JPH0777362A - Method and apparatus for controlling temperature of freezer - Google Patents

Abstract

PURPOSE:To improve an evaporating efficiency and prevent an occurrence of liquid back by a method wherein a superheating degree adjusting part is selected in the case that a temperature of cooled part is higher than a set temperature at a selecting part, and a liquid injection valve is adjusted only by an operating amount calculated at a calculation part through an operating part. CONSTITUTION:An evaporator in an air cooler is comprised of a temperature sensor 9 for sensing a temperature of cooled part 7; a temperature sensor 10 for sensing a temperature of refrigerant gas within a refrigerant gas outlet pipe 8; and a pressure sensor 11 for sensing an evaporating pressure. Each of the sensor signals is inputted to a temperature adjusting part 12 and a superheating degree adjusting part 13 within the controller 18. At the temperature adjusting part 12, an operating amount in which a liquid injection valve 5 is adjusted through an operating part 15 and another operating amount in which an evaporating pressure adjusting valve 14 arranged at a refrigerant gas outlet pipe 8 is adjusted through an operating part 16 are calculated and concurrently an operating amount in which the liquid injection valve 5 is adjusted at the superheating degree adjusting part 13 is also calculated. However, in the case that a temperature of the cooled part 7 is higher than a set temperature, the superheating degree adjusting part 13 may be selected at a selecting part 17 and operated.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is equipped with a selection section for selecting a temperature control section and a superheat degree control section in a refrigerating apparatus according to the temperature of a cooled section cooled by an evaporator or an air cooler and its set temperature. The present invention relates to a temperature control method for a refrigerating apparatus and a device therefor which does not cause liquid back.

[0002]

2. Description of the Related Art Conventionally, as a temperature control method and apparatus for this type of refrigerating apparatus, Japanese Utility Model Publication No. 56-12761 and Japanese Patent Publication No.
No. 39710 is available.

In Japanese Utility Model Application Laid-Open No. 56-12761, the temperature of the cooled portion of the evaporator is input to the temperature controller, and the temperature and pressure of the refrigerant gas at the refrigerant gas outlet pipe of the evaporator are input to the superheat controller. ing.

Then, the set value of the superheat degree of the superheat controller is designated by the output of the temperature controller, and the flow control valve provided in the refrigerant liquid supply pipe of the evaporator is operated by the superheat controller by the superheat controller. Adjustment is made so that the measured degree of superheat and the set degree of superheat are equal.

In Japanese Patent Publication No. 2-39710, a temperature controller for inputting the temperature of the cooled portion of the evaporator and a superheat controller for inputting the temperature and pressure of the refrigerant gas in the refrigerant gas outlet pipe of the evaporator are also provided. To provide.

Then, the output signals of the temperature controller and the superheat controller are input to the minimum value selection circuit, and the opening of the flow rate adjusting valve provided in the refrigerant liquid supply pipe of the evaporator is adjusted by the smaller output signal. To do.

[0007]

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention
In JP 2761, the opening of a flow rate adjusting valve provided in a refrigerant liquid supply pipe of an evaporator is adjusted by an output signal of a temperature controller to keep the temperature of a cooled portion constant.

However, when the temperature of the cooled portion suddenly rises or falls due to a sudden change in load, the set value of the superheat degree is changed, and the flow rate adjusting valve is adjusted so that the set superheat degree is measured and measured by the superheat degree controller. Therefore, it was not possible to keep up with the sudden change in the load, the temperature of the cooled part could not be kept constant, and the phenomenon of liquid back was caused.

In Japanese Patent Publication No. 2-39710, the output signals of the superheat controller of the refrigerant gas outlet pipe and the temperature controller of the cooled part are compared by a minimum value selection circuit and the smaller output signal is selected. To do.

By controlling the flow rate of the refrigerant and the opening degree of the flow rate control valve for depressurizing by this output signal, the temperature of the cooled part is kept constant by the output signal of the temperature controller in the normal cooling process. Hold.

When the temperature of the cooled portion suddenly rises, the output signal of the temperature controller is selected to greatly adjust the opening degree of the valve to increase the refrigerant liquid supply amount.

Further, when the degree of superheat of the refrigerant gas becomes equal to or lower than the set degree of superheat, the opening degree of the valve is adjusted to be small by the output signal of the degree of superheat controller to reduce the refrigerant liquid supply amount and prevent the liquid back. There is.

