JP7146539B2 - compression cylinder - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a compression cylinder, and more particularly to a compression cylinder that does not require lubrication and that does not mix lubricating oil into gas to be compressed.

Patent Literature 1 describes a cylinder that compresses gas supplied to a cylindrical cylinder tube. A cylindrical cylinder liner is arranged in the cylinder tube, and a cylindrical piston having a piston ring and a rider ring is slidably arranged in the cylinder liner. The supplied gas is compressed by the reciprocating motion of the piston. Compressed gas is delivered from the outlet.

Compression of gas, for example, boil-off gas evaporated from liquefied natural gas (~300 bar) for internal combustion engine fuel, hydrogen (~200 bar) for desulfurization plant of heavy oil, CNG fuel (~240 bar), automotive This is done for methane gas (~240 bar) and the like.

Japanese Patent Publication No. 2008-528882

By the way, cylinders are sometimes used to further pressurize pressurized gas. At present, it is necessary to supply lubricating oil to compression cylinders for high pressure above a certain limit. The reason why it is necessary to supply lubricating oil is that the resin piston rings and rider rings that constitute the piston are exposed to high heat and have a short life.

The lubricating oil supplied to the compression cylinder mixes with the pressurized gas. If lubricating oil is mixed into the pressurized gas, in the case of LNG compressors, it will lead to troubles in the LNG reliquefaction equipment that operates at cryogenic temperatures. , In CNG vehicles, it leads to troubles in engine peripheral parts.

Accordingly, an object of the present invention is to provide a compression cylinder that does not require lubrication and does not mix lubricating oil into the gas to be compressed.

Other objects of the present invention will become clear from the following description.

The above problems are solved by the following inventions.

1.
Comprising a cylinder tube, a cylinder liner arranged in the cylinder tube, and a piston slidably arranged in the cylinder liner, the gas supplied from the suction port is compressed and sent out from the discharge port. a compression cylinder,
A compression cylinder, wherein a flow path is provided in the cylinder liner, and a coolant is circulated in the flow path to cool the cylinder tube, the cylinder liner, and the piston.
2.
A compression cylinder comprising a cylinder tube and a piston slidably disposed in the cylinder tube, for compressing gas supplied from a suction port and sending the gas from a discharge port,
A compression cylinder, wherein a flow path is provided in the piston, and a cooling liquid is circulated in the flow path to cool the cylinder tube and the piston.
3.
Comprising a cylinder tube, a cylinder liner arranged in the cylinder tube, and a piston slidably arranged in the cylinder liner, the gas supplied from the suction port is compressed and sent out from the discharge port. a compression cylinder,
A compression cylinder, wherein a flow path is provided between the cylinder tube and the cylinder liner, and a coolant is circulated in the flow path to cool the cylinder tube and the piston.
4.
4. The compression cylinder according to 1, 2 or 3 above, wherein the cooling liquid is fresh water, oil, or a low-temperature cooling liquid of 0° C. or lower.
5.
5. The compression cylinder according to any one of 1 to 4 above, wherein the gas supplied from the suction port or the gas delivered from the discharge port has a pressure of 200 bar or more.

According to the present invention, it is possible to provide a compression cylinder that does not require lubrication and does not mix lubricating oil into gas to be compressed.

Sectional view showing the configuration of the compression cylinder of the present invention Longitudinal cross-sectional view showing the shape of the gasket of the compression cylinder shown in FIG. 1 (AA cross section in FIG. 1) FIG. 1 is a vertical cross-sectional view showing the shape of the cylinder liner of the compression cylinder shown in FIG. FIG. 1 is a longitudinal sectional view showing the shape of the cylinder liner of the compression cylinder shown in FIG. 1 (CC section in FIG. 1) FIG. 2 is a longitudinal sectional view showing the configuration of the piston and piston rod of the compression cylinder of the present invention; It is a figure which shows the shape of the support ring of the compression cylinder of this invention, (a) is a longitudinal cross-sectional view, (b) is a front view. Sectional drawing which shows the other example of a structure of the compression cylinder of this invention FIG. 8 is a cross-sectional view showing the shape of the cooling liquid flow path of the compression cylinder shown in FIG. 7 ; FIG. 8 is a perspective view showing the shape of the cooling liquid flow path of the compression cylinder shown in FIG. 7 ; FIG. 8 is a longitudinal sectional view showing the structure of the rod packing of the cylinder shown in FIGS. 1, 5 and 7; 1 is a schematic block diagram of a compressor constructed using the compression cylinder of the present invention; FIG.

