JPH11257222A - Multistage compressor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To facilitate the production of high pressure by improving the sealing performance of the post-stage compression part of a multistage compressor that compresses gas repeatedly to produce high pressure. SOLUTION: A reciprocating compression part 104 for final compression and a reciprocating compression part 103 for compression before that final compression use a plunger piston. The diametral clearance between a cylinder 6 and a plunger piston 54 within the reciprocating compression part 104 is made smaller than that between a cylinder 1 and a plunger piston within the reciprocating compression part 103. The cylinder 1 and the associated plunger piston are formed to keep their clearance in the range of 3 to 10 μm, and this plunger pump is formed in its surface with a plurality of labyrinth seal grooves of a ratio of depth B to width A from 0.2 to 0.5.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a compression apparatus, and more particularly to a structure of a compression apparatus suitable for filling natural gas at a high pressure into a cylinder or the like.

[0002]

2. Description of the Related Art As this type of compression apparatus, for example, as shown in FIG. 3, four reciprocating compression sections 101, 102, 103, 1 are used.
US Pat. No. 5,033,940 discloses a four-stage compressor in which the reciprocating compressor 104 is disposed so as to reciprocate on orthogonal axes 105 and 106, the pressure is sequentially increased from the reciprocating compressor 101, and the reciprocating compressor 104 is the final high-pressure compressor. It is well known.

In the four-stage compression apparatus, a pair of opposed pistons 51 and 53 are connected to a yoke 61A, and a cross slider 62A movably provided across the shaft 106 in the yoke 61A is connected via a crank pin 63. It is connected to a crankshaft 64. Further, the other pair of opposed pistons 52 and 54 are oriented 9 degrees with the yoke 61A.
The yoke 61B is connected to the yoke 61B disposed at a position shifted by 0 degrees,
A cross slider (not shown) movably provided across the shaft 105 in 1B is also connected to the crankshaft 64 via the crankpin 63.

Therefore, when the crank pin 63 is rotated around the crank shaft 64 by rotating the crank shaft 64 by an electric motor (not shown),
In the yoke 61A, the displacement of the crank pin 63 in the direction of the shaft 105 corresponds to the movement of the cross slider 62A, and the movement of the yoke 61A in the direction of the shaft 106 corresponds. It reciprocates only in the direction of the axis 106.

On the other hand, in the yoke 61B, a cross slider (not shown) moves in the direction of the shaft 106, and the yoke 61B moves in the direction of the shaft 105, so that the pair of pistons 52, 54 It reciprocates only in the direction of the axis 105.

In order to obtain a smooth reciprocating motion of the pistons 51, 52, 53, 54 from the constant speed rotation of the crankshaft 64, the cross slider 62 must slide smoothly within the yoke 61. Therefore, for example, as shown in FIG. 4, the rolling bearing 65 is interposed between the yoke 61 and the cross slider 62.

[0007] A labyrinth seal groove (not shown) is provided on the surface of the piston 54 of the reciprocating compression section 104 in the final stage.
Are used, and piston rings 51A, 52A, 53A are fitted into the pistons 51, 52, 53 of the other reciprocating compression parts, respectively, to achieve sealing between the cylinders.

[0008]

However, the above-mentioned configuration 4
By the stage compression device, for example, natural gas mainly composed of methane is supplied to a cylinder as a fuel tank of a natural gas vehicle,
When filling by compressing under pressure up to the standard of 20 MPa,
In the reciprocating compression section 103 for performing the third stage compression, it is necessary to pressurize and compress the natural gas of about _MPa to about 7 MPa by the piston 53, but the piston ring 53A of the piston 53 wears and the sealing performance in the reciprocating compression section 103 is increased. Decreases, which makes it impossible to obtain the required high pressure.
There was a problem that a required amount of natural gas could not be supplied.

That is, even if a hard and highly lubricated resin-made piston ring such as Teflon is used for the piston ring 53A in order to enhance the sealing performance, the piston 53
Reciprocates while the piston ring 53A is in contact with the cylinder 1 of the reciprocating compression section 103, so that its wear is inevitable. Therefore, as the usage time of the piston ring 53A increases, the amount of wear increases, and a gap is formed between the piston ring 53A and the cylinder 1 of the reciprocating compression unit 103, so that a required high pressure cannot be obtained. Since the pressure is high, the amount of leakage from a small gap is large, and the supply of a required amount cannot be ensured. I needed to.