However, since the valve is provided in the refrigerant liquid supply pipe of the evaporator, if the degree of superheat further decreases, the refrigerant liquid supplied to the evaporator cannot be completely evaporated, the evaporation efficiency is low, and there is a risk of causing liquid back. there were.

An object of the present invention is to provide a temperature control method for a refrigerating apparatus which has a high evaporation efficiency and does not cause a liquid bag, and an apparatus therefor.

[0015]

In order to achieve the above object, the present invention detects a temperature of a refrigerant gas in a refrigerant gas outlet pipe and a temperature sensor for detecting a temperature of a cooled portion of an evaporator or an air cooler as in the prior art. A temperature sensor and a pressure sensor for detecting the evaporation pressure are provided.

The detected values from the respective sensors are input, the operation amount for adjusting the liquid injection valve is calculated via the operation section A, and the evaporation pressure interposed on the compressor suction side of the refrigerant gas outlet pipe via the operation section B. A temperature control unit with a built-in superheat controller is calculated by calculating the operation amount to adjust the adjusting valve.

Further, by inputting the detected values from the respective sensors,
A superheat degree adjusting section for calculating an operation amount for adjusting the liquid injection valve via the operation section A is provided.

A temperature setting unit is provided, and a selection unit for selecting the temperature control unit or the superheat control unit is provided according to the set temperature and the temperature of the cooled unit from the temperature sensor of the evaporator or air cooler.

Therefore, when the temperature of the cooled portion is higher than the set temperature of the selecting portion, the superheat degree adjusting portion calculates the operation amount and operates the liquid injection valve.

On the contrary, when the temperature of the cooled portion is equal to or lower than the set temperature of the selecting portion, the operation amount is calculated by the temperature adjusting portion, and the liquid injection valve and the evaporation pressure adjusting valve are operated through the operating portions A and B. Then
The temperature of the cooled part is brought close to the set temperature of the selection part.

Further, the heat load changes abruptly, the temperature in the refrigerant gas outlet pipe falls below the set temperature of the selection section, and further falls below the set superheat degree preset in the superheat controller incorporated in the temperature control section. In this case, the superheat controller operates, the liquid injection valve is closed via the operation unit A, the supply of the refrigerant liquid is stopped, and the liquid back phenomenon (wet compression) to the compressor is prevented.

[0022]

According to the temperature of the cooled portion 7 and the set value set in the selection portion 17, either the refrigerant gas superheat degree adjusting portion 13 or the temperature adjusting portion 12 of the cooled portion 7 is selected.

That is, when the temperature of the cooled portion 7 is higher than the set value, the superheat degree adjusting portion 13 is selected, the operation amount of the liquid injection valve 5 is calculated by the superheat degree adjusting portion 13, and the liquid is supplied via the operation portion A. The injection valve 5 is adjusted.

When the temperature of the cooled portion 7 becomes equal to or lower than the set value, the temperature adjusting portion 12 is selected, the operation amount of the liquid injection valve 5 is calculated by the temperature adjusting portion 12, and the liquid is supplied via the operating portion A. The injection valve 5 is adjusted.

Further, when the temperature of the refrigerant gas in the refrigerant gas outlet pipe 8 of the evaporator or the air cooler 1 becomes lower than the set superheat degree of the superheat controller incorporated in the temperature control section 12 due to a sudden change in load or the like, The liquid injection valve 5 is closed via the operation unit A.

Further, an evaporating pressure adjusting valve 14 is connected to the temperature adjusting section 12 via the operating section B on the side of the inlet of the compressor 2 of the refrigerant gas outlet pipe 8 of the evaporator or air cooler 1. When the temperature control unit 12 is selected due to a sudden change in the load or the like and the liquid back occurs, the evaporating pressure adjusting valve 14 lowers the evaporating pressure and operates the operation unit B so as to increase the capacity of the evaporator or the air cooler 1. Then adjust the evaporation pressure.

On the contrary, when the temperature of the refrigerant gas in the refrigerant gas outlet pipe of the evaporator is stable near the temperature of the cooled portion,
Assuming that the evaporator or air cooler 1 has a margin, adjustment is made to increase the evaporation pressure.

