Valve assembly

Abstract

The disclosure relates to valve assemblies having a valve body including a first port, a second port and a fluid passageway extending therebetween. A valve member, having a through port, is arranged in the fluid passageway and is moveable between an open and closed positions. A sealing arrangement is arranged between the first port and the valve member and includes a sealing member arranged to seal against the valve member such that fluid cannot flow around an outer surface of the valve member. The sealing arrangement includes a sleeve arranged in the fluid passageway between the first port and the valve member. A deformable, incompressible, medium is contained around the sleeve and arranged such that, in use, a fluid within the sleeve exerts an outward pressure on the sleeve causing the sleeve to deform and act on the medium to push the sealing member against the valve member.

Claims

1. A valve assembly comprising: a valve body comprising a first port, a second port and a fluid passageway extending between the first and second ports; a valve member, comprising a through port, arranged in the fluid passageway and moveable between an open position in which a fluid can flow between the first and second ports through the through port, and a closed position in which the fluid cannot flow between the first and second ports; and a sealing arrangement, arranged between the first port and the valve member, comprising: a sealing member arranged to seal against the valve member such that the fluid cannot flow around an outer surface of the valve member; a sleeve arranged in the fluid passageway between the first port and the valve member; and a deformable, incompressible, medium contained around the sleeve and arranged such that, in use, the fluid within the sleeve exerts an outward pressure on the sleeve causing the sleeve to deform and act on the medium which applies a force to push the sealing member against the valve member.

2. The valve assembly as claimed in claim 1, wherein the valve member comprises a rotatable ball valve member.

3. A valve assembly as claimed in claim 2, further comprising a resilient member arranged to resiliently bias the sealing member into contact with the valve member.

4. A valve assembly as claimed in claim 1, further comprising a resilient member arranged to resiliently bias the sealing member into contact with the valve member.

5. A valve assembly as claimed in claim 1, wherein the sealing member extends around a portion of the sleeve, and wherein said portion of the sleeve adjacent the sealing member is configured such that it does not deform under fluid pressure in the sleeve.

6. A valve assembly as claimed in claim 5, wherein a stiffening band is arranged around the portion of the sleeve adjacent the sealing member such that said portion cannot deform.

7. A valve assembly as claimed in claim 1, comprising a first sealing element arranged between the sealing member and the sleeve.

8. A valve assembly as claimed in claim 7, comprising a second sealing element arranged between the sealing member and the valve body.

9. A valve assembly as claimed in claim 1, comprising a second sealing element arranged between the sealing member and the valve body.

10. A valve assembly as claimed in claim 1, wherein the medium is inserted into the valve assembly under pressure.

11. A valve assembly as claimed in claim 1, wherein the sleeve comprises a corrugated structure.

12. A valve assembly as claimed in claim 1, wherein the medium is contained within a cavity, defined by the valve body, around the sleeve.

13. A valve assembly as claimed in claim 12, wherein the sealing member defines a first end of the cavity, and a second end of the cavity is defined by a fixed wall.

14. A valve assembly as claimed in claim 1, wherein the medium is grease.

15. A valve assembly as claimed in claim 1, wherein the medium is oil.

16. A valve assembly as claimed in claim 1, comprising a further sealing arrangement arranged between the second port and the valve member, the further sealing arrangement comprising: a further sealing member arranged to seal against the valve member such that the fluid cannot flow around the outer surface of the valve member; a further sleeve arranged in the fluid passageway between the second port and the valve member; and a further deformable, incompressible, medium contained around the further sleeve and arranged such that, in use, the fluid within the further sleeve exerts an outward pressure on the further sleeve causing the further sleeve to deform and act on the further medium which applies a force to push the further sealing member against the valve member.

17. A valve assembly as claimed in claim 1, comprising at least one further port and at least one further fluid passageway connecting the further port to another port.

