Cooling control system and expansion valve therefor

• US 4,506,518 A
• Filed: 04/30/1984
• Issued: 03/26/1985
• Est. Priority Date: 06/17/1981
• Status: Expired due to Fees

• Current Assignee: Pacific Industrial Company Limited
• Original Assignee: Pacific Industrial Company Limited
• Inventors: Yamada, Hideo, Okubo, Yoichi, Yoshikawa, Seimi
• Primary Examiner(s): Wayner, William E.
• Application Number:
  US06/605,487
• Time in Patent Office: 330 Days
• Field of Search: 62/204, 62/180, 62/227
• US Class Current: 62/180
• CPC Class Codes: F16K 1/54 Arrangements for modifying the way in which the rate of flow varies during the actuation of the valve
• CPC Class Codes: F16K 31/04 using a motor
• CPC Class Codes: F16K 31/082 using a electromagnet and a permanent magnet
• CPC Class Codes: F16K 31/50 with screw-spindle or internally threaded actuating means
• CPC Class Codes: F16K 37/005 for measuring fluid parameters F16K37/0033 takes precedence
• CPC Class Codes: F16K 41/04 with at least one ring of rubber or like material between spindle and housing
• CPC Class Codes: F24F 11/30 for purposes related to the operation of the system, e.g. for safety or monitoring
• CPC Class Codes: F24F 11/46 Improving electric energy efficiency or saving
• CPC Class Codes: F24F 11/63 Electronic processing
• CPC Class Codes: F24F 11/81 by controlling the air supply to heat-exchangers or bypass channels
• CPC Class Codes: F24F 11/84 using valves
• CPC Class Codes: F24F 11/86 by controlling compressors within refrigeration or heat pump circuits
• CPC Class Codes: F24F 2110/10 Temperature
• CPC Class Codes: F25B 2600/0253 with variable speed
• CPC Class Codes: F25B 2600/2513 Expansion valves
• CPC Class Codes: F25B 2700/21172 at the inlet
• CPC Class Codes: F25B 2700/21174 of the refrigerant at the inlet of the evaporator
• CPC Class Codes: F25B 2700/21175 of the refrigerant at the outlet of the evaporator
• CPC Class Codes: F25B 41/35 by rotary motors, e.g. by stepping motors
• CPC Class Codes: F25B 49/02 for compression type machines, plants or systems
• CPC Class Codes: G05D 23/1917 : using digital means
• CPC Class Codes: Y02B 30/70 : Efficient control or regulation technologies, e.g. for control of refrigerant flow, motor or heating

Abstract

A cooling control system comprises a cooling apparatus having a refrigerant compressor, a vapor condenser, an expansion valve, an evaporator and a blower, a first temperature detection device for detecting a room temperature, a second temperature detection device for detecting a temperature of the refrigerant which is introduced into the evaporator, a detection device for detecting a temperature difference between a temperature of the refrigerant discharged from the evaporator and the temperature of the refrigerant introduced into the evaporator, and a control device for controlling operations of the compressor as well as the blower and for controlling an opening of the expansion valve in response to the detected inflowing refrigerant temperature, the detected temperature difference and the detected room temperature.

Claims

1. A cooling control system comprising a cooling apparatus having a refrigerant compressor, a vapor condenser to condense refrigerant pressurized by the compressor, an expansion valve means for controlling flow rate of the refrigerant and for expanding the refrigerant condensed by the condenser under pressure, an evaporator for evaporating the expanded refrigerant, and a blower for directing fluid to be cooled to the evaporator,

a first temperature detection means for detecting a temperature of the fluid to be cooled,

a second temperature detection means for detecting a temperature of the refrigerant which is introduced into the evaporator,

a detection means for detecting a temperature difference between a temperature of the refrigerant discharged from the evaporator and the temperature of the refrigerant introduced into the evaporator, and

a control means for controlling operations of the compressor as well as the blower and for controlling an opening of the expansion valve means in response to the temperature of the refrigerant introduced into the evaporator detected by the second temperature detection means, the temperature difference detected by the temperature difference detection means, and the temperature of the fluid detected by the first temperature detection means.

2. A cooling control system according to claim 1, wherein the temperature difference detection means comprises a third temperature detection means for detecting the temperature of the refrigerant discharged from the evaporator, and a subtraction means for calculating difference between the temperature detected by the second temperature detection means and the temperature detected by the third temperature detection means.

3. A cooling control system according to claim 1, wherein the control means comprises

a first discriminator means for comparing the temperature detected by the first temperature detection means with at least one first reference temperature level,

a second discriminator means for comparing the temperature detected by the second temperature detection means with at least one second reference temperature level,

a third discriminator means for comparing the temperature difference detected by the temperature difference detection means with at least one reference temperature difference level, and

a control condition selector for controlling operations of the compressor as well as the blower and for controlling the opening of the expansion valve means according to the comparisons by the first, second and third discriminator means.

