GB2203818A - Improvements in or relating to valves - Google Patents

Abstract

In a valve having a passage (8) including a tapered part (9a) and containing a valve member which includes a closure portion (10) rotatable about a transverse axis (12) between first and second positions and wherein an operating means provided to actuate the valve is moveable between a first position in which the valve is open and a second position in which the valve is closed, movement of the operating means from its first to its second position causes the closure portion (10) to rotate from its first to its second position and also to move the transverse axis (12) along the axis of package (8) to urge the portion (10) into sealing engagement with the tapered part (9a). Preferably an operating shaft (11) rotatable about axis (12) is eccentrically mounted in a bearing (13) having an axis (15) and is driven by a mechanism including a cam assembly (18 Fig 2) and locking rollers (71 Figs. 5, 6) are provided for locking the closure portion (10) in its closed position. <IMAGE>

Description

IMPROVEMENTS IN OR RELATING TO VALVES This invention relates to valves and more particularly, but not exclusively, is concerned with valves for high pressure applications.

Valves are known which comprise a chamber including a tubular portion and a valve member which includes a closure portion and which is located in the chamber so that it can be rotated about an axis extending transversely of the longitudinal axis of the tubular portion between a closed position in which the closure portion bridges across the tubular portion to prevent fluid flow through the tubular portion and an open position in which the closure portion lies adjacent an internal side wall of the tubular portion to allow fluid flow through the tubular portion.

A valve of this type is disclosed in U.S.

Patent Specification No.2 827 259. However, this valve is for use in air ducts operating at substantially atmospheric pressure in dust collection systems. The seal between the closure portion and the inner walls of the tubular portion when the closure portion is in its closed position is not particularly good nor does it need to be for the application for which it was designed. It is quite unsuitable for use in high pressure applications for conveying fluids such as liquids and suspensions under pressure.

It is an object of the present invention to provide a valve which is suitable for such applications.

It is a further object of the present invention to provide a valve for such high pressure applications which can be fully opened and fully closed by means of a single movement of an operating lever.

According to the present invention there is provided a valve for insertion between first and second pipe sections for controlling the flow of fluid between the pipe sections, which valve comprises: (i) a chamber having first and second openings for connection to said pipe sections and including a cylindrical wall defining a tubular portion between said first and second openings wherein said cylindrical wall includes a conical portion whereby a part of said tubular portion is tapered, (ii) a valve member which includes a closure portion and which is located in the chamber, said closure portion being mounted for rotation about an axis extending transversely of the longitudinal axis of said tubular portion between a first position in which the closure portion lies adjacent an inner surface of the cylindrical wall of the tubular portion to allow fluid flow through the tubular portion and a second position in which the closure portion bridges across the tubular portion, and (iii) operating means for actuating the valve member and movable between a first position in which the valve is open and a second position in which the valve is closed, movement of said means from said first to said second position causing the closure portion to rotate from its first to its second position and also to move the transversely extending axis along the longitudinal axis so as to urge the closure portion, when in its second position, into sealing engagement with the inner surface of the conical portion of the cylindrical wall to prevent fluid flow through the tubular portion.

In a particularly preferred embodiment said transversely extending axis is eccentrically mounted in bearings provided in the cylindrical wall. In this case, movement of the operating means actuates first and second drive mechanisms, the first drive mechanism serving to rotate the closure portion about said transversely extending axis and the second drive mechanism serving to rotate the bearings and thereby cause said transversely extending axis to be displaced along the longitudinal axis as a consequence of the eccentricity in the bearings.Thus, during a first part of its movement from the open first position to the closed second position, the operating means actuates the first drive mechanism so that the closure portion rotates about the transversely extending axis and moves from its first position to its second position and during a second part of its movement from the open first position to the closed second position the operating means actuates the second drive mechanism so that said transversely extending axis moves longitudinally with respect to the tubular portion to urge the periphery of the closure portion into sealing engagement with the inner surface of the conical part of the cylindrical wall of the tubular portion to close off the tubular portion to fluid flow.

For a better understanding of the invention and to show how the same may be carried into effect, reference will now be made, by way of example, to the accompanying drawings in which: Figure 1 is a vertical section through a valve in accordance with the present invention, Figure 2 is a vertical section through one side of the valve of Figure 1 in a plane perpendicular to the plane of the section shown in Figure 1, Figures 3a and 3b are plan and side views respectively of a first part of the valve shown in Figure 2, Figure 4 is a plan view of a second part of the valve shown in Figure 2, Figure 5 is a plan view of third and fourth parts of the valve shown in Figure 2, and Figure 6 is a plan view of a fifth part of the valve shown in Figure 2.

Referring now to Figure 1, the valve comprises a valve body formed from body halves 1 and 2 secured together by threaded studs 3 passing through cooperating flanges to define a chamber having a first opening 4 for connection to a first pipe section by means of flange 5 and a second opening 6 for connection to a second pipe section by means of flange 7. The chamber includes a generally tubular portion 8 defined by a cylindrical wall 9 comprising a conical portion 9a so that a part of the tubular portion in half 2 is tapered.

