Valve body and self-actuating valve comprising said valve body

Abstract

A self-actuated valve includes a valve body (10) and a valve seat (28). The valve body includes: (i) a valve seat engaging portion; (ii) an elastomeric support portion; (iii) a circumferential nose; (iv) an upper closure member (92) having a lower surface (94) inclined toward the circumferential nose and a discharge opening; (v) an interior corner at which the elastomeric support portion is contiguous with the lower surface of the upper closure member; (vi) an elastomeric seal (54); and (vii) an expansion chamber. The elastomeric seal has (a) a lower outer contact surface, (b) an upper outer contact surface abutting against the lower surface (94) of the upper closure member (92) and extending beyond the circumferential nose, (c) an inner contact surface abutting against the lower surface (94) of the upper closure member (92) and extending beyond the circumferential nose. The inner contact surface is mounted as an interference fit on the elastomeric support portion and extends from the circumferential nose to at least 60% of the length of the elastomeric support portion and slides upward along the elastomeric support portion when the valve is closed.

Description

Field of the Invention

[0001] The present invention relates to a self-actuating valve. It also relates to a pump comprising the self-actuating valve. Background Art

[0002] One type of valve is a self-actuating valve. A self-actuating valve is designed to open when there is only a small pressure difference (e.g., less than 100 kPa (1 bar)) across the valve. This pressure difference only has to overcome the forces acting to close the valve, which are typically the force of gravity and the force of a spring that pushes the valve to the closed position. Different from an actuated valve that can open when there is a large pressure difference across the valve, a self-actuating valve has specific design constraints.

[0003] A particularly important aspect of a self-actuating valve is that the valve should close quickly to improve and the volumetric efficiency of a pump having the valve. Volumetric efficiency is the ratio of the actual flow rate provided by the pump to the theoretical discharge flow rate. It is an inherent characteristic of a self-actuating valve that the fluid flow has reversed before the valve closes. Any further delay in closing the valve reduces the volumetric efficiency of the pump.

[0004] Self-actuating valves have been around for decades, and there are many design variants of these valves.

[0005] A particularly challenging environment in which self-actuating valves operate is pumping slurries. A slurry is a two-phase fluid comprising solid particles suspended in a liquid, such as in a paste or as a settling slurry. A slurry typically has a solid concentration of at least 5 wt%. In valves, abrasive wear is usually the main type of wear (especially in the area where the valve seat meets the valve body), and it is particularly problematic when pumping slurries with relatively high solid concentrations of hard or abrasive particles. Self-actuating valves are not suitable for pumping pastes, such as slurries with a solid concentration higher than about 60 vol%.

[0006] When used in slurry pumping applications, prior art self-actuating valves comprising elastomeric seals have experienced problems. Due to the entrapment of slurry between the elastomeric seal and the elastomeric support portion of the valve body, high wear levels are experienced. When the valve closes and the pressure increases, this entrapped slurry is forced through the surface contact area between the elastomeric support portion and the elastomeric seal. This results in grooves at the intersection of the valve body and the valve seat, as well as grooves in the elastomeric support portion. These grooves in the elastomeric support portion reduce the effectiveness of the elastomeric support portion in supporting the elastomeric seal when the valve closes. This can lead to tearing, which appears as if the elastomeric seal has been chewed. At higher discharge pressures (e.g., at 8 MPa (80 bar) or higher) or larger valve diameters (e.g., 100 mm or higher), these two wear modes (grooving and chewing) are more severe and ultimately lead to valve rejection, which is a serious failure of the valve such that the valve can no longer prevent fluid from flowing through it.

[0007] These wear modes in a self-actuating valve with an elastomeric seal need to be avoided or mitigated.

[0008] One of the aims of embodiments of the present invention is to provide a device that can at least improve this problem or provide a useful alternative. SUMMARY OF THE INVENTION

[0009] The SUMMARY OF THE INVENTION is provided to introduce a series of concepts further described in the DETAILED DESCRIPTION below. The SUMMARY OF THE INVENTION is not intended to identify essential features of the claimed subject matter, nor is it intended to be used to assist in limiting the scope of the claimed subject matter.

[0010] In this application, ordinal numbers (first, second, third, etc.) are arbitrarily assigned herein and are used to distinguish parts and do not indicate a particular order, sequence, or importance.

[0011] According to a first aspect of the present invention, there is provided a self-actuating valve, comprising: a valve seat and a valve body for positioning in a flow path; the valve body defining a longitudinal axis and comprising: (i) a valve seat engaging portion at its lower part, the valve seat engaging portion extending radially outward at an angle, (ii) an elastomer support portion extending radially inward from an upper part of the valve seat engaging portion at an angle between 30 degrees and 40 degrees with respect to the longitudinal axis, (iii) a circumferential nose portion where the valve seat engaging portion and the elastomer support portion meet; (iv) an upper closing member having a lower surface inclined towards the circumferential nose portion at an angle between 0.5 degrees and 5 degrees with respect to a line perpendicular to the longitudinal axis and extending radially beyond the circumferential nose portion, the upper closing member defining a discharge port therein and extending through the discharge port; (v) an internal corner where the elastomer support portion and the lower surface of the upper closing member meet; (vi) an elastomer seal having: (a) a lower outer contact surface complementary to the valve seat and abutting against the valve seat when the valve body is in its closed position, (b) an upper outer contact surface abutting against the lower surface of the upper closing member and extending beyond the circumferential nose portion, (c) a central outer surface extending between the upper outer contact surface and the lower outer contact surface, and (d) an inner contact surface press-fitted onto the elastomer support portion and extending from the circumferential nose portion to at least 60% of the length of the elastomer support portion; and (vii) an expansion chamber defined by the lower surface of the upper closing member, the elastomer support portion, the internal corner and the elastomer seal, the expansion chamber being in fluid communication with the discharge port defined by the upper closing member, such that when the valve body is closed, the inner contact surface slides upward along the elastomer support portion and into the expansion chamber, while the upper outer contact surface resists sliding to substantially remain in place.

[0012] The protruding length (protruding elastomer support portion length) of the elastomer support portion includes the length from the circumferential nose portion to the point (intersection point) where the linear protrusion of the elastomer support portion meets the linear protrusion of the lower surface of the upper closing member. The intersection point may be behind (radially inward) the expansion chamber.

