JP6735703B2 - Environmental test equipment and environmental test method - Google Patents

Description

The present invention relates to an environmental test device that adjusts a temperature and humidity in a test chamber to a target temperature, and particularly relates to an environmental test device that can perform an icing test to test performance and the like by icing an object to be tested. It is a thing.
The present invention also relates to an ice accretion test method.

Environmental testing is one of the methods for testing the performance and durability of products and equipment. The environmental test is a test for examining the performance and durability of the DUT under a specific environment.
The environmental test device is a device developed to perform an environmental test, has a test chamber in which the DUT is placed, and has a function of adjusting the temperature and humidity in the test chamber to a desired test environment. ing. Patent Documents 1 and 2 disclose representative environmental test devices.

An ice test is one of the environmental tests. The icing test is to generate frost and ice on the surface of the test object.
Patent Document 3 discloses an environmental test method in which low-temperature air is blown onto a test object to lower the temperature, and then high-humidity air is introduced into a test chamber to cause dew condensation or frost formation on the surface of the test object. And a device are disclosed.

JP, 2016-102681, A JP, 2016-176793, A JP, 2016-90482, A

As one of the environmental tests using an aircraft as a test object, there is an icing test assuming a situation in which the aircraft passes through clouds.
For the icing test, for example, the following steps are sequentially performed.
(1) The test room is set to a low temperature environment, and the test object is exposed to it.
(2) Depressurize the test chamber.
(3) Humidify the inside of the test chamber to allow water vapor to condense and freeze on the surface of the DUT.

The present inventors can perform an icing test by using an environmental test device that has a function of adjusting the temperature and humidity in the test chamber to a desired test environment and that can depressurize the test chamber. I thought I could do it. That is, the inventors of the present invention considered that the ice accretion test can be carried out by using an environment test apparatus having a normal air conditioning function and capable of reducing the pressure.

However, when the inventors of the present invention conducted the above-mentioned icing test using an ordinary environment test device, there were cases where unexpected problems occurred.
That is, when the above-described icing test was carried out with the environment test device having the conventional structure, icing was extensively formed on the inner wall of the test chamber, and the icing on the test object, which is important, was unexpectedly small in some cases.
When this problem was examined, it was assumed that one of the causes was that the relationship between the volume of the test chamber and the heat capacity of the DUT was unbalanced.
That is, if the volume of the test chamber is of a size commensurate with the heat capacity of the DUT, the humidified air can greatly contribute to the icing of the DUT and cause the desired icing of the DUT. It is supposed to be possible.

On the other hand, if the volume of the test chamber is excessively large with respect to the heat capacity of the DUT, the humidified air is consumed for icing on the walls of the test chamber, and the icing on the DUT becomes relatively small. Expected to end.
Although it is considered that ideal icing can be generated on each DUT by preparing environmental test devices of multiple sizes according to the size of the DUT, it is possible to use environmental test devices of different sizes. It is often difficult to prepare a plurality of units due to economic restrictions and restrictions on installation locations.

It is an object of the present invention to provide an environmental test method and an environmental test apparatus capable of suppressing wasteful icing, focusing on the above-mentioned problems of the prior art.

Invention to solve the problems described above, to be tested was placed in a test chamber adjusted to freezing cold environment, the environmental testing method for icing humidified by the DUT to the test chamber, humidifying the test chamber a environmental test how to heat at least a portion of the inner wall of the case and / or prior to humidification test chamber to.
The invention according to claim 1 is an environment test method for humidifying a test chamber in a low-temperature environment below freezing to allow an object to be tested placed in the test chamber to icy, in which the test chamber is set to a low-temperature environment below freezing. An environment characterized by sequentially starting a cooling step of adjusting, an icing preparation step of heating at least a part of an inner wall of the test chamber to a temperature above a freezing point, and an icing step of humidifying the test chamber. It is a test method.

In the environmental test method of the present invention, the temperature of the inner wall of the test chamber can be raised when or before the humidification of the test chamber. Therefore, icing on the inner wall of the test chamber is suppressed, and more of the humidified air contributes to icing on the DUT.

An invention that solves the same problem is to use a structure including a test room and an environmental test device equipped with an air conditioner that exerts an air conditioning function, and install an object under test in a test room adjusted to a low temperature environment below freezing. In an environmental test method for humidifying a test chamber to frost on an object to be tested, at least one of a structure and an air conditioner to which humidified air comes into contact when and/or prior to humidifying the test chamber. Te is the environmental test how to heat at least a portion thereof.
The invention according to claim 2 uses an environmental test apparatus equipped with a structure including a test chamber and an inner wall, and a cooler exhibiting a cooling function, and humidifies the test chamber in a low temperature environment below freezing, In the environmental test method of icing the DUT to be installed in the test chamber, at least one of the cooling step of adjusting the test chamber to a low temperature environment below freezing, the inner wall and the cooler, at least the It is an environmental test method characterized by sequentially starting an icing preparation step of heating a part of the temperature above a freezing point and an icing step of humidifying the test chamber.

