GB1591622A

GB1591622A - Fluid flow control valves

Info

Publication number: GB1591622A
Application number: GB3849776A
Authority: GB
Original assignee: CUSTOM VALVE CO Ltd
Current assignee: CUSTOM VALVE CO Ltd
Priority date: 1977-09-15
Filing date: 1977-09-15
Publication date: 1981-06-24

Description

(54) IMPROVEMENTS IN FLUID FLOW CONTROL VALVES (71) We, THE CUSTOM VALVE COM- PANY LIMITED, a British Company, of Rodborough Court, Stroud, Gloucestershire, do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement::- The invention relates to fluid flow control valves of the kind comprising a valve body, a chamber formed in the valve body, at least two ports formed in the valve body and opening into said chamber, a valve seat surrounding each port within the chamber, a rotatable valve member located within said chamber and engaging said valve seats, at least one passage extending through said valve member and between ports in the surface thereof, and means for rotating the valve member between an open position in which the ports in the valve member are in communication respectively with the ports in the valve body and a closed position in which said respective ports are not in communication.

In a control valve of this kind it is desirable that the valve member should closely engage the valve seats in at least one of said positions of the valve member, to ensure a good fluidtight seal. Whether such a good seal is required in the open or in the closed position of the valve member depends largely upon the use to which the control valve is being put.

This necessity for close engagement between the valve member and the valve seats can lead to difficulties in assembling the valve member within the chamber in the valve body. This is particularly true in the case of valves having separately formed valve seats which are slightly compressible. It is desirable in this case that the valve member and valve seats should be insertable as an assembly into the chamber of the valve body. To permit such insertion as an assembly, while ensuring at the same time that, when assembled, the valve member slightly compresses the valve seats, it has been proposed that the chamber within the valve body should be provided with accurately machined relatively inclined surfaces and that the assembly of valve member and valve seats should have a correspondingly tapered form.

However, these proposals have involved considerable expense and have not always been reliable in operation. It is accordingly an object of the invention to provide an improved fluid flow control valve of the kind first referred to wherein the valve may be assembled in a simple and economical manner, while at the same time ensuring that, when assembled, the required close engagement between the valve member and the valve seats is obtained.

According to the invention there is provided a fluid flow control valve comprising a valve body, a chamber formed in the valve body and having, at one side thereof an aperture covered by a removable cover which thereby provides one wall of the chamber, at least two ports formed in the valve body and opening into said chamber, a valve seat surrounding each port within the chamber, each valve seat comprising a member formed separately from said valve body and located within said chamber so as to surround its associated port, a rotatable valve member located within said chamber and engaging said valve seats and having a clearance between the outer surface of the valve member and the inner surface of said chamber, at least one passage extending through said valve member and between ports in the surface thereof and means for rotating the valve member between an open position in which the ports in the valve member are in communication respectively with the ports in the valve body and a closed position in which said respective ports are not in communication, the valve member having, in a plane perpendicular to the axis of rotation thereof, major and minor axes spaced angularly apart in said plane, the dimension of the valve member being slightly greater along said major axis, whereby engagement between the valve member and at least one of said valve seats is closer when the major axis is in line with said valve seat that it is when the minor axis is in line with that valve seat, the cross-section of the chamber in the valve body being such that the valve member together with the valve seats may be inserted into and removed from the chamber as a unit, through the aforesaid aperture at one end thereof, by movement of the valve member in the direction of the axis of rotation, with the minor axis of the valve member in line with the aforesaid valve seat.

Thus the valve member may readily be inserted in the chamber in the valve body by orientating it with its minor axis in line with said valve seat, and after assembly of the valve member within the chamber rotation of the valve member to bring its major axis in line with the valve seat will ensure close engagement between the valve member and the valve seat, slightly compressing the valve seat if it is of a resilient kind.

