JP3945784B1 - Highly controlled weathering tester - Google Patents

Abstract

A weathering tester that irradiates a sample with a constant irradiance and has excellent temperature controllability is provided.
The present invention provides an inverter-controlled AC power source to supply power having a stable waveform to a light source after confirming that the components of the weathering tester operate normally prior to the start of the test. Thus, the test is performed with a constant irradiance, and the temperature in the test tank is prevented from deviating from the set condition by adding the thermal characteristics emitted from the light source to the temperature control arithmetic circuit.
[Selection] Figure 1

Description

The present invention uses a xenon arc lamp, a metal halide arc lamp or the like as a light source, and applies a preset discharge power from a power source controlled by an inverter at the start of lighting of the light source, and at the time of steady lighting maintaining a constant irradiance The amount of refrigerant to be supplied to the output of the heater and the cooling coil based on the change in irradiance after starting lighting, while lighting the light source at a constant light intensity with a rectangular wave AC power at a frequency higher than the commercial frequency By controlling the temperature, the temperature of the black panel thermometer (hereinafter abbreviated as BPT) does not overshoot the holding temperature when reaching a temperature at which the test is held constant from the temperature rise state. About.

In a conventional weather tester, in order to stably control the energy radiated from a xenon arc lamp used as a light source or a metal halide arc lamp, a sample frame rotating around the light source or a fixed sample stage, Measure the irradiance with an irradiance meter placed in the same plane as the sample, and connect the irradiance value to the control unit of the weathering tester with a slip ring or radio connected to the irradiance meter. A control signal is transmitted to the lighting power source of the light source via an arithmetic circuit provided in the control unit so that the irradiance value of the test condition set in advance and the irradiance value measured by the irradiance meter coincide with each other. And the light intensity of the light source is adjusted by an automatic control method.

Apart from this, to prevent overloading of the light source,
(1) The lamp discharge power is monitored by the discharge power monitoring circuit connected to the lighting power source of the light source, and when it exceeds the specified value, the control signal is switched to the initial value held in the arithmetic circuit and is the same as the initial value. A method of lighting with discharge power,
(2) A method of turning on the light source based on an initial value preset in the arithmetic circuit and controlling the lighting power of the light source in response to a change with time of the radiant energy of the light source,
(3) In addition to the configuration of (1) above, when the discharge power based on the value of irradiance measured from the light receiver is lower than the preset discharge power value, the set irradiance is newly set. To reset the discharge power control value,
Etc. are done.
Patent No. 2774010

However, the lighting power supply part of these light sources is calculated by a circuit using a PID method or the like provided in the control unit of the weathering tester based on a signal from a light receiver or a lighting power signal, for example, a lighting discharge voltage and a lighting discharge current. The lighting discharge power is supplied to the light source by the signal.

The discharge power adjustment circuit of the lighting power supply unit is a phase control system, and generally uses the commercial AC power supply frequency as it is. In this phase control method, the power supplied to the light source is controlled by changing the voltage or current applied to the SCR gate. In the case of ideal control, a waveform obtained by cutting out a part of the sine waveform with the SCR is supplied as the output of the light source. However, due to the characteristics of the SCR, depending on the voltage applied to the gate, only one sine waveform is obtained. In some cases, a waveform having a plurality of peak voltages during a ½ cycle may be obtained, and the shape thereof is not stable, and the power supplied to the light source is the same as that described above during one cycle. Therefore, the irradiance in a short time fluctuates even if it is felt constant by the naked eye.

The intensity of light acting on paints, plastics, fibers, printed characters and images, photos, etc. in the real environment is not constant if observed for a long time, but the temporal change is morning, noon, It is a very gradual one that changes in the evening span. Since the light source of a conventional weathering tester discharges with electric power modulated with alternating current, if the irradiance is observed in a short range such as a millisecond, it becomes a fluctuating and unstable illuminance. For this reason, it is also possible that a reaction different from the mechanism of the photochemical reaction occurring in the actual environment occurs on the sample surface.

