as to establish electrical continuity between these electrodes and receive the heat energy which is developed in these latter as a consequence of establishing electrical continuity.
The term electrode having a negative temperature coefficient" indicates an electrode, the electrical resistallce of which decreases as the temperature increases.
The heat transmitted by the electrode or electrodes to the piece or pieces melts the welding material in contact with the piece, or at least transforms the piece into its plastic state so that, in this latter case, it is sufficient for the electrodes to exert a low pressure on the piece to form the weld.
The apparatus which enables the method to be carried out and is also part of the invention comprises at least one electrode of negative temperature coefficient, and meals lor connecting it to a source of electricity.
In the preferred embodiment of the apparatus, the mealls for connecting it to tulle source OS' electricity comprise the actual piece or pieces on which the electrode is to act.
In the most advantageous embodinlent of the invention, the apparatus comprises a pair of electrodes of Negative temperature coefficient, which are mobile sub staiitially in the same plane but in opposite directions, and between which are gripped the piece or pieces to be welded, these latter being utilised as the electrical connectioii means.
All the characteristics and advantages of the present invention will be apparent from the description given hereinafter (which, as a non-limiting example of application of this method, relates both to joining a copper capillary tube to an aluminium suction tube of the refrigeration circuit oi a domestic refrigerator by brazil and to sealing the end ol the charging' tube of such a refrigeration circuit) and from the accompanying drawing, in which:
: Figure 1 is a sectional diagrammatic view, through their axes, of two tubes during the operations involved in their joining; Figure 2 is a cross-section through said tubes on the line Il-Il of Figure 1 after the joint has been completed and the electrodes used have been removed; Figure 3 shows the electrical circuit used for melting the brazing material; Figure 4 shows the variations in the current intensity through the suction tube and its temperature adjacent to the electrodes during the joining by brazing; Figure 5 is a side view of the apparatus for welding (sealing) the charging tube of a refrigeration circuit; Figure 6 is a section on the line VI-VI of Figure 5, and Figure 7 shows a portion of the charging tube after its sealing.
With reference to Figures 1 and 2, a copper capillary tube 1 is inserted directly into a portion of an aluminium tube 2, for example representing the tube which constitutes the evaporator of a refrigeration circuit of a domestic refrigerator. There is thus a first great financial advantage in eliminating the aforesaid auxiliary copper tube. The aluminium tube 2 can have an outer diameter of 10 mm (against the 2 mm of the capillary tube 1), and has previously been mechanically deformed over a small portion 3 just after the mouth 4 to provide a flare 5 and a double lobed section at said portion 3 (see Fig. 2).
The brazing material and its de-oxidising agent are placed in the flare 5. These substances are indicated together by the reference numeral 6. The brazing material tried by the applicant in the example of the application of the method described here was the alloy known commercially as "So) dwiiol 1 265" of Messrs. Degussa ( the alloy carries the symbol L-CdZn 20, in accordance with D1N 1707). This is a eutectic cadmium-zinc alloy with Hs.5es of cadmium and a melting point of 266 C. The de-oxidising agent tried was wSoldaflux AL" of Messrs.
Degussa (carrying the symbol F-LW 3, in accordance with DIN 8511), its action being effective over the temperature range of 200 to 300 C.
According to the invention, the high conductivity of the aluminium with which the tube 2 is made is utilised to melt the brazing material. Thus the aforesaid technical and economical drawbacks due to the use of torch brazing are obviated. For this purpose, an electrical circuit (shown diagrammatically in Fig. 3) is constructed comprising the terminals 7 and 8 which receive an alternating single phase current from the secondary winding of a voltage step-down transformer (not shown), supply cables 9 and 10, and a pair of electrodes 11 and 12 of a material such as graphite which has a negative temperature coeffi cient. By the Joule effect, the electrical energy at the electrodes 11 and 12 is transformed into heat which reaches the brazing material by conduction through the tube 2.
These electrodes are brought into contact with the portion 3 of the tube 2 at the beginning of brazing. ln the electrical circuit diagrai ot' Fig. 3, the electrodes are shown as two variable resistor with the said reference numerals 11 and 12, whereas the reference numeral 13 indicates the resistance, obviously of extremely low value, of the tube 2 through which tulle circuit is made.
