Automatic locking elastic knife gate valve seat

Abstract

Embodiments disclosed herein relate to a knife gate valve having a valve body defining a bore, and a gate plate for the bore, the knife gate valve comprising: an inner surface of the valve body; an annular groove entirely defined within the inner surface; the step-shaped surface and the first locking surface are limited in the annular groove, and the first locking surface is adjacent to and connected with the step-shaped surface; the elastic valve seat ring is inserted into the annular groove, the elastic valve seat ring is provided with a wedge-shaped part, the wedge-shaped part defines an inclined surface, and the wedge-shaped part is mounted across the stepped surface of the annular groove; the second locking surface is limited on the elastic valve seat, and the second locking surface is adjacent to and connected with the inclined surface; and further wherein the first locking surface and the second locking surface are configured to abut against each other.

Description

TECHNICAL FIELD

[0001] The present invention relates generally to resilient seat devices and techniques for knife gate valves. BACKGROUND

[0002] Conventional knife gate valves are commonly used to control the flow of slurries, paper, and pulp through tubular conduits. Depending on the flow direction, knife gate valves (hereinafter also referred to as "KGVs") generally have two variations, namely, one-way knife gate valves and two-way knife gate valves. In these variations, the valve seat design can be either a metallic seat or a resilient seat. In conventional resilient seat KGVs, the resilient seat can be an elastomer or a plastic material and can be sealed against the face or the periphery of the gate. When using conventional elastomer seats, there are temperature limitations when using materials such as nitrile rubber, ethylene propylene diene rubber (EPDM), or fluoroelastomer (FKM), for example. Therefore, for valves rated at 200 degrees Celsius (or 392 degrees Fahrenheit) or higher, plastic seats are used, such as but not limited to: polytetrafluoroethylene (PTFE), reinforced polytetrafluoroethylene (RPTFE), or polyether ether ketone (PEEK), among others.

[0003] Conventional knife gate valve plastic seats include the following: molded plastic seats secured by pins welded to the valve body; molded plastic seats mounted on a stainless steel insert, where the stainless steel insert is secured by pins; molded plastic seats with a "D" profile and secured by a retainer; molded plastic seats secured by screws; and crimped plastic seats. However, these known resilient seats have several disadvantages. For example, certain conventional molded plastic seats are not securely fixed, especially when the gate is fully open. The cost of manufacturing is often high because known retainers and seats can require multiple manufacturing processes, including additional crimping, compression, welding, and the addition of pins, screws, O-rings, and other components. Assembly can be difficult (e.g., through a top or gland inlet) and replacement is difficult. For example, any welding to the seat makes replacement complex, and replacement kits often require multiple components as part of the seat assembly (e.g., can include a seat ring, a retainer, multiple fasteners, O-rings, etc.). Furthermore, certain known molded plastic seats can shift even when secured by pins or other securing devices within the valve body, rendering them unsuitable for reverse pressure or horizontal orientation installations. Additionally, conventional molded plastic seat designs that use O-ring support have an inherent temperature limit of 150 degrees Celsius (or 302 degrees Fahrenheit) or lower.

[0004] Therefore, knife gate valves require an improved resilient seat that can be securely fixed without additional fixing devices, mechanisms, fasteners, rings or screws; automatically lock or self-lock into the valve body or metal seat after insertion, without additional fixing devices or mechanisms; suitable for reverse pressure and for bidirectional valves; suitable for directions other than the standard vertical direction; and can be adapted to integral or separate valve seats. Summary of the Invention

[0005] The embodiments disclosed herein relate to a knife gate valve having a valve body defining an orifice and a gate for the orifice, and further comprising: an inner surface of the valve body; an annular groove completely defined within the inner surface; a stepped surface and a first locking surface defined within and on the annular groove, wherein the first locking surface is adjacent to and connected to the stepped surface; a resilient valve seat ring inserted into the annular groove, wherein the resilient valve seat ring has a wedge-shaped portion defining an inclined surface, and wherein the wedge-shaped portion is mounted through the stepped surface of the annular groove; a second locking surface defined on the resilient valve seat, wherein the second locking surface is adjacent to and connected to the inclined surface; and wherein the first locking surface and the second locking surface are configured to abut against each other. Attached Figure Description

[0006] By referring to the accompanying drawings, those skilled in the art can better understand these embodiments and clearly appreciate their numerous objects, features, and advantages. These drawings are for illustrative purposes only, illustrating typical embodiments of this disclosure, and should not be considered as limiting its scope, as this disclosure may contain other equally effective embodiments. For clarity and brevity, the drawings are not drawn to scale, and some features and views may be shown in an enlarged or schematic manner.

