JP4437864B2 - Reciprocating compressor suction / discharge valve - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a suction / discharge valve of a reciprocating compressor, and more particularly to a suction / discharge valve of a reciprocating compressor for LNG vaporized gas or the like.
[0002]
[Prior art]
The main body of the reciprocating compressor is composed of a crank mechanism that converts rotational motion into reciprocating motion, and a piston mechanism that is coupled to the crank mechanism and compresses gas. The crank mechanism includes a crank chamber, a crankshaft, a connecting rod, a main bearing, a crankpin bearing, and a piston bearing. The piston mechanism includes a cylinder, a cylinder cover, a suction valve, a discharge valve, a piston, and the like.
[0003]
In the case of the counterbalanced reciprocating compressor shown in FIG. 6, the crankshaft 2 is rotationally driven by a driving machine 1 such as an internal combustion engine or an electric motor, and the piston 5 is reciprocally driven via a connecting rod 3 (connecting rod) and a piston rod 4. The gas compressed on both sides of the I-stage cylinder 6 is further supplied to both sides of the II-stage cylinder 6 to be compressed and discharged to the outside.
[0004]
Each cylinder 6 in FIG. 6 sucks and discharges gas on both sides of the piston 5, and is provided with a suction valve at the suction port and a discharge valve at the discharge port. FIG. 7A is a principle diagram of the discharge valve. As shown in this figure, the discharge valve includes a valve receiver 7a, a valve plate 7b, a valve seat 7c, a valve spring 7d, and the like. The valve receiver 7a is fixed to the discharge port (lower side in the figure) of the cylinder 6 by sealing the outer peripheral surface of the valve receiver, and has a plurality of through holes 8a. The valve seat 7c is fixed integrally with the valve receiver 7a while maintaining a certain gap on the upper surface of the flow path portion of the valve receiver 7a, and the valve plate 7b is sandwiched between the gaps so that the valve seat 7c A valve spring 7d is provided to urge the valve receiver 7a.
[0005]
With this configuration, when the pressure in the cylinder to which the discharge valve is attached is low (for example, during suction), the valve plate 7b is pressed against the upper surface of the valve receiver 7a by the valve spring 7d, and the through hole 8a of the valve receiver 7a is closed. Then, the discharge valve 7 is closed. On the contrary, when the pressure in the piston is high (for example, at the time of discharge), the valve plate 7b is slightly lifted against the urging force of the valve spring 7d, and the valve seat, the valve plate, and the valve receiver are provided from the clearance. The pressurized gas is discharged to the outside through the through-hole 8a. Therefore, the discharge valve functions as a kind of check valve (or check valve).
[0006]
Similarly, as shown in FIG. 7B, the intake valve also includes a valve receiver 7a, a valve plate 7b, a valve seat 7c, a valve spring 7d, and the like. In the case of the intake valve, the valve spring 7d is incorporated in the valve receiver 7a, and the valve plate 7b is urged toward the valve seat 7c, and the through hole 8a is closed and gas-sealed. Further, the gas flow is in the direction opposite to that of the discharge valve, and it closes when the pressure in the cylinder is high, and opens when the pressure is low to suck low pressure gas from the outside. Hereinafter, unless otherwise specified, the discharge valve and the intake valve are collectively referred to as an “intake / discharge valve”.
[0007]
Furthermore, in order to reduce the suction resistance and / or discharge resistance and reduce the load on the compressor drive unit, a suction valve with an unloader that mainly holds the suction port (or discharge port) open as necessary is proposed. Has been. As shown in FIG. 8, this unloader-equipped suction valve includes a yoke rod 9 that penetrates the through hole 8c of the valve seat 7c, and the yoke rod 9 is moved downward as necessary by an opening / closing drive mechanism (not shown). The valve plate 7b is moved downward against the valve spring 7d to form a gap between the valve plate 7b and the valve seat 7c, and the cylinder is held in an open state through this gap. In addition, the discharge valve with an unloader by the same mechanism can also be comprised if necessary.
