JPH04192B2 - - Google Patents

Description

[Detailed description of the invention] [Object of the invention] (Industrial application field) The present invention operates at a working gas pressure near atmospheric pressure,
This relates to a precooling circuit for refrigerators in the low-temperature range (for example, Stirling cycle refrigerators, Gifford-McMahon cycle refrigerators, etc.) that generate refrigeration at extremely low temperatures by cooling the radiator with another refrigerator or low-temperature refrigerant.

(Prior Art) An example of a conventional precooling method for this type of refrigerator is disclosed in US Pat. No. 4,335,579. That is, as shown in FIG. 5, the refrigerator in the high temperature region generates refrigeration output in two temperature regions, and a member 24 with high thermal conductivity is assembled in the refrigeration section 8 on the high temperature side. , are thermally connected to the surfaces of the cylinders 15 and 16 of the refrigerator in the low temperature region. In this way, during the precooling period from the start of operation to the steady state of the refrigerator in the low temperature region, the refrigeration output generated in the high temperature side/refrigeration section 8 of the refrigerator in the high temperature region is used to cool the refrigerator in the low temperature region. The cylinders 15 and 16 are rapidly cooled, and the precooling time of the refrigerator in the low temperature region is shortened. When the refrigerator in the low-temperature region is in a steady state, the member 24 acts as a thermal anchor, and the refrigeration output generated in the refrigeration section 8 serves to remove the heat intruding from room temperature through the cylinders 15 and 16.

(Problems to be Solved by the Invention) However, in the above-mentioned precooling method in which the cylinder wall is cooled by another refrigerator, the precooling time cannot be shortened by rapidly cooling the regenerator or expansion space of the refrigerator in the low temperature region. The disadvantage is that it cannot be done.

That is, when the radiator 21a in the low temperature region is cooled with the refrigeration output in the high temperature region and the refrigerator in the cold region is operated, the regenerator is cooled by the refrigeration output generated by the expansion work of the working gas in the expansion space 20. However, if the working gas pressure of the low-temperature region refrigerator is limited to around atmospheric pressure, the refrigeration output will be small and the cooling time will be long. Furthermore, since the regenerator 19 acts as a heat exchanger between the working gas and the regenerator material, the working gas cooled by the refrigerator in the high temperature region in the heat radiation section precools the low temperature side of the regenerator or the expansion space. has no effect.

The technical object of the present invention is to provide a precooling method free from such problems.

[Structure of the invention]

(Means for Solving the Problems) In order to solve the above technical problems, the technical measures taken in the present invention include a compression space, an expansion space, and a heat radiator and a regenerator interposed between the two spaces. In a refrigerator that cools the radiator with a refrigerant of another refrigerator or a low-temperature refrigerant, the radiator and the regenerator are provided between the compression space and the expansion space, in parallel with each other, only during precooling of the refrigerator. A one-way valve that allows the flow of working gas only from the expansion space to the compression space is provided.

(effect) The effects of the above technical means are as follows.

That is, during precooling, an on-off valve disposed in a pipe communicating the high temperature section and the low temperature section is opened, and the one-way valve is installed so as to open when the working gas flows from the low temperature section to the high temperature section.

During the half-cycle when the working gas moves from the compression space of the refrigerator in the low-temperature region to the expansion space, all the working gas passes through the radiator, and at this time, it is cooled by the refrigeration of the refrigerator in the high-temperature region, and this cooled gas passes through the radiator. The working gas cools the regenerator material, and the working gas itself gains heat from the regenerator material, heats up, and reaches the expansion space. Next, during the half cycle in which the working gas moves from the expansion space to the compression space, a
Since the one-way valve is in the open state, a portion of the working gas passes through the precooling circuit and directly flows into the high temperature area (for example, the compression space, etc.). The remaining working gas passes through the regenerator, and at this time, the refrigeration that was transferred from the working gas to the regenerator in the previous half cycle is recovered and flows into the compression space via the radiator. In this way, during the half cycle in which the working gas moves from the low-temperature section to the high-temperature section, the more the amount of working gas passing through the precooling circuit is compared to the amount of gas passing through the regenerator, the more the reciprocating flow rate of the working gas passing through the regenerator increases. There is an imbalance, and the regenerator material is quickly cooled down to the temperature of the working gas flowing out of the radiator. Conversely, as the reciprocating flow rate of the working gas passing through the regenerator becomes equal, the amount of heat further transferred between the regenerator material and the working gas in each half cycle becomes equal, and the regenerator material is not cooled.

When the temperature of the cold storage material and the expansion space approaches the temperature of the working gas of the high-temperature range refrigerator flowing through the radiator or the temperature of the low-temperature refrigerant and the precooling is completed, the on-off valve provided in the precooling circuit is closed, and the low-temperature range refrigerator Prevent heat leaks from occurring due to movement of working gas from high-temperature parts to low-temperature parts.

(Example) Hereinafter, an example of the present invention will be described based on FIGS. 1 to 4.

In FIG. 1, a compression space 101, a radiator 10
2. A pre-cooling circuit 105 in which the compression space 101 and the expansion space 104 are short-circuited is provided in parallel to the working space in which the regenerator 103 and the expansion space 104 are sequentially communicated.
Furthermore, the pre-cooling circuit 105 has an on-off valve 106 located as close to the compression space 101 as possible, and a one-way valve 10 as close to the on-off valve 106 as possible.
7 is placed, and an on-off valve 106a is placed as close as possible to the expansion space 104. The one-way valve 1
07 opens when the working gas flows from the expansion space 104 to the compression space 101;
1 to close when the working gas flows toward the expansion space 104.

At the start of precooling, two on-off valves 106 and 106a in the precooling circuit 105 are opened. During the half cycle in which the working gas flows from the compression space 101 to the expansion space 104, the one-way valve 10 in the precooling circuit 105
7 is closed, all of the working gas in the compression space 101 passes through the heat radiation section 102, where it is cooled to around the temperature of the refrigerant flowing through the refrigerant pipe 108. When the cooled working gas passes through the regenerator 103, it cools the regenerator, raises its temperature, and flows into the expansion space 104. (When the working gas pressure is close to atmospheric pressure and the expansion work is small, the working gas temperature drops only slightly in the expansion space 104 due to the expansion work.) Next, the working gas flows from the expansion space 104 toward the compression space 101. During the flowing half cycle, the precooling circuit 10
The one-way valve 107 in the expansion space 104 is in a conductive state, and the working gas in the expansion space 104 flows from the regenerator 103 to the compression space 101 via the heat radiation part 102.
It is divided into a portion that passes through the precooling circuit 105 and flows directly into the compression space 101. In this way, as described in the (effect) section, the amount of working gas reciprocating in the regenerator 103 becomes unbalanced, producing a precooling effect. After the precooling is completed, the two on-off valves 106 and 106a are closed to minimize the increase in dead volume and heat intrusion due to the addition of the precooling circuit 105.

The on-off valve is the compression space 101 or the expansion space 10
4, if the one-way valves 109, 109a cannot be placed close to the compression space 101, as shown in FIG.
The on-off valve 110 may be placed as close to the expansion space 104 as possible, and the on-off valve 110 may be placed as close to the expansion space 104 in one direction 109a as possible.

In the case of a so-called multi-stage expansion low-temperature region refrigerator having two or more expansion spaces, the pre-cooling circuit is basically the same as in the one-stage expansion shown in FIGS. 1 and 2. 2
The stage expansion precooling circuit is shown in FIGS. 3 and 4. The on-off valve is a compression space 101 and two expansion spaces 104.
A, 104b, the precooling circuit is shown in FIG. That is, similar to FIG. 1, precooling circuits 105a and 105 are provided that short-circuit the compression space 101 and the first expansion space 104a and the compression space 101 and the second expansion space 104b, respectively, and the compression space 101 and the two expansion spaces are provided in the circuit. Space 104a,
Three on-off valves 106, 106a, 106b are arranged as close as possible to the on-off valve 194b, and one-way valves 107, 107a are provided as close as possible to the on-off valve 106 in each pre-cooling circuit. These one-way valves allow the working gas to enter each expansion space 1.
When flowing from 04b and 104a to the compression space 101, conduction occurs, and from the compression space 101 to each expansion space 104.
b, closed when flowing to 104a. If the three on-off valves are made conductive at the start of pre-cooling, the one-way valves 107 and 10 will open during the half cycle in which the working gas flows from the compression space 101 to the expansion spaces 104a and 194b.
Since 7a is closed, all the working gas is transferred to radiator 1.
02 and the first regenerator 103a. However, from each expansion space 104a, 104b, compression space 1
During the next half cycle when the working gas flows to 01, the two one-way valves are conductive, so the precooling circuits 105 and 10
A portion of the working gas passes through 5a to each expansion space 104.
The amount of working gas that flows directly into the compression space 101 from a, 104b and reciprocates between the regenerators 103a, 103b becomes unbalanced, producing a precooling effect.

In order to simplify this pre-cooling circuit, the circuit 105a that short-circuits the first expansion space 104a and the compression space 101 may be removed, although the pre-cooling time will be somewhat longer.

As for the spatial arrangement, when the on-off valve cannot be placed near the compression space 101 and the expansion spaces 104a, 104b, one-way valves 109, 10 are used as shown in FIG.
9b and 109a may be arranged as close as possible to the compression space 101, the first expansion space 104a, and the second expansion space 104b. At this time, on-off valves 110a, 110 are provided as close as possible to the two one-way valves 106b, 106a. In order to simplify the pre-cooling circuit, the circuit 105b that short-circuits the first expansion space 104a and the compression space 101 may be removed, although the pre-cooling time will be somewhat longer.

〔Effect of the invention〕

The present invention provides an on-off valve that opens only during precooling, and a one-way valve that opens only during precooling, although the freezing temperature of the refrigerant generated in the expansion space is higher than the temperature of the regenerator, but most of the refrigerant does not flow through the regenerator. It flows directly into the compression space via the valve. Therefore, at this time, the refrigerant flowing from the expansion space to the compression space does not heat the regenerator much, so that the precooling time of the refrigerator can be shortened.

[Brief explanation of drawings]

FIG. 1 is a conceptual diagram showing an embodiment of the precooling circuit according to the present invention, in which the on-off valve is disposed close to the compression space and the expansion space in one stage expansion, and FIG. Among the embodiments of the precooling circuit, FIG. 3 is a conceptual diagram showing a case where the on-off valve cannot be arranged close to the compression space and the expansion space in one-stage expansion. FIG. 4 is a conceptual diagram showing a case where the on-off valve can be arranged close to the compression space and two expansion spaces in the stage expansion, and FIG. A conceptual diagram showing a case where the compression space and two expansion spaces cannot be arranged close to each other, and FIG. 5 are sectional views of a refrigerator using a conventional precooling circuit. 101... Compression space, 102... Heat radiation part, 10
3...Regenerator, 104...Expansion space, 105...
Pre-cooling circuit, 106...on/off valve, 107...one-way valve.

Claims (1)

[Claims] 1. A refrigerator comprising a compression space, an expansion space, and a radiator and a regenerator interposed between the two spaces, and in which the radiator is cooled with a refrigerant from another refrigerator or a low-temperature refrigerant. , between the compression space and the expansion space, in parallel with the radiator and the regenerator, an on-off valve that opens only when precooling the refrigerator and a flow of working gas only from the expansion space to the compression space; A precooling circuit for a refrigerator that includes a one-way valve that allows for