DE102014200981A1 - A compressor for a refrigeration cycle of a household refrigerator, a household refrigerator with a compressor, and a method of operating a compressor of a household refrigerator - Google Patents

Abstract

The invention relates to a compressor (16) for a refrigeration circuit (14) of a household refrigerating appliance (10), comprising: a piston (36) movable within a compressor chamber (32) of a cylinder (34) for compressing a refrigerant, the piston (36) in the radial direction relative to the cylinder (34) can be stored without contact by means of a formable from the refrigerant gas pressure bearing; an inlet valve (42) for regulating a volume flow of the uncompressed refrigerant from a low pressure inlet (44) of the compressor (16) into the compressor chamber (32); an outlet valve (46) for regulating a volume flow of the compressed refrigerant from the compressor room (32) to a high pressure outlet (48) of the compressor (16); wherein the compressor (16) comprises a shut-off valve (50) arranged between the low-pressure inlet (44) and the high-pressure outlet (48), which is designed to return the refrigerant from the high-pressure outlet (48) to the low-pressure inlet (16) when the compressor (16) is deactivated ( 44). Furthermore, the invention relates to a domestic refrigeration appliance (10) with a compressor (16) and to a method for operating a compressor (16) of a refrigeration cycle (14) of a household refrigerating appliance (10).

Description

The invention relates to a compressor for a refrigeration cycle of a household refrigerating appliance and a method for operating a compressor of a domestic refrigerating appliance of the type specified in the preambles of the independent claims. Furthermore, the invention relates to a household refrigerating appliance with such a compressor.

The WO 2008 055810 A1 shows a linear compressor for a household appliance, with a longitudinal direction of a cylinder between an upper and lower dead center movable piston whose piston outer surface is to form a gas pressure bearing in the radial direction of the cylinder without contact against a corresponding cylinder inner surface storable. The linear compressor shown there can be used in a refrigeration cycle of a household refrigerator.

During a standstill period of such a compressor with a gas storage, it may be due to the gas storage to an undesirable backflow of a gaseous refrigerant from a high pressure outlet to a low pressure input of the compressor. The result is that a corresponding pressure difference between the high-pressure outlet and the low-pressure inlet during the downtime of such a compressor can not be maintained, which has a negative effect on the operation of a refrigeration cycle of a domestic refrigerator. Because at a restart of such a compressor, first, the pressure difference between the high pressure outlet and the low pressure inlet of the compressor must be rebuilt.

It is therefore the object of the present invention to be able to maintain a pressure difference between a low-pressure inlet and a high-pressure outlet of a compressor even during the downtime of the compressor.

This object is achieved by a compressor for a refrigeration cycle of a household refrigerator and by a method for operating a compressor of a refrigeration cycle of a household refrigerating appliance with the features of the independent claims and, moreover, by a household refrigerating appliance with such a compressor.

The compressor according to the invention for a refrigeration cycle of a household refrigerating appliance comprises a piston which is movable within a compressor chamber of a cylinder for compressing a refrigerant, wherein the piston can be stored without contact in the radial direction of the cylinder by means of a gas pressure bearing which can be formed from the refrigerant. Furthermore, the compressor comprises an inlet valve for regulating a volume flow of the uncompressed refrigerant from a low-pressure inlet of the compressor into the compressor chamber. Furthermore, the compressor comprises an outlet valve for regulating a volume flow of the compressed refrigerant from the compressor space to a high-pressure outlet of the compressor. In order to be able to maintain a pressure difference between the low-pressure inlet and the high-pressure outlet of the compressor established during operation of the compressor, it is provided according to the invention that the compressor comprises a shut-off valve arranged between the low-pressure inlet and the high-pressure inlet, which is designed for this purpose to prevent backflow of the refrigerant from the high-pressure outlet to the low-pressure inlet when the compressor is deactivated.