The circuit also comprises a switch 14 wlich, according to the control signals which it receives from the regulator 15, can be shifted from tulle contact 16 to the contact 17 to connect into the circuit a secondary branch 18 which comprises a high ohmic resist or 19.
The reglll ator 15 can be any device able to cause said resistor 19 to be connected in series with the electrodes 11 and 12 and tube 2 when the brazing material has reached its melting point, so reducing the current intensity l in the electrical circuit. In this respect, the applicant has fouiid that this lives an energy saving because the absorbed power of the circuit call be reduced by as much as 7596 during tlie second brazing stage (i.e.
when the switch 14 is closed on tlie contact 17) with respect to the first stage (i.e. when the switch 14 is closed on the contact 16). Advantageously, said regulator 15 is a rapid response thermostat, the sensor of which determines the temperature of the aluminium tube 2 in the immediate vicinity of the point in which it is joined to the capillary tube 1.
However, the regulator 15 can be in the form of a timer, provided it is known accurately after what time from the beginning of the operation the timer must shift the switch 14 from the contact 16 to the contact 17 (on the basis of all accurate trial run of the brazing operation).
The variation in current intensity I (measured in amperes) passing through the tube 2 during brazing, and the variation in temperature in C of this tube ( which can be sprayed with a conventional coolant after' brazing) shown in Figure 4 have been obtained by tests carried out by the applicant.
After the brazing material has melted, the electrodes 11 aiid 12 are removed from contact with the portion 3 of the tube 2, so that it is possible to remove this latter (now joined to the capillary tube 1) and proceed to a further brazing operation. In Figure 1 the approach and withdrawal of the tube electrodes are shown by arrows.
Fiiially, it silould be noted that in this example the el ectiodes do not exert any mechanical deformation action on the pieces to be joined together ( the tubes 1 and 2 in tills example). Thus(also because of the fact that the material of which the electrodes are made has a Ilegative tell1J#erature coefficient, i.e.
its electrical resistance decreases as its temperature increases) the method described herein is conceptually the opposite of collventional resistaiice welding of ferrous metals, which have a relatively high thermal and electrical conductivity.
The advalltages of the method according to the present invention can be suiirtriarised as follows: pieces made of materials of high electrical and thermal conductivity can be joined together by brazing other than torch brazing, and thus more simple to carry out and of much higher reliability; the energy consumption can be considerably reduced by not supplying excess energy when this is not required; in tlie particular case of joining a capillary tube to an aluniinium tube, it is no longer necessary to use an intermediate auxiliary tube.
With reference to Figures 5 to 7, which show the sealing of the tube for charging the refrigeration circuit of a domestic refrigerator with refrigerant fluid, the tube in question, constructed for example of copper, is indicated by the reference numeral 100. It is welded to the casing 101 which contains the compressor and its electrical drive motor (not shown), and communicates with the casing interior.
In order to introduce the refrigerant fluid, a connector element 102 incorporating a non-return valve 103 is mounted on the free end of tle tube 100 by well known methods. Again by well known methods, a charging pistol is connected to the connector element, and when operated causes pressurised refrigerant fluid to flow into the circuit. After the charging operation, the pistol is disconnected from the connector element, and the circuit then contains pressurised refrigerant fluid which cannot escape because of the non-return valve 103.
The problem solved by the invention is to properky seal the tube 100 after said charging operation, without usi)ig welding material.
According to the inventioll, the problem is solved by causing localised plasticising or fusion of the charging tube, mainly by the lleat given up by electrodes 104, 105 of negative temperature coefficient, for example of graphite, which are moderately pressed from opposing sides against the tube and thus cause permanent sealing of the tube by welding as a result of the plasticising or fus ioll .
Advai)te(J;eousiy, to prevent the pressurised refrigerant fluid iii the circuit from being able to escape through tlle passages wllic}l can open up in the plasticising or fusion zone, the tube is closed before welding and maintained closed during welding, by mechanical deformation exerted in a zone between the electrodes 104, 105 and the casing 101, and optiollally also in a zone between the electrodes and tulle free end of the charging tube.
