VALVE FOR A PISTON COMPRESSOR AND METHOD FOR OPERATION OF SUCH A

Description

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

[0002] For the inlet and outlet valves of reciprocating compressors with larger stroke volumes, plate valves with a number of concentrically arranged flow ports are now most commonly used. These ports are typically covered by a valve plate made of steel or plastic. With one-piece valve plates, all areas of the plate are necessarily moved together, resulting in a relatively uniform load during opening and closing. However, such plates have disadvantages regarding flow direction and the associated flow losses.

[0003] It has already been proposed to design plate valves with sealing surfaces inclined in the flow direction, both on the valve seat and the valve plate. This leads to less flow deflection and thus lower flow losses. Such profiled valve seats and valve plates were described in AT514712A1. However, the valve plates used there have the disadvantage that, with unavoidable, minimal dimensional deviations during manufacturing and / or different thermal expansion behavior, small gaps inevitably form in sealing rings with inclined seat surfaces. These gaps only close after the closing pressure is applied, due to ring deformation. The connecting radial webs between the sealing rings must therefore be specially designed to counteract this undesirable sealing behavior. Manufacturing the sealing plate becomes complex and costly.

[0004] Documents US 4703772 and FR1061785 disclose valves with a multitude of flow channels, into whose valve seats protrude projections which guide the fluid flow.

[0005] It is therefore the object of the present invention to overcome the disadvantages of the prior art. In particular, it is the object of the present invention to provide a valve for a piston compressor which ensures improved flow control, while the valve plate can nevertheless be manufactured simply and cost-effectively. This object is achieved by a valve and a method comprising the features of the independent claims.

[0006] The problem is solved in particular by a valve for a piston compressor, comprising a valve seat with a plurality of flow channels opening into an end face of the valve seat; a valve plate having a flat sealing surface designed to control the flow channels of the valve seat; wherein the valve plate extends in a plane parallel to the front face of the valve seat, is arranged concentrically to the valve seat and has passage openings spatially offset from the flow channels of the valve seat, characterized in that at least one projection is arranged on the front face of the valve seat which, at least in a closed valve state, projects into a passage opening of the valve plate and is designed as a part that can be inserted into and removed from the valve seat (2) and is made of plastic, preferably PTFE, wherein the valve seat (2) is metallic.

[0007] For the purposes of the invention, a "flat" sealing surface means that the valve plate does not have a profiled sealing surface, in particular no chamfered edge of a passage opening towards the valve seat. Typically, the valve plate has no projections or indentations whatsoever. The valve plate is preferably formed from a flat substrate, for example, a stainless steel sheet, in particular by stamping, milling, or cutting. This typically results in an angle of approximately 90° between the sealing surface and the walls of the passage openings.

[0008] The valve according to the invention has the advantage that flow deflection is optimized and flow losses are reduced, thereby improving valve efficiency. Nevertheless, the flat valve plate can be manufactured cost-effectively and efficiently. The flat sealing surface of the preferably one-piece valve plate ensures uniform stress across the different areas of the sealing surface during opening and closing. The uniform surface texture helps to keep the leakage rate low.

[0009] In a preferred embodiment, the valve as described above additionally comprises a catch arranged such that the valve plate extends between the valve seat and the catch. The catch may have recesses, e.g., blind holes, to accommodate springs. The valve as described above may include springs arranged on the catch to bias the valve plate against the face of the valve seat so that the valve is closed in the depressurized state.

[0010] It is preferred if the valve plate and the valve seat each have the shape of an annular plate. It is particularly preferred if the flow channels and the through-openings are each designed as slots in the form of concentric circular arcs when viewed from above.

[0011] Plate valves of this type are known in various designs. When such valves are in operation, the valve plate performs a stroke movement between the valve seat and the retainer, alternately closing (closed valve state) and opening (open valve state) the flow channels of the valve seat. However, such plate valves tend to suffer from flow losses due to the considerable flow deflection between the flow channels and the orifices. The solution presented here combines the advantages of the plate valve, such as uniform load distribution, long service life, and high leakage resistance, with improved flow deflection.