The particular disposition of the major and minor axes in relation to the ports in the valve member will depend on the use to which the valve is to be put. Thus where the valve is a cut-off valve where the best seal between the valve member and the valve seats is required in the closed position, the ports in the surface of the valve member are located at opposite ends of said minor axis.

In this case the minor axis of the valve member is preferably at right angles to the major axis thereof.

In the case where the ports in the valve member, connected by said passage, are not on opposite sides of the valve member, the valve member may have two major axes spaced angularly apart from one another and from the minor axis, the ports being each located at an end of a different one of said major axes. Thus when the valve member is in the open position the major axes will be in line with the valve seats respectively so that a good seal is obtained.

In the latter case there may be provided two further ports formed in the valve body and opening into said chamber, a further valve seat surrounding each further port within the chamber and a further passage extending through said valve member and between further ports in the surface thereof said further ports in the surface of the valve member being located respectively at the opposite ends of said major axes to the first said ports in the surface of the valve member.

In any of the above arrangements the valve member may be substantially partspherical in shape, said minor axis being defined by a portion thereof being of slightly reduced diameter. Alternatively the valve member may be substantially cylindrical in shape. the said minor axis again being defined by a portion thereof being of slightly reduced diameter.

As mentioned above, each valve seat may be formed separately from said valve body and may comprise a member, preferably annular, located within said chamber so as to surround its associated port. Each said valve seat is preferably formed from compressible resilient material and may comprise an annular sealing element of resilient plastics material surrounded by a metal carrier. Cage means may be provided within said chamber to locate the valve seats within the chamber.

In the above arrangements the chamber in the valve body may be of substantially constant cross-section, for example, it may be of substantially constant circular or rectangular cross-section.

The following is a more detailed description of various embodiments of the invention, reference being made to the accompanying drawings in which: Figure 1 is a vertical section through a control valve according to the invention; Figure 2 is a horizontal section through the control valve of Figure 1; Figure 3 is a vertical section through an alternative form of control valve; Figure 4 is a horizontal section through the control valve of Figure 3; Figure 5 is a vertical section through a further form of control valve; Figure 6 is a horizontal section through the control valve of Figure 5; Figure 7 is a horizontal section through the valve member of a still further form of control valve; and Figure 8 is a vertical section showing an alternative shape of valve member.

Referring to Figures 1 and 2: the fluid flow control valve comprises a valve body 10 in which is formed a rectangular chamber 11 of constant cross-section. Opposed circular ports 12 and 13 are formed in the valve body and open into the chamber 11. Each of the ports 12 and 13 is encircled by an annular valve seat 14 located within the chamber 11.

Each valve seat comprises an annular sealing element 15 formed from compressible resilient material, such as polytetrafluoroethylene, encircled by a cylindrical metal carrier 16. Each annular element 15 is formed with an annular, part-spherical sealing surface 17.

Located within the chamber 11 is a substantially spherical valve member 18, there being, as shown, a clearance between the outer surface of the valve member and the inner surface of the chamber. The valve member 18 is formed with a diametrically extending passage 19 which extends between circular ports 20 and 21 in the surface of the valve member. The upper part of the valve member 18 is formed with a slot 22 in which is received a lug 23 formed on the lower end of a vertical spindle 24 which is rotatably mounted in bearings in a cover 25. The cover 25 is secured to the top of the valve body 10 by screws 26 and forms an upper wall of the chamber 11. A valve operating lever 27 is connected to the threaded outer end of the spindle 24 by clamping nuts 28.

Referring now to Figure 2: although the valve member 18 is generally spherical in shape it is formed with a major axis 29 and a minor axis 30, its diameter along its major axis (which diameter is indicated at 31) being slightly greater than its effective diameter (indicated at 32) along its minor axis 30. It will be appreciated that, due to the presence of the passage 19, the sphere does not extend for its full diameter along its minor axis 30 and the dimension 32 indicates what the full diameter along this axis would be if the sphere were complete as indicated by broken lines.