18. A valve assembly as claimed in claim 1, wherein the sealing member is made from polytetrafluoroethylene.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) Certain examples of the present disclosure will now be described with reference to the accompanying drawings, in which:

(2) FIG. 1 is a sectional view of a valve assembly in accordance with an example of the present disclosure;

(3) FIG. 2 is a sectional view focusing on the first port of the valve assembly shown in FIG. 1;

(4) FIG. 3 is a sectional view focusing on the engagement of the sealing arrangement with the valve member shown in FIG. 1;

(5) FIG. 4 is a side view of the sleeve in isolation;

(6) FIG. 5 is a sectional view through the line A-A in the sleeve shown in FIG. 4;

(7) FIG. 6 is a sectional view of the valve assembly shown in FIG. 1, with the valve member in a closed position;

(8) FIG. 7 is a sectional view of a valve assembly which comprises three ports in accordance with another example of the present disclosure;

(9) FIG. 8 is a sectional view of a valve assembly which comprises four ports in accordance with a further example of the present disclosure; and

(10) FIG. 9 is a sectional view of a valve assembly which does not comprise a resilient member in accordance with a further example of the present disclosure.

DETAILED DESCRIPTION

(11) FIG. 1 is a sectional view of a valve assembly 2 in accordance with an example of the present disclosure. The valve assembly 2 comprises a valve body 4 comprising a first port 6, a second port 8 and a fluid passageway 10 extending between the first and second ports 6, 8. A valve member 12 is arranged in the fluid passageway 10. The valve member 12 comprises a through port 14 extending through the body of the valve member 12. In the example shown, the valve member 12 is in the form of a rotatable ball valve member. The valve assembly 2 may thus be considered to be a ball valve. However, any other suitable valve member 12 may be used. The valve member 12 is moveable, in this example rotatable, between an open position (as shown in FIG. 1) in which fluid can flow between the first and second ports 6, 8 and a closed position (shown in FIG. 6), in which fluid cannot flow between the first and second ports 6, 8.

(12) Which of the first and second ports 6, 8 is considered to be an input port or an output port, depends on the direction of fluid flow through the valve assembly 2. For example, if fluid enters the valve assembly 2 via the first port 6, the first port 6 may be considered to be an inlet port, and the second port 8 may be considered to be an outlet port. Conversely, if fluid enters the valve assembly via the second port 8, the second port 8 may be considered to be an inlet port, and the first port 6 may be considered to be an outlet port.

(13) The valve assembly 2 further comprises a sealing arrangement 15A which acts to seal the fluid passageway 10 around the valve member 12. The sealing arrangement 15A prevents fluid, which is in the fluid passageway 10, escaping around an outer surface of the valve member 12. The sealing arrangement 15A comprises a sealing member 16 arranged to seal against an outer surface the valve member 16 such that fluid cannot flow around an outer surface of the valve member. The shape of the sealing member 16 may depend on the shape 12 of the through port 14 in the valve member 12 and the shape of the fluid passageway 10. The through port 12 and fluid passageway 10 may have a circular cross section and thus the sealing member 16 may have a complimentary ring shape such that the sealing member 16 can extend around the through port 12 as depicted in FIG. 1. The sealing member 16 may be made from any suitable material that can provide a sufficient seal, for example polytetrafluoroethylene (PTFE).

(14) The sealing arrangement 15A also comprises a sleeve 18 arranged in the fluid passageway 10. The sleeve 18 is a hollow cylinder which permits the flow fluid therethrough. The sleeve 18 therefore partially defines the fluid passageway 10 through the valve assembly 2. The sleeve 18 is arranged between the first port 6 and the valve member 12. In the example shown, the sleeve 18 comprises a corrugated structure. This is shown more clearly in FIGS. 4 and 5.

(15) FIG. 4 shows a view of the sleeve 18 in isolation and FIG. 5 shows an cross-sectional view through the line A-A shown in FIG. 4. With reference to FIGS. 4 and 5, the sleeve 18 is in the form of a hollow cylinder and has an outer profile formed of a plurality of corrugations 44. As will be described in more detail below, the corrugations allow the sleeve 18 to expand more easily under the influence of fluid pressure within the sleeve 18. Any number of corrugations 44 may be provided, and the particular shape of the corrugations 44 may be chosen so as to control how the sleeve 18 deforms/expands under fluid pressure.

(16) Referring back to FIG. 1, a deformable, incompressible medium 20 is arranged around the sleeve 10. The medium 20 is contained within a cavity 21 which is at least partially defined by the sleeve 18 and the valve body 4. A lowermost portion of the cavity 21 is defined by the sealing member 16 which closes one end of the cavity 21. The uppermost end of the cavity 21 is defined by a fixed wall 23. In the example shown, the fixed wall 23 is provided by a fixing element 24, which will be described in more detail below with respect to FIG. 2. The sealing member 16 may be considered to translate, at least to a small degree, within the cavity 21 so as to be forced into contact with the valve member 12. In the example shown, the sealing member 16 is restricted such that it can move along the direction towards the valve member 12.