[0012] In a preferred embodiment, the flat sealing surface of the valve plate rests partially on the end face of the valve seat when the valve is closed, with the contact areas extending perpendicular to the flow channels of the valve seat. This embodiment ensures good sealing performance without any sealing delay during valve closure. It thus differs from known valve plates in which chamfered sealing surfaces interact with corresponding, opposing seating surfaces on the valve seat to optimize flow.

[0013] A valve as described above is particularly preferred, further comprising an auxiliary plate, preferably a damper plate, extending between the valve plate and the catch in a plane parallel to the face of the valve seat. The springs preferably project through holes in the auxiliary plate to press the valve plate against the face of the valve seat. The auxiliary plate can serve to dampen the impacts of the valve plate on the catch and / or, if necessary, to guide it during the stroke. The former is particularly necessary if the valve plate is made of steel or a nickel-based alloy (Hastelloy). Alternatively, a single, non-metallic valve plate can be used instead of a valve plate and an auxiliary plate. Such a plate is typically made of a high-performance thermoplastic polymer such as fiber-reinforced PEEK and / or polyimide.Such plates have higher toughness, impact resistance and resistance to damage from liquids or contaminants.

[0014] In a preferred embodiment, a plurality of projections are arranged on the end face of the valve seat, each of which projects into a corresponding through-hole of the valve plate, at least when the valve is closed. The efficiency-enhancing effect of flow deflection can be optimized by using at least one projection per through-hole. It is particularly preferred if, as described above, the through-holes of the valve plate are designed as arc-shaped slots and the projections on the end face of the valve seat are designed as corresponding arc-shaped projections. Thus, in the closed valve state, a longitudinal projection, which essentially follows the shape of the through-hole, projects into each through-hole of the valve plate.

[0015] In one embodiment, the at least one projection has a cross-section that tapers towards the valve plate, preferably conically, and most preferably via a concave lateral curvature. If the projections are arc-shaped, a radial cross-section is meant. "Concave lateral curvature" means that the tapered sides have a radius of curvature in cross-section or a variable slope, particularly one that increases towards the valve plate.

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

[0017] Alternatively, at least one projection can be made of plastic, preferably PTFE. In this case, the projection is connected to the metallic valve seat, for example, by positive or non-positive engagement with a corresponding recess in the valve seat. In a preferred embodiment, the projection is an annular or arc-shaped piece that fits into a corresponding groove on the face of the valve seat. Using separate parts allows for greater flexibility in material selection, and the interchangeability simplifies maintenance, for example, resurfacing or machining.

[0018] One aspect of the invention relates to a method for operating a valve for a piston compressor, wherein the valve comprises a valve seat and a valve plate, the valve seat having a plurality of flow channels opening into an end face of the valve seat, and the valve plate having a flat sealing surface extending in a plane parallel to the end face of the valve seat, arranged concentrically to the valve seat and having passage openings spatially offset from the flow channels of the valve seat, wherein the valve plate blocks the flow channels in a closed valve state and releases them in an open valve state, and wherein the valve plate assumes the open state when it automatically lifts off the valve seat due to a fluid pressure applied to the valve, so that fluid flows through the flow channels of the valve seat and downstream through the passage openings of the valve plate.characterized in that fluid is directed via a projection arranged on the valve plate of the valve seat into a through-opening of the valve plate.

[0019] This method also solves the problem described above. It optimizes flow deflection and reduces flow losses, thereby improving valve efficiency. Despite this, the flat valve plate can be manufactured cost-effectively and efficiently. The flat sealing surface of the valve plate ensures uniform stress distribution across the different areas of the sealing surface during opening and closing. The uniform surface texture prevents fitting inaccuracies and keeps the leakage rate low.

[0020] It is preferred that, in the method described above, the fluid is directed into a corresponding through-opening in the valve plate via a plurality of projections arranged on the end face of the valve seat. The fluid can be directed into at least one through-opening in the valve plate via at least one projection tapering towards the valve plate, preferably a projection with a conical cross-section, and particularly preferably a projection having concave side bulges.

[0021] One aspect of the invention relates to a piston compressor comprising a valve as described above.

[0022] The invention is further explained by the figures and the following explanations. The figures show preferred embodiments and do not limit the scope of the invention.