The difference in dimension between the diameters 31 and 32 may be of the order of one per cent. For example, for a spherical valve member having a radius of 0.75 inches, the difference in dimension may be 0.015 inches.

To assemble the valve as shown in Figures 1 and 2, the valve seats 14 are first assembled on opposite sides of the valve member 18 with the minor axis 30 of the valve member in line with the valve seats. Due to the valve member being reduced in diameter along this axis, it is then possible for the assembly of valve member and valve seats to be inserted, as a unit, into the chamber 11 without difficulty and slid to the position shown in Figures 1 and 2. When the valve member and valve seats have been inserted in the chamber, the cover 25 is secured to the valve body by means of the screws 26, the lug 23 being located in the slot 22 in the upper side of the valve member. The valve is then in the open position.When the lever 27 is turned 90 to move the valve member 18 to the closed position, the surface of the valve member is pressed more closely against the valve seats due to the larger diameter of the valve member along its major axis. This serves to apply a degree of compression to the valve seats to obtain a fluid-tight sealing engagement between the valve member and the sealing surfaces 17 of the valve seats, and between the wall of the chamber 11 and the valve seats.

Figures 3 and 4 show an alternative form of control valve in which the valve member is generally cylindrical instead of being generally spherical in shape. In this arrangement the chamber 33 in the valve body 34 is cylindrical and the resilient valve seats 35 are part cylindrical. To prevent movement of the valve seats 35 around the walls of the chamber 33 there is provided a part-cylindrical metal cage 36 which is fitted within the chamber 33 but is clear of the surface of the cylindrical valve member 37.

The valve member 37 is formed with a central diametrically extending passage 38.

Other parts of the valve are generally similar to the valve shown in Figures 1 and 2 and need not therefore be described in further detail.

As in the previous arrangement, the valve member 37 has a major axis 39 and a minor axis 40, the diameter of the valve member being slightly greater along major axis than it is along its minor axis. Thus the valve member and valve seats may be inserted into the valve chamber 33 by first assembling them together as a unit, with the valve seats in line with the minor axis of the valve member, and then sliding the assembled unit into the valve chamber. After insertion of the unit in the chamber, rotation of the valve member through 90 to the closed position will bring the major axis of the valve member into line with the valve seats, thus compressing the valve seats to obtain a fluid-tight seal.

Figures 5 and 6 show a two-way control valve in which a generally spherical valve member 41 is formed with two passages 42 and 43 extending between ports in the surface of the valve member. In this arrangement the valve body 44 is formed with four ports 45, 46, 47 and 48, opening into the valve chamber which, as best seen in Figure 5, comprises a cylindrical portion 69 and bottom, part-spherical portion 70. The ports 45, 46, 47 and 48 are surrounded, where they open into the valve chamber, by resilient valve seats 49, 50, 51 and 52 respectively.

Each valve seat comprises a cylindrical metal carrier encircling a resilient sealing element formed with a part spherical annular sealing surface which engages the outer surface of the valve member 41. The valve seats are located within the cylindrical portion 69 of the valve chamber by a metal cage 53.

In the position of the valve member 41 shown in Figure 6, the passage 42 places the ports 45 and 46 into communication, and the passage 43 places the ports 47 and 48 into communication. The valve member 41 is rotatable through 90 to a second position in which the passage 42 places the ports 46 and 47 into communication and the passage 43 places the ports 45 and 48 into communication. It will be appreciated that it is desirable for there to be a good fluid-tight seal between the valve member and the valve seat in both of these two positions of the valve member.

Consequently, in this case, the valve member 41 has two major axes 54 and 55 arranged at right angles, and two minor axes 56 and 57, also arranged at right angles to one another, and at 45" to the major axes. In assembling the valve, the four valve seats are first assembled on the valve member 41 with the four valve seats being in line with the two minor axes 56 and 57. The assembly of valve member and valve seats is then small enough to be slid, as a unit, into the cylindrical portion 69 of the valve chamber, the valve seats being brought to the positions where they encircle their respective ports in the valve body 44.When the valve member is subsequently rotated through 456 to bring the passages 42 and 43 into communication with respective pairs of ports in the valve body, one of which positions is shown in Figure 6, the major axes of the valve member are brought into line with the valve seats, thus applying compression to the valve seats and forming good fluid-tight seals.

