JPH058347U - Electronic expansion valve controller for refrigeration system - Google Patents

Abstract

(57) [Abstract] [Purpose] When the device is started up, it sends an appropriate amount of refrigerant to the evaporator to prevent liquid compression in the compressor. [Structure] A first temperature sensor 16 provided on the outlet side of a throttle valve 14 of a bypass flow path 15 so as to detect a refrigerant temperature, and an evaporator 1
The second temperature sensor 1 provided on the outlet side of 1 so as to detect the refrigerant temperature.
7, the third temperature sensor 1 provided inside the evaporator 11 to detect the temperature of the object to be cooled, and the temperature of the refrigerant on the outlet side of the evaporator 11 after starting the compressor arranged on the outlet side of the evaporator 11. Until the saturation temperature equivalent to the pressure on the outlet side is reached, the difference (S3-S2) between the detected value S3 by the third temperature sensor 1 and the detected value S2 by the second temperature sensor 17 is set within the set range. After reaching the saturation temperature equivalent to the pressure, the difference (S2) between the detected value S1 and the detected value S2 by the first temperature sensor 16 is detected.
It is formed by providing a controller 2 for adjusting the opening degree of the electronic expansion valve 12 so that −S1) is within the set range.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a control device for an electronic expansion valve for a refrigeration system, which adjusts a refrigerant flow rate in a shell-and-tube type evaporator.

[0002]

[Prior Art]

 Conventionally, as shown in FIG. 3, a shell-and-tube type evaporator 11 in which brine or water is caused to flow as a cooled object into a container and heat is exchanged with a refrigerant in a pipe for a refrigerant passage therein. There is a known refrigeration system which uses a closed loop of a refrigerant that continues from a condenser (not shown) to a compressor (not shown) via an electronic expansion valve 12 and an evaporator 11, and further from this compressor to the condenser. ing. Further, a bypass flow passage 15 is provided which connects the inlet side of the electronic expansion valve 12 to the outlet side of the evaporator 11 via the solenoid valve 13 and the throttle valve 14. Further, a first temperature sensor 16 capable of detecting the refrigerant temperature on the outlet side of the throttle valve 14 of the bypass flow path 15, a second temperature sensor 17 capable of detecting the refrigerant temperature on the outlet side of the evaporator 11, and the first temperature sensor There is provided a control device for the electronic expansion valve 12 including a controller 18 that adjusts the opening degree of the electronic expansion valve 12 based on the detection value S1 detected by 16 and the detection value S2 detected by the second temperature sensor 17. That is, in order to prevent liquid compression in the compressor, the controller 18 adjusts the opening degree of the electronic expansion valve 12 so that the detected value (S2-S1) is within the set range. Is sufficiently vaporized in the evaporator 11 and sent to the compressor.

As in the above device, the bypass flow path 15 is provided because the first temperature sensor 16 is attached to the inlet side of the evaporator 11 and the detected value (S2-S1) is within the set range in the same manner as above. This is because if the opening degree of the electronic expansion valve 12 is adjusted so that the above condition will occur, a problem will occur. That is, when the shell-and-tube type evaporator 11 is used, the pressure loss of the refrigerant in the evaporator 11 is large, and the refrigerant temperature at the location of the first temperature sensor 16 inevitably becomes high. The opening degree of the expansion valve 12 is adjusted to be small, and the amount of the refrigerant sent to the evaporator 11 becomes smaller than an appropriate value. Therefore, the bypass flow path 15 is provided so as not to be affected by the pressure loss, and the refrigerant temperature at the outlet side of the throttle valve 14 provided here is detected. Reference numeral 19 in FIG. 3 denotes an external pressure equalizing flow passage for applying a pressure at the outlet of the expansion valve to a diaphragm (not shown) in the electronic expansion valve 12.

