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CA-3273955-C - SELF-ACTUATED VALVE

CA3273955CCA 3273955 CCA3273955 CCA 3273955CCA-3273955-C

Abstract

ABSTRACT A self-actuated valve includes a valve body (10) and seat (28). The valve body comprises: (i) a seat engagement portion; (ii) an elastomer support portion; (iii) a circumferential nose; (iv) an upper closing member (92) having a lower surface (94) inclined towards the circumferential nose and a vent; (v) an internal corner where the elastomer support portion and the lower surface of the upper closing member meet; (vi) an elastomeric seal (54); and (vii) an expansion cavity. The elastomeric seal has (a) a lower external contact surface, (b) an upper external contact surface abutting against the lower surface (94) of the upper closing member (92) and extending beyond the circumferential nose, (c) an internal contact surface mounted on the elastomer support portion as an interference fit and extending from the circumferential nose to at least 60% of the length of the elastomer support portion and sliding up the elastomer support portion on valve closure.

Inventors

  • Johannes Stroeken

Assignees

  • WEIR MINERALS NETHERLANDS B.V.

Dates

Publication Date
20260505
Application Date
20240105
Priority Date
20230117

Claims (5)

  1. WO 2024/154011 22 PCT/IB2024/050103 22 CLAIMS 1. A self-actuated 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 seat engagement portion at a lower part thereof extending radially outwards at an angle to the longitudinal axis; (ii) an elastomer support portion extending from an upper portion of the seat engagement portion radially inwards at an angle of between 30 and 40 degrees to the longitudinal axis; (iii) a circumferential nose at which the seat engagement portion meets the elastomer support portion; (iv) an upper closing member having a lower surface inclined towards the circumferential nose at an angle of between 0.5 and 5 degrees to a line perpendicular to the longitudinal axis, and extending radially beyond the circumferential nose, the upper closing member defining a vent therein and extending therethrough; (v) an internal corner where the elastomer support portion and the lower surface of the upper closing member meet; (vi) an elastomeric seal having (a) a lower external contact surface complementary to and abutting against the valve seat when the valve body is in its closed position, (b) an upper external contact surface abutting against the lower surface of the upper closing member and extending beyond the circumferential nose, (c) a central external surface extending between the upper external contact surface and the lower external contact surface, and (d) an internal contact surface mounted on the elastomer support portion as an interference fit and extending from the circumferential nose to at least 60% of the length of the elastomer support portion; and (vii) an expansion cavity defined by the lower surface of the upper closing member, the elastomer support portion, the internal corner, and the5 23 23 elastomeric seal, the expan^.. cavity being in fluid communication with the vent defined by the upper closing member so that when the valve body closes, the internal contact surface slides up the elastomer support portion and into the expansion cavity, whereas the upper external contact surface resists sliding to remain substantially in place.
  2. 2. The valve as claimed in claim 1 , wherein the internal corner defines an arcuate cross-section having a radius of less than 10 mm.
  3. 3. The valve as claimed in claim 1 or 2, wherein the lower surface of the upper closing member is inclined towards the circumferential nose at an angle to a line perpendicular to the longitudinal axis of less than four degrees.
  4. 4. The valve as claimed in any preceding claim, wherein the elastomeric seal is pre-stressed as a result of being mounted on the elastomer support portion as an interference fit. 5. The valve as claimed in any preceding claim, wherein the upper external contact surface expands laterally at each side thereof between 0.5mm and 10mm. 6. The valve as claimed in claim 5, wherein the lateral expansion of the upper external contact surface increases the surface area of the elastomeric seal that is in contact with the lower surface of the upper closing member. 7. The valve as claimed in any preceding claim, wherein the internal contact surface extends at an angle to the longitudinal axis between 0.5 and 4 degrees larger than the elastomer support portion angle. 8. The valve as claimed in any preceding claim, wherein the internal contact surface extends from the circumferential nose to at least 65% of the length of the elastomer support portion. 9. The valve as claimed in any preceding claim, wherein the upper external contact surface extends radially beyond the circumferential nose by at least 2% when the valve is in the open position. 10. The valve as claimed in any preceding claim, wherein the length of the upper external contact surface is at least 20% of a projected upper seal length.
  5. 5 WO 2024/154011 24 PCT/IB2024/050103 24 11. The valve as claimed in any precec... claim, wherein the length of the internal contact surface is at least 45% of a projected elastomer support portion length. 12. The valve as claimed in any preceding claim, wherein the elastomeric seal defines an arcuate surface between the upper external contact surface and the internal contact surface. 13. The valve as claimed in any preceding claim, wherein the expansion cavity defines a generally crescent shape in cross-section. 14. The valve as claimed in any preceding claim, wherein an expansion cavity projected upper length is longer than the length of the upper external contact surface by at least 150%. 15. The valve as claimed in any preceding claim, wherein a ratio of an expansion cavity projected lower length to the length of the internal contact surface is between 0.7 and 0.85. 16. The valve as claimed in any preceding claim, wherein the ratio of the length of the upper external contact surface to the length of the internal contact surface is between 0.2 and 0.3. 17. A pump including one or more self-actuated valves according to any of claims 1 to 16. 18. A self-actuated valve body for use with a valve seat, the valve body comprising: (i) a seat engagement portion at a lower part thereof extending radially outwards at an angle to the longitudinal axis; (ii) an elastomer support portion extending from an upper portion of the seat engagement portion radially inwards at an angle of between 30 and 40 degrees to the longitudinal axis; (iii) a circumferential nose at which the seat engagement portion meets the elastomer support portion; (iv) an upper closing member having a lower surface inclined towards the circumferential nose at an angle of between 0.5 and 5 degrees to a line perpendicular to the longitudinal axis, and extending radially beyond the5 WO 2024/154011 PCT/IB2024/050103 circumferential nose, the upr~. closing member defining a vent therein and extending therethrough; (v) an internal corner where the elastomer support portion and the lower surface of the upper closing member meet; (vi) an elastomeric seal having (a) a lower external contact surface complementary to and abutting against the valve seat when the valve body is in its closed position, (b) an upper external contact surface abutting against the lower surface of the upper closing member and extending beyond the circumferential nose, (c) a central external surface extending between the upper external contact surface and the lower external contract surface, and (d) an internal contact surface mounted on the elastomer support portion as an interference fit and extending from the circumferential nose to at least 60% of the length of the elastomer support portion; and (vii) an expansion cavity defined by the lower surface of the upper closing member, the elastomer support portion, the internal corner, and the elastomeric seal, the expansion cavity being in fluid communication with the vent defined by the upper closing member so that when the valve body closes, the internal contact surface slides up the elastomer support portion and into the expansion cavity, whereas the upper external contact surface resists sliding to remain substantially in. 19. The self-actuated valve body as claimed in claim 18, wherein the elastomeric seal is pre-stressed as a result of being mounted on the elastomer support portion as an interference fit.

Description

WO 2024/154011 1 PCT/IB2024/050103 VALVE BODY AND SELF-ACTUATED VALVE COMPRISING SAID VALVE BODY FIELD OF INVENTION This invention relates to a self-actuated valve. It also relates to a pump including that self-actuated valve. 5 BACKGROUND OF THE INVENTION One type of valve is a self-actuated valve. A self-actuated valve is designed to open when there is only a small pressure differential across the valve, such as less than 100 kPa (1 bar). This pressure differential only has to overcome the force acting to close the valve, which is typically gravitational force and the force of a spring that io urges the valve to the closed position. Unlike actuated valves, that can open when there is a large pressure difference across the valve, a self-actuated valve has specific design constraints. One particularly important aspect of a self-actuated valve is that the valve should close quickly to improve the volumetric efficiency of the pump incorporating the 15 valve. The volumetric efficiency is the ratio of the actual flow rate that the pump delivers to the theoretical discharge flow rate. An inherent feature of a self-actuated valve is that the flow of fluid is already reversed before the valve is closed. Any further delay in closing the valve lowers the volumetric efficiency of the pump. Self-actuated valves have been available for many decades, and there are 20 many design variations of these valves. One particularly challenging environment for self-actuated valves to operate in is in pumping slurries. Slurries are two-phase fluids that include solid particles suspended in liquid, for example, as a paste or as a settling slurry. Slurries typically have a solids concentration of at least 5% by weight. In valves, abrasive wear is 25 typically the dominant wear type (particularly at the area where the valve seat meets the valve body), and is particularly problematic when pumping slurries having a relatively high solids concentration of hard or abrasive particles. Self-actuated valves are not suitable for use in pumping pastes, such as slurries having a solids concentration above approximately 60% by volume. 30 Prior art self-actuated valves that include an elastomeric seal have had problems when used in slurry pumping applications. High levels of wear are experienced as a result of trapped slurry between the elastomeric seal and the elastomer support portion of the valve body. When the valve is closed, and theWO 2024/154011 PCT/IB2024/050103 2 2 pressure rises, this trapped slurry is force^ ....ough the surface contact area between the elastomer support portion and the elastomeric seal. This results in grooves at the intersection of the valve body and the valve seat, and grooves in the elastomer support portion. These grooves in the elastomer support portion reduce the effectiveness of 5 the elastomer support portion in supporting the elastomeric seal when the valve is closed. This can cause tearing, which looks like nibbling of the elastomeric seal. These two wear patterns (grooving and nibbling) are more severe at higher discharge pressures (e.g. at 8 MPa (80 Bar) or above) or larger valve diameters (e.g. 100 mm or above), and eventually cause valve wash-out, which is critical failure of the valve such io that the valve can no longer prevent fluid flow therethrough. It is desirable to obviate or mitigate these wear patterns in self-actuated valves having elastomeric seals. It is among the objects of an embodiment of this invention to provide means which may at least ameliorate this problem or provide a useful alternative. 15 SUMMARY OF THE INVENTION This summary is provided to introduce a selection of concepts that are further described in the detailed description below. This summary is not intended to identify indispensable features of the claimed subject matter, nor is it intended for use as an aid in limiting the scope of the claimed subject matter. 20 In this application ordinal numbers (first, second, third, etc.) are assigned arbitrarily herein, and are used to differentiate between parts, and do not indicate a particular order, sequence, or importance. According to a first aspect of the invention there is provided a self-actuated valve comprising: a valve seat and a valve body for positioning in a flow path; the valve 25 body defining a longitudinal axis and comprising: (i) a seat engagement portion at a lower part thereof extending radially outwards at an angle, (ii) an elastomer support portion extending from an upper portion of the seat engagement portion radially inwards at an angle of between 30 and 40 degrees to the longitudinal axis, (iii) a circumferential nose at which the seat engagement portion meets the elastomer 30 support portion (iv) an upper closing member having a lower surface inclined towards the circumferential nose at an angle of between 0.5 and 5 degrees to a line perpendicular to the longitudinal axis, and extending radially beyond the circumferential nose, the upper closing member def