JPH04320946A - Air tank type heat shock tester - Google Patents

Abstract

PURPOSE:To easily and simply hold the set temp. of low temp. exposure in a heat shock test by a method wherein the measured value of a temp. sensor is compared with the set temp. value of low temp. exposure and, when the measured value is low, a regenerator damper is operated to reduce the operation frequency of a cooler. CONSTITUTION:An apparatus is divided into a high temp. chamber 2, a test chamber 1 and a low temp. chamber 3 and air flows by appropriately controlling the opening and closing of dampers 4-9 and a regenerator damper 20 constitutes an avoiding means. A low temp. exposure set value is compared with the temp. measured value in the test chamber 1 and, when the set value is lower than the measured value, a cooler 16 is operated as it is to automatically cool the test chamber 1. When the set value is higher than the measured value, the damper 20 is closed and the cooling heat formed in the cooler 16 flows to the test chamber 16 and returns to the cooler 16 without passing through a regenerator 18. When the measured value is still low even when the operation frequency of the cooler 16 is reduced to the min. frequency in this state, a command is issued to open the damper 20 to hold required set temp.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an air chamber thermal shock testing apparatus, and more particularly to the air chamber thermal shock testing apparatus which realizes temperature control during low-temperature exposure at low cost.

0002

[Prior Art] An air tank type thermal shock test device is used to test the characteristics of electrical and electronic components against thermal shock.
It consists of a high-temperature chamber that generates high-temperature air and a cold chamber that generates low-temperature air.The test consists of high-temperature exposure while circulating high-temperature air from the high-temperature chamber to the test chamber, and high-temperature exposure while circulating low-temperature air from the low-temperature chamber. Low-temperature exposure and low-temperature exposure are repeated while being circulated through the test chamber.

[0003] At this time, the temperature of high temperature exposure is, for example, 10
0°C, and the temperature of low-temperature exposure is, for example, -50°C. By the way, when repeating high-temperature exposure and low-temperature exposure at extremely different temperatures like this, in order to improve the efficiency of the test, for example, when switching from high-temperature exposure to low-temperature exposure, it is necessary to spend a lot of time in the test room at the initial stage. It is necessary to rapidly cool down the test chamber, which was previously at a high temperature, by sending a large amount of cooling heat all at once.

[0004] As a means for this purpose, conventionally, a cold storage device is installed together with a cooler in a low temperature room, and during high temperature exposure, the cooling heat of the cooler is stored in the cold storage device, and at the same time as the low temperature exposure is switched, this cold storage cooling is carried out. The heat was sent to the test chamber along with the cooling heat generated by the cooler.

However, in this case, there is a limit to the cold storage capacity of the regenerator, and even if the cool storage cooling heat is initially radiated and contributes to cooling the test chamber, the test chamber may not reach the required set low temperature exposure temperature. By then, all of the stored cooling heat has been radiated, and after that it becomes a negative load on the test room cooling, and even causes a delay in cooling the test room to the set temperature. Therefore, the applicant:
After considering the above-mentioned problems, we found that, when the regenerator has finished dissipating the stored cooling heat or is about to dissipate the heat, an avoidance method has been developed to avoid the regenerator from the low-temperature airflow circulating between the test chamber and the cold room. , we found that it is effective to install it in a cold room and proposed it earlier. (Special application Hei 2
-50418) As a specific example of this avoidance means, a regenerator damper that opens and closes the air inflow of the regenerator is mainly applied, and when the regenerator damper operates and closes the inlet side of the regenerator, the test chamber The low temperature air that returned to the cold room
The airflow is switched from flowing to the cooler via the regenerator to airflow bypassing the regenerator and directly returning to the cooler. As a result, the above-mentioned reverse load is eliminated until the conventional low-temperature exposure setting temperature is reached, and when switching from high-temperature exposure, the low-temperature exposure setting temperature can be reached in an extremely short period of time, allowing for thermal shock testing. We were able to achieve efficiency.

However, regarding low-temperature exposure, another problem arose: how to maintain and control the temperature in the test chamber once it reached the set temperature. Even with the thermal shock test device proposed earlier by the present applicant, even if the test chamber is efficiently cooled down to the set temperature in a short period of time using the avoidance means, if left as is, the test chamber will Although the temperature was lowered by the action of the cooler, a normal low-temperature exposure test was no longer possible. By the way, various types of control means for maintaining the set temperature during low-temperature exposure have been proposed, such as one using a reverse load heater, one using capacity control of a refrigerator attached to a cooler, and the method described in Japanese Patent Application Laid-Open No. 1983-1989. 1252
As described in Japanese Patent Application No. 33, there is a system that maintains a set temperature by controlling the evaporation temperature of the cooler using a hot gas bypass of the refrigerator. Therefore, in order to solve the above-mentioned problem, the thermal shock test apparatus proposed by the present applicant also needs to be equipped with one of these temperature maintenance control means.

