JPH11200950A - Gas compression expander - Google Patents

Abstract

PROBLEM TO BE SOLVED: To surely prevent a working mixed gas in an operating chamber from leaking into a driving chamber, and also to suppress the lowering of its refrigerating capacity by installing a rod sealing device and a gas sealing device as a sealing means of a rod extending as piercing through a partitioning member, and interposing an intermediate chamber communicating to the driving chamber, between both these sealing devices. SOLUTION: A Stirling refrigerating unit as a gas compression expander is provided with an operating chamber fitted with a compression piston (or a displacer) 7 connected to one end of a piston rod (hereinafter referred to as a rod) 22. In addition, a piston driving mechanism fitted in a driving chamber 12 is connected to the other end of the rod 22, therefore this compression piston 7 is reciprocated by this driving mechanism. Here a rod sealing device 93 preventing any lubricating oil in the driving chamber 12 from penetrating into the operating chamber 21 and a gas sealing device 94 preventing any working mixture in this operating chamber 21 from penetrating into an intermediate chamber 91 both are installed in a partition part 9 partitioning off the operating chamber 21 and the driving chamber 12 where the rod 22 is pierced through, and then the intermediate chamber 91 is interconnected to the driving chamber 12 via a filter 97.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a gas compression / expansion machine such as a Stirling engine used for generating power and a Stirling refrigerator used for generating low temperature, and more particularly, to preventing lubricating oil from entering a working space. The present invention relates to a gas compression / expansion machine equipped with a rod seal device.

[0002]

2. Description of the Related Art In recent years, there has been an urgent need to develop techniques for preserving various samples and various materials at extremely low temperatures in advanced technology fields such as the field of biotechnology and the field of electronic devices. In particular, gas compression / expansion machines such as Stirling refrigerators are attracting attention as means for achieving the extremely low temperatures, and are about to be widely used in various infrared sensors, freezers for cooling and biomedical devices such as superconducting devices, and freezers.

[0003] In this gas compression and expansion machine,
A piston or a displacer for compressing and / or expanding the working gas is configured to reciprocate in the cylinder via a rod, and the rod prevents the lubricating oil from entering the working chamber from the driving chamber. A rod seal device is provided to prevent this.

FIG. 3 shows a conventional rod seal device attached to a piston rod. In the figure, 101 indicates a cylinder such as an expansion cylinder or a compression cylinder, 102 indicates a piston that reciprocates in the cylinder 101, 103 indicates a piston rod, 104 indicates a cross guide, and 1
Reference numeral 05 denotes a connecting rod connecting the cross guide 104 to a crankshaft accommodated in a crank chamber (not shown).
Reference numeral 06 denotes a guide unit for guiding the cross guide 104. At the upper end of the guide portion 106, a rod seal portion 107 that surrounds the piston rod 103 and that prevents lubricating oil in the crank chamber from entering the rear side of the piston 102 is mounted.

[0005] As the rod seal portion 107, a lip-type seal member is used which has a higher sealing property against a flow in the direction from the crank chamber to the back side of the piston 102 than a reverse flow. . This lip-type seal member is superior in one-way sealability as compared with a resin-type seal member such as a slipper seal having no seal directionality, and is widely used in hydraulic mechanisms and the like.

Further, in order to enhance the oil sealing effect of the rod seal portion 107, Japanese Patent Application Laid-Open No. 64-8785 has been disclosed.
No. 4, the rod seal portion 107 is shown in FIG.
A second seal portion 109 having a sealing property opposite to that of
The space 108 is provided on the back space side of the piston 102 via the space 108, and the space 108 is always kept at the minimum pressure of the space behind the piston 102. Thus, the pressure in the crankcase space is always higher than the pressure in the space 108, and the rod seal 107 can exhibit excellent sealing performance.

[0007]

On the other hand, the applicant has found that in the case of a lip-type sealing member having a directional sealing property, it has a gas feeding action for a flow in a direction in which the sealing property is low. Confirmed by experiment.

Therefore, in the case of the above-mentioned conventional device,
The pressure in the space 108 gradually decreases from the lowest pressure in the space behind the piston 102 due to the gas feeding action. When the pressure difference between the crankcase and the space 108 becomes considerably large as a result of the continuous operation, the rod seal portion 107 is greatly worn due to the influence of the pressure difference. As a result, the lubrication from the crankcase to the space 108 is performed. There is a risk that oil may enter and the lubricating oil may enter the working chamber on the back side of the piston 102.

