GB2143014A

GB2143014A - Refrigerator/freezer units

Info

Publication number: GB2143014A
Application number: GB08412060A
Authority: GB
Inventors: Graham Arthur Gostick; David Ward Sowerby
Original assignee: Hotpoint Ltd
Current assignee: Hotpoint Ltd
Priority date: 1983-05-16
Filing date: 1984-05-11
Publication date: 1985-01-30
Also published as: GB8412060D0; GB2143014B

Abstract

A refrigerator/freezer unit having a single compressor (1) feeding refrigerant to two evaporators (2, 3) via capillary tubes (4, 5) passing inside the bore of the suction return pipes (8, 11) normally requires that the copper capillary tubes "break out" of the aluminium suction pipes several times to form the required connections thus using several expensive copper/aluminium joints. In this fridge/freezer unit the capillary tubes (4, 5) are fully enclosed within the suction pipes (8, 11) by using an arrangement whereby the suction pipe (11) from the compressor (1) has a fork, one arm leading to one evaporator (2) and the other arm leading to the other evaporator (3) without the need for any copper/aluminium joints. <IMAGE>

Description

SPECIFICATION Refrigerator/freezer units This invention relates to refrigerator/freezer units of the type having a single compressor for pressurising regrigerant which is fed to two evaporators, one for each of the refrigerator and freezer compartments respectively, and particularly to those types of refrigerator/freezer units in which at least one of the evaporators is designed to be integral with the cabinet structure.

In refrigerator/freezer units of the type described above, the two evaporators are individually fed with refrigerantthrough separate throttling or capillary tubes under the control of a divertervalve. The refrigerant is returned to the compressor by way of suction return pipes coming from each evaporator. It is usual for the evaporators to be connected in series so that the refrigerant coming from one evaporator passes into the inlet to the second evaporator, leaving only the second evaporator suction return pipe connected to the compressor.In order to obtain good heat exchange between the capillary tube and the suction pipe, the capillary tube usually passes inside the bore of the suction pipe, however this means that the capillary tube feeding the first evaporator must "break out" of the second evaporator suction pipe and "break into" the first evaporator suction pipe, which is complicated and costly.

It is an object of the present invention to provide a simpler and more efficient refrigerator/freezer unit overcoming the above disadvantages.

Accordingly, the invention provides a refrigerator/ freezer unit of the type comprising a single com pressorfor pressurising a refrigerant and two evaporators, one for each of the refrigerator and freezer compartments, wherein the unit further comprises capillary tubes forfeeding the refrigerant to the evaporators, and suction return pipes connected to the evaporators to return the refrigerant to an inlet pipe leading to the compressor, wherein said capillary tubes are fully enclosed within the bores of said suction return pipes for substantially their entire length between said compressor inlet pipe and said evaporators.

Preferably, there are two capillary tubes within a single suction return pipe connected to the compressor inlet pipe, which suction pipe has a fork near to orforming part of the inlet to the freezer evaporator so that one capillary tube follows inside one arm of the fork into the freezer evaporator and the second capillary tube follows inside the second arm of the fork which forms the suction pipe leading to the refrigerator evaporator.

The two evaporators may be connected in series such that the flow of refrigerant from the refrigerator evaporator passes to the inlet of the freezer evaporator with only the freezer suction pipe being connected to the compressor inlet pipe. Conveniently, therefore, the refrigerator suction pipe is connected to the inlet of the freezer evaporator and the two arms of the fork are sealed around the respective capillary tubes to ensure that the refrigerant flows into the freezer evaporator, there being a connection from the outlet of the freezer evaporator to the freezer suction pipe on the compressor side of said seals.

One embodiment according to the invention will now be described in more detail with reference to the accompanying drawing which is a schematic diagram of the refrigerant flow pipes between the compressor and the evaporators.

A refrigerator/freezer unit (not shown) comprises a single compressor 1 for pressurising refrigerant and causing it to flow from the low pressure side to the high pressure side of the system, a first evaporator 2 for the refrigerator compartment (not shown) and a second evaporator 3 for the freezer compartment (not shown). The evaporators are of the roll bonded aluminium type and are individually fed with refrigerant through separate capillary tubes 4 and 5.