[0007]

[Problems to be Solved by the Invention] However, each of the above-mentioned set temperature holding means, for example, one using a reverse load heater or the capacity control of a refrigerator is preferable because it is simple and has an energy saving effect. Depending on the set temperature, there may be an inconvenience in not being able to control it, or especially when capacity control is used, there is a limit to increasing the temperature of the cooling heat generated by the cooler even if the operating frequency of the refrigerator is lowered, and the set temperature may be -30 When the temperature is relatively high, such as ℃, it is difficult to control.

On the other hand, the hot gas bypass method
It is possible to maintain and control the temperature at any set temperature, but unless piping for hot gas bypass is provided to the cooler and a solenoid valve is installed to allow hot gas to flow appropriately to the piping. Not,
Since the solenoid valve is expensive, there is a problem in that the cost of the entire device increases.

In view of the above-mentioned circumstances, the present invention aims to reduce the set temperature for low-temperature exposure in an air tank type thermal shock testing apparatus equipped with the air flow avoidance means by specifically opening and closing the damper of the regenerator. Moreover, the purpose is to easily and simply control the holding of any set temperature.

0010

[Means for Solving the Problems] That is, the features of the present invention that meet the above object include a low temperature chamber, a high temperature chamber, and a test chamber, and a cooler is disposed in the low temperature chamber. On the other hand, a regenerator is arranged on the upstream side of the airflow flowing through the cold room to enable cold storage when exposed to high temperatures, and an avoidance means is provided to avoid the regenerator from the airflow flowing through the cold room when exposed to low temperatures. , a detection means for detecting and outputting the end or near end of heat radiation of the amount of cooling heat stored in the regenerator, and when exposed to low temperature, the output from the detection means operates the avoidance means, and the airflow flowing through the cold room is activated. and a controller for switching the airflow to bypass the regenerator, the cooler is capable of being controlled by an inverter, and a temperature sensor is arranged in the test chamber, and the temperature means for comparing the measured value of the sensor and a set temperature value for low-temperature exposure, and after operating the avoidance means when the measured value is lower than the set temperature value as a result of the comparison by the comparing means;
means for reducing the operating frequency of the cooler; and stopping the operation of the avoidance means when the measured value is still lower than the set temperature value even after the reducing means reduces the operating frequency of the cooler to the lowest frequency. The present invention is characterized in that the controller is provided with means for causing the above-mentioned.

[0011]

[Operation] According to the present invention, the temperature of the test chamber which has reached the set temperature is maintained at a constant temperature in the following manner. That is, the controller constantly compares the test room temperature sent from the temperature sensor with the set temperature, and if the actual temperature is higher than the set temperature, it activates the avoidance means. Let the cooler continue to operate as it is,
Try to lower the temperature in the test room.

On the other hand, as a result of the comparison, if the actual temperature in the test chamber is lower than the set temperature, the controller instructs the refrigerator that operates the cooler to reduce the operating frequency, thereby reducing the cooling frequency. This reduces the amount of cooling heat generated by the chamber and increases the temperature inside the test chamber. However, even if the operating frequency is lowered to the lowest frequency, the temperature in the test chamber may still be below the set value. At this time, the controller
The avoidance means is deactivated and the regenerator is placed in the airflow circulating between the cold room and the test chamber. Then, since the regenerator is subjected to a reverse load when cooling the test chamber, the temperature of the test chamber will rise again. The set temperature maintenance control during low temperature exposure in the present invention is performed by appropriately operating the cooler and avoidance means as described above.

[0013]

Embodiments Hereinafter, embodiments of the present invention will be further described based on the drawings. FIG. 1 is a sectional view showing an example of the air tank type thermal shock test apparatus according to the present invention. It is divided into three rooms (3). And each room (
1), (2), and (3) are divided by heat insulating partition walls (W) and (W), and each heat insulating partition wall (W) and (W) is equipped with an opening/closing damper (4) and (5). Supply ports (10), (1
1), opening/closing dampers (6), (7), and partition dampers (8).
), (9) are provided, and by appropriately opening and closing these dampers (4) to (9), the high temperature chamber (2) and the test chamber (1 ), or air can circulate between the low temperature chamber (3) and the test chamber (1) (see FIGS. 5 and 4).