Further, as a result of the continuous operation, if the pressure difference between the maximum pressure in the space behind the piston 102 and the pressure in the space 108 becomes considerably large, the piston 1
02, the working gas in the space on the back side gradually leaks to the crank chamber side through the space 108, and there is a possibility that the refrigerating capacity of the apparatus may be reduced.

The present invention has been made in view of the above points, and as a rod sealing device, the sealing performance against a flow in a direction from a driving chamber to a working chamber is higher than the sealing performance against a reverse flow. In a gas compression / expansion machine equipped with a seal member, the wear of the seal member is suppressed as much as possible to extend the life of the device, and the leakage of working gas in the working chamber to the drive room is suppressed as much as possible, so that the refrigeration capacity of the device is reduced. The purpose is to prevent the drop.

[0011]

According to the present invention, there is provided a working chamber for accommodating a piston or displacer connected to one end of a rod so as to reciprocate in a cylinder, and the other end of the rod is connected to the working chamber. In a gas compression / expansion machine having a drive chamber accommodating a piston drive mechanism for reciprocating a displacer, and a partition through which the rod penetrates to partition the working chamber and the drive chamber, A rod seal for preventing the lubricating oil in the driving chamber from entering the working chamber, comprising a sealing member having a higher sealing property against a flow in a direction from the driving chamber to the working chamber than a sealing property against the reverse flow. And an intermediate portion provided on the working chamber side of the rod sealing device and having a dimension in a rod radial direction larger than a thickness of lubricating oil adhered to the rod. A gas sealing device provided on the working chamber side of the intermediate chamber and configured to prevent a working gas in the working chamber from entering the intermediate chamber; and a lubricating oil removing member for connecting the intermediate chamber and the driving chamber to each other. And a switching means provided in the middle of the communication means and allowing movement of the working gas when the pressure difference between the intermediate chamber and the driving chamber is equal to or greater than a predetermined value. Features.

By using this configuration, the pressure drop in the intermediate chamber is suppressed, and the lubricating oil and water from the drive chamber are utilized by utilizing the gas feeding action from the intermediate chamber toward the drive chamber by the seal member of the rod seal device. Can be prevented. In addition, since the movement of the working gas is permitted when the pressure difference between the intermediate chamber and the driving chamber is equal to or more than a certain value by the opening / closing means, oil vapor or the like from the driving chamber that is not removed by the lubricating oil removing member is removed. It is possible to suppress the intrusion into the drive chamber and to maintain the pressure in the drive chamber higher than the pressure in the intermediate chamber, so that the sealing effect of the seal member can be sufficiently exhibited.

[0013] Preferably, the seal member of the rod seal device may be constituted by a lip-type seal member. By using this configuration, it is possible to achieve high sealing performance against the flow in the direction from the driving chamber to the working chamber.

Further, the seal member of the gas seal device is preferably constituted by a seal member having no directivity in the sealing property. Further, the opening / closing means is constituted by a differential pressure valve, and when the pressure difference between the intermediate chamber and the driving chamber is equal to or more than a predetermined value, movement of the working gas is allowed.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below in detail with reference to the drawings. FIG. 1 shows a gas compression / expansion machine according to one embodiment of the present invention. In the description of the present embodiment, a case of a displacer type Stirling refrigerating apparatus as a gas compression and expansion machine will be described as an example.

An expansion cylinder 2 and a compression cylinder 3 are attached to the main body housing 1 at an angle difference of 90 degrees. A displacer 6 built in the expansion cylinder 2 and a compression piston 7 built in the compression cylinder 3 are: Connected to a common crank mechanism (piston drive mechanism) 5
Reciprocating drive is performed with the phase shifted by 0 degrees.

The displacer 6 is filled with a regenerator 14 made of, for example, a sintered metal, and the working gas flowing from one opening of the displacer 6 is filled with the regenerator 14.
In the process of passing through the inside of the
Heat exchange with the cold storage material 14 is performed.

The displacer 6 also has a function as a regenerative heat exchanger, and its heat exchange performance greatly affects the coefficient of performance of the refrigeration system. Further, the expansion cylinder 2 and the compression cylinder 3 are separated from the crank chamber (drive chamber) 12 by partitions 8 and 9 described later, respectively, and the base end of the expansion cylinder 2 and the compression space of the compression cylinder 3 are The gas channels 4 communicate with each other. Thereby, the compression space 13 formed in the compression cylinder 3 and the expansion space 11 formed in the expansion cylinder 2
The gas is communicated with the gas flow path 4 via the cold storage material 14. On the other hand, the lubricating oil 10 is injected into the crank chamber 12.

