FR2473649A1 - SENSITIVE CONTROL DEVICE AT TEMPERATURE - Google Patents

Abstract

The temperature sensitive control device for air conditioning apparatus comprising an automatic expansion valve 20 and a control device 28. The automatic expansion valve 20 is connected between the condenser 14 and the evaporator 24 in order to maintain a relatively constant pressure. in the evaporator. The controller comprises a compressor housing bypass valve 28 responsive to the temperature of the refrigerant leaving the evaporator to control the capacity of the compressor. The control device further comprises a thermosensitive ball 50 mounted at the outlet of the evaporator to detect the temperature at the outlet of the evaporator. (CF DRAWING IN BOPI)

Description

The present invention relates to compressors and more particularly to

  a temperature sensitive control system used with variable generated volume compressors. The invention has particular applications in variable-volume rotary-type compressors of the swing-plate type used in air-conditioning systems.

  and / or automobile refrigeration.

  In U.S. Patent No. 3,959,983 to R. W. Roberts et al.

  1976, and attributed to the plaintiff, it is described a

  controlled variable volume, oscillating plate presser which includes a capacity control system having a main control valve. The control valve includes a valve member for controlling the flow of gas between the compressor housing and the gas suction line. The valve member is controlled in response to the pressure detected in the suction line by means of

  of a membrane which is pre-loaded in the opposite direction

using a spring.

  In the present invention, there is provided a temperature responsive control system which includes an automatic relief valve and a compressor crank bypass valve to control the compressor capacity at the compressor.

  partial loads to reduce losses.

  2. Accordingly, it is a general object of the present invention to provide an improved capacity control system for use with conventional compressors.

generated volume variable.

  Another object of the present invention is to provide a temperature sensitive control device for use in an air conditioning apparatus which comprises an automatic relief valve and a check valve.

  bypassing the compressor housing to control the capaci-

  Compressor tee at partial loads.

  Another object of the present invention is to provide a temperature-sensitive control system which comprises a bypass valve of the compressor housing having an enclosure and a membrane disposed in the enclosure so as to

  respond to the refrigerant temperature at the outlet of the evaporator

  porateur. Another object of the invention is to provide a temperature sensitive control system which comprises a bypass valve of the compressor housing and a ball

  temperature sensor mounted at the outlet of the evaporator for detecting

  temperature in order to control the operation of the

  fart. According to the present invention, there is provided a temperature-sensitive control system for use with

  in an air-conditioning apparatus of the type comprising a

  variable volume generating pressure, a condenser, an evapo-

  controller, and driving means for connecting the compressor, condenser and evaporator to provide a closed system for refrigerant flow. The system of

  temperature-sensitive control includes an automatic damper

  tick of relaxation and a control device. The flapper

  The expansion valve is connected between the condenser and the evaporator to maintain a constant relative pressure in the evaporator. The control device consisting of a bypass valve of the compressor housing responds to the

  refrigerant temperature at the evaporator outlet for.

  control the capacity of the compressor.

  3. The present invention will be well understood during the

  following description made in connection with the drawing

seal in which:

  The single figure is a schematic representation

  than a temperature-sensitive control device

  constructed in accordance with the present invention.

  In connection more particularly with the figure,

  a temperature-sensitive control system has been shown

  a refrigeration system generally designated by the reference numeral 10. The refrigeration system 10 comprises a compressor 12 with variable generated volume, preferably

  oscillating plate type, which compresses the refrigerant vapor

  G5rant and provides it to a condenser 14 via a pipe 16. The refrigerant is condensed in liquid form in the condenser and transmitted via

  of a pipe 18 has an automatic expansion valve 20.

  After the refrigerant has passed through the expansion valve, it flows through line 22 to an evaporator 24 which cools air or other fluid that passes over the surfaces of the evaporator. Refrigerant

  is then returned via a suction line

  ration 26 at the compressor inlet 12.

  The automatic expansion valve 20 is of the type

  pressure sensitive to maintain relative pressure

  constant temperature in the evaporator 24. The regulating valve 20

  the pressure can be of any conventional type

  to those illustrated and described in the United States Patent

  United States No. 3,688,516 to AB Newton, September 5, 1972. This type of valve detects a pressure drop to open in order to allow more refrigerant to flow and close as a result of an increase in pressure. pressure. This valve is also provided with means allowing

  to adjust the control point to obtain different

  pressure settings for the evaporator.

  The temperature-sensitive control system

  according to the present invention comprises a valve 28 for

  4. the compressor housing having an enclosure 30 and a pressure sensitive means, for example, a membrane of

  control 32 disposed inside the enclosure 30 to form a

  separate chambers 34 and 36. A check valve member

  conical me 38 is connected to one end of the valve stem

  which is fixed at its opposite end to the membrane 32.