[0014] The high-temperature room (2) has a heater (14) and a heating fan (15) installed therein, and generates heated air of, for example, about 100°C, and directs the heated air to the air outlet. (12) and the test chamber (through the supply port (10)).
1) Can be supplied in circulation. Note that (M1) located outside the high temperature room (2) is a drive motor for rotating the heating fan (15).

On the other hand, inside the cold room (3), there is a cooler (1).
6), a cooling fan (17), and a regenerator (18) are arranged. In this case too, it is located outside the cold room (3) (M
2) is a drive motor that rotates the cooling fan (17). The cooler (16) is connected to a capacity-controllable refrigerator (not shown) installed outdoors. The output temperature can be changed to, for example, about -40°C to -60°C. Also,
The regenerator (18) is fixed in the cold room (3) in a state in which it is hung diagonally from the upper end of the side wall of the cold room (3), and the side facing the cooler (16) is the air inflow side. (18
A), the opposite side is the air outflow side (18B). Regarding this regenerator (18), the upper end portion of the air inflow side (18A) is further closed by a closing plate (19), and the lower part thereof is a cross section that rotates around the lower end of the air inflow side (18A) as a fulcrum. It is opened and closed by an inverted dogleg-shaped regenerator damper (20).

By the way, the regenerator damper (20) constitutes the avoidance means in the above-mentioned invention, and the upper part (20) of the damper (20) bent in an inverted dogleg shape (
20A) closes the air inflow side (18A) of the regenerator (18), the lowest end of the lower part (20B) closes the cold room (3
), and this is when the avoidance means is activated, against the low-temperature air flowing from the test chamber (1) through the supply port (11) and back into the cold room (3). , the flow is made to bypass the regenerator (18) (see FIG. 3). In addition, when the upper part (20A) of the regenerator damper (20) is separated from the regenerator (18) and opens the air inflow side (18A) of the regenerator (18), the upper end of the upper part (20A) comes into contact with the upper end of the cooler (16), and the lower part (20B) is in contact with the lower surface of the regenerator (18) (see FIGS. 4 and 5), and when the avoidance means stops operating, the supply port (11) and then in a cold room (
3) and the airflow circulating inside the cold room (3) from the air inflow side (18A) to the air outflow side (18A).
B), passing through the regenerator (18) and passing through the cooler (1
By returning to step 6), the regenerator (18) can be used as before.

In this case, the regenerator damper (20
) was used to expose the test chamber (1) to a low temperature and cool it down to the set temperature as follows. First, Figure 5 shows
This figure shows an air tank type thermal shock test apparatus during high temperature exposure and cold storage. On the high temperature chamber (2) side, the opening/closing dampers (4), (6) and the partition damper (8) are all open, and high temperature air is sent to the test chamber (1) and the air is placed in the test chamber (1). Electrical and electronic components (not shown) have been tested against high heat.
On the other hand, on the cold room (3) side, the opening/closing dampers (5) and (7)
) and the partition damper (9) are all in a closed state,
The cooler (16) and the cooling fan (17) are driven,
The cooling heat generated by the cooler (16) circulates within the cold room (3), and the regenerator (18) is located in the circulating airflow with the regenerator damper (20) open. Cooling heat generated by the cooler (16) is stored in the regenerator (18).

Next, when the high temperature exposure ends, the cool storage operation ends, and as shown in FIG.
), (7), and (9) are opened, the cooling heat of the cooler (16) and the stored cooling heat of the regenerator (18) are supplied to the test chamber (1) along with the operation of the cooling fan (17). As a result, the test chamber (1), which has been heated up to now, is cooled to the set temperature at which low-temperature exposure should be performed. At this time, the regenerator (18
), when all or almost all of the heat is radiated, the regenerator damper (20)
8) to the air inlet side (18) of the regenerator (18).
A) is closed, and the low-temperature airflow circulating between the cold room (3) and the test chamber (1) is switched to a flow that bypasses the regenerator (18) (see Figure 3), whereby the regenerator (18) To efficiently cool a test chamber (1) to a set temperature by preventing a reverse load. In order to operate the regenerator damper (20) as described above, as shown in FIG. 21), and the regenerator (18) temperature sensor (21) and the drive motor (M3) of the regenerator damper (20) are connected to a controller (22), respectively, and the drive motor (M3)
This is performed by appropriately driving the regenerator temperature sensor (21) based on the detected value of the regenerator temperature sensor (21).