[0008]
[Problems to be solved by the invention]
In the above-described conventional suction / discharge valve, the valve plate 7b is violently driven by the pressure difference between the inside and outside of the cylinder, the force generated by the gas flow, the urging force of the valve spring, the inertia of the valve plate itself, and the like. Open and close when colliding with. For this reason, since the valve plate receives repeated impact loads, special steels (nickel chrome steel, nickel chrome molybdenum steel, stainless steel) having high toughness and fatigue strength have been used.
On the other hand, synthetic resin materials (nylon, polyamide) and the like have been used to reduce the inertia weight of the valve plate as a measure for reducing the impact load in the range from room temperature to 150 ° C.
[0009]
However, when such an intake / discharge valve is applied to a low temperature gas such as LNG vaporized gas, there are the following problems.
(1) A low temperature gas such as an LNG vaporized gas has a low temperature of, for example, about −150 ° C., and no lubricating oil can be used. For this reason, special steels such as nickel chrome steel and nickel chrome molybdenum steel have much wear under non-lubrication, and their life is reduced compared to the oil supply type. Further, low temperature brittleness due to low temperature is remarkably lowered, and fatigue failure is easily caused by an impact load caused by collision between the valve plate and the valve seat during operation. Furthermore, the noise caused by the collision between metals is intense.
(2) Stainless steel can be used without lubrication, but fatigue failure and noise cannot be avoided.
(3) By replacing the valve plate with resin, it is possible to avoid fatigue failure and reduce noise by reducing the impact load, but on the other hand, since the pressure resistance is low, the valve spring 7d and the yoke rod 9 The contact surface tends to wear due to surface pressure, and cannot withstand long continuous operation (for example, 8000 hours or more per year).
(4) Also, the resin has a lower bending rigidity than the special steel and is easily bent. Therefore, a gap is generated between the valve spring 7d and the yoke rod 9, and gas leakage is likely to occur.
[0010]
The present invention has been developed to solve such problems. That is, the object of the present invention is to suppress fatigue failure due to low temperature, reduce noise due to collision of the valve plate, reduce wear due to contact with the valve spring and yoke rod, and enable continuous operation for a long time and gas leakage An object of the present invention is to provide a suction / discharge valve for a reciprocating compressor capable of reducing the above.
[0011]
[Means for Solving the Problems]
According to the present invention, a valve seat (12) attached to the suction port or discharge port of the cylinder with its outer peripheral surface sealed, and a valve seat (14) for maintaining a certain clearance from the surface of the valve seat; A valve plate (16) made of cold-resistant resin that can move along the axis between the valve seat and the valve seat and can be used in a low-temperature gas atmosphere at around -150 ° C, and provided on the valve seat or the valve seat. A valve spring device (18) positioned in the plurality of recessed holes and urging the valve plate in the anti-spring direction. The valve spring device (18) is radially 45 to urge the valve plate substantially evenly. And a circular contact member (18a) and a valve spring (18b) for urging the circular contact member (18a) so as to reduce the surface pressure against the valve plate. The valve plate (16) has a plurality of arc-shaped through holes (12a, 16a) at the same position, and the arc-shaped through holes are the plurality of valve The valve device (18) is located in a portion avoiding the contact surface, extends in the circumferential direction and is spaced from each other in the radial direction, and the valve seat (14) is located adjacent to each other. Arc-shaped through holes (14a) extending in the circumferential direction and spaced apart from each other in the radial direction are arranged in a plane portion between the arc-shaped through holes (12a, 16a). A yoke rod (20) that can pass through (14a) and come into contact with the valve plate (16), and a contact end surface of the yoke rod extends through the arc-shaped through hole (14a) and has an arc-shaped penetration. A suction / discharge valve for a reciprocating compressor is provided, which extends along the hole (14a) and has an unloading function formed in a long cylindrical shape with rounded ends. The valve plate (16) is preferably a polyetheretherketone containing glass.
[0012]
According to the configuration of the present invention, the valve spring devices (18) are radially arranged in a plurality of rings so as to almost uniformly bias the valve plate (16). The interval can be pressed almost uniformly, and the deflection of the valve plate can be reduced. Therefore, when a resin valve plate is used, only the thickness of the valve plate is increased, and the deflection between the valve spring devices can be minimized and uniformly pressed, thereby preventing gas leakage.