[0028]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A detailed description will be given of the accompanying drawings showing an example of the embodiment of the present invention.

FIG. 1 is a piping / wiring diagram showing an outline of the device of the present invention.

Reference numeral 1 is an evaporator or air cooler, which condenses a high-temperature high-pressure refrigerant gas discharged from the compressor 2 in a condenser 3,
It is stored as a high-pressure liquid in the liquid receiver 4 and is supplied as a low-temperature low-pressure liquid by the liquid injection valve 5 from the refrigerant liquid supply pipe 6 to exchange heat with air or the like to cool the cooled portion 7 and then from the refrigerant gas outlet pipe 8. The refrigerating apparatus is configured by a refrigerating cycle in which the refrigerant gas returns to the compressor 2.

A temperature sensor 9 is provided in the cooled portion 7 of the evaporator or air cooler 1 and detects the temperature of the cooled portion 7.

A temperature sensor 10 is provided in the refrigerant gas outlet pipe 8 and detects the temperature of the refrigerant gas in the outlet pipe 8.

Reference numeral 11 denotes a pressure sensor provided in the refrigerant gas outlet pipe 8, which is the evaporation pressure (saturation temperature) of the refrigerant gas in the outlet pipe 8.
Is to detect.

Reference numeral 12 denotes a temperature control section connected to the respective sensors 9, 10, 11 and a calculation section for calculating the operation amount of the liquid injection valve 5 and an evaporation pressure control valve 14 which will be described later, and the temperature sensor 1.
0, which is connected to the pressure sensor 11 and has a built-in superheat controller having a superheat setting unit.

Reference numeral 13 is a superheat degree adjusting section connected to each of the sensors 9, 10 and 11, and has a built-in calculating section for calculating the operation amount of the liquid injection valve 5.

Reference numeral 14 denotes an evaporation pressure adjusting valve which is provided on the refrigerant gas outlet pipe 8 on the suction side of the compressor 2 and adjusts the evaporation pressure of the refrigerant gas in the evaporator or the air cooler 1 to adjust the evaporation pressure of the evaporator or the air cooler 1. Adjust the evaporation efficiency.

Reference numeral 15 is an operating portion A for operating the liquid injection valve 5,
It is connected to the temperature control unit 12 and the superheat control unit 13, receives signals from the arithmetic units of the temperature control unit 12 and the superheat control unit 13,
The liquid injection valve 5 is opened and closed by closing the liquid injection valve 5 by each operation amount.

Reference numeral 16 denotes an operating section B for operating the evaporation pressure adjusting valve 14, which is connected to the temperature adjusting section 12 and receives a signal from the calculating section of the temperature adjusting section 12 to open or close the evaporation pressure adjusting valve 14 by the operation amount. Adjust.

Reference numeral 17 denotes a selection unit, which has a built-in temperature setting unit, is connected to the temperature sensor 9 and the temperature and superheat degree adjusting units 12 and 13, and has a preset temperature and temperature sensor 9 preset by the temperature setting unit.
Each of the adjusting parts 12 and 13 is selected based on the temperature of the part to be cooled.

That is, the cooled portion 7 detected by the temperature sensor 9
If the temperature is higher than the set temperature, the superheat control unit 1
3 is selected, and the temperature controller 12 is selected when the temperature becomes equal to or lower than the set temperature.

When the temperature control section 12 is selected and the temperature of the cooled section 7 falls below the set superheat degree of the superheat degree controller built in the temperature control section 12, the liquid injection valve 5 is closed, The liquid back to the compressor 2 is prevented.

Reference numeral 18 denotes a controller, which is a selection unit 17, operation units A, B (15, 1) of the temperature control unit 12, the superheat degree control unit 13, the liquid injection valve 5 and the evaporation pressure control valve 14 which are selected.
It consists of 6).

[0043]

The present invention has the above-described structure, and when the temperature of the cooled portion 7 is higher than the set temperature of the selection portion 17, the superheat degree adjusting portion 13 is selected and the operation portion A (15) is used. Since the liquid injection valve 5 is adjusted by the operation amount calculated by the calculation unit,
The temperature of the cooled part 7 can be brought close to the set temperature of the selection part 17.