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

[First Embodiment]
FIG. 1 is a cross-sectional view showing the configuration of the compression cylinder of the present invention.

As shown in FIG. 1, the compression cylinder 1 of this embodiment includes a cylinder tube 34, a cylinder liner 35 arranged in the cylinder tube 34, and a piston slidably arranged in the cylinder liner 35. 33, compresses the gas supplied from the suction port 63 via the suction valve 63a, and sends it out from the discharge port 64 via the discharge valve 64a.

The inside of the cylinder tube 34 is formed in a tubular shape, and a cylindrical cylinder liner 35 is fitted therein. The piston 33 is formed in a cylindrical shape that can be fitted inside the cylinder liner 35 . The piston 33 is fitted with an annular piston ring 36 and a rider ring 36a. A piston rod 37 is coaxially connected to the piston 33, and when the piston rod 37 is reciprocated by the prime mover, the piston 33 is axially reciprocated. As the piston 33 slides in the cylinder liner 35 in the axial direction of the cylinder tube 34, the gas inside the cylinder tube 34 (inside the cylinder liner 35) is compressed. Since the cylinder tube for high pressure is generally small in diameter, the piston 33 and the piston rod 37 are integrally constructed, but depending on the situation, they may be constructed separately. A rod packing 70 is provided on the outer circumference of the piston rod 37 .

Gas compression heat and sliding frictional heat between the cylinder liner 35 and the piston ring 36 and rider ring 36 a fitted to the piston 33 are generated in the cylinder tube 34 . Gas heat of compression is approximately constant regardless of pressure level. However, the sliding frictional heat between the piston ring 36 and the cylinder liner 35 increases as the pressure increases. This is because the surface pressure between the piston ring 36 and the cylinder liner 35 is the same as in the case of the lubricating type, but the coefficient of friction between the piston ring 36 and the cylinder liner 35 is because it grows. The sliding frictional heat generated by the rider ring 36a is not related to the pressure, but when oil is not supplied, the coefficient of friction between the rider ring 36a and the cylinder liner 35 increases, similar to the piston ring. If the temperature of the piston ring 36 and the rider ring 36a increases due to sliding frictional heat, and the piston ring 36 and the rider ring 36a are melted and worn, the service life of the piston ring 36 and the rider ring 36a will be shortened. By removing sliding frictional heat of the piston ring 36, the service life of the piston ring 36 and the rider ring 36a can be extended even if the piston does not need to be lubricated.

The compression cylinder 1 has a structure to positively remove sliding frictional heat of the piston ring 36 and the rider ring 36a under a high-pressure non-lubricating state, thereby prolonging the life of the piston ring 36 and the rider ring 36a. Equipped with a cooling mechanism, the sliding frictional heat is positively removed, and the temperature rise of the piston ring 36 and the rider ring 36a is suppressed.

This compression cylinder 1 is provided with a cooling mechanism for removing frictional heat, which eliminates the need to supply oil to the piston. A coolant passage 55 is formed in the inserted cylinder liner 35 to cool the inside of the cylinder liner 35 . The cylinder liner 35 is made of stainless steel or steel and has a thickness of about 15 mm, and is provided with a coolant passage 55 by machining. A rear end portion (left end in FIG. 1) of the coolant passage 55 is closed by welding a rear end portion 56 of the cylinder liner 35 .

A front end portion (right end in FIG. 1) of the cylinder tube 34 is closed by a cylinder cover 57 .

FIG. 2 is a vertical cross-sectional view (cross section taken along line AA in FIG. 1) showing the shape of the gasket of the compression cylinder shown in FIG.

Contact surfaces between the cylinder cover 57 and the cylinder liner 35 are sealed with a gasket 58 made of pure iron to prevent leakage of high-pressure gas and coolant. As shown in FIG. 2 (cross-sectional view taken along line AA in FIG. 1), the surface of the gasket 58 that contacts the cylinder cover 57 is formed with a semicircular upper cooling liquid passage 60 and a lower cooling liquid passage 61, respectively. ing.

3 is a longitudinal sectional view (sectional view taken along line BB in FIG. 1) showing the shape of the cylinder liner of the compression cylinder shown in FIG.

In the cylinder liner 35, as shown in FIG. 3 (cross-sectional view taken along line BB in FIG. 1), coolant passages 55 consisting of about 24 round holes are formed in the axial direction of the cylinder liner 35, depending on the diameter of the cylinder. ing. The round holes may be long holes, and the number of round holes need not be 24.