It is therefore provided according to the invention, in addition to the inlet valve and the outlet valve, which serve to regulate the volume flows of the refrigerant through the compressor, to provide a further shut-off valve within the compressor between the low-pressure inlet and the high pressure outlet, by means of which a flow through the compressor with the refrigerant at deactivated Compressor can be prevented. Because during the operation of the compressor, a pressure difference between the low-pressure inlet and the high-pressure outlet is constructed, which would lead to an undesired pressure equalization by deactivation of the compressor by a return flow of the refrigerant through the compressor. By the inventively provided shut-off valve, it is now possible to prevent this unwanted pressure equalization between the low-pressure inlet and the high-pressure outlet of the compressor by the shut-off valve is closed as soon as the compressor is deactivated. The solution according to the invention makes it possible to maintain a previously established pressure difference between the low-pressure inlet and the high-pressure outlet of the compressor during the downtime of the compressor, whereby a considerable increase in the efficiency of a refrigeration cycle of a household refrigerating appliance can be achieved, in which the compressor according to the invention is used. When the compressor is restarted, it is no longer necessary by the solution according to the invention initially to build up a pressure difference between the low-pressure inlet and the high-pressure inlet since the pressure difference previously built up during operation of the compressor is reliably maintained by the lockable shut-off valve even during standstill of the compressor can.

In an advantageous embodiment of the invention, it is provided that the shut-off valve in a Gas bearing supply line of the compressor is arranged, through which the refrigerant for forming the gas pressure bearing can be fed. In other words, the shut-off valve may be arranged directly in the gas bearing supply line of the compressor serving as a pressure line, whereby pressure equalization with the compressor switched off can be prevented by backflow of the refrigerant through the gas storage supply line.

In a further advantageous embodiment of the invention, it is provided that the shut-off valve is arranged in a refrigerant line of the compressor through which the compressed refrigerant flows in the direction of the high-pressure outlet when the compressor is activated. The accessibility of such a refrigerant line may be better than in the gas storage supply line, so that an optionally defective shut-off valve can be exchanged particularly easily. With the arrangement of the shut-off valve in the refrigerant line, which leads to the high-pressure outlet of the compressor, also an undesirable pressure equalization between the high-pressure outlet and the low-pressure inlet of the compressor can be effectively prevented when the compressor is deactivated.

According to a further advantageous embodiment of the invention, it is provided that the shut-off valve is designed as a check valve. For example, the shut-off valve may be formed as a louvered valve, spring valve or the like, which can be actuated solely by the pressure difference between the low-pressure inlet and the high-pressure outlet of the compressor. Such a shut-off valve is usually relatively simple and can therefore be manufactured and provided particularly cost.

In a further advantageous embodiment of the invention, it is provided that the shut-off valve is electromotive or electromagnetically actuated. In other words, it can be provided that the shut-off valve is an active element, in which the valve position can be influenced, for example, by applying an electric current. The advantage with such a configuration is that the shut-off valve can be activated actively, whereby its operation is essentially independent of the prevailing pressure conditions within the compressor freely selectable.

A further advantageous embodiment of the invention provides that the compressor is designed as a linear compressor. Linear compressors are usually piston compressors, in which the pistons are driven by linear drives, for example roller screw drives, independently of a crankshaft. Compared with conventional reciprocating compressors with a rotary drive, for example via a connecting rod driven by a rotary motor, linear compressors have the advantage that the piston stroke can be changed. This makes it possible to adjust the compression ratio within the compressor in a particularly simple manner as needed.

In a further advantageous embodiment of the invention, it is provided that the cylinder comprises a socket, within which the piston is arranged. For example, if due to a defect, the gas pressure bearing can not be formed, the piston only comes into contact with the socket, within which it is guided, so that in such a case, only the socket is damaged and it must be replaced.

