JP5487167B2 - Environmental test equipment - Google Patents

Description

  The present invention relates to an environmental test apparatus, and is particularly suitable as an environmental test apparatus for performing a thermal shock test.

Environmental tests may be performed to inspect the durability of products and parts. In the environmental test, a test object is exposed to a harsh environment, and changes in performance and quality are examined.
One environmental test is a thermal shock test.
In the thermal shock test, a test object in a high temperature state or a state close to normal temperature is rapidly cooled to give thermal stress.
In the thermal shock test, a high-temperature exposure test in which the DUT is exposed to a high-temperature environment and a low-temperature exposure test in which the DUT is exposed to a low-temperature environment are alternately performed. There is a three-zone test that puts a period for returning to normal temperature during the exposure test or between the low temperature exposure test and the high temperature exposure test.

An apparatus used when performing a thermal shock test is, for example, as disclosed in FIG. 4 of Patent Document 1 or Patent Document 3, and stores a test chamber in which a test object is installed and hot air. It has a preheating chamber for storing and a precooling chamber for storing low-temperature air. An open / close damper is provided between the test chamber and the preheating chamber and between the test chamber and the precooling chamber.
When a high temperature exposure test is performed, a damper between the test chamber and the preheating chamber is opened, and the high temperature air stored in the preheating chamber is passed through the test chamber. In the subsequent low temperature exposure test, the open / close damper between the test chamber and the pre-cooling chamber is opened, and the low-temperature air stored in the pre-cooling chamber is allowed to flow through the test chamber.

  Another example of an apparatus for performing a thermal shock test is one having a structure as disclosed in Patent Document 2. The apparatus disclosed in Patent Document 2 has a high-temperature chamber for storing high-temperature air and a low-temperature chamber for storing low-temperature air, and the device under test moves between them.

  Since the thermal shock test gives a test object a thermal shock, it is desirable that the test temperature in the low temperature exposure test is considerably lower than the environmental temperature before the low temperature exposure test is performed. Therefore, it is necessary for the thermal shock test to create a considerably low environment, and the cooling device is often provided with a binary refrigeration circuit in which two refrigeration circuits are thermally coupled via a cascade capacitor.

JP 2009-264896 A JP 2006-329949 A JP 2006-329827 A

In the thermal shock test, as described above, the test object is rapidly cooled to give a thermal shock to the test object, and therefore the mounted cooling device must be of a large capacity. That is, in the thermal shock test, a cooling device having a larger output than that of a normal constant temperature and humidity device is mounted.
Therefore, an environmental test apparatus that performs a thermal shock test has a large amount of power consumption and has been desired to be improved.

  Therefore, the present invention focuses on the above-described problems of the prior art, and an object of the present invention is to provide an environmental test apparatus with low power consumption.

The invention described in claim 1 for solving the above-described problem is an environmental test apparatus that has a cooling device and can create a low temperature environment of a target temperature in a predetermined space, and the cooling device includes: It has a dual cooling structure with a primary side cooling circuit and a secondary side cooling circuit, and the primary side cooling circuit has a high temperature side compression part, a high temperature side condensing part, a high temperature side expansion means, and a primary side of the cascade condenser arranged in an annular pattern sequentially. The secondary-side cooling circuit has a low-temperature side compression section, a secondary side of the cascade condenser, a low-temperature side expansion means, and a low-temperature side evaporator arranged in a circular pattern in order. In the environmental test apparatus, in which the phase change refrigerant is circulated, the low temperature side compression section of the secondary side cooling circuit has two or more compressors, which are connected in parallel. Is what Operation in full operation mode where all compressors operate and all compressors contribute to environmental temperature adjustment, and only some compressors operate and only some compressors contribute to environmental temperature adjustment and other compressor Ri can der operation with energy saving operation mode which does not contribute to the adjustment of the ambient temperature, the low temperature side expansion means refrigerant temperature of the refrigerant at a position on the downstream side of the predetermined than its near or cold side expansion means The opening degree is adjusted so as to be a set temperature, and the relationship between the actual temperature of the predetermined space and the refrigerant set temperature is associated with the predetermined relationship in advance, and in the full operation mode and the energy saving operation mode In this case, the relationship is changed .

The cooling device employed in the environmental test apparatus of the present invention has a dual cooling structure and can create a cryogenic temperature.
Moreover, the environmental test apparatus of this invention mounts two or more compressors in the low temperature side of a cooling device, and connected this in parallel.
And all compressors operate and all compressors contribute to the adjustment of the environmental temperature, operation in full operation mode, and only some of the compressors operate and only some of the compressors adjust the environmental temperature. Other compressors that contribute and can use energy-saving operation modes that do not contribute to the adjustment of the environmental temperature. That is, in the thermal shock test, the demand for thermal energy changes with time, and the amount of change is large. According to the present invention, the operation in the full operation mode and the operation in the energy saving operation mode can be properly used, and cold energy as required can be obtained.
For ease of explanation, assuming that two compressors are mounted on the cooling device, one compressor is called a main compressor and the other is called an auxiliary compressor.
In the environmental test apparatus of the present invention, for example, during the low temperature exposure operation, until the temperature in the test chamber reaches the target temperature, the two compressors are operated to contribute to cooling, and the temperature in the test chamber is After reaching the target temperature, the temperature of the test chamber is maintained only by the remaining one compressor (main compressor) after resting one compressor (auxiliary compressor).
In other words, the low temperature exposure in the thermal shock test is to place the test object in a low temperature environment and rapidly cool the test object in a high temperature state or a medium temperature state. Therefore, until the temperature of the test object matches the environmental temperature. In order to lower the temperature of the DUT, a lot of cold energy is required. Therefore, a lot of cooling energy is required until the environment in which the DUT is placed matches the target temperature.
On the other hand, the cooling energy required after the temperature of the DUT matches the environmental temperature is sufficient to absorb the disturbance, and is significantly smaller than the former.
Therefore, in the present invention, two or more compressors (main compressor and auxiliary compressor) are mounted on the cooling device, and the compressors are operated only for the required number to save energy.

In the first aspect of the present invention, the opening degree of the low temperature side expansion means is adjusted so that the temperature of the refrigerant in the vicinity or downstream of the low temperature side expansion means becomes a predetermined refrigerant set temperature. The relationship between the actual temperature of the predetermined space and the refrigerant set temperature is associated with the predetermined relationship in advance, and the relationship is changed between the full operation mode and the energy saving operation mode. To do.