With the above arrangement, the compression piston 7 and the displacer 6 reciprocate with a certain phase difference by the crank mechanism 5 driven by the rotation of the drive motor. First, the compression piston 7 moves to compress the working gas such as helium filling the inside of the apparatus main body, and the compressed and heated working gas is radiated by the radiation fins (not shown).
Next, after the working gas is cooled by the lowering of the displacer 6, the expansion space 1 serving as the working space of the expansion cylinder 2 is cooled.
It is led to 1. Thereafter, an expansion step is performed in which the working gas in the apparatus main body expands due to the movement of the compression piston 7, and the working gas is cooled to a low temperature by the expansion of the working gas, thereby cooling a cooler (not shown) via the cold head 15. Subsequently, the working gas is warmed by the rise of the displacer 6, and then the compression space 13 which is the working space of the compression cylinder 3 is heated.
Led to.

The above steps are sequentially repeated to cool the cooler when the working gas in the expansion space 11 expands, and gradually bring the temperature to the freezing temperature. Next, the structure of the above-described partitions 8, 9 will be described with reference to FIG. FIG. 2 is a cross-sectional view of a main part showing a partition 9 in the Stirling refrigerating apparatus described above. Although only the specific configuration of the partition 9 shown in FIG. 1 will be described below in detail, the same applies to the specific configuration of the partition 8.

In the drawing, reference numeral 21 denotes a working chamber having the above-mentioned compression piston 7, 22 denotes a piston rod having one end connected to the compression piston 7, 23 denotes a cross guide connected to the other end of the piston rod 22, and 24 denotes a crank. A connecting rod 25 connected to the crankshaft accommodated in the chamber 12 indicates a guide portion for guiding the cross guide 23. Further, inside the partition portion 9 located at the upper end portion of the guide portion 25, an intermediate chamber 91 provided so as to include the piston rod 22, and a space between the intermediate chamber 91 and the cross guide space of the crank chamber 12 are provided. A rod sealing device 93 provided on a partition wall 92 and a partition wall 94 between the intermediate chamber 91 and the working chamber 21.
And a communication pipe 96 that communicates the intermediate chamber 91 with the crank chamber 12.

The intermediate chamber 91 has the piston rod 2
2 is provided so that the radial dimension thereof is larger than the thickness of the lubricating oil attached to the rod 22. This is because the rod 2
The oil film of the lubricating oil that has adhered to the working chamber 2 due to the capillary phenomenon
Prevents intrusion into one side.

The rod sealing device 93 is provided for the crank chamber 12.
The lip seal has an oil seal member having a higher sealing property against the flow in the direction from the flow to the working chamber 21 than the reverse flow.

The gas seal device 95 is a T-ring type gas seal member having a non-directional sealing property for preventing the working gas in the working chamber 21 from flowing out to the crank chamber 12 through the intermediate chamber 91. It is configured.

An oil filter 9 as a lubricating oil removing member for removing lubricating oil is provided in the middle of the communication pipe 96.
7, and a differential pressure valve 98 as an opening / closing means that allows movement of the working gas when the differential pressure between the intermediate chamber 91 and the crank chamber 12 is equal to or more than a fixed value (2 atm in this embodiment). ing.

With this configuration, when the pressure in the intermediate chamber 91 becomes higher than the pressure in the crank chamber 12 by 2 atm or more, the intermediate chamber 91 and the crank chamber 12 communicate with each other through the communication pipe 96. State.

For this reason, the pressure in the intermediate chamber 91 is always maintained at a pressure within a certain range higher than the pressure in the crank chamber 12, and the sealing effect of the oil seal member 93 of the lip type seal is sufficiently exhibited. In addition to the above, there is no fear that the pressure in the intermediate chamber 91 is extremely reduced as compared with the pressure in the crank chamber 12 due to the gas feeding action of the oil seal member 93. Then, the pressure difference between the maximum pressure in the working chamber 21 and the pressure in the intermediate chamber 91 becomes very large, and the working gas in the working chamber 21 gradually cranks through the intermediate chamber 91 due to the influence of this pressure difference. There is no danger of leaking into the chamber 12 and causing a decrease in the refrigeration capacity of the apparatus.