The arrangement for rotating the valve member in Figures 5 and 6 is similar to that previously described and will not therefore be described in further detail.

Figure 7 shows a horizontal section through an alternative form of spherical or cylindrical valve member 58 which is formed with a single T-shaped passage 59 communicating with three ports in the surface of the valve member. In this case also there is required good fluid-tight sealing between the valve member and the valve seats when the passage 59 in the valve member is placing various ports in the valve body into communication. Consequently the valve member 58 is again formed with two major axes 60 and 61 arranged at right angles to one another and passing through the ports in the surface of the valve member, and with two minor axes, which are also arranged at 90 to one another and at 45 to the major axes.

In the above described arrangements the valve members have either been generally spherical or cylindrical in shape. However, alternative forms of valve member may be employed and one such is shown in vertical section in Figure 8. The valve member 64 shown in Figure 8 is in the form of a thick circular disc having peripheral valve seatengaging surfaces 65 which may be tapered or part-spherical as shown. The upper and lower surfaces of the valve member 64 are flat, and the upper surface is formed with upwardly projecting lugs 66 defining between them a slot 67 for engagement by the means for rotating the valve member.

In each of the above-described arrangements, the valve member is of solid construction with internal passages formed therein. In the case of such valve members, the required major and minor axes may be provided by first forming an exactly spherical or cylindrical valve member and then reducing the diameter of the valve member at the ends of the desired minor axis or axes by a machining or grinding operation. Alternatively the valve member may be provided by first forming a hollow spherical or cylindrical member in which ports are formed, so that the hollow interior of the member constitutes the passage connecting said ports. The hollow member is then compressed to a predetermined extent along a diameter thereof corresponding to the required minor axis.

The member is compressed to an extent greater than the required reduction in diameter so that when the compression is released the member will relax by a forecastable amount to provide the required reduction in diameter. Alternatively, the valve member may be specially cast or machined initially to provide the major and minor axes.

It will be appreciated that in certain of the above described arrangements the chamber within which the valve member is rotatable may, at times, fill with the fluid being controlled by the valve. It is accordingly necessary that the cover for the valve chamber is in fluid-tight engagement with the valve body and, in the above described arrangements it will be noted that a resilient sealing ring is provided between the cover and the valve body, and that resilient seals are also provided between the spindle for rotating the valve member and its bearing in the cover.

The extent of reduction in diameter of the valve member required to provide each minor axis may be varied depending on the degree of ease of assembly required, and the degree of compression of the valve seat required in the assembled valve. However, although the reduction in diameter should be sufficient to permit ease of assembly, there should still be sufficiently close engagement between the valve member and the valve seats, in all positions, to avoid any significant play.

WHAT WE CLAIM IS: 1. A fluid control valve comprising a valve body, a chamber formed in the valve body and having, at one side thereof, an aperture covered by a removable cover which thereby provides one wall of the chamber, at least two ports formed in the valve body and opening into said chamber, a valve seat surrounding each port within the chamber, each valve seat comprising a member formed separately from said valve body and located within said chamber so as to surround its associated port, a rotatable valve member located within said chamber and engaging said valve seats and having a clearance between the outer surface of the valve member and the inner surface of said chamber, at least one passage extending through said valve member and between ports in the surface thereof, and means for rotating the valve member between an open position in which the ports in the valve member are in communication respectively with the ports in the valve body and a closed position in which said respective ports are not in communication, the valve member having, in a plane perpendicular to the axis of rotation thereof, major and minor axes spaced angularly apart in said plane, the dimension of the valve member being slightly greater along said major axis,