(17) The medium 20 may be any suitable material which is deformable and incompressible such that it efficiently transfers the force imparted upon it by the expanding sleeve 18. The medium 20 may, for example, comprise grease or oil.

(18) A resilient member 22, in the form of a coiled spring, is also arranged in the cavity 21, and is arranged to resiliently bias the sealing member 16 into contact with the valve member 12. The resilient member 22 abuts against the fixed wall 23 at one end and against the sealing member 16 at the other end 16. When the valve assembly 2 is assembled, the resilient member 22 may be configured such that it applies a resilient bias to the sealing member 16 when no fluid is in, or passing through, the valve assembly 2. This advantageously ensures that a high quality seal is formed around the valve member 16 even when the low fluid pressure in the valve assembly 2 is low, i.e. when the fluid pressure is too low to cause deformation of the sleeve 18.

(19) With reference to FIG. 1 and FIG. 2, which shows the upper end of the valve assembly in more detail, the upper end of the cavity 21 is closed by the fixed wall 23 of the fixing element 24. A first fixing element seal 26 is arranged between the fixing element 24 and the valve body 4 so as to prevent the outflow of the medium 20 from the cavity 21. A second fixing element seal 28 is arranged between the sleeve 18 and the fixing element 24. This acts to prevent the outflow of the medium 20 into the fluid passageway 10 and also prevent the flow of fluid within the fluid passageway 10 into the cavity 21. The first fixing element seal 26 and the second fixing element seal 28 may be in the form of O-ring seals.

(20) In the example shown, the fixing element 24 also functions to secure the sleeve 18 to the valve body 4. A lip 42 of the sleeve 18 is sandwiched between the fixing element 24 and a port member 40 which defines the input port 6. Whilst not visible, the fixing element 24 comprises a threaded portion and the port member 40 comprises a corresponding threaded portion which engage with one another to hold port member 40 in engagement with the fixing element 24. The fixing element 24 is held to the valve body 4 via screws (not shown).

(21) FIG. 3 shows the sealing member 16 in contact with the valve member 12 in more detail. With reference to both FIGS. 1 and 3, a first sealing element 30 is arranged between the sealing member 16 and the sleeve 18 to prevent the outflow of the medium 20 into the fluid passageway and also prevent the flow of fluid in the fluid passageway 10 into the cavity 21 wherein the medium 20 is contained. A second sealing element 32 is arranged between the sealing member 16 and the valve body 4. This prevents the outflow of the medium 20 out of the cavity and around an outer surface 34 of the valve member 12. The first sealing element 30 and second sealing element 32 may all be in the form of O-ring seals.

(22) In the example depicted, the sealing member 16 extends around a portion 36 of the sleeve 18. A portion 36 of the sleeve 18 adjacent the sealing member 16 is configured such that it does not deform under fluid pressure in the sleeve 18. In the example depicted, this is achieved through the presence of a stiffening band 38 provided around the sleeve 18 in the portion 36 adjacent the sealing member 16 such that said portion 36 cannot deform. The stiffening band 38 may be formed of a material which is stiffer, i.e. more resistant to deformation, than the rest of the sleeve 18. The stiffening band 38 may also be integrally provided with the sleeve 18. For example, the stiffening band 38 may be formed by folding of the sleeve in the portion 36.

(23) It will be appreciated that whilst both the medium 20 and resilient member 22 are shown as acting directly on the sealing member 16, an intermediate member may be provided between the sealing member 16 and the medium and resilient member 22. Any suitable intermediate member may be used.

(24) Referring back to FIG. 1, the valve assembly 2 comprises a further sealing arrangement 15B which is arranged between the second port 8 and the valve member 12. The further sealing arrangement 15B is identical to the sealing arrangement 15A discussed above and functions in an identical manner.

(25) As mentioned above, FIG. 6 shows a sectional view of the valve assembly 2 shown in FIG. 1, with the valve member 12 in the closed position as shown. In the closed position, the through port 14 of the valve member 12 is no longer aligned with the fluid passageway 10 and thus fluid can no longer flow between the first port 6 and second port 8. When the valve member 12 is in the closed position, the sealing arrangements 15A, 15B, seal around the valve member 12 and such that fluid cannot escape around the valve member 12.