A further advantageous embodiment of the invention provides that the bushing comprises a plurality of openings through which the refrigerant for supplying the gas pressure bearing in the direction of the piston can be fed. Preferably, these openings are provided evenly distributed on the socket, so that the gas pressure bearing can be constructed very quickly and evenly.

The domestic refrigerator according to the invention comprises the compressor according to the invention or an advantageous embodiment of the compressor according to the invention.

According to an advantageous embodiment of the domestic refrigerator, it is provided that the compressor is arranged in the flow direction of a refrigeration cycle of the household refrigerating appliance after an evaporator and a condenser, wherein a further shut-off valve is arranged in the flow direction after the condenser and in front of the evaporator. In this case, the flow direction of the refrigerant within the refrigeration cycle is designated by the flow direction, in which the refrigerant flows through the refrigeration cycle when the compressor is activated. The fact that a further shut-off valve is arranged after the condenser and before the evaporator, an undesirable pressure equalization with deactivated compressor between the condenser and the evaporator can be prevented because the condenser is a high pressure side and the evaporator is a low pressure side of the refrigeration cycle. This also contributes to increasing the efficiency of the refrigeration cycle of the household refrigeration appliance, because a pressure equalization between the condenser and evaporator can be prevented by closing the other shut-off valve.

In the method according to the invention for operating a compressor of a refrigeration cycle of a household refrigerating appliance, a refrigerant is heated by means of a compressor within a compressor room Cylinder movable piston compressed, which is mounted in the radial direction relative to the cylinder without contact by means of a formed from the refrigerant gas pressure bearing. In this case, an inlet valve of the compressor for regulating a volume flow of the uncompressed refrigerant from a low pressure input of the compressor is actuated in the compressor chamber. Furthermore, an exhaust valve of the compressor for regulating a volume flow of the compressed refrigerant from the compressor space to a high-pressure outlet of the compressor is actuated. The method according to the invention is characterized in that a shut-off valve arranged between the low-pressure inlet and the high-pressure outlet is closed as soon as the compressor is deactivated, whereby a backflow of the refrigerant from the high-pressure outlet to the low-pressure inlet is prevented when the compressor is deactivated. Advantageous embodiments of the compressor according to the invention are to be regarded as advantageous embodiments of the method according to the invention for operating such a compressor.

In a further advantageous embodiment of the method, it is provided that the shut-off valve is opened with a predetermined time course, before the deactivated compressor for compressing the refrigerant is activated again. Preferably, the time advance before the activation of the compressor is chosen to be so large that the gas pressure bearing between the piston and the cylinder is completely formed by means of the refrigerant flowing from the high-pressure outlet into the compressor. In other words, the shut-off valve is opened against a prevailing pressure gradient when the compressor is deactivated, so that due to the prevailing pressure gradient between the high-pressure outlet and the low-pressure inlet of the compressor, the refrigerant flows into the compressor and the gas pressure bearing between the piston and the cylinder is formed, even before the Compressor is reactivated. As a result, the piston can already be mounted without contact relative to the cylinder before the compressor is activated. As a result, the wear on the piston-cylinder mating can be significantly reduced.

Further advantages, features and details of the invention will become apparent from the following description of preferred embodiments and from the drawing. The features and feature combinations mentioned above in the description as well as the features and feature combinations mentioned below in the description of the figures and / or in the figures alone can be used not only in the respectively specified combination but also in other combinations or in isolation, without the scope of To leave invention.

The drawing shows in:

1 a schematic longitudinal sectional view of a household refrigerator with a compressor;

2 , a schematic representation of a refrigeration cycle of the household refrigerator, within which the compressor is arranged;

3 a schematic side sectional view of a first embodiment of the compressor; and

4 a schematic side sectional view of a second embodiment of the compressor.

In the figures, identical or functionally identical elements are provided with the same reference numerals.

