JP2769423B2 - Refrigeration device temperature control method and device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

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

[0002]

2. Description of the Related Art Conventionally, a temperature control method and apparatus of this type of refrigeration apparatus have been disclosed in Japanese Utility Model Publication No. Sho 56-12762,
39710 and the like.

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

The set value of the degree of superheat of the superheat controller is designated by the output of the temperature controller, and the superheat controller controls a flow control valve provided in the refrigerant liquid supply pipe of the evaporator by the superheat controller. Is adjusted so that the measured superheat degree becomes equal to the set superheat degree.

In Japanese Patent Publication No. 39710/1990, similarly, a temperature controller for inputting the temperature of the portion to be cooled of the evaporator and a superheat controller for inputting the temperature and pressure of the refrigerant gas at the refrigerant gas outlet pipe of the evaporator. Is provided.

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

[0007]

Problems to be Solved by the Invention
In Japanese Patent No. 2761, the opening of a flow control 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, if the temperature of the part to be cooled suddenly rises or falls due to a sudden change in load or the like, the set value of the degree of superheat is changed, measured by a superheat degree controller, and the flow regulating valve is adjusted so that the set degree of superheat becomes equal. Therefore, it was not possible to follow a sudden change in the load, and the temperature of the cooled part could not be kept constant, or the phenomenon of liquid back occurred.

In Japanese Patent Publication No. 39970/1990, the output signal of the superheat controller of the refrigerant gas outlet pipe and the temperature controller of the part to be cooled are compared by a minimum value selection circuit, and the smaller output signal is selected. I do.

By controlling the flow rate of the refrigerant and the opening of the flow control valve for reducing the pressure in accordance with the output signal, the temperature of the portion to be cooled is kept constant by the output signal of the temperature controller in the normal cooling process. Hold.

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

Further, when the degree of superheat of the refrigerant gas falls below the set degree of superheat, the opening degree of the valve is adjusted to be small by the output signal of the superheat degree controller to reduce the refrigerant liquid supply amount and prevent liquid back. I have.

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 completely evaporate, so that there is a risk that the evaporation efficiency is low and a liquid back occurs. there were.

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

[0015]

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

A detection value from each of the sensors is input, an operation amount for adjusting the liquid injection valve is calculated via an operation section A, and an evaporating pressure interposed on a compressor suction side of a refrigerant gas outlet pipe via an operation section B. An operation amount for adjusting the control valve is calculated, and a temperature control unit having a built-in superheat controller is provided.

Further, a detection value from each of the sensors is inputted,
A superheat degree adjustment unit for calculating an operation amount for adjusting the liquid injection valve via the operation unit A is provided.

There is provided a temperature setting section, and a selection section for selecting a temperature adjustment section and a superheat degree adjustment section based on the set temperature and the temperature of the section to be cooled from the temperature sensor of the evaporator or the air cooler.

If the temperature of the portion to be cooled is higher than the set temperature of the selection unit, the operation amount is calculated by the superheat degree adjustment unit, and the liquid injection valve is operated.

Conversely, when the temperature of the portion to be cooled is equal to or lower than the set temperature of the selection unit, the operation amount is calculated by the temperature adjustment unit, and the liquid injection valve and the evaporation pressure adjustment valve are operated via the operation units A and B. And
The temperature of the part to be cooled is brought closer to the set temperature of the selection part.

Further, the heat load changes abruptly, and 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 degree controller built in the temperature control section. In this case, the superheat controller operates and closes the liquid injection valve via the operation unit A to stop the supply of the refrigerant liquid to prevent the liquid back phenomenon (wet compression) to the compressor.

[0022]

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

That is, when the temperature of the portion to be cooled 7 is higher than the set value, the superheat degree adjustment section 13 is selected, the operation amount of the liquid injection valve 5 is calculated by the superheat degree adjustment section 13, The injection valve 5 is adjusted.

When the temperature of the part to be cooled 7 becomes lower than the set value, the temperature control part 12 is selected, the operation amount of the liquid injection valve 5 is calculated by the temperature control part 12, 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 degree controller built in the temperature control section 12 due to a sudden change of the load or the like, The liquid injection valve 5 is closed via the operation section A.

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

Conversely, when the temperature of the refrigerant gas at the refrigerant gas outlet pipe of the evaporator is stable around the temperature of the portion to be cooled,
Assuming that the evaporator or the air cooler 1 has a margin, adjustment is made to increase the evaporation pressure.

[0028]

BRIEF DESCRIPTION OF THE DRAWINGS The accompanying drawings, which show an embodiment of the present invention, will be described in detail.

FIG. 1 is a piping and wiring diagram schematically showing the apparatus of the present invention.

Reference numeral 1 denotes an evaporator or an air cooler, which condenses a high-temperature and high-pressure refrigerant gas discharged from a compressor 2 in a condenser 3.
The high-pressure liquid is stored in the liquid receiver 4, supplied as a low-temperature low-pressure liquid from the refrigerant liquid supply pipe 6 by the liquid injection valve 5, exchanges heat with air or the like, cools the portion to be cooled 7, and is supplied from the refrigerant gas outlet pipe 8. This constitutes a refrigeration system including a refrigeration cycle in which refrigerant gas returns to the compressor 2.

Reference numeral 9 denotes a temperature sensor which is provided in the cooled portion 7 of the evaporator or the air cooler 1 and detects the temperature of the cooled portion 7.

Reference numeral 10 denotes a temperature sensor provided in the refrigerant gas outlet pipe 8 for detecting 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 an evaporation pressure (saturation temperature) of the refrigerant gas in the outlet pipe 8.
Is to be detected.