As also shown in FIG. 3, the cylinder tube 34 is provided with an outer peripheral flow path 40 . The outer peripheral flow path 40 communicates from one end side surface 41 to the other end side surface 42 of the cylinder tube 34 . The outer peripheral passage 40 is provided on the outer peripheral side of the cylinder liner 35 and is a normal cylinder coolant passage provided in a high-pressure cylinder in the form of a plurality of through pipes. A cooling liquid is caused to flow in the outer peripheral channel 40 . After flowing through the outer peripheral channel 40 from the side surface 41 , the cooling liquid flows out from the side surface 42 .

By cooling the cylinder liner 35, the coolant flowing through the outer peripheral flow path 40 absorbs the heat of the piston ring 36 and the rider ring 36a, and radiates the heat outside the cylinder cylinder 34, thereby lowering the temperature of the rings. do.

4 is a longitudinal sectional view (CC section in FIG. 1) showing the shape of the cylinder liner of the compression cylinder shown in FIG.

The sliding surfaces of the cylinder liner 35 with the piston ring 36 and the rider ring 36a are thermally sprayed with nitride or tungsten carbide to prevent the piston ring 36, the rider ring 36a and the cylinder liner 35 from wearing. The cylinder cover 57 is equipped with an O-ring 59 for gas sealing at the insertion portion into the cylinder cylinder 34 . As shown in FIG. 4 (CC cross-sectional view in FIG. 1), a cooling liquid communication passage 62 is provided in the cylinder liner 35 on the base end side (left side in FIG. 1) of the cylinder liner 35, extending almost all around. formed.

The coolant is supplied from the lower coolant passage 61a on the lower side of the cylinder cover 57 in FIG. The cooling liquid enters the lower half of the cylinder liner 35 from the lower cooling liquid passage 61 through a through hole formed in the gasket 58 . The coolant that has entered the cylinder liner 35 flows through the cylinder liner 35 toward the base end side (left side in FIG. 1). After passing through the lower half of the cylinder liner 35 , the coolant changes direction at the base end side of the cylinder liner 35 and moves to the upper half of the cylinder liner 35 through the coolant communication passage 62 . The coolant that has moved to the upper half of the cylinder liner 35 flows to the tip side (right side in FIG. 1) and finally returns to the coolant supply device through the upper coolant passage 60a in the upper half of the cylinder cover 57.

As the coolant, fresh water having a cooling temperature corresponding to the compression pressure is generally used, but if necessary, a low-temperature coolant of 0° C. or less, such as an ethylene glycol aqueous solution, can be used to increase the cooling effect. There is also the possibility of oil cooling, although the cooling effect is somewhat inferior.

The cooling liquid circulating in the cooling liquid passage 55 absorbs heat from the piston 33, the piston ring 36, the rider ring 36a, the cylinder tube 34, and the cylinder liner 35, and dissipates the heat outside the cylinder tube 34. Cool inside. By providing such a cooling mechanism, the compression cylinder 1 does not require lubrication. In this compression cylinder 1, the piston ring 36 and rider ring 36a are kept in a temperature state comparable to that of the low-pressure non-lubricating cylinder, so that the life of the piston ring 36 and rider ring 36a is extended.

The temperature of the piston ring 36 and the rider ring 36a can secure a heat transfer area to the extent that frictional heat can be substantially removed by a cooling mechanism. Therefore, even in the case of the lubrication type, almost the same gas compression heat remains, so that the gas can be pressurized to a high pressure without lubrication.

In a compressor using this compression cylinder 1, since the piston does not need to be lubricated at all compression stages, the gas is not contaminated with impurities, and the unused gas can be returned to the storage tank. Alternatively, all of the gas that has been circulated within each compression stage can be finally returned to the storage tank.

This cooling mechanism provides a more reliable fit between the cylinder tube 34 and the cylinder liner 35 than the later-described embodiment (FIGS. 7 to 9) that cools the outer peripheral side of the cylinder liner 35 .

[Second embodiment]
FIG. 5 is a vertical cross-sectional view showing the configuration of the piston and piston rod of the compression cylinder of the present invention.

In the compression cylinder 1 of this embodiment, instead of or in addition to the cooling mechanism shown in FIGS. 1 to 4, as shown in FIG. Cool by circulating the liquid. The flow path 43 is formed along the axial direction of the piston rod 37 from the distal end side to the proximal end side of the piston 33 and the piston rod 37 . The interior of the flow path 43 is partitioned into a central portion 43 a and an outer peripheral portion 43 b by a cylindrical body 44 arranged in the flow path 43 . A support ring 45 is fitted between the tip side portion of the cylindrical body 44 and the inner wall portion of the flow path 43 . Since the high-pressure cylinder tube is generally small in diameter, the piston 33 and the piston rod 37 are integrally constructed, but in some cases they may be constructed separately.