A household refrigerator 10 is in 1 shown in a schematic longitudinal sectional view. In the household refrigerator 10 it may be, for example, a refrigerator, a freezer or a combination refrigerator-freezer. The household refrigerator 10 includes an interior 12 , which is designed to receive food. This interior 12 may be a refrigerated compartment, a freezer or a no-frost compartment, or at least two of these compartments.

The household refrigerator 10 includes a refrigeration cycle 14 , which is a compressor designed as a linear compressor 16 includes. The compressor 16 is preferably in a machine room 18 Standing in the lower and rear of the household refrigerator 10 is located.

In 2 is the refrigeration cycle 14 shown in a schematic representation. Next to the compressor 16 includes the refrigeration cycle 14 a liquefier 20 , a throttle 22 , which may also be an expansion valve or the like, and an evaporator 24 , In addition, the compressor includes 16 a shut-off valve 50 , which will be discussed in more detail below. Furthermore, the refrigeration cycle includes 14 another shut-off valve 28 , With the arrow 30 is a flow direction of the refrigeration cycle 14 indicated, in which a non-designated refrigerant flows, as long as the compressor 16 is activated.

The compressor 16 is thus in the flow direction 30 of the refrigeration cycle 14 after the evaporator 24 and before the liquefier 20 arranged, with the further shut-off valve 28 in the flow direction 30 after the condenser and before the Evaporator 24 , in the present case, before the throttle 22 , is arranged.

In 3 is a schematic side sectional view of a first embodiment of the compressor 16 shown. The compressor 16 includes one within a compressor room 32 a cylinder 34 movable piston 36 for compressing an unspecified refrigerant, wherein the piston 36 in its radial direction relative to the cylinder 34 can be stored without contact by means of a gas pressure bearing which can be formed from the refrigerant. The cylinder 34 in the present case comprises a socket 38 , inside which the piston 36 is arranged. The socket 38 has several openings 40 on, through which the refrigerant to form the gas pressure bearing in the direction of the piston 36 can be fed.

Furthermore, the compressor points 16 an inlet valve 42 which is for regulating a volume flow of the uncompressed refrigerant from a low pressure input 44 of the compressor 16 in the compressor room 32 serves. The low pressure input 44 is on a housing 35 of the compressor 16 arranged and within the refrigeration cycle 14 to the evaporator 24 connected so that the refrigerant with activated compressor 16 from the evaporator 24 over the low pressure entrance 44 the compressor 16 is supplied.

The compressor 16 further includes an exhaust valve 46 for regulating a volume flow of the compressed refrigerant from the compressor room 32 to a high pressure outlet 48 of the compressor 16 , which also on the housing 35 is arranged. The high pressure outlet 48 is inside the refrigeration cycle 14 with the liquefier 20 connected. The compressed refrigerant is thus via the high pressure outlet 48 the liquefier 20 fed.

The compressor 16 includes one between the low pressure input 44 and the high pressure outlet 48 arranged shut-off valve 50 , which is designed with the compressor off 16 a return flow of the refrigerant from the high pressure outlet 48 to the low pressure input 44 to prevent. In other words, the shut-off valve 50 when the compressor is deactivated 16 be closed, allowing one during operation of the compressor 16 established pressure difference between the high pressure outlet 48 and the low pressure input 44 can be maintained.

In the present case is the shut-off valve 50 in a gas storage supply line 52 of the compressor 16 arranged, through which the refrigerant for forming the gas pressure bearing can be fed. The gas storage supply line 52 leads from a high pressure side of the compressor 16 in a reservoir 41 from where the refrigerant passes through the openings 40 the socket 38 in the direction of the piston 36 can be fed to the gas pressure bearing between the piston 36 and the socket 38 train.

The shut-off valve 50 can be designed as a simple check valve, such as a louvered valve, spring valve or the like. In this case, the shut-off valve 50 independently by a pressure difference between the high pressure outlet 48 and the low pressure input 44 of the compressor 16 closed. Alternatively, it is also possible that the shut-off valve 50 is designed as an active element and, for example, electromotive or electromagnetically actuated.

