JP2541741B2 - Two-stage compression refrigeration apparatus capacity control method and apparatus - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention requires a temperature of air to be cooled ranging from a low temperature of 0 to -60 ° C. to an ultra-low temperature, and has an accuracy of ± 0.2 ° C. with respect to an appropriate temperature in this temperature range. The present invention relates to a capacity control method for a two-stage compression refrigerating apparatus using an economizer used for a constant temperature apparatus such as a semiconductor environment test apparatus that needs to maintain the temperature and its apparatus. In particular, the invention is
The present invention relates to a capacity control method for a two-stage compression refrigeration system and an apparatus using an economizer equipped with a gas cooler in a pipe connecting a low-stage discharge gas pipe and a high-stage intake gas pipe of a two-stage compressor.

[0002]

2. Description of the Related Art Conventionally, in this type of thermostat, a combination of liquid nitrogen and an electric heater has been exclusively used.

In addition to this, it is easily conceivable to apply a conventionally known one-source refrigerator or two-source refrigerator to this type of thermostatic device.

[0004]

The boiling point (-195.8 ° C.) of conventional liquid nitrogen is low.
While evaporating the liquid nitrogen, the test sample is cooled to an appropriate temperature.

Then, an environmental test is conducted by maintaining the temperature at a constant temperature of, for example, -3 ° C, -45 ° C, -55 ° C using an electric heater or the like.

[0006] Therefore, there is a drawback that the consumption of liquid nitrogen is heavy, it is necessary to always prepare a spare liquid nitrogen, continuous operation cannot be performed, and it is expensive.

In addition, the constant temperature device has a conveyor C from the side.
There is an operation hole S, etc., through which the test sample is carried in, the test head T is operated from above the thermostat to perform the test, and the test sample is taken out. Therefore, there is a risk that the nitrogen gas may leak from the opening and closing gaps of the operation hole S and the like and suffocate, and the working environment is bad.

Further, a conventionally known single-source refrigerating device is used as a thermostatic device, and a thermostatic device requiring a cooled air temperature ranging from a low temperature of 0 to -60 ° C. to an ultra-low temperature is usually a single-stage compressor. Since the two-stage compressor is used together, the device is complicated and expensive. That is, the room temperature is 0-
In the temperature range of 30 ° C, a single stage compressor is used,
In the low to very low temperature range of -60 ° C, the use of a two-stage compressor is common knowledge in this type of industry.

In the refrigeration cycle, when the evaporation temperature is high, that is, when the set temperature is high, the refrigerating capacity is large, and conversely, when the evaporation temperature is low, that is, the set temperature is low, the intake gas Since the specific volume is large, the refrigerating capacity is small. On the other hand, the refrigerating load does not change much at 0 to −60 ° C. That is, since the refrigerating capacity changes depending on the evaporation temperature, a compressor whose capacity can be controlled is required to operate the refrigerating capacity in a well-balanced manner with respect to the load.

However, the present situation is that there is no compressor with a capacity control mechanism attached to a compressor of a single refrigeration system or a dual refrigeration system having a small refrigeration load. Therefore, if the single compressor without this capacity control function cools the cooled air temperature from 0 to -60 ° C to ultra-low temperature, the single-stage compressor with a small compressor capacity operates at -60 ° C. If you do, the compressor overheats, and the single-stage compressor alone cannot handle it. Further, in a two-stage compressor having a large compressor capacity, when the cooling operation is performed at 0 ° C., the compressor capacity becomes too large and an excessive refrigerating capacity occurs, making it difficult to maintain the temperature at the set temperature (0 ° C.). A two-stage compressor alone cannot handle this.

As a result, overheating occurs or excess refrigerating capacity is generated, and it becomes difficult to maintain the temperature at the set temperature. Therefore, in the one-source refrigerating apparatus, a high temperature is a single stage compressor and a low temperature is low. Would have to use a two-stage compressor.

Further, in a thermostatic device such as a semiconductor environment testing device, the cooled air is cooled down to a constant temperature within a temperature range from room temperature to the ultra low temperature in about 30 minutes when cooling is lowered from the viewpoint of workability and the like. It is necessary to have a freezing capacity. Therefore, a refrigerating compressor having a refrigerating capacity about three times the refrigerating load is required, but this type of thermostatic device is small in scale, has a relatively small refrigerating load, and the above-mentioned drawbacks directly appear.