[0013] Optionally, the internal corner may define an arcuate cross-section. The arcuate cross-section may include a radius between 5% and 9% (in some embodiments, 7% and 8%) of the length of the protruding elastomeric support portion. In the case where the internal corner includes an angle equal to the angle between the elastomeric support portion and the lower surface of the upper closure member, then the internal corner is effectively a line, and the length of the protruding elastomeric support portion is approximately equal to the length of the actual elastomeric support portion.

[0014] The intersection point may be behind (radially inward) the internal corner.

[0015] Optionally, the lower surface of the upper closure member slopes towards the circumferential nose at an angle between 1 degree and 4 degrees, between 1.5 degrees and 3 degrees, or approximately 2.5 degrees with respect to a line perpendicular to the longitudinal axis.

[0016] Optionally, the seat engagement portion extends radially outward at an angle between 34 degrees and 36 degrees with respect to the longitudinal axis or at an angle of approximately 35 degrees with respect to the longitudinal axis.

[0017] Optionally, the elastomeric support portion extends radially inward from the upper portion of the seat engagement portion at an angle between 33 degrees and 37 degrees, between 34 degrees and 36 degrees, or at an angle of approximately 35 degrees with respect to the longitudinal axis.

[0018] The inner contact surface is defined as the portion of the elastomeric seal that contacts the elastomeric support portion.

[0019] Optionally, the inner contact surface extends at an angle (inner contact surface angle) that is slightly smaller (e.g., between 0.5 degrees and 4 degrees smaller) than the angle of the elastomeric support portion with respect to the longitudinal axis. This ensures a uniform contact stress through an interference fit between the inner contact surface and the elastomeric support portion. Optionally, the inner contact surface angle is between 30 degrees and 35 degrees with respect to the longitudinal axis or approximately 33 degrees with respect to the longitudinal axis. Providing a slightly smaller (than the elastomeric support portion angle) angle for the inner contact surface results in a uniform distributed contact stress; however, if the same angle as the elastomeric support portion angle is used for the inner contact surface, there will be a lower contact stress at the circumferential nose, which may cause particles to enter from the slurry (which will cause wear). Optionally, a higher range of inner contact surface angles is used for larger diameter elastomeric seals to ensure that the contact stress is not lower at the circumferential nose, which is where solid particles are prevented from entering.

[0020] Optionally, the elastomeric seal is prestressed (tensioned) due to being installed on the elastomeric support portion with an interference fit.

[0021] Optionally, the inner contact surface extends from the circumferential nose to at least 61%, 62%, 63%, 64%, 65%, 66%, 67%, 68%, 69%, 70%, 71%, 72%, 73%, 74%, 75%, 76%, 77%, 78%, 79%, 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, or 90% of the length of the elastomeric support portion (i.e., the distance from the circumferential nose to the starting point of the internal corner).

[0022] Optionally, the inner contact surface extends from the circumferential nose to at least 45% of the protruding length of the elastomeric support portion (which is the distance from the circumferential nose to the intersection point).

[0023] Optionally, the inner contact surface extends from the circumferential nose to at least 45%, 46%, 47%, 48%, 49%, 50%, 51%, 52%, 53%, 54%, 55%, 56%, 57%, 58%, 59%, 60%, 61%, 62%, 63%, 64%, 65%, 66%, 67%, 68%, 69%, or 70% of the protruding length of the elastomeric support portion (which is the distance from the circumferential nose to the intersection point).

[0024] The upper closing member may include a nut screwed onto the stem of the valve body or a cap bolted (or otherwise fixed) to the top of the valve body. Alternative types of upper closing members may be used.

[0025] Optionally, the valve seat engagement portion angle is between 30 degrees and 60 degrees with respect to the longitudinal axis, in some embodiments between 30 degrees and 40 degrees with respect to the longitudinal axis, and in other embodiments between 33 degrees and 36 degrees with respect to the longitudinal axis.

[0026] The portion of the elastomeric seal that contacts the lower surface of the upper closing member and is radially farthest from the longitudinal axis may be referred to as the "distal upper contact point".

[0027] The upper outer contact surface is defined as the portion of the elastomeric seal that contacts the lower surface of the upper closing member. The portion of the upper outer contact surface that contacts the lower surface of the upper closing member and is radially closest to the longitudinal axis may be referred to as the "proximal upper contact point".

[0028] The portion of the elastomeric seal that contacts the inner contact surface of the elastomeric seal and is radially closest to the longitudinal axis may be referred to as the "proximal inner contact point".

[0029] Optionally, when the valve is in the open position, the upper outer contact surface extends radially beyond the circumferential nose by at least 2%, at least 2.5%, or at least 3%. These percentages relate to the comparison of the radial width of the distal upper contact point to the radial width of the circumferential nose.

[0030] The circumferential nose may also be referred to as the tip.

[0031] The distance from the intersection point to the distal upper contact point may be referred to as the "projecting upper seal length".

[0032] Optionally, the length of the upper outer contact surface is at least 30% of the projecting upper seal length.

[0033] Optionally, the length of the upper outer contact surface is between 30% and 60%, between 32% and 50%, or between 32% and 45% of the projecting upper seal length.

[0034] Optionally, the length of the inner contact surface is at least 45% of the projecting elastomeric support portion length.

[0035] Optionally, the length of the inner contact surface is between 45% and 50%, between 51% and 56%, or between 57% and 60% of the projecting elastomeric support portion length.

[0036] Optionally, the elastomeric seal defines an arcuate surface between the upper outer contact surface and the inner contact surface. The arcuate surface may include a convex surface. The arcuate surface may include a radius between 15% and 25% (in some embodiments, 18% and 21%) of the projecting elastomeric support portion length.

[0037] Optionally, the expansion chamber defines a generally crescent shape in cross-section.

[0038] Optionally, the expansion chamber defines a projecting upper length along the lower surface of the upper closure member to the intersection point, and a projecting lower length along the elastomeric support portion toward the intersection point.

[0039] Optionally, the projecting upper length of the expansion chamber is at least 35%, 40%, 50%, 60%, 65%, 66%, 67%, 68%, 69%, 70%, 71%, 72%, 73%, 74%, 75%, 76%, 77%, 78%, 79%, 80%, 85%, or 88% longer than the length of the upper outer contact surface.

