JPH0432599Y2 - - Google Patents

Description

[Detailed explanation of the idea]

INDUSTRIAL APPLICATION FIELD The present invention relates to an environmental test device that can create a sealed space at any temperature and adjust the humidity of this space to any desired level. Prior Art As shown in FIG. 8, this type of conventional environmental test device is designed to connect an environment test device 2 covered with a casing 1 made of a heat insulating material to a test chamber 6 via a partition plate 4 with constant temperature and humidity air. A compressor 10 is installed in the constant temperature and humidity air supply chamber 8.
The evaporator 16 of the refrigeration cycle is cyclically connected to the condenser 12, expansion valve 14, evaporator 16, and accumulator 18, an electric heater 20, a blower 22 for air circulation, and a humidifier 24 for forced humidification. A humidity sensor is installed in which the electric heater 20 is connected to a temperature control device 28 that adjusts the amount of power supplied based on the detected temperature from a temperature sensor 26 installed in the test chamber 6, and a humidifier 24 is installed in the test chamber 6. A device configured to be connected to a humidity control device 32 that adjusts the amount of power supplied based on the detected humidity from the humidity control device 30 is known. In the conventional device with the above configuration, the humidifier 2
After the air humidified in step 4 is cooled by an evaporator 16, it is heated by an electric heater 20 to adjust the air to a predetermined temperature. The adjusted air is then blown into the test chamber 6 by an air circulation blower 22 to maintain the test chamber 6 at a set temperature. Humidity control was performed by controlling the electric power supplied to the humidifier 24 with a control device 32 based on the detected humidity from a humidity sensor 30 installed in the test chamber 6. Problems that the invention attempts to solve However, with such conventional environmental test equipment,
Since the humidifier is configured to perform forced humidification as a humidifying means, frost tends to form on the evaporator that cools the air in low humidity ranges, blocking the air passage of the evaporator and hindering the cooling of the refrigeration cycle. There is a disadvantage that efficiency decreases. Furthermore, in order to remove the frost attached to the evaporator,
It has the disadvantage that it must be defrosted frequently, making it unsuitable for continuous environmental testing. If you want to keep the temperature low and high humidity without using a humidifier, it is necessary to throttle down the evaporation pressure adjustment valve to bring the evaporation temperature close to the set temperature, but if the amount of refrigerant decreases and the superheat portion increases, this will cause problems. be. Therefore, in view of the drawbacks of the prior art, it is an object of the present invention to provide an apparatus that can set the inside of an environmental test apparatus to any temperature and humidity. Means to Solve the Problems In other words, the present invention consists of a refrigeration cycle that is cyclically connected to a compressor, a condenser, an expansion valve, an evaporator, and an evaporation pressure regulating valve within an environmental test device covered with a casing made of a heat insulating material. In a device arranged with an evaporator, an electric heater, and an air blower, a solenoid valve and an expansion valve connected in series are connected in parallel with the expansion valve between the refrigerant outlet of the condenser and the refrigerant inlet of the evaporator. , the refrigerant outlet of the expansion valve and the refrigerant inlet of the accumulator are connected via a capillary reach tube, and the control device determines the set humidity based on the detection signal from the humidity sensor installed in the environmental test device. The humidity control mechanism is configured such that the opening of the evaporation pressure regulating valve is adjusted so that the expansion valve is switched on and off by the solenoid valve, and the electric heater is heated based on the temperature detected by the temperature sensor. This objective is achieved by an environmental test device equipped with an instructive temperature control device. Function: In the apparatus according to the present invention, the refrigeration cycle and electric heater are operated to first bring the inside of the test chamber to a predetermined temperature. The solenoid valve connected in series with the expansion valve closes when low humidity is to be controlled, and opens when low temperature and high humidity is to be controlled. With the solenoid valve set according to the conditions as described above, the temperature and humidity are controlled as follows. The humidity in the test chamber is detected via a humidity sensor, and a control device adjusts the opening degree of the evaporation pressure regulating valve based on the humidity detected by the humidity sensor. When the humidity in the test room is higher than the specified humidity, instructions are given to widen the opening of the evaporation pressure regulating valve to lower the evaporation temperature of the evaporator, and when the humidity in the test room is lower than the set temperature, the evaporator is opened. Instructs to narrow the opening of the evaporation pressure regulating valve in order to raise the evaporation temperature. The temperature control device instructs to increase the amount of power supplied to the electric heater when the temperature in the test room is lower than the set temperature, and conversely increases the amount of power supplied to the electric heater when the temperature in the test room is higher than the set temperature. Instruct to reduce the amount. When the temperature is low and high humidity, the solenoid valve is opened, but
This increases the amount of refrigerant flowing into the evaporator, making it possible to compensate for a refrigerant shortage in the evaporator. As a result, the evaporation temperature of the evaporator can be set very close to the set temperature. As described above, the inside of the environmental test apparatus is set to a predetermined temperature and humidity under the control of the temperature control device and the humidity control device. Embodiment The present invention will be explained in detail below according to an embodiment shown in the drawings. 40 is an environmental test device covered with a casing 42 made of a heat insulating material, and the inside of the environmental test device 40 is divided by a partition plate 44 into a test chamber 46 and a constant temperature and constant humidity air supply chamber 48. A compressor 50, a condenser 52, a receiver 53, and an expansion valve 5 are installed in the divided constant temperature and constant humidity air supply chamber 48.
4. The evaporator 56 of the refrigeration cycle, which is connected in circulation to the evaporator 56, the evaporation pressure adjustment valve 58, the suction pressure adjustment valve 59, and the accumulator 60, an electric heater 62, and a circulation blower 64 are arranged. Between the refrigerant outlet of the receiver 53 and the refrigerant inlet of the evaporator 56, there are a solenoid valve 76 connected in parallel with the expansion valve 54, an expansion valve 77 for low temperature and high humidity connected in series, a solenoid valve 78, and a constant pressure for general humidification. The regulator valve 79 and those connected in series are connected, and the valves 54, 77,
The refrigerant inlet 79 is connected between the electronic evaporation pressure regulating valve 58 and the suction pressure regulating valve 59 via a capillary reach tube 57 which is a pressure reducing mechanism. The low temperature and high humidity expansion valve 77 is set at a higher pressure than a normal expansion valve. The evaporation pressure regulating valve 58 is configured so that the opening degree of the valve can be continuously changed by a drive circuit 70. A humidity sensor 66 and a temperature sensor are installed in the test chamber 46.