Here, the predetermined relationship may be, for example, a one-to-one correspondence relationship, or a correspondence relationship between a case where the temperature of the space tends to increase and a case where the temperature tends to decrease. Moreover, the relationship replaced by a fixed function may be sufficient.
If there are two compressors as in the previous example, and the outputs of the two compressors are the same, the refrigerant discharge amount in the full operation mode is the same as in the energy saving operation mode. Double the case.
Therefore, the amount of refrigerant passing through the low temperature side expansion means is doubled between both operations. Therefore, if the open / close control of the low temperature side expansion means is made the same between the two operations, there is a concern that liquid return may occur on the compressor side, or the refrigerant supplied to the cascade capacitor may be extremely reduced. .
Therefore, in the present invention, the relationship between the actual temperature in the predetermined space and the refrigerant set temperature is changed between the full operation mode and the energy saving operation mode.

In the invention described in claim 2 , the environmental test apparatus performs a thermal shock test, and it is possible to perform a low-temperature exposure operation in which a high-temperature or intermediate-temperature test object is exposed to a low-temperature environment of a target temperature. Yes, during the low temperature exposure operation, the test environment where the DUT is placed reaches the low temperature environment of the target temperature or the temperature in the vicinity. The environmental test apparatus according to claim 1 , wherein the operation is performed in an energy saving operation mode after reaching the point.

Here, the “intermediate temperature state” is a temperature range that is touched by a person around normal temperature.
“Near the low temperature environment of the target temperature” includes the case where the temperature drops from the high temperature side and approaches the “target temperature” to some extent, or the case where the temperature drops from the high temperature side and falls below the “target temperature”. . Furthermore, when the temperature drops from the high temperature side to the “target temperature” and a certain period of time elapses or a certain degree of stability is maintained, it is included in the “near the low temperature environment of the target temperature”.
According to the present invention, when the conditions are satisfied, such as when the test environment reaches a low temperature environment of the target temperature, the operation in the energy saving operation mode is performed. Therefore, according to the present invention, power consumption can be suppressed.

In the invention described in claim 3 , the environmental test apparatus performs a thermal shock test, and it is possible to perform a low-temperature exposure operation in which a high-temperature or medium-temperature test object is exposed to a low-temperature environment of a target temperature. There is a pre-cooling space for storing low-temperature air until the low-temperature exposure operation is performed, and the pre-cooling space is cooled to maintain the pre-cooling space at the pre-cooling target temperature until the low-temperature exposure operation is performed. It is possible to set a precooling target temperature of the precooling space during the precooling operation. When the precooling target temperature is low, the precooling operation is performed in the full operation mode, and the precooling target temperature is an environmental test apparatus according to claim 1 or 2, characterized in that the precooling operation by the energy saving operation mode when high.

  In the environmental test apparatus of the present invention, when performing the pre-cooling operation, it is determined according to the pre-cooling target temperature whether the operation mode is the full operation mode or the energy saving operation mode.

In the invention described in claim 4 , the environmental test apparatus performs a thermal shock test, and can perform a low temperature exposure operation in which a high-temperature or medium-temperature test object is exposed to a low temperature environment of a target temperature. Yes, it is possible to set the target temperature of the environment where the DUT is placed when performing the low temperature exposure operation, and when the target temperature is higher than the predetermined high temperature side reference temperature, the environment in the test space Is operated in the energy-saving operation mode even when the target temperature is lower than the target temperature, and when the target temperature is lower than the predetermined low temperature side reference temperature, the environment in which the DUT is placed is the target temperature. The environmental test apparatus according to any one of claims 1 to 3 , wherein the operation is performed in a full operation mode even after reaching a low temperature environment.

When the target temperature for low temperature exposure operation is higher than the predetermined high temperature side reference temperature, it is expected that no large amount of cooling energy is required even when the environment in the test space reaches the target low temperature environment. . Therefore, in the present invention, when the target temperature is higher than the predetermined high temperature side reference temperature, the operation in the energy saving operation mode is performed even when the environment in the test space reaches the target low temperature environment.
Further, when the target temperature is lower than a predetermined low temperature side reference temperature, it is expected that a large amount of cooling energy is required even after the environment in which the DUT is placed reaches the target low temperature environment. Therefore, in the present invention, when the target temperature of the low temperature exposure operation is lower than the predetermined low temperature side reference temperature, the full operation mode is set even after the environment in which the DUT is placed reaches the target low temperature environment. Drive by.

The invention according to claim 5 starts the primary side cooling circuit and the secondary side cooling circuit from a state where both the primary side cooling circuit and the secondary side cooling circuit are stopped, and the operation mode at that time is the full operation mode. In this case, the environmental test apparatus according to any one of claims 1 to 4 , wherein the compressors connected in parallel are sequentially started with a time interval.

The present invention has a dual cooling structure including a primary side cooling circuit and a secondary side cooling circuit, and takes away the heat of condensation generated in the secondary side cooling circuit with the evaporation heat of the primary side cooling circuit. Therefore, it is desirable to balance between the heat of evaporation that can be taken away by the primary side cooling circuit and the heat of condensation generated in the secondary side cooling circuit.
However, at a short time after the primary side cooling circuit is started, the heat of evaporation is taken away by the device itself, and the amount of heat that can be cooled by the primary side cooling circuit is not stable.
Therefore, when the primary side cooling circuit and the secondary side cooling circuit are both stopped, the primary side cooling circuit and the secondary side cooling circuit are started, and when the compressors connected in parallel are started simultaneously, the primary side cooling circuit The heat absorption amount is less than the heat generation amount on the secondary side cooling circuit side, and the primary side cooling circuit is overloaded. In the secondary cooling circuit, condensation does not proceed and an abnormal pressure rise occurs. Therefore, in the present invention, when the primary side cooling circuit and the secondary side cooling circuit are started from a state where both the primary side cooling circuit and the secondary side cooling circuit are stopped, and the operation mode at that time is the full operation mode. Starts sequentially the compressors connected in parallel at intervals.

The invention according to claim 6 is that all the compressors in the low-temperature side compression unit are hermetic compressors in which a motor and a pressurizing device are built in a hermetic container, and all the compressors in the low-temperature side compression unit closed container is environmental test apparatus according to any one of claims 1 to 5, characterized in that it is connected by a conduit.

  In the environmental test apparatus of the present invention, since the sealed containers of all the compressors in the low temperature side compression section are connected by the conduit, the oil level in the hermetic compressor is leveled. For this reason, the environmental test apparatus of the present invention is unlikely to cause poor oil lubrication inside the compressor.

The invention according to claim 7 has an operation time integration means, and the operation time integration means adjusts the environmental temperature even in the energy saving operation mode among the two or more compressors of the low temperature side compression section. The main compression that changes the compressor that contributes to the adjustment of the environmental temperature in the energy saving operation mode when the integration time of the operation time integration means reaches a certain time. it is an environment test apparatus according to any one of claims 1 to 6, wherein the includes a machine change function.

As described above, in the environmental test apparatus according to any one of claims 1 to 6 , all the compressors operate in the operation in the “full operation mode”.
On the other hand, in the case of “energy saving operation mode”, “only some compressors operate and only some compressors contribute to the adjustment of the environmental temperature, and other compressors do not contribute to the adjustment of the environmental temperature”. Only some of the compressors are operating and the remaining compressors remain stopped.
As described above, the environmental test apparatus according to any one of claims 1 to 6 has low power consumption and is preferable.
However, in the environmental test apparatus described above, the actual working times of the main compressor and the auxiliary compressor are significantly different, and only the main compressor is consumed. Therefore, the sliding part and the rotating part of the main compressor are easily worn. Moreover, there is a concern that the main compressor may run out of oil, oil stains, and grease.
The invention according to claim 7 pays attention to this fact, and an object thereof is to provide an environmental test apparatus in which the working time of the compressor is made uniform and maintenance management is easy.
The environmental test apparatus of the present invention has an operation time integration means for integrating the operation time of the compressor on the side that contributes to the adjustment of the environmental temperature in the energy saving operation mode.
Here, the “operating time accumulating means” may be an accumulating total operating time of the compressor (the main compressor in the previous example) that contributes to the adjustment of the environmental temperature in the energy saving operation mode. The time which is operated independently may be integrated. That is, the “operating time integrating means” may be the sum of the operating time in the full operation mode and the operating time in the “energy saving operation mode”, or only the operation time in the “energy saving operation mode”. May be.
In the environmental test apparatus of the present invention, when the accumulated time of the operating time integrating means reaches a certain time, the compressor contributing to the adjustment of the environmental temperature is changed in the energy saving operation mode by the main compressor changing function. To explain based on the previous example, the main compressor and the auxiliary compressor are interchanged.
For this reason, the actual working times of the plurality of compressors are smoothed.
According to an eighth aspect of the present invention, the relationship between the actual temperature of the predetermined space and the refrigerant set temperature is such that the refrigerant set temperature is increased when the actual temperature of the predetermined space increases in both the full operation mode and the energy saving operation mode. In the full operation mode and the energy saving operation mode, there is an upper limit for the target temperature of the refrigerant evaporation temperature, and the upper limit in the energy saving operation mode is higher than the upper limit in the full operation mode. It is an environmental test apparatus in any one of Claims 1 thru | or 7.

  In the environmental test apparatus of the present invention, since the number of contributing compressors is changed according to the required amount of cooling heat, there is an effect that power consumption is small.

It is a conceptual diagram which shows the mechanical structure of the thermal shock test apparatus of embodiment of this invention. It is a conceptual diagram which shows the mechanical structure of the thermal shock test apparatus shown in FIG. 1, and shows the state which is implementing high temperature exposure driving | operation. It is a conceptual diagram which shows the mechanical structure of the thermal shock test apparatus shown in FIG. 1, and shows the state which is implementing low-temperature exposure operation. It is a piping system diagram of the cooling device of the thermal shock test apparatus shown in FIG. It is a flowchart explaining operation | movement of the thermal shock test apparatus shown in FIG. It is a time chart which shows the outline of the flow at the time of the start of the thermal shock test implemented with the thermal shock test apparatus of embodiment of this invention, the target temperature of a test chamber is medium low temperature, and a cooling device is continuous. Shows the case of driving. It is a time chart which shows the outline of the flow at the time of the start of the thermal shock test implemented with the thermal shock test apparatus of embodiment of this invention, the target temperature of a test room is a moderate low temperature, and a cooling device is pre-cooling driving | operation The case where it stops temporarily at the time of is shown. It is a time chart which shows the operation | movement at the time of the low temperature exposure operation | movement of the cooling device of the thermal shock test apparatus shown in FIG. 1, and shows the case where the target temperature of a test chamber is a moderate low temperature. FIG. 5 is a graph showing the operation of the low temperature side expansion valve of the cooling device shown in FIG. 4, and shows the relationship between the measured value of the temperature in the test chamber and the target temperature downstream of the evaporation valve. It is a time chart which shows the operation | movement at the time of the low-temperature exposure operation | movement of the cooling device of the thermal shock test apparatus shown in FIG. 1 when the accumulated usage time of a 1st compressor exceeds 1000 hours, and the target temperature of a test chamber is medium The case where the temperature is low is shown. It is a time chart which shows the operation | movement at the time of the low temperature exposure operation | movement of the cooling device of the thermal shock test apparatus shown in FIG. 1, and shows the case where the target temperature of a test chamber is comparatively high. It is a time chart which shows the operation | movement at the time of the low temperature exposure operation | movement of the cooling device of the thermal shock test apparatus shown in FIG. 1, and shows the case where the target temperature of a test chamber is a very low temperature. It is a time chart which shows the operation | movement of the pre-cooling driving | operation of the cooling device of the thermal shock test apparatus shown in FIG. 1, and shows the case where the target temperature of a test chamber is a very low temperature. It is a time chart which shows the operation | movement of the pre-cooling driving | operation of the cooling device of the thermal shock test apparatus shown in FIG. 1, and shows the case where the target temperature of a test chamber is comparatively high. It is a conceptual diagram which shows the mechanical structure of the thermal shock test apparatus of other embodiment of this invention, and shows the state which is implementing high temperature exposure driving | operation. It is a conceptual diagram which shows the mechanical structure of the thermal shock test apparatus shown in FIG. 15, and shows the state which is implementing low-temperature exposure driving | operation. It is a time chart which shows the operation | movement at the time of the low temperature exposure operation | movement of the cooling device of the thermal shock test apparatus of other embodiment of this invention, and shows the case where the target temperature of a test chamber is a moderate low temperature. It is a time chart which shows the operation | movement at the time of the low-temperature exposure operation | movement of a cooling device when the integrated usage time of the 1st compressor of the thermal shock test apparatus of embodiment same as FIG. The case where the temperature is a medium low temperature is shown. It is a piping system diagram of the cooling device of the thermal shock test device of the reference invention.

Embodiments of the present invention will be further described below.
The environmental test apparatus 1 of the present embodiment is specifically a thermal shock test apparatus. Inside the environmental test apparatus 1 of the present embodiment, there is a region surrounded by a heat insulating wall 10, as shown in FIG. 1, there is a test chamber 2 in the center, a precooling chamber (precooling space) 3 around the center, The preheating chamber 5, the introduction side air passage 7, and the discharge side air passage 8 are arranged.
Between the central test chamber 2 and the introduction side air passage 7, there is an air introduction opening 11 made of a plate having a large number of openings such as punching metal, and similarly between the discharge side air passage 8 and the punching metal. There is a blower discharge opening 12 made of a plate having a number of openings such as.
The test chamber 2 is provided with a test chamber temperature detection sensor 6 that detects the temperature in the test chamber 2.

The pre-cooling chamber 3 is a space for producing low-temperature air and storing the low-temperature air, and the low-temperature side evaporator 16 of the cooling device 15 is disposed. The precooling chamber 3 is provided with an auxiliary heater 23. Further, the precooling chamber 3 is provided with a precooling chamber temperature detection sensor 13 for detecting the temperature in the precooling chamber 3. Actually, a blower and various sensors are provided, but detailed description is omitted.
A pre-cooling chamber 3, is provided between the inlet side air passage 7, the cool air introduced dampers over 17. Also a pre-cooling chamber 3, between the discharge-side air flow passage 8, the cold air recovery dampers over 18.

The preheating chamber 5 is a space for creating high-temperature air and storing the high-temperature air, and is provided with a preheating chamber heater 20. Actually, a blower and various sensors are provided, but detailed description is omitted.
A preheating chamber 5, between the inlet side air flow passage 7, hot air introduced dampers over 21. Also between the preheating chamber 5 and the discharge-side air flow passage 8, the hot air recovered dampers over 22.

The environmental test apparatus 1 can alternately perform a high temperature exposure operation and a low temperature exposure operation. The operation at the start of operation of the environmental test apparatus 1 is generally as shown in the time chart of FIG.
That is, as a preparation stage, the cooling device 15 is operated, the air in the precooling chamber 3 is cooled, and the air at the target temperature for the low temperature exposure operation (specifically, the air at the precooling target temperature and the target temperature for the low temperature exposure operation). Is also low). That is, a pre-cooling operation is performed to cool the air in the pre-cooling chamber 3 that is a pre-cooling space, and low-temperature air is stored in the pre-cooling chamber 3. In the present embodiment, the cooling device 15 is operated to cool the air in the precooling chamber 3, but the cooling device 15 is not completely stopped even if the temperature in the precooling chamber 3 reaches the target temperature. That is, in the present embodiment, the cooling device 15 is operated to cool the air in the precooling chamber 3, and when the temperature is excessively lowered, the auxiliary heater 23 is energized to compensate for excessive cooling.
In the environmental test apparatus 1 of this embodiment, in the pre-cooling operation, the temperature in the pre-cooling chamber 3 is controlled to be the pre-cooling target temperature. More specifically, the pre-cooling room temperature detection sensor 13 is monitored and controlled so that the detected temperature becomes the pre-cooling target temperature. In the present embodiment, the precooling target temperature is lower than the target temperature for the low temperature exposure operation.

In addition, the preheating chamber heater 20 is operated to heat the air in the preheating chamber 5 to produce air at the target temperature for the high temperature exposure operation.
Then, a device under test 25 is installed in the test chamber 2.
From this state, it communicates with the preheating chamber 5 opens the hot air introduced dampers over 21 and hot air recovered dampers over 22 as in FIG. 2 and the test chamber 2, by introducing hot air into the test chamber 2 hot Perform exposed operation.

After a certain period of time, close the hot air introduced dampers over 21 and hot air recovered dampers over 22, followed by pre-cooling chamber 3 by opening the cool air introduction dampers over 17 and cool air recovery dampers over 18 as in FIG. 3 and the test It communicates with chamber 2. And low temperature air is introduce | transduced in the test chamber 2, and low temperature exposure driving | operation is implemented.
That is, when communicating the precooling chamber 3 and the test chamber 2 by opening the cool air introduction dampers over 17 and cool air recovery dampers over 18, the temperature in the test chamber 2 as in FIG. 6 go rapidly decreases.
When the low temperature exposure operation is being executed, the cooling device 15 is operated to adjust the inside of the test chamber 2 to the target temperature of the low temperature exposure operation.
Since the cooling device 15 has already been started during the pre-cooling operation as described above, and the low-temperature exposure operation is executed subsequent to the pre-cooling operation, the cooling device 15 does not stop as shown in FIG. Driving continues.
In order to save energy, as shown in FIG. 7, there is a case where the operation of the cooling device 15 is temporarily stopped during the pre-cooling operation. The device 15 is activated. Actually, the operation of the cooling device 15 is started a short time before the low temperature exposure operation is started as shown in FIG. Of course, when the low temperature exposure is started, the operation of the cooling device 15 may be started.

The high temperature exposure operation and the low temperature exposure operation are set as one cycle, and this is repeated a plurality of cycles.
The above series of operations is automatically performed by a program preset in the control device (FIG. 4) 72.

In the environmental test apparatus 1 of the present embodiment, a dual cooling structure as shown in FIG.
That is, the cooling device 15 has a dual cooling structure including a primary side cooling circuit 30 and a secondary side cooling circuit 31.
The primary side cooling circuit 30 includes a high temperature side compression unit 32, a high temperature side oil separator 33, a high temperature side condensing unit 35, a high temperature side expansion means 36, a primary side flow path 38 and a high temperature side accumulator 40 in an annular fashion. It is piped.
And the refrigerant | coolant which changes phase in the above-mentioned circuit is enclosed. Further, a temperature sensor 44 is provided on the outlet side of the primary side flow path 38 of the cascade capacitor 37. The temperature sensor 44 measures the outlet temperature on the primary side of the cascade capacitor 37.
The primary side cooling circuit 30 implement | achieves a refrigerating cycle similarly to the well-known thing.

The secondary side cooling circuit 31 includes a low temperature side compression unit 41, a low temperature side oil separator 42, a secondary side flow path 43 of the cascade condenser 37, a low temperature side expansion means 45, a low temperature side evaporator 16, and a low temperature side accumulator 46 sequentially. It is piped in an annular shape. The bypass flow path 47 is branched between the low temperature side oil separator 42 and the secondary flow path 43 of the cascade condenser 37, and is connected between the low temperature side evaporator 16 and the low temperature side accumulator 46. The bypass channel 47 is a relief channel and is provided with a pressure relief valve 48.
A refrigerant temperature detection sensor 58 is provided on the downstream side of the low temperature side expansion means 45. The low temperature side expansion means 45 is an expansion valve and can adjust an opening degree by an actuator 66 such as a motor. That is, the opening degree of the low temperature side expansion means 45 is adjusted so that the refrigerant temperature detection sensor 58 becomes a predetermined refrigerant set temperature.

That is, as is well known, there is a correlation between the opening of the expansion valve and the like and the evaporation temperature of the refrigerant, and when the opening of the expansion valve and the like is small, the evaporation temperature of the refrigerant is lowered.
Therefore, the low temperature side expansion means 45 is controlled so that the evaporation temperature of the refrigerant becomes a predetermined temperature (refrigerant set temperature). Specifically, when the detected temperature of the refrigerant temperature detection sensor 58 is higher than the refrigerant set temperature, the opening degree becomes small, and when the refrigerant temperature detection sensor 58 is lower than the refrigerant set temperature, the opening degree becomes large.

Further, in the present embodiment, the target temperature (refrigerant set temperature) of the refrigerant evaporation temperature is changed according to the actually measured temperature in the test chamber 2.
That is, the target temperature (refrigerant set temperature) of the refrigerant evaporation temperature changes according to the temperature detected by the test chamber temperature detection sensor 6 provided in the test chamber 2. That is, in this embodiment, the actual temperature of the test chamber 2 and the refrigerant set temperature are associated with a predetermined relationship in advance.
The relationship between the detection temperature of the test chamber temperature detection sensor 6 and the refrigerant set temperature is as shown in the graph of FIG. 9 and is stored in the control device 72 in advance. In the present embodiment, as will be described later, the relationship between the detected temperature of the test chamber temperature detection sensor 6 and the refrigerant set temperature differs between the full operation mode and the energy saving operation mode.

Then, the phase-change refrigerant is enclosed in the secondary side cooling circuit 31 described above. The secondary side cooling circuit 31 realizes a refrigeration cycle in the same manner as a known one.
Similarly to the known dual cooling structure, the refrigerant of the primary side cooling circuit 30 is evaporated in the primary side flow path 38 of the cascade condenser 37 of the primary side cooling circuit 30 to lower the temperature of the cascade condenser 37.
The refrigerant in the secondary side cooling circuit 31 is condensed by the low temperature generated at this time.

  Here, as a configuration unique to the present embodiment, the low temperature side compression unit 41 includes two compressors 50 and 51. That is, the low temperature side compression part 41 has the 1st compressor 50 and the 2nd compressor 51, and the two compressors 50 and 51 are connected in parallel.

The first compressor 50 and the second compressor 51 are compressors having the same format and the same output.
In the present embodiment, scroll-type hermetic compressors 50 and 51 are employed as the compressors 50 and 51. Here, the hermetic compressor is one in which motors 53 and 53 ′ and pressurizing devices 55 and 55 ′ are built in the pressure vessels 52 and 52 ′.
In the hermetic compressors 50 and 51, refrigerant return ports 60 and 60 'are provided in the pressure vessels 52 and 52'. The refrigerant return ports 60 and 60 ′ are on the upper side of the pressure vessels 52 and 52 ′.
The pressure vessels 52 and 52 ′ are provided with refrigerant discharge ports 67 and 67 ′. The refrigerant discharge ports 67 and 67 ′ communicate with discharge ports (not shown) of pressurization devices (scroll type compressors) 55 and 55 ′ arranged inside.

Furthermore, oil inlets 68 and 68 'are provided in the pressure vessels 52 and 52' of the hermetic compressors 50 and 51, respectively. The oil inlets 68 and 68 ′ are on the lower side of the pressure vessels 52 and 52 ′.
In the hermetic compressors 50 and 51, oil is stored in the pressure vessels 52 and 52 '.
In the hermetic compressors 50 and 51, the refrigerant vaporized by the low temperature side evaporator 16 returns into the pressure vessels 52 and 52 ′ from the refrigerant return ports 60 and 60 ′ provided on the upper side. The oil carried together with the refrigerant remains at the bottom of the pressure vessels 52 and 52 ', and only the vaporized refrigerant is introduced into the pressurization devices 55 and 55', pressurized, and discharged to the outside.

  The oil inlets 68 and 68 'are originally provided for maintenance, and are opened when the oil in the pressure vessels 52 and 52' is replaced.

In the present embodiment, the oil inlets 68 and 68 ′ are used for special purposes, and the oil inlets 68 and 68 ′ of the hermetic compressors 50 and 51 are connected to each other by a conduit 70.
Therefore, in this embodiment, the flow path that passes through the first compressor 50 and the flow path that passes through the second compressor 51 have the same pressure. Further, the oil level in the first compressor 50 and the oil level in the second compressor 51 are equal.
The low temperature side oil separator 42 and the pressure vessels 52, 52 ′ are connected by an oil return pipe 63. Specifically, an oil return pipe 63 is connected to a conduit 70 connecting the pressure vessels 52 and 52 ′, and the pressure vessels 52 and 52 ′ are connected to the low temperature side oil separator 42 via the conduit 70 and the oil return pipe 63. ing.

Next, operations unique to the environmental test apparatus 1 of the present embodiment will be described.
In the environmental test apparatus 1 of the present embodiment, the above-described cooling device 15 is operated to create a low-temperature environment, and a pre-cooling operation and a low-temperature exposure operation are performed. As the operation mode of the cooling device 15, two compressors 50, There are a full operation mode in which 51 is used to contribute to temperature control, and an energy saving operation mode in which only one compressor 50, 51 is used and the other compressor 50, 51 is stopped. In the present embodiment, in the full operation mode, the two compressors 50 and 51 are always operated in principle. When the auxiliary heater 23 is cooled excessively, the auxiliary heater 23 is energized and the temperature is compensated by the heat generated by the auxiliary heater 23.
In the energy saving operation mode, only one of the two compressors 50 and 51 is always operated. When the auxiliary heater 23 is cooled excessively, the auxiliary heater 23 is energized and the temperature is compensated by the heat generated by the auxiliary heater 23.

Further, in the present embodiment, when both the primary side cooling circuit 30 and the secondary side cooling circuit 31 are newly started from the state where both are stopped, and when the operation is directly started in the full operation mode from this state. In this case, a time difference is given to the activation of the two compressors 50 and 51 of the secondary side cooling circuit 31.
That is, when both the compressors 50 and 51 of the cooling device 15 are started, one compressor (in this embodiment, the second compressor 51) is used as the other compressor (in this embodiment, the first compression). The machine starts up slightly later than the machine 50). That is, the compressors 50 and 51 connected in parallel are sequentially activated with a time interval.

  And in the environmental test apparatus 1 of this embodiment, a full operation mode and an energy-saving operation mode are switched according to conditions. When one of the compressors 50 and 51 is used for a long time, the compressors 50 and 51 used in the energy saving operation mode are changed. That is, when the first compressor 50 is used as the main compressor in the energy saving operation mode and this is used for a long time, the main compressor is replaced, and the second compressor 51 is replaced by the main compressor instead of the first compressor 50. It is programmed in the control device 72 so as to be changed to a machine. That is, in the embodiment, the control device 72 performs a main compressor changing function.

Under which conditions the full operation mode is set and under which conditions the energy saving operation mode is changed depends on the set temperature (target temperature) of the low temperature exposure operation.
Hereinafter, the case where the set temperature of the low temperature exposure operation is a medium low temperature will be described as a typical example. For example, when the set temperature of the low temperature exposure operation is in the range of minus 55 degrees Celsius or more and less than minus 45 degrees Celsius, the operation mode shown in FIG.
That is, when the low-temperature exposure operation is performed when the set temperature (target temperature) of the low-temperature exposure operation is in the range of minus 55 degrees Celsius or more and less than minus 45 degrees Celsius, the temperature in the test chamber 2 becomes the set temperature. Until then, the cooling device 15 is operated in the full operation mode. After the temperature in the test chamber 2 reaches the set temperature, more precisely, after a short time has elapsed since the temperature in the test chamber 2 reaches the set temperature, the operation mode of the cooling device 15 is changed to the energy saving operation mode. Switch.

Hereinafter, description will be made with reference to the time chart of FIG. Immediately before the low temperature exposure operation is started, the high temperature exposure operation is performed, and therefore the temperature in the test chamber 2 is high as shown in the time chart of FIG.
When the low temperature exposure operation is started, the air in the test chamber 2 is replaced with the precooled low temperature air, so the temperature in the test chamber 2 rapidly decreases.
In the present embodiment, the operation mode at this time is the full operation mode, and the two compressors 50 and 51 are always operated. That is, immediately after the low temperature exposure operation is started, the air in the test chamber 2 is naturally high, so that the two compressors 50 and 51 are in a driving state. In addition, before the low temperature exposure operation is started, the pre-cooling operation is performed, and the two compressors 50 and 51 are already activated, so the two compressors 50 and 51 are driven. It will shift to low temperature exposure operation in the state.
And even if the temperature in the test chamber 2 falls and reaches the set temperature, the two compressors 50 and 51 are continuously operated, and the auxiliary heater 23 is turned on and off. If this state is maintained for a short time, the operation mode is switched to the energy saving operation mode.
That is, even if the temperature in the test chamber 2 rises, the second compressor 51 is not driven, and the temperature in the test chamber 2 is adjusted only by the first compressor 50. In the energy saving operation mode, only the first compressor 50 is always operated. The auxiliary heater 23 is controlled to be turned on / off.
When the operation mode is switched, the relationship between the detected temperature of the test chamber temperature detection sensor 6 and the target temperature of the refrigerant evaporation temperature (refrigerant target temperature) is switched as shown in FIG.

  Further, in this embodiment, the operation time of the first compressor 50 that is mainly operated is integrated, and when this time exceeds a certain time, the main compressor is replaced. That is, the second compressor 51 functions as a main compressor, and the second compressor 51 is always operated in the energy saving operation mode. The auxiliary heater 23 is controlled to be turned on / off.

The control for switching between the compressors 50 and 51 is as shown in the flowchart of FIG.
That is, when it is confirmed that the thermal shock test is being performed (step 1), the process proceeds to step 2, where the memory is checked and the conversion flag indicating whether or not the main compressor is to be replaced is on. Check for no.
If the conversion flag is not on, it is confirmed whether the current main compressor is the first compressor 50 or the second compressor 51.
For example, if it is the first compressor 50 that currently functions as the main compressor, the usage time of the first compressor 50 is accumulated in step 4. In the present embodiment, since the program of the flowchart of FIG. 5 is executed regardless of the operation mode, the time of operation in the full operation mode is also subject to integration.
In step 5, it is confirmed whether or not the accumulated usage time of the first compressor 50 exceeds 1000 hours.
If the accumulated usage time of the first compressor 50 exceeds 1000 hours, the process proceeds to step 6 where a conversion flag is set (turned on).
If it is determined in step 5 that the accumulated usage time has not exceeded 1000 hours, the process returns to step 1 to repeat this series of operations.

On the other hand, if it is determined in step 1 that the thermal shock test has not been performed, the process proceeds to step 7 to check the conversion flag. The case where the thermal shock test is not performed refers to the case where the high temperature exposure operation and the low temperature exposure operation are performed a predetermined number of times.
Here, as a result of checking the memory, if the conversion flag is ON, the process proceeds to step 8 and the main compressor is changed to the second compressor 51. That is, if the first compressor 50 has already been operated for 1000 hours or more, the fact is confirmed in step 5, and the conversion flag is turned on in step 6, the main compressor is changed to the second compressor 51. change.
Then, the conversion flag is turned off (step 9), and the accumulated operation time of the first compressor 50 is reset (step 10). Thereafter, in step 3 described above, the second compressor 51 is recognized as the main compressor, and the operation time of the second compressor 51 is integrated.

Therefore, after that, as shown in FIG. 10, the second compressor 51 functions as a main compressor.
That is, as shown in FIG. 10, when the temperature in the test chamber 2 decreases and reaches the set temperature, the operation mode is switched to the energy saving operation mode, but after that, the first compressor 50 does not contribute to the temperature control.
That is, even if the temperature in the test chamber 2 rises, the first compressor 50 does not start, and the temperature in the test chamber 2 is adjusted only by the second compressor 51.
When the operation mode is switched, the relationship between the detected temperature of the test chamber temperature detection sensor 6 and the target temperature of the refrigerant evaporation temperature is switched as shown in FIG.

  When the operation time of the second compressor 51 exceeds 1000 hours, the main compressor is changed again, and the first compressor 50 is mainly used.

  On the other hand, if it is confirmed in step 7 that the conversion flag is not turned ON, the process returns to step 1 and the previous operation is repeated.

  In the present embodiment, since the main compressor is changed while the thermal shock test is not performed, the main compressor can be changed without affecting the temperature change in the test chamber 2.

The operation mode when the set temperature for the low temperature exposure operation is an intermediate low temperature has been described above, but the case where the set temperature for the low temperature exposure operation is other than the above will also be described.
When the set temperature of the low temperature exposure operation is higher than the predetermined high temperature side reference temperature, it is as shown in FIG. 11 and is always operated in the energy saving operation mode.
That is, when the set temperature for the low temperature exposure operation is relatively high, the required cooling heat is small, so that the main compressors 50 and 51 are always operated in the energy saving operation mode.
Even in this case, the control of the flowchart shown in FIG. 5 functions effectively, and the operation time of the main compressors 50 and 51 is integrated. When this time exceeds a certain time, the main compressors 50 and 51 change. .

On the other hand, when the set temperature of the low temperature exposure operation is lower than the predetermined low temperature side reference temperature, the operation is always performed in the full operation mode as shown in FIG.
That is, when the set temperature of the low temperature exposure operation is low, a large amount of necessary cooling heat is required and cannot be covered by the main compressors 50 and 51 alone. Therefore, when the set temperature of the low temperature exposure operation is low, the temperature control is performed using all the main compressors 50 and 51.
Even in this case, the control of the flowchart shown in FIG. 5 functions effectively, and the operation time of the main compressors 50 and 51 is integrated. When this time exceeds a certain time, the main compressors 50 and 51 change.
Table 1 summarizes the relationship between the contribution of the two compressors 50 and 51 in the low temperature exposure operation and the set temperature of the low temperature exposure operation.

In addition, during the pre-cooling operation, there are cases where the operation is performed in the full operation mode and the operation is performed in the energy saving operation mode.
Also in this case, the operation mode is determined by the set temperature of the precooling operation. When the set temperature of the precooling operation is low, the operation is performed in the full operation mode as shown in FIG. That is, when the set temperature is lower than a predetermined low temperature side reference temperature, the operation in the full operation mode is performed even after the environment of the precooling chamber 3 reaches the low temperature environment of the target temperature. The “low temperature side reference temperature” in the pre-cooling operation may be different from the “low temperature side reference temperature” in the low temperature exposure operation described above.
When the set temperature for the precooling operation is high, the operation is performed in the energy saving operation mode as shown in FIG. That is, when the set temperature is higher than a predetermined high temperature side reference temperature, the operation in the energy saving operation mode is performed even when the environment in the precooling chamber 3 reaches the low temperature environment of the set temperature. Even in this case, the control of the flowchart shown in FIG. 5 functions effectively, and the operation time of the main compressors 50 and 51 is integrated. When this time exceeds a certain time, the main compressors 50 and 51 change. The “high temperature side reference temperature” in the pre-cooling operation may be different from the “high temperature side reference temperature” in the low temperature exposure operation described above, or may be the same.
Table 2 summarizes the relationship between the contributions of the two compressors 50 and 51 and the set temperature of the precooling operation in the precooling operation.

In the time chart shown in FIG. 6 described above, the entire period of the pre-cooling operation is the full operation mode, and the low temperature exposure operation is an operation pattern in which the first is the full operation mode and then is changed to the energy saving operation mode. Of course, the operation pattern is not limited to this.
As another operation pattern, there is an operation pattern in which the first half of the pre-cooling operation is the full operation mode, the remaining second half is the energy saving operation mode, the full operation mode is set before the low temperature exposure operation starts, and then the energy saving operation mode is changed. .
Further, the first half of the pre-cooling operation is the full operation mode, the remaining second half is the energy saving operation mode, the full operation mode is entered before the start of the low temperature exposure operation, and the full operation mode may be maintained as it is.
Further, the entire period of the pre-cooling operation is the energy saving operation mode, and the low temperature exposure operation has an operation pattern in which the first is the full operation mode and then the energy saving operation mode is changed thereafter.
Further, the entire period of the pre-cooling operation is the energy saving operation mode, and the full operation mode may be maintained as it is before the start of the low temperature exposure operation.
Further, the entire period of the pre-cooling operation is the energy saving operation mode, and the entire period of the low temperature exposure operation is also the energy saving operation mode.
Further, the entire period of the precooling operation is the full operation mode, and the entire period of the low temperature exposure operation may be the full operation mode.

As described above, in the full operation mode, the two compressors 50 and 51 are always operated. However, when the two compressors 50 and 51 are started, as shown in FIG. The activation of the compressor 51 is slightly delayed with respect to the first compressor 50. That is, a time difference is provided for the activation of both. Although the timing of delay may be set by a timer, it is recommended to start the second compressor 51 after the primary side cooling circuit 30 is stabilized.
For example, it is desirable to start the second compressor 51 when the detected temperature of the temperature sensor 44 provided in the primary side cooling circuit 30 is stabilized or when a certain low temperature is detected.
Of course, the first compressor 51 may be started after the second compressor 5.

Moreover, in this embodiment, since the target temperature (refrigerant target temperature) of the refrigerant | coolant evaporation temperature is changed according to the measured temperature in the test chamber 2 as mentioned above, this point is demonstrated.
In the present embodiment, the relationship between the detected temperature of the test chamber temperature detection sensor 6 and the target temperature of the refrigerant evaporation temperature (refrigerant target temperature) is as shown in the graph of FIG. 9 and is stored in the control device 72 in advance. Yes. In the present embodiment, the relationship between the detected temperature of the test chamber temperature detection sensor 6 and the refrigerant target temperature is different between the full operation mode and the energy saving operation mode.
That is, in both the full operation mode and the energy saving operation mode, the target temperature of the refrigerant evaporation temperature has an upper limit, but the upper limit (Y axis) in the energy saving operation mode is higher than the upper limit in the full operation mode. Also, the detected temperature (X axis) of the test chamber temperature detection sensor 6 when reaching the upper limit is higher in the energy saving operation mode.

This is because in the full operation mode, the amount of refrigerant supplied from the low temperature side compression unit 41 to the low temperature side expansion means 45 is large. This is because if the degree is increased, the low-temperature side evaporator 16 may not be able to evaporate the refrigerant.
That is, when the target temperature of the refrigerant evaporating temperature is raised, the opening degree of the low temperature side expansion means 45 increases, but by doing so, a large amount of refrigerant passes through the low temperature side expansion means 45. Therefore, a larger amount of refrigerant is supplied to the low temperature side evaporator 16, and there is a concern that the refrigerant cannot be evaporated and liquid return occurs. Therefore, in the full operation mode, the upper limit of the target temperature of the refrigerant evaporation temperature is lowered. Further, in the full operation mode, the refrigerant target temperature is designed to reach a peak state while the detection temperature (X axis) of the test chamber temperature detection sensor 6 is low.

  In the embodiment described above, the test chamber 2 in which the DUT is installed, the pre-cooling chamber 3 for storing low-temperature air, and the pre-heating chamber 5 for storing high-temperature air are taken as an example. It may have a high temperature chamber 71 and a low temperature chamber 73 as in the environmental test apparatus 80 shown in FIGS. 15 and 16, and the device under test 75 may go back and forth between them.

In the embodiment described above, two compressors are provided in the secondary side cooling circuit. However, the compressor may have three or more compressors.
In the embodiment described above, the compressor that contributes to the adjustment of the environmental temperature in the energy saving operation mode is changed according to the total operation time that is the sum of the state that is operating in the full operation mode and the state that is operating in the energy saving mode. However, the compressor that contributes to the adjustment of the environmental temperature in the energy saving operation mode may be changed based on the integrated value only in the state of operation in the energy saving mode.

In the embodiment described above, both the compressors 50 and 51 are always operated in the full operation mode, and only one of the compressors 50 and 51 is always operated in the energy saving operation mode, and the temperature is excessively lowered. In this case, the auxiliary heater 23 was energized and adjusted so that the temperature matched the target temperature.
Instead of this, the number of revolutions of the motor that drives the compressors 50 and 51 may be controlled so that the temperature of the test chamber 2 or the like becomes the target temperature.
For example, the motor that drives the compressors 50 and 51 can be inverter-controlled to change the rotation speed.
When operating in the full operation mode, the two compressors 50 and 51 are always operated, and the motors of the compressors 50 and 51 are synchronously inverter-controlled to match the temperature of the test chamber 2 and the like with the target temperature. Let

Alternatively, the two compressors 50 and 51 may be controlled on and off. The time chart when this configuration is adopted is as shown in FIGS. 17 and 18. In the full operation mode, the two compressors 50 and 51 are simultaneously turned on when the cooling device 15 is turned on. . Further, at the timing when the cooling device 15 is turned off, the two compressors 50 and 51 are turned off simultaneously.
In the energy saving operation mode, only one of the compressors 50 and 51 is turned on and off, and the other is kept stopped.
Further, the compressors 50 and 51 in the full operation mode may be started simultaneously.

(Reference invention)
As a reference invention, it is conceivable to apply the main configuration of the present invention to an environmental test apparatus 100 having a one-way refrigeration circuit.
The piping system of the environmental test apparatus 100 is as shown in FIG.
The piping system of the environmental test apparatus 100 does not have a cascade capacitor, and a condenser 101 is provided instead.
The environmental test apparatus 100 is an environmental test apparatus that has a cooling device and can create a low-temperature environment of a target temperature in a predetermined space. The cooling device includes a compression unit 41, a condenser 101, and expansion means 45. And the evaporator 16 are sequentially piped in an annular manner to circulate the phase-change refrigerant therein, and the compression section 41 of the cooling circuit has two or more compressors 50 and 51, which are It is connected in parallel, all the compressors 50 and 51 are operated, and all the compressors 50 and 51 are operated in a full operation mode that contributes to the adjustment of the environmental temperature. Only 51 operates, only some of the compressors 50 and 51 contribute to the adjustment of the environmental temperature, and the other compressors 50 and 51 can be operated in an energy saving operation mode that does not contribute to the adjustment of the environmental temperature. To do.
The flowchart and time chart of the operation of the environmental test apparatus 100 are the same as those in the above-described embodiment.

1 Environmental test equipment 2 Test room 3 Pre-cooling room (pre-cooling space)
5 Preheating chamber 6 Test chamber temperature detection sensor 13 Precooling chamber temperature detection sensor 15 Cooling device 16 Low temperature side evaporator 25 DUT 30 Primary side cooling circuit 31 Secondary side cooling circuit 32 High temperature side compressor 33 High temperature side oil separator 35 High temperature Side condensing part 36 High temperature side expansion means 37 Cascade capacitor 38 Primary side flow path 40 High temperature side accumulator 41 Low temperature side compression part 42 Low temperature side oil separator 43 Secondary side flow path 44 Temperature sensor 45 Low temperature side expansion means 46 Low temperature side accumulator 50 1 compressor 51 2nd compressor 52, 52 ′ pressure vessel 55, 55 ′ pressurizing device 58 refrigerant temperature detection sensor 60, 60 ′ refrigerant return port 67, 67 ′ refrigerant discharge port 68, 68 ′ oil introduction port 70 conduit 71 High greenhouse 73 Low greenhouse 75 DUT 80 Environmental test equipment

Claims (8)

An environmental test apparatus having a cooling device and capable of creating a low temperature environment of a target temperature in a predetermined space, wherein the cooling device includes a primary cooling circuit and a secondary cooling circuit. The primary side cooling circuit has a high temperature side compression unit, a high temperature side condensing unit, a high temperature side expansion means, and a primary side of the cascade condenser that is sequentially arranged in an annular shape, and circulates a phase change refrigerant therein. The secondary side cooling circuit is an environment in which a low temperature side compression unit, a secondary side of a cascade condenser, a low temperature side expansion means, and a low temperature side evaporator are sequentially arranged in an annular shape, and a phase-change refrigerant is circulated therein. In the test equipment,
The low temperature side compression section of the secondary side cooling circuit has two or more compressors connected in parallel, and all the compressors are operated and all the compressors are at ambient temperature. Operation in the full operation mode that contributes to the adjustment of energy consumption, energy saving operation in which only some of the compressors operate and only some of the compressors contribute to the adjustment of the environmental temperature, and other compressors do not contribute to the adjustment of the environmental temperature Ri is possible der operation by mode,
The low temperature side expansion means adjusts the opening so that the temperature of the refrigerant in the vicinity or downstream of the low temperature side expansion means becomes a predetermined refrigerant set temperature, and the actual temperature of the predetermined space The relationship with the refrigerant set temperature is associated with a predetermined relationship in advance,
An environmental test apparatus characterized in that the relationship is changed between a full operation mode and an energy saving operation mode . The environmental test equipment performs a thermal shock test, and can perform a low-temperature exposure operation in which a high-temperature or medium-temperature test object is exposed to a low-temperature environment of a target temperature. Is operated in the full operation mode until the test environment in which the is placed reaches the low temperature environment of the target temperature or a temperature in the vicinity thereof, and after the test environment reaches the target temperature or in the vicinity of the temperature, the energy saving operation mode is used. The environmental test apparatus according to claim 1 , wherein the environmental test apparatus is operated. The environmental test equipment performs a thermal shock test, and it is possible to perform a low-temperature exposure operation in which a high-temperature or medium-temperature test object is exposed to a low-temperature environment of a target temperature, until a low-temperature exposure operation is performed. During this period, a pre-cooling space for storing low-temperature air is provided, and until the low-temperature exposure operation is performed, the pre-cooling operation for cooling the pre-cooling space and maintaining the pre-cooling space at the pre-cooling target temperature is performed.
It is possible to set the precooling target temperature of the precooling space during the precooling operation. When the precooling target temperature is low, the precooling operation is performed in the full operation mode, and when the precooling target temperature is high, the energy saving operation mode is set. The environmental test apparatus according to claim 1 or 2 , wherein a pre-cooling operation is performed. The environmental test equipment performs a thermal shock test, and can perform a low-temperature exposure operation in which a high-temperature or medium-temperature test object is exposed to a low-temperature environment of a target temperature. It is possible to set a target temperature of the environment in which the DUT is placed, and when the target temperature is higher than a predetermined high temperature side reference temperature, the environment in the test space reaches a low temperature environment of the target temperature. Even if the target temperature is lower than a predetermined low temperature side reference temperature, the environment in which the DUT is placed has reached the low temperature environment of the target temperature. 4. The environmental test apparatus according to claim 1, wherein the operation is performed in a full operation mode. When the primary side cooling circuit and the secondary side cooling circuit are started from a state where both the primary side cooling circuit and the secondary side cooling circuit are stopped, and the operation mode at that time is the full operation mode, in parallel, The environmental test apparatus according to claim 1, wherein the connected compressors are sequentially activated at intervals of time. All the compressors in the low temperature side compression unit are hermetic compressors in which a motor and a pressurizing device are built in a hermetic container, and the hermetic containers of all the compressors in the low temperature side compression unit are connected by a conduit. The environmental test apparatus according to claim 1, wherein The operating time integrating means integrates the operating time of the compressor on the side that contributes to the adjustment of the environmental temperature even in the energy saving operation mode. The environmental test according to any one of claims 1 to 6 , further comprising a main compressor changing function for changing a compressor that contributes to the adjustment of the environmental temperature in the energy saving operation mode when a predetermined time is reached. apparatus. The relationship between the actual temperature of the predetermined space and the refrigerant set temperature is a relationship in which the refrigerant set temperature increases when the actual temperature of the predetermined space increases in both the full operation mode and the energy saving operation mode. The upper limit in the target temperature of the refrigerant evaporation temperature in both the energy saving operation mode and the energy saving operation mode, and the upper limit in the energy saving operation mode is higher than the upper limit in the full operation mode. The environmental test apparatus described.

Images