The said operations are carried out by the device shown in Figures 5 to 7, comprising electrodes 104, 105 and means for localised temporary mechanical closure of the tube.
Tulle device in question comprises a pair of levers 106, 107 rotatable about their pivots 108, 109, and supported at their ends in a pair of parallel fixed side plates 110.
Each lever 106, 107 comprises at one end a working head 111 in which the electrode 104, 105 is disposed, and at the other end a roller 112 which, urged by springs 113, 114, is kept in contact with the end of a rod 115 of a piston 116. This piston is slidably mounted in a cylinder 117, and on one of its ends there acts a return spring 118 and on the other end there acts a pressurised fluid fed for example through a solenoid valve, not shown.
The end part 119 of the rod 115 is conical so that when the pressurised fluid is fed into the cylinder 117, the consequent movement of the piston 116 in the direction of the arrow A causes the levers 106, 107 to rotate in such a direction as to cause the working heads 111 to approach each other.
These heads comprise a fork structure with a pair of anns 12(), 121, the purpose of which is to deform the tube 100 at tlie two sides of the electrodes 104, 105 wheii the rod 115 is moved in the direction of the arrow A.
Each electrode 104, 105 is removably housed in a dovetail cavity 122 provided in a partly slotted metal block 123, with ducts 124 for the passage of cooling water ied through flexible hoses, not shown. Tlie block 123 is provided witlj a shank 125 of polyg'oiiai or square crosssection slidable in a bore of correspolldillg cross-section provided in tlie crosspiece 126 of tlse fork structure. The shank 125 comprises a head 127 against which a compression spring 128 acts,
In the device concerned, the electrical circuit extends from the terminals B and C of an electricity source, through the electrodes 104, 105 and through the tube 100, when this latter is in contact with the electrodes.
The tube and electrodes are therefore in series when the device operates. The circuit is opened when the electrodes 104, 105 withdraw from the tube 100 following the return of the rod 115. Thus the welding operation, which will be discussed in greater detail hereinafter, can be controlled by the operator by operating the valve (e.g. a three-way valve) associated with the cylinder 117.
Operation is as follows: The two heads 111 are initially spaced apart from each other to allow the insertion of the tube 100 to be sealed (welded). When the tube is dosed between the heads, the operator feeds fluid under pressure to the cylinder 117. The rod 115 moves in the direction of the arrow A, the levers 106, 107 rotate about the pivots 108, 109, and the heads 111 approacl# the tube 100. The electrodes 104, 105 firstly touch the tube at the point N, but electricity is not as yet fed to the electrical circuit, even though this is ready to receive it.
The arms 120, 121 tlien act on the tube to deform it and close it mechanically in two zones K and M to tlie sides of the welding point N, this point being where the electrodes act.
The connector element 102 caii not be removed.
Electricity is now fed to the terminals B, C (e.g. by means of a contact) and flows in the circuit which is closed through the electrodes 104, 1()5 and tube 100. The electrodes 104, 105 progressively increase in temperature and thus heat point N to a sufficient extent to transform it into its plastic or partly molten state so that the small pressure wlsich the electrodes exert on the tube (by virtue of the springs 128) is sufficiei,# to produce deformation and corlsequent welding (when the opposing sides of the tube come into contact with each other).
On termination of welding (sealing), the operator unloads the cylinder 117, the two heads 111 withdraw from the tube and as the circuit is broken the electricity no longer traverses the electrodes 104, 105, which therefore cease to heat up.
The apparatus is thus ready for a new working cycle.
The present invention covers any other field of application of the described method, comprising the joining together of more than two pieces and the utilisation of the conductivity of all or some of the metals of which the pieces are constructed, to perform the welding, i.e. the fusion of the brazing materials.
Zanussi was an Italian producer of home appliances that in 1984 was bought by Electrolux . Zanussi is a leading brand for domestic kitchen appliances in Europe. Products have been exported from Italy since 1946.
The Zanussi Company began as the small workshop of Antonio Zanussi in 1916. The enterprising 26-year-old son of a blacksmith in Pordenone in Northeastern Italy began the business by making home stoves and wood-burning ovens.