[0007] Figure 1 This is a front isometric sectional view of an exemplary embodiment of a knife gate valve with a resilient seat.

[0008] Figure 2 This is a side sectional view of an exemplary embodiment of a knife gate valve with a resilient seat.

[0009] Figure 3 An isometric view of an exemplary embodiment of a resilient valve seat for a knife gate valve.

[0010] Figure 4 An enlarged partial isometric sectional view of an exemplary embodiment of the valve body of a knife gate valve.

[0011] Figure 5 An enlarged partial isometric cross-sectional view of an exemplary embodiment of a resilient valve seat for a knife gate valve.

[0012] Figure 6A side sectional view of another exemplary embodiment of a two-way knife gate valve with two resilient valve seats.

[0013] Figure 7 for Figure 6 An enlarged partial side sectional view of another exemplary embodiment of a knife gate valve with two resilient valve seats.

[0014] Figure 8 This is a side sectional view of another exemplary embodiment of a one-way gate valve with a resilient seat.

[0015] Figure 9 An enlarged partial side sectional view of an exemplary embodiment of a knife gate valve with a resilient seat.

[0016] Figure 10 An enlarged partial side sectional view of an exemplary embodiment of a knife gate valve with a resilient seat.

[0017] Figure 11 A side view of the valve seat for an exemplary embodiment of a knife gate valve with a support ring.

[0018] Figure 12 This is a partial side sectional view of an exemplary embodiment of a knife gate valve with a support ring.

[0019] Figure 13 A side view of the valve seat for an exemplary embodiment of a knife gate valve with a gate guide or flange button.

[0020] Figure 14 A partial side sectional view of an exemplary embodiment of a knife gate valve with a gate guide or flange button. Detailed Implementation

[0021] The following description includes exemplary apparatus, methods, techniques, and sequences of instructions, all of which embody the technical aspects of the subject matter of this invention. However, it should be understood that the described embodiments can be practiced without these specific details.

[0022] Figure 1 A front isometric sectional view of an exemplary embodiment of a knife gate valve 10 for unidirectional media flow is shown, the knife gate valve having a plastic, resilient or flexible valve seat, a ring or valve seat ring 30; Figure 2A side sectional view is shown. The face-mounted knife gate valve 10 includes a valve body 20 defining an orifice 12 through which valve medium can flow when the valve 10 is in the open, partially open, or partially closed position. The valve body 20 may optionally include a metal or replaceable valve seat 21, wherein the metal valve seat 21 is fastened or otherwise secured to the valve body 20 and is replaceable. The orifice 12 may be a generally cylindrical surface or opening connecting the inner surface or end face 13 and the outer surface 14 of the valve body 20; alternatively, the orifice 12 may be a cylindrical surface or opening extending radially about an axis 15 along which medium can flow. When the valve 10 is in the fully closed position, a gate or plug 11 passes through the valve body 20 laterally or perpendicularly to the orifice 12 or the axis 15, blocking or blocking the entire orifice 12. When the valve 10 is in the fully open position, the gate 11 retracts above the valve body 20, and the orifice 12 is unobstructed. In the partially open or transitional position of the gate valve 10, the gate 11 may also partially cover the orifice 12. An actuator (not shown) or operator may drive the gate 11 to switch between the open and closed positions of the valve 10.

[0023] The inner surface 13 of the valve body 20 is always parallel to the gate 11 and is engraved or defined with an annular groove or slot 23, such as Figure 4 An enlarged isometric sectional view is shown. In some exemplary embodiments, for example... Figure 4 , 9 The knife gate valve 10, configured for unidirectional media flow as shown in Figure 10, may have an annular groove or slot 23 having a cross-sectional profile 22 defined as a stepped or uppercase "L" shaped profile, configured to engage with a flexible valve seat 30. In other exemplary embodiments, for example... Figures 6-7 The knife gate valve 10 shown is configured to or capable of enabling bidirectional media flow, and the profile 22 may further define an additional annular recess or compartment 41 for receiving an O-ring 40. In the embodiments described herein, the slot or groove 23 is entirely defined within a single component or assembly of the knife gate valve 10, which may be within the valve body 20 (e.g., see...). Figures 1-2 4, 9, and 10), or alternatively, a metal valve seat 21 fixed to and part of the valve body 20 (see, for example, see...). Figures 6-8 However, it can also be completely confined within another component of the gate valve 10. It is worth noting that the annular groove or slot 23 is integrally formed on the valve body 20, or integrally formed on the valve seat 21 as part of the valve body 20, but the groove or slot 23 is not formed or defined by a plurality of components, and the groove 23 is not formed between the valve body 20 and the valve seat 21.

