Valve for a piston compressor and method for operating such a valve

Abstract

The invention relates to a valve (1) for a piston compressor, comprising a valve seat (2) with a plurality of flow passages (12) opening into an end face (3) of the valve seat (2), and a valve plate (4) having a flat sealing surface (5) and designed to control the flow passages (12) of the valve seat (2), the valve plate (4) having passage openings (14) that are spatially offset with respect to the flow passages (12) of the valve seat (2), and one or more protrusions (10) are arranged on the end face (3) of the valve seat (2) and protrude into the passage openings (14) of the valve plate (4) at least in a closed valve state.

Description

[Technical field]

[0001] The present invention relates to the technical field of reciprocating compressors. [Background technology]

[0002] Nowadays, plate valves with multiple concentrically arranged flow openings, covered by a valve plate, usually made of steel or plastic, are used as inlet and outlet valves for reciprocating compressors with larger stroke volumes. In a one-piece valve plate, all areas of the plate are moved together, which results in a relatively uniform load when opening and closing. However, such plates have disadvantages with regard to flow control and the associated flow losses.

[0003] It has already been proposed to provide plate valves with sealing surfaces inclined in the direction of flow, both on the valve seat and on the valve plate. This leads to less flow deflection and therefore less flow losses. Valve seats and valve plates with such profiles are described in EP 1 339 636. However, the valve plates used in EP 1 339 636 have the disadvantage that in the case of unavoidable small dimensional deviations during manufacture and / or different thermal expansion behavior, small gaps are inevitably formed in the sealing rings with inclined sealing surfaces, which close only after the application of a closing pressure due to deformation of the rings. The connecting radial bars between the sealing rings therefore need to be specially designed to counter this undesirable sealing behavior. The manufacture of the sealing plates is complex and costly. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Austrian Patent Application Publication No. 514712 Summary of the Invention [Problem to be solved by the invention]

[0005] It is therefore an object of the present invention to overcome the drawbacks of the prior art, in particular to provide a valve for a reciprocating compressor which ensures improved flow control and yet allows the valve plate to be produced simply and inexpensively. [Means for solving the problem]

[0006] This problem is solved by a valve and a method having the features of the independent claims. The problem is particularly related to valves for piston compressors, a valve seat having a plurality of flow passages opening to an end face of the valve seat; a valve plate having a flat sealing surface designed to control the flow path of the valve seat; The valve plate extends in a plane parallel to the end face of the valve seat, is arranged concentrically with the valve seat and has a passage opening that is spatially offset with respect to the flow passage of the valve seat, and one or more protrusions are arranged on the end face of the valve seat and protrude into the passage opening of the valve plate, at least in a closed valve state.

[0007] For the purposes of the present invention, a "flat" design of the sealing surface means that the valve plate does not have a contoured sealing surface, in particular does not have an inclined edge of the passage opening towards the valve seat. Typically, the valve plate does not have any protrusions or recesses. Particularly advantageously, the valve plate is formed from a flat substrate, for example a stainless steel sheet, in particular punched, milled or cut. Typically, an angle of substantially 90° is thereby formed between the sealing surface and the wall of the passage opening.

[0008] The advantage of the valve according to the invention is that the flow deflection is optimized and the flow losses are reduced, thereby improving the valve efficiency. Nevertheless, the flat valve plate can be manufactured cost-effectively and efficiently. The flat sealing surface of the advantageously one-piece valve plate ensures uniform loading over the various areas of the sealing surface when opening and closing. The uniform nature of the surface allows the leakage rate to be kept low.

[0009] In a preferred embodiment, the valve further comprises a catcher arranged such that the valve plate extends between the valve seat and the catcher. The catcher may have a recess, e.g. a blind bore, for receiving a spring. The valve may comprise a spring arranged in the catcher to load the valve plate against a face of the valve seat such that the valve closes when reduced pressure is applied.

[0010] The valve plate and the valve seat each preferably have the shape of an annular plate. The flow passages and the through openings are particularly preferably each designed as slots in the form of concentric circular arcs when viewed from above.

[0011] Plate valves of this kind are known in various designs. When such valves are operated, the valve plate undergoes an upward movement between the valve seat and the catcher, alternately closing (closed valve state) and opening (open valve state) the flow passages of the valve seat. However, such plate valves tend to suffer from flow losses due to significant flow deflection between the flow passages and the passage openings. The solution presented here combines the advantages of plate valves, such as uniform loading, long life cycle, and high leakage resistance, with improved flow deflection.

[0012] In a preferred embodiment, in a closed valve state, the flat sealing surface of the valve plate rests on several areas on the face of the valve seat, and the contact areas extend perpendicular to the flow path of the valve seat. This design ensures good sealing performance without sealing delay during valve closing. Therefore, it differs from known valve plates in which an inclined sealing surface interacts with a corresponding opposing valve seat on the valve seat to optimize flow.

[0013] Particularly preferred is a valve as described above, further comprising an auxiliary plate, preferably a damper plate, extending between the valve plate and the catcher in a plane parallel to the end face of the valve seat, the spring protruding through a hole in the auxiliary plate so as to load the valve plate against the end face of the valve seat. The auxiliary plate can serve to damp the impact of the valve plate against the catcher and / or to guide the catcher during its upward movement, if necessary. The former is particularly necessary when the valve plate is made of steel or nickel-based alloy (Hastelloy). Alternatively, a single non-metallic valve plate can be used instead of the valve plate and the auxiliary plate. Such plates are typically made of thermoplastic high-performance polymers such as fiber-reinforced PEEK and / or polyimide. Such plates have higher toughness, impact resistance and resistance to damage by liquids or contamination.

[0014] In an advantageous configuration, a number of protrusions are arranged on the end face of the valve seat, each of which protrudes into a corresponding through-opening in the valve plate, at least when the valve is closed. The efficiency-increasing effect of the flow deflection can be optimized by using more than one protrusion for each passage opening. It is particularly preferred in such valves that the passage openings in the valve plate are designed as arc-shaped slots and the protrusions on the end face of the valve seat are designed as corresponding arc-shaped protrusions. Thus, when the valve is closed, a longitudinal protrusion that essentially follows the shape of the passage opening protrudes into each passage opening of the valve plate.

[0015] In one embodiment, the one or more protrusions have a cross section that tapers towards the valve plate, preferably conically tapered, particularly preferably via a concave side curvature. In the case of a circular protrusion, a radial cross section is meant. "Concave side curvature" is understood to mean that the tapered side has a radius of curvature in cross section or has a variable inclination, particularly an increasing inclination towards the valve plate.

[0016] In one embodiment, the one or more protrusions are integrally formed with the valve seat. The one or more protrusions can be, for example, milled or turned from the valve seat. This embodiment has the advantage that the protrusions are particularly durable and inert.

[0017] Alternatively, one or more protrusions may be made of plastic, preferably PTFE. In this case, the protrusions are connected to the metal valve seat and are, for example, securely or non-securely inserted into corresponding recesses in the valve seat. In a preferred embodiment, the protrusions are annular or arc-shaped parts that fit into corresponding grooves on the face of the valve seat. If separate parts are used, the choice of material becomes more flexible and, thanks to interchangeability, maintenance, for example, reversing or machining, is simplified. One aspect of the invention relates to a method of operating a valve for a reciprocating compressor, the valve comprising a valve seat and a valve plate, the valve seat having a plurality of flow passages opening to an end face of the valve seat, the valve plate having a flat sealing surface extending in a plane parallel to the end face of the valve seat and arranged concentrically with the valve seat and having passage openings (14) spatially offset with respect to the flow passages in the valve seat, the valve plate blocking the flow passages in a closed valve state and opening the flow passages in an open valve state, the valve plate assuming the open valve state when it is automatically lifted off the valve seat due to fluid pressure on the valve, such that fluid flows through the flow passages in the valve seat and downstream through the passage openings in the valve plate, and fluid is directed to the passage openings in the valve plate via a protrusion arranged on the valve plate of the valve seat.

[0018] This method also solves the above mentioned problems. The method optimizes the flow deflection and reduces flow losses, thereby improving valve efficiency. Nevertheless, the flat valve plate can be manufactured cost-effectively and efficiently. The flat sealing surface of the valve plate ensures uniform loading over the various areas of the sealing surface when opening and closing. The uniform nature of the surface avoids inaccuracies in the installation and allows the leakage rate to be kept low.

[0019] In the above method, the fluid is preferably directed to the corresponding passage openings in the valve plate via a plurality of protrusions arranged on the end face of the valve seat. The fluid can be directed to the one or more passage openings in the valve plate via one or more protrusions tapered towards the valve plate, preferably protrusions with a tapered cross section, particularly preferably protrusions with a concave side curvature.