[0010]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems of the prior art, the present invention comprises a plurality of compression sections each comprising a cylinder and a piston, and compresses and supplies gas by sequentially passing the compression sections. In the multi-stage compression device, a multi-stage compression device in which the final-stage compression section and the last-stage pre-stage compression section include a plunger piston,

[0011] In the multistage compression apparatus of the first configuration,
A second configuration in which the radial gap between the cylinder in the final stage compression section and the piston reciprocating in the interior thereof is smaller than the gap between the cylinder in the last stage preceding stage and the piston reciprocating in the interior thereof. A multi-stage compressor,

In the multistage compression apparatus of the first or second configuration, the diametrical gap between the cylinder of the compression section in the preceding stage of the last stage and the piston reciprocating inside the cylinder is 3 to 10 mm.
μm, a multi-stage compression device of a third configuration,

In the multistage compression apparatus according to any one of the first to third configurations, the diametrical gap between the cylinder in the final stage compression section and the piston reciprocating inside the cylinder is 2 to 8 μm.
A multi-stage compression device having a fourth configuration,

In the multistage compression apparatus of any one of the first to fourth configurations, the piston reciprocating inside the cylinder of the compression section at the front stage of the last stage has a plurality of grooves on its surface. Groove depth B ratio (B / A) is 0.2 to
A multi-stage compression device of a fifth configuration, which is set to 0.5,

In the multistage compression apparatus according to any one of the first to fifth configurations, there is provided a multistage compression apparatus according to a fifth configuration, wherein the compression section is configured with four stages.

[0016]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is an explanatory view of a reciprocating compression section 103 of a third stage in a four-stage compression apparatus 100 for natural gas according to the present invention. The natural gas sucked into the chamber 103S is compressed.

When the plunger piston 2 retreats so as to enlarge the volume of the compression chamber 103S, the compression chamber 103S of the second stage reciprocating compression section 102 is opened via the valve mechanism 3. When the plunger piston 2 moves forward so as to reduce the volume of the compression chamber 103S (hereinafter, this operation is referred to as a compression operation),
The compression chamber 1 of the fourth stage reciprocating compression section 104 via the valve mechanism 4
It communicates with 04S.

The cylinder 1 and the plunger piston 2 are formed so that the gap in the diametrical direction falls within a range of 3 to 10 μm as a whole, and the pressure in the compression chamber 103S when the plunger piston 2 performs the compression operation. The cylinder 1 and the plunger piston 2
To reduce the amount of gas leaking from the gap between
The amount of gas supplied to the compression chamber 104S of 04 is not short.

The gap in the diameter direction between the cylinder 1 and the plunger piston 2 is preferably as small as possible from the viewpoint of pressure loss and the like.
01 is 78 mm, reciprocating compression part 102 is 39 mm
mm) and a plunger piston 2
Making the gap smaller than 3 μm is disadvantageous because the manufacturing cost is increased because higher precision is required. Even if there is a gap of 3 μm or more, the fourth stage reciprocating compression unit 1
Since it is sufficiently possible to pressurize and compress to a predetermined 20 MPa by the compression in 04, the gap may be 3 μm or more.

On the other hand, even if a labyrinth seal groove 5 described later is provided on the surface of the plunger piston 2, if there is a gap larger than 10 μm between the cylinder 1 and the plunger piston 2, the gas leaking from this gap will be reduced. The compression chamber 104 of the fourth stage reciprocating compression unit 104 is too large
The amount of gas supplied to S becomes insufficient, and the gas cannot be supplied to the compression chamber 104S by being pressurized to about 7 MPa.

Therefore, the gap between the cylinder 1 and the plunger piston 2 is 3 to 1 as described above.
It is formed so as to fall within a range of 0 μm.

On the surface of the plunger piston 2, a plurality of, for example, seven labyrinth seal grooves 5 are provided at intervals of 4 mm to enhance the sealing effect.

Each labyrinth seal groove 5 has a reciprocating compression portion 1
Considering that the gas to be pressurized and compressed in the reciprocating compressor 104 is a natural gas containing methane as a main component, the depth B is 0.2 to 0.5 mm, the width A is 1.0 mm, and , And the ratio of depth B / width A is 0.2 to 0.5.

If the ratio of depth B / width A is less than 0.2, the pressure fluctuation inside the groove is small, and eddies are unlikely to be generated, so that there is a disadvantage that the sealing property is deteriorated. However, the labyrinth seal groove 5 has a depth B / width A ratio of 0.2 to 0.5. It is provided so that it may fall within the range.

On the other hand, the cylinder 6 constituting the fourth stage reciprocating compression section 104 and the reciprocating operation inside the cylinder 6 make the compression chamber 10
The gap in the diameter direction between the plunger piston 54 and the plunger piston 54 that compresses and compresses the natural gas sucked into the 4S is formed to be 2 to 8 μm in total (see FIG. 3).