[0024] The cross-sectional profile 22 of the groove 23 has at least three connected, integral, continuous surfaces, including: a stepped surface 24, an outermost groove surface 42, and a rear groove surface 29 connecting the stepped surface 24 and the outermost groove surface 42. The cross-sectional profile 22 may also optionally include an inclined surface 44 defined along the stepped surface 24 at the opening of the groove 23, connecting the valve seat surface 43 (or inner surface 13) of the valve body and the stepped surface 24 of the groove 23. The stepped surface 24 is radially closest to the bore axis 15 and includes a top stepped surface 25, which is a portion of a flat or planar surface that protrudes, extends, or projectes into the groove 23 and the profile 22. The stepped surface 24 also includes an inner locking surface 26 connected to and extending upward to the top stepped surface 25. The top stepped surface 25 is perpendicular to the inner locking surface 26 and preferably has no angle or inclination. The outermost groove surface 42 is the surface furthest from the hole axis 15 in the radial direction (surfaces 24, 29 and 42 of the annular groove 23), and is located opposite or opposite to the stepped surface 24.

[0025] The first end or region 27 of the annular groove or slot 23 may be directly adjacent to or abut against an opening toward the inner surface 13 of the valve body 20 (or the metal valve seat 21 which is part of the valve body 20), and further adjacent to the top stepped surface 25. The second end 28 of the annular groove or slot 23 includes the stepped descending portion of the groove 23 and is adjacent to the rear groove surface 42. Because of the stepped top surface 25 in the first end region 27, the first end region 27 may be narrower than the second end 28 (determined by the radial distance from the bore axis 15); the second end region 28 is wider because it includes the stepped descending portion of the groove 23.

[0026] Figure 3 An isometric view of an exemplary embodiment of the resilient valve seat 30 for the knife gate valve 10 is shown. Figure 5An enlarged partial isometric cross-sectional view of an exemplary embodiment of a resilient valve seat 30 for a knife gate valve 10 is shown. In some exemplary embodiments, the valve seat 30 may be made of a plastic material, but this disclosure also covers other flexible or resilient materials known to those skilled in the art. The resilient or flexible valve seat, ring, or valve seat ring 30 includes a flexible valve seat body 31 and a wedge portion 32 having an angled or inclined surface 36 extending, protruding, or projecting from the valve seat body 31. The flexible valve seat ring 30 includes or defines an inner surface 33 (on which the wedge portion 32 is located); an outer surface 34; a first end 37 connecting the outer surface 34 and the inclined / angled surface 36; and a second end 38 opposite the first end 37, which connects the inner surface 33 and the outer surface 34 of the flexible valve seat 30 and further engages with the gate 11 during assembly. The inclined surface 36 of the wedge portion 32 forms an angle or inlet angle 36a with an axis parallel to the bore axis 15, preferably between 10 and 15 degrees. The inclined surface 36 is also connected to or adjacent to the locking surface 35. The locking surface 35 is also defined on the inner surface 33 of the flexible valve seat 30. The various surfaces of the ring 30, including the inner surface 33, the outer surface 34, the first end 37, the second end 38, the inclined surface 36, and the locking surface 35, may appear to be composed of straight lines or planes when viewed in cross-section. The flexible, plastic, or resilient valve seat 30, including the valve seat body 31 and the wedge-shaped portion 32, may be constructed from an integral, monolithic, single, or one-piece assembly.

[0027] When installing the flexible or resilient valve seat ring 30, the first end 37 of the wedge 32 is first inserted toward the inner surface 13 and into the first end 27 of the annular groove 23. The specific angle 36a and inclined surface 36 of the wedge 32 allow it to be smoothly and efficiently installed onto the stepped top surface 25 of the ring 30 and inserted into the second end or stepped descending portion 28 of the groove 23. An optional inclined surface 44 of the groove 23 facilitates the rapid entry of the wedge 32 into the groove 23. The inclined surface allows the resilient valve seat 30 to be inserted into the groove 23, thus facilitating locking of the resilient valve seat 30. Once the wedge 32 is in the second end or stepped descending portion 28, the locking surface 35 of the ring 30 abuts, engages, or contacts the inner locking surface 26 of the groove 23. The locking surface 35 of the ring 30 and the locking surface 26 of the groove 23 allow the ring 30 to automatically secure or retain itself within the groove 23 without additional securing devices. Specifically, the stepped surface 24 can lock the valve seat 30, thereby preventing the valve seat 30 from moving outward when the gate 11 is fully closed or open, or partially open and partially closed. Furthermore, although the locking surfaces 26 and 35 shown in the figures are generally parallel to the gate 11, the valve seat surface 43 of the metal or replaceable valve seat 21 (or parallel to the inner surface 13 of the valve body 20), and perpendicular to the top surface 25, it should be understood that other angles of the locking surfaces 26 and 35 are also possible, and within the scope of this disclosure, the locking surfaces 26 and 35 can engage or abut against each other to prevent the plastic ring 30 from moving outward, provided that the wedge portion 32 is located at the second end of the groove 23 or the stepped descending portion 28.

[0028] exist Figures 9-10 In the exemplary embodiments shown, the gate engagement end 38 of the plastic or flexible valve seat 30 may be offset, positioned, or interleaved with the valve seat surface 43 or auxiliary engagement surface 43 of the valve body 20 or metal valve seat 21 by an offset distance 39. Specifically, the engagement end 38 of the resilient valve seat 30 extends a greater distance 39 in the direction of the gate 11 than the auxiliary engagement surface 43 of the valve body 20 or metal valve seat 21. The valve seat surface or auxiliary engagement surface 43 may be radially closer to or closer to the bore axis 15 than the engagement end 38 of the plastic valve seat 30. The presence of the offset distance 39 can be used in exemplary embodiments of the knife gate valve 10 with unidirectional or bidirectional media flow. Furthermore, in some exemplary embodiments, the offset distance 39 may be 0.5 mm, but may vary depending on the operational requirements of the valve 10. The offset distance 39 ensures that the gate 11 contacts the flexible valve seat 30 first; only after the flexible valve seat 30 wears down can the metal valve seat 21 (or valve body 20) contact the gate or closure 11. The offset distance 39 serves to protect the integrity of valve 10, because valve seat 30 will wear out first and is easier to replace than valve body 20 or metal valve seat 21.

[0029] Figures 6-7A side sectional view and enlarged view of an alternative exemplary embodiment of a face-seat knife gate valve 10 for bidirectional media flow are shown, the knife gate valve having two resilient valve seats 30. Figures 6-7 In this embodiment, an alternative exemplary model of the knife gate valve 10 may have two metal valve seats 21, each metal valve seat 21 may define a groove 23, and a flexible, resilient or plastic valve seat or ring 30 is inserted into each groove, which is consistent with the above. Figures 1-2 , Figure 4 and Figures 8-10 The groove 23 and valve seat 30 described herein are essentially similar. However, in Figures 6-7 In an exemplary embodiment, the groove profile 22 defines an additional annular recess or compartment 41 in its rear surface 29, into which an O-ring 40 can be inserted. Figures 6-7 An alternative exemplary embodiment of the bidirectional knife gate valve 10 may require pressure to be applied to the plastic valve seat 30, so an optional O-ring 40 provides the necessary pressure to the end 37 of the plastic or resilient valve seat 30.

[0030] The set range of angle 36a of the wedge portion 32, combined with locking surfaces 26 and 35, allows the flexible ring 30 to be quickly and efficiently installed into the groove 23. Furthermore, this embodiment allows the plastic or elastic ring 30 to achieve self-locking, fixation, or retention within the groove 23, eliminating the need for additional fixing devices such as screws, pins, retaining rings, adhesives, or welding as required by conventional knife gate valves, and restricting outward movement of the ring 30. The plastic ring 30 can snap into the groove 23 and lock immediately upon insertion. Additionally, angle 36a ensures smooth entry of the wedge portion 32 into the groove 23. Figures 11-14 As shown, the improved knife gate valve 10 and ring 30 are further adapted to reverse pressure (depending on the availability of the support ring 50 or gate guide / flange button 53) for knife gate valve 10 with unidirectional media flow in a first direction 51 and a second direction or reverse direction 52, wherein the second direction 52 is opposite to the first direction 51. The one-way valve 10 may have a preferred first flow direction 51 (i.e., downstream flow on one side of the valve seat 30). There may not be a preferred flow direction in the two-way valve 10. The two-way valve 10 may be a more suitable valve when reverse flow occurs frequently. However, in some cases, if the reverse pressure in the reverse direction 52 is low enough, the reverse pressure can be maintained by adding the support ring 50 or flange button 53, thus allowing the use of the one-way valve 10.

