JPH0539404Y2 - - Google Patents

Description

[Detailed description of the invention] Industrial application field The present invention is a refrigeration system installed in an environmental test equipment for conducting environmental tests, etc., in which the capacity of the refrigerant of the refrigeration equipment is adjusted according to the wet bulb temperature in the environmental test chamber. The present invention relates to a refrigeration system that is controlled.

Prior Art As shown in FIG. 3, a conventional refrigeration system installed in an environmental test apparatus has an environmental test chamber 4 and a constant temperature air generation chamber 5 separated by a partition wall 3 into an environmental test apparatus 2 covered with a heat insulating material 1. There are some divided into Inside the constant temperature air generation chamber 5 are a humidifier 6, a compressor 7, a condenser 8, an expansion valve 9, an evaporator 10 of a refrigeration cycle connected in circulation to the evaporator 10, a heater 11, and an air circulation blower. 12 are arranged in series. Furthermore, the evaporator 10 and expansion valve 9 of the refrigeration cycle
The space between the evaporator 10 and the compressor 7 is short-circuited by a bypass pipe 14 via a solenoid valve 13. The electromagnetic valve 13 is connected to a control device 15 that controls opening and closing thereof, and the control device 15 is connected to a dry bulb temperature detector 16 arranged in the environmental test chamber 4. Then, the control device 15 controls, for example, the fourth
As shown in the figure, the electromagnetic valve 13 is configured to close when the temperature is below a set temperature (60° C.) based on the detection result of the dry bulb temperature detector 16, and to open when the temperature is above the set temperature. Note that 17 and 18 are ventilation holes provided in the partition wall 3.

Therefore, in the case of this device, when the set temperature in the environmental test chamber 4 is raised, the amount of refrigerant supplied to the evaporator 10 increases due to the action of the expansion valve 9 as the temperature rises, and heat exchange between the refrigerant and the circulating air increases. The amount increases, and the temperature difference between the temperature of the air passing through the evaporator 10 and the set temperature increases.

Since the capacity of the heater for maintaining the set temperature increases or the refrigerant is overheated in the evaporator 10, the enthalpy of the refrigerant increases and the compressor 7 tends to be overloaded.

Therefore, the electromagnetic valve 13 that constitutes the capacity control device is opened, the refrigerant flowing from the expansion valve 9 to the evaporator 10 is branched, the amount of refrigerant supplied from the expansion valve 9 to the evaporator 10 is reduced, and the capacity of the heater 11 is increased. and compressor 7
prevents overload.

Problems to be Solved by the Invention However, in the case of such conventional refrigeration equipment, the dry bulb temperature detector installed in the environmental test chamber is completely unrelated to the humidity in the environmental test chamber 4, so the solenoid valve is activated at the set temperature. Because the humidity in the environmental test chamber varies when the system is activated, it ends up being activated even though it does not need to be activated as a capacity control. Furthermore, when the humidity is low, more refrigerant bypasses the evaporator than evaporates in the evaporator, resulting in liquid return, which has an adverse effect on the compressor.

Therefore, in view of the drawbacks of the conventional technology, the present invention
It is an object of the present invention to provide a refrigeration system with a refrigerant capacity control device that places less load on a compressor.

Means for Solving the Problems That is, the present invention provides a refrigeration system for an environmental test device in which a refrigeration cycle evaporator, a heater, and a blower are arranged in a constant temperature air generation chamber of the environmental test device. It consists of a bypass pipe that is connected to the condenser, an expansion valve, and an evaporator in circulation and short-circuited between the compressor and the evaporator and between the evaporator and the expansion valve via a solenoid valve, and is installed in the environmental test chamber of the environmental test equipment. This purpose is achieved by a refrigeration system with a capacity control device, in which a wet bulb temperature detector is installed, and a control means for controlling the opening and closing of the solenoid valve by comparing the temperature signal detected by the wet bulb temperature detector with a set temperature. achieve.

Embodiments The present invention will be described in detail below with reference to embodiments shown in the drawings.

In FIG. 1, reference numerals 1 to 15 are the same as those described in the prior art, so their explanation will be omitted.

That is, in the refrigeration system of this embodiment according to the present invention, a wet bulb 19 containing moisture is attached to the tip of the wet bulb temperature sensor 20 instead of the dry bulb temperature sensor 16 of the conventional device shown in FIG. It was connected to the control device 15 using a

In the case of the refrigeration apparatus according to the present invention having the above-described configuration, the set wet bulb temperature is set to 39.9° C., for example, as shown in FIG.

The air whose humidity has been adjusted by the humidifier 6 is cooled and dehumidified by the evaporator 10, heated to a set temperature by the heater 11, and then discharged into the environmental test chamber 4 by the blower 12. The temperature of the wet bulb temperature detector 20 installed in the environmental test chamber 4 decreases depending on the amount of moisture in the air discharged from the blower 12 due to the latent heat of evaporation of the wick 19. When reaching parts B and C in the figure, the solenoid valve 13 is activated. When the solenoid valve 13 is activated, the refrigerant liquid is branched and returns directly to the compressor 7, so that the evaporator 1
The amount of refrigerant liquid supplied to the evaporator 10 decreases, and the amount of heat exchanged with the air in the evaporator 10 decreases. In the case of the device of this embodiment, since it is configured to be controlled by wet bulb temperature rather than dry bulb temperature, the temperature which conventionally did not operate in area B (60 degrees Celsius or less in dry bulb temperature conversion), Since the solenoid valve 13 is activated in the humidity range, the control area is changed.

Effects As described above, according to the refrigeration system according to the present invention, the capacity control region operates in a lower temperature range compared to conventional ones, so the load on the compressor is reduced and the heating It is economical because the capacity of the container is small.

[Brief explanation of the drawing]

Figures 1 and 2 show an embodiment of the apparatus according to the present invention. Figure 1 is a longitudinal cross-sectional view of the apparatus showing the state in which the refrigeration equipment is attached to the environmental test equipment, and Figure 2 is the control FIG. 3 is a vertical cross-sectional view showing a state in which a conventional refrigeration device is installed in an environmental test device; FIG. 4 is a graph showing an operating range of a conventional control device. 1...Environmental test device, 2...Insulating material, 3...Partition wall, 4...Environmental test chamber, 5...Constant temperature air generation chamber, 6...Humidifier, 7...Compressor, 8...Condensation device, 9... expansion valve, 10... evaporator, 11... heater, 12... blower, 13... solenoid valve, 14
... Bypass pipe, 15 ... Control device, 16 ... Dry bulb temperature detector, 17, 18 ... Ventilation hole, 19 ...
Uitsuku, 20...Wet bulb temperature detector.

Claims (1)

[Scope of utility model registration request] In a refrigeration system of an environmental test equipment in which a refrigeration cycle evaporator, a heater, and a blower are disposed in a constant temperature air generation chamber of an environmental test equipment, the refrigeration cycle is cyclically connected to a compressor, a condenser, an expansion valve, and an evaporator. It consists of a bypass pipe that short-circuits between the compressor and evaporator and between the evaporator and expansion valve via a solenoid valve, and a wet bulb temperature detector is installed in the environmental test chamber of the environmental test equipment. A refrigeration system with a capacity control device, comprising a control means for controlling opening and closing of the solenoid valve by comparing a temperature signal detected by a temperature detector with a set temperature.