The flow of refrigerant to each evaporator is controlled by means of a diverter valve 6 which directs the refrigerant flow along one or other capillary tube according to the demands of the temperature control system. The system also includes a condenser 7 and filter dryer 17 between the compressor and the diverter valve.

The two evaporators 2 and 3 are connected in series such that the flow of refrigerant from the evaporator 2 via the refrigerator suction return pipe 8 passes into the inlet 10 of the evaporator 3 via the connection pipe 9. The refrigerant from the refrigerator evaporator 2 thus passes though the freezer evaporator 3 before flowing back to the compressor 1 via the freezer suction return pipe 11.

in order to obtain the best possible heat exchange between the capillary tubes 4 and 5 and the suction pipes 8 and 11, the capillary tubes pass inside the bore of the suction pipes. Thus to route the capillary tube 4 feeding the evaporator 2 from the suction pipe 11 to the suction pipe 8, without the need to "break out of and into" the system, the suction pipe 11 is forked into two parts when it reaches the evaporator 3. One part leads the refrigerator capillary tube 4 towards the evaporator 2 and forms the refrigerator suction pipe 8, and the other part leads the freezer capillary tube 5 into the evaporator 3.

Obviously, in order to achieve the desired flow of refrigerant as described above, the suction pipes must be blocked to prevent the flow of refrigerant at the points 12, 13 and 14 from returning directly to the compressor down suction tubes 8 and 11 and causing it to flow through the evaporators 2, 3.

However, by constricting the diameter of the pipes until they just allow the capillary tubes through, they can be sealed without the necessity for breaking the capillary tubes out of and into the suction pipes.

This is very advantageous, because the suction pipes are made of aluminium and the capillary tubes are made of copper, and such "breaking out of or into" the suction pipes would require a section of copper pipe to be introduced at that point, it not being possible to satisfactorily leave or enter an aluminium pipe with a copper capillary tube. The addition of sections of copper pipes is of course disadvantageous since this requires further aluminium/copper joints.

In the described arrangement, there is only one such joint 15 where the freezer suction pipe 11 joins the compressor inlet pipe 16 which is made of copper, and the capillary tubes "break out" of this once only.

Further, since the forked part of the suction tube forms part of the inlet to evaporator 3, there is a reduction in the number of welds needed, as at 18 for exam pie, compared to conventional units. In the present arrangement there is only one pipe entering and one pipe leaving evaporator 3 and only one pipe entering evaporator 2 so that only three welds are needed in total.

Thus the arrangement according to the invention reduces the number of joints, the number of welds, and the quantity of tubing required, and thus reduces costs. It also achieves improved efficiency by having the capillary tubes fully enclosed within the suction pipes at virtually all points in the system.

Claims

1. A refrigerator/freezer unit of the type comprising a single compressorfor pressurising a refrigerant, and two evaporators, one for ech of the refrigerator and freezer compartments, wherein the unit further comprises capillary tubes for feeding the refrigerant to evaporators, and suction return pipes connected to the evaporators to return the refrigerant to an inlet pipe leading to the compressor, wherein said capillary tubes are fully enclosed within the bores of said suction return pipes for substantially their entire length between said compressor inlet pipe and said evaporators.

2. A unit according to Claim 1 wherein there are two capillary tubes within a single suction return pipe connected to the compressor inlet pipe, which suction pipe has a fork near to or forming part of the inlet to the freezer evaporator so that one capillary tube follows inside one arm of the fork into the freezer evaporator and the second capilary tube follows inside the second arm of the fork which forms the suction pipe leading to the refrigerator evaporator.

3. A unit according to any one of Claims 1 or 2 wherein the two evaporators are connected in series such that the flow of refrigerant from the refrigerator evaporator passes to the inlet of the freezer evaporator with only the freezer suction pipe being connected to the compressor inlet pipe.

4. A unit according to Claim 3 wherein the refrigerator suction pipe is connected to the inlet of the freezer evaporator and the two arms of the fork are sealed around the respective capillary tubes to ensure that the refrigerant flows into the freezer evaporator, there being a connection from the outlet of the freezer evaporator to the freezer suction pipe on the compressor side of said seals.

5. A refrigerator/freezer unit substantially as hereinbefore described with reference to the accompanying drawings.