[0040] Optionally, the ratio of the projecting lower length of the expansion chamber to the length of the inner contact surface is between 0.56 and 0.79, between 0.62 and 0.69, between 0.63 and 0.68, or between 0.64 and 0.68.

[0041] Optionally, the ratio of the length of the upper outer contact surface to the length of the inner contact surface is between 0.2 and 0.3, between 0.22 and 0.28, or between 0.23 and 0.27.

[0042] (i) The combination of features of an elastomeric seal that is prestressed (tensioned) due to being press-fitted onto an elastomeric support portion and extending from a circumferential nose to at least 60% of the length of the elastomeric support portion and (ii) an upper outer contact surface that abuts the lower surface of the upper closure member and extends beyond the circumferential nose results in the generation and maintenance of contact stress of the elastomeric seal at the elastomeric support portion. This ensures a tight fit between the elastomeric seal and the elastomeric support portion. This tight fit prevents or at least greatly reduces the entry of particles into the fluid flowing through the flow path between the inner contact surface and the elastomeric support portion. This tight fit minimizes the amount of fluid trapped when the valve is closed. This trapped fluid is extruded during pressure build-up (when the valve is closed). This extrusion creates a high flow rate in the mating contact surfaces (i.e., the inner contact surface and the elastomeric support portion on which the inner contact surface is mounted). If the inner contact surface and the elastomeric support portion do not maintain tight contact, the high flow rate of the particles will create erosion grooves in the inner contact surface or the elastomeric support portion. These grooves will increase over successive cycles of the valve as the volume of corroded material increases. This will result in the elastomeric support portion being unable to support the elastomeric seal characteristics, ultimately leading to the damage and failure of the elastomeric seal and the valve. By preventing or reducing the entry of such particles, the wear of the elastomeric seal or the elastomeric support portion is greatly reduced. The absence of wear means that the volume between the elastomeric seal and the elastomeric support portion does not increase (since wear removes material from these surfaces). This greatly reduces the generation of erosion grooves therein, thereby greatly reducing the failure modes of the valve body.

[0043] At least 60% of the length of the elastomeric seal extending from the circumferential nose to the elastomeric support portion has the advantage that the friction between the inner contact surface and the elastomeric support portion makes it difficult to deform the elastomeric seal into the expansion chamber. In particular, the annular shape of the elastomeric seal makes it difficult to deform radially. Making the angle between the elastomeric support portion and the longitudinal axis between 33 degrees and 37 degrees makes it easier to deform the elastomeric seal into the expansion chamber. The combination of this deformation into the expansion chamber, the angle of the elastomeric support portion, and the small downward angle of the lower surface of the upper closure member also ensures a minimum of sliding on the lower surface of the upper closure member, with limited lateral expansion on each side of the upper outer contact surface. This combination ensures that longitudinal forces are applied mainly at the upper outer contact surface, thus ensuring a minimum of sliding of the elastomer on the upper closure member. Conversely, there is limited lateral expansion of the upper outer contact surface (a relatively large percentage increase in the surface area of the elastomeric seal in contact with the lower surface of the upper closure member). This greatly reduces the ingress of particles and thus reduces erosion and wear.

[0044] Optionally, the upper outer contact surface comprises: (i) a central static portion that does not move relative to the lower surface of the upper closure member as the valve moves from the open position to the closed position, and (ii) lateral sliding portions on both sides of the central static portion.

[0045] Optionally, the lateral expansion of the upper outer contact surface is between 0.5 mm and 10 mm. More specifically, the lateral expansion of the upper outer contact surface can be between 0.5 mm and 5 mm. It should be understood that the lateral expansion can vary depending on how the elastomeric seal deforms, which can change due to wear of the elastomeric seal, the valve seat, and the elastomeric support portion. The lateral expansion is also affected by the resistance of the fluid in the expansion chamber to flow out of the chamber through the discharge port. A fluid with a high viscosity in the discharge port and / or the chamber, having a high resistance to flow out of the chamber (such as a slurry), will limit the inward lateral expansion, resulting in an increased outward lateral expansion of the upper outer contact surface. The total deformation of the elastomeric seal over its entire cross-section ensures low additional stress and strain. The deformation is spread over the entire cross-section of the seal. If one attempts this with prior art designs (e.g., clamped valve rings), local high stress and strain will lead to tearing and premature failure of the valve.

[0046] One advantage of fluidly connecting the expansion chamber to the discharge port is that when the valve is closed, it allows the elastomeric seal to deform into the expansion chamber. Generally, it also allows pressure equalization on both sides of the elastomeric seal, as the usually higher pressure region above the valve is in fluid communication with the expansion chamber. In cases where small particles prevent the valve from closing completely, it also ensures that the elastomeric seal moves to the correct sealing position by means of the pressure difference between the high-pressure side and the low-pressure side.

[0047] The valve seat can include an integral part of a support (such as a housing) or a detachable part that can be replaced when worn.

[0048] The valve seat can be annular and arranged around the flow path such that the flow path extends therethrough. When the valve body is in the closed position, the valve seat can have a higher pressure side and a lower pressure side, and the diameter of the valve seat can decrease from the higher pressure side towards the lower pressure side over at least a portion of its length. In one embodiment, the valve seat is frustoconical in shape and has a constant cone angle from its higher pressure side to its lower pressure side.

[0049] The elastomeric seal can be formed as an integral molding or casting of an elastomeric material such as polyurethane rubber. Any other convenient elastomeric material can be used for molding the elastomeric seal, such as styrene-butadiene rubber (SBR), ethylene propylene diene monomer (EPDM) rubber, fluorocarbon elastomer (FKM) rubber, nitrile butadiene rubber (NBR), or hydrogenated acrylonitrile butadiene rubber (HNBR), depending on the slurry being pumped and the temperature.

[0050] The test results of the valve manufactured according to the first aspect have shown unexpectedly good results. It was recorded that the valve life was extended by at least 33%. Different from the previous valve designs, the elastomeric seal is not a limiting factor in the overall valve life, thus extending the valve life.