[0004]

[Problems to be solved by the device]

 In the above conventional device, when the compressor is stopped, the solenoid valve 13 is also closed and the flow of the refrigerant to the bypass flow passage 15 is stopped, and as a result, the refrigerant temperature at the location of the first temperature sensor 16 rises. Then, the detected value S1 becomes normal temperature. As a result, the electronic expansion valve 12 is fully opened by a signal in the opening direction from the controller 18. When the compressor is restarted in this state, especially when the temperature of the object to be cooled flowing in the evaporator 11 is low, the refrigerant flows at once in the evaporator 11, and therefore the first temperature sensor Excessive supply of refrigerant to the evaporator 11 continues until the position of the sensor 16 is cooled and the difference between the detection ends (S2-S1) becomes appropriate. As a result, a large amount of refrigerant accumulates in the evaporator 11 until the detected value difference (S2-S1) reaches an appropriate state, and if the operation of the device is continued as it is, liquid compression occurs in the compressor, There is a problem that will damage the compressor. The present invention has been made to solve the above-mentioned conventional problems, and an appropriate amount of refrigerant is sent to the evaporator at the time of startup of the device to prevent the liquid compression in the compressor. It is intended to provide a control device for an expansion valve.

[0005]

[Means for Solving the Problems]

 In order to solve the above-mentioned problems, the present invention makes the inlet side of an electronic expansion valve communicate with the outlet side of a shell-and-tube type evaporator arranged on the outlet side of this electronic expansion valve via an on-off valve and a throttle valve. A first temperature sensor provided on the outlet side of the throttle valve of the bypass passage so as to detect the refrigerant temperature, a second temperature sensor provided on the outlet side of the evaporator so as to detect the refrigerant temperature, and the inside of the evaporator. After the start of the third temperature sensor provided to detect the temperature of the object to be cooled and the compressor arranged on the outlet side of the evaporator, the refrigerant temperature on the outlet side of the evaporator is the saturation temperature equivalent to the pressure on the outlet side. Until the difference (S3-S2) between the value S3 detected by the third temperature sensor and the value S2 detected by the second temperature sensor is within the set range, and the saturation temperature equivalent to the pressure is reached. After reaching, the detected value S1 by the first temperature sensor becomes The difference between the serial detection value S2 (S2-S1) is formed by providing an adjustment gauge for adjusting the opening degree of the electronic expansion valve so that within a set range.

[0006]

[Action]

 With the configuration as described above, the opening degree of the electronic expansion valve becomes appropriate while the device is stopped, and the supply amount of the refrigerant to the evaporator at the next startup of the device is kept at a proper value. become.

[0007]

【Example】

 Next, an embodiment of the present invention will be described with reference to the drawings. 1 and 2 show a refrigerating apparatus to which the control device according to the present invention is applied, and portions common to the refrigerating apparatus shown in FIG. In the present embodiment, the first temperature sensor 16 and the second temperature sensor 17 are provided as in the apparatus of FIG. 3, and the third temperature sensor 1 is provided in the evaporator 11 so that the temperature of the cooled object can be detected. is there. Then, by the controller 2, the value S1 detected by the first temperature sensor 16 is set to a value corresponding to the temperature of the object to be cooled in the evaporator 11, that is, the value S3 detected by the third temperature sensor 1 when the apparatus is started. Also, after the value S2 detected by the second temperature sensor 17 reaches the saturation temperature equivalent to the evaporator outlet pressure, the electronic value is adjusted so that it becomes a value commensurate with the detection value S1 as in the device shown in FIG. The opening degree of the expansion valve 12 is adjusted.

Specifically, as shown in FIG. 2 showing the control circuit of the controller 2, when the device is stopped, the contact point m is in a state in which the third temperature sensor 1 side is closed. The detection values S2 and S3 are input to the control circuit section 2a therein. When the device is activated, the contact MX is closed and the timer T starts operating. Until the timer T counts up, the contact m maintains the above state, and the opening degree signal is sent from the control circuit unit 2a to the electronic expansion valve 12 so that the difference (S3-S2) in the detected values is within the set range. Is output and the opening degree of the electronic expansion valve 12 is adjusted. On the other hand, when the timer T counts up, the contact T 3 is closed and the relay m is excited, the contact m is switched to the first temperature sensor 16 side, and the control circuit 2a changes to the detection value S3 instead of the detection value S3. Will be entered. Then, the opening degree signal is output from the control circuit unit 2a to the electronic expansion valve 12 so that the difference (S1-S2) between the detected values is within the set range, and the opening degree of the electronic expansion valve 12 is adjusted. .