The cylinder 6 and the plunger piston 5
The diameter of the gap between the cylinder 6 and the plunger piston 54 having a diameter of about 13 mm is preferably 2 μm.
Making the diameter smaller than m is disadvantageous because the manufacturing cost is increased because higher precision is required. Even if there is a gap of 2 μm or more, the natural pressure supplied from the reciprocating compression unit 103 is compressed to about 7 MPa and supplied. The gas is supplied to the specified 20MP
The gap may be 2 μm or more because the pressure can be sufficiently compressed to a.

However, if there is a gap larger than 8 μm between the cylinder 6 and the plunger piston 54, even if a labyrinth seal groove is provided on the surface of the plunger piston 54, a large amount of gas leaks from this gap. Not only does it become impossible to compress and compress natural gas to a predetermined level of about 20 MPa because of too much, and it is not possible to supply a required amount of high-pressure natural gas within a predetermined time.

Therefore, the gap between the cylinder 6 and the plunger piston 54 in the diameter direction is 2 to 2 as described above.
It is formed so as to fall within the range of 8 μm.

Also, a plurality of labyrinth seal grooves (not shown) are formed on the surface of the plunger piston 54 to enhance the sealing effect with the cylinder 6.

The gap in the diameter direction between the cylinder 6 of the fourth stage reciprocating compression section 104 and the plunger piston 54 is larger than the gap between the cylinder 1 and the plunger piston 2 of the third stage reciprocating compression section 103. The size is reduced to prevent the pressure loss and the amount of leaked gas from increasing.

The other structure is substantially the same as that of the compression device such as US Pat. No. 5,033,940 shown in FIGS.

Therefore, according to the four-stage compression apparatus of the present invention having the above configuration, the compression chamber 101 of the reciprocating compression section 101
S, compression chamber 102S of reciprocating compression section 102, reciprocating compression section 1
03 compression chamber 103S, the compression chamber 10 of the reciprocating compression section 104
When the natural gas is sequentially pressurized and compressed in 4S and charged into a fuel cylinder of a natural gas vehicle or the like, the reciprocating compression unit 1 which becomes high pressure
The amount of natural gas leaking from the gap between the cylinder and the plunger piston during pressurization and compression in the compression chamber 103S of No. 03 and the compression chamber 104S of the reciprocating compression section 104 is reduced, and a predetermined high pressure can be easily obtained. Also, the filling time can be shortened.

Since the present invention is not limited to the above embodiment, various modifications can be made without departing from the scope of the claims.

[0035]

As described above, according to the multistage compression apparatus of the present invention, gas leakage in the latter compression section that mainly obtains a predetermined high pressure can be prevented.
It is possible to quickly pressurize and supply to a high pressure such as a.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram showing a main part of one embodiment.

FIG. 2 is an explanatory diagram showing a part of FIG. 1 in an enlarged manner.

FIG. 3 is an explanatory diagram showing a structure of a four-stage compression device.

FIG. 4 is an explanatory diagram showing a drive mechanism of the four-stage compression device shown in FIG.

[Explanation of symbols]

 Reference Signs List 1 cylinder 2 plunger piston 3.4 valve mechanism 5 labyrinth seal groove 6 cylinder 51.52.53.54 piston 100 four-stage compression device 101.102.103.104 reciprocating compression section 101S, 102S, 103S, 104S compression chamber

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Makoto Ma, Inventor Sanyo Electric Co., Ltd. 2-5-2-5 Keihanhondori, Moriguchi-shi, Osaka (72) Inventor Takehiro Nishikawa 2-5-2 Keihanhondori, Moriguchi-shi, Osaka No. 5 Sanyo Electric Co., Ltd.

Claims (6)

[Claims] 1. A multi-stage compression apparatus comprising a plurality of compression sections each comprising a cylinder and a piston, and supplying a gas by compressing the gas by sequentially passing through each compression section. A multi-stage compression device characterized by having a plunger piston. 2. A diametrical gap between a cylinder in a compression section at the last stage and a piston reciprocating inside the cylinder in the last stage is smaller than a gap between a cylinder at a stage before the last stage and a piston reciprocating inside the cylinder. The multistage compression apparatus according to claim 1, wherein 3. The diametrical gap between the cylinder in the compression section in the preceding stage of the final stage and the piston reciprocating in the cylinder is 3 to 3 mm.
3. The multi-stage compression device according to claim 1, wherein the compression ratio is 10 [mu] m. 4. A diametrical gap between a cylinder in the final stage compression section and a piston reciprocating inside the cylinder is 2 to 8 μm.
The multistage compression apparatus according to any one of claims 1 to 3, wherein m is m. 5. A piston reciprocating inside a cylinder of a compression section at a stage before the final stage has a plurality of grooves on its surface, and a ratio of a groove depth B to a groove width A (B / A).
Is 0.2 to 0.5.
A multistage compression apparatus according to any one of the above. 6. The multi-stage compression apparatus according to claim 1, wherein said compression section has four stages.