**WARNING** end of DESC field may overlap start of CLMS **.

Claims

**WARNING** start of CLMS field may overlap end of DESC **. they encircle their respective ports in the valve body 44. When the valve member is subsequently rotated through 456 to bring the passages 42 and 43 into communication with respective pairs of ports in the valve body, one of which positions is shown in Figure 6, the major axes of the valve member are brought into line with the valve seats, thus applying compression to the valve seats and forming good fluid-tight seals. The arrangement for rotating the valve member in Figures 5 and 6 is similar to that previously described and will not therefore be described in further detail. Figure 7 shows a horizontal section through an alternative form of spherical or cylindrical valve member 58 which is formed with a single T-shaped passage 59 communicating with three ports in the surface of the valve member. In this case also there is required good fluid-tight sealing between the valve member and the valve seats when the passage 59 in the valve member is placing various ports in the valve body into communication. Consequently the valve member 58 is again formed with two major axes 60 and 61 arranged at right angles to one another and passing through the ports in the surface of the valve member, and with two minor axes, which are also arranged at 90 to one another and at 45 to the major axes. In the above described arrangements the valve members have either been generally spherical or cylindrical in shape. However, alternative forms of valve member may be employed and one such is shown in vertical section in Figure 8. The valve member 64 shown in Figure 8 is in the form of a thick circular disc having peripheral valve seatengaging surfaces 65 which may be tapered or part-spherical as shown. The upper and lower surfaces of the valve member 64 are flat, and the upper surface is formed with upwardly projecting lugs 66 defining between them a slot 67 for engagement by the means for rotating the valve member. In each of the above-described arrangements, the valve member is of solid construction with internal passages formed therein. In the case of such valve members, the required major and minor axes may be provided by first forming an exactly spherical or cylindrical valve member and then reducing the diameter of the valve member at the ends of the desired minor axis or axes by a machining or grinding operation. Alternatively the valve member may be provided by first forming a hollow spherical or cylindrical member in which ports are formed, so that the hollow interior of the member constitutes the passage connecting said ports. The hollow member is then compressed to a predetermined extent along a diameter thereof corresponding to the required minor axis. The member is compressed to an extent greater than the required reduction in diameter so that when the compression is released the member will relax by a forecastable amount to provide the required reduction in diameter. Alternatively, the valve member may be specially cast or machined initially to provide the major and minor axes. It will be appreciated that in certain of the above described arrangements the chamber within which the valve member is rotatable may, at times, fill with the fluid being controlled by the valve. It is accordingly necessary that the cover for the valve chamber is in fluid-tight engagement with the valve body and, in the above described arrangements it will be noted that a resilient sealing ring is provided between the cover and the valve body, and that resilient seals are also provided between the spindle for rotating the valve member and its bearing in the cover. The extent of reduction in diameter of the valve member required to provide each minor axis may be varied depending on the degree of ease of assembly required, and the degree of compression of the valve seat required in the assembled valve. However, although the reduction in diameter should be sufficient to permit ease of assembly, there should still be sufficiently close engagement between the valve member and the valve seats, in all positions, to avoid any significant play. WHAT WE CLAIM IS:

1. A fluid control valve comprising a valve body, a chamber formed in the valve body and having, at one side thereof, an aperture covered by a removable cover which thereby provides one wall of the chamber, at least two ports formed in the valve body and opening into said chamber, a valve seat surrounding each port within the chamber, each valve seat comprising a member formed separately from said valve body and located within said chamber so as to surround its associated port, a rotatable valve member located within said chamber and engaging said valve seats and having a clearance between the outer surface of the valve member and the inner surface of said chamber, at least one passage extending through said valve member and between ports in the surface thereof, and means for rotating the valve member between an open position in which the ports in the valve member are in communication respectively with the ports in the valve body and a closed position in which said respective ports are not in communication, the valve member having, in a plane perpendicular to the axis of rotation thereof, major and minor axes spaced angularly apart in said plane, the dimension of the valve member being slightly greater along said major axis,

whereby engagement between the valve member and at least one of said valve seats is closer when the major axis is in line with said valve seat than it is when the minor axis is in line with that valve seat, the cross-section of the chamber in the valve body being such that the valve member together with the valve seats may be inserted into and removed from the chamber as a unit, through the aforesaid aperture at one end thereof by movement of the valve member in the direction of the axis of rotation, with the minor axis of the valve member in line with the aforesaid valve seat.