In the present invention, the regenerator damper (20) is utilized thereafter in order to maintain and control the temperature of the low-temperature exposure that has reached the set temperature at a constant temperature. In FIG. 1, (23) located inside the test chamber (1) indicates a temperature sensor that measures the temperature inside the test chamber (1). The measured value of this temperature sensor (23) is input to the controller (22). Further, the low temperature exposure setting temperature is also input to this controller (22). And the controller (22) is
The set temperature during low temperature exposure can be maintained and controlled according to the flowchart shown in FIG. In FIG. 2, initially, at the time of start (A), the regenerator damper (20) is closed toward the air inlet side (18A) of the regenerator (18), and the controller (22) is not able to measure time by the timer. This timing is started (b) in order to advance the control cycle described below by each count, for example, with -10 seconds as one count.

Next, the low temperature exposure setting value (SP) is compared with the temperature measurement value (MT) in the test chamber (1) sent from the temperature sensor (23) in the test chamber (1). (c). At this time, if the set value (SP) is lower than the measured value (MT), the cooler (16) is left in operation. As a result, the inside of the test chamber (1) is naturally cooled,
Eventually, the measured value (MT) becomes equal to or less than the set value (SP).

On the other hand, in the comparison in (c), the set value (S
When P) is greater than or equal to the measured value (MT), it is first confirmed that the regenerator damper (20) is closed. Of course, in this case,
The regenerator damper (20) is closed from the beginning, so it can be left closed as is, but if it is open during the process of repeating the process, it will be closed at this point (d). The closed state of the regenerator damper (20) is shown in FIG. 3, and the cooling heat generated by the cooler (16) is transferred to the cooling fan (1).
7), it passes through the outlet (13), flows through the test chamber (1), and returns to the cooler (16) from the supply outlet (11) without passing through the regenerator (18). And in this state, the cooler (
It is checked whether the refrigerator for operating the cooler (16) is being operated at the lowest frequency (e), and if it is not the lowest frequency, the frequency is decreased by, for example, 10 Hz (f), and the refrigerator (16) is operated at the lowest frequency. ), and after increasing the temperature of the test chamber (1), confirming that the time measurement by the time measurement means has advanced by one count (g), and one control cycle is completed. Return to the original.

Since such a control cycle is repeated during the low temperature exposure, as long as the measured value (MT) in the test chamber (1) is below the set value (SP), the frequency is decreased by one count and the test The temperature in the chamber (1) will gradually rise, but even if the frequency is lowered to the lowest frequency at which the refrigerator can be operated (for example, 30 Hz), the set value (S
When P) is greater than or equal to the measured value (MT), the controller (
22) is the regenerator damper (20) which has been closed until now.
Issue an opening command to (H). This regenerator damper (2
0) is open as shown in Figure 4, and the cooler (1
The cooling heat generated in step 8) flows from the air outlet (13) to the test chamber (1) on the airflow generated by the cooling fan (17), cools the inside of the test chamber (1), and then flows to the supply port (11). After returning to the cold room (3), the air passes through the regenerator (18) from the air inflow side (18A) to the air outflow side (18B) and enters the cooler (
Repeat the cycle returning to step 16). As a result, the regenerator (18), which has already finished dissipating the stored heat, now becomes a reverse load on the cooler (16), increasing the cooling temperature of the test chamber (1) by that amount. The above is the explanation of the flowchart shown in FIG. During the low-temperature exposure, the temperature in the test chamber (1) is maintained at the desired set temperature by repeating the control cycle according to the above-described flow chart.

[0023] In the above embodiments, the regenerator damper (20), which is the avoidance means, is particularly
8) is fixed to the upper part of the side wall of the low temperature chamber (3) in a diagonal manner as described above, and therefore, as mentioned above, the inverted part is divided into an upper part (20A) and a lower part (20B). This regenerator damper (
Regarding 20), it is important to be able to switch the airflow flowing through the cold room (3) to an airflow that bypasses the regenerator (18), and therefore, the present applicant has proposed the above-mentioned patent application No. 2-5041.
As shown in Publication No. 8, depending on the shape and installation position of the regenerator (18) in the cold room (3), the regenerator damper (
The shape of 20) and its operation mode may be changed as appropriate. Also, as described in the above publication, in some cases, the regenerator damper (20) may not be provided.
The present invention may be constructed by making the regenerator (18) itself movable outside the airflow flowing through the cold room (3) and using this as an avoidance means.