(26) Operation of the valve assembly 2 will now be described with reference to FIGS. 1 to 6. Sealing within the valve assembly 2 will be described in detail with respect to sealing arrangement 15A, but it should be understood that the same applies to the further sealing arrangement 15B. With the valve member 12 in the open position, as shown in FIG. 1, fluid can freely flow between the first and second ports 6, 8. In the example shown in FIG. 1, for illustrative purposes, the first port 6 is functions as an inlet port and the second port 8 is functioning as an outlet port. The arrows 46 show the direction of fluid flow through the fluid passageway 10 from the first port 6 to the second port 8, via the through port 14 of the valve member 12.

(27) The fluid in the fluid passageway 10 may be under pressure and thus apply an outward force, illustrated by arrows 48, on the sleeve 18. When the pressure is sufficiently high, the outwards pressure 48 will cause the sleeve member 18 to deform, i.e. expand, into the cavity 21. With reference to FIGS. 4 and 5, this deformation may be facilitated by the corrugations 44 which allow the sleeve member 18 to expand. Deformation of the sleeve 18 is intended to refer to a change in shape of the sleeve 18 which results in a change of the shape of the cavity 21 which contains the medium 20.

(28) As the sleeve 18 deforms, the shape of the cavity 21 changes and the medium 20 forces the valve member 16 against the outer surface 34 of the valve member 20 to accommodate the expansion of the sleeve 18. In other words, the medium 20 transfers the outward force provided by the deformed sleeve 18 into a force acting on the sealing member 16. The fixed wall 23 provides a fixed reference point and so as the sleeve 18 expands the sealing member 16 will be pressed with more force against the valve member 12. This force may cause the sealing member 16 to move, at least by a small amount, towards the valve member 12. In addition, or alternatively, the force may cause the sealing member 16 to be compressed slightly and the sealing member 16 may not noticeably move within the cavity 21. The increased force provided by the medium 20 acting on the sealing member 16, in addition to the resilient bias provided by the resilient member 22, will therefore increase the integrity of the seal. Accordingly, the fluid pressure within the valve assembly 2 is actively used to increase the quality of the seal provided by the sealing member 16 so as to ensure that fluid cannot escape around the valve member 12.

(29) The stiffening band 38 serves to prevent the lower portion 36 of the sleeve 8 from deforming. This helps to prevent the lower portion 36 of the sleeve, which is adjacent to the sealing member 16, from acting on the sealing member 16 in a direction which does not act to improve the sealing provided by the sealing member 16. Accordingly, the stiffening band 38 helps to ensure the integrity of the seal provided by the sealing member 16.

(30) The second sealing arrangement 15B will function in an identical manner to that described above for the sealing arrangement 15A. Accordingly, the pressure of the fluid passing through the valve assembly 2 may be utilised to active improve the quality of the seal around the valve member 12 between the valve member 12 and each of the first and second ports 6, 8.

(31) With reference to FIG. 6, when the valve member 12 is in the closed position, and taking the first port 6 as in the inlet port, fluid may still be within valve assembly 2 in the portion of the fluid passageway 10 between the first port 6 and the valve member 12. The fluid pressure applied to the sleeve 18 by the fluid in the fluid passageway 10 will cause the sealing member 16 to be pressed against the valve member 12 with an increased force in the same manner as described above. Accordingly, the sealing arrangements 15A, 15B will serve to prevent the leaking of fluid around the valve member 12 when the valve member 12 is in the closed position as well as when it is in the open position.

(32) The valve member 12 may be moved between the open and closed positions described above using any suitable means. For example, a handle may be connected to the valve member 12. In another example, the valve member 12 may be driven between the open and closed positions by a motor.

(33) FIG. 7 shows a sectional view of a valve assembly 102 in accordance with another example of the present disclosure. The valve assembly 102 comprises a valve body 104 comprising a first port 106, a second port 108 and a further port in the form of a third port 150. The first port 106 and second port 108 are arranged in line with one another, and the third port 150 is orthogonal to both the first and second ports 106, 108. A valve member 112 is provided at an intersection of the fluid passageway 110 extending from each port 106, 108, 150. The valve member 112 comprises a right-angled through port 114. The valve member 112 may be a ball valve member.

