JPH0250384B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to Stirling cycle refrigerators, and more particularly to Stirling cycle refrigerators having separate closed cycle circuits of working gas for output at two or more temperature levels.

A Stirling cycle refrigerator connects an expansion chamber defined by a displacement piston and a compression chamber defined by an operating piston via a water-cooled heat exchanger (high temperature side heat exchanger), a regenerator, and a low temperature side heat exchanger. The two pistons are connected to each other, and both pistons are operated with a phase difference by a crank mechanism or swash plate mechanism, and the working gas is configured to continuously undergo isothermal compression, isovolume change, isothermal expansion, and isovolume change to generate refrigeration. There is. In this type of Stirling cycle refrigerator, output is generally obtained at two or more temperature levels: a relatively high temperature level and a relatively low temperature level, and the output at the relatively high temperature level is The output at relatively low temperature levels is heat shielded.

An example of obtaining output at two temperature levels with this type of Stirling cycle refrigerator will be explained with reference to FIG.

Expansion chambers 4, 4', compression chambers 5,
5' is made in each cylinder 6, 7, and both chambers 4, 5
are connected by a closed cycle 11, 12 having a water-cooled heat exchanger 8, a regenerator 9, and a low temperature side heat exchanger 10. For example, one closed cycle 11 is brought to a temperature level of 20〓, and the other closed cycle 12 is brought to a temperature level of 77〓.
is set to

(Problem to be Solved by the Invention) Different temperature levels of this type require different regenerator capacities. In other words, as shown in the following figure, at relatively high temperatures, the specific heat of the regenerator material is equal to that of the working gas (He).
It is sufficiently large compared to the specific heat of To do this, a large amount of cold storage material is required. Therefore, the capacity of a closed cycle regenerator that outputs a relatively low temperature level is larger than the capacity of a closed cycle regenerator that outputs a relatively high temperature level. However, when increasing the regenerator capacity (increasing the amount of regenerator material) in order to improve the efficiency of the regenerator at relatively low temperature levels, the dead volume within the closed cycle increases and the pressure increases. The efficiency of the cycle decreases due to increased losses. Therefore, in order to improve the efficiency of the regenerator at relatively low temperature levels without reducing the efficiency of the cycle, the working gas volume can be reduced (lower working gas pressure and lower mass flow rate) and the relative Therefore, it is necessary to increase the amount of cold storage material, and it is necessary to set the optimal sealing pressure level for different temperature levels (high pressure on the relatively high temperature side, low pressure on the relatively low temperature side).

However, in order to reduce the size of a Stirling cycle refrigerator, which has separate closed cycle circuits for working gas in order to obtain output at two or more temperature levels, each If the pistons are operated by a common drive mechanism housed in the drive chamber, even if the initial sealing pressure is set to the optimal sealing pressure level for the different temperature levels mentioned above, the pistons may not be driven due to leakage from the sealing member, etc. The pressure of the working gas in each closed cycle becomes the same through the chamber, making it impossible to use the regenerator efficiently and resulting in poor cycle efficiency. Note that in order to maintain the optimum sealing pressure, a separate compressor or the like is required, making the configuration complicated.

To optimize the working gas filling pressure of each closed cycle to the temperature level with a simple configuration.

In order to solve the above-mentioned problems, the present invention has two
Stirling cycle refrigeration operated by a common drive mechanism in which each piston defining the closed cycle is housed in a drive chamber, each having a separate closed cycle circuit of working gas for output at more than one temperature level. In the machine, the working gas is allowed to flow from one compression chamber during the closed cycle to the other compression chamber during the closed cycle, and from the compression chamber during the one closed cycle to the compression chamber during the other closed cycle. 2 arranged in series to prevent the flow of working gas from the compression chamber during one closed cycle to the compression chamber during one closed cycle.
A Stirling cycle refrigerator is provided, which is characterized in that it is directly connected via two one-way valves.

An embodiment of the present invention will be described with reference to FIG.

By appropriately adjusting the opening pressure of the one-way valve,
Regardless of the phase difference between the two cycles (there may or may not be a phase difference), a relatively high temperature level is output from the compression chamber 5 of the closed cycle 11, which outputs a relatively low temperature level, in the closed cycle 12. Working gas can be fed into the compression chamber 5. That is, each compression piston 3, 3' of both cycles is driven, and the compression chamber 5 and both one-way valves 15, 1 of the closed cycle 11 are driven.
5' becomes equal to or higher than the opening pressure of the one-way valve 15, working gas is sent between the two one-way valves 15 and 15' from the compression chamber 5 of the closed cycle 11, and then the compression chamber of the closed cycle 12 Chamber 5' and both one-way valves 15,1
When the differential pressure between the two one-way valves 15 and 15' exceeds the opening pressure of the one-way valve 15', the working gas between the two one-way valves 15 and 15' is supplied to the compression chamber 5' of the closed cycle 12. This operation is repeated until the differential pressure no longer exceeds the opening pressure of each one-way valve, and the optimum sealing pressure is maintained.

In addition, the pressure drop in the compression chamber 5 in the closed cycle 11 is as follows:
The one-way valve 13 maintains the lowest pressure in the compression chamber 5 at the pressure in the drive chamber 14, thereby compensating for it.

[Brief explanation of drawings]

FIG. 1 is an explanatory diagram of a conventional Stirling cycle refrigerator, and FIG. 2 is an explanatory diagram of a Stirling cycle refrigerator as an example of the present invention. In the figure, 1... drive mechanism, 2, 3... piston,
4, 4'...expansion chamber, 5,5'...compression chamber, 11,
12...Closed cycle circuit, 14...Drive chamber, 15
...One-way valve, 16... Working gas circuit.

Claims (1)

[Claims] 1 Stirling having a separate closed cycle circuit of working gas for obtaining output at two or more temperature levels, each piston defining the closed cycle being actuated by a common drive mechanism housed in a drive chamber. In a cycle refrigerator, a working gas is allowed to flow from one compression chamber during a closed cycle to the other compression chamber during a closed cycle, and from the compression chamber during one closed cycle to the compression chamber during another closed cycle. , a Stirling cycle characterized by being directly connected via two one-way valves arranged in series that prevent the flow of working gas from the compression chamber during the other closed cycle to the compression chamber during the one closed cycle. refrigerator.