JP2007178247A - Thermostatic type weatherability testing method and weatherability testing machine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a thermostatic type weatherability testing method for controlling the temperature in a testing container using the optimum energy without mounting a freezer having an excessive capacity, in order to remove a large quantity of the heat discharged from a light source and a heater in a weatherability testing machine, wherein a large quantity of heat is discharged from the light source, with enhanced temperature control capacity, preventing freezing of the cooler and with reduced operation power; and to provide a weatherability testing machine. <P>SOLUTION: The weatherability testing machine is constituted to control the temperature in a test tank by the freezer driven by an electromotor with an inverter and equipped with a technique for controlling the number of rotations of the electromotor so as to output the freezing capacity, corresponding to the quantity of the heat discharged from the light source and together using an electronic expansion valve, as necessary to not only hold the inside of the test tank to a set temperature, but also to raise the temperature in the test tank by the heater, when the temperature in the test tank goes into a supercooling state below the set temperature. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

The present invention relates to a constant-temperature weatherproof light testing machine that efficiently controls the temperature in a test tank by a refrigerator equipped with an inverter.

In the weathering light test for examining accelerated deterioration of a sample by irradiating light, a light source suitable for the sample to be tested is selected from various light sources in order to correspond to the deterioration behavior of the sample in the actual environment. A method is used in which the wavelength is adjusted between a sample and a light source through a filter, and the test is performed under conditions that approximate the behavior of deterioration in an actual environment.

As a light source, a xenon arc lamp, a sunshine carbon arc, an ultraviolet carbon arc, a metal halide arc lamp, and various fluorescent lamps are used. In order to maintain the temperature in the test chamber at the test setting conditions, the weatherproof light tester equipped with these light sources is equipped with an air conditioner, and the value obtained by the temperature sensor is attached to the air conditioner. The air conditioner is operated so as to be transmitted to the operation control device and satisfy the set conditions. (For example, Patent Document 1)
Japanese Patent No. 3705497

When the irradiance is low in a weathering light tester using a xenon arc lamp, the temperature in the test chamber is controlled by an air conditioner equipped with a normal heater and an outside air introduction mechanism.

However, when the irradiance is high, heat radiation from the lamp is increased, and the temperature in the test chamber is excessively increased only by introduction of outside air, and cannot be controlled. For this reason, in this tester, a cooler connected to the refrigerator is mounted on the air conditioner and controlled to the test set temperature so that low illuminance can be dealt with.

There is also a weathering light tester of a system in which an electronic expansion valve is attached between a refrigerator and a cooling pipe, and the refrigerant capacity is controlled by changing the refrigerant discharge amount.

In addition, there is an air conditioner for environmental test machines that does not include a light source composed of a heater, a humidifier, a plurality of refrigerators, and a system equipped with an electronic expansion valve or an inverter. There is a technology related to so-called unit control that continuously controls a large output from a small output by combining a large number of machines, and is intended for energy saving. (For example, Patent Document 2)
Japanese Patent Application No. 11-67330

In a weatherproof light testing machine equipped with a refrigerator that operates at a rated output, when testing is performed at low irradiance, the temperature in the test tank may be below the set temperature. In order to offset this supercooling state, the heater is operated. The energy of this supercooling and the energy of the heater necessary to offset this are essentially unnecessary, and therefore the conventional air conditioner to which this method is applied is inferior in energy efficiency.

Further, in a weatherproof light testing machine equipped with the electronic expansion valve together with a refrigerator operated at a rated value, when the temperature in the test tank is close to a set temperature, the opening degree of the electronic expansion valve is reduced, Operate with reduced cooling capacity. However, in this case, since the refrigerator is overloaded when the return amount of the refrigerant is reduced, the electronic expansion valve is not actually completely closed and the electronic device is operated so that the rated minimum load operation of the refrigerator is achieved. Since the operation of the expansion valve is adjusted, the function of the electronic expansion valve cannot be fully utilized.

Moreover, since the rotation speed of the electric motor of the refrigerator is controlled to be constant, the suction capacity of the refrigerator is always constant. If the opening of the electronic expansion valve is reduced in this state, the discharge amount of the refrigerant decreases, and the evaporation rate of the refrigerant in the cooler connected to the refrigerator increases, so the cooling pipe surface temperature of the cooler becomes remarkably high. And condensation occurs on the outer surface of the cooling pipe.