In addition, depending on the light source used, a long wavelength near the infrared is included. Since the long wavelength light acts as heat energy, the value of the BPT attached to the sample table or the sample frame is increased, and if the degree is large, the control capability of the air conditioner is exceeded, so that it deviates from the set temperature. There is a case.

The conventional weathering tester is equipped with a cooler that cools using a refrigerant and a heater that uses heat generated by electric resistance to control the temperature in the test tank to a specified value. During the test, the temperature in the tank is maintained at 38 ° C., and during the irradiation test, the test may be performed with a high irradiance such as 2500 W / m ^{2 with} a BPT value of 63 ° C. When the conventional tester control method is switched from the dark test to the irradiation test, the control circuit is set to a mode of increasing the temperature.

In this state, the heater is operated until the BPT value reaches 63 ° C., and at the same time, the thermal energy from the light source is superimposed, so when the BPT value reaches the vicinity of the set value. Even if the refrigerator is operated and the control for starting the cooling is executed, it may take a considerable time until the temperature exceeds the set temperature and recovers to 63 ° C. without being fully controlled.

This is because, as described above, the heat source for increasing the BPT value is composed of two places, that is, the heater and the light source. That is, although the temperature adjustment mechanism is connected to the heater, the light source must give priority to the control of the light intensity. Therefore, the power supplied to the light source cannot be changed in order to control the temperature. So far, the heater has been operated by PID control based on the difference between the set temperature and the value of BPT at the same time as lighting is started. For this reason, at the beginning of lighting when the temperature is low, the PID value becomes 100%, and the heater may operate at full power, so the BPT value rises rapidly. As the irradiance of the light source approaches the set value, the heat from the light source also affects the increase in the BPT value, and when the set temperature is reached, even if the amount of heat generated from the heater is reduced, the BPT temperature rise is rapidly stopped. It is because it is not possible.

When the test chamber is downsized and the amount of heat generated from the light source is reduced, the response speed to the temperature change is fast, so it is possible to control without deviating from the set temperature. In addition, when the amount of heat generated from the light source is large, it often deviates from the set value.

The present invention is intended to solve such a conventional problem, and confirms that the components of the weathering tester operate normally before the start of the test, and then uses an AC power source with a stable waveform. A weathering tester that performs a test at a constant irradiance and does not overshoot the holding temperature when the temperature reaches a temperature at which the test is held constant from a temperature rising state at the start of lighting. Is intended to provide.

When the weather tester of the present invention starts a test, it automatically air-conditions the temperature control arithmetic circuit of the weather tester to operate at a temperature set at the start of the test by operating a heater or a refrigerator in a temperature rising mode. To start. Similarly, when the dark test is switched to the irradiation test, the temperature raising mode is set. In this temperature increase mode, if the value of BPT is lower than the set temperature, the temperature is increased by the heater attached to the weathering tester in addition to the temperature increase by the energy from the light source. If many of the long wavelength components that become energy are contained, the temperature of the BPT may exceed the set value. In the present invention, a method is adopted in which the sign is grasped before the BPT value deviates from the set value, and control is performed by applying a load to the control object in advance based on the sign state. That is, the irradiance from the light source is low immediately after the start of lighting, and increases and stabilizes after a certain time. If the heater is operated in a high output state at the start of lighting and the temperature rise is started, the BPT value is set even if the output of the heater is decreased when the illuminance of the light source begins to increase or is increasing In the present invention, during the period from the start of lighting until the irradiance of the light source rapidly increases, the heater is not operated and heating is started when the irradiance of the light source starts to increase rapidly. And the BPT value is brought to a predetermined value. At this time, the refrigerator is operated from the start of lighting of the light source by PID control based on the value of BPT. Thus, it is possible to prevent the BPT value from deviating from the set value due to the influence of thermal energy from the light source.