In 4 is a schematic side sectional view of another embodiment of the compressor 16 shown. Unlike in 3 shown embodiment of the compressor 16 is in the case shown here, the shut-off valve 50 in a high pressure side refrigerant line 54 of the compressor 16 arranged, through which the compressed refrigerant with activated compressor 16 in the direction of the high pressure outlet 48 flows.

The following is a method of operating the compressor 16 explained. With compressor activated 16 is the refrigerant by means of within the compressor room 32 inside the cylinder 34 moving piston 36 compressed, the piston 36 in its radial direction relative to the cylinder 34 is stored without contact by means of the formed from the refrigerant gas pressure bearing. About the gas storage supply line 52 is doing continuously refrigerant into the gas reservoir 41 transported and through the openings 40 in the direction of the piston 36 supplied, whereby the gas pressure bearing, which is formed from the refrigerant, is supplied with a sufficient pressure.

As long as the compressor 16 is in operation, the inlet valve 42 and the exhaust valve 46 cyclically and alternately actuated to control the volume flow of the refrigerant from the low pressure input 44 through the compressor room 32 over the high pressure outlet 48 to regulate.

As soon as the compressor 16 is deactivated, this is between the low pressure input 44 and the high pressure outlet 48 arranged shut-off valve 50 closed, whereby a return flow of the refrigerant from the high-pressure outlet 48 to the low pressure input 44 when the compressor is deactivated 16 is prevented. At the same time, the further shut-off valve will be added 28 which is like in 2 shown within the refrigeration cycle 14 between the liquefier 20 and the throttle 22 is arranged, closed as soon as the compressor 16 disabled becomes. This will provide pressure equalization between the condenser 20 and the evaporator 24 when the compressor is deactivated 16 prevents the refrigerant from flowing down the condenser 20 not in the direction of the evaporator 24 can flow.

That inside the compressor 16 arranged shut-off valve 50 is opened with a predetermined time delay before the deactivated compressor 16 is reactivated to compress the refrigerant. In this case, the time advance before activating the compressor 16 chosen so large that by means of the high-pressure outlet 48 in the compressor 16 inflowing refrigerant the gas pressure bearing between the piston 36 and the cylinder 34 is fully formed before the compressor 16 is activated again. This ensures that the gas pressure bearing between the piston 36 and the cylinder 34 fully formed before the compressor 16 is activated again and the piston 36 inside the cylinder 34 moved to compress the refrigerant.

LIST OF REFERENCE NUMBERS

10

 Household refrigerator

12

 inner space

14

 Refrigeration circuit

16

 compressor

18

 engine room

20

 condenser

22

 throttle

24

 Evaporator

28

 shut-off valve

30

 flow direction

32

 compressor room

34

 cylinder

35

 casing

36

 piston

38

 Rifle

40

 opening

41

 reservoir

42

 intake valve

44

 Low pressure input

46

 outlet valve

48

 High pressure outlet

50

 shut-off valve

52

 Gas bearing supply line

54

 Refrigerant line

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• WO 2008055810 A1 [0002]

Claims (13)