In this way, after the apparatus is started, until the detected value S2 reaches the saturation temperature equivalent to the outlet pressure of the evaporator 11, the location of the first temperature sensor 16 becomes a temperature commensurate with the temperature of the object to be cooled. As described above, by adjusting the opening degree of the electronic expansion valve 12, and then adjusting the opening degree of the electronic expansion valve 12 based on the detected values S1 and S2, the refrigerant supply amount to the evaporator 11 is made appropriate, The liquid is not compressed by the compressor. In the above embodiment, the timer T is used to switch from the state until the detected value S2 reaches the saturation temperature equivalent to the outlet pressure of the evaporator 11 to the subsequent state. Other than this, for example, instead of the timer T, the second temperature sensor 17 directly detects that the saturation temperature corresponding to the outlet pressure of the evaporator 11 is reached, and the contact point m is switched. It may be formed.

[0010]

[Effect of the device]

 As is clear from the above description, according to the present invention, an on-off valve and a throttle valve are provided on the outlet side of a shell-and-tube type evaporator in which the inlet side of the electronic expansion valve is arranged on the outlet side of the electron expansion valve. Temperature sensor provided on the outlet side of the throttle valve for detecting the refrigerant temperature, the second temperature sensor provided on the outlet side of the evaporator for detecting the refrigerant temperature, and the evaporator After the start of the third temperature sensor, which is provided in the inside of the evaporator to detect the temperature of the object to be cooled, and the compressor arranged on the outlet side of the evaporator, the temperature of the cooling medium on the outlet side of the evaporator is the pressure on the outlet side. Until the equivalent saturation temperature is reached, the difference (S3-S2) between the detection value S3 detected by the third temperature sensor and the detection value S2 detected by the second temperature sensor should be within the set range. After reaching the saturation temperature equivalent to the pressure, the first temperature sensor detects Value S1 and the difference between the detection value S2 (S2-S1) is is formed by providing an adjustment gauge for adjusting the opening degree of the electronic expansion valve so that within a set range. For this reason, the opening of the electronic expansion valve becomes appropriate while the device is stopped, and the amount of refrigerant supplied to the evaporator at the next startup of the device maintains an appropriate value. The refrigerant is sent to the evaporator, and it is possible to prevent liquid compression in the compressor.

[Brief description of drawings]

FIG. 1 is a configuration diagram showing a part of a refrigerating apparatus to which a control device for an electronic expansion valve according to the present invention is applied.

FIG. 2 is a circuit diagram of a controller in the device shown in FIG.

FIG. 3 is a configuration diagram showing a part of a refrigeration system to which a control device for a conventional electronic expansion valve is applied.

[Explanation of symbols]

 1 Third Temperature Sensor 2 Controller 11 Evaporator 12 Electronic Expansion Valve 14 Throttle Valve 15 Bypass Flow Path 16 First Temperature Sensor 17 Second Temperature Sensor

Claims (1)

[Claims for utility model registration] 1. The inlet side of the electronic expansion valve is communicated with the outlet side of the shell-and-tube type evaporator arranged on the outlet side of the electronic expansion valve through an on-off valve and a throttle valve. A first temperature sensor provided on the outlet side of the throttle valve of the bypass passage so as to detect the refrigerant temperature, a second temperature sensor provided on the outlet side of the evaporator so as to detect the refrigerant temperature, and the inside of the evaporator. After starting the third temperature sensor that can detect the temperature of the object to be cooled and the compressor arranged on the outlet side of the evaporator, the refrigerant temperature on the outlet side of the evaporator becomes the saturation temperature equivalent to the pressure on the outlet side. Until it reaches, the difference (S3-S2) between the value S3 detected by the third temperature sensor and the value S2 detected by the second temperature sensor is within the set range, and the saturation temperature equivalent to the pressure is reached. After that, the value S1 detected by the first temperature sensor and A control of the electronic expansion valve for a refrigeration system, which is provided with a controller for adjusting the opening degree of the electronic expansion valve such that the difference (S2-S1) from the detected value S2 is within a set range. apparatus.