In addition, when a test start signal is given to the weather tester, the state of each device constituting the weather tester, that is, the value of BPT, the temperature in the test chamber, the temperature of the conditioning room, the temperature of the lamp cooling water And whether or not the flow rate, humidity generator temperature and water level, internal pressure of the refrigerator, operating state of the safety circuit of the lighting power circuit, the state of the test chamber door lock confirmation switch, etc. are normal Judgment is automatically made by the provided device abnormality detection circuit. If an abnormality is detected, the abnormality is warned by light, sound, text, etc., and the transition to the next step is suspended until the abnormality is cleared. .

In addition, when it is detected that there is no abnormality and when the abnormality is canceled, the light source is turned on. At the time of lighting, a current value or a voltage value or a current value and a voltage value obtained in advance from an average value of a plurality of light sources of the same type are loaded on the light source from an irradiance control circuit provided in the control unit of the weather resistance tester. Therefore, a signal is transmitted to the lighting power source. The power supply for lighting is composed of an inverter type lighting power control circuit and a lighting power output circuit, and the brightness of the light source is increased by supplying alternating current power corresponding to the signal whose voltage is changed with a rectangular wave to the light source. Adjust.

Further, the irradiance is measured by a light receiver provided on a sample frame or a sample stage in the test tank, and the value is compared with the irradiance value of the test condition set at the start of the test by the irradiance control circuit. When there is a difference between these values, a discharge power control signal for eliminating the difference is calculated by the PID calculation circuit unit in the irradiance comparison circuit, and transmitted to the inverter type lighting power control circuit, The irradiance is adjusted by controlling the supply of the lighting power of the light source from the lighting power output circuit so as to obtain the set irradiance.

In addition, in order to use the light source stably for a long time, the values of the upper limit voltage and the upper limit current are set in advance, and these values are input to the discharge power comparison circuit, and the voltage and current supplied to the light source are When measured by a discharge power comparison circuit and the value exceeds the measured value, the power supplied to the light source is shut off by an operation switch provided in the weathering tester.

According to the present invention, after inspecting various safety circuits, the light source is turned on with an inverter-controlled lighting power source, thereby controlling the irradiance of light irradiating the sample to a constant level and changing the irradiance after starting lighting. On the basis, by controlling the output of the heater and the amount of refrigerant supplied to the cooling coil, the BPT value overshoots the holding temperature when reaching a temperature at which the test is held constant from the temperature rising state. Therefore, a test with excellent temperature controllability can be performed, and a weather resistance test result with excellent reproducibility can be obtained.

FIG. 1 is a block diagram of a weathering tester using a metal halide arc lamp according to the present invention as a light source 1. The weathering tester includes a test chamber 10, a light source 1 disposed in the test chamber 10, a spray nozzle 23 provided on one side of the light source 1, and a sample table disposed at a position 350 mm away from the light source 1. 6, a cooling coil 14, a heater 18, an inverter-controlled circulation blower 17, a control circuit that controls these devices, and a power source that drives these devices. The sample stage 6 is inclined obliquely so that the solution sprayed from the spray nozzle 23 does not stay, and the sample stage 6 has a light receiver 7, BPT 11, and a sample (not shown) attached thereto. Yes.

Next, the function is described according to the operation procedure. First, although not shown in the figure, after inputting test conditions (test chamber temperature: 63 ° C., relative humidity: 50%, etc.) to the test condition setting circuit, the weather resistance tester is turned on. Various signals for confirming the safety of the devices constituting the weather tester are transmitted to the apparatus abnormality detection circuit 2. If an abnormal signal is detected here, the abnormal part is displayed on the display 19 and the operation is stopped until the abnormality is canceled. Release at this time is performed manually.

When there is no abnormality or when the cause of the abnormality is removed and the abnormality is canceled, the light source 1 is turned on. Prior to the start of the test, the lighting voltage value and the current value obtained in advance from the average value of a plurality of light sources of the same type are stored in the irradiance control circuit 8, and these values are loaded on the light source 1 at the time of lighting. Therefore, a signal necessary for the operation is sent to the inverter type lighting power control circuit 3, and a signal indicating the lighting voltage is sent to the thyristor type lighting power output circuit 4 from here, and the light source 1 is automatically turned on.