Compressor ( 16 ) for a refrigeration cycle ( 14 ) of a household refrigerating appliance ( 10 ), with - one within a compressor room ( 32 ) of a cylinder ( 34 ) movable piston ( 36 ) for compressing a refrigerant, wherein the piston ( 36 ) in its radial direction relative to the cylinder ( 34 ) Can be stored without contact by means of a formable from the refrigerant gas pressure bearing; - an inlet valve ( 42 ) for regulating a volume flow of the uncompressed refrigerant from a low pressure input ( 44 ) of the compressor ( 16 ) in the compressor room ( 32 ); - an outlet valve ( 46 ) for regulating a volume flow of the compressed refrigerant from the compressor room ( 32 ) to a high pressure outlet ( 48 ) of the compressor ( 16 ); characterized in that the compressor ( 16 ) between the low pressure input ( 44 ) and the high pressure outlet ( 48 ) arranged shut-off valve ( 50 ), which is designed, with deactivated compressor ( 16 ) a return flow of the refrigerant from the high-pressure outlet ( 48 ) to the low pressure input ( 44 ) to prevent. Compressor ( 16 ) according to claim 1, characterized in that the shut-off valve ( 50 ) in a gas storage supply line ( 52 ) of the compressor ( 16 ) is arranged, through which the refrigerant for forming the gas pressure bearing can be fed. Compressor ( 16 ) according to claim 1, characterized in that the shut-off valve ( 50 ) in a refrigerant line ( 54 ) of the compressor ( 16 ) is arranged, through which the compressed refrigerant with activated compressor ( 16 ) in the direction of the high-pressure outlet ( 48 ) flows. Compressor ( 16 ) according to one of the preceding claims, characterized in that the shut-off valve ( 50 ) is designed as a check valve. Compressor ( 16 ) according to one of claims 1 to 3, characterized in that the shut-off valve ( 50 ) is electromotive or electromagnetically actuated. Compressor ( 16 ) according to one of the preceding claims, characterized in that the compressor ( 16 ) is designed as a linear compressor. Compressor ( 16 ) according to one of the preceding claims, characterized in that the cylinder ( 34 ) a socket ( 38 ), within which the piston ( 36 ) is arranged. Compressor ( 16 ) according to claim 7, characterized in that the bushing ( 38 ) several openings ( 40 ), through which the refrigerant for forming the gas pressure bearing in the direction of the piston ( 36 ) can be fed. Household refrigeration appliance ( 10 ) with a compressor ( 16 ) according to any one of the preceding claims. Household refrigeration appliance ( 10 ) according to claim 9, characterized in that the compressor ( 16 ) in the flow direction ( 30 ) of a refrigeration cycle ( 14 ) of the household refrigerating appliance ( 10 ) after an evaporator ( 24 ) and in front of a condenser ( 20 ), wherein a further shut-off valve ( 28 ) in the flow direction ( 30 ) after the liquefier ( 20 ) and in front of the evaporator ( 24 ) is arranged. Method for operating a compressor ( 16 ) of a refrigeration cycle ( 14 ) of a household refrigerating appliance ( 10 ), comprising the steps of: - compressing a refrigerant by means of one inside a compressor chamber ( 32 ) of a cylinder ( 34 ) moving piston ( 36 ), which in its radial direction relative to the cylinder ( 34 ) Is mounted without contact by means of a formed from the refrigerant gas pressure bearing; - actuating an inlet valve ( 42 ) of the compressor ( 16 ) for regulating a volume flow of the uncompressed refrigerant from a low pressure input ( 44 ) of the compressor ( 16 ) in the compressor room ( 32 ); - actuating an exhaust valve ( 46 ) of the compressor ( 16 ) for regulating a volume flow of the compressed refrigerant from the compressor room ( 32 ) to a high pressure outlet ( 48 ) of the compressor ( 16 ); characterized in that a between the low pressure input ( 44 ) and the high pressure outlet ( 48 ) arranged shut-off valve ( 50 ) is closed as soon as the compressor ( 16 ) is deactivated, whereby a return flow of the refrigerant from the high-pressure outlet ( 48 ) to the low pressure input ( 44 ) with the compressor deactivated ( 16 ) is prevented. Method according to claim 11, characterized in that the shut-off valve ( 50 ) is opened with a predetermined time delay before the deactivated compressor ( 16 ) is reactivated to compress the refrigerant. A method according to claim 12, characterized in that the time advance before activating the compressor ( 16 ) so large that by means of the high-pressure outlet ( 48 ) in the compressor inflowing refrigerant the gas pressure bearing between the piston ( 36 ) and the cylinder ( 34 ) is formed.

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