Numeral 12 denotes a temperature controller connected to each of the sensors 9, 10, 11; a calculator for calculating the operation amounts of the liquid injection valve 5 and an evaporating pressure control valve 14, which will be described later;
0, which is connected to the pressure sensor 11 and has a built-in superheat degree controller having a superheat degree setting section.

Reference numeral 13 denotes a superheat degree adjustment unit connected to the sensors 9, 10, and 11, which has a built-in operation unit for calculating the operation amount of the liquid injection valve 5.

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

Reference numeral 15 denotes an operation unit A for operating the liquid injection valve 5,
Connected to the temperature control unit 12 and the superheat control unit 13 and receive signals from the calculation units of the temperature control unit 12 and the superheat control unit 13;
The opening and closing of the liquid injection valve 5 is adjusted by each operation amount including the closing.

Reference numeral 16 denotes an operation section B for operating the evaporating pressure adjusting valve 14, which is connected to the temperature adjusting section 12, receives a signal from the calculating section of the temperature adjusting section 12, and opens and closes the evaporating pressure adjusting valve 14 by the operated 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 adjustment units 12 and 13, and has a preset temperature and temperature sensor 9 preset by the temperature setting unit.
Each of the adjusting units 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 degree adjusting unit 1
3 is selected, and when the temperature falls below the set temperature, the temperature controller 12 is selected.

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

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

[0043]

According to the present invention, when the temperature of the cooled part 7 is higher than the set temperature of the selecting part 17, the superheat degree adjusting part 13 is selected, and the superheat degree adjusting part 13 is selected via the operating part A (15). To adjust the liquid injection valve 5 by the operation amount calculated by the calculation unit,
The temperature of the part to be cooled 7 can be brought close to the temperature set by the selecting part 17.

When the temperature of the portion 7 to be cooled becomes lower than the temperature set by the selector 17, the temperature controller 12 is selected.
The liquid injection valve 5 is closed via the operation units A and B (15, 16), and the evaporation pressure adjusting valve 14 is adjusted by the operation amount calculated by the operation unit. It can approach the set temperature.

Further, even when the temperature of the part to be cooled 7 becomes equal to or lower than the temperature set by the selector 17 and drops below the degree of superheat set by the superheat controller, the evaporation pressure adjusting valve 14 is provided.
Can be adjusted to increase the evaporation capacity of the evaporator, and wet compression in the compressor 2 can be prevented.

[Brief description of the drawings]

FIG. 1 is a piping and wiring diagram schematically showing a temperature control device of a refrigeration apparatus of the present invention.

[Explanation of symbols]

 DESCRIPTION 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 control part 13 Superheat degree control part 14 Evaporation pressure regulating valve 15 Operation section A 16 Operation section B 17 Selection section 18 Controller

Claims (2)

(57) [Claims] A temperature controller for inputting a temperature of a portion to be cooled by an evaporator or an air cooler and a temperature and a pressure in a refrigerant gas outlet pipe of the evaporator or the air cooler; The temperature and pressure of the evaporator or the air cooler are inputted, and a signal from the superheat degree adjusting section for adjusting the degree of superheat is inputted.From the temperature adjusting section, a liquid injection valve interposed in the refrigerant liquid supply pipe via the operation section A is provided. , Operation unit B
The evaporating pressure adjusting valve interposed in the refrigerant gas outlet pipe is adjusted via the above, and the liquid injection valve is adjusted from the superheating degree adjusting unit via the operating unit A, and the selecting unit is selected according to the temperature of the cooling unit and a set temperature. Select the temperature control unit and the superheat control unit, and if the temperature of the cooled unit is higher than the set temperature of the selection unit, calculate the operation amount in the superheat control unit, operate the liquid injection valve, and When the temperature of the section is equal to or lower than the set temperature of the selection section, the operation amount is calculated by the temperature control section, the liquid injection valve and the evaporation pressure control valve are operated via the operation sections A and B, and both of the sections to be cooled Approaching the set temperature of the selection unit, the heat load changes rapidly, the temperature in the refrigerant gas outlet pipe becomes equal to or lower than the set temperature of the selection unit, and furthermore, the superheat degree controller built in the temperature control unit is used in advance. When the superheat degree falls below the set superheat degree, the superheat controller operates and the operation 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, stored as a high-pressure liquid in a receiver, and decompressed by a liquid injection valve to become a low-temperature low-pressure liquid and supplied to an evaporator or an air cooler. In the apparatus, a temperature sensor for detecting a temperature of a cooled portion of the evaporator or the air cooler is provided, and a temperature sensor for detecting a temperature of the refrigerant gas in a refrigerant gas outlet pipe of the evaporator or the air cooler and a pressure for detecting an evaporation pressure of the refrigerant gas. A sensor is provided, a detection value from each of the sensors is input, and a liquid injection valve of a refrigerant liquid supply pipe passes through an operation section A and an evaporating pressure regulating valve interposed on a compressor suction side of a refrigerant gas outlet pipe passes through an operation section B. Calculate the amount of operation to adjust the temperature, provide a temperature control unit with a built-in superheat controller having a superheat setting unit, input a detection value from each of the sensors, and adjust the liquid injection valve via the operation unit A. Calculate MV A superheat control unit is provided, and a temperature setting unit is provided.The temperature control unit and the superheat control unit are selected based on the set temperature and the temperature of the cooled unit from the temperature sensor that detects the temperature of the cooled unit of the evaporator or the air cooler. A temperature control device for a refrigeration system, comprising: