JPH04136664A - Reverse starling cycle device - Google Patents

Abstract

PURPOSE:To retain performance of a device at a desired target value by a method wherein check valves provided between a compressor room and a buffer, and the buffer and a compressor room back pressure part are opened or closed selectively so that operation fluid compressed to have high pressure is accumulated in the buffer, whereby operation fluid volume in a reverse Starling cycle constituting part is increased. CONSTITUTION:During normal operation, if only a check valve 13 is opened from a state in which both check valves 13 and 14 are closed, operation gas which is compressed to have high pressure is accumulated in a buffer 15 through a one-way valve 12. As a result, pressure of the operation gas in a freezing circuit drops down, reaching temperature of a cold head rises up and freezing performance can be restricted. If the check valve 13 is closed and the check valve 14 is opened, the operation gas in the buffer 15 flows into a compressor room back pressure part 11 which is low pressure side and the pressure in the compressor room back pressure part 11 rises up, and therefore, the operation gas enters again the freezing circuit through another one-way valve 16 and gas volume in the freezing circuit returns to its original value, whereby the reaching temperature of the cold head 17 drops down, while freezing performance rises up.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to an inverted Stirling cycle device, and in particular to a device provided with means for controlling performance.

(Prior art) In a device that uses a reverse Stirling cycle, for example, a reverse Stirling refrigerator, a drive source such as a motor rotates a crankshaft, and an expansion piston and a compression piston are reciprocated via a rond to move the inside of the cylinder. The fluid is compressed and expanded to generate cold heat, and the cold heat is extracted and used.

By the way, in a conventional reverse Stirling cycle device, the amount of working gas sealed in the refrigeration circuit of a reverse Stirling cycle component, such as a reverse Stirling refrigerator, is constant after cooling, and the refrigeration performance is determined by this.

This will be explained in more detail with reference to the drawings regarding an actual device.

FIG. 2 is a diagram showing an example of a conventional configuration of an inverted Stirling refrigerator. As shown in the figure, a compression chamber 3 formed by a compression cylinder 1 and a compression piston 2 communicates with an expansion chamber 6 via a helium cooler 4, a regenerator 5, and a cold head 17. The expansion chamber 6 is defined by an expansion cylinder 7 and an expansion piston 8. The compression piston 2 and the expansion piston 8 are fitted with seals 9.10 to prevent leakage of working gas. A compression chamber 3 formed above and below the compression piston 2 and a compression chamber back pressure section 11
are connected via a one-way check valve 16 that allows fluid to flow only in the direction from the compression chamber back pressure section 11 to the compression chamber 3.

With the above configuration, a cryogenic temperature can be obtained by reciprocating the compression piston 2 and the expansion piston 8 with a predetermined phase difference. During cooling, working gas is replenished into the refrigeration circuit from the compression chamber back pressure section 11 via the one-way check valve 16, but after the situation becomes steady, the amount of working gas in the refrigeration circuit remains constant. Refrigeration performance cannot be changed. Also,
Since the working gas pressure in the refrigeration circuit remains high, the lifespan of seal rings 9, 10, etc. is short.

Although it is possible to control the refrigeration performance and extend the life of seal rings and the like by variable speed using an inverter, it has the drawback of high costs.

(Problems to be Solved by the Invention) The present invention provides a reverse Stirling cycle device capable of controlling the performance of the device in view of the above-mentioned problems of conventional reverse Stirling cycle devices, such as reverse Stirling refrigerators. That is the issue.

(Means for Solving the Problems) In order to solve the above problems, the present invention provides a reverse Stirling cycle device as exemplified above, between a compression chamber defined by a compression piston and a compression chamber back pressure section. A buffer is provided, and the compression chamber and the buffer are connected by piping equipped with a one-way valve and a stop valve that allow fluid to flow only in the direction from the compression chamber to the buffer, and the buffer and the compression chamber back pressure section are connected. A pipe equipped with a one-way valve that allows fluid to flow between the compression chamber back pressure section and the compression chamber only in the direction from the compression chamber back pressure section to the compression chamber. A method is adopted in which a control means is provided which connects the two stop valves by a line and controls the two stop valves according to the control target value.

(Function) Since the reverse Stirling cycle device of the present invention is configured as described above, the compression chamber and the buffer, and the buffer and the compression chamber back pressure section are selectively opened and closed to open and close the stop valves. The amount of working fluid in the reverse Stirling cycle component can be increased by storing the high-pressure working fluid in the buffer or returning it from the buffer to the compression chamber via the compression chamber back pressure section and the one-way valve. It becomes possible to maintain the performance of the fruiting device at a desired target value.

(Example) Examples of the present invention will be described in detail below based on the drawings.

FIG. 1 is a diagram showing an embodiment in which the present invention is applied to the inverted Stirling refrigerator previously explained in FIG. 2. Therefore, members having the same functions as those in FIG. 2 are designated by the same reference numerals, and the explanation will focus on the differences.

In the refrigerator of this embodiment, a buffer 15 is provided between the compression chamber 3 formed above and below the compression piston 2 and the compression chamber back pressure section 11.
A one-way valve 1 is provided between the compression chamber 3 and the buffer 15 to allow fluid to flow only in the direction from the compression chamber 3 to the buffer 15.
2 and a stop valve 13 are connected in series, and the buffer 15 and the compression chamber back pressure section 11 are connected through a pipe line provided with a stop valve 14. The other configurations are similar to the conventional refrigerator described in FIG. 2.

Since the apparatus of this embodiment is constructed as described above, a reverse Stirling cycle is performed by reciprocating the compression piston 2 and the expansion piston 8 with a predetermined phase difference, and the cold head 17 is cooled to a cryogenic temperature. What can be obtained is as mentioned above, as the working gas gradually becomes lower in temperature during the cooling process, the pressure in the refrigeration circuit gradually decreases.During this period, the pressure difference with the compressor back pressure section The gas is replenished into the refrigeration circuit through the one-way valve 16. When the cold rad 17 reaches a predetermined temperature and becomes steady, the pressure in the refrigeration circuit no longer decreases, and the one-way valve 16
The amount of working gas in the refrigeration circuit remains constant since replenishment from the refrigeration circuit also stops.

In conventional refrigerators, it was not possible to change the refrigeration performance such as the reached temperature after this, but in the refrigerator of this embodiment according to the present invention, as will be described later, the pressure in the refrigeration circuit can be made variable. This makes it possible to control refrigeration performance.

That is, during steady operation, when the stop valves 13 and 14 are opened from the closed state, compressed high-pressure working gas passes through the one-way valve 12 and is stored in the buffer 15. As a result, the pressure of the working gas in the refrigeration circuit decreases, the temperature reached by the cold head increases, and refrigeration performance can be suppressed. By adjusting the amount of working gas stored in the buffer 15, the temperature reached by the cold head 17 can be arbitrarily controlled.

When the stop valve 13 is closed and the stop valve 14 is opened, the working gas in the buffer 15 is transferred to the compression chamber back pressure section 11 which is the low pressure side.
As the pressure in the compression chamber back pressure section 11 rises above the lowest cycle pressure, the working gas therein passes through the one-way valve 16 and enters the refrigeration circuit again, reducing the amount of gas in the refrigeration circuit to its original level. The temperature reached by the cold head 17 decreases, and the refrigeration performance increases.

Therefore, depending on the load fluctuation, the working gas is
Parts in the refrigeration circuit, such as the seal ring 9.10, are stored in the refrigeration circuit and the pressure in the refrigeration circuit is lowered.
It is possible to improve the durability of

For example, when the above-mentioned refrigerator is used as a cryopump, it is sufficient if the temperature of the cold head 17 is 20 degrees, but in many cases the temperature is lower than that, for example, about 14 degrees. At such times, the working gas is transferred to buffer 1.
5, it is possible to improve the life of the cryopump while maintaining the required performance of the cryopump. This will be explained using the flowchart in FIG. When TI is about 14 and T2 is about 17, when the temperature of the cold head 17 is below T1, the stop valve 1
3 is opened and the stop valve 14 is closed, the gas pressure in the working space is lowered, and the temperature of the cold head 17 is first returned to T1. When the temperature reaches TI, the stop valve 13 is closed, the working gas pressure is lowered, and the temperature of the cold head 17 is lowered to 1.
Make it 2 or more.

After confirming that the temperature is 12 or above, the stop valve 14 is opened, the pressure in the compression chamber back pressure section 11 is increased, and the lowest cycle pressure is increased via the one-way valve 16. Temperature T1 of Coldherad 17
Keep the stop valve 14 open until the following is confirmed. When it is confirmed that the temperature is below TI, the stop valve 14 is closed and the above-described operation is repeated.

Although the present invention has been described above using an example of an embodiment in which the present invention is applied to a reverse Stirling cycle refrigerator, the present invention is not limited to refrigerators, but is applicable to other devices that utilize a reverse Stirling cycle.

(Effects) As described above, according to the present invention, it is possible to easily control the performance of a device using a reverse Stirling cycle according to load fluctuations and usage conditions, and to lower the pressure of the working fluid to the necessary limit. By doing so, it is possible to improve the life of parts and save power consumption.

[Brief explanation of the drawing]

Fig. 1 is a sectional view of an embodiment in which the present invention is applied to a reverse Stirling cycle refrigerator, Fig. 2 is a sectional view of a conventional device corresponding thereto, and Fig. 3 is a flowchart showing temperature control in an example of the present invention. It is a diagram. 1-compression cylinder, 2-compression piston, 3-compression chamber, 6-expansion chamber, 7-expansion cylinder,
8-expansion piston, 11-compression chamber back pressure section, 12.
16----One-way valve, 13.14・-Stop valve, 15-
buffer.

Claims (2)

[Claims] (1) A reverse Stirling cycle in which a piston is driven reciprocally within a cylinder to compress and expand fluid, and a compression chamber and a compression chamber back pressure section are formed on the side in the reciprocating direction of the compression piston within the cylinder. In the device, a buffer provided between the compression chamber and the compression chamber back pressure section, and a one-way valve and stop that connect the compression chamber and the buffer and allow fluid to flow only in the direction from the compression chamber to the buffer. A pipe provided with a valve, a pipe connected between the buffer and the compression chamber back pressure section and provided with a stop valve, and a pipe connected between the compression chamber back pressure section and the compression chamber and connected from the compression chamber back pressure section to the compression chamber. 1. A reverse Stirling cycle device comprising: a conduit provided with a one-way valve that allows fluid to flow only in a direction toward the stop valve; and a control means for controlling the two stop valves according to a control target value. (2) The device according to claim 1, wherein the reverse Stirling cycle device is a refrigerator, and the target value of the control is a desired take-out temperature.