[0031] Since the groove 23 is integrally formed into the valve body 20 (or is a separate component of the valve body), the cost of machining the groove 23 can be reduced. Furthermore, since the flexible, plastic, or resilient valve seat 30 is also preferably constructed as an integral, one-piece component, its production cost is also reduced compared to conventional or known valve seats. It is worth noting that some conventional valve seats may require further processing, including crimping or compression steps, to incorporate additional components such as O-rings, while the improved valve seat 30 disclosed herein does not require these. Assembly in the prior art can also be more difficult, as it may require a conventional ring to enter from the top; in this disclosure, the improved ring 30 can be installed by lifting the gate 11 and inserting the ring 30 into the exposed inner surface 13. Another difference between the knife gate valve 10 disclosed in this invention and the prior art is that it does not require the use of any O-rings to achieve unidirectional media flow, and therefore can be applied to a higher temperature range than the prior art.

[0032] Furthermore, the groove 23 and ring 30 are capable and sufficient for the orientation of the knife gate valve 10 having a non-perpendicular stem direction. As shown, the combination of groove 23 and ring 30 can be used for integral valve seats (where groove 23 is defined in valve body 20) or separate valve seats (where groove 23 is defined in metal valve seat 21 connected to valve body), and is suitable for knife gate valves 10 with unidirectional or bidirectional media flow.

[0033] The offset distance 39 ensures that the gate 11 contacts the soft or flexible seat 30 first; only after the soft or flexible seat 30 wears out can the metal seat 21 (or valve body 20) contact the gate or closure 11. The offset distance 39 serves to protect the integrity of the valve body 20 or the metal seat 21 and extend its service life, as the seat 30 wears out first and is easier to replace than the valve body 20 or the metal seat 21. In conventional known valve seats, replacing any seat may require complex multi-component seat assembly and installation; however, in this exemplary embodiment, the knife gate valve 10 can typically be restored to normal operation simply by removing the original seat 30 and inserting the new seat 30. Therefore, the use of the improved groove 23 and the plastic, flexible, or resilient seat ring 30 overcomes many difficulties associated with conventional valve seats during circulation, including the inability to secure conventional seats, back pressure in the valve system, cost-effectiveness, ease of use and maintenance, and increased capability for use in horizontal and other non-vertical valve orientations.

[0034] While exemplary embodiments have been described with reference to various implementations and applications, it should be understood that these exemplary embodiments are for illustrative purposes only, and the scope of the invention is not limited thereto. Many variations, modifications, additions, and improvements can be made.

[0035] For a component, operation, or structure described as a single instance herein, multiple instances may be provided. Typically, structures and functionalities presented as independent components in exemplary configurations can be implemented as composite structures or components. Similarly, structures and functionalities presented as single components can also be implemented as independent components. These and other variations, modifications, additions, and improvements may fall within the scope of this invention.

Claims

1. A knife gate valve having a valve body defining an orifice for medium to flow along an orifice axis, and a gate for said orifice, and the knife gate valve comprising: The inner surface of the valve body; An annular groove that is completely confined within the inner surface of the valve body; Defined within an annular groove are a stepped surface and a first locking surface, wherein the first locking surface is adjacent to and connected to the stepped surface; An elastic valve seat ring inserted into an annular groove, wherein the elastic valve seat ring includes a wedge-shaped portion defining an inclined surface, wherein the wedge-shaped portion is mounted on a stepped surface passing through the annular groove. A second locking surface is defined within the resilient valve seat, wherein the second locking surface is adjacent to and connected to the inclined surface; and further, wherein the first locking surface and the second locking surface are configured to abut against each other.

2. The apparatus according to claim 1, wherein, The resilient valve seat ring also includes a resilient valve seat body, wherein the inclined surface of the wedge-shaped portion protrudes from the resilient valve seat body.

3. The apparatus according to claim 2, wherein, The resilient valve seat ring includes an engagement end for contacting the gate; and further, wherein the engagement end extends from the inner surface of the valve body toward the gate by an offset distance.