After the lighting is confirmed, the inverter from the irradiance control circuit 8 based on the value of the irradiance from the light receiver 7 so that the value of the irradiance measured by the light receiver 7 becomes the irradiance of the preset test condition. A signal is sent to the mold lighting power control circuit 3. In this state, the weather resistance test is performed by controlling the irradiance of the light source 1.

FIG. 2 shows the change in the lighting voltage and the change in irradiance during the weather resistance test. FIG. 3 shows the same measurement results as in FIG. 2 when the conventional phase control type power supply is lit. As apparent from FIGS. 2 and 3, the voltage fluctuation of the lighting power supply and the change of irradiance are linked, and the fluctuation range of the irradiance under the condition of the present invention is the fluctuation of the irradiance under the condition of FIG. Very little compared to the width.

In a cycle test in which a light irradiation test, a darkness test, and a dew condensation test are repeated a plurality of times, at the same time as starting the light irradiation test, conventionally, in order to raise the value of BPT11 from room temperature to 63 ° C., the refrigerator is operated by PID control. At the same time, the heater 18 was activated and the electric power reaching 63 ° C. was loaded within 30 minutes (depending on the test conditions). Here, at the same time as the light irradiation test started, the refrigerator output control equipped with the PID control circuit The inverter control type refrigerator 13 is operated by the circuit 12, and in the temperature control arithmetic circuit 15, the heater 18 is stopped for 3 minutes after the start of lighting immediately before the irradiance of the light source starts to increase, and the irradiance of the lighting start light source After 3 minutes, the heater 18 is operated by the PID control circuit provided in the temperature control arithmetic circuit 15, and the value of BPT11 is 63 Control the start to be.

When the light irradiation test is completed and the process proceeds to the dark test and the dew condensation test, the lighting of the light source 1 is stopped.

FIG. 4 shows the value of BPT11 at the start of lighting, that is, until the value of BPT11 is stabilized at 63 ° C. from the room temperature state. FIG. 4 also shows the results when temperature control is performed under conventional control conditions. As shown in FIG. 4, the result of the present invention indicates that the temperature control is performed without overshooting the set temperature of 63 ° C.

It is a block diagram of a weathering tester using a metal halide arc lamp according to the present invention as a light source. It is a figure which shows the change of the lighting voltage and the change of irradiance which are implementing the weather test by the weather tester by this invention. It is a figure which shows the change of the lighting voltage and the change of irradiance when it lights with the conventional phase control type power supply and a weather resistance test is implemented. It is a figure which shows the value of BPT until the temperature in a test tank is stabilized from the lighting start.

Explanation of symbols

1 ... Light source
2 ... Device abnormality detection circuit
3. Inverter type lighting power control circuit
4 ... Thyristor type lighting power output circuit
5 ... Discharge power comparison circuit
6 ... Sample stand 7 ... Light receiver 8 ... Irradiance control circuit 9 ... Operation switch
10 ... Test tank 11 ... BPT
DESCRIPTION OF SYMBOLS 12 ... Refrigerator output control circuit 13 ... Inverter control type refrigerator 14 ... Cooling coil 15 ... Temperature control arithmetic circuit
16 ... Heater output circuit 17 ... Inverter-controlled circulation blower
18 ... Heater
19 ... Indicator 20 ... Humidifier

21 ... Temperature / humidity sensor 22 ... Optical filter 23 ... Spray nozzle

Claims (1)

A weathering tester having a light receiver mounted at the same position as the sample, a black panel thermometer, a temperature control arithmetic circuit, and a mechanism for controlling the temperature by a cooling coil connected to a heater and an inverter-controlled refrigerator. there, a mechanism for controlling the temperature, the value of the irradiance of the light source light source is measured by the light receiver after the lighting, until the start of the jump from the lighting start, without operating the heater the test was continued, the operates the first said heater when the value of the irradiance starts to spike, a temperature control signal calculated by the temperature control arithmetic circuit based on the transmitted value from the black panel thermometer A weathering tester characterized by controlling the temperature in the test tank .