[0023] They show: Figure 1A Cross-section through a known plate valve (prior art); Figure 1B Perspective exploded view of a known plate valve (prior art); Figure 1C Cross-section through a known plate valve (prior art), detail; Figure 2 Cross-section through a plate valve according to an embodiment of the invention; Figure 3 Cross-section through a plate valve according to an embodiment of the invention, detail; Figure 4 Cross-section through a plate valve according to an embodiment of the invention; Figure 5 Cross-section through a plate valve according to an embodiment of the invention, detail;

[0024] The Figures 1A to 1CFigure 1 shows a valve for a piston compressor, as known in the prior art. The valve 1 has a valve seat 2 with a plurality of flow channels 12 opening into an end face 3 of the valve seat 2. The valve further has a valve plate 4, which has a flat sealing surface 5 designed to control the flow channels 12 of the valve seat 2. The valve plate 4 extends in a plane parallel to the end face of the valve seat.

[0025] The valve seat 2 and the valve plate 4 are in the shape of ring plates and are arranged concentrically. Figure 1B It is evident that the flow channels 12 of the valve seat 2 and the through-openings 14 of the valve plate 4 are spatially offset from each other. Specifically, it would be apparent in the top view (not shown) that these are slots in the form of circular arcs, concentric to the central axis. The circular arcs do not extend over the entire circumference.

[0026] Furthermore, in Figure 1B A catch 6 is shown, arranged such that the valve plate 4 extends between the valve seat 2 and the catch 6. The catch 6 has a slot pattern of through-channels 16, which corresponds to that of the through-openings 14 of the valve plate 4. The valve comprises a plurality of springs 9, 9' arranged on the catch 6 to move the valve plate 4 against the face 3 of the valve seat 2. Specifically, the springs 9, 9' are arranged in recesses 8 of the catch 6, which in Figure 1C is visible. Finally, it is in the Figure 1B Also shown is a damper plate 7 extending between the valve plate 4 and the catch 6 in a plane parallel to the front face 3 of the valve seat 2, wherein the springs 9, 9' protrude through holes 11 in the damper plate 7 to load the valve plate 4 against the front face 3 of the valve seat 2.

[0027] The central axis, with respect to which the ring plates are arranged concentrically, is formed by a central screw 22. The central screw 22 projects as a retaining hub against the valve seat 2. The valve is stabilized by wedge-locking washers 20, and the valve and damper plates can be spaced apart from each other by cam discs 21. A pin 23 can be used to prevent unintentional rotation of the various ring plates.

[0028] Figure 2 Figure 1 shows an axial section through a valve according to the invention in the area of ​​a series of coil springs 9, 9'. The coil springs 9, 9' are each fixed at their upper ends in a blind bore of the catch 6. The other, lower end of the coil spring 9, 9' presses the valve plate 4 against any gas pressure or vacuum towards the valve seat 2. A damper plate 7 with holes 11, through which springs 9, 9' protrude, is also shown.

[0029] Figure 3 Figure 1 shows a radial section through a valve 1 according to the invention, now in the area of ​​a flow channel 12 of the valve seat 2 and a radially offset through-opening 14 in the valve plate 4, or flow channel 16 of the catch 6. The damper plate 7 also has the slot pattern of the valve plate 4 and catch 6. It is evident that a projection 10 is arranged on the end face 3 of the valve seat. The valve is shown in a closed state. The flat sealing surface 5 of the valve plate 4 rests partially on the end face 3 of the valve seat 2, such that the bearing areas 13 extend perpendicular to the flow channels 12 of the valve seat 2.

[0030] In the illustrated embodiment, the projection 10 protrudes through the valve plate 4 in the closed valve state, but not through the damper plate 7. However, other embodiments are conceivable. It is not apparent that the passage openings 14 of the valve plate 4 are designed as arc-shaped slots and that the projections 10 on the end face 3 of the valve seat 2 are designed as corresponding arc-shaped projections. This variant is suitable for an annular valve, as is the case in Figure 1B As shown, preferred.

[0031] Out of Figure 3 It then becomes apparent that the projection 10 tapers in its radial cross-section towards the valve plate 4 and specifically converges via concave lateral bulges 15, i.e., the slope of each converging side becomes steeper towards the valve plate 4. The projection 10 is formed integrally with the valve seat 2.