[0024]

Effects of the Invention As explained above, the present invention allows low-temperature airflow circulating between the cold room and the test room to pass through the regenerator when the regenerator has finished discharging the stored cooling heat or is nearing the end of its heat dissipation. This is an air tank type thermal shock testing apparatus equipped with an avoidance means capable of switching from a flow to a flow that bypasses a regenerator, the avoidance means being used as a temperature maintenance control means during continued low temperature exposure, and the above-mentioned means for comparing the temperature measurement value in the test chamber with the set temperature value of the low temperature exposure for the controller that activates the avoidance means; means for reducing the operating frequency of the cooler after operating the avoidance means; and even if the reducing means reduces the operating frequency of the cooler to the lowest frequency, the measured value is still lower than the set temperature value. Therefore, the maintenance control of the low temperature exposure set temperature is performed by controlling the capacity of the refrigerator and by causing the regenerator to stop the operation of the test room cooling by the avoidance means. This can be achieved by the combined action of the capacitor and the capacitance, making it possible to control temperature ranges that could not be controlled by capacitance control alone. And in that case, conventionally,
Of course, the reverse load heater and hot gas solenoid valve that were used as the set temperature maintenance control means are no longer required, and the cost of the entire device can be reduced, and the temperature can be maintained for any set temperature. It becomes easier to control.

As described above, the present invention enables the above-mentioned avoidance means to be effectively used as a set temperature maintenance control means for low-temperature exposure. Since the low-temperature exposure in the thermal shock testing apparatus of the present invention enables the set temperature to be reached quickly, in the gas tank-type thermal shock testing apparatus of the present invention, from the time the high-temperature exposure is switched to the low-temperature exposure, the next low-temperature exposure is performed. The avoidance means can be consistently used as a temperature control means for low-temperature exposure until the point of switching to high-temperature exposure, making temperature control efficient throughout the entire low-temperature exposure test in the air chamber thermal shock test equipment. And it can be done at low cost.

[Brief explanation of drawings]

FIG. 1 is a longitudinal cross-sectional view of an air tank type thermal shock testing apparatus according to the present invention.

FIG. 2 is a process flowchart for maintaining and controlling the set temperature during low-temperature exposure in the air tank type thermal shock testing apparatus according to the present invention.

FIG. 3 is a partial cross-sectional view illustrating a test mode using the air tank type thermal shock test apparatus.

FIG. 4 is a partial cross-sectional view illustrating a test mode using the air tank type thermal shock test apparatus.

FIG. 5 is a partial cross-sectional view illustrating a test mode using the air tank type thermal shock test apparatus.

[Explanation of symbols]

(1) Test chamber (2) High temperature room (3) Low temperature room (16) Cooler (18) Cold storage (20) Cold storage damper (21) Cold storage temperature sensor (detection means) (22)
Controller (23) Temperature sensor

Claims (1)

[Claims] 1. A test chamber (1) comprising a low temperature chamber (3), a high temperature chamber (2), and a test chamber (1), and a cooler (1) in the low temperature chamber (3).
At the same time, a regenerator (18) is disposed on the upstream side of the airflow flowing through the low temperature chamber (3) with respect to the cooler (16) to enable cold storage when exposed to high temperatures. 18) is provided with an avoidance means (20) that avoids the airflow flowing through the cold room (3) when exposed to low temperatures, and detects the end of heat radiation or near the end of the amount of cooling heat stored in the regenerator (18). detection means (21) for outputting
During low temperature exposure, the avoidance means (18) is activated by the output from the detection means (21), and the low temperature chamber (3)
a controller (22) for switching an airflow flowing through the regenerator (18) to an airflow bypassing the regenerator (18), the cooler (16) being capable of being controlled by an inverter; A temperature sensor (23) is arranged in the test chamber (1), a means for comparing the measured value of the temperature sensor (23) and a set temperature value for low-temperature exposure, and a measured value as a result of the comparison by the comparing means. is lower than the set temperature value, the avoidance means (20)
means for reducing the operating frequency of the cooler (16) after operating the cooler (16);
When the measured value is still lower than the set temperature value even if the operating frequency of the avoidance means (20
) for stopping the operation of the controller (22).
) An air tank type thermal shock testing device characterized by comprising: