JPH0316649A - Environment tester - Google Patents

Abstract

PURPOSE:To easily create a wide range of temps. by connecting the expansion mechanism in the cooling unit of the final stage to a refrigerant outlet side of one flow passage of an intermediate heat exchanger in the cooling unit of the final stage and constituting the expansion mechanism in such a manner that the opening degree thereof can be freely adjusted. CONSTITUTION:An increases in the low-pressure side of the intermediate heat exchanger of the cooling unit is triggered by an increase in an evaporating pressure when the opening degree of the expansion mechanism 14 of the final stage is increased. The ratio of the condensing and liquefying of the high boiling refrigerant in a solvent mixture is lowered by this increase and the refrigerant flowing to an evaporator 9 becomes the refrigerant mixture contg. the high boiling refrigerant at a high ratio. A relatively high temp. is thus obtd. The temps. of a wide range from an ultra low temp. to a relatively high temp. is easily created by constituting the expansion mechanism 14 of the final stage in such a manner that the opening degree thereof can be freely adjusted.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention provides a method for storing a sample in a test chamber. This relates to an environmental test device that alternately supplies high-temperature air and low-temperature air to the test chamber and applies a thermal shock to the sample to perform a durability test.In particular, it uses a refrigeration cycle as an ultra-low temperature generator to generate a wide range of temperatures. The present invention relates to an environmental test device suitable for.

[Conventional technology]

Conventionally, in environmental test equipment that uses a refrigeration cycle as an ultra-low temperature generator, it is necessary to generate a wide range of temperatures, remove frost adhering to the air side surface of the evaporator, and also perform refrigeration extraction, which is discharged from the compressor together with the refrigerant. However, in order to prevent the expansion mechanism, which has a narrow flow path, from clogging in the refrigeration cycle, means are provided for increasing the temperature of the evaporator section and the expansion mechanism section.

Regarding this type of environmental test equipment, for example,
- A technique described in Japanese Patent No. 89429 is known.

That is, in the environmental test device described in the above-mentioned publication, a multi-component refrigeration cycle in which two or more refrigeration cycles are combined in a cascade is used as the ultra-low temperature generator.
In order to raise the temperature of the evaporator part, the discharge gas of the compressor in the high temperature side cycle is evaporated 9! A structure is adopted in which the heat flows into a heat exchanger installed in parallel with the heat exchanger. Additionally, a method of heating with an electric heater is also generally used.

[Problem to be solved by the invention]

The above-mentioned conventional technology is a technology for increasing the temperature of the evaporator portion of the refrigeration cycle, but no consideration has been given to obtaining a wide range of temperatures from extremely low temperatures to relatively high temperatures. For this reason, there was a problem in that it was difficult to obtain a wide range of low temperature conditions, from extremely low temperatures to relatively high temperatures, with a single environmental test device. Furthermore, no consideration has been given to improving the defrosting speed when removing frost adhering to the surface of the evaporator, for example. For this reason, there is a problem in that the defrosting operation becomes unnecessary, considering the intended purpose of the environmental testing apparatus used for testing the durability against thermal shock of electronic parts and the like. To improve this point, appropriate capacity l)
There is also a method of using an electric heater, but this increases operating costs and is not a very desirable method from the point of view of energy conservation. The first aspect of the present invention
The purpose of is to use a refrigeration cycle as an ultra-low temperature generator,
The object of the present invention is to provide an environmental test device that can easily generate a wide range of temperatures from extremely low temperatures to relatively high temperatures in the evaporator section. A second object of the present invention is to provide a ring k1t wiping device capable of easily removing frost adhering to equipment such as an evaporator while operating at extremely low temperatures. Furthermore, a third object of the present invention is to provide an environmental test device that can prevent frost formation on the evaporator, etc., and eliminate the need for N removal operation. [Means for Solving the Problems] The first object is to provide a test chamber, an ultra-low temperature generating device and a heating device for creating an environment in the test chamber, the ultra-low temperature generating device being constituted by a refrigeration cycle, and the refrigeration cycle of,
A single compressor that compresses a mixture of refrigerants with different boiling points, a condenser that condenses the compressed refrigerant, a cooling unit installed in multiple stages, and a unit connected to the high pressure side of the final stage cooling unit. A final stage expansion mechanism, an evaporator connected to the expansion mechanism and generating ultra-low temperature, and piping for returning refrigerant from the evaporator to the compressor via the cooling units of each stage. The cooling unit of each stage is divided into a gas-liquid separator that separates the condensed medium into gas refrigerant and liquid refrigerant, and a low-pressure separator that guides the separated gas refrigerant into one flow path and flows through the other flow path. An intermediate heat exchanger that cools with a low-temperature refrigerant, an expansion mechanism that reduces the pressure of the separated liquid refrigerant, and piping that guides the reduced pressure low-pressure low-temperature refrigerant to the other flow path of the intermediate heat exchanger, The final stage expansion mechanism is connected to the refrigerant outlet side of one flow path in the intermediate heat exchanger of the final stage cooling unit, and at least the final stage expansion mechanism is an expansion mechanism whose opening degree can be adjusted. This is achieved by The second purpose is to connect the discharge side of the compressor and the refrigerant inlet side of the evaporator in the ultra-low temperature generator through hot gas bypass piping, and to install an on-off valve and an adjustable valve in the hot gas bypass piping. Either an on-off valve or an adjustable opening valve is installed in the piping connecting the other flow path of the intermediate heat exchanger of the final stage cooling unit and the refrigerant outlet side of the evaporator, and this piping This can be achieved by providing another pipe in parallel with the pipe and providing an expansion mechanism in the other pipe. The second purpose is to reinstall a heating heat exchanger on either the air inlet side or the air outlet side of the evaporator in the ultra-low temperature generator, and to connect the heating heat exchanger to the discharge side of the compressor and the heating heat exchanger. Connect the refrigerant inlet side with hot gas bypass piping,
This hot gas bypass piping is provided with either an on-off valve or a valve whose opening degree can be adjusted, and the heating This can also be achieved by connecting the refrigerant outlet side of the heat exchanger via a bypass pipe and providing an expansion mechanism in the bypass pipe.

The second purpose is to make the refrigerant outlet side of the heating heat exchanger
This can also be achieved by connecting, via another pipe, to the pipe connecting one flow path of the intermediate heat exchanger of the final stage cooling unit and the refrigerant inlet side of the final stage expansion mechanism. The second purpose is to make the refrigerant outlet side of the heating heat exchanger
This can also be achieved by connecting via piping to the refrigerant inlet side of the expansion mechanism of at least one cooling unit of the cooling units provided in multiple stages.

The second objective is achieved by providing the hot gas bypass piping with a heating section that heats the expansion mechanism of the cooling unit in each stage and its vicinity by the refrigerant flowing through the hot gas bypass piping. .

The second purpose is to provide a test room, a high temperature room, and a low temperature room, install a heating device in the high temperature room, connect one of the ultralow temperature generators to the low temperature room, and connect the test room with a heating device. By connecting the high temperature chamber, the test chamber, and the low temperature chamber with air channels, and also connecting the high temperature chamber and the low temperature chamber with air channels, and providing a damper in each air channel, even better results can be achieved. be decapitated.

The third object is achieved by using an inert gas having a boiling point lower than the temperature generated by the ultra-low temperature generator as the fluid flowing in the ultra-low temperature generator. [Function] According to the present invention, cold heat is generated by cooling/heating into the sample chamber of an environmental test apparatus that includes a sample chamber, an ultralow temperature generator, and a heating device. # Set up samples such as electronic components to be subjected to shock and durability tests. Next, the ultra-low temperature generator and the heating device are started, and low-temperature air and high-temperature air are alternately supplied to the test chamber from the ultra-low temperature generator and the heating device, thereby creating an alternate cooling environment and a heating environment in the test chamber. , conduct a durability test by applying a thermal shock to the sample by cooling/heating. The cooling environment is created by operating a refrigeration cycle, which is an ultra-low temperature generator, as follows. First, as a refrigerant, for example, R12, R13,
A mixed refrigerant containing R14 is used.

Then, when the refrigeration cycle is started, the refrigerant is compressed by the compressor, condensed by the condenser, liquefied, and guided to the first stage of the cooling units installed in multiple stages.

The refrigerant introduced into the first-stage cooling unit is separated into gas refrigerant and liquid refrigerant in a gas-liquid separator. The separated gas refrigerant is led to one flow path of the intermediate heat exchanger of the first stage cooling unit, and is cooled by exchanging heat with the low-pressure, low-temperature refrigerant flowing through the other flow path of the intermediate heat exchanger. It is guided to the gas-liquid separator of the second-stage cooling unit. The liquid refrigerant separated by the gas-liquid separator of the first-stage cooling unit is guided to the expansion mechanism of the same first-stage cooling unit, is depressurized by this expansion mechanism, becomes a low-pressure, low-temperature refrigerant, and is transferred to the middle of the same first-stage cooling unit. It is guided to the other flow path of the heat exchanger. In the second-stage and subsequent cooling units, the refrigerant passes through the same process as in the first-stage cooling unit.

Next, the refrigerant that has been cooled and liquefied in the intermediate heat exchanger of the final stage cooling unit is led to the final stage expansion mechanism, where the pressure is reduced and flows into the evaporator, which is the most liquefied refrigerant in this refrigeration cycle. Generates a low temperature. The refrigerant that has exited the evaporator passes through the intermediate heat exchanger of the final stage cooling unit, then the intermediate heat exchanger of the lower stage cooling unit, passes through the intermediate heat exchanger of the first stage cooling unit, and is absorbed by the compressor. Ru.

In this refrigeration cycle, at least the final stage expansion mechanism,
In other words, the expansion mechanism on the refrigerant inlet side of the evaporator is an expansion mechanism whose opening degree can be adjusted. As a result, if the opening degree of this final stage expansion mechanism is increased, for example, the temperature on the low pressure side of the intermediate heat exchanger of the cooling unit, which is triggered by an increase in evaporation pressure, will rise, so the The condensation rate of the high boiling point refrigerant is reduced, and the refrigerant flowing into the evaporator becomes a mixed refrigerant with a high proportion of high boiling point refrigerant, resulting in a relatively high temperature and low temperature state. Therefore, in the present invention, by adjusting the opening degree of the final stage expansion mechanism, it is possible to easily create a wide range of temperatures from extremely low temperatures to relatively high temperatures.

Furthermore, in the present invention, the discharge side of the compressor in the ultra-low temperature generator is connected to the refrigerant inlet side of the evaporator by a hot gas bypass pipe, and the hot gas pass pipe is provided with an on-off valve or a valve whose opening degree can be adjusted. , Since a mixed refrigerant with a high boiling point can be supplied to the evaporator at a high temperature through the hot gas bypass piping, a wider range of temperatures can be obtained. In addition, in this invention, the temperature of the mixed refrigerant discharged from the compressor is higher than room temperature, which is a high temperature level even in the refrigeration cycle, and frost adhering to the evaporator can be removed by operating at an extremely low temperature. Furthermore, in the present invention, a heating heat exchanger is installed on the air inlet side or the air outlet side of the evaporator in the ultralow temperature generator, and the hot gas bypass is established between the discharge side of the compressor and the refrigerant inlet side of the heating heat exchanger. Connected by piping, this hot gas bypass piping is equipped with an on-off valve or a valve with adjustable opening.
Since the air is heated by the heating heat exchanger, a wide range of temperatures can be obtained and frost can be prevented from adhering to the evaporator, and there is no need to install an on-off valve in the main circuit. Since the pressure loss caused by the on-off valve can be eliminated, it is possible to improve the efficiency of the refrigeration cycle.

Furthermore, in the present invention, the refrigerant outlet side of the heating heat exchanger is connected to a pipe connecting one flow path of the intermediate heat exchanger of the final stage cooling unit and the refrigerant inlet side of the final stage expansion mechanism. , the air is heated in a heating heat exchanger using a hot gas refrigerant with a large proportion of high boiling point refrigerant discharged from the compressor, and then the refrigerant flows out from the heating heat exchanger. The refrigerant is combined with the refrigerant flowing out from the high pressure side of the intermediate heat exchanger of the final stage cooling unit, and then guided to the final stage expansion mechanism, where the pressure is reduced and the refrigerant flows into the evaporator. Because of this, relatively high temperatures can be obtained, and therefore a wider range of temperatures can be obtained.

Further, in the present invention, the refrigerant outlet side of the heating heat exchanger is
It is connected to the refrigerant inlet side of the expansion mechanism of at least one of the cooling units installed in multiple stages, and the expansion mechanism of the final stage, that is, the expansion mechanism on the refrigerant inlet side of the evaporator, is completely idle, and hot gas bypass is performed. By opening an on-off valve or an adjustable valve installed in the piping and allowing hot gas refrigerant to flow through the heating heat exchanger, it is possible to effectively remove frost that adheres to the evaporator during low-temperature operation. can. Furthermore, in the present invention, the hot gas bypass piping is provided with a heating section that heats the expansion mechanism of the cooling unit of each stage and its vicinity by the refrigerant flowing through the hot gas bypass piping, so that in case of expansion of the cooling unit, If the assimilation oil is clogged in the mechanism, the assimilated oil can be melted and removed using a relatively high temperature generating operation such as a defrosting operation mode.

Furthermore, in the present invention, a test room and a test room. A high-temperature chamber and a low-temperature chamber are provided, and the test chamber and the high-temperature chamber and the test chamber and the low-temperature chamber are connected by air channels, respectively, and the high-temperature chamber and the low-temperature chamber are also connected by an air channel. A damper is installed in the
By selectively opening the damper, high temperature air can be supplied from the high temperature chamber to the low temperature chamber even during testing.
Therefore, the frost that adheres to the evaporator during low-temperature operation can be removed using the high-temperature air from the high-temperature chamber side.

In addition, in the present invention, as the fluid flowing in the ultra-low temperature generator, an inert gas having a boiling point lower than the temperature generated by the ultra-low temperature generator is used, so frost formation on low-temperature parts such as the evaporator can be prevented. Defrosting operation becomes unnecessary.

〔Example〕

Embodiments of the present invention will be described below with reference to FIGS. 1 to 7.

FIG. 1 shows the first embodiment of the present invention, and is a partially sectional system diagram. This first embodiment includes a test chamber (2), a high temperature chamber 2, and a low temperature chamber 3.

In the test chamber 1, samples such as electronic components (not shown) are installed. Further, in the test chamber I, two air passages communicating with the outside air are formed at a distance from each other, and each air passage is provided with dampers 18a and 18b. The high temperature chamber 2 is provided with a heating device.

This heating device includes a heater 15 such as an electric heater and a blower 16 for a high temperature room.

The test chamber 1 and the high temperature chamber 2 are connected by two air channels spaced apart from each other, and each air channel is provided with dampers 18c and 18d.

An ultra-low temperature generator is connected to the cold room 3,
A blower 17 for the cold room is also provided. The test chamber 1 and the cold room 3 are spaced apart from each other.
They are connected by two air channels, and each air channel has one damper.
8e and 18f are provided.

In the present invention, a refrigeration cycle is used as the ultra-low temperature generator. In this embodiment, a unitary mixed refrigerant/refrigeration cycle is used. The unit mixed refrigerant/refrigeration cycle consists of a single compressor 4, a condenser 5, a subcooler 6, a first-stage cooling unit 1, a second-stage cooling unit ■, and a tension mechanism in the final stage. 14, an evaporator 9 installed in the cold room 3, and an expansion tank 27 are connected by piping. The first stage cooling unit i includes a gas-liquid separator 10 that is connected to the refrigerant outlet side of the supercooler 6 and separates the condensed refrigerant into a gas refrigerant and a liquid refrigerant; an intermediate heat exchanger 7 that guides a gas refrigerant into one flow path and cools it with a low-pressure low-temperature refrigerant flowing through the other flow path; It is configured to include an expansion mechanism 12 that causes the flow to flow into the other flow path of the exchanger 7. The expansion mechanism 12 uses a capillary tube in this embodiment.

The second stage cooling unit n is the first stage intermediate heat exchanger 7.
a gas-liquid separator 11 connected to the outlet side of the cooled refrigerant and separating the condensed refrigerant into gas refrigerant and liquid refrigerant;
An intermediate heat exchanger 8 guides the gas refrigerant separated in the gas-liquid separator 11 to one channel and cools it with a low-pressure low-temperature refrigerant flowing in the other channel, and the gas-liquid separator 11 separates the gas refrigerant. The expansion mechanism 13 reduces the pressure of the liquid refrigerant and causes it to flow into the other channel of the intermediate heat exchanger 8. and,
The expansion mechanism 13 also uses a capillary tube in this embodiment. At least the final stage expansion mechanism 14 is an expansion mechanism whose opening degree can be adjusted, and in this embodiment, an electric expansion valve is used. This final stage expansion mechanism 14 is connected via piping to the high pressure side of the intermediate heat exchanger 8 of the second stage cooling unit (2), that is, to the outlet side of the refrigerant cooled by this intermediate heat exchanger 8. , the liquefied refrigerant cooled in the intermediate heat exchanger 8 of the second stage cooling unit ■ is depressurized,
It is designed to lead to evaporator 9. The evaporator 9 generates the lowest temperature in the refrigeration cycle with the refrigerant flowing from the expansion mechanism 14 at the final stage, and generates low-temperature air in the cold room 3. In addition, the refrigerant outlet side of the evaporator 9 passes through piping, and the refrigerant is compressed via the intermediate heat exchanger 8 of the second-stage cooling unit ■→the intermediate heat exchanger 7 of the first-stage cooling unit I→the supercooler 6. It is connected to return to aircraft 4. The expansion tank 27 is designed to temporarily recover refrigerant when the refrigeration cycle is stopped. The environmental test apparatus of the first embodiment is operated and functions as follows.

First, a sample (not shown) such as an electronic component is installed in the test chamber 1, and a heater 15 provided in the high temperature chamber 2, a blower 16 for the high temperature chamber, and an ultra-low temperature generator connected to the low temperature chamber 3 are installed. The refrigeration cycle device and the cold room blower 17 are started, and the set of dampers 18c and 18d and the dampers 18e and 18 are activated.
F sets are opened alternately, and high-temperature air and low-temperature air are introduced into the test chamber 1 through the air flow path connecting the test chamber 1 and the high temperature chamber 2 and the air flow path connecting the test chamber 1 and the low temperature chamber 3. supply alternately,
A durability test is performed by subjecting the sample to thermal shock.

By the way, in the refrigerant cycle which is the ultra-low temperature generating device, for example, Rl2, R13, R
A mixed refrigerant containing l4 is used. Next, when the refrigeration cycle is started, the refrigerant is compressed by the compressor 4, condensed by the condenser 5, and cooled by the subcooler 6, and R12, which has the highest boiling point, is condensed and liquefied, and is sent to the first stage cooling unit I. be guided.

The refrigerant introduced to the first-stage cooling unit I is separated into gas refrigerant and liquid refrigerant by the gas-liquid separator lo of the first-stage cooling unit I. Gas-liquid separator 1 of the first stage cooling unit ■
The main components of the gas refrigerant separated at 0 are R13 and R14, and this gas refrigerant is led to one flow path of the intermediate heat exchanger 7 of the first-stage cooling unit i, and is led to the other flow path of the same intermediate heat exchanger 7. It exchanges heat with the low-pressure, low-temperature refrigerant flowing through the flow path, and is cooled to liquefy R13, which has a high boiling point, and is guided to the gas-liquid component 1ii11 of the second-stage cooling unit (2). The liquid refrigerant separated by the gas-liquid separator 1o of the first-stage cooling unit (2) is throttled by the expansion mechanism 12 of the first-stage cooling unit I, and becomes a low-pressure, low-temperature refrigerant that is used in the first-stage cooling unit! It flows into the low pressure side of the intermediate heat exchanger 7, that is, the other flow path of the intermediate heat exchanger 7. 1 liter of gas-liquid separator of the second stage cooling unit ■
The refrigerant introduced is separated into R14 gas refrigerant and R13 liquid refrigerant in this gas-liquid separator 11. The R14 gas refrigerant separated by the gas-liquid separator 11 of the second-stage cooling unit ■ is transferred to the intermediate heat exchanger 8 of the second-stage cooling unit ■.
The refrigerant is introduced into one flow path of the intermediate heat exchanger 8 and exchanges heat with the low-pressure low-temperature refrigerant flowing through the other flow path of the same intermediate heat exchanger 8. The R14 gas refrigerant is cooled, liquefied, and guided to the final stage expander 4iI14. Gas-liquid separator l1 of the second-stage cooling unit ■
The separated R13 liquid refrigerant is throttled by the expansion mechanism 13 of the 52nd-stage cooling unit I1, becomes a low-pressure, low-temperature refrigerant, and enters the other flow path of the intermediate heat exchanger 8 of the second-stage cooling unit (2). flows into.

Said final stage expansion 4e! The refrigerant introduced into the refrigeration cycle 14 is depressurized by the expansion mechanism 14, flows into the evaporator 9, and generates the lowest temperature in the refrigeration cycle. When the evaporator 9 generates a low temperature, low temperature air is generated in the cold room 3. By introducing the low-temperature air into test chamber 1, a low-temperature environment can be created in test chamber 1. According to this refrigeration cycle, when R14 having the lowest boiling point is completely separated from other refrigerants and introduced into the evaporator 9, R14 at the same pressure as the low pressure side operating pressure at that time
The temperature at which the saturation temperature occurs can be obtained. However, if R13 and Rl4 having a high boiling point are mixed into R14 supplied to the evaporator m9, the temperature obtained in the evaporator 9 will become higher even if the low pressure side pressure conditions are the same as in the above case. Therefore, the expansion mechanism 12 of the first stage cooling unit 1,
At least the final stage expansion mechanism 14 of the second stage cooling unit 13 and the final stage expansion mechanism l4.
By using an expansion mechanism with adjustable opening, such as an electric expansion valve, and changing the opening, the temperature level changes as the pressure conditions on the low pressure side change. In other words, the final stage of swelling! 1
I! For example, when the opening degree of the mechanism 14 is increased, an increase in evaporation pressure is triggered and the low pressure side temperature of the first and second stage intermediate heat exchangers 7, 8 increases. The temperature difference between the high-pressure side temperature and the driving force of 8 changes, and the R12, R
Condensation and liquefaction of l3; ¥11 go is different. In this way, the mixing ratio of refrigerant flowing into the evaporator 9 can be changed, so the evaporator Low-temperature conditions can be obtained over a relatively wide range without installing a new hot gas bypass heat exchanger in the area. Note that the cooling unit is not limited to the one installed in two stages;
Three or more stages may be installed. Furthermore, regarding the adjustment of the opening degree of the expansion mechanism, in addition to the expansion mechanism 14 at the final stage, the expansion mechanism of the cooling unit at each stage may also be capable of adjusting the opening degree.

Next, FIG. 2 shows a second embodiment of the present invention, and is a system diagram partially shown in cross section.

In this second embodiment, the discharge side of the compressor 4 and the pipe connecting the final stage expansion mechanism 14 and the refrigerant inlet side of the evaporator 9 are connected by a hot gas bypass pipe 19. The hot gas bypass pipe 19 has an on-off valve 2.
1 is provided.

In addition, the refrigerant outlet side of the evaporator 9 is connected to the refrigerant inlet side of the other flow path of the intermediate heat exchanger 1i%9 of the second stage cooling unit (2), which is the final stage cooling unit in this embodiment. An on-off valve 22 is provided in the piping. Further, a bypass pipe 20 is provided in the pipe connecting the refrigerant outlet side of the evaporator 9 and the refrigerant inlet side of the other flow path of the intermediate heat exchanger 8 of the second stage cooling unit (2). The bypass piping 20 is provided with an expansion mechanism 23 . This expansion mechanism 23 uses a capillary tube.

In this second embodiment, high boiling point R12, R
13 mixed refrigerants can be supplied at high temperatures. Therefore, a wider range of temperatures can be obtained than in the first embodiment. In addition, in this second embodiment, the temperature of the mixed refrigerant discharged from the compressor 4 is above room temperature, which is the highest in the refrigerant cycle. level. Therefore, this mixed refrigerant is transferred to the evaporator 9.
By introducing this into the evaporator 9, it is possible to remove frost adhering to the evaporator 9 during ultra-low temperature operation. In this second embodiment, instead of the on-off valves 21 and 22, a valve whose opening degree can be adjusted, such as an electric valve, may be used. Regarding other structures and functions of this second embodiment,
This is the same as the first embodiment. Next, FIG. 3 shows a third embodiment of the present invention, and is a system diagram partially cut away.

In this third embodiment, a heating heat exchanger 24 is installed on the air inlet side or the air outlet side of the evaporator 9. The refrigerant inlet side of the heating heat exchanger 24 and the discharge side of the compressor 4 are connected by a hot gas bypass pipe 19. This hot gas bypass piping 19 is provided with an on-off valve 21. In addition, the heating heat exchanger 24
The refrigerant outlet side of and the refrigerant inlet side of the other flow path of the intermediate heat exchanger 8 of the second stage cooling unit (2), which is the final stage cooling unit in this embodiment, are connected by a pipe. An expansion mechanism 23 is provided. This expansion mechanism 2
3, a capillary tube is used.

In this third embodiment, the compressor 4 is connected to the heating heat exchanger 2.
A hot gas refrigerant having the highest temperature level in the refrigeration cycle is supplied through the hot gas bypass pipe 19 of No. 4, and the air inlet side or the air outlet side of the evaporator 9 is heated by this heating heat exchanger 24. . Therefore, not only can a wide range of temperatures be obtained during normal operation of the ultra-low temperature generator, but also frost adhering to the evaporator 9 can be removed during ultra-low temperature operation.

Moreover, in the third embodiment, the on-off valve 22 and the valve whose opening degree can be adjusted, which were provided in the main circuit in the second embodiment, are not required, so that the pressure loss caused by these valves can be eliminated. This makes it possible to improve the efficiency of ultra-low temperature generators. The other configurations and functions of this third embodiment are the same as those of the second embodiment. Next, FIG. 4 shows a fourth embodiment of the present invention.
It is a system diagram with a part cut away.

In this fourth embodiment, the refrigerant outlet side of the heating heat exchanger 24 is connected to one side of the intermediate heat exchanger 8 of the second-stage cooling unit (2), which is the final-stage cooling unit of this embodiment, via piping. It is connected to a pipe connecting the flow path and the final stage expansion mechanism 14.

According to this fourth embodiment, the air is heated via the heating heat exchanger 24 with the hot gas refrigerant having a high proportion of R12 and Rl3 having high boiling points discharged from the compressor 4, and
After the refrigerant flowing out from this heating heat exchanger 24 joins with the refrigerant flowing out from the high pressure side of the intermediate heat exchanger 8 of the second stage cooling unit (2), it is depressurized in the final stage expansion mechanism 14 and evaporated. Because of the flow into the vessel 9, relatively high temperatures are obtained in the evaporator 9 and therefore a wide range of temperatures can be obtained.

Regarding other configurations and functions of this fourth embodiment,
This is the same as the third embodiment.

Furthermore, FIG. 5 shows a fifth embodiment of the present invention,
This is a partial cross-sectional diagram of the system. In this fifth embodiment, the refrigerant outlet side of the heating heat exchanger 24 is connected via piping to the refrigerant inlet side piping of the expansion mechanism 12 of the first-stage cooling unit I.

According to this fifth embodiment, the expansion mechanism 14 at the final stage is completely idle, and the on-off valve 21 provided in the hot gas bypass pipe 19 is opened to allow hot gas refrigerant to flow into the heating heat exchanger 24. As a result, frost adhering to the evaporator 1t9 can be removed during low-temperature operation.

In addition, in this fifth embodiment, the heating heat exchanger 24
The refrigerant outlet side of the expansion mechanism 1 of the second stage cooling unit ■
It may be connected to the piping on the refrigerant inlet side of No. 3, or it may be branched and connected to the piping on the refrigerant inlet side of the expansion mechanism of the cooling unit of each stage.

Further, other configurations and functions of this fifth embodiment are as follows.
, similar to the fourth embodiment.

Next, No. 6 @ shows the sixth embodiment of the present invention, and is a system diagram with a part of it in cross section.

In this sixth embodiment, a hot gas bypass pipe 19 is connected to the discharge side of the compressor 4 and the pipe connecting the final stage expansion mechanism 14 and the evaporator 9. An on-off valve 21 is provided in the . The hot gas bypass piping 19 is thermally connected to the expansion mechanisms 12.13 of each stage of the cooling units and the vicinity thereof, and the expansion mechanisms 12, 13 and the expansion mechanisms 12.13 are Heating sections 12' and 13' are provided to heat the vicinity of the refrigerant inlet and refrigerant outlet.

According to this sixth embodiment, if the expansion mechanisms 12 and 13 of the cooling units I and II of each stage become clogged with solidified oil, the expansion mechanism 14 of the final stage is closed and the hot gas bypass piping 19 is closed. When opening the on-off valve 21 provided in the
l&! The solidified oil can be melted and removed by utilizing a relatively high-temperature operation such as during rotation mode.

In addition, since the final stage expansion mechanism 14 is fully opened during the defrosting operation mode, the heat of the hot gas refrigerant supplied to the evaporator 9 is transmitted through the piping and adheres to the final stage expansion mechanism 14 and its vicinity. It is also possible to melt and remove solidified oil.

Further, regarding this sixth embodiment, although the drawing shows a case where it is applied to what is shown in the second embodiment, it can also be applied to the third, fourth, and fifth embodiments. .

Next, FIG. 7 shows a seventh embodiment of the present invention.
This is a partial cross-sectional diagram of the system. In this seventh embodiment, the high temperature chamber 2 and the low temperature chamber 3 are connected by an air passage 25.26, and the air passage 25.26 includes dampers 18g, 1
8h is provided.

According to this seventh embodiment, by opening the dampers 18g and 18h, high-temperature air generated in the high-temperature chamber 2 can be directly supplied to the low-temperature chamber 3. Therefore, even when the test chamber 1 is in use, high-temperature air can be sent to the low-temperature chamber 3 to remove frost adhering to the evaporator 9 of the ultra-low temperature generator.

In addition, in this seventh embodiment, although the drawing shows the case where the ultra-low temperature generator of the first embodiment is applied, it is not limited to this, and the devices of the second to sixth embodiments may also be used. It can be applied. When the second to sixth embodiments are adopted as the ultra-low temperature generator, the final stage expansion mechanism 14 is fully opened to remove frost from the evaporator 9.
Operation of supplying hot gas refrigerant to evaporator 9 and high temperature chamber 2
If this is combined with supplying high-temperature air to the cold room 3 from the evaporator 9, the air that has been cooled once by melting the frost in the evaporator 9 can be reheated by the hot gas refrigerant via the heating heat exchanger 24. I can do it. As a result, it is possible to reduce the amount of heating by sending high-temperature air from the high-temperature chamber 2 to the low-temperature chamber 3. This is particularly effective when it is not desired to stop the operation of the refrigeration cycle due to the start-up when the refrigeration cycle is restarted.

Furthermore, in the ultra-low temperature generator shown in the first to seventh embodiments, an inert gas such as nitrogen gas having a boiling point lower than the generation temperature by the ultra-low temperature generator is used as the fluid flowing in the apparatus. Since frost formation on low temperature parts such as the evaporator 9 and the like can be prevented, defrosting operation becomes unnecessary.

〔Effect of the invention〕

According to the invention recited in claim 1 of the present invention as described above, the test chamber is provided with an ultra-low temperature generator and a heating device for creating an environment in the test chamber, and the ultra-low temperature generator is configured with a refrigeration cycle. A refrigeration cycle consists of a single compressor that compresses a mixture of refrigerants with different boiling points, a condenser that condenses the compressed refrigerant, cooling units installed in multiple stages, and a high-pressure cooling unit in the final stage. A final stage expansion mechanism connected to the side, an evaporator connected to this expansion mechanism and generating ultra-low temperature, and piping that returns refrigerant from the evaporator to the cooling units of each stage and to the compressor. and a gas-liquid separator that separates the condensed refrigerant into a gas refrigerant and a liquid refrigerant; An intermediate heat exchanger that cools with a low-pressure low-temperature refrigerant flowing through a flow path, an expansion mechanism that reduces the pressure of the separated liquid refrigerant, and piping that guides the reduced-pressure low-pressure low-temperature refrigerant to the other flow path of the intermediate heat exchanger. The expansion mechanism of the final stage is connected to the refrigerant outlet side of one flow path in the intermediate heat exchanger of the cooling unit of the final stage, and at least the expansion mechanism of the final stage is connected to the refrigerant outlet side of the intermediate heat exchanger of the final stage cooling unit.
The expansion mechanism has an adjustable opening degree, and by adjusting the opening degree of at least the final stage expansion mechanism, for example, when the opening degree is increased, an increase in evaporation pressure will trigger an intermediate heat exchange of the cooling unit. As the temperature on the low pressure side of the evaporator increases, the condensation rate of the high boiling point refrigerant in the mixed refrigerant decreases, and the refrigerant flowing into the evaporator becomes a mixed refrigerant with a large proportion of high boiling point refrigerant, so the temperature is relatively high. is obtained, so
It has the effect of easily producing a wide range of temperatures.

According to the second aspect of the present invention, the discharge side of the compressor in the ultra-low temperature generator and the refrigerant inlet side of the evaporator are connected by a hot gas bypass piping, and the hot gas bypass piping is opened and closed. By providing a valve or a valve whose opening degree can be adjusted, a mixed refrigerant with a high boiling point can be supplied to the evaporator in a high temperature state through the hot gas bypass piping, which not only has the effect of obtaining a wider range of temperatures, but also reduces the discharge from the compressor. The temperature of the mixed refrigerant is above room temperature, which is a high temperature level even in the refrigeration cycle, and has the effect of removing frost that adheres to the evaporator in ultra-low @ operation. Furthermore, according to the third aspect of the present invention, a heating heat exchanger is installed on the air inlet side or the air outlet side of the evaporator in the ultralow temperature generator, and the The hot gas bypass piping is connected to the refrigerant inlet side of the exchanger, and the hot gas bypass piping is provided with an on-off valve or a valve whose opening degree can be adjusted, so that the air is heated by the heating heat exchanger. A wide range of temperatures can be obtained, and the evaporator c. In addition to preventing the formation of frost, it is no longer necessary to provide an on-off valve in the main path, and pressure loss due to the on-off valve can be eliminated, which has the effect of improving the efficiency of the refrigeration cycle.

Furthermore, according to the invention described in claim 4 of the present invention, the refrigerant outlet side of the heating heat exchanger is connected to one flow path of the intermediate heat exchanger of the final stage cooling unit and the final stage expansion mechanism. The air is connected via another pipe to the pipe connecting the refrigerant inlet side of the compressor, and the air is heated by a heating heat exchanger using a hot gas refrigerant with a large proportion of refrigerant with a high boiling point discharged from the compressor. , The refrigerant flowing out from this heating heat exchanger is combined with the refrigerant flowing out from the high pressure side of the intermediate heat exchanger of the final stage cooling unit, and then guided to the final stage expansion mechanism. Since the pressure is reduced and the gas flows into the evaporator, a relatively high temperature can be obtained, and therefore a wider range of temperatures can be obtained. According to the fifth aspect of the present invention, the refrigerant outlet side of the heating heat exchanger is connected to the refrigerant inlet side of the expansion mechanism of at least one cooling unit of the cooling unit provided in multiple stages. The final stage expansion mechanism is completely idle.
By opening the on-off valve or adjustable opening valve installed in the hot gas bypass piping and allowing hot gas refrigerant to flow through the heating heat exchanger, frost that adheres to the evaporator during low-temperature operation is effectively removed. There is a potential effect.

Furthermore, according to the invention set forth in claim 6 of the present invention, a heating section is provided in the hot gas bypass piping for heating the expansion mechanism of the cooling unit of each stage and its vicinity by the refrigerant flowing through the hot gas bypass piping. As a result, in the event that the expansion mechanism of the cooling unit becomes clogged, the solidified oil can be melted and removed using a relatively high temperature generating mode such as a defrosting mode. be.

Furthermore, according to the invention described in jiff claim 7 of the present invention, a test chamber, a high temperature chamber, and a low temperature chamber are provided, and the test chamber and the high temperature chamber, and the test chamber and the low temperature chamber are connected by air channels, respectively. At the same time, the height 1 fl 21 and the cold room are also connected by an air flow path, and dampers are provided in each air flow path, and by selectively opening the dampers, even during the test, the high temperature room can be connected to the low temperature room. Therefore, there is an effect that the frost that adheres to the evaporator during low @ operation can be removed by using the high temperature air from the high temperature room side.