Further, since the dual refrigerating device also has the same refrigerating capacity characteristics, there is an excess in the refrigerating capacity with respect to the set temperature, and this surplus refrigerating capacity is heated by the electric heater to maintain the set temperature, thus saving energy. There is a drawback against

The present invention relates to a two-stage compression refrigerating apparatus using an economizer used for a constant temperature apparatus such as a semiconductor environment testing apparatus, and the capacity of the two-stage compression refrigerating apparatus which does not generate an excessive refrigerating capacity by using only the two-stage compressor. It is an object to provide a control method and its device. Specifically, it is possible to simplify temperature control and save energy in the two-stage compression refrigeration system in which a gas cooler is interposed in a pipe connecting a low-stage discharge gas pipe and a high-stage intake gas pipe of a two-stage compressor. An object of the present invention is to provide a capacity control method for a stage compression refrigeration system and an apparatus therefor.

[0015]

In order to solve this problem, the present invention uses an economizer used in a constant temperature device such as a semiconductor environment test device as its capacity control method.
In a two-stage compression refrigeration system equipped with a gas cooler in the pipe connecting the low-stage discharge gas pipe and the high-stage intake gas pipe of the two-stage compressor, the low-stage intake gas pipe of the two-stage compressor is branched from this gas cooler. Expansion valve for the economizer, which is located in the branch liquid pipe that connects the economizer and the gas cooler from the outlet of the condenser that is connected to the high-stage discharge gas pipe of the two-stage compressor, respectively The liquid supply valve and the expansion valve for the gas cooler and the liquid supply valve are operated by the set temperature signal at the cooled fluid outlet of the evaporator.

Then, the liquid supply to the economizer is stopped and the liquid supply to the gas cooler is started, and the low-stage discharge gas of the two-stage compressor is sent from the gas cooler to the low-stage intake gas pipe side of the two-stage compressor. return.

Further, the residual gas returned to the low-stage intake gas pipe side of the gas cooler is sucked into the high-stage intake gas pipe side of the two-stage compressor.

Further, as the capacity control device, an economizer used for a constant temperature device such as a semiconductor environment test device is used, and a gas cooler is connected to the pipe connecting the low-stage discharge gas pipe and the high-stage intake gas pipe of the two-stage compressor. In the two-stage compression refrigeration system equipped with, the gas cooler is provided with a branch gas pipe connected to the low-stage suction gas pipe of the two-stage compressor.

Further, an automatic valve is interposed in the branch gas pipe, a temperature sensor for detecting the outlet temperature of the cooled fluid of the evaporator, and a temperature which can be set to an arbitrary temperature connected to the temperature sensor. Provide a controller.

An expansion valve and a liquid supply valve for the economizer and the gas cooler are provided in each of the two branch liquid pipes provided at the refrigerant outlet of the condenser, and the temperature controller, the economizer and the gas cooler are connected to the expansion valve. A signal line connecting the expansion valve and the liquid supply valve is provided.

A signal line connecting the automatic valve and the temperature controller is provided.

[0022]

The gas cooler 23 is connected to the pipe 15 connecting the low-stage discharge gas pipe 13 and the high-stage intake gas pipe 14 of the two-stage compressor 8 by using the economizer 4 used in the constant temperature device 2 such as the semiconductor environment test device 1. In the two-stage compression refrigeration system 3 provided with
When the temperature of the temperature sensor 6 for detecting the outlet temperature of the cooled fluid outlet 5a of the evaporator 5 reaches the set temperature of the temperature controller 7, the controller 7 issues a set temperature signal.

With this set temperature signal, the expansion valve / supply liquid valve 19, which is interposed between the two branch liquid pipes 18 and 24 at the outlet of the condenser 17 connected to the economizer 4 and the gas cooler 23,
25 is opened and closed via signal lines 26 and 27. Then, the liquid supply to the economizer 4 is stopped, the liquid supply to the gas cooler 23 is started, and the automatic valve 10 of the branch gas pipe 9 from the gas cooler 23 to the low stage intake gas pipe 12 is opened.

Then, the low-stage discharge gas pipe 1 of the two-stage compressor 8
3 and the low temperature liquid supplied from the expansion valve / supply liquid valve 25 through the branch liquid pipe 24 from the outlet of the condenser 17 is gasified through the gas cooler 23 and flows into the low stage intake gas pipe 12. To do.

The low-stage suction pressure of the compressor 8 rises due to the gasification pressure of the refrigerant liquid supplied from the gas cooler 23 through the branch liquid pipe 24 at the outlet of the condenser 17.
The low-stage suction pressure, the low-stage discharge pressure, and the high-stage suction pressure become the same pressure. Therefore, the gas compression operation on the low stage side A is not performed, and the power required for gas compression is not required.

In this case, of the gas from the gas cooler 23, what is sucked into the high-stage suction gas pipe 14 is the low-stage suction pressure, the low-stage discharge pressure, and the high-stage suction of the compressor 8 which have the same pressure. Only the excess above the pressure is inhaled. Then, the gas is compressed on the high-stage side B and is discharged from the high-stage discharge gas pipe 16 to the condenser 17
Leading to.

Therefore, since only the surplus portion is sucked into the high-stage intake gas pipe 14, the amount of gas into the high-stage intake gas pipe 14 of the two-stage compressor 8 is reduced, and the high-stage discharge pressure is reduced. Will fall. Therefore, since the refrigerating capacity and power of the compressor 8 do not need to perform the gas compression work on the low-stage side A and the gas compression work on the high-stage side B for the reduction of the gas amount, the gas compression work amount is reduced. It can be seen that the capacity control works effectively.

The heating of the gas due to recompression at this time can be prevented by cooling with the gas cooler 23.

[0029]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A capacity control method for a two-stage compression refrigerating apparatus and an embodiment of the apparatus according to the present invention will be described below in detail with reference to the accompanying drawings.

FIG. 1 shows an outline of a semiconductor environment test apparatus, FIG. 2 shows a two-stage compression refrigeration apparatus using the gas cooler of the present invention, and FIG. 3 shows a conventional two-stage compression refrigeration apparatus. It is shown.

The semiconductor environment test apparatus 1 has a constant temperature apparatus 2 connected to a later-described two-stage compression / refrigeration apparatus 3 by a duct D, and a semiconductor placed on a conveyor C and traveling is set to a certain degree according to each application. The test is carried out while maintaining the temperature.

The constant temperature is −3 ° C., −45 ° C., and −55 ° C. depending on the use of semiconductor, respectively, and is ±±.
This is the temperature at which the environmental test is performed while maintaining the accuracy of 0.2 ° C. for about 48 hours.

Then, the test sample is returned from the thermostatic device 2 to the heating room H by the conveyor C, the semiconductor is returned to room temperature in the heating room H, and the semiconductor environmental test is completed.

Using the gas cooler used in the present invention,
The two-stage compression refrigeration system 3 including a one-way refrigeration system uses the conventional two-stage compression refrigeration system 3a illustrated in FIG.

The economizer 4 has a heat transfer tube 4a therein which is connected to a high-stage discharge gas tube 16 of a later-described two-stage compressor 8 via a condenser 17. Then, from the one branch liquid pipe 18 of the two branch liquid pipes 18 and 24 provided at the outlet of the condenser 17, the expansion valve / liquid supply valve 1 for the economizer is provided.
The high-pressure liquid is supplied from the liquid supply pipe 4b to the outer periphery of the heat transfer pipe 4a as a low-temperature liquid via 9

The supplied low-temperature liquid removes heat of vaporization from the high-pressure liquid in the heat transfer pipe 4a, is gasified, flows from the gas outlet 4c to the economizer return gas pipe 20, and supercools the high-pressure liquid from the condenser 17. To do.

The evaporator 5 is connected to the supercooled liquid pipe 21 from the economizer 4 through a low-stage expansion valve 22, and the expansion valve 22 takes away heat from the supercooled liquid having a low pressure to be cooled. Cool the fluid.

The temperature sensor 6 is provided at the cooled fluid outlet 5a of the evaporator 5 and detects the temperature of the outlet 5a.

The temperature controller 7 is connected to the temperature sensor 6 and can be set to an arbitrary temperature. The temperature sensor 6 sets the temperature of the controller 7 (temperature in the range of 0 to -30 ° C.). ) Is detected, a set temperature signal is emitted.

The two-stage compressor 8 has a piston displacement of 2:
1 is composed of a low-stage side A compressor and a high-stage side B compressor, and the gas outlet 5b of the evaporator 5 is connected to the low-stage intake gas pipe 12. Then, the low-stage discharge gas pipe 1 of the two-stage compressor 8
3 and the high-stage intake gas pipe 14 are connected by a pipe 15, and the high-stage discharge gas pipe 16 is connected to the inlet of the condenser 17.

The branch gas pipe 9 has a low end discharge gas pipe 1 at the base end.
3 is branched from a gas cooler 23 provided in a pipe 15 that connects the high-stage intake gas pipe 14 with the automatic valve 10 at the tip.
Through the low-stage intake gas pipe 12.

Further, in the gas cooler 23, the branch liquid pipe 18 from the outlet of the condenser 17 to the expansion valve / supply liquid valve 19
The low temperature liquid supplied to the economizer 4 via the is supplied via the economizer return gas pipe 20.

Then, the high pressure liquid from the branch liquid pipe 24 from the outlet of the condenser 17 is directly supplied to the gas cooler 23 as a low temperature liquid through the expansion valve / supply liquid valve 25.

Then, the low-temperature liquid supplied to the gas cooler 23 exchanges heat with the gas from the low-stage discharge gas pipe 13 to the high-stage intake gas pipe 14, and is itself gasified to become the high-stage intake gas pipe 14.
To cool the gas to.

The automatic valve 10 is interposed in the branch gas pipe 9 and is connected to the temperature controller 7 by the signal line 11. When the temperature sensor 6 detects the set temperature, the set temperature signal from the controller 7 is output. It is opened upon receipt.

The signal lines 26 and 27 connect the temperature controller 7 and the expansion valve / supply valve 19 and 25, respectively. When the temperature sensor 6 detects the set temperature, the set temperature signal from the controller 7 is sent. Upon receipt, the expansion valve / supply valve valve 19 is closed and the valve 25 is opened.

That is, when the temperature sensor 6 detects the set temperature, the supply of liquid to the economizer 4 is stopped and the supply of liquid to the gas cooler 23 is started.

Since the automatic valve 10 interposed in the branch gas pipe 9 from the gas cooler 23 to the low-stage intake gas pipe 12 is opened, the low-stage intake gas pipe 12 and the gas cooler 23, that is, the low-stage discharge gas pipe 13 and the high-stage intake gas pipe 13 The pressures of the stage intake gas pipes 14 become equal.

As a result, the low-stage side A of the two-stage compressor 8
Does not perform compression between the suction and discharge gas pipes 12 and 13,
It will be performed only on the high-stage side B of the two-stage compressor 8.

The compression operation on the high-stage side B is performed by the low-stage intake gas of the gas supplied from the branch liquid pipe 24 at the outlet of the condenser 17 of the gas cooler 23 through the expansion valve / supply liquid valve 25. Excess gas above the equalized gas pressure of the pipe 12, the low-stage discharge gas pipe 13, and the high-stage intake gas pipe 14 is compressed.

Further, these gas pipes 12 and 1 having the same pressure
The pressures in 3 and 14 are commensurate with the heat loads of the evaporator 5 and the economizer 4.

In this state, since the low-stage discharge temperature and the high-stage discharge temperature are maintained at proper constant temperatures, the lubricating oil system operates normally and the capacity control of the low-stage side A of the two-stage compressor 8 is performed. Will work effectively.

Next, when the temperature sensor 6 at the cooled fluid outlet 5a of the evaporator 5 has not reached the set temperature, the temperature controller 7 does not issue the set temperature signal, so the automatic valve 10
Is closed, the expansion valve / liquid supply valve 19 is opened, and the valve 25 is closed.

As a result, the low-stage side A of the two-stage compressor 8
The gas pressures of the suction and discharge gas pipes 12 and 13 do not become the same pressure, and the low pressure side A and the high pressure side B act as a conventional two-stage compressor.

Then, the high pressure liquid at the outlet of the condenser 17 is not supplied to the gas cooler 23 via the branch liquid pipe 24 but is supplied to the economizer 4 via the expansion valve / supply liquid valve 19 via the branch liquid pipe 18. Since it is liquid, it is supplied as a low temperature liquid from the liquid supply pipe 4b to the outer periphery of the heat transfer pipe 4a.

This low temperature liquid takes heat of vaporization from the high pressure liquid inside the heat transfer tube 4a, gasifies and flows into the economizer return gas pipe 20 from the gas outlet 4c, and supercools the high pressure liquid from the condenser 17.

That is, when the temperature sensor 6 at the cooled fluid outlet 5a of the evaporator 5 detects a temperature equal to or lower than the set temperature, it operates as a two-stage compression refrigeration system with a gas cooler using an economizer.

Next, the conventional capacity control is not performed (100
Table 1 shows a comparison between the refrigerating capacity and power of the two-stage compressor in which the low-stage side A is unloaded.

[0059]

[Table 1]

As described above, in the low-stage side unloading state of the present invention, by setting the evaporator outlet air set temperature of 0 to -30 ° C. to the evaporation temperature of −40 ° C. or higher, compression is performed against heat load. The refrigerating capacity of the machine can be reduced.

[0061]

As described above, according to the present invention, when the set temperature reaches the set temperature when the set temperature is relatively high (0 to -30 ° C),
The high-pressure liquid at the outlet of the condenser 17 is directly supplied to the gas cooler 23 without being supplied to the economizer 4. Then, the automatic valve 10 provided in the branch gas pipe 9 is opened to increase the low-stage suction pressure to equalize the low-stage discharge pressure, so that the low-stage side A of the two-stage compressor 8 does not perform compression work, and The stage side B performs the compression work, and the refrigerating capacity of the high stage side B is mainly effective.

The refrigerating capacity on the high-stage side B is 0 to -30.
Since the heat load of the evaporator 5 is commensurate with the set temperature of ° C, the control for maintaining the temperature becomes easy.

Further, since the low-stage side A of the two-stage compressor 8 does not perform compression work, the low-stage side A has only friction and the shaft power of the two-stage compressor is reduced, so that energy saving can be achieved.

Further, the two-stage compressor 8 of the present invention has a range of 0 to -3.
Since it operates like a single-stage compressor with respect to the set temperature of 0 ° C., it is not necessary to provide a single-stage compressor in addition to the conventional two-stage compressor, and the device itself can be simplified.

[Brief description of drawings]

FIG. 1 is a schematic view of a semiconductor environment test apparatus of the present invention seen from above.

FIG. 2 is a refrigerant pipe system diagram of a two-stage compression refrigeration system of the present invention.

FIG. 3 is a refrigerant pipe system diagram of a conventional two-stage compression refrigeration system.

[Explanation of reference numerals] 1 semiconductor environment test device 2 thermostatic device 3 two-stage compression refrigeration device of the present invention 3a conventional two-stage compression refrigeration device 4 economizer 4a heat transfer pipe 4b liquid supply pipe 4c gas outlet 5 evaporator 5a cooled fluid Outlet 5b Gas outlet 6 Temperature sensor 7 Temperature controller 8 Two-stage compressor 9 Branch gas pipe 10 Automatic valve 11 Signal line 12 Low-stage intake gas pipe 13 Low-stage discharge gas pipe 14 High-stage intake gas pipe 15 Piping 16 High-stage discharge Gas pipe 17 Condenser 18 Branch liquid pipe 19 Economizer expansion valve / supply valve 20 Economizer return gas pipe 21 Supercooling liquid pipe 22 Low-stage expansion valve 23 Gas cooler 24 Branch liquid pipe 25 Gas cooler expansion valve also Liquid supply valve 26, 27 Signal line A Low stage side B High stage side C Conveyor D Duct H Heating room S Operation hole T Test head

Claims (2)

(57) [Claims] [Claim 1] used in the constant temperature device such as a semiconductor environmental tester
That was used economizer, the two-stage compression refrigeration apparatus equipped with a gas cooler to the pipe connecting the low-stage discharge gas pipe and the high stage suction gas pipe of the two-stage compressor, the gas cooler
Branched gas to the lower stage intake gas pipe of the two-stage compressor
For the automatic valve interposed in the pipe and the high-stage discharge gas pipe of the two-stage compressor
From the connected condenser outlet, economizer and
Economies interposed in the branch liquid pipe that connects the gas cooler
Expansion valve and liquid supply valve for gas turbine and expansion valve and liquid supply for gas cooler
Valve and the set temperature signal at the cooled fluid outlet of the evaporator
Operate , stop the liquid supply to the economizer and start the liquid supply to the gas cooler, return the low-stage discharge gas of the two-stage compressor from the gas cooler to the low-stage intake gas pipe side of the two-stage compressor, A capacity control method for a two-stage compression refrigeration system, characterized in that the residual gas returned to the low-stage intake gas pipe side of the gas cooler is sucked into the high-stage intake gas pipe side of the two-stage compressor. 2. A two-stage compression system in which an economizer used in a constant temperature device such as a semiconductor environment test device is used and a gas cooler is provided in a pipe connecting a low-stage discharge gas pipe and a high-stage intake gas pipe of a two-stage compressor. In refrigeration equipment, this gas cooler
A branch gas pipe that connects to the low-stage suction gas pipe of the two-stage compressor is installed.
Only, it provided interposed the automatic valve in the branch gas pipe, a temperature sensor for detecting the outlet temperature to be cooled fluid outlet of the evaporator, and any temperature settable temperature controller in conjunction with a temperature sensor the provided, condenser respective two branch liquid pipe provided in the refrigerant outlet is provided an expansion valve and liquid supply valve to economizer gas cooler, the temperature controller and the expansion valve to the economizer gas cooler A capacity control device for a two-stage compression refrigeration system , comprising a signal line for connecting the liquid supply valve and a signal line for connecting between the automatic valve and the temperature controller.