When the temperature of the cooled portion 7 becomes lower than the set temperature of the selecting portion 17, the temperature adjusting portion 12 is selected,
Since the liquid injection valve 5 is closed via the operation parts A and B (15, 16) and the evaporation pressure adjusting valve 14 is adjusted by the operation amount calculated by the calculating part, the temperature of the cooled part 7 is controlled by the selecting part 17. It can approach the set temperature.

Further, even when the temperature of the cooled portion 7 becomes equal to or lower than the set temperature of the selection portion 17 and falls below the superheat degree set by the superheat degree controller to cause liquid back, the evaporation pressure adjusting valve 14
Can be adjusted to increase the evaporation capacity of the evaporator, and wet compression in the compressor 2 can be prevented in advance.

[Brief description of drawings]

FIG. 1 is a piping / wiring diagram showing an outline of a temperature control device for a refrigeration system of the present invention.

[Explanation of symbols]

 1 Evaporator or Air Cooler 2 Compressor 3 Condenser 4 Liquid Receiver 5 Liquid Injection Valve 6 Refrigerant Liquid Supply Pipe 7 Cooled Part 8 Refrigerant Gas Outlet Pipe 9, 10 Temperature Sensor 11 Pressure Sensor 12 Temperature Adjusting Part 13 Superheat Adjusting Part 14 Evaporation Pressure Control Valve 15 Operation Unit A 16 Operation Unit B 17 Selection Unit 18 Controller

Claims (2)

[Claims] 1. A temperature control unit for inputting a temperature of a cooled portion cooled by an evaporator or an air cooler in a refrigeration system and a temperature and a pressure in a refrigerant gas outlet pipe of the evaporator or the air cooler, and a temperature of the cooled portion. The temperature and pressure of the evaporator or the air cooler are input to input a signal from the superheat degree adjusting section for adjusting the degree of superheat. From the temperature adjusting section, a liquid injection valve interposed in the refrigerant liquid supply pipe via the operation section A and , Operation unit B
The evaporation pressure adjusting valve interposed in the refrigerant gas outlet pipe is adjusted, and the liquid injection valve is adjusted from the superheat adjusting unit via the operation unit A. The selecting unit is selected according to the temperature of the cooling unit and the set temperature. Select the temperature control part and superheat control part with, and if the temperature of the cooled part is higher than the set temperature of the selected part, calculate the operation amount with the superheat control part, operate the liquid injection valve, and cool When the temperature of the part is less than or equal to the set temperature of the selection part, the operation amount is calculated by the temperature adjustment part, and the liquid injection valve and the evaporation pressure adjustment valve are operated via the operation parts A and B, both of which are to be cooled parts. The temperature of the selected portion is brought close to the set temperature, the heat load changes abruptly, the temperature in the refrigerant gas outlet pipe becomes equal to or lower than the set temperature of the selected portion, and the superheat controller incorporated in the temperature adjusting portion previously When the temperature falls below the set superheat level, the superheat controller operates and the Temperature control method of the refrigeration apparatus, characterized in that closing the liquid injection valve, to prevent liquid back phenomenon of the compressor (the wet compression) through. 2. A refrigeration system in which a refrigerant gas discharged from a compressor is condensed in a condenser and stored in a liquid receiver as a high-pressure liquid, reduced in pressure by a liquid injection valve to become a low-temperature low-pressure liquid and supplied to an evaporator or an air cooler. In the device, a temperature sensor that detects the temperature of the cooled part of the evaporator or air cooler is provided, and a temperature sensor that detects the temperature of the refrigerant gas in the refrigerant gas outlet pipe of the evaporator or air cooler and a pressure that detects the evaporation pressure of the refrigerant gas A sensor is provided, and the detection value from each sensor is input, and a vapor pressure adjusting valve interposed on the compressor suction side of the refrigerant gas outlet pipe via the operation portion A and the liquid injection valve of the refrigerant liquid supply pipe and the operation portion B. The temperature control part which calculates the operation amount which adjusts and which has the superheat degree controller which has the superheat degree setting part is provided, inputs the detected value from each said sensor, and adjusts a liquid injection valve via the operation part A. Calculate the operation amount A superheat control section is provided and a temperature setting section is provided. The temperature control section and superheat control section are selected according to the set temperature and the temperature of the cooled section from the temperature sensor that detects the temperature of the cooled section of the evaporator or air cooler. A temperature control device for a refrigerating apparatus, comprising: