JP2014163780A - Environmental resistance test method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method of controlling the temperature and humidity while efficiently removing the heat generation load, when a heat generation sample body of a large calorific value is disposed in an environmental test device.SOLUTION: An environmental test device includes: a test room that reserves humidified water in a pressure vessel and allows a sample body to be installed; and a heat exchanger for controlling the temperature of gas. When the gas temperature in the test room is increased by the heat generation load of the sample body, the calory is transferred out of the pressure vessel or out of a constant temperature and humidity tank via the heat exchanger to decrease the gas temperature. Thus, the temperature and humidity are controlled.

Description

The present invention relates to a temperature and humidity control method for a steam pressurization type environmental test apparatus used in reliability evaluation tests and environmental resistance tests of electrical parts, electronic parts and the like.

In order to perform reliability evaluation tests and environmental resistance tests of electrical parts, electronic parts and products assembled with these parts, the above parts etc. are exposed to environments with severe temperature and humidity, and operation check is performed. Various environmental test devices are used for the purpose of estimating the service life. As this type of environmental test apparatus, there is an environmental test apparatus capable of creating a high-temperature and high-humidity environment such as a highly accelerated life test apparatus (commonly referred to as a HAST apparatus).

In this highly accelerated life test apparatus, a test environment of atmospheric pressure or higher controlled by temperature and humidity is often formed in the test chamber. In this case, air is discharged and only the water vapor is present in the test chamber. The definition of humidity at this time is the ratio of the saturated vapor pressure between the humidified water temperature and the test chamber temperature.
Relative humidity% = (saturated water vapor pressure at humidified water temperature) / (saturated water vapor pressure at laboratory temperature) x 100 (1)

There are two types of high-acceleration life test equipment, one tank type and two tank type. The one-tank type is a type in which there are a humidified water section and a test chamber that generate water vapor in one pressure vessel, and the water vapor from the humidified water section is reheated by a heater and stirred by a blower. In the two-tank type, the humidifying water tank and the test chamber are separated from each other, and the humidifying water tank and the test chamber tank for generating water vapor are connected independently, and the water vapor generated in the humidifying water tank is supplied to the test chamber tank. This type is introduced and reheated with a heater.

When performing a test in a desired temperature and humidity environment in order to perform a reliability evaluation test and an environmental resistance test of a sample body installed in a test chamber of the environmental test apparatus using these environmental test apparatuses, If the heat generation load of the sample body is small or not even if the sample body is energized with respect to the ability to control the heating of the gas in the test chamber, the temperature and humidity can be controlled with respect to the set temperature and humidity.

However, using these environmental test equipment, if the heat generation load of the specimen installed in the test chamber is large, the temperature and humidity control is performed so that the temperature of the gas in the test chamber rises and maintains the set temperature. There is a problem that it cannot be done.

Therefore, it is necessary to cool the temperature of the gas in the test chamber to the set temperature.

Although not shown, in an environmental test apparatus that is not equipped with a cooler that is used in an atmospheric pressure environment, the gas temperature in the test chamber increases if the heat generation load of the sample body is greater than the cooling capacity by natural heat dissipation. However, by providing a cooling device such as a cooler, it is possible to cool and dehumidify the gas, and it is possible to control the temperature and humidity by suppressing an increase in the gas temperature in the test chamber due to the heat generation load of the sample body.

On the other hand, the advanced accelerated life test equipment is usually placed in a room temperature atmosphere of around 25 ° C, and the pressure vessel is used above the boiling point of water, that is, at 100 ° C or more. Therefore, heat transfer from the outer wall of the pressure vessel due to this temperature difference It is common to cool by using natural heat radiation by the heat sink, and it does not have a cooling device such as a cooler.

In this advanced accelerated life test apparatus, the air in the pressure vessel is exhausted and airtight, and the pressure in the pressure vessel is increased to increase the humidified water temperature to a saturated water vapor pressure corresponding to the humidified water temperature. The saturated water vapor is heated with a heater to create an environment of relative humidity% shown in the above equation (1). When the heat generation load of the sample body is larger than the cooling capacity by natural heat radiation, the gas temperature in the test chamber cannot be controlled by the heater and rises.

Therefore, a pressure vessel whose temperature and humidity are controlled by a method in which a cooler is installed as a cooling means on the outer wall surface of the pressure vessel of the advanced accelerated life test apparatus, or a method in which a cooler is installed as a cooling means in the pressure vessel. When trying to cool the gas inside, if the temperature of the cooler is lower than the humidified water temperature, the water vapor, which is a gas, is condensed and condensed at the surface of the cooler or at a temperature lower than the humidified water temperature. When water vapor condenses, it condenses instantaneously, so that there is a problem that the saturated water vapor pressure in the pressure vessel drops rapidly.

Therefore, the steam at the humidifying water temperature evaporates from the surface of the humidifying water to replenish the steam into the pressure vessel so that the saturated steam pressure corresponding to the humidifying water temperature is restored. The replenished water vapor is heated by the heating load of the heater and the sample body, and at the same time is cooled and condensed on the surface of the cooler. However, in the advanced accelerated life test apparatus in which cooling means are installed inside and outside the pressure vessel, the gas temperature and the humidified water temperature are controlled so as to reach the set temperature and humidity, but compared to sensible heat in which saturated steam is heated by a heater. However, the heat energy of the latent heat in which the water vapor evaporated from the humidified water is condensed by the cooler is much larger, and the gas temperature cannot be controlled.

JP 59-225336 A JP 62-269041 A JP 2011-252717 A

An object of the present invention is to provide a method for controlling temperature and humidity in a steam pressurization type environmental test apparatus while efficiently removing a temperature rise of a gas in a test chamber due to a heat generation load of a sample body installed in the test chamber. And

The means for solving the problems of the present invention is an environmental test apparatus comprising a sealable pressure vessel having a test chamber in which humidified water is stored and a sample body can be placed. A heat exchanger that can control the temperature of the water is provided, and a dry bulb temperature sensor and a humidified water temperature sensor or a wet bulb temperature sensor, or both a humidified water temperature sensor and a wet bulb temperature sensor are provided. When the gas temperature in the test chamber is higher than or is expected to be higher than the set temperature due to the heat generation load of the installed sample body, a heat medium or water above the humidified water temperature is passed through the heat exchanger, and the heat exchanger An object of the present invention is to provide a method for controlling the temperature and humidity in a test chamber by transferring the amount of heat of gas outside the pressure vessel without condensation on the outer surface.

Conventionally, when performing a test that generates a heat generation load on a specimen under a severe environment of test temperature (130, 120, 110 ° C) and test humidity (85%) using an advanced accelerated life test device (commonly called HAST device) Compared to the advanced accelerated life test of the technology, the heat load of the sample can be increased.

1 is a simplified cross-sectional view and a simplified configuration diagram of an environmental test apparatus in an embodiment of the present invention. It is the simplified sectional view and simplified structure figure of the environmental testing device in other embodiments of the present invention.

Embodiments of the present invention will be described below. FIG. 1 is a simplified cross-sectional view and a simplified configuration diagram of an environmental test apparatus that performs a highly accelerated life test by implementing the method for controlling temperature and humidity of the present invention.

An environmental test apparatus 1 that performs a highly accelerated life test of a simplified cross-sectional view and a simplified configuration diagram shown in FIG. 1 includes a pressure vessel 2 having an open end and an open / close lid 3 that can open and close the opening.

Inside the pressure vessel 2, an inner tank 4 that is open on the same side as the opening side of the pressure vessel 2 is installed, and a test chamber 5 is configured inside the inner vessel 4. Although not shown, the test chamber 5 is configured so that a sample body 13 can be placed by installing a shelf. The humidified water 9 is stored in the lower part outside the inner tank 4 inside the pressure vessel 2. A humidifying water heater 7 for heating the humidifying water 9 so as to be immersed in the humidifying water 9 and a humidifying water temperature sensor 12 for measuring the temperature of the humidifying water 9 are provided.

The test chamber 5 in the pressure vessel 2 is provided with a dry bulb temperature sensor 10 and a wet bulb temperature sensor 11 for measuring the temperature of the gas and the wet bulb temperature. The bulb portion of the wet bulb temperature sensor 11 is covered with a fibrous body that can suck up the humidified water 9 by capillary action, for example, gauze, and the lower end of the fibrous body is configured to be immersed in the humidified water 9. Further, a through-hole is formed on the side opposite to the opening side of the inner tank 4, and the gas is heated by the heater 6 installed between the inner tank 4 and the pressure vessel 2. The gas can be circulated by a stirring means.

A heat exchanger 8 is provided in the pressure vessel 2 so as to cool the gas heat by moving it. The heat exchanger 8 is preferably made of a material having a good heat conduction efficiency. In the simplified piping configuration of FIG. 1, a fluorine-based heat medium 15 having a high boiling point temperature is heated using a heater 16 inside a heat medium tank 14 installed outside the pressure vessel 2. The heated heat medium 15 is connected to one end of the heat exchanger 8 via a circulation pump 17 as a flow rate inlet, and the other end is connected to the heat medium tank 14 via a radiator 19 as a flow rate outlet. It is configured as a return piping system. Further, in order to control the temperature of the heat medium 15, an auxiliary heater 18 and temperature sensors 20, 21, and 22 are provided.

Further, the pressure vessel 2 is provided with a control valve 23 for making the inside of the pressure vessel 2 airtight at atmospheric pressure or higher. The environmental test apparatus 1 of FIG. 1 includes a control device (not shown), and the environmental test device 1 is controlled by this control device.

In the above configuration, as a representative set temperature and humidity example of the embodiment, a set value example of a set temperature of 130 ° C. and a set humidity of 85% will be described.

After placing the sample body 13 in the test chamber 5, boiling the humidified water 9 to 100 ° C., discharging the air in the pressure vessel 2 to make only water vapor, and closing the control valve 23 to make the pressure vessel 2 airtight. If the environment of the test chamber 5 reaches a set temperature of 130 ° C and a set humidity of 85% and is stable by further heating, the temperature of the dry bulb temperature sensor 10 corresponding to the test chamber temperature of the equation (1) is The temperature of the humidified water temperature sensor 12 corresponding to the humidified water temperature of 130 ° C. is about 124.65 ° C. (saturated water vapor pressure converted to 0.2296 MPa, from the Japan Society of Mechanical Engineers steam table). At this time, the temperature of the bulb portion of the wet bulb temperature sensor 11 is empirically regarded as the same value as the temperature of the humidified water temperature sensor 12 if the fibrous body of the bulb portion is sucked up by the capillary phenomenon from the humidified water and is wet. Can do.

If the sample body 13 in the test chamber 5 does not generate heat, in the simplified piping configuration of FIG. 1, a control valve (not shown) between the circulation pump 17 and the heat exchanger 8 is closed, the circulation pump 17 is stopped, and the heat medium 15 is heated. Since it is stagnant in the exchanger 8, the measured temperatures of the temperature sensor 21 and the temperature sensor 22 are equal and equal.

In the pressure vessel 2 at this time, water vapor evaporated from the surface of the humidified water 9 at about 124.65 ° C. is heated by the heater 6 to control the gas (water vapor) temperature in the test chamber 5 to 130 ° C. In other words, to maintain the environment in which the non-heated sample body 13 is placed in the test chamber 5 at the set temperature 130 ° C. and the set humidity 85%, the humidified water 9 is set to about 124.65 ° C. and the gas in the test chamber 5 Is heated at about 5.35 ° C. by the heater 6 and maintained at 130 ° C.

Here, when the sample body 13 is energized, the sample body 13 generates heat and starts to warm the temperature of the gas. Then, the heat generation amount of the heater 6 is decreased in accordance with the heat generation amount of the sample body 13, and the temperature of the gas in the test chamber 5 is controlled to be constant. However, when the calorific value generated by the sample 13 becomes a calorific value that heats the gas in the test chamber 5 by about 5.35 ° C. or more, the gas temperature in the test chamber 5 is 130 ° C. even if the energization amount of the heater 6 is 0%. As a result, the set temperature of 130 ° C and the set humidity of 85% cannot be maintained. The allowable heat generation load of the sample body 13 when performing an environmental test at a set temperature of 130 ° C. and a set humidity of 85% with an environmental test device that performs an advanced accelerated life test without carrying out the present invention is approximately 5.35 ° C. for the gas in the test chamber 5 That is, it is equal to or less than the amount of heat generated by the heater 6 required to rise.

Next, in the embodiment of the present invention, when an environmental test is performed at a set temperature of 130 ° C. and a set humidity of 85%, the case where the sample body 13 generates heat exceeding the allowable heat generation load will be described.

When the environment of the test chamber 5 is stable at a set temperature of 130 ° C. and a set humidity of 85%, the heat medium 15 of the fluorinated heat transfer oil in the heat medium tank 14 is heated to about 124.65 ° C. or more and less than 130 ° C. Control to temperature. Next, the control valve (not shown) is opened to drive the circulation pump 17. The circulation pump 17 is configured so that the flow rate of the heat medium 15 can be adjusted by controlling the rotation. The circulation pump 17 controls the rotation so that the measured temperature of the temperature sensor 21 is about 124.65 ° C. or higher and lower than 130 ° C., and the measured temperature of the temperature sensor 22 at the outlet is 130 ° C. The liquid is sent to the inlet portion of one end of the heat exchanger 8 in the pressure vessel 2 by the circulation pump 17. The temperature of the heat medium 15 is mainly adjusted in the heat medium tank 14, and the set temperature is set to about 124.65 ° C. or more and less than 130 ° C. in consideration of the rising temperature of the gas in the test chamber 5 due to the heat generation load of the sample body 13. . If the measured temperature of the heat medium 15 of the temperature sensor 21 installed at the inlet of the heat exchanger 8 is measured or predicted to be lower than about 124.65 ° C due to heat radiation from the pipe during liquid feeding, the auxiliary heater 18 Warm above the humidified water temperature.

At first, the surface of the heat exchanger 8 in the pressure vessel 2 is exposed to the temperature of the gas (water vapor) in the pressure vessel 2 and is therefore 130 ° C. When the heat medium 15 of about 124.65 ° C. or more and less than 130 ° C. flows through the heat exchanger 8, the heat quantity of the gas (water vapor) in the pressure vessel 2 is transferred without condensation in the heat exchanger 8, and further, the heat medium Heat is transferred to 15, the temperature of the heat medium 15 is raised, and the heat is exchanged out of the pressure vessel 2 and discharged. When the heat medium 15 flows through the heat exchanger 8, the measured temperature of the temperature sensor 21 at the inlet and the measured temperature of the temperature sensor 22 at the outlet are (measured temperature of the temperature sensor 21) <(measured temperature of the temperature sensor 22). ) Relationship occurs.

Here, when the environment of the test chamber 5 is stable at a set temperature of 130 ° C. and a set humidity of 85%, and a heat generation load of a calorific value that raises the gas in the test chamber 5 by 10 ° C. is applied to the sample body 13, the heater Even if the energization amount of 6 is 0%, the temperature of the gas in the test chamber 5 becomes 134.65 ° C. (124.65 ° C. + 10 ° C.), which is + 4.65 ° C. higher. To set the temperature of the gas in the test chamber 5 to 130 ° C., heat the circulation pump 17 so that the measurement temperature of the temperature sensor 21 of the heat exchanger 8 is 125.35 ° C. and the measurement temperature of the temperature sensor 22 at the outlet is 130 ° C. The flow rate of the medium 15 is controlled to rotate. The heat medium 15 coming out of the heat exchanger 8 is cooled by the radiator 19 so as to be equal to or lower than the temperature measured by the temperature sensor 21 and returned to the heat medium tank 14. Then, the temperature is adjusted again in the heat medium tank 14 so that the temperature measured by the temperature sensor 21 of the heat exchanger 8 becomes 125.35 ° C., and the circulation pump 17 rotates and circulates the flow rate of the heat medium 15.

Alternatively, the temperature of the heat medium 15 is adjusted in the heat medium tank 14 so that the measurement temperature of the temperature sensor 21 of the heat exchanger 8 is 124.65 ° C. or more and the measurement temperature of the temperature sensor 22 of the outlet is less than 130 ° C., and the circulation pump 17 Thus, the flow rate of the heat medium 15 is rotationally controlled. The heat medium 15 coming out of the heat exchanger 8 is cooled by the radiator 19 so as to be equal to or lower than the temperature measured by the temperature sensor 21 and returned to the heat medium tank 14. At this time, the temperature corresponding to 0.7 ° C. (125.35 ° C.-124.65 ° C.) corresponding to the exchange heat amount of the heat exchanger 8 that has been overcooled in the test chamber 5 may be compensated by the energization amount of the heater 6.

Next, when a heat generation load of a heat generation amount that raises the gas in the test chamber 5 by 20 ° C. is applied to the sample body 13, the gas temperature in the test chamber 5 is 144.65 even if the energization amount of the heater 6 is 0%. It becomes ℃ (124.65 ℃ +20 ℃) and increases by +14.65 ℃. In order to set the temperature of the gas in the test chamber 5 to 130 ° C., the circulation pump 17 is set so that the measurement temperature of the temperature sensor 21 of the heat exchanger 8 is 124.65 ° C. or more and the measurement temperature of the temperature sensor 22 at the outlet is less than 130 ° C. Then, the flow rate of the heat medium 15 is increased to control the rotation, and after cooling through the radiator 19, the temperature of the heat medium 15 is adjusted in the heat medium tank 14.

Furthermore, when a heat generation load with a heat generation amount that raises the temperature of the gas in the test chamber 5 is applied to the sample body 13, the heat medium 15 is newly replaced with a heat medium with a good specific heat, and the heat transfer area is large and the heat exchange capacity is large. Replace with a good heat exchanger 8, replace with a circulation pump 17 with a large circulation flow rate, replace with a radiator 19 with a large heat transfer area and good exchange heat, or air-cool the radiator 19 with a fan (not shown). It is possible to suppress the rise in the temperature of the gas in the test chamber 5 by moving the calorific value outside the pressure vessel 2.

In FIG. 1 in which claim 1 of the present invention is implemented, the heat medium tank 14, the heat medium 15, the heater 16, and the temperature sensor 20 are installed outside the pressure vessel 2, but the simplified example of FIG. As shown in the configuration diagram, the humidified water 9 in the pressure vessel 2 may be connected by piping so that it can be used as a heat medium.

Further, in the environmental test apparatus constituted by the sealable pressure vessel having the test chamber in which the humidified water is stored and the sample body can be installed, in which the present invention of claim 1 is implemented, the test chamber 5 If the temperature of the heat medium 15 in the heat exchanger 8 is made to flow at a temperature equal to or higher than the set temperature of the test chamber 5, the temperature of the gas in the test chamber 5 will be the surface of the heat exchanger 8. The temperature rises. The gaseous water vapor can be heated by the heat quantity of the heat medium 15 in the heat exchanger 8 in addition to the heater 6 in the pressure vessel 2. Therefore, as compared with the conventional environmental test apparatus that performs the advanced accelerated life test, the environmental test apparatus that implements the present invention can be used to increase the temperature in the pressure vessel 2 in a short time.

The present invention enables a life test and a high-temperature and high-humidity bias test to be performed in an operating state by applying a voltage / current to more electrical parts and electronic parts in an environment where the temperature and humidity are severe. It can be advantageously used in industries that perform evaluation tests and environmental resistance tests.

・ Environmental test equipment ・ Pressure vessel ・ Lid ・ Inner tank ・ Test room ・ Heating heater ・ Humidification water heater ・ Heat exchanger ・ Humidification water ・ Dry bulb temperature sensor ・ Wet bulb temperature sensor ・ Humidification water temperature sensor ・ Specimen ・ Heat Medium tank ・ Heat medium ・ Heater ・ Circulation pump ・ Auxiliary heater ・ Radiator
20, 21, 22 Temperature sensor
23 Control valve

Claims (1)

In an environmental test apparatus composed of a sealable pressure vessel having a test chamber in which humidified water can be stored and a sample body can be placed, a heat exchanger capable of controlling the temperature of the gas is provided in the pressure vessel. A sample installed in the test chamber, provided with a dry bulb temperature sensor and a humidified water temperature sensor or a wet bulb temperature sensor, or both a dry temperature bulb sensor, a humidified water temperature sensor and a wet bulb temperature sensor. When the gas temperature in the test room is higher than the set temperature or is expected due to the heat generation load of the body, the heat exchanger passing the heat medium higher than the humidified water temperature or the water higher than the humidified water temperature is passed through the heat exchanger. A method of controlling the temperature and humidity in the test chamber by moving the amount of gas heat outside this pressure vessel without condensation on the outer surface of the test chamber.