JP2923109B2 - Refrigeration cycle control method for constant temperature and humidity apparatus, and constant temperature and humidity apparatus - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electronic proportional control valve provided in the middle of a bypass circuit connecting a condenser outlet and a compressor suction side. by Gosuru optimally variable Hensei to match constantly to the refrigerant gas temperature, the refrigeration cycle control of the constant temperature and humidity apparatus sudden change has to be prevented in the heating operation and cooling capability of the compressor refrigerant discharge gas temperature rise More specifically, the present invention relates to a constant temperature and humidity apparatus to which such a refrigeration cycle control method is applied.

[0002]

Heretofore, as a countermeasure against a temperature rise of the compressor discharge refrigerant gas in the refrigeration cycle, a method of Ru allowed increasing the aperture of the refrigeration cycle pressure reducing mechanism is generally known. In the case of this method, the low-pressure side pressure is reduced by increasing the throttle, and the refrigerant circulation amount is reduced and the load on the compressor is reduced. As a result, the temperature rise of the discharged refrigerant gas is suppressed. It has become. In addition to the above method, a liquid bypass circuit is generally provided between a condenser outlet and a compressor suction side. The liquid bypass circuit is provided with a capillary tube or a temperature expansion valve, and the liquid bypass circuit is opened and closed by an electromagnetic valve whose opening and closing operation is controlled by a discharge gas temperature sensor, and the liquefied refrigerant is compressed from the condenser outlet. It is intended to bypass the machine suction side. By reducing the heating degree of the compressor suction gas temperature by bypassing the liquefied refrigerant, the compressor discharge refrigerant gas temperature is confined within an allowable range as a result. As a specific technique for suppressing a rise in the temperature of the refrigerant gas discharged from the compressor, for example, a technique described in Japanese Utility Model Laid-Open No. 63-120050 is known. In this case, a temperature type expansion valve for a boiling point higher than the boiling point of the refrigerant is provided in the middle of the liquid bypass circuit connecting the outlet of the condenser and the suction side of the compressor.

[0003]

By the way, in the constant temperature and humidity apparatus, the operable ambient temperature (condensation temperature) for controlling the temperature and humidity in the space area closed by the heat insulating layer, that is, the test room. The allowable upper and lower limit temperature is determined by the usage limit of the refrigerator, but if the temperature of the refrigerant gas discharged from the compressor rises due to the high ambient temperature, it is necessary to prevent the compressor from burning. It is necessary to suppress the temperature rise. However, until now, the temperature rise cannot be suppressed by making the temperature good. By passing the liquefied refrigerant from the condenser outlet to the compressor suction side by the liquid bypass circuit and the solenoid valve provided between the condenser outlet and the compressor suction side, the temperature rise is suppressed as a result. However, since the solenoid valve is opened and the temperature rise is suppressed only when the temperature rise exceeds a certain level, the cooling capacity of the refrigerator is rapidly changed. This is because the solenoid valve is opened and the liquefied refrigerant is bypassed to the compressor suction side, and at the same time, the amount of the liquefied refrigerant to the evaporator is reduced by that amount, so that the cooling capacity in the evaporator is rapidly reduced. Because. Conversely, when the solenoid valve is closed with a decrease in the temperature of the refrigerant gas discharged from the compressor, the cooling capacity of the evaporator is rapidly increased.
Such a rapid change in the cooling capacity also has a great effect on the temperature and humidity control for the test room.
A sudden change in the cooling capacity causes disturbance in the temperature and humidity control, which makes it impossible to stably maintain a constant temperature and constant humidity state.

[0004] The first object of the present invention, even when the compressor discharge refrigerant gas temperature as raised, constant temperature and humidity, which is possible to maintain a constant temperature and humidity conditions to high From <br/> constant The present invention provides a method for controlling a refrigeration cycle of a device. A second object of the present invention is to provide a <br/> constant temperature ShimeSo location such refrigeration cycle control method is applied.

[0005]

SUMMARY OF THE INVENTION The above first object, the condenser outlet is provided in the middle bypass circuit connecting the compressor suction side, the valve of the electronic proportional control valve Waso as a pressure reducing mechanism opens The degree is initially set at the start of operation, and the valve
After the initial setting of the opening, the refrigerant gas on the compressor discharge side
Compressor so that the temperature always matches the set refrigerant gas temperature
The refrigerant gas temperature on the discharge side is always detected, and
Predetermined based on the deviation from the temperature and the polarity of the deviation
The pulse motor is generated by the drive pulse generated in the cycle.
This is achieved by variably controlling the valve opening by being rotationally driven . The second purpose is to provide a compressor discharge side
A discharge gas temperature sensor that constantly detects the refrigerant gas temperature of the
The refrigerant gas temperature from the discharge gas temperature sensor and a preset
Deviation between the refrigerant gas temperature and the comparison deviation
A refrigerant gas temperature difference calculating means for determining the polarity of the refrigerant gas;
The comparison deviation from the temperature difference calculation means and the polarity of the comparison deviation
A drive pulse is generated at a predetermined cycle based on the
The pulse motor drives the pulse motor to rotate.
The refrigerant gas temperature on the compressor discharge side to the set refrigerant gas temperature.
Initially set the valve opening of the electronic proportional control valve to match
Valve opening control means for variably controlling the set valve opening as a center;
This is achieved by providing a refrigeration cycle control device comprising:

[0006]

The opening degree of an electronic proportional control valve as a pressure reducing mechanism, which is provided in the middle of a bypass circuit connecting a condenser outlet and a compressor suction side, is determined by setting a refrigerant gas temperature on a compressor discharge side. the convex-ku pulse motor drive to the difference between the temperature is that attempts to control the <br/> variable. That is, when the compressor discharge-side refrigerant gas temperature is higher than the set refrigerant gas temperature, the valve opening is set to be larger than the initially set valve opening in accordance with the magnitude of the difference, while, conversely, When the compressor discharge-side refrigerant gas temperature is lower than the set refrigerant gas temperature, the valve opening is set to be smaller than the initially set valve opening according to the magnitude of the difference. As described above, when the valve opening degree of the electronic proportional control valve is variably and continuously controlled based on the difference between the compressor discharge side refrigerant gas temperature and the set refrigerant gas temperature, the compressor discharge side refrigerant gas temperature The amount of the liquefied refrigerant bypass and the amount of the liquefied refrigerant to the evaporator are also gradually and continuously changed so that the refrigerant gas temperature always matches the set refrigerant gas temperature, so that a rapid change in the refrigerating capacity is suppressed. is there. Thereby, the constant temperature and constant humidity state can be stably maintained.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to FIGS. First, the thermo-hygrostat according to the present invention will be described. FIG. 2 shows the configuration of an example of the thermo-hygrostat according to the present invention. In this case, various test objects (not shown) are accommodated in the test chamber 2 as a main part of the thermo-hygrostat, and the electric and thermo-hygro condition is updated to a predetermined value. Characteristics and the like are measured. Therefore, the test chamber 2 is configured as a closed space closed by the heat insulating layer 1 so as not to be affected by the external atmosphere temperature and humidity, while the internal constant temperature and humidity state is updated and controlled so that the heater 6 and the humidifier are controlled. A heater 7, an evaporator (a part of a refrigerator) 12, a dry-bulb temperature sensor (for temperature control) 3, and a wet-bulb temperature sensor (for humidity control) 4, which are provided in a predetermined manner in the test chamber 2 . Has become. Also in the test chamber 2, the circulation blower 5 is provided, which, by performing the air blowing direction of the arrow 15, is intended to equalize the constant temperature and humidity conditions in the test chamber 2, The dry-bulb temperature sensor 3 and the wet-bulb temperature sensor 4 are provided near the outlet of the circulating blower 5.

In the constant temperature and humidity apparatus according to the present invention, the control of the temperature of the discharged gas in the refrigerating cycle is a feature of the constant temperature and humidity control aside. As shown,
The structure of the refrigerator except for the evaporator 12 is shown in the lower part of the test chamber 2 , and the general operation of the refrigerator is as follows. That is, the refrigerant gas from the evaporator 12 is compressed by the compressor 8 and then condensed by the condenser 9 provided with the blower 10 to be liquefied. The liquefied refrigerant from the condenser 9 is then decompressed by the decompression device 11 and then vaporized by the heat from the test chamber 2 by the evaporator 12, so that the test chamber 2 is cooled. The refrigerant gas from the evaporator 12 is compressed again by the compressor 8, so that the refrigerant is circulated.