(34) The valve member 112 may be rotated between a first open position in which the first port 106 and third port 150 are connected, a second open position in which the second port 108 and third port 150 are connected, and a closed position in which none of the ports 106, 108, 150 are connected. A first sealing arrangement 115A is arranged between the first port 106 and valve member 112, a second sealing arrangement 115B is arranged between the second port 108 and valve member 112, and a third sealing arrangement 115C is arranged between the third port 150 and the valve member 112. Each of the sealing arrangements 115A, 115B, 115C, may function in an identical manner to the sealing arrangement 15A described above with respect to FIGS. 1-6.

(35) In a similar manner to the first example described above, the sealing arrangements 115A, 115B, 115C act to prevent the unwanted leakage of fluid around the valve member 112 during use of the valve assembly 112. Without the presence of the sealing arrangements 115A, 115B, 115C, fluid may more easily leak around the valve member 112 and escape the valve assembly 102 out through a port 106, 108, 150, which is not connected by the valve member 112. Depending on the particular application of the valve assembly 102, such leakage could be dangerous and thus the sealing arrangements 115A, 115B, 115C help to reduce this risk.

(36) FIG. 8 shows a sectional view of a valve assembly 202 in accordance with a further example of the present disclosure. The valve assembly 202 comprises a valve body 204 which comprises four ports: a first port 106, a second port 208, a third port 250 and a fourth port 252. A valve member 212 is arranged at the intersection of the fluid passageway 210 extending between each of the ports 206, 208, 250, 252. The valve member 212 comprises a straight, through port 214 and therefore the valve member 212 can be positioned, e.g. through rotation, to connect two opposite ports 206, 208, 250, 252. As with the previous examples, the valve member 212 may be a ball valve member.

(37) A first sealing arrangement 215A is arranged between the first port 206 and valve member 212. A second sealing arrangement 215B is arranged between the second port 208 and valve member 212. A third sealing arrangement 215C is arranged between the third port 250 and the valve member 212. A fourth sealing arrangement 215D is arranged between the fourth port 252 and the valve member 212. The first, second, third and fourth sealing arrangements 215A, 215B, 215C, 215D may all be identical to the sealing arrangement 15A shown in FIG. 1 and may function in an identical manner. The sealing arrangements 215A, 215B, 215C, 215D may each act to prevent the leakage of fluid around the valve member 212 which may result in fluid leaking out through a port 206, 208, 250, 252 which is not connected for fluid flow.

(38) FIG. 9 shows a sectional view of a valve assembly 302 in accordance with a further example the present disclosure. The valve assembly 302 is identical to the valve assembly 2 shown in FIG. 1, except that each of the sealing arrangements 315A, 315B does not include a resilient member which biases the sealing member 316. Instead, the sealing arrangement 315A relies upon a force applied by the medium 320 to the sealing member 316 to achieve a suitable seal around the valve member 312. The medium 320 may be inserted into the cavity 321 under pressure such that even when there is minimal, or no, pressure applied to the sleeve 318 from fluid within the sleeve 318, the sealing member 316 may nonetheless be held against the valve member 316 under the pressure exerted by the medium 320. It may, therefore, be possible to avoid the need for a resilient member. This may reduce the cost of the valve assembly 302 and simplify its manufacture. The pressure which the medium 320 is inserted into the cavity 321 may depend on the application of the valve assembly 302, for example it may depend on the type of fluid which passes through the valve assembly 302. The pressure may also depend on the expected pressures of fluid in the valve assembly 2 in use.

(39) The sealing arrangements 315A, 315B illustrated in FIG. 9 function in an identical manner to the sealing arrangements 15A, 15B described above with respect to FIGS. 1-6, except that there is no resilient member which applies an additional biasing force to the sealing member 316. As the sleeve 318 is deformed, this forces the medium 320 against the sealing member 316 to further improve the quality of the seal provided.

(40) The second, i.e. further, sealing arrangement 315B arranged between the second port 308 and the valve member 312 may be identical to the first valve arrangement, as is depicted. Alternatively, however, the second sealing arrangement may have the same arrangement as the sealing arrangement 15A shown in FIG. 1. In other words, one of the sealing arrangements may comprise a resilient member, and one of them may not. This may depend on the particular configuration of the valve assembly 302 and, for example, which of the first and second ports 306, 308 is acting as the inlet port and which is acting as the outlet port.

(41) It will be appreciated by those skilled in the art that examples of the present disclosure provide an improved valve assembly. While specific examples of the disclosure have been described in detail, it will be appreciated by those skilled in the art that the examples described in detail are not limiting on the scope of the disclosure.