After his father death in 1946 “Lino Zanussi” became the President of the company.
In the early 1970s Zanussi sold a lot in the UK and for some time after under the “Zoppas” brand, name which had been acquired, making Zanussi the first largest Italian appliance maker. They also produced washing machines Hotpoint for Hotpoint at this time which were very reliable and highly rated by users and engineers.
In the late 1970s and into the early 1980s the company had a range of washing machines which used an induction motor with a clutch pulley system. Again this range proved extremely popular and very reliable.
During this period Zanussi Professional, the catering range of appliances for commercial use, became a separate division in its own right.
In the early 1980s Zanussi launched the Jetsystem washing machine range to great acclaim whilst at the same time running the “Appliance Of Science” advertising campaign which is acknowledged as one of the most successful marketing campaigns of all time, in fact still remembered by many today. This gave the brand the impression of being forward thinking and innovative.
Zanussi has recently been rebranded as Zanussi-Electrolux in line with many other Electrolux brand names. Since that time many Zanussi appliances share common components and parts with the rest of the Electrolux range, primarily Electrolux, Tricity Bendix and AEG although it is worth noting that the “John Lewis” branded machines sold by the John Lewis Partnership in the UK are effectively rebranded Zanussi appliances.
In the late 1980s Zanussi launched the split tank design known as the “Nexus Tub” design which endures to this day with little change. The tub, base and certain other parts are made from a plastic material known as “Carboran” which can be re-used several times if recycled. To this day neither Zanussi or Electrolux has provided any way to return this material for recycling purposes.
Up until the end of the 1980s Zanussi service was run from Slough and was a network of independent repairers who gave an unparalleled service level. It is generally acknowledged within the industry that this service network was the best that there has ever been in the UK.
In the early 1990s Electrolux instigated amalgamating all its UK brands under one service entity. This entity was split, dependent on region, between the Zanussi service agents and the local Electrolux Service Centre. In general those in a high population density area where given to the Electrolux employed centres. Tricity Bendix, Electrolux and AEG as well as Zanussi were all to be serviced by the one network.
This was changed in the late 1990s and early 2000s as Electrolux sold or gave away the regional service centres, generally to the existing management or to area managers to run as independent businesses.
This service network was rebranded and became Service Force which still exists today but is, once again, all operated by independent service companies who repair and supply spare parts for all of the brands.
Stern / REX / Zanussi / Seleco (WAS) is an electronics company based in Pordenone, Friuli Venezia Giulia, Italy. It is part of Super//Fluo, who bought the rights in August, 2006, along with Brionvega and Imperial.
Sèleco was born as in 1965 as a spin-off from the home appliances maker Zanussi. In the first years of his life, Seleco produced almost black and white televisions with the Zanussi or Rex brand. The company was being sold in 1984, and was first acquired by Gian Mario Rossignolo. He first became president and then main stockholder.
During the 1980s, the company launched worldwide marketing campaigns and began sponsoring some of the most famous Italian soccer team, such as Lazio A.S..
During the '90s, the company was mainly concentrated on the production of pay-tv decoders, but in 1993 suffered from a loss of competitivity. With the intent to reshape its position and to get gave new life to the company, Gian Mario Rossignolo bought Brionvega from the Brion family, the founder. This attempt get to nowhere, so the company was forced to declare failure in 1997. During the years, Sèleco has passed through ups and downs, at the end being overcome by the continuous changes in the electronics world.
After the crack-down, the company and all its interests were bought by the Formenti family. That gave life to the Seleco-Formenti Group, owner of the rights for the brands Sèleco, Rex, Phonola, Imperial, Stern, Phoenix, Televideon, Kerion and Webrik.
The Formenti family re-launched the company with the production of CRT-TVs. In 2000, the company suffered of a strong crisis, following the price dumping made by Turkish manufacturers. That seems to led to end of the Sèleco and Brionvega story, as the Sèleco-Formenti Group was forced to liquidation.
In 2004, the rights for the radio branch were bought by Sim2 Multimedia, and all the television interests (for the brands Sèleco, Brionvega and Imperial) were acquired by Super//Fluo in August 2006.
THIS INDUSTRY IS TODAY DEAD !!!!