Further, by using a resin valve plate, the impact load due to the weight reduction of the valve plate can be reduced, and the impact force at the time of opening and closing the valve can be halved and the noise can be drastically reduced compared to a metal valve plate.
Further, since the valve spring device (18) is composed of a contact member (18a) having a large-diameter circular contact surface and a valve spring (18b) for biasing the contact member (18a), the contact member (18a) The contact area between the valve plate and the valve plate can be increased to reduce the surface pressure, and the wear of the resin valve plate due to the valve spring can be eliminated, thereby extending the service life.
[0014]
Further , since the arcuate through hole (14a) of the valve seat (14) is located at a different part from the arcuate through hole (16a) of the valve plate (16), when the valve plate is pressed against the valve seat, The through-hole in the meantime closes and the valve can be fully closed. Since the valve receiver (12) and the valve plate (16) have arc-shaped through holes (12a, 16a) at the same position, when the valve plate is separated from the valve seat, The cylinder can be opened through the through hole (14a) in the valve seat. Accordingly, with this configuration, the suction / discharge valve can function as a suction valve. Further, since the yoke rod (20) that can be brought into contact with the valve plate (16) through the arc-shaped through hole (14a) of the valve seat is provided, the valve plate (16) is attached to the yoke rod (20). The suction / discharge valve can be normally opened (unloaded) by moving downward. Further, since the contact end surface of the yoke rod extends along the arc-shaped through hole (14a) and is formed in a long cylindrical shape with rounded ends, the space between the through holes when the valve plate is pressed against the valve seat is formed. While maintaining the same seal width, it can have an area several times that of a conventional circle, reducing the contact pressure of the yoke rod and eliminating its wear, enabling long-term continuous operation. Can be.
[0015]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings. In each figure, common portions are denoted by the same reference numerals, and redundant description is omitted.
FIG. 1 is an overall cross-sectional view of a suction valve of a suction / discharge valve of a reciprocating compressor according to the present invention. In this figure, the suction / discharge valve 10 of the present invention is a suction valve, and includes a valve receiver 12, a valve seat 14, a valve plate 16, a valve spring device 18, a yoke rod 20, and the like.
[0016]
The valve receiver 12 is incorporated in a cylinder inlet (not shown) with its periphery sealed. The valve seat 14 holds a gap h from the outer surface (upper surface in the drawing) of the valve receiver 12 and is fixed to the cylinder together with the valve receiver 12 via a valve pressing member (not shown). In this example, the valve plate 16 is made of resin, and is incorporated in the gap between the valve receiver 12 and the valve seat 14 so as to be movable only in the axial direction. The valve plate 16 is preferably made of polyetheretherketone containing glass that hardly changes over time in a low-temperature gas atmosphere at around −200 ° C. Further, it is desirable that the valve plate 16 is thicker than the valve plate in a gas atmosphere at about 150 ° C. so as to reduce the wear and breakage due to the deflection and surface pressure of the valve plate 16, for example, compared with the conventional metal plate of about 2 mm. In the case of a resin made of a verification result by the apparatus of the present invention, it is preferable that the thickness is about 6 mm.
[0017]
As shown in FIG. 1, the valve spring device 18 includes a relatively large-diameter circular contact member 18 a and a valve spring 18 b that urges the valve contact member 16 so as to reduce the surface pressure with the valve plate 16. . In this example, the valve spring device 18 is positioned in a recessed hole provided in the valve receiver 12 and biases the valve plate 16 in the valve seat direction (upward).
[0018]
With the configuration described above, the valve plate 16 can be biased toward the valve seat 14 by the valve spring device 18 when the pressure in the cylinder is high, and a gas seal can be sealed therebetween. On the contrary, when the pressure in the cylinder is low, the valve plate 16 is lowered by the negative pressure and the flow path is opened, so that low pressure gas can be sucked from the outside.
