JP6670205B2 - Low-temperature air supply device and environmental test device - Google Patents

Description

  The present invention relates to a low-temperature air supply device that supplies a large amount of low-temperature air. The low-temperature air supply device of the present invention is suitable for use in performing an environmental test. The present invention also relates to an environmental test device provided with a low-temperature air supply device.

One of the test methods for examining the performance of a device under test such as a mechanical device or an electronic device is an environmental test.
The environmental test reproduces an environment in which the DUT is actually placed or a more severe environment, and examines the state of the DUT.
For example, if the DUT is used in a high-latitude region or a polar region, a low-temperature environment is artificially created by an environmental test apparatus, and the DUT is exposed to the environment to perform a desired test.

There are devices that consume air, such as combustion devices and engines. When conducting an environmental test on such equipment that consumes air, simply placing the test object in a high or low temperature test room is not enough to perform the test.Continuously supplying fresh air to the test object is not sufficient. There must be.
For example, in order to examine the performance of a burner in a cryogenic environment, it is necessary to constantly supply cold air to the burner.
The same is true for engines, in which cold cooled air must be supplied to the cylinders.

As one of devices capable of supplying low-temperature air, there is an air conditioner disclosed in Patent Document 1.
The air conditioner disclosed in Patent Literature 1 has a cooler disposed in an air conditioning flow passage, and cools air passing through the air conditioning flow passage by the cooler.
The air conditioner disclosed in Patent Literature 1 is suitable for circulating air with a test room.

JP 2007-162973

There is a demand in the market for testing the performance of burners and engines in an extremely cold environment such as minus 30 degrees Celsius.
The air conditioner disclosed in Patent Document 1 can supply low-temperature air, but it is difficult to continuously supply extremely low-temperature air such as minus 30 degrees Celsius to the DUT. was there.
Therefore, the applicants have prototyped a low-temperature air supply device 100 as shown in FIG.
The low-temperature air supply device 100 cools the passing air with brine.
The low-temperature air supply device 100 includes a main body device 101, a pre-dehumidification device 103, and a main dehumidification device 105.

The main device 101 has a ventilation path 107 and a brine supply device 102. The ventilation path 107 is surrounded by a cooling jacket 106.
The brine supply device 102 includes a brine tank 110 and a refrigerator 112, and can cool the brine in the brine tank 110 to a low temperature of about minus 40 degrees Celsius.
The brine supplied from the brine supply device 102 circulates through the cooling jacket 106 of the main device 101 described above.

The pre-dehumidifying device 103 is a water-cooled cooling passage, which dehumidifies air lightly.
On the other hand, the dehumidifying device 105 thoroughly dehumidifies air.
As the dehumidifier 105, a desiccant type dehumidifier is used. Here, the desiccant type dehumidifier uses a dehumidifying agent such as silica gel to adsorb water vapor in the air. Since the desiccant type dehumidifier adsorbs water vapor in the air by the dehumidifier, it can generate low-humidity air that can be said to be dry air.
The dehumidifier adsorbing water vapor can be regenerated by heating.
The inventor does not know any device other than the desiccant type dehumidifier as a dehumidifier that can withstand the requirement of the low-temperature air supply device 100.

In the low-temperature air supply device 100, a pre-dehumidification device 103, a main dehumidification device 105, and a main device 101 are connected in series in this order. Then, these are ventilated by the blower 116.
The air sent to the low-temperature air supply device 100 by the blower 116 is dehumidified by the pre-dehumidification device 103 and further thoroughly dehumidified by the dehumidification device 105.

  The air that has been substantially completely dehumidified is introduced into the main unit 101, and exchanges heat with the brine while passing through the ventilation passage 107 to be cooled. Then, the cooled air is discharged from the main body device 101 and provided for a desired use.

  According to the low-temperature air supply device 100, a desired low-temperature air can be continuously supplied in a large amount. The low-temperature air supply device 100 satisfies the required quality in the market.

However, the low-temperature air supply device 100 has a dissatisfaction that power consumption is excessive.
In the low-temperature air supply device 100, the power consumption of the main device 101 is large. In the low-temperature air supply device 100, the power consumption of the dehumidifier 105 is also large.

This will be described below.
In the prototype low-temperature air supply device 100, the brine is cooled to an extremely low temperature of about minus 40 degrees by the brine supply device 102.
Here, the efficiency of the refrigerator generally decreases as the target temperature decreases. As a measure of the efficiency of a refrigerator, a coefficient of performance (COP Coefficient of Performance) is known. For example, when an extremely low temperature of about minus 40 degrees is made, the coefficient of performance is about 1.0, which is quite bad.

  Further, when frost is formed on the ventilation path 107 of the main device 101, the ability to cool air is extremely reduced. Therefore, in the low-temperature air supply device 100, the air introduced into the main device 101 is thoroughly dehumidified to prevent frost in the ventilation passage 107.

Here, the desiccant type dehumidifier makes the dehumidifier adsorb the water vapor in the air, and therefore does not require energy when dehumidifying the air. However, the desiccant type dehumidifier needs to regenerate the dehumidifier by heating, and regenerating the dehumidifier requires large energy.
Therefore, the desiccant type dehumidifier consumes much electric power as a whole.

  The present invention focuses on the above-described problems, and aims to develop a low-temperature air supply device that can continuously supply low-temperature air to equipment that consumes air and that consumes relatively little power. Is what you do. It is another object of the present invention to develop an environmental test apparatus that tests equipment that consumes air and that consumes relatively little power.

The invention according to claim 1 for solving the above-mentioned problem has a series of ventilation paths from an air introduction section to an air discharge section, and a plurality of coolers capable of cooling air, and the plurality of coolers. Can reduce the temperature of itself and exchange heat with the air passing through the ventilation path, thereby reducing the temperature of the air passing through the ventilation path, and from the air introduction section toward the air discharge section. A cooler having a lower temperature is disposed, and at least two or more of the plurality of coolers are simultaneously driven .
That is, the invention according to claim 1 is a low-temperature air supply device that unilaterally supplies air to a supply target, wherein a series of ventilation paths from an air introduction section to an air discharge section, and air passing through the ventilation paths. A plurality of coolers capable of cooling the heat exchanger, the plurality of coolers exchange heat with the air passing through the ventilation path by lowering their own temperatures, and reduce the temperature of the air passing through the ventilation path. A cooler whose temperature is lower from the air inlet to the air outlet is arranged, and at least two or more of the plurality of coolers are simultaneously driven. Thus, it is possible to change the number of coolers to be operated according to the required temperature of the air, and the change in the number of coolers to be operated depends on the plurality of Excessive cooling capacity of cooler When a cold air supply device, characterized in that it is carried out by resting the downstream cooler of the plurality of coolers.
Another invention for solving the same problem is a low-temperature air supply device that unilaterally supplies air to a supply target, wherein a series of ventilation paths from an air introduction section to an air discharge section, and the ventilation path A plurality of coolers capable of cooling the air passing therethrough, the plurality of coolers reduce their temperature and exchange heat with the air passing through the ventilation path, and the temperature of the air passing through the ventilation path A cooler having a lower temperature is arranged from the air inlet to the air outlet, and at least two or more of the plurality of coolers are simultaneously driven. Wherein the plurality of coolers include those capable of changing a cooling capacity, wherein the cooling capacity can be changed according to conditions, and the change of the cooling capacity is operated. Downstream of multiple coolers A cold air supply system characterized in that it is carried out by changing the cooling capacity of the cooler.
It is preferable that three or more coolers are provided for one ventilation path.

The low-temperature air supply device of the present invention has a series of ventilation paths from the air introduction section to the air discharge section, and cools the air by passing the air through the ventilation paths.
Here, the low-temperature air supply device of the present invention has a plurality of coolers. The cooler lowers its own temperature to lower the temperature of the object, such as an evaporator of a refrigerator or a Peltier element.

In the low-temperature air supply device of the present invention, a plurality of coolers are provided, and a cooler having a lower temperature as it goes downstream is provided.
Therefore, a cooler (hereinafter, referred to as an upstream cooler) arranged at a position close to the air inlet has a relatively high temperature and a high coefficient of performance. Of course, even in the case of the upstream-side cooler, the temperature of the air itself is lower than that of the air passing through the portion.

  The air cooled by the upstream cooler flows toward the air discharge. Then, it comes into contact with the next installed cooler (hereinafter, referred to as a middle cooler). The air flowing through the middle part of the ventilation passage has a lower temperature than the air initially introduced, but the middle-side cooler has a lower temperature than the upstream-side cooler, so it deprives the passing air of heat and removes air. Can be further reduced.

The midstream cooler also has a high coefficient of performance because its own temperature is often higher than the ultimate target temperature.
The air cooled by the midstream cooler flows further toward the air discharge. Then, it comes into contact with a cooler (hereinafter, referred to as a downstream cooler) installed next. The air flowing downstream of the ventilation passage has a lower temperature than the air flowing through the midstream, but the downstream cooler has a lower temperature than the midstream cooler, so it deprives the passing air of heat and removes air. Can be further reduced.

The downstream cooler has a low coefficient of performance because its temperature is lower than the ultimate target temperature. However, in the low-temperature air supply device of the present invention, since the coefficient of performance of the coolers arranged in other basins is high, the overall efficiency is high and the power consumption is low.
Further, since the temperature of the air passing through the ventilation passage and the temperature of the coolers provided in the respective parts are relatively close, frost is not locally formed. Therefore, the dehumidification performed before passing through the ventilation path does not need to be thorough.
In the above description, the ventilation passage is divided into three regions: the upstream side, the middle flow side, and the downstream side. However, the present invention is not limited to this. Or may be divided into more.

The invention according to claim 6 has a plurality of ventilation systems having the series of ventilation paths and a plurality of coolers, and drives at least one ventilation system to lower the temperature of air passing through the ventilation paths. The low-temperature air supply device according to any one of claims 1 to 5, wherein the defrosting of the cooler of at least one other ventilation system can be performed during the operation.

  According to the low-temperature air supply device of the present invention, it is possible to continuously supply low-temperature air for a long time by using a plurality of ventilation systems in order.

The defrosting means is optional, and hot gas may be introduced into the evaporator. Further, a separate heater may be provided, and defrosting may be performed by the heater.
Also, warm air may be passed through the ventilation path. Defrosting by simple ventilation is also possible.

The invention according to claim 7 , wherein the cooler is an evaporator of a refrigerator constituting a refrigerating cycle, wherein the refrigerator has two or more evaporators, and switching means for switching between the two or more evaporators. And a hot gas introduction circuit for introducing hot gas into each evaporator, wherein at least one evaporator is used as a cooler of one ventilation system, and at least one other evaporator is a ventilation system of another system. 7. The low-temperature air supply device according to claim 6 , wherein the low-temperature air supply device is used as a cooler.

  According to the present invention, it is possible to perform defrosting of the cooler of at least one other ventilation system while driving one ventilation system to reduce the temperature of the air passing through the ventilation path, It is possible to continuously supply the low-temperature air without stopping.

It is possible to operate the cooler heat exchange with the air passing through the same ventilation path a plurality of coolers selectively, the number of coolers to be operated in response to the required temperature of the air It is desirable to be able to change . That is, the invention according to claim 4 is capable of selectively operating the plurality of coolers that exchange heat with the air passing through the same ventilation path, and requiring the required temperature of the air. The low-temperature air supply device according to claim 3, wherein the number of coolers operated according to the temperature can be changed.

As a result of the arrangement of the cooler whose temperature is lower from the air inlet to the air outlet, the finally required air set temperature is higher than the surface temperature of the cooler arranged most downstream. In some cases. In short, the maximum cooling capacity of the low-temperature air supply device may be excessive with respect to the required cold heat.
In such a case, some of the coolers are turned off. For example, from the cooler at the uppermost stream to the cooler having a surface temperature equal to or lower than the set temperature and having a surface temperature close to the set temperature, the air cooled by the operated cooler is discharged.

The invention according to claim 5 is characterized in that the number of operated coolers is changed by suspending at least the most downstream cooler among the plurality of coolers. It is a low-temperature air supply device.
Cooler heat exchange with the air passing through the same ventilation path a plurality of coolers, including those capable of changing the cooling capacity, it is possible to change the cooling capacity according to the conditions desirable.

The “condition” includes, for example, the level of air temperature required for the low-temperature air supply device. When the temperature of the air required for the low-temperature air supply device is relatively high, the cooling capacity is increased, and when the required temperature of the air is relatively low, the cooling capacity is reduced. Similarly, when the required amount of air is relatively large, the cooling capacity is increased, and when the required amount of air is relatively small, the cooling capacity is reduced. When the outside air temperature is high and the temperature of the air introduced into the low-temperature air supply device is relatively high, the cooling capacity is increased, and when the outside air temperature is low, the cooling capacity is reduced.
The present invention is also a low-temperature air supply device capable of coping with a case where the maximum cooling capacity of the low-temperature air supply device is excessive with respect to required cold heat.

Changing the cooling capacity, it is desirable that performed by changing the cooling capacity of at least the most downstream of the cooler of the plurality of coolers to be operated.
According to a ninth aspect of the present invention, there is provided an environmental test apparatus including the low-temperature air supply device according to any of the first to eighth aspects.

  According to the present invention, it is possible to perform an environmental test using a device that consumes air as a device under test.

  The low-temperature air supply device and the environmental test device of the present invention can continuously supply low-temperature air to equipment that consumes air, and consume relatively little power.

It is a conceptual diagram of the environmental test device of the embodiment of the present invention. FIG. 2 is a piping diagram of a refrigerator used in the low-temperature air supply device of the environmental test device of FIG. 1. FIG. 3 is a piping diagram of the refrigerator illustrated in FIG. 2, illustrating a flow of a refrigerant in a case where low-temperature air is supplied using a first ventilation passage. FIG. 3 is a piping system diagram of the refrigerator illustrated in FIG. 2, illustrating a flow of a refrigerant in a case where low-temperature air is supplied using a second air passage. It is a conceptual diagram of the low-temperature air supply device prototyped.

Hereinafter, embodiments of the present invention will be further described.
The environmental test device 1 shown in FIG. 1 includes a test room 2 and a low-temperature air supply device 3. The test room 2 is a room in which a DUT is placed, and can be adjusted to a desired environment by an air conditioner (not shown). A test object (not shown) is arranged in the test room 2. The device under test is a device that consumes air, such as an engine or a burner.

The low-temperature air supply device 3 supplies low-temperature air to the DUT in the test chamber 2.
In the present embodiment, the low-temperature air supply device 3 includes a main body device 10, a pre-dehumidification device 11, and a main dehumidification device 12. Further, it has a blower 13 for supplying air to the low-temperature air supply device 3.

The pre-dehumidifier 11 is the same as that described above, is a water-cooled cooling passage, and dehumidifies air slightly.
The dehumidifier 12 is a normal cooling type dehumidifier, and has a built-in refrigerator 15 therein. The dehumidifier 12 includes a refrigerator 15, controls the surface temperature of the evaporator (not shown) of the refrigerator 15 to be equal to or lower than the dew point temperature of the passing air, and dehumidifies the air by dew condensation on the surface of the evaporator. Things.
The dehumidifier 12 cannot reduce the air humidity as low as the desiccant dehumidifier described above. However, the dehumidifier 12 consumes less power relative to the amount of dehumidification than the desiccant dehumidifier.

Next, the main device 10 will be described.
The main unit 10 has a joint air introduction section 20 and a joint air discharge section 21, and the middle thereof is divided into two ventilation passages 25 a and 25 b by an entrance branch passage 23 and an exit merge passage 22. Hereinafter, one is referred to as a first ventilation path 25a, and the other is referred to as a second ventilation path 25b.
The two ventilation passages 25a and 25b have air introduction parts 26a and 26b and air discharge parts 27a and 27b, respectively.
The ventilation passages 25a and 25b are cylindrical bodies formed by ducts and pipes, and are elongated spaces that communicate the air introduction portions 26a and 26b and the air discharge portions 27a and 27b.
The main unit 10 is provided with a flow path switching unit 28 for switching between the two ventilation paths 25a and 25b. The flow path switching means 28 is constituted by entrance-side switching means 30a, 30b and exit-side switching means 31a, 31b.
The entrance-side switching means 30a and 30b are located near the respective air introduction portions 26a and 26b and at the upstream ends of the ventilation passages 25a and 25b. On the other hand, the outlet-side switching means 31a and 31b are located in the air discharge portions 27a and 27b, and are located at the downstream ends of the ventilation passages 25a and 25b.
In the present embodiment, the entrance-side switching units 30a and 30b and the exit-side switching units 31a and 31b are on-off valves such as butterfly valves and damper valves, and are opened and closed by a motor 32.
The ventilation paths 25a and 25b are both covered with a heat insulating material (not shown).

The main body device 10 of the present embodiment has four independent refrigerators 35A, 35B, 35C, and 35D.
The circuits of the refrigerators 35A, 35B, 35C, 35D are the same, and each has two evaporators 40.
For convenience of explanation, the evaporators belonging to the refrigerators 35A, 35B, 35C and 35D are denoted by capital letters A, B, C and D. When distinguishing the two evaporators 40 belonging to the respective refrigerators 35A, 35B, 35C, and 35D, small letters a and b are added.
In the present embodiment, the evaporator 40 functions as a cooler inserted into the ventilation passages 25a and 25b.

FIG. 2 shows a refrigeration circuit of the refrigerator 35. The refrigerator 35 has a compressor 36, a condenser 37, expansion means 38, a first evaporator 40a, and a second evaporator 40b, which are connected by a refrigerant pipe and filled with a phase-change refrigerant. Things.
In the present embodiment, the compressor 36 is inverter-controlled, and can change the rotation speed.

The refrigerant pipe of the refrigerator 35 includes a main pipe 41, a branch pipe 43, and a hot gas introduction pipe 46.
The main pipe 41 of the refrigerator 35 is a pipe that annularly connects the compressor 36, the condenser 37, the expansion means 38, and the evaporator unit 42. The evaporator unit 42 is a portion where the first evaporator 40a and the second evaporator 40b are provided in parallel.

The branch pipe 43 is a pipe that switches between the first evaporator 40a and the second evaporator 40b of the evaporator unit 42. The branch pipe 43 connects two evaporators 40a and 40b in parallel with the main pipe 41. ing.
That is, the downstream side of the expansion means 38 is branched by the upstream branch pipes 43a and 43b, and connected to the evaporators 40a and 40b, respectively. The upstream branch pipes 43a and 43b are provided with evaporator upstream opening / closing valves 45a and 45b, respectively.

Downstream branch pipes 43c and 43d are connected to the downstream sides of the two evaporators 40a and 40b, respectively, and they are merged and connected to the suction side of the compressor 36.
The downstream branch pipes 43c and 43d are provided with evaporator downstream opening / closing valves 47a and 47b, respectively.
In the present embodiment, switching means for switching between the two evaporators 40a and 40b is configured by the evaporator upstream opening / closing valves 45a and 45b and the evaporator downstream opening / closing valves 47a and 47b.

The hot gas introduction pipe 46 connects the discharge side of the compressor 36 and the introduction sides of the evaporators 40a and 40b, and connects the discharge side of the evaporators 40a and 40b and the suction side of the compressor 36.
That is, the branch between the discharge side of the compressor 36 and the condenser 37 is further branched by hot gas branch pipes 51a and 51b, which are connected to the evaporators 40a and 40b, respectively. The upstream hot gas branch pipes 51a and 51b are provided with hot gas on-off valves 52a and 52b, respectively.
In the present embodiment, a hot gas introduction circuit that introduces hot gas into the two evaporators 40a and 40b is configured by the hot gas introduction pipe 46.

  The refrigerator 35 drives the compressor 36 to circulate the refrigerant, thereby realizing a refrigeration cycle in the circuit and lowering the surface temperatures of the evaporators 40a and 40b. Further, by switching the switching means constituted by the evaporator upstream opening / closing valves 45a, 45b and the evaporator downstream opening / closing valves 47a, 47b, the refrigerant (liquid phase or gas-liquid mixing) is applied to only one of the evaporators 40a, 40b. Phase) can be introduced.

  Hot gas can be introduced into the evaporators 40a and 40b by the hot gas introduction pipe 46. By switching the hot gas on-off valves 52a, 52b, hot gas can be introduced into only one of the evaporators 40a, 40b.

  More specifically, as shown in FIG. 3, the upstream branch pipe 43a of the branch pipe 43 reaching the first evaporator 40a, and the evaporator downstream open / close valve of the flow path returning to the compressor 36 from the first evaporator 40a. 47a is opened, a series of circulation passages passing through the first evaporator 40a are opened, and a refrigerant (liquid phase or gas-liquid mixed phase) is introduced into the first evaporator 40a to lower the surface temperature of the first evaporator 40a. Can be done.

  Also, at this time, the hot gas opening / closing valve 52b of the hot gas introduction pipe 46 leading to the second evaporator 40b is opened to introduce hot gas into the second evaporator 40b, thereby increasing the surface temperature of the second evaporator 40b to remove the hot gas. Frost can be done.

Conversely, as shown in FIG. 4, a series of circulation channels passing through the second evaporator 40b is opened to introduce a refrigerant (liquid phase or gas-liquid mixed phase) into the second evaporator 40b, Surface temperature can be lowered.
At this time, the hot gas opening / closing valve 52a of the hot gas introduction pipe 46 leading to the first evaporator 40a is opened to introduce hot gas into the first evaporator 40a, thereby increasing the surface temperature of the first evaporator 40a and removing the hot gas. Frost can be done.

The main unit 10 of the present embodiment has four independent refrigerators 35A, 35B, 35C, 35D as described above, and each of the refrigerators 35A, 35B, 35C, 35D is provided with a first evaporator 40a. And a second evaporator 40b.
The main body device 10 of the present embodiment has the two air passages 25a and 25b as described above. The respective evaporators 40 of the refrigerators 35A, 35B, 35C, 35D are incorporated in the ventilation passages 25a, 25b one by one.
Specifically, the first evaporator 40a of each of the refrigerators 35A, 35B, 35C, 35D is built in the first ventilation passage 25a. In the second ventilation passage 25b, second evaporators 40b of the refrigerators 35A, 35B, 35C, and 35D are incorporated.

Here, the main unit 10 of the present embodiment has four refrigerators 35A, 35B, 35C, and 35D, and the piping system of each of the refrigerators 35A, 35B, 35C, and 35D is the same. The set temperature of the evaporator 40 differs for each machine 35.
That is, in each of the refrigerators 35A, 35B, 35C, and 35D, the opening degree of the expansion means 38 and the like are different, and the evaporation pressure of the refrigerant in the evaporator 40 is different. As a result, each evaporator 40 has a different surface temperature.
Specifically, the set temperature of each evaporator 40 is different. That is, the set temperature of the refrigerator 35A is the highest, then the refrigerator 35B is high, then the refrigerator 35C is high, and the refrigerator 35D is the lowest.
The evaporators 40 of the refrigerators 35A, 35B, 35C, 35D are arranged in the respective ventilation passages 25a, 25b such that the lower the temperature is, the lower the set temperature is and the lower the surface temperature is. ing.

As described above, the evaporator 40 belonging to the refrigerator 35A is referred to as an evaporator 40A for convenience of explanation. Similarly, the evaporator 40 belonging to the refrigerator 35B is displayed as the evaporator 40B, the one belonging to the refrigerator 35C is displayed as the evaporator 40C, and the one belonging to the refrigerator 35D is displayed as the evaporator 40D.
Then, the first evaporator of each refrigerator 35 is displayed as 40Aa, 40Ba, 40Ca, and 40Da. The second evaporator of each refrigerator 35 is indicated as 40Ab, 40Bb, 40Cb, and 40Db.
Paying attention to the evaporators 40Aa, 40Ba, 40Ca, and 40Da incorporated in the first ventilation passage 25a, evaporators having a lower set temperature from the air inlet 26a to the air outlet 27a and having a lower temperature are arranged. ing.
Specifically, the evaporator 40Aa, the evaporator 40Ba, the evaporator 40Ca, and the evaporator 40Da are arranged in this order from the air introduction part 26a side.
Each of the evaporators 40 is in the first ventilation passage 25a, and the air passing through the ventilation passage 25a directly contacts and exchanges heat.

  The same applies to the second ventilation passage 25b. The evaporators 40Ab, 40Bb, 40Cb, and 40Db built in the second ventilation passage 25b have a lower set temperature from the air inlet 26b to the air outlet 27b, and have their own temperatures. The lower evaporator 40 is arranged.

The low-temperature air supply device 3 of the present embodiment has the main device 10, the pre-dehumidifier 11 and the main dehumidifier 12, as described above.
In the low-temperature air supply device 3 of the present embodiment, a pre-dehumidification device 11, a main dehumidification device 12, and a main device 10 are arranged from the upstream side. The ventilation passages inside the pre-dehumidifier 11, the main dehumidifier 12, and the main unit 10 are connected.

Next, the function of the low-temperature air supply device 3 of the present embodiment will be described.
The operation of each unit will be described on the assumption that a test of a test object such as an engine or a burner requires air at minus 40 degrees.
In the present embodiment, in each of the ventilation passages 25a and 25b, the lower ones on the downstream side are arranged so that their own surface temperature becomes lower, and the evaporators 40Da, 40e of the refrigerator 35D arranged at the most downstream side. The surface temperature of 40Db is the lowest. Then, the temperatures of the evaporators 40Da and 40Db are set such that the surface temperature of the evaporators 40Da and 40Db arranged at the most downstream side is lower than at least the target temperature of air, minus 40 degrees. For example, the surface temperature of the evaporators 40Da and 40Db arranged at the most downstream is set to minus 45 degrees.
For example, the surface temperatures of the upstream evaporators 40Aa and 40Ab disposed closest to the air introduction sections 26a and 26b are set to minus 15 degrees, and the surface temperatures of the middle evaporators 40Ba and 40Bb are respectively minus. The temperature is set to 25 degrees, the surface temperatures of the third evaporators 40Ca and 40Cb are each set to minus 35 degrees, and the surface temperatures of the most downstream evaporators 40Da and 40Db are set to minus 45 degrees.

The low-temperature air supply device 3 of the present embodiment has two ventilation passages 25a and 25b. In an actual environmental test, the ventilation passage 25 is operated one system at a time, and the other system performs a defrosting operation.
If low-temperature air is supplied through the first ventilation path 25a, the switching means 30a, 30b and the switching means 31a, 31b are switched, and the joint air introduction unit 20, the first ventilation path 25a, The three members of the joint air discharge part 21 are communicated, and the second ventilation path 25b is closed.
Specifically, the entrance-side switching unit 30a and the exit-side switching unit 31a belonging to the first ventilation passage 25a are opened, and the entrance-side switching unit 30b and the exit-side switching unit 31b belonging to the second ventilation passage 25b are closed.
As a result, the pre-dehumidifying device 11, the main dehumidifying device 12, and the first ventilation passage 25a of the main body device 10 sequentially form a ventilation passage from the upstream side.

  Each of the refrigerators 35A, 35B, 35C, and 35D allows the refrigerant (liquid phase or gas-liquid mixed phase) to flow through the first evaporator 40a as shown in FIG. It is not necessary to flow hot gas into the second evaporator 40b immediately after the start of the test.

In this state, the blower 13 is started, and air is flowed through a series of ventilation passages formed by the pre-dehumidification device 11, the main dehumidification device 12, and the first ventilation passage 25a of the main device 10.
The air discharged from the blower 13 enters the pre-dehumidifier 11 and is dehumidified. Further, the air dehumidified by the pre-dehumidifier 11 flows to the main dehumidifier 12, and is further dehumidified by the main dehumidifier 12.
Here, since the present dehumidifier 12 is a normal cooling type dehumidifier for dehumidifying by the refrigerator 15, thorough dehumidification cannot be performed. On the other hand, it consumes less power than desiccant dehumidifiers.

  The air dehumidified by the dehumidifier 12 enters the first ventilation passage 25a of the low-temperature air supply device 3, and comes into contact with the evaporator 40Aa disposed on the most upstream side. Then, the passing air exchanges heat with the evaporator 40Aa, and the temperature decreases to a temperature close to the surface temperature of the evaporator 40Aa.

  The air that has passed through the first evaporator 40Aa flows downstream, and comes into contact with the secondly installed evaporator 40Ba. Although the temperature of the air flowing through the middle part of the ventilation passage is lower than the air initially introduced, the surface temperature of the second evaporator 40Ba installed is lower than the surface temperature of the previous evaporator 40Aa. Therefore, the surface temperature of the second evaporator 40Ba is considerably lower than the temperature of the air passing therethrough, so that heat is removed from the passing air, and the temperature of the air is further reduced.

  The air that has passed through the second evaporator 40Ba flows downstream, and comes into contact with the third evaporator 40Ca. Although the temperature of the air flowing through the middle part of the ventilation passage is considerably lowered, the surface temperature of the third evaporator 40Ca is lower than the surface temperature of the evaporator 40Ba. Therefore, the surface temperature of the third evaporator 40Ca is considerably lower than the temperature of the air passing therethrough, so that heat is removed from the air passing therethrough, and the temperature of the air is further reduced.

The air that has passed through the third evaporator 40Ca flows downstream, and comes into contact with the evaporator 40Da installed at the most downstream. Although the temperature of the air flowing through the ventilation passage has dropped considerably, the surface temperature of the evaporator 40Da installed at the most downstream is lower than the surface temperature of the previous evaporator 40Ca. Therefore, the surface temperature of the evaporator 40Da installed at the most downstream is considerably lower than the temperature of the air passing therethrough, so that heat is taken from the air passing therethrough, the temperature of the air is further reduced, and Reach.
As described above, in the present embodiment, the air flowing in one direction through the first ventilation passage 25a comes into contact with the evaporator 40 having a lower temperature one after another, and the temperature gradually decreases.

The air that has passed through the evaporator 40Da at the most downstream reaches the combined air discharge unit 21 from the air discharge unit 27a, and is supplied to the DUT in the test chamber 2.
When the test is performed and time elapses, frost is generated in each evaporator 40a in the first ventilation passage 25a, and the frost grows. However, the surface temperature of each evaporator 40 is lower than the passing air by a certain temperature, and is not excessively low with respect to the passing air. Therefore, the frost does not occur locally but grows uniformly on each evaporator 40. Therefore, it takes a considerable amount of time until the frost grows until it becomes unusable, and the first ventilation path 25a can be used for a relatively long time.

When the frost grows and the heat exchange efficiency decreases, the ventilation passage 25 to be used is switched to the second ventilation passage 25b.
That is, by switching the entrance-side switching means 30a, 30b and the exit-side switching means 31a, 31b, the three members of the joint air introduction part 20, the second ventilation passage 25b, and the joint air discharge part 27b communicate with each other, and the first ventilation The road 25a is closed.
Specifically, the entrance-side switching unit 30b and the exit-side switching unit 31b belonging to the second ventilation passage 25b are opened, and the entrance-side switching unit 30a and the exit-side switching unit 31a belonging to the first ventilation passage 25a are closed.

  Further, each of the refrigerators 35A, 35B, 35C, and 35D allows a refrigerant (liquid phase or gas-liquid mixed phase) to flow through the second evaporator 40b as shown in FIG. Further, hot gas is passed through the first evaporator 40a of each of the refrigerators 35A, 35B, 35C, 35D.

In this state, the blower 13 is started to flow air through a series of ventilation paths.
The air discharged from the blower 13 passes through the dehumidifier 12 from the pre-dehumidifier 11 and enters the second ventilation passage 25b of the low-temperature air supply device 3, and the evaporators 40Ab, 40Bb, The sample is cooled by 40Cb and 40Db sequentially, and is sent to the test room 2 at a target low temperature.

At the same time, hot gas is introduced into each of the evaporators 40Aa, 40Ba, 40Ca, and 40Da incorporated in the first ventilation path 25a, and the surface temperature of each of the evaporators 40Aa, 40Ba, 40Ca, and 40Da rises. Frost attached to the surfaces of the vessels 40Aa, 40Ba, 40Ca, and 40Da melts.
When the frost has sufficiently melted, the introduction of the hot gas is stopped and the first ventilation path 25a is put on standby.

In the low-temperature air supply device 3 of the present embodiment, since the surface temperatures of the evaporators 40Aa and 40Ab on the most upstream side are about minus 15 degrees Celsius, the coefficient of performance of the refrigerator 35A is about 1.5 to 2.0. Can be expected.
Since the surface temperature of the next evaporators 40Ba and 40Bb is minus 25 degrees, the coefficient of performance of the refrigerator 35B can be expected to be about 1.4 to 1.6.
Since the third evaporators 4Ca and 40Cb have a surface temperature of minus 35 degrees, the coefficient of performance of the refrigerator 35C can be expected to be about 1.2 to 1.4.
The lowermost evaporators 40Da and 40Db have low surface temperatures and cannot expect a good coefficient of performance.
However, among the four refrigerators 35A, 35B, 35C, and 35D, three of them have good coefficients of performance, so that the efficiency as a whole is high and the power consumption is expected to decrease.

  In this embodiment, since it is not necessary to use a desiccant dehumidifier, the power consumption is also low in this respect.

In the embodiment described above, four refrigerators 35A, 35B, 35C, 35D are provided and all the refrigerators 35A, 35B, 35C, 35D are used. However, if the required temperature of the air is not so low, several refrigerators 35A, 35B, 35C, 35D are used. Some of the refrigerators 35A, 35B, 35C, 35D may be used and some of them may be stopped.
For example, if the required air temperature is minus 30 degrees, three refrigerators 35A, 35B, and 35C are driven, and the lowermost refrigerator 35D is stopped.
If the required temperature is low but the required air volume is small, the upstream refrigerator 35A may be stopped and the refrigerators 35B, 35C, and 35D at or below the middle flow may be driven.
Of course, only the middle refrigerator 35 may be used.

In short, the total cooling capacity of each of the refrigerators 35A, 35B, 35C, 35D may be excessive with respect to the required cold heat.
In such a case, some of the refrigerators 35 near the end are stopped. For example, the refrigeration in which the surface temperature of the evaporator 40 is equal to or lower than the temperature of the discharge air required for the low-temperature air supply device 3 and the surface temperature becomes the temperature closest to the required temperature from the cooler 35A at the most upstream position. The refrigerator 35 is operated to discharge air cooled by the operated refrigerator group.

In this embodiment, since the compressor 36 is controlled by the inverter and the rotation speed can be changed, the output of the compressor is changed so as to exert an appropriate refrigeration capacity according to the required temperature and air volume. can do.
The fine adjustment of the temperature of the air discharged from the low-temperature air supply device 3 is desirably performed by adjusting the output of the compressor 36 of the refrigerator 35 on the most downstream side of the driven refrigerators.

In the embodiment described above, four evaporators 40 as coolers are arranged in series in the ventilation passage 25, but the number of evaporators 40 is arbitrary, and five or more evaporators 40 are arranged. You may.
Conversely, the number of evaporators 40 may be three or less. The number of evaporators 40 may be two or more, but it is recommended to have three or more evaporators 40.

  In the embodiment described above, the cooler installed in the ventilation passages 25a and 25b is the evaporator 40 of the refrigerator 35. However, the cooler that passes through the brine and lowers the surface temperature to the set temperature is used. Is also good.

  In the above-described embodiment, the ventilation passages 25a and 25b are formed by ducts or pipes, but the ventilation passages 25a and 25b may be divided into a plurality of sections. For example, the ventilation passages 25a and 25b may be a collection of a plurality of thin tubes. That is, the ventilation passages 25a and 25b may be a bundle of tubes in which a plurality of tubes and the like are arranged in parallel.

Although the low-temperature air supply device 3 of the above-described embodiment has two systems of the ventilation passages 25a and 25b, the ventilation passage 25 may have one system. Further, three or more ventilation passages 25 may be provided.
When defrosting each ventilation path 25, the ventilation environment may be a ventilation environment.

  In the above-described embodiment, the defrosting is performed by flowing the hot gas into the evaporator 40 that is not in operation, but the defrosting method is not limited to the method using the hot gas. For example, a heater may be provided in the evaporator 40, and defrosting may be performed by the heater. Further, warm air may be passed through the ventilation passage 25. Defrosting is also possible by passing normal-temperature air through the ventilation passage 25.

DESCRIPTION OF SYMBOLS 1 Environmental test apparatus 2 Test room 3 Low temperature air supply apparatus 10 Main unit 25a First ventilation path 25b Second ventilation path 35A, 35B, 35C, 35D Refrigerators 40Aa, 40Ba, 40Ca, 40Da First evaporators 40Ab, 40Bb, 40Cb , 40Db Second evaporator 45a, 45b Evaporator upstream opening / closing valve (switching means)
47a, 47b On-off valve on the downstream side of the evaporator (switching means)

Claims (9)

A low-temperature air supply device that unilaterally supplies air to a supply target,
A series of ventilation paths from the air introduction section to the air discharge section, having a plurality of coolers capable of cooling the air passing through the ventilation path ,
The plurality of coolers can lower their temperature and exchange heat with the air passing through the ventilation path, and reduce the temperature of the air passing through the ventilation path,
A cooler having its own lower temperature is arranged from the air inlet to the air outlet,
What der least in two or more coolers are simultaneously driven among the plurality of coolers,
It is possible to change the number of coolers operated according to the required air temperature,
The change in the number of the coolers to be operated is, when the total cooling capacity of the plurality of coolers is excessive with respect to the required temperature of the air, from the cooler on the downstream side among the plurality of coolers. cold air supply device according to claim Rukoto performed by pause. The plurality of coolers include those capable of changing the cooling capacity, it is possible to change the cooling capacity according to conditions,
2. The low-temperature air supply device according to claim 1, wherein the change of the cooling capacity is performed by changing a cooling capacity of at least a most downstream cooler among the plurality of operated coolers. 3. A low-temperature air supply device that unilaterally supplies air to a supply target,
A series of ventilation paths from the air introduction section to the air discharge section, having a plurality of coolers capable of cooling the air passing through the ventilation path,
The plurality of coolers can lower their temperature and exchange heat with the air passing through the ventilation path, and reduce the temperature of the air passing through the ventilation path,
A cooler having its own lower temperature is arranged from the air inlet to the air outlet,
At least two or more coolers of the plurality of coolers are simultaneously driven,
The plurality of coolers include those capable of changing the cooling capacity, it is possible to change the cooling capacity according to the conditions,
The low-temperature air supply device according to claim 1, wherein the cooling capacity is changed by changing a cooling capacity of a most downstream cooler among the plurality of operated coolers. It is possible to selectively operate a plurality of coolers that exchange heat with air passing through the same ventilation path, and to reduce the number of coolers to be operated according to the required temperature of air. 4. The low-temperature air supply device according to claim 3, wherein the low-temperature air supply device can be changed.
5. The low-temperature air supply device according to claim 4, wherein the number of the coolers to be operated is changed by suspending at least a most downstream cooler among the plurality of coolers. While having a plurality of ventilation systems having the series of ventilation paths and the plurality of coolers, while driving at least one ventilation system to reduce the temperature of the air passing through the ventilation paths, at least another The low-temperature air supply device according to any one of claims 1 to 5, wherein defrosting of a cooler of one ventilation system is possible. The cooler is an evaporator of a refrigerator constituting a refrigeration cycle,
The refrigerator has two or more evaporators, switching means for switching the two or more evaporators, and a hot gas introduction circuit for introducing a hot gas into each evaporator,
At least one evaporator is used as a cooler for ventilation system of one system, according to claim 6, characterized in that at least another one of the evaporator is used as a cooler for ventilation systems of other strains Low temperature air supply equipment. The low-temperature air supply device according to any one of claims 1 to 7, wherein three or more coolers are provided for one ventilation path. Environmental testing apparatus having a cold air supply device according to any one of claims 1 to 8.

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