2. A control valve according to claim 1 wherein the ports in the surface of the valve member are located at opposite ends of said minor axis.

3. A control valve according to claim 2 wherein the minor axis of the valve member is at right angles to the major axis thereof.

4. A control valve according to claim 1 wherein the valve member has two major axes spaced angularly apart from one another and from said minor axis.

5. A control valve according to claim 4 wherein said ports in the surface of the valve member are each located at an end of a different one of said major axes.

6. A control valve according to claim 5 comprising two further ports formed in the vavle body and opening into said chamber, a further valve seat surrounding each further port within the chamber, and a further passage extending through said valve member and between further ports in the surface thereof said further ports in the surface of the valve member being located respectively at the opposite ends of said major axes to the first said ports in the surface of the valve member.

7. A control valve according to any of claims 4 to 6 wherein said two major axes are at right angles to one another.

8. A control valve according to claim 7 wherein the mimor axis of the valve member is at 45 to the major axes.

9. A control valve according to claim 8 wherein the valve member has two minor axes spaced angularly apart at right angles to one another.

10. A control valve according to claim 4 wherein said passage in the valve member has an extension leading to an additional port in the surface of the valve member which port, in the open position of the valve member, communicates with an additional port formed in the valve body and surrounded by a valve seat within the chamber, and wherein the first said ports in the surface of the valve member are located at opposite ends of one of said major axes, and the additional port in the surface of the valve member is located at one end of the other of said major axes.

11. A control valve according to any of the preceding claims wherein said valve member is substantially part-spherical in shape, said minor axis being defined by a portion thereof being of slightly reduced diameter.

12. A control valve according to any of the preceding claims wherein said valve member is substantially cylindrical in shape, said minor axis being defined by a portion thereof being of slightly reduced diameter.

13. A control valve according to any of the preceding claims wherein each said valve seat is formed from compressible resilient material.

14. A control valve according to claim 13, wherein said valve seat comprises an annular sealing element of resilient plastics material surrounded by a metal carrier.

15. A control valve according to any of the preceding claims wherein cage means are provided within said chamber to locate the valve seats within the chamber.

16. A control valve according to any of the preceding claims wherein said chamber is of substantially constant cross-section as it extends from said cover, the central axis of the chamber coinciding with the axis of rotation of the valve member.

17. A control valve according to claim 16 wherein said chamber is circular in crosssection.

18. A control valve according to claim 17, wherein said chamber is rectangular in cross-section.

19. A method of forming a valve member for use in the control valve according to claim 11 comprising forming a hollow partspherical member with said ports, and compressing the member to a predetermined extent along a diameter thereof corresponding to said minor axis, said predetermined extent being greater than the required reduction in diameter by an amount such that the member, when the compression is released, relaxes to an extent to give said required reduction in diameter.

20. A method of forming a valve member for use in the control valve according to claim 12 comprising forming a hollow cylindrical member with said ports, and compressing the member to a predetermined extent along a diameter thereof corresponding to said minor axis, said predetermined extent being greater than the required reduction in diameter by an amount such that the member, when the compression is released, relaxes to an extent to give said required reduction in diameter.

21. A fluid flow control valve substantially as hereinbefore described with reference to Figures I and 2, Figures 3 and 4, Figures 5 and 6, or Figures 5 and 6 as modified according to Figure 7 or Figure 8 of the accompanying drawings.