6A and 6B are views showing the shape of the support ring of the compression cylinder of the present invention, where (a) is a longitudinal sectional view and (b) is a front view.

As shown in FIGS. 5 and 6, the support ring 45 is axially formed with a plurality of through holes 49 through which the coolant flows.

Coolant flows through a coolant flow path 48 from a coolant inlet 47 provided in the cylinder tube 34 into the flow path 43 in the piston rod 37 . The cooling liquid that has passed through the cooling liquid flow path (flexible tube) 48 flows through the cooling liquid inlet 46 provided on the proximal end side of the piston rod 37 and into the central portion 43 a in the cylindrical body 44 . The cooling liquid in the central portion 43a flows toward the tip side of the piston rod 37, passes through a plurality of through holes 44a provided on the tip side of the cylindrical body 44, and reaches the outer peripheral portion 43b. The coolant in the outer peripheral portion 43 b flows through the insertion hole 49 of the support ring 45 toward the base end side of the piston rod 37 . The coolant on the proximal side of the piston rod 37 flows out of the piston rod 37 through a coolant outlet 50 provided on the proximal side of the piston rod 37 . The coolant that has flowed out from the piston rod 37 passes through a coolant flow path (flexible pipe) 52 provided in the cylinder cylinder 34 and flows out from a coolant outlet 51 .

One end of the cylindrical body 44 is fixed in a guide hole provided in the piston rod 37, and the other end of the cylindrical body 44 is fixed in a guide hole provided in the piston cover 65. I try not to. If the inner diameter dimension of the support ring 45 is adjusted with respect to the outer diameter dimension of the cylindrical body 44, the vibration of the cylindrical body 44 can be prevented.

The cooling liquid circulating in the piston rod 37 absorbs heat from the piston 33, the piston rings 36, the rider ring 36a, the cylinder tube 34, and the cylinder liner 35, and radiates the heat outside the cylinder tube 34, so that the piston rings 36, Cool the rider ring 36a. By providing such a cooling mechanism, the compression cylinder 1 does not require lubrication.

The temperature of the piston ring 36 and the rider ring 36a can secure a heat transfer area to the extent that frictional heat can be substantially removed by a cooling mechanism. Therefore, even in the case of the lubrication type, almost the same gas compression heat remains, so that the gas can be pressurized to a high pressure without lubrication.

A rod packing 70 is provided on the outer periphery of the piston rod 37 as shown in FIG.

[Third Embodiment]
FIG. 7 is a cross-sectional view showing another example of the configuration of the compression cylinder of the present invention.

In the compression cylinder 1 of this embodiment, instead of the cooling mechanism shown in FIGS. 1 to 4, or in addition to the cooling mechanism shown in FIGS. 5 to 6, as shown in FIG. The piston ring 36 and the rider ring 36a may be cooled by circulating coolant between the liners 35 . The outer periphery of the cylinder liner 35 has a plurality of annular grooves 38 with a semicircular cross-section in order to circulate the cooling liquid to achieve uniform cooling and to increase the cooling area to increase the cooling effect. O-rings 41a and 41b are inserted in front of and behind the annular groove 38 to prevent leakage of the coolant, and the fitting margin and the O-rings 41a and 41b prevent the high-pressure gas from leaking to the coolant side.

8 is a cross-sectional view showing the shape of the cooling liquid flow path of the compression cylinder shown in FIG. 7. FIG.
9 is a perspective view showing the shape of the cooling liquid flow path of the compression cylinder shown in FIG. 7. FIG.

As shown in FIG. 8, the cooling liquid is supplied from the outer cooling liquid passage 42a on the side surface 41 of the cylinder cylinder 34, flows through the annular groove 38 on the back surface of the cylinder liner 35 as shown in FIG. Friction sliding heat between the piston ring 36 and the cylinder liner 35 and between the rider ring 36a and the cylinder liner 35 is generated by the cooling circuit discharged from the outer coolant passage 42b of the other side surface 42 of the cylinder cylinder 34 and returned to the coolant recovery line. and the heat of gas compression in the cylinder is effectively removed in the immediate vicinity of its heat source. As shown in FIG. 9 , the annular groove 38 communicates with the cylinder tube 34 from one end side to the other end side via a communication passage 39 .