[0019]
Further, as shown in FIG. 1, the suction / discharge valve 10 of the present invention includes a yoke rod 20 that can pass through the arc-shaped through hole 14 a of the valve seat 14 and abut against the valve plate 16. The upper end of the yoke rod 20 is fixed to a yoke plate 21, and the yoke plate 21 is connected to a diaphragm holder 23 via a yoke rod 22. Further, the yoke plate 21 and the plurality of yoke rods 20 fixed thereto are biased upward by the two sets of springs 24a and 24b.
[0020]
With this configuration, the diaphragm restraint 23 is moved downward by air pressure, so that the valve plate 16 is moved inward (downward in the figure) at the tip (lower end in the figure) of the yoke rod 20, and this intake valve is always opened. It can be in a state (unloaded state).
[0021]
FIG. 2 is a plan view of the valve receiver 12 of FIG. As shown in this figure, a plurality of valve spring devices 18 are arranged radially so as to urge the valve plate 16 (indicated by a two-dot chain line in this figure) almost evenly. That is, as an example, 12 out of a total of 20 sets of valve spring devices 18 with a valve plate outer diameter of about 300 mm are arranged three in the orthogonal direction, and a total of eight in two directions in 45 directions. Has been placed. With this configuration, the distance between the adjacent valve spring devices 18 is reduced to about 75 mm from the conventional about 120 to 130 mm.
The valve receiver 12 has a plurality of arc-shaped through holes 12a. The arcuate through-holes 12a are located at portions other than the plurality of valve spring devices 18, and extend in the circumferential direction and are spaced apart from each other in the radial direction. The radial distance is about 15 mm in this example.
[0022]
FIG. 3 is a plan view of the valve plate 16. As shown in this figure, the valve plate 16 has a plurality of arc-shaped through holes 16 a at the same position as the valve receiver 12. The arc-shaped through holes 16a are located at portions other than the plurality of valve spring devices 18, and extend in the circumferential direction and are spaced apart from each other in the radial direction. That is, the portions that contact the plurality of valve spring devices 18 are flat surfaces without holes.
Further, as shown in FIGS. 2 and 3, the valve receiver 12 and the valve plate 16 have circular through holes 12b and 16b at the same position around the center hole, and an axis line is formed by a guide pin passing through the through hole. Thus, the arc-shaped through holes 12a and 16a are always located at the same position.
[0023]
The valve seat 14 has arcuate through holes 14a (see FIG. 5) that extend in the circumferential direction and are spaced apart from each other in the radial direction at portions different from the arcuate through holes 12a and 16a of the valve receiver 12 and the valve plate 16 . is doing. A plurality of the yoke rods 20 are radially arranged so as to urge the valve plate 16 substantially evenly. Furthermore, the tip shape ( contact end surface ) of the yoke rod 20 is not a conventional circular shape, but is formed in a long cylindrical shape extending along the arcuate through-hole 14a and rounded at both ends.
[0024]
5A and 5B are cross-sectional views showing the positional relationship between the valve receiver, the valve plate, and the valve seat. FIG. 5A shows a normal use time and FIG. 5B shows an unloading time.
During normal use (A), the arc-shaped through hole 14a of the valve seat 14 is located at a different portion from the arc-shaped through hole 16a of the valve plate 16 due to the above-described configuration. When not acting or when the pressure in the cylinder is high, the valve plate 16 is pressed against the valve seat 14 by the valve spring device, the through hole therebetween is closed, and the valve is fully closed. Further, since the valve receiver 12 and the valve plate 16 have arc-shaped through holes 12a and 16a at the same position, when a differential pressure (negative pressure) acts on the valve plate 16 and the valve plate 16 is separated from the valve seat 14, The cylinder can be opened through the through hole of the valve receiver 12 and the valve plate 16 and the through hole of the valve seat 14.
[0025]
Further, as shown in FIG. 5 (B), the valve plate 16 can be moved inward by the yoke rod 20, so that the suction / discharge valve can be always opened (unloaded).