[Table] As shown in the graphs in Figures 2 and 3, the general humidification range is when the temperature is 10℃ or higher and the relative humidity is
When the humidity is above 50%, the low temperature and high humidity range is when the temperature is below 10℃ and the relative humidity is above 50%, and the low humidity range is when the humidity is generally below 40%. As a result, the refrigerant circulation circuit of the refrigeration cycle circulates as shown in Figure 4 when the humidity is low, as shown in Figure 5 when the temperature is low and high humidity, and as shown in Figure 6 during general humidification. It cycles like this. In the general humidification region, the evaporation pressure regulating valve 58 is controlled by the switch 84 according to instructions from the control device 68.
Since the switch is switched to the power supply circuit 82 side, it remains fully open. However, if the evaporation temperature falls below 0° C., frost will occur, so a valve 79 is used to increase the evaporation pressure. In this embodiment, the electronic evaporation pressure regulating valve 58 is configured not to operate at the beginning of changing the humidity setting value, but to remain open, and to operate once the temperature has been adjusted to the set temperature. The temperature sensor 67 is connected to a temperature control device 72, and the temperature control device 72 instructs to reduce the amount of power supplied to the electric heater 62 when the temperature in the test chamber 46 is high based on the set temperature.
When the temperature inside the test chamber 46 is low, the electric heater 6
Instruct to increase the amount of power supplied to 2. A power supply circuit 74 supplies predetermined power to the electric heater 62 according to instructions from the temperature control device 72 . Note that 80 is a humidifier that receives power from the power supply circuit 82 and evaporates water in the water tank. The humidifier 80 is used only when the absolute humidity in the environmental test chamber is extremely low and it is not possible to increase the absolute humidity in the test chamber 46 using only the moisture in the room (during general humidification). This is done by switching the switch 84. In this case, the humidity control device 68 issues an instruction to energize the power supply circuit 82, and the humidifier 80 is activated. In the environmental testing apparatus according to the present invention having the above-described configuration, each component is controlled to maintain a predetermined temperature and humidity as shown in the time chart shown in FIG. From state A (temperature 20℃, humidity 60%RH) to D
When setting for general humidification under conditions (temperature 10°C, humidity 90% RH), the evaporation pressure regulating valve 58 continues to cool the test chamber with the valve kept fully open. Then, the inside of the test chamber 46 is gradually cooled down to the set temperature of 10° C. against the heating of the electric heater 62 (state B). Next, after the temperature has dropped to the set temperature, the control device 6
Since the regulating valve 58 remains fully open due to no control by the humidifier 80, the evaporator continues dehumidifying, but since the amount of humidification from the humidifier 80 is large, the indoor humidity gradually increases (state C). Since the electromagnetic valve 78 is open at this time, the evaporation temperature is maintained at 0° C. or higher. As a result, the humidity increases while condensing on the evaporator and its surroundings, reaching the set 90% RH. From state D (temperature 10℃, humidity 90%RH) to F
When setting the humidity range to the low humidity range (temperature 10°C, humidity 10%RH), the switch 84 of the humidifier 80 is turned off.
The evaporation pressure regulating valve 58 is now controlled by the control device 68. Both solenoid valves 76 and 78 are in a closed state. Since the set temperature is the same as 10° C., the opening degree of the evaporation pressure regulating valve 58 is kept fully open, and dehumidification is performed. (E state). That is, dew condenses on the fins of the evaporator 56 and becomes frost, thereby dehumidifying the moisture in the air. After the humidity has been reduced to 10% of the set value, the control device instructs the drive circuit 70 to reduce the opening of the evaporation pressure regulating valve 58, increasing the evaporation pressure and maintaining the humidity. From F condition (temperature 10℃, humidity 10%RH) to I
When setting the temperature to the low temperature and high humidity range (temperature 0°C, humidity 90% RH), the solenoid valve 78 is closed and the solenoid valve 76 is open. Electronic evaporation pressure adjustment valve 58 valve opening 100%
Leave the test chamber to cool. Then, the inside of the test chamber 46 is gradually cooled down to the set temperature of 0° C. against the heating of the electric heater 62 (G state). Next, the opening degree of the electronic evaporation pressure regulating valve 58 is narrowed by an instruction from the control device 68, the evaporation pressure increases, and the evaporation temperature becomes 0° C. or higher. Therefore, the frost that had adhered to the fins of the evaporator 56 begins to melt and gradually evaporates, resulting in an increase in humidity (H state). At this time, the indoor temperature also rises somewhat. When the humidity becomes higher than the set humidity, the control device 68 instructs the electronic evaporation pressure regulating valve 58 to widen the valve opening, thereby reducing the evaporation pressure. At this time, since the solenoid valve 76 is open, the refrigerant is sufficiently supplied to the evaporator, and the evaporation temperature may be close to the set temperature. Therefore, relative humidity can be maintained high. As described above, the electronic evaporation pressure regulating valve 5
By adjusting the opening degree of 8 and switching the expansion valve, the inside of the environmental test apparatus can be maintained at a predetermined temperature and humidity. Effects As described above, in the environmental test device according to the present invention, the expansion valve is switched as appropriate according to the set temperature and humidity via the solenoid valve, and the evaporation pressure is adjusted using the temperature sensor and humidity sensor installed in the test chamber. Since the opening degree of the valve is configured to be changed, an environment suitable for all temperature and humidity ranges can be set. Furthermore, since the structure is configured so that humidity can be controlled without using a forced humidifier in the low temperature range where the evaporation temperature is 0° C. or lower and the low temperature and high humidity range, the evaporator of the refrigeration cycle is less likely to be frosted and has high energy efficiency. Furthermore, a humidity sensor is placed in the test chamber, and the evaporation temperature of the evaporator is controlled by a control device based on the humidity detected by the humidity sensor, making it possible to set the environment more accurately than with conventional equipment. .