According to the invention described in claim 8 of the present invention, since an inert gas having a boiling point lower than the generation temperature of the ultra-low temperature generator is used as the fluid flowing in the ultra-low temperature generator, the low temperature of the evaporator, etc. This has the effect of eliminating the need for unboxing operations, as lightning can be prevented from striking the parts.

[Brief explanation of drawings]

Figure 1, Figure 2, Figure 3, Figure 4, Figure 5, Figure 6, and Figure 7 are the first, second, third, and fourth figures of the present invention, respectively.
, 5th, 6th, and 7th examples, and is a system diagram with a part cut away. 1... Test chamber, 2... High temperature room, 3... Low temperature room, 4... Compressor, 5... Condenser, 6... Supercooler, ■... First stage cooling unit,
■... Second stage cooling unit, 7, 8... Intermediate heat exchanger, 9... Evaporator, 10.11... Gas-liquid separator,
12.13... Expansion mechanism, 14... Final stage expansion mechanism, 15... Heater, 16... High temperature room blower, 1
7... Blower for cold room, 18a-18h... Damper, 19... Hot gas bypass piping, 20... Bypass piping, 21.22... Opening/closing valve, 23... Expansion mechanism, 24 ...Heating heat exchanger, 12'13'・
・・Expansion machine 4 Port 12・Expansion mechanism 13−・1・“

Claims (1)

[Scope of Claims] 1. An environmental testing device comprising a test chamber, and an ultra-low temperature generator and a heating device for creating an environment within the test chamber, wherein the ultra-low temperature generator is configured with a refrigeration cycle, and the refrigeration cycle is A single compressor that compresses a complex mixture of refrigerants with different boiling points, a condenser that condenses the compressed refrigerant, a cooling unit installed in multiple stages, and a system connected to the high pressure side of the final stage cooling unit. a final stage expansion mechanism; an evaporator connected to this expansion mechanism and generating ultra-low temperature;
and piping that returns the refrigerant from the evaporator to the compressor via the cooling units at each stage, and the cooling unit at each stage separates the condensed refrigerant into gas refrigerant and liquid refrigerant. an intermediate heat exchanger that guides the separated gas refrigerant into one flow path and cools it with a low-pressure low-temperature refrigerant flowing through the other flow path; and an expansion mechanism that reduces the pressure of the separated liquid refrigerant. , and a pipe that guides a reduced pressure, low-pressure, low-temperature refrigerant to the other flow path of the intermediate heat exchanger, and the final stage expansion mechanism is configured of a pipe that leads the reduced pressure low-pressure low-temperature refrigerant to the other flow path of the intermediate heat exchanger of the final stage cooling unit. An environmental test device, characterized in that it is connected to a refrigerant outlet side and that at least the final stage expansion mechanism is an expansion mechanism whose opening degree can be adjusted. 2. The discharge side of the compressor in the ultra-low temperature generator and the refrigerant inlet side of the evaporator are connected by a hot gas bypass piping, and the hot gas bypass piping is provided with either an on-off valve or a valve whose opening degree can be adjusted. , install either an on-off valve or an adjustable valve in the piping connecting the other flow path of the intermediate heat exchanger of the final stage cooling unit and the refrigerant outlet side of the evaporator, and install other valves in parallel with this piping. 2. The environmental testing device according to claim 1, further comprising a pipe and an expansion mechanism provided in said other pipe. 3. A heating heat exchanger is installed on either the air inlet side or the air outlet side of the evaporator in the ultra-low temperature generator, and the discharge side of the compressor and the refrigerant inlet side of the heating heat exchanger are connected. The hot gas bypass piping is connected to the other flow path of the final stage intermediate heat exchanger and the refrigerant outlet side of the evaporator. 2. The environmental testing device according to claim 1, wherein the refrigerant outlet side of the heating heat exchanger is connected to the pipe connecting the heating heat exchanger via a bypass pipe, and an expansion mechanism is provided in the bypass pipe. 4. Connect the refrigerant outlet side of the heating heat exchanger to the pipe connecting one flow path of the intermediate heat exchanger of the final stage cooling unit and the refrigerant inlet side of the final stage expansion mechanism to another pipe. 4. The environmental testing device according to claim 3, wherein the environmental testing device is connected via a. 5. A refrigerant outlet side of the heating heat exchanger is connected via piping to a refrigerant inlet side of an expansion mechanism of at least one cooling unit of the cooling units provided in multiple stages. 3. The environmental test device described in 3. 6. The environmental test according to claim 2, characterized in that the hot gas bypass piping is provided with a heating section that heats the vicinity of the expansion mechanism of the cooling unit of each stage by the refrigerant flowing through the hot gas bypass piping. Device. 7. A test chamber, a high temperature chamber, and a low temperature chamber are provided, a heating device is installed in the high temperature chamber, and the ultralow temperature generator according to any one of claims 1 to 6 is connected to the low temperature chamber; The test chamber and the high temperature room and the test room and the low temperature room are each connected by an air flow path, and the high temperature room and the low temperature room are also connected by an air flow path, and each air flow path is provided with a damper. Environmental test equipment. 8. The environmental testing device according to any one of claims 1 to 7, wherein an inert gas having a boiling point lower than the temperature generated by the ultra-low temperature generator is used as the fluid flowing in the ultra-low temperature generator.