[0026]
5A and 5B, the contact end surface of the yoke rod extends along the arcuate through hole 14a and is formed in a long cylindrical shape with rounded ends, so that the valve plate 16 is pressed against the valve seat 14. While maintaining the seal width between the through holes at this time (about 1.5 mm in this example), the yoke can have an area about 3 to 4 times that of a conventional circle (diameter 4 mm). It is possible to reduce the surface pressure at the contact portion of the rod to eliminate the wear and to enable continuous operation for a long time.
[0027]
In addition, this invention is not limited to the Example mentioned above, Of course, it can change variously in the range which does not deviate from the summary of this invention. For example, in the above-described example, the intake valve has been described in detail, but the present invention can be similarly applied to a discharge valve.
[0028]
【The invention's effect】
As described above, the suction / discharge valve of the reciprocating compressor according to the present invention avoids fatigue failure due to low temperature by drastically reducing the impact force, reduces the noise due to the collision of the valve plate, valve spring and yoke rod It has excellent effects such as reducing wear due to hitting, enabling continuous operation for a long time, and having a valve seal surface that is more flexible than metal touch and can reduce gas leakage.
[Brief description of the drawings]
FIG. 1 is an overall sectional view of a suction valve of a suction / discharge valve of a reciprocating compressor according to the present invention.
FIG. 2 is a plan view of the valve receiver of FIG.
FIG. 3 is a plan view of the valve plate of FIG. 1;
4 is a plan view of the valve seat of FIG. 1. FIG.
FIG. 5 is a cross-sectional view showing a positional relationship between a valve seat, a valve plate, and a valve receiver.
FIG. 6 is a schematic view of a counterbalanced reciprocating compressor.
FIG. 7 is a principle diagram of a discharge valve and a suction valve.
FIG. 8 is a principle diagram of a suction valve with an unloader.
[Explanation of symbols]
1 drive machine, 2 crankshaft, 3 connecting rod (connecting rod),
4 piston rod, 5 piston, 6 cylinder,
7a valve seat, 7b valve plate, 7c valve seat, 7d valve spring,
8a, 8c through hole, 9 yoke rod,
10 Suction / discharge valve, 12 Valve holder, 12a Arc-shaped through hole,
14 valve seat, 16 valve plate, 16a arcuate through hole,
18 valve spring device, 18a contact member, 18b valve spring,
20 Yoke bar, 20a Abutting end face,
21 yoke plate, 22 yoke rod,
23 Diaphragm suppression, 24a, 24b Spring

Claims (2)

A valve seat (12) attached to the suction port or discharge port of the cylinder with its outer peripheral surface sealed, a valve seat (14) that holds a certain clearance from the surface of the valve seat, and a valve seat and a valve seat A valve plate (16) made of a cold-resistant resin that can move along the axis and can be used in a low-temperature gas atmosphere around −150 ° C., and a plurality of recessed holes provided in the valve seat or the valve seat And a valve spring device (18) for biasing the valve plate in the anti-spring direction, and the valve spring device (18) is radially arranged at 45 degree intervals so as to bias the valve plate substantially evenly. And a circular contact member (18a) and a valve spring (18b) for urging it so as to reduce the surface pressure against the valve plate,
The valve receiver (12) and the valve plate (16) have a plurality of arc-shaped through holes (12a, 16a) at the same position, and the arc-shaped through holes are in contact with the plurality of valve spring devices (18). The valve seat (14) is located in a portion that avoids the surface and extends in the circumferential direction and spaced apart from each other in the radial direction, and the valve seat (14) is adjacent to the arc-shaped through holes (12a, 16a). ) Between the circular arc-shaped through holes (14a) extending in the circumferential direction and spaced apart from each other in the radial direction.
Furthermore, a yoke rod (20) that can contact the valve plate (16) through the arc-shaped through hole (14a) of the valve seat is provided, and the contact end surface of the yoke rod has an arc-shaped through hole (14a). An intake / discharge valve for a reciprocating compressor, wherein the intake / discharge valve has an unloading function and extends along the arc-shaped through hole (14a) and has a round cylindrical shape at both ends.   The suction / discharge valve of the reciprocating compressor according to any one of claims 1 to 3, wherein the valve plate (16) is made of polyetheretherketone containing glass.

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