[0051] According to a second aspect of the present invention, there is provided a self-actuating valve body for use with a valve seat, the valve body comprising: (i) a valve seat engaging portion at its lower part, the valve seat engaging portion extending radially outwardly at an angle, (ii) an elastomer support portion extending radially inwardly from an upper part of the valve seat engaging portion at an angle between 30 degrees and 40 degrees with respect to the longitudinal axis, (iii) a circumferential nose where the valve seat engaging portion meets the elastomer support portion, (iv) an upper closing member having a lower surface inclined towards the circumferential nose at an angle between 0.5 degrees and 5 degrees with respect to a line perpendicular to the longitudinal axis and extending radially beyond the circumferential nose, the upper closing member defining a discharge port therein and extending through the discharge port; (v) an internal corner where the elastomer support portion meets the lower surface of the upper closing member; (vi) an elastomer seal having: (a) a lower outer contact surface complementary to the valve seat and abutting the valve seat when the valve body is in its closed position, (b) an upper outer contact surface abutting the lower surface of the upper closing member and extending beyond the circumferential nose, (c) a central outer surface extending between the upper outer contact surface and the lower outer contact surface, and (d) an inner contact surface press-fitted onto the elastomer support portion and extending from the circumferential nose to at least 60% of the length of the elastomer support portion; and (vii) an expansion chamber defined by the lower surface of the upper closing member, the elastomer support portion, the internal corner, and the elastomer seal, the expansion chamber being in fluid communication with the discharge port defined by the upper closing member such that when the valve body is closed, the inner contact surface slides upwardly along the elastomer support portion and into the expansion chamber while the upper outer contact surface resists sliding to remain substantially in place.

[0052] Optionally, the elastomer seal is prestressed (tensioned) by being press-fitted onto the elastomer support portion.

[0053] Optionally, the upper outer contact surface resists sliding and restricts lateral expansion at each side of the upper outer contact surface.

[0054] According to a third aspect of the present invention, there is provided a pump comprising one or more self-actuating valves according to the first aspect of the present invention.

[0055] According to a fourth aspect of the present invention, there is provided a self-actuating valve, which includes: a valve seat and a valve body, the valve body being adapted to be positioned in a flow path; the valve body defining a longitudinal axis and including: (i) a valve seat engaging portion at its lower part, the valve seat engaging portion extending radially outward at an angle, (ii) an elastomer support portion, the elastomer support portion extending radially inward from an upper part of the valve seat engaging portion at an angle between 30 degrees and 40 degrees with respect to the longitudinal axis, (iii) a circumferential nose, the valve seat engaging portion and the elastomer support portion meeting at the circumferential nose; (iv) an upper closing member, the upper closing member having a lower surface and extending radially beyond the circumferential nose, the upper closing member defining a discharge port therein and extending through the discharge port; (v) an internal corner, the elastomer support portion and the lower surface of the upper closing member meeting at the internal corner; (vi) an elastomer seal, the elastomer seal having: (a) a lower outer contact surface, the lower outer contact surface being complementary to the valve seat and abutting against the valve seat when the valve body is in its closed position, (b) an upper outer contact surface, the upper outer contact surface abutting against the lower surface of the upper closing member and extending beyond the circumferential nose, (c) a central outer surface, the central outer surface extending between the upper outer contact surface and the lower outer contact surface, and (d) an inner contact surface, the inner contact surface being press-fitted onto the elastomer support portion and extending from the circumferential nose to at least 60% of the length of the elastomer support portion; and (vii) an expansion cavity, the expansion cavity being defined by the lower surface of the upper closing member, the elastomer support portion, the internal corner and the elastomer seal, the expansion cavity being in fluid communication with the discharge port defined by the upper closing member, such that when the valve body is closed, the inner contact surface slides upward along the elastomer support portion and into the expansion cavity, while the upper outer contact surface resists sliding to substantially remain in...

[0056] Optionally, the upper outer contact surface resists sliding and restricts lateral expansion at each side of the upper outer contact surface.

[0057] It should be understood that the angles selected within the above ranges have been shown to provide significantly improved performance of the valve, especially when used for pumping slurries. BRIEF DESCRIPTION OF THE DRAWINGS

[0058] These and other aspects of the present invention will now be described by way of example with reference to the accompanying drawings, in which:

[0059] Figure 1 is a cross-sectional front view of a self-actuating valve according to an embodiment of the present invention, wherein the valve is in a closed position;

[0060] Figure 2 is Figure 1 a front cross-sectional view of a valve, where the valve is in the open position;

[0061] Figure 3 is Figure 1 a perspective view of the valve body of;

[0062] Figure 4 is Figure 3 a front cross-sectional view of the valve body of;

[0063] Figure 5 is Figure 3 a perspective view of the valve body of, but with a part (the elastomeric seal) removed;

[0064] Figure 6 is Figure 5 a front cross-sectional view of the valve body of, where the elastomeric seal is removed;

[0065] Figure 7 is an enlarged cross-sectional view of the elastomeric seal (with the central part removed for clarity);

[0066] Figure 8 is Figure 2 an enlarged view of a part of the valve of, showing the parts in more detail; and

[0067] Figure 9 is Figure 1 a graphical view of a part (the elastomeric seal) under three different conditions (not installed, installed with the valve open, installed with the valve closed). DETAILED DESCRIPTION

[0068] Reference will now be made to the drawings, where reference numeral 10 indicates a self-actuating valve according to an embodiment of the present invention. The self-actuating valve 10 defines a longitudinal axis 12 and includes a housing, a part of which is shown in the drawings and is generally indicated by reference numeral 20. A first fluid port, generally indicated by numeral 22 (an inlet in this embodiment), and a second fluid port, generally indicated by numeral 24 (an outlet in this embodiment), are each defined by the housing 20, and a flow path extends through the housing 20 and connects the fluid ports 22, 24 in fluid communication. In this embodiment, the inlet 22 is oriented transversely (perpendicularly) to the outlet 24. In Figure 1 the outlet 24 is actually formed by the part of the housing 20 that has been removed to show the cross-section.

[0069] The housing 20 defines a chamber 26 through which fluid, particularly a slurry containing particles, is conveyed from the inlet 22 to the outlet 24. In this embodiment, the solid concentration of the slurry is approximately 35 wt%.

[0070] The valve 10 further includes a valve seat, generally designated by reference numeral 28, positioned between the two fluid ports 22, 24. In one embodiment, the valve seat 28 may be formed by a hardened surface in the housing. In another embodiment shown in the drawings, the valve seat 28 is formed by an insert mounted on the housing 20, which facilitates replacement of the valve seat 28 in case of wear. A pair of elastomeric O-rings 30 are located between the valve seat 28 and the housing 20. A fluid passage 32 is provided to allow hydraulic fluid to assist in removing the valve seat 28 when needed.

[0071] The valve seat 28 is a conventional annular valve seat and defines a part of the flow path. The valve seat 28 includes a frustoconical upper portion 40 having a narrow end 42 and a wider end 44, and a generally cylindrical lower portion 46 extending downward from the narrow end 42 of the frustoconical portion 40. In other embodiments, the valve seat 28 may have different shapes.

[0072] The valve 10 further includes a valve body 50, which includes: a central body portion 52; a valve ring (in the form of an elastomeric seal in this embodiment) 54 press-fitted onto the central body portion 52; and alignment legs 56 extending downward from the central body portion 52 to assist in centering the valve body 50 when the valve 10 is opened and closed. In this embodiment, the alignment legs 56 are friction welded to the central body portion 52. In this embodiment, the central body portion 52 is a one-piece cast component, but in other embodiments, it may include separable components and may be manufactured using other techniques than casting, such as forging, and connected using any convenient technique (such as welding).

[0073] A valve housing cover 60 is provided to enclose the chamber 26 above the valve body 50. The clamping plate portion 62 defines (i) a support portion 64 mounted to the lower side of the valve housing cover 60, and (ii) a cylindrical guide 66 extending downward from the support portion 64 and generally centered thereon. The cylindrical guide 66 defines a central guide channel 68 and an outer cylindrical surface 70 therein. The central guide channel 68 is in fluid communication with the chamber 26. A wear-resistant cylindrical guide bushing 72 is press-fitted at the entrance of the central guide channel 68. A helical spring 74 is mounted around the outer cylindrical surface 70. In other embodiments, the cylindrical guide bushing 72 may be installed and held in place by a snap ring.

[0074] The central body portion 52 defines a cylindrical rod portion 80 extending upward along the longitudinal axis 12. The cylindrical rod portion 80 is located within the central guide channel 68 and is in sliding contact with the cylindrical guide bushing 72. The lower portion of the helical spring 74 contacts the upper portion of the central body portion 52. The helical spring 74 is selected to prevent the valve body 50 from opening until a desired pressure differential is reached.

[0075] As Figure 4 and 6 best seen in, the central body portion 52 defines a valve seat engaging portion 82 at its lower portion, the valve seat engaging portion radially extending outwardly at an angle 84 between 30 degrees and 40 degrees with respect to a line parallel to the longitudinal axis 12. In this embodiment, the angle 84 is approximately 35 degrees, but in other embodiments, the valve seat engaging portion angle 84 can be greater, such as between 40 degrees and 60 degrees.

[0076] The central body portion 52 also defines an elastomer support portion 86, the elastomer support portion radially extending inwardly at an angle 88 between 30 degrees and 40 degrees with respect to a line parallel to the longitudinal axis 12 from an upper portion of the valve seat engaging portion 82. In this embodiment, the angle 88 is approximately 35 degrees.

[0077] The valve seat engaging portion 82 meets the elastomer support portion 86 at a circumferential nose (also referred to as a tip) 90.

[0078] The central body portion 52 also defines an upper closure member 92, the upper closure member having a lower surface 94 that slopes toward the circumferential nose 90 at an angle 96 between 0.5 degrees and 5 degrees with respect to a line perpendicular to the longitudinal axis 12 (best seen in Figure 8 ). The upper closure member 92 extends radially beyond the circumferential nose 90 and defines a discharge port 98 therein and extends therethrough (best seen in Figures 3 to 6 ). In this embodiment, the angle 96 is approximately 2.5 degrees. Although the upper closure member 92 is shown in the figures as an integral part of the valve body 52, in other embodiments, the upper closure member 92 can be a separable component, such as a cap or nut having threads or other securing mechanisms.

[0079] As Figure 7 best seen in, the elastomeric seal 54 has a lower outer contact surface 100 that is complementary to the valve seat 28 and abuts the valve seat when the valve body 50 is in its closed position. The lower outer contact surface 100 extends at an angle (approximately 35 degrees in this embodiment) that is substantially the same as the valve seat engaging portion angle 84, but radially projects beyond the tip 90 (e.g., a few millimeters, such as 3 mm) to ensure sealing engagement of the lower outer contact surface 100 with the valve seat 28 when the valve 10 is in the closed position. This projection is best seen in Figure 8 .

[0080] The elastomeric seal 54 also has an upper outer contact surface 102 that abuts the lower surface 94 of the upper closure member 92 and extends beyond the circumferential nose 90 when the valve is in the open position, by at least 2% in this embodiment.

[0081] The central outer surface 104 extends between the upper outer contact surface 102 and the lower outer contact surface 100.

[0082] The elastomeric seal 54 also has an inner contact surface 106 and a convex expansion surface 108 that extends between the upper outer contact surface 102 and the inner contact surface 106. The inner contact surface angle 109 is a few degrees smaller (about 2 degrees smaller in this embodiment) than the elastomeric support portion angle 88, such that the elastomeric seal 54 is an interference fit with uniform contact stress around the central body portion 52, and the elastomeric seal 54 is prestressed (tensioned) due to being installed on the central body portion 52 as an interference fit. The inner contact surface 106 is defined as the portion of the elastomeric seal 54 that contacts the elastomeric support portion 86. The deformation of the elastomeric seal 54 can cause the inner contact surface 106 to slightly grow or shrink.

[0083] As Figure 4 and 8 best seen in, the expansion cavity 110 is defined by the lower surface 94 of the upper closure member 92, the elastomeric support portion 86, and the elastomeric seal 54 (specifically its convex expansion surface 108). The expansion cavity 110 is in fluid communication with one side of the discharge port 98. The other side of the discharge port 98 leads into the chamber 26.

[0084] Now referring specifically to Figure 9 , which shows how the elastomeric seal 54 changes shape during installation and during operation of the valve 10. Figure 9 The shape shown in is particularly applicable to the elastomeric seal when the elastomeric seal 54 is new rather than after a long period of use, but Figure 9 the general changes shown in are still valid for the worn elastomeric seal 54.

[0085] Before the elastomeric seal 54 is installed on the central body portion 52, the seal 54 has the shape shown by the dashed line 112. Once the seal 54 has been installed on the central body portion 52, its shape changes mainly by moving radially outward, but also by moving downward along the upper outer contact surface 102, as shown by the dashed line 114. This results in an increase in the diameter of the elastomeric seal 54.

[0086] When the valve body 50 is closed, the seal 54 has the shape shown by the dashed line 116. Closing the valve body 50 causes the valve seat 28 to exert an upward force on the elastomeric seal 54, which causes the lower outer contact surface 100 to move upward and radially inward, sliding upward along the elastomeric support portion 86. The upper outer contact surface 102 has limited lateral expansion at each side and expands only a limited amount laterally inward (into the expansion cavity 110) and laterally outward along the lower surface 94 at its edges, which results in along the central portion of the upper outer contact surface 102 (i.e., Figure 9The negligible movement (without slipping over the length of the lower surface 94) of the portion shown by the double arrow 120 in [the figure]. The central outer surface 104 moves radially outward by a relatively small amount. The inner contact surface 106 moves upward and into the expansion chamber 110 by sliding upward along the elastomeric support portion 86. The convex expansion surface 108 moves radially inward and upward into the expansion chamber 110. When this occurs, any slurry (or other pumped fluid) or air trapped in the expansion chamber 110 passes through the discharge port 98 into the chamber 26. Thus, due to the configuration of the central body portion 52 and the elastomeric seal 54, when the valve 10 is closed and the elastomeric seal 54 is compressed, the inner contact surface 106 slides upward along the elastomeric support portion 86 and into the expansion chamber 110; while the upper outer contact surface 102 resists sliding along the lower surface 94 of the upper closure member 92 and remains substantially in place at each of its sides, with limited lateral expansion. In this embodiment, the lateral expansion of the upper outer contact surface 102 is between 0.5 mm and 10 mm inwardly in the lateral direction, and between 0.5 mm and 5 mm outwardly in the lateral direction. The limited lateral expansion results in a limited percentage increase in the surface area of the elastomeric seal in contact with the lower surface of the upper closure member. It should be understood that the lateral expansion can vary based on how the elastomeric seal deforms, which can change due to wear of the elastomeric seal, the valve seat, and the elastomeric support portion.

[0087] The lateral expansion is also affected by the resistance to the flow of fluid in the expansion chamber 110 out of the chamber 110 through the discharge port 98. A fluid with a high viscosity in the expansion chamber 110, which has a high resistance to flow out of the chamber (such as slurry), will limit the inward lateral expansion, causing the upper outer contact surface 102 to have an increased outward lateral expansion.

[0088] One reason to prevent or at least reduce wear is that the main wear mode of the valve is abrasive wear, and three components must be present for abrasive wear to occur: an abrasive (particles present in the slurry), pressure (the elastomeric seal 54 is compressed), and movement (although the upper outer contact surface 102 expands at its edges, it does not slip).

[0089] By closing the valve 10, the elastomeric seal 54 is compressed (its outer height decreases), and solid particles in the slurry can be trapped between the valve seat 28 and the lower outer contact surface 100 (and embedded in the lower outer contact surface 100). When the valve 10 is closed, there is usually also a pressure difference. This differential pressure tends to extrude the elastomeric seal 54 into the lower pressure portion (usually below the circumferential nose 90).

[0090] When the valve body 50 is closed but remains in contact with the circumferential nose 90, the elastomeric seal 54 slides in a radially inward direction; whereas prior art designs provide movement only in the longitudinal direction and lose contact with the equivalent of the circumferential nose 90. This means that in those prior art designs, when the valve 10 is closed in the presence of a pressure differential, the equivalent of the lower outer contact surface 100 slides more (in this embodiment, more than the lower outer contact surface 100).

[0091] Now referring specifically to Figure 8 , which shows the various dimensions of the valve body 50.

[0092] The elastomeric support portion 86 meets the lower surface 94 of the upper closure member 92 at the internal corner 122. In this embodiment, the internal corner has an arcuate cross-section, as best seen in Figure 8 . The arcuate cross-section defines a radius of less than 10 mm, but in other embodiments, a different radius (or a different shape, such as an angled corner) may be selected.

[0093] The intersection point 124 is the point where the line projecting from the elastomeric support portion 86 meets the line projecting from the lower surface 94 of the upper closure member 92. The intersection point 124 is behind the internal corner 122 (radially inward from the internal corner). However, for clarity, the distance between the internal corner 122 and the intersection point 124 is enlarged in Figure 8 .

[0094] The upper outer contact surface 102 is defined as the portion of the elastomeric seal 54 that contacts the lower surface 94 of the upper closure member 92. The point on the upper outer contact surface 102 that is radially farthest from the longitudinal axis 12 is the distal upper contact point 126; and the point that is radially closest to the longitudinal axis 12 is the proximal upper contact point 128.

[0095] The point on the inner contact surface 106 that is radially closest to the longitudinal axis 12 is the proximal inner contact point 130.

[0096] The distance from the intersection point 124 to the radially farthest point of the upper closure member 92 is the upper member length (shown by arrow 140).

[0097] The distance from the intersection point 124 to the distal upper contact point 126 is the protruding upper seal length (shown by arrow 142). The distance from the distal upper contact point 126 to the proximal upper contact point 128 is the upper outer contact surface length (shown by arrow 146, which approximates this length).

[0098] In this embodiment, the upper outer contact surface length 146 is at least 20% of the protruding upper seal length 142. In other embodiments, the upper outer contact surface length 146 may be less than 40% of the protruding upper seal length 142.

[0099] The distance from the intersection point 124 to the proximal upper contact point 128 is the protruding upper length of the expansion chamber (shown by arrow 144). In this embodiment, the protruding upper length 144 of the expansion chamber is at least 150% longer than the upper outer contact surface length 146. In other embodiments, the protruding upper length 144 of the expansion chamber may be longer by a percentage greater than 150%. Optionally, the protruding upper length 144 of the expansion chamber is at least 200% longer than the upper outer contact surface length 146. Optionally, the protruding upper length 144 of the expansion chamber is at least 250% longer than the upper outer contact surface length 146. Optionally, the protruding upper length 144 of the expansion chamber is at least 300% longer than the upper outer contact surface length 146.

[0100] The distance from the intersection point 124 to the circumferential nose 90 is the protruding elastomeric support portion length (shown by arrow 148), even though the portion between the internal corner 122 and the intersection point 124 is not available to support the inner contact surface 106 of the elastomeric seal 54. In this embodiment, the inner contact surface 106 extends from the circumferential nose 90 along at least 45% of the protruding elastomeric support portion length 148. In other words, in this embodiment, the ratio of the inner contact surface length 150 to the elastomeric support portion length 148 is at least 0.45. In other embodiments, the inner contact surface 106 may further extend along the elastomeric support portion length 148, for example, at a ratio of at least 0.55.

[0101] The actual (non-protruding) elastomeric support portion length 151 is the length from the circumferential nose 90 to the starting point of the internal corner 122.

[0102] The distance from the circumferential nose 90 to the proximal inner contact point 130 is the inner contact surface length (shown by arrow 150). In this embodiment, the ratio of the upper outer contact surface length 146 to the inner contact surface length 150 is between 0.2 and 0.3; but in other embodiments, a larger range may be used, for example, between 0.15 and 0.35.

[0103] The distance from the circumferential nose 90 to the longitudinal axis 12 is the tip diameter (shown by arrow 152). The distance from the distal upper contact point 126 to the longitudinal axis 12 is the elastomeric seal diameter (shown by arrow 154). In this embodiment, the ratio of the elastomeric seal diameter 154 to the tip diameter 152 is approximately 1.03. In other embodiments, this ratio may be selected from the range between 1.01 and 1.05.

[0104] The distance from the intersection point 124 to the proximal inner contact point 130 is the lower length of the expansion chamber protrusion (shown by arrow 156). In this embodiment, the ratio of the lower length 156 of the expansion chamber protrusion to the inner contact surface length 150 is approximately 0.79. In other embodiments, different ratios may be selected, such as a ratio between 0.7 and 0.85.

[0105] In this embodiment, the inner contact surface 106 extends circumferentially from the circumferential nose 90 along at least 60% of the elastomeric support portion 86. In other words, in this embodiment, the ratio of the inner contact surface length 150 to the elastomeric support portion length 151 is at least 0.6. In other embodiments, the inner contact surface 106 may extend further along the elastomeric support portion 86, for example, at a ratio of the inner contact surface length 150 to the elastomeric support portion length 151 of at least 0.7.

[0106] During operation of the valve 10 (when the valve 10 is oriented as Figure 1 and 2 shown), as the pressure at the inlet 22 increases, the pressure difference across the valve body 50 increases. Once the pressure at the inlet 22 exceeds the gravitational and spring forces, the valve body 50 moves upward and fluid flows through the valve 10 until the pressure difference decreases and the force of the helical spring 74 is greater than the pressure difference, at which point the valve body 50 moves downward and the valve 10 closes.

[0107] The above-described valve 10 can be used in any convenient application, such as in a positive displacement pump. The valve 10 can be used as an inlet valve or an outlet valve in any convenient orientation.

[0108] Various modifications can be made to the embodiments described above within the scope of the present invention. For example, many of the dimensions and ratios given above include ranges from which values can be selected; different values from each of these ranges can be used to produce embodiments, thus providing a very large number of unique embodiments.

[0109] In other embodiments, the valve 10 can be installed in the opposite orientation (i.e., inverted) or at an angle to that Figure 1 and 2 shown. If installed inverted, gravity will assist in opening the valve 10.

[0110] List of reference numerals

[0111] Self-actuating valve 10

[0112] Longitudinal axis 12

[0113] Housing 20

[0114] First fluid port (inlet) 22

[0115] Second fluid port (outlet) 24

[0116] chamber 26

[0117] valve seat 28

[0118] O - ring 30

[0119] hydraulic fluid passage 32

[0120] frustoconical upper portion 40

[0121] narrow end (of frustoconical upper portion) 42

[0122] wider end (of frustoconical upper portion) 44

[0123] cylindrical lower portion 46

[0124] valve body 50

[0125] central body portion (of valve body) 52

[0126] valve ring (elastomeric seal) 54

[0127] alignment leg (of valve body) 56

[0128] valve housing cover 60

[0129] clamping plate portion 62

[0130] support portion (of clamping plate portion) 64

[0131] cylindrical guide (of clamping plate portion) 66

[0132] central guide channel (of cylindrical guide) 68

[0133] outer cylindrical surface (of cylindrical guide) 70

[0134] cylindrical guide bushing (of cylindrical guide) 72

[0135] helical spring 74

[0136] cylindrical rod portion (of central body portion) 80

[0137] valve seat engagement portion 82

[0138] valve seat engagement portion angle 84

[0139] elastomeric support portion 86

[0140] elastomeric support portion angle 88

[0141] circumferential nose (or tip) 90

[0142] upper closing member (of central body portion) 92

[0143] Lower surface 94 (of the upper closing member)

[0144] Angle 96 (of the upper closing member)

[0145] Discharge port 98 (in the upper closing member)

[0146] Lower outer contact surface 100 (of the valve ring)

[0147] Upper outer contact surface 102 (of the valve ring)

[0148] Central outer surface 104 (of the valve ring)

[0149] Inner contact surface 106 (of the valve ring)

[0150] Convex expansion surface 108 (of the valve ring)

[0151] Inner contact surface angle 109

[0152] Expansion cavity 110

[0153] Seal - not - installed shape 112

[0154] Seal - installed shape 114

[0155] Closing - seal shape 116

[0156] Central part 120 (of the upper outer contact surface)