[0032] Figure 4Figure 1 shows an axial section through a valve according to the invention in the area of ​​a series 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 annular, separate parts that are force-fitted and interchangeably fitted into corresponding grooves of the valve seat 2.

[0033] In the detailed view of Figure 5 It is evident that the projections 10 in the radial section also converge via concave lateral bulges, at least in the area of ​​a passage opening 14 of the valve plate 4.

Claims

1. Valve (1) for a piston compressor comprising - a valve seat (2) with a plurality of flow channels (12) which open into an end face (3) of the valve seat (2); - a valve plate (4) having a planar sealing surface (5) which is configured to control the flow channels (12) of the valve seat (2); wherein the valve plate (4) extends in a plane parallel to the end face (3) of the valve seat (2), is arranged concentrically to the valve seat (2) and has passage openings (14) spatially offset from the flow channels (12) of the valve seat (2), characterized in that at least one projection (10) is arranged on the end face (3) of the valve seat (2) which, at least in a closed valve state, projects into a passage opening (14) of the valve plate (4) and is configured as a part insertable into the valve seat (2) and removable from the valve seat (2) and is made of plastic, preferably PTFE, wherein the valve seat (2) is metallic.

2. Valve (1) according to claim 1, further comprising a retainer (6) which is arranged such that the valve plate (4) extends between the valve seat (2) and the retainer (6), wherein springs (9, 9') are preferably arranged on the retainer (6) to bias the valve plate (4) against the end face (3) of the valve seat (2).

3. Valve (1) according to any of the preceding claims, wherein the planar sealing surface (5) of the valve plate (4) rests partially on the end face (3) of the valve seat (2) in a closed valve state, wherein the contact areas (13) extend perpendicularly to the flow channels (12) of the valve seat.

4. Valve (1) according to claim 2 or 3, further comprising - an auxiliary plate (7) extending between the valve plate (4) and the retainer (6) in a plane parallel to the end face (3) of the valve seat (2), preferably a damper plate, wherein preferably the springs (9, 9') project through holes (11) in the auxiliary plate (7) to bias the valve plate (4) against the end face (3) of the valve seat (2).

5. Valve (1) according to any of the preceding claims, wherein a plurality of projections (10) are arranged on the end face (3) of the valve seat (2) which, at least in the closed valve state, each project into a corresponding passage opening (14) of the valve plate (4).

6. Valve (1) according to claim 4, wherein the passage openings (14) of the valve plate (4) are configured as arc-shaped slots and the projections (10) on the end face (3) of the valve seat (2) are configured as corresponding arc-shaped projections.

7. Valve (1) according to any of the preceding claims, wherein the at least one projection (10) has a cross-section which tapers towards the valve plate (4), preferably tapers conically, particularly preferably tapers via concave side curvatures (15).

8. Method for operating a valve for a piston compressor, wherein the valve comprises a valve seat (2) and a valve plate (4), wherein the valve seat (2) has a plurality of flow channels (12) and an end face (3) into which the flow channels (12) open, and the valve plate (4) has passage openings (14) spatially offset from the flow channels (12) of the valve seat (2), wherein the valve plate (4) blocks the flow channels (12) in a closed valve state and releases them in an open valve state, and wherein the valve plate (4) assumes the open state when it automatically lifts off the valve seat (2) due to a fluid pressure applied to the valve, so that fluid flows through the flow channels (12) of the valve seat (2) and downstream through the passage openings (14) of the valve plate (4), characterized in that fluid is directed via a projection (10), arranged on the end face (3) of the valve seat (2), into a passage opening (14) of the valve plate (4), wherein the projection (10) is configured as a part insertable into the valve seat (2) and removable from the valve seat (2) and is made of plastic, preferably PTFE, wherein the valve seat (2) is metallic.

9. Method according to claim 8, wherein the fluid is directed via a plurality of projections (10) arranged on the end face (3) of the valve seat (2) each into a corresponding passage opening (14) of the valve plate (4).

10. Method according to claim 8, wherein the fluid is directed via at least one projection (10) tapering towards the valve plate (4), preferably a projection (10) conically tapering in cross-section, particularly preferably a projection (10) having concave side curvatures (15), into at least one passage opening (14) of the valve plate (4).

11. Piston compressor having a valve according to any of claims 1 to 7.