JPH053851U - Condensing pressure controller for refrigerator - Google Patents

Abstract

(57) [Abstract] [Purpose] The condensing pressure Pc and the evaporating pressure Pe are detected from the inside of the pipe 8 and the condensing pressure Pc is controlled based on the evaporating pressure Pe to operate the refrigerator economically. .. [Composition] A refrigeration cycle in which a refrigerator connects a compressor 1, a condenser 2, a pressurizing pump 4, an expansion valve 5, and an evaporator 6 with a pipe 8 for circulating a refrigerant, and a sensor 10 installed in the pipe 8. 1
The controller 12 controls the operation of the fan 9 of the condenser 2 in response to the signal from the controller 1. The controller 12 controls the condensation pressure Pc.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention is provided with a refrigeration cycle including a compressor, a condenser, an expansion valve, and an evaporator, and more particularly to a device for controlling the condensation pressure in a refrigerator using an air-cooled condenser.

[0002]

[Prior Art]

 There are several types of condensers for refrigerators, such as water-cooled type, evaporation type, and air-cooled type. Among them, the air-cooled type does not require cooling water and is simple in structure and maintenance. Is often used in. However, in the air-cooled type, the condensing temperature is easily influenced by the outside air temperature because the fan is rotated to blow the surrounding air to the condenser to cool it. In winter, the condensing pressure decreases as the outside air temperature decreases. As a result, the pressure difference between the condensing pressure and the evaporating pressure becomes smaller than the appropriate value for operating the expansion valve. As this pressure difference became smaller than the appropriate value, the proportion of flash gas generated from the refrigerant, which should be liquid when passing through the expansion valve, increased, and the refrigeration capacity decreased. If the load on the evaporator side is large, the condensing temperature rises, so it is necessary to increase the air flow rate.If the condensing pressure drops, stop the fan rotation and Was preventing it from being lowered too much.

[0003]

[Problems to be solved by the device]

 Therefore, in refrigerating machines that use air-cooled condensers, the condensing pressure is generally set to a constant high value in order to make it less susceptible to the influence of the outside temperature and to cope with the increase and decrease of the load. Was there. However, setting a high condensing pressure has the disadvantage of increasing the amount of compression work required in the compressor, and also increasing the amount of power used and the maintenance costs of the equipment. Therefore, an object of the present invention is to obtain a condensing pressure control device for a refrigerator that can be used at a low running cost by suppressing the required amount of compression work of the compressor.

[0004]

[Means for Solving the Problems]

 The condensing pressure control device of the refrigerator according to the present invention includes a compressor 1, an air-cooled condenser 2, a pressurizing pump 4, an expansion valve 5, and an evaporator 6, which circulate a refrigerant through a pipe 8 in order. Refrigeration cycle, a sensor 10 provided on the inlet side of the expansion valve 5 in the pipe 8 for detecting the condensation pressure P c, and a sensor 11 provided on the outlet side of the evaporator 6 for detecting the evaporation pressure Pe. When the condensing pressure Pc is less than or equal to the sum of the evaporating pressure Pe and the proper operating value Pv of the expansion valve 5 (Pc ≦ Pe + Pv) in response to the signals from both sensors 10 and 11, the condenser 2 is cooled. It is required to have a control unit 12 for stopping the rotation of the fan 9.

[0005]

[Action]

 The pressurizing pump 4 installed between the condenser 2 and the expansion valve 5 suppresses the pressure of the refrigerant discharged from the compressor 1 to reduce the required work of the compressor 1, and at the inlet side of the expansion valve 5, The condensing pressure Pc required for the expansion valve 5 to operate properly is secured to suppress the generation of flash gas when passing through the expansion valve 5. From the sensor 11 provided on the outlet side of the evaporator 6 in the pipe 8, a signal regarding the evaporation pressure Pe detected by the sensor 11 is output, and from the sensor 10 installed on the inlet side of the expansion valve 5 in the pipe 8, A signal relating to the condensation pressure Pc detected by the sensor 10 is transmitted to the control unit 12.

When the condensing pressure Pc is larger than the sum of the value Pv for the expansion valve 5 to operate properly and the evaporation pressure Pe (Pc> Pe + Pv), the control unit 12 rotates the fan 9. To cool the condenser 2. Then, when the condensing pressure Pc becomes a value equal to or less than the sum of the evaporation pressure Pe and the proper operating value Pv of the expansion valve 5 (Pc ≦ Pe + Pv), the rotation of the cooling fan 9 is stopped.

[0007]

[Effect of the device]

 The control device of the present invention having the control unit 12 and the sensors 10 and 11 cools the condenser 2 by rotating the fan 9 when the condensing pressure Pc becomes higher than necessary during operation of the refrigerator. Then, when the condensation pressure Pc becomes equal to or less than the sum of the evaporation pressure Pe and the proper operating value Pv of the expansion valve 5, the rotation of the fan 9 of the condenser 2 is stopped. As a result, the condensing pressure Pc is controlled on the basis of the evaporating pressure Pe and can be maintained near a low value within a practical range. Therefore, the required amount of compression work in the compressor 1 is reduced, and the amount of power consumption is further reduced. Also, it is possible to reduce the maintenance cost of the equipment.