The oil filter 97 is provided only when the pressure difference between the intermediate chamber 91 and the crank chamber 12 is equal to or higher than a predetermined value.
It is possible to suppress oil vapors and the like from the crank chamber 12 that have not been removed in the intermediate chamber 91 from entering as much as possible.

Further, the gas can be supplied from the intermediate chamber 91 to the crank chamber 12 by the gas feeding action of the oil seal member 93, and lubricating oil and moisture from the crank chamber 12 are reciprocated by the piston rod 22 so that the oil seal It is prevented from being fed through the member 93 and also has a function of returning oil vapor or the like that has entered the intermediate chamber 91 to the crank chamber 12 by a gas feeding action.

The description of the above embodiment is for the purpose of illustrating the present invention, and should not be construed as limiting the invention described in the claims or reducing the scope thereof.
Further, the configuration of each part of the present invention is not limited to the above embodiment, and various modifications can be made within the technical scope described in the claims. For example, the case where the gas seal device 95 is configured by a T-ring type gas seal member has been described. However, the present invention is not limited to this, and any seal member having no directionality in the sealing property may be used. It may be a member.

The case where a differential pressure valve is used as the opening / closing means 98 has been described. In addition, the pressure in the intermediate chamber 91 is compared with the pressure in the drive chamber 12 by using an electric valve, a one-way valve, or the like. A configuration may be employed in which control is performed so as to allow the movement of the working gas when the value becomes higher than a certain value.

[0032]

As described above, according to the present invention, as a rod seal device for preventing the lubricating oil from entering the working space, its sealing property against the flow from the driving chamber to the working chamber is improved. In a gas compression / expansion machine equipped with a sealing member having higher sealing performance against reverse flow, the wear of the sealing member is suppressed as much as possible to extend the life of the device, and lubricating oil and the like in the driving chamber are transferred to the working chamber for a long period of time. Intrusion can be reliably prevented, and leakage of the working gas in the working chamber to the drive chamber can be suppressed as much as possible, thereby preventing the refrigeration capacity of the apparatus from being reduced.

[Brief description of the drawings]

FIG. 1 is a schematic sectional view of a displacer type Stirling refrigerating apparatus to which the present invention is applied.

FIG. 2 is a cross-sectional view of a main part in the vicinity of a rod seal device according to an embodiment of the present invention.

FIG. 3 is a sectional view of a conventional rod seal device.

4 is a sectional view of a conventional rod seal device in which a part of the device of FIG. 3 is improved.

[Explanation of symbols]

 Reference Signs List 2 expansion cylinder 3 compression cylinder 4 gas flow path 5 crank mechanism (piston drive mechanism) 6 displacer 7 compression piston 8, 9 partition 11 expansion space 12 crank chamber (drive chamber) 13 compression space 21 working chamber 22 piston rod 23 cross guide 24 Connecting rod 91 Intermediate chamber 92, 94 Partition wall 93 Rod seal device 95 Gas seal device 96 Communication pipe 97 Oil filter (lubricating oil removing member) 98 Differential pressure valve (opening / closing means)

Claims (4)

[Claims] 1. A working chamber for accommodating a piston or displacer connected to one end of a rod so as to reciprocate in a cylinder, and a piston drive mechanism connected to the other end of the rod for reciprocating the piston or displacer. And a partition penetrating the rod and partitioning the working chamber and the drive chamber, wherein the partition heads from the drive chamber to the working chamber. A rod seal device for preventing the lubricating oil in the drive chamber from entering the working chamber; An intermediate chamber provided on the working chamber side and having a dimension in a rod radial direction larger than a thickness of lubricating oil attached to the rod; A gas sealing device provided on the chamber side and comprising a seal member for preventing the working gas in the working chamber from entering the intermediate chamber; and a communicating means for communicating the intermediate chamber and the driving chamber via a lubricant removing member. A gas compression / expansion device provided in the middle of the communication means, wherein the opening / closing means allows movement of the working gas when the pressure difference between the intermediate chamber and the driving chamber is equal to or more than a predetermined value. 2. The sealing member of the rod sealing device,
2. A lip-type sealing member.
Or the gas compression-expansion machine according to 2. 3. The gas compression / expansion machine according to claim 1, wherein the sealing member of the gas sealing device is a sealing member having no directionality in sealing performance. 4. The gas compression / expansion machine according to claim 1, wherein said opening / closing means is a differential pressure valve.