4. The apparatus according to claim 3, wherein, The angle of the inclined surface is set to 10 to 15 degrees.

5. The apparatus according to claim 4, wherein, The first locking surface and the second locking surface are perpendicular to the hole axis.

6. The apparatus according to claim 4, wherein, The annular groove is completely confined within the metal valve seat of the valve body.

7. The apparatus according to claim 4, wherein, The annular groove also includes an annular recess, and further includes an O-ring inserted into the annular recess.

8. The apparatus according to claim 7, wherein, The O-ring contacts the second end of the resilient valve seat ring, wherein the second end is opposite to the engagement end.

9. The apparatus according to claim 4, wherein, It also includes a ramp defined between the inner surface of the valve body and the stepped surface of the annular groove.

10. A method for assembling and using a knife gate valve, the knife gate valve having a valve body defining an orifice for medium flow about an orifice axis, and having a gate for said orifice, the method comprising the steps of: An annular groove is etched on the inner surface of the valve body, wherein the annular groove defines a stepped surface and a first locking surface; A flexible valve seat ring is provided, wherein a first end of the flexible valve seat ring has a wedge-shaped portion; The wedge-shaped portion of the flexible valve seat ring is inserted into the annular groove; and The flexible valve seat ring is automatically fastened into the annular groove.

11. The method of claim 10, further comprising the step of automatically preventing the flexible valve seat ring from moving outward from the annular groove when the gate is fully open or closed.

12. The method according to claim 11, wherein, The annular groove further defines a first locking surface adjacent to the stepped surface, and wherein the flexible valve seat ring further defines a second locking surface adjacent to the wedge-shaped portion; and further includes the step of engaging the first locking surface and the second locking surface.

13. The method according to claim 12, wherein, The wedge-shaped portion includes an inclined surface with an angle between 10 and 15 degrees.

14. The method according to claim 13, wherein, The annular groove is engraved on the metal seat of the valve body.

15. The method of claim 13, further comprising the step of: An O-ring is inserted into an annular groove, wherein the O-ring is adjacent to the first end of the flexible valve seat ring; and pressure is applied to the flexible valve seat ring through the O-ring.

16. The method according to claim 13, wherein, The second end of the flexible valve seat ring extends toward the gate and beyond the inner surface of the valve body by a certain offset distance.

17. The method of claim 16, further comprising the steps of engaging a second end of the flexible valve seat ring with a gate and separating the gate from the inner surface of the valve body by an offset distance.

18. The method of claim 13, further comprising the step of: The medium flows through the orifice in a first direction; and the medium flows through the orifice in a second direction, wherein the second direction is opposite to the first direction.

19. A knife gate valve having a valve body defining an outlet orifice along an axis of the orifice, and a gate operable between a closed position and an open position of the orifice, the knife gate valve comprising: The inner surface of the valve body; An annular groove includes a stepped surface, an outermost groove surface opposite to the stepped surface, and a rear groove surface connecting the stepped surface and the outermost groove surface, wherein the stepped surface, the outermost groove surface, and the rear groove surface are all limited only to the inner surface of the valve body. The stepped surface further defines a first locking surface; A resilient valve seat ring includes a resilient valve seat body and a wedge-shaped portion extending from the resilient valve seat body at a certain angle, and a second locking surface adjacent to the wedge-shaped portion; wherein the wedge-shaped portion of the resilient valve seat ring is inserted into an annular groove, and further wherein the resilient valve seat ring is fastened in the annular groove by engaging with a first locking surface and a second locking surface, thereby preventing the resilient valve seat ring from moving outward from the annular groove.

20. The apparatus according to claim 19, wherein, The angle is between 10 and 15 degrees.

21. The apparatus according to claim 20, wherein, The resilient valve seat ring can be secured in the annular groove without any fasteners, retaining rings or adhesives.

22. The apparatus according to claim 21, wherein, The annular groove further includes an annular compartment, wherein the annular compartment is also limited only to the inner surface of the valve body.

23. A valve seat ring for a knife gate valve, defining a generally cylindrical bore having a bore axis, the valve seat ring comprising: The plastic body of the valve seat ring; A wedge-shaped portion extending from the plastic body at an angle of 10 to 15 degrees; as well as A locking surface adjacent to the wedge-shaped portion, wherein the locking surface is perpendicular to the hole axis.

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