When the evaporation rate is extremely high, the condensed water freezes, and when the frozen layer becomes thick, the heat exchange efficiency on the surface of the cooler deteriorates, so the temperature in the test chamber rises. When the temperature exceeds the set temperature, a test control system mounted on the test apparatus for trying to follow the set condition outputs a signal for increasing the opening of the electronic expansion valve.

As a result, moisture condensed on the outer surface of the cooler freezes, and the refrigerant is discharged into the cooler in a state where the heat exchange efficiency is poor because it is covered with a frozen layer. The temperature of the test tank will deviate from the set value. In addition, if the refrigerant returns to the compressor without being completely vaporized, the performance of the compressor is reduced and a failure is caused.

As described above, various techniques are applied to the temperature control of the weathering light tester. However, in the weathering light tester that emits a large amount of heat from the light source, a temperature range of about −20 ° C. to about 80 ° C. A weather resistance test system that realizes air conditioning in the relative humidity range of 100% to 100% within a short period of time, and also considers the prevention of freezing of condensed water on the surface of the cooler, and also controls the temperature with a single refrigerator. Is not found.

The present invention is intended to solve such a problem that could not be achieved in the past, and an energy-saving type having an optimum capacity without mounting an economically expensive refrigerator and heater having an excessive capacity. An object of the present invention is to provide a weathering light test system that is equipped with a refrigerator and a heater, controls the temperature in the test tank with good energy efficiency, and does not freeze on the cooler surface. .

In order to achieve the above-mentioned purpose, for example, when the irradiance is set high in a weatherproof light tester using a xenon arc lamp, a metal halide arc lamp, a sunshine carbon arc lamp, and an ultraviolet carbon arc lamp as a light source, the temperature of the sample increases. Therefore, it is necessary to control the temperature, humidity, and, in some cases, the wind speed in the vicinity of the sample, and for this purpose, an inverter for controlling the number of revolutions of the humidifier, heater, and motor is installed in the air-conditioning section of the test machine. The purpose is to provide an energy-saving weathering test method with good reproducibility and temperature control by changing the output frequency from the inverter stepwise by providing a cooler connected to the refrigerator It is.

There are inverters that can continuously change the frequency and inverters that select a plurality of predetermined frequencies. When the former refrigerator is operated, the refrigeration capacity can be continuously changed, and in the latter case, discontinuous refrigeration capacity is obtained.

In the case of the former continuously variable inverter, if the value of the temperature sensor installed in the test chamber is higher than the value of the test set temperature, the signal from the inverter is controlled by a signal from the operation control device of the weathering light tester. The output is changed according to the difference between the value of the temperature sensor installed in the test tank and the value of the test set temperature, and the refrigerator is operated until the value of the temperature sensor reaches the test set temperature. .

In the case of a condition in which the temperature change in the test tank frequently occurs, the frequency of the inverter changes with the temperature change, and for this reason, the rotation speed of the refrigerator also changes frequently. Since the refrigerator is a kind of compressor, it cannot follow a rapid transient response, and when the number of revolutions increases suddenly, the load on the movable part increases and the life of the machine is shortened. Therefore, frequent changes in frequency must be avoided as much as possible.

The present invention relates to a method of adjusting the temperature by selecting the frequency of an inverter stepwise and operating it without frequently changing the rotation of the refrigerator. That is, when operating the refrigerator with an inverter of the type that selects the frequency, the minimum output of the refrigerator that can bring the temperature in the test tank below the set temperature when the output of the light source is changed in advance, The frequency of the inverter is obtained, and the frequency is registered in the storage circuit of the operation control device.

When performing the weathering test, based on the relationship between the output of the light source registered in the operation controller and the frequency of the inverter, the refrigerator is operated at the frequency corresponding to the output of the light source, When the temperature falls below the set temperature, the heater is operated to adjust the temperature.

If the temperature in the test tank is equal to or higher than the set temperature even after cooling at the frequency, the control panel issues an instruction to change the frequency value to a value that increases the one-stage refrigeration capacity. Even when the output of the light source is changed, or when the irradiation intensity of the light source fluctuates due to deterioration or the like, the control panel selects a frequency corresponding to the output of the light source and gives an instruction to the inverter, and the one-stage refrigeration capacity In the case where the value that increases becomes different from the frequency connected to the output of the light source, priority is given to the value that increases the one-stage refrigeration capacity.