[0008]

【Example】

 (First Embodiment) In Fig. 1, a refrigerator has a compressor 1, a condenser 2, a liquid receiver 3, a pressurizing pump 4, an expansion valve 5, an evaporator 6, and a liquid separator 7, which are sequentially connected by a pipe 8. It is equipped with a refrigeration cycle that circulates the refrigerant. The condenser 2 is an air-cooled type equipped with a cooling fan 9. The pressurizing pump 4 incorporated in the pipe 8 between the liquid receiver 3 and the expansion valve 5 is a magnet drive pump, and a high save pump manufactured by High Save Co. was used.

When R-502 is used as the refrigerant in the refrigerating apparatus having the above-described configuration, the refrigerant is compressed by the compressor 1 to become a high temperature and high pressure (83 ° C.-8.5 kg / cm ² ) gas, which is condensed. It is sent to the compactor 2. The pressure of the refrigerant at this time is lower than the value when passing through the expansion valve 5, and the load on the compressor 1 can be suppressed. The refrigerant is cooled to 17 ° C in the condenser 2 to become a high-pressure liquid, which is further pressurized to 0.6 kg / cm ^{2 by the} pressure pump 4 via the receiver 3 to 9.1 kg / cm ^2. Enter the expansion valve 5. The pressurizing pump 4 pressurizes the refrigerant by 0.6 kg / cm ² so that the refrigerant liquid is sent to the evaporator 6 while minimizing the generation of flash gas.

The refrigerant is depressurized to a constant low pressure of about 2.0 kg / cm ² when passing through the expansion valve 5, and then sent to the evaporator 6 to be vaporized. The vaporized refrigerant is returned to the compressor 1 again via the liquid separator 7 and circulates. The function of the expansion valve 5 is to allow the liquefied refrigerant to evaporate at a constant low pressure inside the evaporator 6 by adjusting the flow rate of the refrigerant under high pressure. Therefore, in order for the expansion valve 5 to operate properly, a constant pressure difference Pv (differential pressure between the condensation pressure Pc and the evaporation pressure Pe) before and after the expansion valve 5 is required. Further, the vaporization pressure Pe varies depending on the types of the refrigerant and the refrigerator, the use of the refrigerator and the use conditions thereof.

Therefore, a sensor 10 for detecting the condensation pressure Pc is installed on the inlet side of the expansion valve 5 in the pipe 8, and a sensor 11 for detecting the evaporation pressure Pe is provided on the outlet side of the evaporator 6, and the pipe is The pressure of the refrigerant in 8 is detected. Both sensors 10 and 11 send a signal relating to the detected pressure of the refrigerant to the control unit 12. The control unit 12 receives signals from both the sensors 10 and 11 and calculates the sum of the required pressure difference Pv (differential pressure between the condensation pressure Pc and the evaporation pressure Pe) before and after the expansion valve 5 and the evaporation pressure Pe. Based on this value, the fan 9 of the condenser 2 is controlled so as to obtain an appropriate condensing pressure Pc.

The expansion valve 5 is set to operate properly if the pressure difference between the condensation pressure and the evaporation pressure is, for example, 2 kg / cm ² or more. Therefore, the control unit 12 uses the signals from both the sensors 10 and 11 to calculate the condensing pressure Pc from the sum of the differential pressure Pv (approximately 2 kg / cm ² ) necessary to operate the expansion valve 5 properly and the evaporation pressure Pe. If it is larger, the fan 9 is rotated to cool the condenser 2 and the condensing pressure Pc is lowered. Then, the condensing pressure Pc is less than or equal to the sum of the proper operating pressure Pv of the expansion valve 5 and the evaporating pressure Pe, that is, when Pc ≦ Pv + Pe, the rotation of the cooling fan 9 is stopped to lower the condensing pressure Pc. Prevent overshoot.

As a result, the refrigerator can be sufficiently operated even when the condensation pressure Pc is about 4 kg / cm ² , and the required amount of compression work performed by the compressor 1 can be reduced. Therefore, it has become possible to reduce the amount of electric power used and the cost required for maintenance and management of the device.

[Brief description of drawings]

FIG. 1 is an explanatory diagram showing a concept of a refrigerator.

[Explanation of symbols]

 2 condenser 4 pressurizing pump 10 sensor 11 sensor 12 controller

Claims (1)

[Claims for utility model registration] [Claim 1] A compressor 1 for circulating a refrigerant through a pipe 8 in order, an air-cooled condenser 2, a pressure pump 4, an expansion valve 5,
A refrigeration cycle for circulation of a refrigerant provided with an evaporator 6, and a condensation pressure Pc provided on the inlet side of the expansion valve 5 in the pipe 8.
A sensor 10 for detecting the evaporation pressure and a sensor 11 provided on the outlet side of the evaporator 6 for detecting the evaporation pressure Pe, and signals from both sensors 10 and 11 to receive the condensation pressure Pc.
Is equal to or less than the sum of the evaporation pressure Pe and the appropriate operating value Pv of the expansion valve 5 (Pc ≦ Pe + Pv), the controller 12 for stopping the rotation of the cooling fan 9 for the condenser 2 is provided. Condensing pressure control device for refrigerator.