Also in the environmental testing method of the present invention, each part can be heated to raise the temperature when or before humidifying the test chamber. Therefore, useless icing on the test chamber is suppressed, and more of the humidified air contributes to icing on the DUT.

The invention according to claim 3 is characterized in that a depressurizing step of depressurizing the inside of the test chamber is executed, and after the depressurizing step, the icing preparation step is executed. Is the way.
There are air-conditioned space communicating with the test chamber, prior to the time and / or humidification to humidify the test chamber, not to desired to heat a portion or all of the conditioned space.

According to the present invention, it is possible to prevent icing in the air-conditioned space.

There is an air conditioning apparatus for adjusting a test room environment, prior to the time and / or humidification to humidify the test chamber, not to desired to heat or warmth a part or the whole of the air conditioner.
The invention according to claim 4, there is an air conditioning space communicating with said test chamber, in the icing preparation step, claim 1, wherein heating the part or the whole of the inner wall of the conditioned space The environmental test method described in any one of 1.

According to the present invention, it is possible to prevent icing on the air conditioner.

The test chamber has to desired to humidify while vacuum.
The invention according to claim 5 is the environmental test method according to any one of claims 1 to 4 , wherein in the icing preparation step, the test chamber is humidified in a depressurized state.
The invention according to claim 6 humidifies a test chamber adjusted to a low-temperature environment below freezing by using a cooling device, and causes an object to be tested installed in the test chamber to be iced. At the time of humidifying the chamber and/or prior to humidifying, at least a part of the inner wall of the test chamber is heated by a heater, and the test chamber is depressurized by depressurizing means so that the test object is allowed to ice. This is a characteristic environmental test method.

Another invention for solving the above-mentioned problems is an adiabatic tank including a test chamber in which an object to be tested is installed, a cooling device capable of lowering the temperature in the test chamber to a temperature below freezing, and In an environmental testing device that has a humidifying device for humidifying, installs the DUT in a test room adjusted to a low temperature environment below freezing, and then humidifies the test chamber to allow the DUT to ice. It is an environmental testing device having an inner wall heating means for heating at least a part of an inner wall of a tank.
The invention according to claim 7 is an adiabatic tank including a test chamber in which an object to be tested is installed, a cooling device capable of lowering the temperature in the test chamber to a temperature below freezing point, and a humidifying device for humidifying the test chamber. In the environmental testing apparatus capable of humidifying the test chamber in a low temperature environment below freezing and allowing the DUT to be installed in the test chamber to icy, the heat insulation tank is an inner casing, An inner wall that has an outer casing that covers the periphery of the inner casing, and a heat insulating material is interposed in a space between the inner casing and the outer casing, and that heats at least a part of the inner casing. It is an environmental testing device comprising a heating means, wherein the thickness of the inner casing is smaller than the thickness of the outer casing.
The invention according to claim 8 is an adiabatic tank including a test chamber in which an object to be tested is installed, a cooling device capable of lowering the temperature in the test chamber to a temperature below freezing point, and a humidifying device for humidifying the test chamber. In the environmental testing apparatus capable of humidifying the test chamber in a low temperature environment below freezing and allowing the DUT to be installed in the test chamber to icy, the heat insulation tank is an inner casing, An inner casing is provided with an outer casing that covers the periphery of the inner casing, and a heat insulating material is interposed in a space between the inner casing and the outer casing. The inner casing is made of a stainless steel plate. The outer casing is made of a steel plate, and has an inner wall heating means for heating at least a part of the inner casing.
The invention according to claim 9 is the environmental test apparatus according to claim 7 or 8, characterized in that the inner wall heating means is a heater and is installed on the outer surface side of the inner casing.
The invention according to claim 10 has a decompression means for decompressing the inside of the test chamber, and the space communicates with the test chamber, wherein the environmental test device according to any one of claims 7 to 9. Is.
The invention according to claim 11 is characterized in that the wall thickness of the outer casing is 5 times or more as compared with the wall thickness of the inner casing. It is a test device.
According to a twelfth aspect of the present invention, there is an air-conditioned space communicating with the test chamber, a cooler is built in the air-conditioned space, and it is possible to raise the temperature of part or all of the cooler. The environment testing device according to any one of claims 7 to 11, characterized in that.
According to a thirteenth aspect of the present invention, a heat insulating tank including a test chamber in which an object to be tested is installed, a cooling device capable of lowering the temperature in the test chamber to a temperature below freezing, and a humidifying device for humidifying the test chamber. In an environmental testing device capable of humidifying the test chamber in a low temperature environment below freezing and allowing the DUT to be installed in the test chamber to ice, the inside of the heat insulation tank is tested by a partition wall. It is an environmental testing device which is divided into a room and an air-conditioned space, and an inner wall heating means is provided on the partition wall.
According to a fourteenth aspect of the present invention, a heat insulating tank including a test chamber in which an object to be tested is installed, a cooling device capable of lowering the temperature in the test chamber to a temperature below freezing, and a humidifying device for humidifying the test chamber. In the environmental test device having a control device, the test chamber can be humidified in a low temperature environment below freezing, and the test object installed in the test chamber can be iced, wherein the control device is the A cooling step of adjusting the test chamber to a low temperature environment below freezing; an icing preparation step of heating at least a part of at least one of the inner wall of the test chamber and the cooling device to a temperature above freezing; and humidifying the test chamber. The environmental test apparatus is characterized by sequentially starting the icing step to be performed.
The invention according to claim 15 has an adiabatic tank including a test chamber in which an object to be tested is installed, a cooling device capable of lowering the temperature in the test chamber, and a humidifying device for humidifying the test chamber, In an environmental test apparatus capable of humidifying the test chamber in a low temperature environment below freezing and allowing the DUT to be installed in the test chamber to ice, a heater for heating at least a part of an inner wall of the test chamber. A pressure reducing means for reducing the pressure in the test chamber, wherein at least part of the inner wall of the test chamber is heated by the heater when the test chamber is humidified and/or prior to the humidification, It is an environmental test apparatus characterized in that the test object is iced in a state where the pressure in the test chamber is reduced.

In the environment testing apparatus of the present invention, the inner wall heating means can heat the inner wall of the heat insulation tank, so that icing on the inner wall is suppressed.

In the above-mentioned environmental testing device, the inner wall heating means is a heater, and has an inner casing that constitutes a part or all of the inner wall of the heat insulation tank, and an outer casing that covers the periphery of the inner casing. is interposed heat insulating material in the space between the outer housing have to desirable that the heater is provided on the outer surface side of the inner casing.

It has a decompression means for decompressing the inside of the test chamber, has an inner casing that constitutes part or all of the inner wall of the heat insulation tank, and an outer casing that covers the periphery of the inner casing. the space between communicates with the test chamber, the wall thickness of the outer housing, not to want to be more than five times as compared with the meat pressure of the inner casing.

In the environment test apparatus of the present invention, the space between the inner casing and the outer casing communicates with the test chamber. Therefore, even if the pressure inside the test chamber is reduced, the pressure difference between the inside and outside of the inner casing is small. Therefore, the force applied to the inner housing is small, and the rigidity of the inner housing is relatively low.
On the other hand, the pressure difference between the inside and outside of the outer casing becomes large when the pressure inside the test chamber is reduced, and the force due to atmospheric pressure is applied to the outer casing.
In the environmental testing device of the present invention, the outer casing has a large wall thickness so as to withstand the force caused by the atmospheric pressure.
On the other hand, in the environment testing device of the present invention, the thickness of the inner casing is thin. Therefore, the inner casing used in the present invention has a relatively small heat capacity and the temperature easily rises, so that it is difficult for the surface to be iced.

There is an inner casing that forms part or all of the inner wall of the heat insulation tank, and an outer casing that covers the periphery of the inner casing. Inside the inner casing, there is an air-conditioned space that communicates with the test chamber. and air-conditioning equipment is built within, it has to desired part of the conditioned space and / or air conditioning device or may be heated or kept warm all.

According to the present invention, it is possible to prevent icing from landing in an air-conditioned space or air-conditioning equipment.

INDUSTRIAL APPLICABILITY The environmental test method and the environmental test device of the present invention have an effect of suppressing unnecessary ice accretion when carrying out an ice accretion test.

It is sectional drawing which shows notionally the structure of the environment testing apparatus of embodiment of this invention. It is a cross-sectional perspective view which shows the outline of a structure of the heat insulation tank of the environmental testing apparatus of FIG. It is an expanded sectional view of the heat insulation wall of the heat insulation tank of the environmental testing apparatus of FIG. It is sectional drawing of the environmental testing apparatus of FIG. 1, and shows a cooling process. It is sectional drawing of the environmental testing apparatus of FIG. 1, and shows a pressure reduction process. It is sectional drawing of the environmental testing apparatus of FIG. 1, and shows an icing preparation process (heating process). It is sectional drawing of the environmental testing apparatus of FIG. 1, and shows an icing process. It is sectional drawing of the environmental testing apparatus of FIG. 1, and shows a melting process. 3 is a flowchart showing the operation of the environment test apparatus of FIG. 1. It is sectional drawing which shows notionally the structure of the environmental testing apparatus of other embodiment of this invention.

Hereinafter, embodiments of the present invention will be described.
First, the basic structure of the environment test apparatus 1 of this embodiment will be described. The environment test apparatus 1 of the present embodiment includes a heat insulating tank 3 that is a structure and an air conditioner 10 that exhibits an air conditioning function.
That is, the environment testing device 1 of the present embodiment has a heat insulating tank 3 covered with a heat insulating wall 2 as shown in FIG. The heat insulating tank 3 has a door for putting in and taking out the DUT, but the door is well known, and the description and illustration thereof are omitted.
A partition wall 7 is provided inside the heat insulating tank 3, and the partition wall 7 divides the heat insulating tank 3 into a test chamber 5 and an air-conditioned space 15.
The test chamber 5 is a space in which the DUT is installed. The test chamber 5 is a space in which six surfaces are surrounded by the inner wall of the heat insulation tank 3 and the partition wall 7.

An air conditioning device 10 and a blower 11 are built in the air-conditioned space 15 of the environment test apparatus 1. The air conditioner 10 includes a cooler 6, a heating device 17, and a humidifying device 8.
The cooler 6 is an evaporator of the cooling device 20, and the refrigerant that changes the phase flows therein.
The cooling device 20 includes a compressor 21, a condenser 22, an expansion means 23, and a cooler (evaporator) 6 connected in an annular shape, and compresses, condenses, expands and evaporates the refrigerant, and cools the cooler. The surface temperature of the (evaporator) 6 can be lowered. Hereinafter, this operation is referred to as a normal cooling operation.
Further, the cooling device 20 includes a hot gas introduction circuit (not shown), and introduces the high temperature refrigerant gas compressed by the compressor 21 into the cooler 6 to remove the frost adhering to the surface of the cooler 6. You can drive.

Further, the cooling device 20 has a function of performing a frost-free operation.
That is, in the cooling device 20 used in the present embodiment, the downstream side of the cooler (evaporator) 6 is branched, and is divided into the throttle side flow passage 30 and the open flow passage 31.
Downstream throttle means 32 is provided in the throttle passage 30.
The open flow path 31 is a flow path that bypasses the downstream throttle means 32, and an opening/closing valve 33 is provided.

In the frost-free operation, the on-off valve 33 is closed, and the refrigerant passes from the cooler (evaporator) 6 through the throttle side flow path 30 and returns to the compressor 21. As a result, the evaporation pressure of the refrigerant in the cooler (evaporator) 6 is controlled to be constant by the downstream throttle means 32.
Here, the temperature of the refrigerant is uniquely determined by the evaporation pressure of the refrigerant. Therefore, when the refrigerant in the cooler (evaporator) 6 is in a gas-liquid mixed state (wet vapor), the temperature of the refrigerant is uniquely determined by the evaporation pressure of the refrigerant. Therefore, the surface temperature of the cooler (evaporator) 6 becomes constant.
In the present embodiment, in the frost-free operation, the opening degree of the downstream throttle means 32 is adjusted so that the surface temperature of the cooler (evaporator) 6 slightly exceeds the freezing point temperature. That is, the opening degree of the downstream throttle means 32 is adjusted so that the surface of the cooler (evaporator) 6 does not freeze and the temperature becomes relatively low (about 0.2 to 3 degrees Celsius). ..

When the normal cooling operation is performed, the on-off valve 33 is opened, and the surface temperature of the cooler (evaporator) 6 drops to a temperature much lower than the freezing point temperature as in the case of a normal cooling device.

The heating device 17 is a known electric heater.
The humidification device 8 is a kind of boiler and emits steam. The air-conditioned space 15 has only a steam outlet 35 for discharging steam, and the main body portion 36 of the humidifier 8 is outside the heat insulating tank 3.
Further, in this embodiment, since it is necessary to depressurize the test chamber 5, a steam supply valve 37 is provided between the main body portion 36 and the steam outlet 35. The steam supply valve 37 is an open/close valve such as a known solenoid valve.

The air-conditioned space 15 constitutes an air-conditioning air passage communicating with the test chamber 5 in an annular shape, and contains the air-conditioning equipment 10 and the blower 11.

The air-conditioned space 15 is formed in a part of the heat insulating tank 3, and communicates with the test chamber 5 at two locations, an air blowing section 16 and an air introducing section 18.
Therefore, when the blower 11 is started, the air in the test chamber 5 is introduced into the air-conditioned space 15 from the air introduction part 18. Then, the air-conditioned space 15 is ventilated, and the air is brought into contact with the air-conditioning equipment 10 to perform heat exchange and humidity adjustment, and the adjusted air is blown out from the air blowing portion 16 into the test chamber 5.
A temperature sensor 12 and a humidity sensor 13 are provided near the air blowing section 16 in the air-conditioned space 15.
When using the environment test apparatus 1, the air blower 11 is operated to make the inside of the air-conditioned space 15 a ventilation state, and the detected values of the temperature sensor 12 and the humidity sensor 13 approach the temperature and humidity of the set environment. Control 10
As a result, a desired environment is created in the test room 5.

Next, the structure of the heat insulation tank 3 which is the structure of the environment test apparatus 1 of the present embodiment will be described.
As shown in FIGS. 2 and 3, the heat insulating tank 3 has a double structure in which an inner casing 40 and an outer casing 41 are arranged in a nested manner. A heat insulating material filling space 45 between the two is filled with a heat insulating material 42 such as a foam material or glass wool.
Note that FIG. 2 is a cross-sectional perspective view of the inner housing 40 and the outer housing 41, and illustration of portions corresponding to front walls of the inner housing 40 and the outer housing 41 is omitted.
The inner casing 40 constitutes the inner wall 50 of the heat insulating tank 3, and is made of a thin metal plate having a thickness of about 0.8 mm to 2.0 mm. Specifically, the inner housing 40 is made of a stainless steel plate.

On the other hand, the outer casing 41 is made of a considerably thick structural steel plate. The thickness of the outer casing 41 is 5 times or more the thickness of the inner casing 40, and more preferably 8 times or more.
The inner volume of the outer casing 41 is larger than the outer volume of the inner casing 40, the outer casing 41 covers the entire circumference of the inner casing 40, and the heat insulating material filling space 45 is provided between the both. In the present embodiment, there is a communication hole (not shown) in a part of the inner casing 40, and the inside of the inner casing 40 and the heat insulating material filling space 45 communicate with each other and have air permeability.

In the present embodiment, as shown in each drawing, the inner wall heating means 60 is provided on the outer surface of the inner casing 40. The inner wall heating means 60 is a thin linear electric heater, and is arranged on the outer surface of the inner casing 40 so as to be widely distributed. The inner wall heating means 60 is pressed against the outer surface of the inner housing 40 by a screw or the like (not shown).
In the present embodiment, the inner casing 40 has six surfaces, namely, a front wall 61, a back wall 62, a top wall 63, a bottom wall 65, and left and right side walls 67, 68, but on the outer surfaces of all the walls, Inner wall heating means 60 is attached.

A door (not shown) is provided on any surface of the heat insulating tank 3 as described above. In the present embodiment, the door portion also has a double structure like the other portions, and the inner wall heating means 60 is provided on the outer surface of the member corresponding to the inner casing 40.

An inner wall temperature sensor 70 that detects the temperature of the inner wall of the inner casing 40 is provided on the inner wall of the inner casing 40.
Further, the inner wall heating means 60 is attached to the air-conditioned space 15 side of the partition wall 7 described above.

In this embodiment, as described above, the partition wall 7 is provided inside the heat insulating tank 3, and the partition wall 7 divides the inside of the heat insulating tank 3 into the test chamber 5 and the air-conditioned space 15.
In other words, the test chamber 5 is a space surrounded by the front wall 61, the top wall 63, the bottom wall 65, the left and right side walls 67 and 68, and the partition wall 7 of the heat insulating tank 3. In addition, since the front wall 61 of the heat insulation tank 3 generally has a door (not shown), the test chamber 5 includes the front wall 61 including the door, the top wall 63, the bottom wall 65, the left and right side walls 67, 68, and more precisely. It is a space surrounded by a partition wall 7.
In the present embodiment, as described above, the inner wall heating is performed on the front wall (including the door if there is a door) 61, the top wall 63, the bottom wall 65, the left and right side walls 67, 68 and the partition wall 7 of the heat insulating tank 3. Since the means 60 is attached, it is possible to raise the temperature of all the inner walls constituting the test chamber 5 by the inner wall heating means 60.

Similarly, the air-conditioned space 15 is a space surrounded by the partition wall 7 and the back wall 62 (to be exact, includes a part of another wall).
In the present embodiment, as described above, since the inner wall heating means 60 is attached to the partition wall 7 and the inner wall 62, the temperature of all the inner walls constituting the air-conditioned space 15 should be raised by the inner wall heating means 60. You can

Further, in the environment test apparatus 1 of this embodiment, the vacuum pump 71 is connected to the test chamber 5 via the opening/closing valve 86 by piping. The open/close valve 86 is a known solenoid valve or the like.
Further, an atmosphere opening valve 72 is connected to the test chamber 5 by piping. A pressure sensor 73 is provided in the test chamber 5.
Inside the test chamber 5, there is a water receiving slope 75, and the lowermost part of the water receiving slope 75 communicates with the outside via a drain valve 76.

Next, the function of the environment test apparatus 1 of the present embodiment will be described according to the procedure of the icing test.
The icing test is performed by repeating the following steps multiple times.
In this embodiment, the following steps are sequentially performed. In the environment test apparatus 1 of the present embodiment, a control device (not shown) stores a program that sequentially executes the following steps, and the steps are automatically repeated a predetermined number of times.
(1) Cooling process Set the test room in a low temperature environment and expose the DUT to it.
(2) Pressure reduction process The pressure inside the test chamber is reduced.
(3) Ice accretion preparation step (heating step)
The water vapor passage including the inner wall of the test chamber 5 is heated.
(4) Ice accretion process (humidification process)
Humidify the inside of the test chamber and allow water vapor to condense and freeze on the surface of the DUT.
(5) Melting step The inside of the test chamber is heated to melt the ice adhering to the DUT.

The icing test is performed by setting the DUT 80 in the test chamber 5 as shown in FIG. Here, a temperature sensor (referred to as an object temperature sensor) 81 is attached to the DUT 80.
Hereinafter, description will be given with reference to the flowchart of FIG. 9 and FIGS. 4 to 8.
In the icing test, the cooling process is started as the first process (step 1).
In the cooling step, the cooling device 20 is normally cooled and the blower 11 is started, and the air in the test chamber 5 is introduced into the air-conditioned space 15 from the air introduction part 18 to be cooled and returned to the test chamber 5. The temperature inside the test chamber 5 is lowered (FIG. 4).
That is, the surface temperature of the cooler (evaporator) 6 is lowered to below freezing, and in step 2, the temperature inside the test chamber 5 is waited until it falls to a set temperature (for example, 20 degrees below freezing (Celsius)).

In the present embodiment, the temperature of the DUT 80 is also monitored by the object temperature sensor 81, and in Step 3, the temperature of the DUT 80 waits for the temperature to drop to, for example, 20 degrees below freezing (Celsius).
When it is confirmed in step 3 that the temperature of the DUT 80 has dropped to the set temperature, the subsequent steps 4 and 5 wait for the temperature of the DUT 80 to stabilize.
That is, when it is confirmed that the temperature of the DUT 80 has dropped to the set temperature, the time measurement is started in step 4, and when the predetermined time has elapsed in step 5, it is considered that the temperature of the DUT 80 is stable. The process proceeds to step 6 and the cooling process ends.

Then, the depressurization process of step 7 is performed. The cooling step may be continued during the depressurization step.
In the depressurizing step, as shown in FIG. 5, the opening/closing valve 86 is opened and the vacuum pump 71 is started to depressurize the inside of the test chamber 5. In the depressurizing step, the atmosphere release valve 72, the drain valve 76, and the steam supply valve 37 are closed because it is necessary to seal the inside of the heat insulating tank 3.
The blower 11 is driven at a very low speed.

Then, the pressure sensor 73 continues to reduce the pressure until the pressure in the test chamber 5 reaches a pressure corresponding to a predetermined altitude above the sky.
In the present embodiment, the inner casing 40 has a small thickness and low rigidity, but the inside casing 40 and the heat insulating material filling space 45 are in communication with each other and are breathable, and The atmospheric pressure is almost the same, and the atmospheric pressure is not directly applied to the inner casing 40, so that the deformation of the inner casing 40 is suppressed.
In this embodiment, the atmospheric pressure mainly acts on the outer housing 41. The outer casing 41 has high rigidity and is unlikely to be deformed even under atmospheric pressure.

When it is confirmed in step 8 that the pressure in the test chamber 5 has dropped to a predetermined pressure, the process proceeds to step 9 and the icing preparation process (heating process) is started. In the icing preparation step, as shown in FIG. 6, the inner wall heating means 60 is driven to raise the temperature of each part, and the frost-free operation of the cooling device 20 is performed.

As a result, in the humidification step, the temperature of the part that the steam contacts is raised to a temperature above the freezing point temperature.
Specifically, the inner wall 50 of the test chamber 5 and the inner wall of the air-conditioned space 15 are heated to a temperature exceeding the freezing point temperature. In addition, it is not desirable that the temperature of the inner wall 50 of the test chamber 5 becomes excessively high, and the temperature is raised slightly above the freezing point temperature as the target temperature. Functionally, the temperature is such that freezing does not easily occur on the inner wall 50 of the test chamber 5 or the like, and specifically, it is about 0.2 to 2 degrees Celsius.
By the icing preparation step (heating step), a portion of the structure including the test chamber 5 through which water vapor passes is heated to raise the temperature. Further, in the air conditioner 10, the surface temperature of the cooler 6 is raised to a temperature exceeding the freezing point temperature and kept warm.

In this embodiment, examples of the structure that constitutes the test chamber 5 include the front wall 61, the top wall 63, the bottom wall 65, the left and right side walls 67 and 68, and the partition wall 7 of the heat insulating tank 3. In the present embodiment, as described above, the inner wall heating means 60 is attached to the front wall 61, the top wall 63, the bottom wall 65, the left and right side walls 67 and 68, and the partition wall 7 of the heat insulation tank 3, and the test chamber 5 is installed. The constituent structure is heated to raise the temperature.
Further, in the present embodiment, the partition wall 7 and the back wall 62 (to be exact, a part of another wall is included) can be cited as the structures constituting the air-conditioned space 15. In the present embodiment, as described above, the inner wall heating means 60 is attached to the partition wall 7 and the back wall 62, and the structure constituting the air-conditioned space 15 is heated to raise the temperature.

The temperature of the inner wall of the heat insulation tank 3 is monitored by the inner wall temperature sensor 70, and the inner wall heating means 60 is energized until the temperature detected by the inner wall temperature sensor 70 slightly exceeds 0 degrees Celsius.
In addition, since the cooling device 20 is operated without frost, the surface temperature of the cooler 6 is maintained at a temperature exceeding 0 degree.

When it is confirmed in step 10 that the temperature of each part is completed, the process proceeds to step 11, and the humidification process is started. In the humidifying step, as shown in FIG. 7, the main body part 36 of the humidifying device 8 is driven, the steam supply valve 37 is opened, and steam (actually humidified air) is supplied from the steam outlet 35 into the heat insulating tank 3. .. Actually, in order to reduce the time, it is confirmed in step 10 that the driving of the main body portion 36 of the humidifying device 8 is started and preheated at an earlier time, and the temperature rise of each portion is completed. Then, the steam supply valve 37 is opened, and steam is supplied from the steam outlet 35 into the heat insulating tank 3.
In the humidification step, the blower 11 is rotated at a slight speed, and the steam exits the air-conditioned space 15 and is introduced into the test chamber 5.
The humidifier 8 is operated so that the relative humidity in the test chamber 5 becomes a high humidity environment of about 95%. Then, the water vapor comes into contact with the low temperature test object 80, and the test object 80 freezes.

On the other hand, the water vapor also comes into contact with the inner wall 50 of the test chamber 5 and the inner wall of the air-conditioned space 15, but since these portions are preheated to a temperature above the freezing point by the inner wall heating means 60, no ice is generated. ..
Therefore, most of the steam supplied from the humidifier 8 contributes to icing on the DUT 80.

The temperature of the inner wall 50 of the test chamber 5 is higher than that of the DUT 80, but the test chamber 5 is decompressed, and the air that is a medium for transmitting heat to the DUT 80 is diluted. The heat of the inner wall 50 is difficult to transfer to the DUT 80. Therefore, the DUT 80 maintains a low temperature, and much icing occurs.

In the icing step (humidifying step), the steam on the surface of the DUT 80 undergoes a phase change to become ice, so that the latent heat of the steam gradually raises the temperature of the DUT 80. The surface temperature of the DUT 80 is monitored by the object temperature sensor 81, and when the temperature reaches a predetermined end temperature above the freezing point temperature, the process proceeds from step 12 to step 13 to end the humidification process. .. That is, as shown in FIG. 8, the driving of the main body portion 36 of the humidifier 8 is stopped, the steam supply valve 37 is closed, and the supply of steam from the steam outlet 35 into the heat insulating tank 3 is stopped.

In the following step 14, the atmosphere opening valve 72 is opened to return the inside of the test chamber 5 to atmospheric pressure. Further, in step 15, the heating device 17 is driven to raise the temperature inside the test chamber 5 and the ice adhered to the DUT 80 is thawed.
Water generated by melting the ice flows through the water receiving slope 75, the drain valve 76 is opened, and the water is discharged to the outside.

When the drainage is completed, 1 is added to the numerical value n of the counter of the control device (not shown). If the numerical value n of the counter has not reached the predetermined number of repetitions N, step 18 becomes NO, the process returns to step 1 and the same process is repeated again.
When the test has been performed a predetermined number of times, the icing test ends.

In the embodiment described above, in the humidification step, the steam was supplied entirely into the test chamber 5. However, as in the environmental test apparatus 85 shown in FIG. 10, the piping network 83 is provided around the DUT 80. The steam may be blown onto the DUT 80 from the piping network 83, or only the circumference of the DUT 80 may be in a steam atmosphere.

In the embodiment described above, the inner wall 50 or the like of the test chamber 5 is heated prior to the humidifying step, but the inner wall 50 or the like may be heated in parallel with the humidifying step.

In the environment testing apparatus 1 described above, the heat insulation tank 3 has a double structure, and the wall pressure forming the inner side is thin.
With this configuration, the heat capacity of the inner wall 50 can be reduced, and the temperature of the inner wall 50 can be raised in a short time. However, the present invention is not limited to this configuration, and the inner wall 50 may have a large thickness.

In the environment testing device 1 described above, the frost-free operation of the cooling device 20 was performed prior to the humidification process. Whether or not the frost-free operation of the cooling device 20 is performed during the humidification step is arbitrary, and the frost-free operation is continued during the humidification step so that the surface temperature of the cooler (evaporator) 6 exceeds the freezing point temperature. You may keep it at temperature. Moreover, you may stop operation|movement of the cooling device 20 at the time of a humidification process.
In the icing preparation step (heating step), the surface temperature of the cooler (evaporator) 6 may be increased by defrosting operation instead of operating the cooling device 20 without frost.
A small heater may be attached to the cooler 6 to raise the surface temperature of the cooler (evaporator) 6.

In the environment testing device 1 described above, the inner wall heating means 60 is a linear electric heater, but may be an electric heater of another form. For example, a block-shaped or planar electric heater may be used. Further, the inner wall heating means is not limited to the electric heater, and may be a heat pump applied or hot air used.

The environment testing device 1 described above is mainly intended for testing aircraft parts and has a function of humidifying under reduced pressure. However, the present invention can also be applied to the case where a component other than an aircraft is used as the DUT.
For example, the invention can be applied to a vehicle such as an automobile and an icing test for electronic devices such as a mobile terminal. When the present invention is applied to an ice accretion test of a vehicle or an electronic device, humidification may be performed without a depressurizing step.

In the environment testing device 1 described above, the inner wall heating means 60 is provided on the entire surfaces of the heat insulating tank 3 and the partition wall 7, but it may be provided only on a part thereof.
In the environment testing device described above, the inner wall heating means 60 is provided on the outer surface of the inner housing 40, but it may be attached to the inner surface of the inner housing 40, or may be embedded in the inner housing 40 or the partition wall 7. May be.