Since the temperature control becomes discontinuous only with the inverter, the electronic expansion valve is attached to the refrigerator and operated, and the opening degree of the electronic expansion valve is changed according to the degree of deviation from the set temperature. Less temperature control can be realized. Proportional control or PID control is applied to the control at this time.

Most of the samples to be tested with the above-mentioned weather light tester are used in a real life environment. In this case, in order to match the deterioration in the real environment with the result of the weather light test, it is as practical as possible. It must be tested under accelerated aging conditions that reproduce the environment. For this purpose, the temperature is controlled between 35 ° C. and 40 ° C., which is not affected by the heat from the light source installed in the test chamber, and when a lamp with a large heat dissipation from the light source is used. In order to keep the sample surface temperature constant, the conventional apparatus responds by changing the wind speed in the test chamber, but there is a defect that affects the deterioration of the sample. If the technique of the present invention is used, the test can be performed with the air volume and the wind speed kept constant.

According to the present invention, it is possible to perform temperature control with energy saving and excellent temperature control capability without mounting an excessive capacity refrigerator and heater, without freezing the cooler during cooling. Therefore, it is possible to provide a weatherproof test system with good repeatability of test results and low power consumption. In addition, it is possible to test with the same testing machine even in regions where the frequency of the commercial power source is different.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the invention will be described based on examples with reference to the drawings. FIG. 1 is a connection diagram of main components related to the present invention in a constant temperature type weatherproof light testing machine equipped with a xenon arc lamp.

There is a vertical water-cooled xenon arc lamp 2 in the center of the test chamber 1, and a rotary sample frame 3 is installed around the vertical water-cooled xenon arc lamp 2. A sample 4 and a black panel thermometer 5 are attached to the rotary sample frame 3. Has been.

A part of the upper part of the test tank 1 is opened, and a circulation blower 6 for circulating an air flow adjusted in temperature and humidity in the test tank is attached in the vicinity of the opening.

A dry bulb thermometer 7 and a hygrometer 8 are attached to the wall surface in the test tank near the opening of the test tank 1 while being shielded from the light source. A cooler 9 is attached to the lower part of the circulation fan 6, and the airflow is cooled when passing through the cooler 9. The cooler 9 is connected to the electronic expansion valve 10, the refrigerator 11, and the inverter 12.

A humidifier 13 and a heater 14 are installed below the cooler 9.

Although not shown in the figure, the cooler 9, the humidifier 13, and the heater 14 are controlled in accordance with the load power of the xenon arc lamp 2, the signals of the black panel thermometer 5, the dry bulb thermometer 7, and the humidity sensor 8. There is an operation control device.

Testing machine with xenon arc lamp lighting power of 7.5kW, 4.5kW refrigerator and 3kW heater, and when xenon arc lamp is lit, testing machine without conventional inverter However, the refrigerator was operated in the rated state regardless of the lighting power, and the temperature was adjusted by changing the capacity of the heater. In the present invention, an inverter is mounted on the refrigerator in the test machine. By selecting the frequency step by step, the temperature is adjusted without using unnecessary energy. When the lighting power is 5 kW or more, the output frequency of the inverter is 45 Hz, and between 3 kW and 5 kW is 40 Hz. In the case of 3 kW or less, it was set in three stages of 35 Hz.

In the dark (no lighting), the frequency was set to 35 Hz. The rated output of the refrigerator is a value at 50 Hz, and the output of the refrigerator changes in proportion to the output frequency of the inverter. The frequency was selected by two relays (tentative name relay 1 and relay 2) connected to the 4-bit control terminal of the inverter.

That is, 45 Hz when the relays 1 and 2 are OFF, 40 Hz when the relay 1 is ON and the relay 2 is OFF, and 35 Hz when the relay 1 is OFF and the relay 2 is ON.

The heat radiated by the xenon arc lamp corresponds to approximately 3 kW when the lighting power is 7.5 kW, and this value varies substantially in proportion to the lighting power. Based on this value, the frequency of the refrigerator was selected. Therefore, the power consumption of the refrigerator can be reduced as the lighting power is lower, and the power value of the heater that has been operated to prevent overcooling can be lowered accordingly.

In the test machine of the example, since the electronic expansion valve is operated, it is difficult to detect the power consumption in each part, but when compared with the case where the inverter was not used when the lighting power was 3 kW (inverter (When the frequency is 35 Hz) is described below.