4. A cooling control system according to claim 3, wherein

the first discriminator means compares the temperature detected by the first temperature detection means with two first reference temperature levels,

the second discriminator means compares the temperature detected by the second temperature detection means with two second reference temperature levels, and

the third discriminator means compares the temperature difference detected by the temperature difference detection means with two reference temperature difference levels.

5. A cooling control system according to claim 4, wherein

the control condition selector is adapted to stop the operation of the compressor and to make the blower generate weak wind when the temperature detected by the first temperature detection means is not greater than a lower temperature level of said two first reference temperature levels according to the comparison by the first discriminator means.

6. A cooling control system according to claim 5, wherein

the control condition selector is adapted to decrease the opening of the expansion valve means when the temperature detected by the first temperature detection means is not greater than the lower temperature level of the first reference temperature levels according to the comparison.

7. A cooling control system according to claim 4, wherein

the control condition selector is adapted to decrease the opening of the expansion valve means when the temperature detected by the first temperature detection means is greater than a lower temperature level of said two first reference temperature levels, and when the temperature detected by the second temperature detection means is not less than a higher temperature level of said two second reference temperature levels according to the comparisons by the first and second discriminator means.

8. A cooling control system according to claim 4 wherein

when the temperature detected by the first temperature detection means is greater than a lower temperature level of said two first reference temperature levels and when the temperature detected by the second temperature detection means is less than a higher temperature level of said two second reference temperature levels according to the comparisons by the first and second discriminator means,

a control condition selector is adapted to decrease the opening of the expansion valve means when the detected temperature difference is not greater than a lower temperature difference level of said two reference temperature difference levels according to the comparison by the third discriminator means,

to keep the opening as it is when the detected temperature difference is greater than the lower temperature difference level, and less than a higher temperature difference level of said two reference temperature difference levels according to the comparison, and

to increase the opening of the expansion valve means when the detected temperature difference is not less than the higher temperature difference level according to the comparison.

9. A cooling control system according to claim 4, wherein

the control condition selector is adapted to make the compressor in medium level of operation and to make the blower generate medium level of wind when the temperature detected by the first temperature detection means is greater than a lower temperature level of said two first reference temperature levels and less than a higher temperature level of said two first reference temperature levels according to the comparison by the first discriminator means.

10. A cooling control system according to claim 4, wherein

the control condition selector is adapted to make the blower generate strong wind when the temperature detected by the first temperature detection means is not less than a higher temperature level of said two first reference temperature levels according to the comparison by the first discriminator.

11. A cooling control system according to claim 10, wherein

the control condition selector is adapted to make the compressor in medium level of operation, when the temperature detected by the first temperature detection means is not less than the higher temperature level, and when the temperature detected by the second temperature detection means is not greater than a lower temperature level of said two second reference temperature levels according to the comparisons by the first and second discriminator means.

12. A cooling control system according to claim 10, wherein

the control condition selector is adapted to make the compressor in full level of operation, when the temperature detected by the first temperature detection means is not less than the higher temperature level, and when the temperature detected by the second temperature detection means is greater than a lower temperature level of said two second reference temperature levels according to the comparisons by the first and second discriminator, means.

13. A cooling control system according to claim 1, wherein

the control means comprises a microprocessor.

14. A cooling control system according to claim 1, wherein the opening of the expansion valve means linearly depends on displacement of a valve stem thereof with respect to a valve body thereof.

15. A cooling control system according to claim 14, wherein

the expansion valve means comprises

the valve body having a threaded portion

the valve stem having a valve portion

to change the opening of the expansion valve means in cooperation with the valve body when the valve stem is axially displaced with respect to the valve body, the valve stem further having a threaded portion engaged with the threaded portion of the valve body and being axially displaced with respect to the valve body when the valve stem is rotated around an axis of the threaded portion thereof, and

a motor means coupled to the control means, the motor means having a stator portion fixed to the valve body and a rotor portion fixed to the valve stem in order to rotate

the valve stem around the axis of the threaded portion thereof.

16. A cooling control system according to claim 15, wherein

the rotor portion is rotated by a certain angle in response to a control signal given from the control means to the motor means.

17. A cooling control system according to claim 15, wherein the opening of the expansion valve means is linearly dependent on the rotational angle of the stem.

18. A cooling control system according to claim 17, wherein the valve portion is generally conical in shape.

19. A cooling control system according to claim 18, wherein the valve portion comprises a needle valve.

20. A cooling control system according to claim 15, wherein the threaded portion of the valve body comprises an internal thread part, and the threaded portion of the valve stem comprises an external thread part.

21. A cooling control system according to claim 15, wherein the valve stem has the threaded portion at a remote end thereof from the valve portion.

22. A cooling control system according to claim 21, wherein the valve body has a bearing portion supporting the valve stem at an intermediate portion thereof between the valve portion and the threaded portion of the valve stem.

23. A cooling control system according to claim 15, wherein the control means comprises a microprocessor.