[0020] One aspect of the invention relates to a piston compressor comprising a valve as described above. The invention is further illustrated by the drawings and the following description, in which: The drawings show preferred embodiments and are not intended to limit the subject matter of the invention. [Brief description of the drawings]

[0021] [Figure 1A] FIG. 1 is a cross-sectional view of a known plate valve (prior art). [Figure 1B] FIG. 1 is a perspective exploded view of a known plate valve (prior art). [Figure 1C] FIG. 1 is a detailed cross-sectional view of a known plate valve (prior art). [Diagram 2] 1 is a cross-sectional view of a plate valve according to one embodiment of the present invention. [Diagram 3] FIG. 2 is a detailed cross-sectional view of a plate valve according to one embodiment of the present invention. [Figure 4] 1 is a cross-sectional view of a plate valve according to one embodiment of the present invention. [Diagram 5] FIG. 2 is a detailed cross-sectional view of a plate valve according to one embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0022] 1A-1C show a valve for a piston compressor as known in the prior art. The valve 1 has a valve seat 2 with a number of flow passages 12 which open into an end face 3 of the valve seat 2. The valve also has a valve plate 4 with a flat sealing surface 5 which is designed to control the flow passages 12 of the valve seat 2. The valve plate 4 extends in a plane parallel to the end face of the valve seat.

[0023] The valve seat 2 and the valve plate 4 have the shape of annular plates and are arranged concentrically. Figure 1B shows that the passages 12 in the valve seat 2 and the passage openings 14 in the valve plate 4 are spatially offset from one another. In particular, in a plan view (not shown), it can be seen that the slots are in the form of circular arcs concentric with a central axis. The arcs do not extend around the entire circumference of a circle.

[0024] FIG. 1B also shows a catcher 6, which is arranged such that the valve plate 4 extends between the valve seat 2 and the catcher 6. The catcher 6 has a slot pattern of passage channels 16 that corresponds to the pattern of passage openings 14 of the valve plate 4. The valve comprises a number of springs 9, 9 arranged on the catcher 6 to move the valve plate 4 against the end face 3 of the valve seat 2. Specifically, the springs 9, 9' are arranged in recesses 8 of the catcher 6, which can be seen in FIG. 1C. Finally, FIG. 1B also shows a damper plate 7, which extends between the valve plate 4 and the catcher 6 in a plane parallel to the end face 3 of the valve seat 2, and the springs 9, 9' protrude through holes 11 in the damper plate 7 to load the valve plate 4 against the end face 3 of the valve seat 2.

[0025] The central axis is formed by a central screw 22, about which the ring plates are concentrically arranged. The central screw 22 protrudes as a catcher hub against the valve seat 2. The valve is stabilized by a wedge lock washer 20, and the valve plate and the damper plate can be spaced apart from each other by a lifting washer 21. A pin 23 can be used to prevent unintentional rotation of the various ring plates.

[0026] Figure 2 shows an axial section through the valve according to the invention in the region of the row of coil springs 9, 9'. The upper ends of the coil springs 9, 9' are each fixed in a blind bore in the catcher 6. The other lower ends of the coil springs 9, 9' press the valve plate 4 in the direction of the valve seat 2 against any gas pressure or vacuum. Also shown is the damper plate 7 with holes 11 through which the springs 9, 9' protrude.

[0027] FIG. 3 shows a radial section through the valve 1 according to the invention, here in the region of the flow passage 12 of the valve seat 2, the radially offset passage openings 14 in the valve plate 4 and the flow passage 16 of the catcher 6. The damper plate 7 also has the slot pattern of the valve plate 4 and the catcher 6. It can be seen that the protrusions 10 are arranged on the end face 3 of the valve. The valve is shown in the closed state. The flat sealing surface 5 of the valve plate 4 rests in several areas on the end face 3 of the valve seat 2, so that the contact areas 13 extend perpendicularly to the flow passages 12 of the valve seat 2.

[0028] In the embodiment shown, the projection 10 projects through the valve plate 4 but not through the damper plate 7 when the valve is closed. However, other embodiments are also conceivable. It is not shown here that the passage opening 14 in the valve plate 4 is designed as an arc-shaped slot and the projection 10 on the end face 3 of the valve seat 2 is designed as a corresponding arc-shaped projection. This variant is preferred for annular valves as shown in FIG. 1B.

[0029] 3 shows that the protrusion 10 tapers in radial cross section towards the valve plate 4, specifically across the concave side curvature 15, i.e. the slope of each tapered side becomes steeper towards the valve plate 4. The protrusion 10 is formed integrally with the valve seat 2.