  A spiral spring 42 is disposed in a chamber 44 against an upper portion of the valve member 38 and expands to exert a biasing force on the valve member downwardly. The valve member 38 is located above a

  orifice or opening 46 formed by the surfaces 48 of a-flas-

  than inside. The orifice 46 can be progressively opened

  by an upward movement of the valve member 38 elongates

of the surfaces of the flange 48.

  To detect the refrigeration temperature of

  the suction line, means sensitive to the temperature

  ture, for example, a ball 50 filled with coolant, thermo-

  mosensible, is mounted at the outlet of the evaporator 24 which

  responds to the temperature of the evaporator outlet refrigerant.

  The ball 50 communicates with the chamber 34 of the chamber 30 via a capillary tube 52. The chamber 36 communicates with the pressure of the compressor housing via a pipe 54. The chamber 44 communicates with the inlet of the suction pipe 26 of the compressor 12 through the pipe 56. It can thus be seen that the vertical movement of the rod 40 and the

  valve 38 controls the amount of leakage gas between the cartridge

  compressor and the suction inlet 26 which increases or decreases the crankcase pressure in response to the temperature

  refrigerant evaporator, thus causing an increase in

  or a decrease in piston stroke and volume

  generated by the compressor. For a detailed description of

  operation of the swash plate mechanism due to varia-

  In the case of crankcase pressure, reference should be made to US Pat. No. 3,861,829 to R. W. Roberts and R. D. Salle, dated January 21, 1975, entitled: "Variable

Capacity Wobble Plate Compressor ".

5.

  When the compressor 12 operates with a capacitor

  relatively small, the valve member 38 closes the opening

  fice 46 since the combination of the suction pressure in the pipe 56 and the expansion force of the spring 42 is much greater than the pressure exerted on the underside of the membrane 34 by the refrigerant gas of the ball 50. As a result of the closed position of the valve member 38, there is

  increased pressure in the compressor casing 12 provoked

  as for a corresponding minimum piston stroke and thus a minimum generated volume of the compressor. As the charge of the refrigerant is increased, there is an increase in the temperature of the refrigerant at the outlet of the evaporator which relaxes the refrigerant gas in the ball 50 to create

  higher pressures on the lower part of the

  brane 34. This causes an upward movement of the

  position of the valve stem 40 thus opening gradually

  In return, the crankcase pressure will be reduced allowing the volume generated by the compressor to be increased and the suction pressure in line 56 to be lowered. In response to the drop in pressure, suction, the automatic expansion valve will open

  to provide more refrigerant at increasing load.

  When refrigerant charge demands become

  will be satisfied, the temperature of the refrigerant at the outlet of the evaporator will decrease to gradually cause the closing of the orifice 46 and increase the pressure in

  the casing thus reducing the stroke of the compressor 12.

  besides the automatic expansion valve 20 will close at the

  following the increase of the suction pressure,

  thus, the flow of refrigerant.

  From the detailed description above, one can

  thus see that the present invention provides a sensing device

  the improved temperature which includes an automatic expansion valve and a crankcase bypass valve.

  compressor to control the capacity of the compressor to

  to reduce losses. In addition, the system

  temperature-sensitive control system includes a

  6. The thermosensitive mounted at the outlet of the evaporator for

detect the temperature.

  The present invention is not limited to the examples

  These embodiments, which have just been described, are, on the contrary, susceptible of variations and modifications which

will appear to those skilled in the art.

7.

Claims (4)

  1 - Air conditioning device of the type comprising a compressor with variable generated volume, a condenser, a   evaporator and driving means for connecting the compres-   the condenser and the evaporator in order to achieve a   closed system for the circulation of refrigerant fluid,   characterized in that it comprises a sensing control device   temperature range comprising an automatic expansion valve   tick (20) connected between the condenser and the evaporator to maintain a constant relative pressure in the evaporator; and control means (28) responsive to the refrigerant temperature at the evaporator outlet for controlling the compressor capacity.   2 - Air conditioning device according to the   cation 1, characterized in that the control means (28) comprises a bypass valve of the compressor housing having an enclosure (30) and a pressure sensitive means (32) disposed in this enclosure.   3 - Air conditioning device according to the   cation 1, characterized in that the control means (28) comprises   takes a temperature sensitive ball (50) mounted at the outlet of the evaporator to detect the temperature at the outlet of the evaporator.   4 - Air conditioning device according to the   cation 2, characterized in that the pressure sensitive means sion comprises a membrane (32).   - An air conditioning device according to claim 2, characterized in that the bypass valve (28)   further comprises an orifice (40) which is progressively   green so as to reduce the pressure of the compressor housing and therefore increase the volume generated by the compressor.