1, 85 Environmental test device 3 Insulation tank 5 Test chamber 6 Cooler 7 Partition wall 8 Humidifier 11 Blower 15 Air-conditioned space 20 Cooling device 40 Inner casing 41 Outer casing 50 Inner wall 60 Inner wall heating means 71 Vacuum pump 80 DUT

Claims (15)

Humidification in a low temperature environment below freezing in the test chamber, in the environmental test method for icing on the DUT installed in the test chamber ,
A cooling step of adjusting the test chamber to a low temperature environment below freezing,
And icing preparation step of heating at least a portion of the inner wall of the test chamber to a temperature above the freezing point,
An icing step of humidifying the test chamber,
Environmental test method characterized by starting sequentially . Using a structure including a test chamber and an inner wall , and an environmental test device equipped with a cooler that exerts a cooling function , humidify the test chamber in a low-temperature environment below freezing, and install the test target in the test chamber. In the environmental test method of icing on objects,
A cooling step of adjusting the test chamber to a low temperature environment below freezing,
At least one of the inner wall and the cooler , an icing preparation step of heating at least a portion thereof to a temperature above a freezing point ,
An icing step of humidifying the test chamber,
Environmental test method characterized by starting sequentially . A depressurizing step of depressurizing the test chamber is executed,
The environmental test method according to claim 1 or 2, wherein the icing preparation step is performed after the depressurization step. There is an air conditioning space communicating with said test chamber,
The said icing preparation process WHEREIN: A part or all of the inner wall of the said air-conditioned space is heated, The environmental test method in any one of Claim 1 thru|or 3 characterized by the above-mentioned. The environmental test method according to claim 1 , wherein, in the icing preparation step, the test chamber is humidified in a depressurized state. Humidifying the test chamber adjusted to a low temperature environment below freezing using a cooling device, in an environmental test method for icing the DUT to be installed in the test chamber,
At the time of humidifying the test chamber and/or prior to the humidification, at least a part of the inner wall of the test chamber is heated by a heater, and the test chamber is depressurized by depressurizing means to allow the object to be iced. Environmental test method characterized by the following. A thermal insulation vessel containing the test chamber for installing the DUT has a cooling device capable of lowering the temperature of the test chamber below freezing temperature, a humidifier for humidifying the test chamber, subzero said test chamber In an environment test device capable of icing on a DUT installed in the test chamber by humidifying in a low temperature environment of
The heat insulating tank has an inner housing and an outer housing that covers the periphery of the inner housing, and a heat insulating material is interposed in a space between the inner housing and the outer housing.
An inner wall heating means for heating at least a part of the inner casing,
An environmental test apparatus , wherein the thickness of the inner casing is smaller than the thickness of the outer casing . A heat insulation tank including a test chamber in which a device under test is installed, a cooling device capable of lowering the temperature in the test chamber to a temperature below freezing point, and a humidifying device for humidifying the test chamber, and the test chamber is below freezing point. In an environment test device capable of icing on a DUT installed in the test chamber by humidifying in a low temperature environment of
The heat insulating tank has an inner housing and an outer housing that covers the periphery of the inner housing, and a heat insulating material is interposed in a space between the inner housing and the outer housing.
The inner housing is made of a stainless steel plate, the outer housing is made of steel plate,
An environmental test device comprising an inner wall heating means for heating at least a part of the inner casing. The inner wall heating means is a heater, the environment test apparatus according to claim 7 or 8, characterized in that it is installed on the outer surface of the inner housing. Has a decompression means for decompressing the said test chamber, the space environment testing apparatus according to any one of claims 7 to 9, wherein the communication to Rukoto and the test chamber. 11. The environmental test device according to claim 7, wherein the thickness of the outer casing is 5 times or more the thickness of the inner casing. There are air-conditioned space that communicates with the test chamber, which cooler is incorporated in the conditioned space,
Environmental testing apparatus according to any one of claims 7 to 11, characterized in that it is possible to raise the temperature of the part or the whole of the cooler. A heat insulation tank including a test chamber in which a device under test is installed, a cooling device capable of lowering the temperature in the test chamber to a temperature below freezing point, and a humidifying device for humidifying the test chamber, and the test chamber is below freezing point. In an environment testing device capable of humidifying in a low temperature environment, and allowing the DUT to be installed in the test chamber to ice.
An environmental test apparatus characterized in that the inside of the heat insulation tank is partitioned by a partition wall into the test chamber and the air-conditioned space, and the partition wall is provided with an inner wall heating means. An adiabatic tank including a test chamber in which the DUT is installed, a cooling device capable of lowering the temperature in the test chamber to a temperature below freezing point, a humidifying device for humidifying the test chamber, and a control device, In an environmental test device capable of humidifying a test chamber in a low temperature environment below freezing, and allowing an object to be tested placed in the test chamber to ice.
The control device is
A cooling step of adjusting the test chamber to a low temperature environment below freezing,
At least one of the inner wall of the test chamber or the cooling device, an icing preparation step of heating at least a portion thereof to a temperature above the freezing point,
An icing step of humidifying the test chamber,
Environmental test equipment characterized by sequentially starting. An insulating tank including a test chamber in which a device under test is installed, a cooling device capable of lowering the temperature in the test chamber, and a humidifying device for humidifying the test chamber, and the test chamber is under a low temperature environment below freezing. In an environmental test device capable of icing on a DUT installed in the test chamber,
A heater for heating at least a part of the inner wall of the test chamber,
Decompression means for decompressing the test chamber,
Have
When the test chamber is humidified and/or prior to the humidification, at least a part of the inner wall of the test chamber is heated by the heater, and the test chamber is depressurized by the depressurizing means, and then attached to the DUT. Environmental test device characterized by making it ice.

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