System for controlling flow rate of refrigerant

• US 4,745,767 A
• Filed: 03/10/1987
• Issued: 05/24/1988
• Est. Priority Date: 07/26/1984
• Status: Expired due to Fees

• Current Assignee: Sanyo Electric Company Limited (Panasonic Holdings Corporation)
• Original Assignee: Sanyo Electric Company Limited (Panasonic Holdings Corporation)
• Inventors: Ohya, Satoshi, Hoshi, Katsuhiko
• Primary Examiner(s): Tanner, Harry B.
• Application Number:
  US07/024,365
• Time in Patent Office: 441 Days
• Field of Search: 62/223, 62/224, 62/225, 62/208, 62/209, 62/210, 62/211, 62/212, 62/205
• US Class Current: 62/211
• CPC Class Codes: F25B 2600/21 Refrigerant outlet evaporator temperature
• CPC Class Codes: F25B 2600/2513 Expansion valves
• CPC Class Codes: F25B 41/345 by solenoids
• CPC Class Codes: F25B 41/35 by rotary motors, e.g. by stepping motors
• CPC Class Codes: Y02B 30/70 Efficient control or regulation technologies, e.g. for control of refrigerant flow, motor or heating

Abstract

A system for controlling the flow rate of a refrigerant for refrigeration cycles which comprises an electronic expansion valve disposed at the inlet of an evaporator and a controller for controlling the opening-closing movement of the valve. The controller comprises a calculating unit for comparing the degree of superheat of the refrigerant measured at the evaporator with a preset degree of superheat and feeding a valve opening adjusting signal to the valve according to the value obtained by the comparison, and a valve full-closing signal generator for comparing the measured temperature of the space to be cooled with a preset temperature and feeding a valve full-closing signal to the valve based on the value obtained from the comparison of temperatures, in preference to the opening adjusting signal.

Claims

1. A system for controlling the flow rate of a refrigerant for use in refrigeration cycles comprising an electronic expansion valve provided at the inlet of an evaporator, and a controller for controlling the opening-closing movement of the valve, the controller comprising (i) a valve drive unit for opening or closing the valve, (ii) a unit for measuring the degree of superheat of the evaporator, (iii) a unit for measuring the temperature of the space to be cooled by the evaporator, (iv) calculating means for feeding a valve opening adjusting signal to the valve drive unit in accordance with a value obtained by comparing the measured degree of superheat, (v) a valve full-closing signal generator for feeding to the valve drive unit a valve full-closing signal in preference to the valve opening adjusting signal, whenever the temperature measured by the temperature measuring unit is lower than or equal to a preset temperature against which the measured temperature is compared, (vi) a first comparator for comparing the measured degree of superheat with the preset degree of superheat to produce a signal representing the deviation of the measurement from the preset degree of superheat, and (vii) an internal algorithmic unit for (1) correcting the deviation represented by the signal in order to exclude the influence of disturbances, (2) storing the resulting correction signal as a control data, and (3) feeding the control data associated with the last valve opening value stored at the time of initiation of said valve full-closing signal, to the valve drive unit as a reference value, for upon reopening said valve, causing the valve to initially open to a position substantially the same as at the initiation of said valve full-closing signal, for rapidly reinitiating control of the valve opening, whenever the valve is reopened.