The cylinder tube 34 is provided with an outer peripheral passage 40 as shown in FIG. The outer peripheral flow path 40 communicates from one end side surface 41 to the other end side surface 42 of the cylinder tube 34 . The outer peripheral passage 40 is a normal cylinder cooling liquid passage provided in the high-pressure cylinder in the shape of a plurality of straight pipes which are provided on the outer peripheral side of the cylinder liner 35 and positioned outside the annular groove 38 . Together with this, the annular groove 38 aims at increasing the cooling effect of the cylinder tube 34 .

Coolant is circulated in the annular groove 38 and in the outer peripheral channel 40 . As shown in FIG. 8, the annular groove 38 communicates with the outer coolant passage 42a of the side surface 41. As shown in FIG. Also, the annular groove 38 is communicated with the outer coolant passage 42b of the side surface 42 . The coolant flows into the annular groove 38 from the side surface 41 , circulates in the annular groove 38 and the outer peripheral channel 40 , and then flows out from the side surface 42 .

The cooling liquid circulating in the annular groove 38 and the outer peripheral passage 40 cools the cylinder liner 35, absorbs the heat of the piston ring 36 and the rider ring 36a, and radiates the heat outside the cylinder tube 34. The ring temperature can be lowered to extend the ring life. By providing such a cooling mechanism, the compression cylinder 1 does not require lubrication.

The heat transfer area of the inner wall of the annular groove 38 varies depending on the cylinder cylinder diameter and cylinder cylinder length, and also depends on the coolant used, but the temperature of the piston ring 36 and the rider ring 36a is substantially removed by the cooling mechanism. A possible heat transfer area can be secured. Therefore, even in the case of the lubrication type, almost the same gas compression heat remains, so that the gas can be pressurized to a high pressure without lubrication.

[Structure of rod packing]
10 is a longitudinal sectional view showing the structure of the rod packing of the cylinder shown in FIGS. 1, 5 and 7. FIG.

As shown in FIG. 10, the rod packing 70 comprises a plurality of rod packing rings 53 supporting the outer periphery of the piston rod 37 and a plurality of ring cups 54 accommodating the rod packing rings 53. there is Sliding frictional heat is also generated by sliding between the rod packing ring 53 and the piston rod 37 . This sliding frictional heat is transmitted to the ring cup 54 housing the rod packing ring 53 .

The rod packing 70 distributes and supplies cooling liquid (clean water or oil) to the flow paths in each ring cup 54 from the cooling liquid supply path 66 communicating with the outside at the cooling liquid supply port 68, and the cooling liquid is supplied from these flow paths. may be provided with a cooling mechanism of a direct cooling system that collects and discharges the coolant in the coolant discharge passage 67 communicating with the outside at the coolant discharge port 69 . Furthermore, by increasing the cooling effect, such as using a low-temperature coolant (e.g., low-temperature ethylene glycol aqueous solution), bringing the coolant channel closer to the ring as much as possible, and increasing the coolant channel area, a large amount of sliding friction can be achieved. Heat can be removed.

[Compressor configuration example]
FIG. 11 is a block diagram schematically showing a compressor constructed using the compression cylinder of the present invention (showing an example in which lubrication is not required due to reliquefaction).

The compressor 100 configured using the compression cylinder 1 of the present invention may have one stage, but as an example, as shown in FIG. , 102, 103, 104, and 105, and the gas is gradually compressed in each of the compression stages 101, 102, 103, 104, and 105 to increase the pressure. In the latter of the multiple compression stages 101, 102, 103, 104, 105 (eg the fourth stage) the gas is already at a high pressure of over 100 bar (10 MPa).

Conventionally, in a cylinder that further compresses a high-pressure gas of 100 bar (10 MPa) or more, there is a risk that resin seal rings (piston ring and rod packing ring) will have a short life due to high heat. Under low pressure, the resin seal ring can maintain a practical life even without lubrication. However, for example, when compressing LNG boil-off gas to use it as fuel gas for a marine engine, five-stage compression is required. Under high-pressure conditions of a bar or higher, there is a possibility that the practical life of the resin seal ring cannot be maintained in the non-lubricating type.

The compression cylinder 1 of the present invention is equipped with a cooling mechanism, and by circulating the cooling liquid in the flow path to cool the piston, when it is used in any of the compression stages 101, 102, 103, 104, and 105, refueling is unnecessary.