[Brief explanation of the drawing]

Figures 1 and 7 show examples of the device according to the present invention, Figure 1 is a schematic diagram of the device, Figure 2 is a graph showing the relationship between absolute humidity and temperature, and Figure 3 is relative humidity. Figure 4 is a schematic diagram showing the flow of refrigerant in the refrigeration cycle in the low humidity range, Figure 5 is a schematic diagram showing the flow of refrigerant in the low temperature and high humidity range, and Figure 6 is the general diagram. FIG. 7 is a schematic diagram showing the flow of refrigerant in the humidification range, FIG. 7 is a time chart showing the operating state, and FIG. 8 is a schematic diagram of the device showing the prior art. 1,42...Casing, 2,40...Environmental test device, 4,44...Partition plate, 6,46...Test chamber, 8,48...Constant temperature and humidity air supply chamber, 10,5
0...Compressor, 12,52...Condenser, 14,5
4...Expansion valve, 16,56...Evaporator, 18,6
0...Accumulator, 20,62...Electric heater, 22,64...Blower, 24,80...Humidifier, 26,67...Temperature sensor, 28,72
... Temperature control device, 30, 66 ... Temperature sensor, 32, 68 ... Humidity control device, 58 ... Evaporation pressure regulating valve, 70 ... Drive circuit, 74 ... Power supply circuit, 76, 78 ... Electromagnetic Valve, 77... expansion valve, 80... humidifier, 79... constant pressure pressure adjustment valve.

Claims (1)

[Scope of utility model registration request] The compressor, condenser, expansion valve, evaporator, evaporation pressure adjustment valve, refrigeration cycle evaporator, electric heater, and air blower were placed in an environmental test device covered with a casing made of heat insulating material. In the apparatus, a solenoid valve and an expansion valve connected in series are connected in parallel with an expansion valve between a refrigerant outlet of the condenser and a refrigerant inlet of the evaporator, and a solenoid valve and an expansion valve connected in series are connected between the refrigerant outlet of the expansion valve and the refrigerant inlet of the accumulator. The control device adjusts the opening degree of the evaporation pressure regulating valve to achieve the set humidity based on the detection signal from the humidity sensor installed in the environmental test device. . An environmental test device, characterized in that the expansion valve is configured to be switched by turning on and off a solenoid valve.