[0157] Internal corner 122

[0158] Intersection point 124

[0159] Distal upper contact point 126

[0160] Proximal upper contact point 128

[0161] Proximal inner contact point 130

[0162] Upper - member length 140

[0163] Projecting upper - seal length 142

[0164] Expansion - cavity projecting upper length 144

[0165] Upper - outer contact - surface length 146

[0166] Projecting elastomer - support - part length 148

[0167] Inner - contact - surface length 150

[0168] Elastomer - support - part length 151

[0169] Tip diameter 152

[0170] Elastomeric seal diameter 154

[0171] Expansion cavity protruding lower length 156

Claims

1. A self-actuating valve, comprising: a valve seat, and a valve body configured to be positioned in a flow path; the valve body defining a longitudinal axis and comprising: (i) a valve seat engagement portion at its lower part, the valve seat engagement portion extending radially outwardly at an angle to the longitudinal axis; (ii) an elastomeric support portion extending radially inwardly from an upper part of the valve seat engagement portion at an angle between 30 degrees and 40 degrees to the longitudinal axis; (iii) a circumferential nose portion where the valve seat engagement portion and the elastomeric support portion meet; (iv) an upper closure member having a lower surface that is inclined towards the circumferential nose portion at an angle between 0.5 degrees and 5 degrees to a line perpendicular to the longitudinal axis and radially extends beyond the circumferential nose portion, the upper closure member defining a discharge port therein and extending through the discharge port; (v) an internal corner where the elastomeric support portion and the lower surface of the upper closure member meet; (vi) an elastomeric seal having (a) a lower outer contact surface that is complementary to the valve seat and abuts the valve seat when the valve body is in its closed position, (b) an upper outer contact surface that abuts the lower surface of the upper closure member and extends beyond the circumferential nose portion, (c) a central outer surface extending between the upper outer contact surface and the lower outer contact surface, and (d) an inner contact surface that is press-fitted onto the elastomeric support portion and extends from the circumferential nose portion to at least 60% of the length of the elastomeric support portion; and (vii) an expansion chamber defined by the lower surface of the upper closure member, the elastomeric support portion, the internal corner, and the elastomeric seal, the expansion chamber being in fluid communication with the discharge port defined by the upper closure member such that when the valve body is closed, the inner contact surface slides upwardly along the elastomeric support portion and into the expansion chamber while the upper outer contact surface resists sliding to remain substantially in place.

2. The valve according to claim 1, wherein the internal corner defines an arcuate cross-section having a radius of less than 10 mm.

3. The valve according to claim 1 or 2, wherein the lower surface of the upper closure member is inclined towards the circumferential nose portion at an angle of less than four degrees to a line perpendicular to the longitudinal axis.

4. The valve according to any one of the preceding claims, wherein the elastomeric seal is prestressed due to being press-fitted onto the elastomeric support portion.

5. The valve according to any one of the preceding claims, wherein the upper outer contact surface expands laterally between 0.5 mm and 10 mm on each of its sides.

6. The valve according to claim 5, wherein the lateral expansion of the upper outer contact surface increases the surface area of the elastomeric seal in contact with the lower surface of the upper closing member.

7. The valve according to any one of the preceding claims, wherein the inner contact surface extends at an angle to the longitudinal axis that is between 0.5 degrees and 4 degrees greater than the elastomeric support portion angle.

8. The valve according to any one of the preceding claims, wherein the inner contact surface extends from the circumferential nose to at least 65% of the length of the elastomeric support portion.

9. The valve according to any one of the preceding claims, wherein when the valve is in the open position, the upper outer contact surface extends radially beyond the circumferential nose by at least 2%.

10. The valve according to any one of the preceding claims, wherein the length of the upper outer contact surface is at least 20% of the length of the protruding upper seal.

11. The valve according to any one of the preceding claims, wherein the length of the inner contact surface is at least 45% of the length of the protruding elastomeric support portion.

12. The valve according to any one of the preceding claims, wherein the elastomeric seal defines an arcuate surface between the upper outer contact surface and the inner contact surface.

13. The valve according to any one of the preceding claims, wherein the expansion chamber defines a generally crescent shape in cross-section.

14. The valve according to any one of the preceding claims, wherein the upper protruding length of the expansion chamber is at least 150% longer than the length of the upper outer contact surface.

15. The valve according to any one of the preceding claims, wherein the ratio of the lower protruding length of the expansion chamber to the length of the inner contact surface is between 0.7 and 0.

85.

16. The valve according to any one of the preceding claims, wherein the ratio of the length of the upper outer contact surface to the length of the inner contact surface is between 0.2 and 0.

3.

17. A pump comprising one or more self-actuating valves according to any one of claims 1 to 16.

18. A self-actuating valve body for use with a valve seat, the valve body comprising: (i) a valve seat engaging portion at its lower part, the valve seat engaging portion extending radially outwardly at an angle to the longitudinal axis; (ii) an elastomeric support portion extending radially inwardly from an upper part of the valve seat engaging portion at an angle between 30 degrees and 40 degrees to the longitudinal axis; (iii) a circumferential nose, where the valve seat engaging portion and the elastomeric support portion meet at the circumferential nose; (iv) an upper closing member having a lower surface that is inclined towards the circumferential nose at an angle between 0.5 degrees and 5 degrees to a line perpendicular to the longitudinal axis and extends radially beyond the circumferential nose, the upper closing member defining a discharge port therein and extending through the discharge port; (v) an internal corner, where the elastomeric support portion and the lower surface of the upper closing member meet at the internal corner; (vi) an elastomeric seal having (a) A lower outer contact surface, which is complementary to the valve seat and abuts against the valve seat when the valve body is in its closed position. (b) An upper outer contact surface, which abuts against the lower surface of the upper closing member and extends beyond the circumferential nose. (c) A central outer surface, which extends between the upper outer contact surface and the lower outer contact surface, and (d) An inner contact surface, which is press-fitted onto the elastomeric support portion and extends from the circumferential nose to at least 60% of the length of the elastomeric support portion. And (vii) An expansion cavity, which is defined by the lower surface of the upper closing member, the elastomeric support portion, the internal corner, and the elastomeric seal, and is in fluid communication with the discharge port defined by the upper closing member, such that when the valve body is closed, the inner contact surface slides upward along the elastomeric support portion and into the expansion cavity, while the upper outer contact surface resists sliding to substantially remain in.

19. The self-actuating valve body according to claim 18, wherein the elastomeric seal is prestressed due to being press-fitted onto the elastomeric support portion.

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