Therefore, in this compressor 2, there is no risk that the compressed gas will be contaminated with lubricating oil. Therefore, it becomes possible to re-liquefy and reuse the gas that has passed through the subsequent compression stage at extremely low temperatures and high pressures. This compressor 2 can be applied to any application, for example, in the application of compressing natural gas, it is possible to return the natural gas after the final compression stage 105 to the storage tank 106 . Also, the check valve before the subsequent compression stage (between the fourth stage 104 and the fifth stage 105), which is essential in the conventional compressor, is no longer required.

In addition, high-pressure hydrogen gas used for heavy oil desulfurization cannot be used without oil because of its high pressure, so it is used while containing oil. This shortens the life of the expensive catalyst in the reactor, but at present there is no way to deal with it, so high-pressure hydrogen gas containing oil is used. If this becomes high-pressure hydrogen gas that does not contain oil, the service life of the catalyst can be extended, which is a great advantage.

The present invention is not limited to the above-described embodiments, and various improvements and design changes may be made without departing from the scope of the present invention. For example, the cooling mechanism described above may have each configuration of the first to third embodiments independently, or may have a plurality of configurations.

In addition, it goes without saying that the specific detailed structure, numerical values, etc., and the control content of the control device, etc., can also be changed as appropriate. In addition, the embodiments disclosed this time should be considered in all respects to be illustrative and not restrictive. The scope of the present invention is indicated by the scope of the claims rather than the above description, and is intended to include all modifications within the scope and meaning of equivalents of the scope of the claims.

1 Compression Cylinder 33 Piston 34 Cylinder Pipe 35 Cylinder Liner 36 Piston Ring 36a Rider Ring 37 Piston Rod 38 Annular Groove 39 Communication Path 40 Peripheral Flow Path 41 Sides 41a, 41b O-ring 42 Sides 42a, 42b Outer Coolant Path 43 Flow Path 43a Central portion 43b Peripheral portion 44 Cylindrical body 45 Support ring 46 Coolant inlet 47 Coolant inlet 48 Coolant channel 49 Insertion hole 50 Coolant outlet 52 Coolant channel 51 Coolant outlet 53 Rod packing ring 54 Ring cup 55 Coolant passage 56 Rear end portion 57 Cylinder cover 58 Gasket 59 O-ring 60 Upper coolant passage 60a Upper coolant passage 61 Lower coolant passage 61a Lower coolant passage 62 Coolant communication passage 63 Suction port 63a Suction valve 64 Discharge Outlet 64a Discharge valve 65 Piston cover 66 Coolant supply path 67 Coolant discharge path 68 Coolant supply port 69 Coolant discharge port 70 Rod packing 100 Compressor 101 First compression stage 102 Second compression stage 103 Third compression stage 104 fourth compression stage 105 fifth compression stage 106 storage tank

Claims (4)

Comprising a cylinder tube, a cylinder liner arranged in the cylinder tube, and a piston slidably arranged in the cylinder liner, the gas supplied from the suction port is compressed and sent out from the discharge port. A compression cylinder that does not require lubrication,
The discharge port is provided on one side of the cylinder tube, and the intake port is provided on the other side of the cylinder tube opposite to the discharge port,
A cooling fluid passage provided in one side of the cylinder liner and a cooling fluid passage provided in the other side of the cylinder liner to cool the inside of these cooling fluid passages. The cylinder tube, the cylinder liner and the piston are cooled by the reciprocation of the liquid from one end of the cylinder liner to the other end ,
The cooling liquid is fresh water, an ethylene glycol aqueous solution, or oil, and is supplied to the cooling liquid passage from one side of one end portion of the cylinder liner, and is supplied to the one side of the cylinder liner provided with the discharge port . It passes through the coolant passage , changes direction at the other end of the cylinder liner, passes through the coolant passage on the other side of the cylinder liner provided with the suction port , and passes through the other end of the cylinder liner. a compression cylinder, characterized in that it is discharged from said coolant passage on the side thereof . 2. A compression cylinder according to claim 1, wherein a cooling fluid passage is provided in said piston, and said cylinder cylinder and said piston are cooled by circulating cooling fluid in said cooling fluid passage . A coolant passage is provided between the cylinder tube and the cylinder liner, and the cylinder tube and the piston are cooled by circulating the coolant in the coolant passage . Item 3. A compression cylinder according to item 1 or 2. 4. A compression cylinder according to claim 1, 2 or 3 , characterized in that the gas supplied from said inlet or delivered from said outlet has a pressure of 200 bar or more.

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