When using an inverter When not using an inverter 1: Lamp lighting power 3 kW 3 kW
2: Heat dissipation from the lamp 1.2 kW 1.2 kW
3: Refrigerator motor load power 1.05 kW 1.5 kW
4: Refrigeration output 3.15 kW 4.5 kW
5: Heater operating power 0 kW 1.35 kW
Total: 1 + 3 + 5 4.05 kW 5.85 kW

The above-mentioned value is a trial calculation result in a state where the difference is the most significant, and the energy saving operation is about 31%. In the case of an actual test, energy saving operation between approximately 0% and 30% is possible.

Although it is an effective method to control the temperature by changing the refrigerant discharge amount with an electronic expansion valve, if the discharge amount is reduced below the lower limit capacity of the refrigerator, the refrigerator will be overloaded and the refrigerant will evaporate. As the speed increases, the cooler temperature decreases and the surface of the cooler freezes, reducing the cooling capacity, and the test chamber temperature begins to rise. The operation control device gives an instruction to increase the refrigerant discharge amount, and the frozen layer on the surface of the cooler becomes thick, and in severe cases, the flow of air is blocked and the liquid refrigerant returns to the compressor. End up. Compressing this liquid causes failure of the compressor of the refrigerator and is not preferable.

When an inverter is used, such an excessive load does not act on the cooling system.

It is a connection related figure of the main components in the constant temperature type weatherproof light testing machine carrying a xenon arc lamp.

Explanation of symbols

1. Test tank 2, Xenon arc lamp 3, Sample frame 4, Sample 5, Black panel thermometer 6, Circulating fan 7, Dry bulb thermometer 8, Humidity sensor 9, Cooler 10, Electronic expansion valve 11, Refrigerator 12 , Inverter 13, humidifier 14, heater

Claims (7)

A weathering light test method that uses any one of xenon arc, metal halide arc, sunshine carbon arc, and ultraviolet carbon arc as a light source, and controls the temperature in the test chamber at different outputs of the light source. The machine is equipped with a cooler that controls the temperature by selecting the number of rotations of the refrigerator with an inverter that can select and set multiple frequencies in stages, and when cooling at a selectable frequency in advance The relationship between the output of the light source, the frequency of the inverter, and the temperature in the test chamber is obtained, and the data is stored in the operation control device, and the frequency is selected so that the conditions closest to the set temperature are selected. When the temperature in the test chamber is higher than the set temperature, the refrigerator is operated at a frequency one step higher than the frequency to cool it. When the temperature in the test tank is lower than the set temperature, the expansion valve and the heater connected to the refrigerator are operated according to the difference between the set temperature and the temperature in the test tank. A constant temperature type weatherproof light test method characterized by comprising: When the test is performed under the condition that the refrigerator operates at the lower limit of the rated operation range, the operation is maintained at the lower limit of the rated operation range of the refrigerator without stopping the refrigerator. The constant temperature type weather resistance test method according to claim 1, wherein a temperature of the test chamber is controlled by operating a heater. Control the temperature in the test chamber with a cooler and a heater composed of an expansion valve and a refrigerator that can control the flow rate and speed of the airflow flowing in the test chamber, and that can control the discharge amount of the inverter and refrigerant. The constant temperature type weatherproof light test method according to claim 1 or 2, characterized in that: 5. The constant temperature type weatherproof light test method according to claim 1, wherein a dry bulb thermometer installed in the test tank is controlled to indicate between 35 ° C. and 40 ° C. 6. The set temperature is controlled so that the indicated temperature of the black panel thermometer consisting of a metal plate and a heat-sensitive part, which are baked and finished by spraying the weather-resistant black enamel attached to the sample frame in the test chamber, is kept constant. The constant temperature type weatherproof light test method according to claim 1, wherein: The temperature of the black standard thermometer with the heat-sensitive part fixed to the center of the back side of a metal plate that has been baked and finished by spraying the weather-resistant black enamel attached to the sample frame in the test chamber twice, and the temperature indicated by the black standard thermometer is constant The constant temperature type weatherproof light test method according to claim 1, wherein the set temperature is controlled so as to be maintained at a constant temperature. A constant temperature type weather resistance tester for carrying out the constant temperature type weather resistance test method according to claim 1.