The general operation of a refrigerator is as described above. The characteristic features of the refrigerator according to the present invention are as follows.
In the middle of the bypass circuit connecting the outlet and the compressor 8 suction side,
An electronic proportional control valve 13 as a pressure reducing mechanism is provided, while a discharge gas temperature sensor 14 is provided on the discharge side of the compressor 8 to detect the temperature of the refrigerant gas. After the refrigerant gas temperature detected by the discharge gas temperature sensor 14 is compared with the set refrigerant gas temperature, the valve opening of the electronic proportional control valve 13 is variably and continuously controlled based on the temperature difference. Things.

FIG. 3 shows an outline of temperature and humidity control and discharge gas temperature control in the constant temperature and humidity apparatus shown in FIG. As shown in the figure, the detected temperature from each of the dry bulb temperature sensor 3 and the wet bulb temperature sensor 4 is compared with a set temperature / humidity from a microcomputer for controlling a constant temperature and humidity apparatus by a temperature controller, and is calculated.
The temperature and humidity are controlled with high accuracy by controlling the heater 6 and the humidifying heater 7 (for example, proportional / integral / differential control) based on the comparison calculation result. On the other hand, in the discharge gas temperature control related to the dehumidification cooling, the refrigerant gas temperature detected from the discharge gas temperature sensor 14 is compared with the set refrigerant gas temperature from the microcomputer for controlling the constant temperature and humidity device by the pulse motor controller. A drive pulse to the pulse motor is generated in a predetermined manner based on the result of the comparison operation. The pulse motor provided in the electronic proportional control valve 13 is rotationally driven by this drive pulse, and in conjunction with this, the electronic proportional control valve 1
The degree of opening at 3 is also changed. Therefore, when the rotation direction and the rotation amount of the pulse motor are controlled as desired by the drive pulse, the opening of the electronic proportional control valve 13 can also be controlled as desired.

FIG. 1 shows in detail the control flow of the opening of the electronic proportional control valve at that time. In this case, when the refrigerator is started to operate, first, an initial opening degree (normally fully closed) of the electronic proportional control valve 13 is set. Thereafter, the detected refrigerant gas temperature from the discharge gas temperature sensor 14 is constantly compared with the set refrigerant gas temperature, and based on the comparison operation result, for example, driving the pulse motor at a predetermined cycle under proportional / integral / differential control A pulse is generated in a predetermined manner. More specifically, the rotational driving direction of the pulse motor, that is, the opening direction of the electronic proportional control valve 13 is determined based on the polarity of the comparison operation result, and the number of driving pulses is controlled under proportional, integral, and differential control. Is to be determined. Thus, when the detected refrigerant gas temperature is higher than the set refrigerant gas temperature, the opening of the electronic proportional control valve 13 should be larger than the initial opening. The opening of the control valve 13 is controlled with high precision so as to be smaller than the initial opening, and as a result, the compressor discharge-side refrigerant gas temperature is controlled to always match the set refrigerant gas temperature.

In the above description, the compressor discharge side refrigerant gas temperature is positively detected and the refrigerant gas temperature is controlled to match the set refrigerant gas temperature. Even if the compressor suction-side refrigerant gas temperature is used instead of the gas temperature, it is inevitable that the control will be somewhat complicated, but the solenoid valves provided in each of the plurality of liquid bypass circuits connected in parallel are inevitable. It is also conceivable to perform switching opening / closing control in a predetermined manner.

Finally, considering the degree of effect of the present invention, FIG. 4 shows the change in the discharge refrigerant gas temperature and the cooling capacity with the change in the ambient temperature of the constant temperature and humidity apparatus. (Characteristic A), when the discharged refrigerant gas temperature was controlled by an electronic proportional control valve (Characteristic B), and when the discharged refrigerant gas temperature was controlled by a capillary tube and a solenoid valve (Characteristic C). Things. As shown in the figure, the discharge refrigerant gas temperature also increases with an increase in the ambient temperature. However, in the case of the electronic proportional control valve, when the discharge refrigerant gas temperature reaches the set discharge refrigerant gas temperature, the drive pulse is sent to the pulse motor. Is output and the opening degree of the electronic proportional control valve is controlled to increase. As a result, the discharge refrigerant gas temperature is controlled so as to match the set discharge refrigerant gas temperature after that point. On the other hand, when the capillary tube and the electromagnetic valve are used together, the electromagnetic valve is fully opened when the discharge refrigerant gas temperature reaches the set discharge refrigerant gas temperature, so that the cooling capacity is rapidly reduced. It has become something. However, in the case of the electronic proportional control valve, since the change in the cooling capacity is suppressed to a small value, disturbance in the temperature and humidity control does not occur in the test room, and the heating operation of the compressor can be prevented. ing.

[0014]

Effect of the Invention] As described above, when due to claim 1, even if the compressor discharge refrigerant gas temperature as raised, is it possible to maintain a constant temperature and humidity conditions high stability According to the refrigeration cycle control method of the constant temperature and humidity apparatus, and in the case of the second aspect, a constant temperature and humidity apparatus to which such a refrigeration cycle control method is applied can be obtained.

[Brief description of the drawings]

FIG. 1 is a diagram showing an opening control flow of an electronic proportional control valve according to the present invention.

FIG. 2 is a diagram showing a configuration of an example of a thermo-hygrostat according to the present invention.

FIG. 3 is a diagram showing an outline of temperature and humidity control and discharge gas temperature control in the constant temperature and humidity apparatus.

FIG. 4 is a diagram for considering the degree of the effect of the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Heat insulation layer, 2 ... Test room, 6 ... Heater, 7 ... Humidifier heater, 8 ... Compressor, 9 ... Condenser, 11 ... Decompression device, 12
... Evaporator, 13 ... Electronic proportional control valve, 14 ... Discharge gas temperature sensor

──────────────────────────────────────────────────の Continued on the front page (72) Inventor Hiroshi Watanabe 390 Muramatsu, Shimizu-shi, Shizuoka Prefecture Inside the Shimizu Plant, Hitachi, Ltd. (72) Inventor Yuji Kawaguchi 390 Muramatsu, Shimizu-shi, Shizuoka Prefecture Hitachi Shimizu Engineering Co., Ltd. (72) Inventor Akinori Sakurai 390 Muramatsu, Shimizu-shi, Shizuoka Prefecture Within Hitachi Shimizu Engineering Co., Ltd. (56) References JP-A-3-225161 (JP, A) (58) Fields investigated (Int. Cl. ⁶⁾ , DB name) F25B 1/00

Claims (2)

(57) [Claims] 1. A constant-temperature and constant-humidity device in which a space region as a test room, which is closed by a heat insulating layer, can be cooled by a refrigerator and the temperature and humidity in the space region can be controlled as desired. a refrigeration cycle control method, a condenser outlet is provided in the middle bypass circuit connecting the compressor suction side, the valve opening degree of the electronic proportional control valve Waso as a pressure reducing mechanism once the initial time of starting the operation Set on the valve
In the initial setting after the opening, to the compressor outlet refrigerant gas temperature is consistent at all times to set the refrigerant gas temperature, the compressor
The refrigerant gas temperature on the discharge side is always detected, and
Predetermined based on the deviation from the temperature and the polarity of the deviation
The pulse motor is generated by the drive pulse generated in the cycle.
A method of controlling a refrigeration cycle of a thermo-hygrostat , wherein a valve opening is variably controlled by being driven to rotate . 2. A space between the condenser outlet and the compressor suction side, wherein a space area as a test chamber, which is closed by a heat insulating layer, is provided.
In the middle of the bypass circuit, an electronic proportional control valve as a pressure reducing mechanism
Together are a cooling allowed by the refrigerator which is provided, temperature and humidity in the space region is a constant temperature ShimeSo location made is desired to controllable, the refrigerant gas temperature at the compressor discharge side
Discharge gas temperature sensor that constantly detects
The refrigerant gas temperature from the sensor and the preset refrigerant gas
And the polarity of the comparison deviation with respect to the temperature
Refrigerant gas temperature difference calculating means, and a refrigerant gas temperature difference calculating means
Drive based on the comparison deviation from the stage and the polarity of the comparison deviation
A pulse is generated at a predetermined period, and the drive pulse
The rotary motor drives the compressor to discharge the compressor.
The side refrigerant gas temperature should always match the set refrigerant gas temperature.
Initially, the valve opening of the electronic proportional control valve is set to medium.
Refrigeration system comprising valve opening control means variably controlled as a heart
A constant-temperature and constant-humidity device provided with a cycle control device .