[0030] 4 shows an axial section through the valve according to the invention in the region of the row of coil springs 9. In this embodiment, the projections 10 are designed as parts that can be inserted into and removed from the valve seat 2. They are separate ring-shaped parts that fit in a friction-locking and replaceable manner into corresponding grooves in the valve seat 2.

[0031] In the detailed view of FIG. 5 it can be seen that the projection 10 is also tapered over a concave side curvature in radial cross section, at least in the region of the passage opening 14 in the valve plate 4 .

Claims

1. A valve (1) for a piston compressor, comprising: a valve seat (2) having a plurality of flow passages (12) opening onto an end face (3) of the valve seat (2); a valve plate (4) having a flat sealing surface (5) designed to control the flow path (12) of the valve seat (2); the valve plate (4) extends in a plane parallel to the end face (3) of the valve seat (2), is arranged concentrically with the valve seat (2), and has a passage opening (14) that is spatially offset with respect to the flow passage (12) of the valve seat (2); The valve (1) has one or more protrusions (10) disposed on the end face (3) of the valve seat (2) and protruding into a passage opening (14) in the valve plate (4) at least in a closed valve state.

2. 2. The valve of claim 1, further comprising a catcher (6), the catcher (6) being arranged such that the valve plate (4) extends between the valve seat (2) and the catcher (6), and preferably a spring (9, 9') being arranged on the catcher (6) so as to load the valve plate (4) against the end face (3) of the valve seat (2).

3. 3. A valve according to claim 1 or 2, wherein in a closed valve state, the flat sealing surface (5) of the valve plate (4) rests on an area (13) on the end face (3) of the valve seat (2), the area (13) extending perpendicular to the flow passage (12) of the valve seat.

4. an auxiliary plate (7), preferably a damper plate, extending between the valve plate (4) and the catcher (6) in a plane parallel to the end face (3) of the valve seat (2); 3. A valve (1) according to claim 2, wherein the springs (9, 9') preferably protrude through holes (11) in the auxiliary plate (7) so as to load the valve plate (4) against the end face (3) of the valve seat (2).

5. 3. The valve (1) according to claim 1 or 2, wherein a plurality of protrusions (10) are arranged on the end face (3) of the valve seat (2) and each protrude into a corresponding passage opening (14) of the valve plate (4) at least in the closed valve state.

6. 5. A valve according to claim 4, wherein the passage opening (14) of the valve plate (4) is formed as an arcuate slot and the protrusion (10) on the end face (3) of the valve seat (2) is formed as a corresponding arcuate protrusion.

7. 3. A valve (1) according to claim 1 or 2, wherein the one or more protrusions (10) have a cross section that tapers towards the valve plate (4), preferably conically tapered, particularly preferably tapered with a concave side curvature (15).

8. 3. A valve (1) according to claim 1 or 2, wherein one or more of said projections (10) are formed in one piece with said valve seat (2).

9. 8. A valve according to claim 7, wherein one or more of the protrusions (10) are milled or turned from the valve seat (2).

10. 3. A valve according to claim 1 or 2, wherein one or more of the protrusions (10) are designed as parts that can be inserted into and removed from the valve seat (2).

11. 10. A valve according to claim 9, wherein the one or more protrusions (10) are made of plastic, preferably PTFE.

12. A method of operating a valve for a reciprocating compressor, the valve comprising a valve seat (2) and a valve plate (4), The valve seat (2) has a plurality of flow passages (12) and an end face (3), the flow passages (12) opening into the end face (3), and the valve plate (4) has passage openings (14) spatially offset with respect to the flow passages (12) of the valve seat (2); the valve plate (4) blocks the flow path (12) in a closed valve state and releases the flow path (12) in an open valve state, the valve plate (4) assuming the open valve state when it automatically lifts off the valve seat (2) due to fluid pressure on the valve, resulting in fluid flow through the flow path (12) in the valve seat (2) and downstream through the passage opening (14) in the valve plate (4); The method, wherein the fluid is directed to a passage opening (14) in the valve plate (4) via a protrusion (10) disposed on the valve plate (3) of the valve seat (2).

13. 13. The method of claim 12, wherein the fluid is directed to the corresponding passage openings (14) in the valve plate (4) via a plurality of protrusions (10) arranged on the end face (3) of the valve seat (2).

14. 14. The method according to claim 12 or 13, wherein the fluid is directed towards one or more passage openings (14) in the valve plate (4) via one or more protrusions (10) tapering towards the valve plate (4), preferably conically tapering in cross section, particularly preferably having a concave side curvature (15).

15. A piston compressor comprising a valve according to claim 1 or 2.

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