Provided in the chamber is a valve member comprising a closure portion 10 in the form of a visor mounted on a shaft 11 for rotation about axis 12 extending transversely across the tubular portion of the valve. The closure portion is circular in plan and has the shape obtained by projecting a circle onto the cylindrical surface of a cylinder.

The shaft 11 is eccentrically mounted in a bearing 13 mounted in a circular bore 14 provided in the cylindrical wall of the tubular portion so that the bearing 13 can rotate about its axis 15 extending transversely of the tubular section. An arm 16 is secured to the bearing 13 to facilitate rotating the bearing about its axis 15 and is fixed to a similar arm (not shown) secured by linking member 16a to a corresponding bearing (not shown) provided on the opposite side of the tubular portion 8.

Referring now to Figures 2 to 6, the valve comprises a cam assembly 18 mounted at one end of the shaft 11 for the visor 10. The cam assembly includes a first drive mechanism linking an operating means in the form of an input shaft 17 to the visor shaft 11 and a second drive mechanism linking the input shaft 17 to the bearings 13. The cam assembly comprises a casing 19 secured to the outer surfaces of the walls 9, 9a of the tubular portion by threaded studs 20. The input shaft 17 is mounted for rotation in the casing 19 coaxially with axis 12 and it terminates in a drive disc 21 carrying a central stub end 22.

The drive disc 21 is shown in Figures 3a and 3b and includes a radial slot 23 extending from the outer periphery towards the stub end 22 for accommodating a first drive roller 61 of a drive assembly comprising three rollers 61, 62 and 63 mounted on a pin 60.

The drive disc 21 is superposed on a disc 25 so that the stub end 22 projects into an elongated central slot 24 provided in the disc 25. Disc 25 constitutes a drive link for a purpose to be explained hereinafter and is shown in Figure 4. It includes a circular aperture 26 located between the end of the slot 24 and the outer periphery of the disc 25 and positioned on the longitudinal axis of the slot 24.

The pin 60 of the drive assembly passes through the aperture 26.

The disc 25 of the drive link is superposed on a pair of concentric discs shown in Figure 5. The pair of discs includes an inner disc 31 and an outer annular disc 32. The inner disc 31 includes a central square aperture 33 which fits over square sectioned end 34 of the visor drive shaft 11. It also includes, at its periphery, a first radially extending recess 35 for accommodating the second drive roller 62 of the drive assembly and a second radially extending recess 36 for accommodating a first locking roller 71 of a locking assembly comprising two locking rollers 71 and 73 mounted on a pin 72. The outer annular disc 32 includes at its inner periphery a first radially extending recess 37 to receive the second drive roller 62 and a second radially extending recess 38 to receive the first locking roller 71.The relative dispositions of the recesses 35 and 36 on the one hand and recesses 37 and 38 on the other are such that recesses 35 and 37 are opposite one another when recesses 36 and 38 are opposite one another. Also, the inner peripheral edge of the annular disc 32 is chamfered at portion 39 to provide a lead-in to the recess 37. The annular disc 32 also includes a circular aperture 40 for carrying a pin 41 (see Figure 2) which, at its other end, is secured to the arm 16.

The inner disc 31 and annular disc 32 are superposed, in the cam assembly 18, on a cam plate 50 shown in more detail in Figure 6. The cam plate 50 includes a central aperture 51 through which the visor shaft 11 passes. The plate also includes an arcuate slot 52 through which the pin 41 connecting the annular disc 32 with the arm 16 passes. The slot 52 is arcuate in shape so that it allows the pin 41 to follow an arcuate path when the annular disc 32 and the arm 16 exhibit rotary motion about axis 12.

The cam plate 50 also includes a radial slot 53 extending from the central aperture 51 towards the outer periphery of the plate 50. This slot 53 is for accommodating the second locking roller 73 of the locking assembly. Further, the cam plate 50 includes another slot generally denoted by reference numeral 57 and including a first generally arcuate portion 54, a second generally arcuate portion 55 located at a greater radial distance from the central aperture 51, and a generally tangential portion 56 linking the first and second arcuate portions 54 and 55. This slot is to accommodate the third drive roller 63 of the drive assembly.

In order to actuate the valve, the shaft 17 is caused to rotate about its longitudinal axis between a first angular position and a second angular position by means of a suitable operating lever (not shown).

In the case where the valve is open, the third drive roller 63 is in the arcuate portion 54 at the end of the slot 57, the second drive roller 62 is located in the recess 35 of the inner disc 31 and the first drive roller 61 is located at the closed inner end of the slot 23 in drive disc 21. As the shaft 17 commences to rotate from its first angular position in which the valve is open towards its second angular position in which the valve is closed, the drive assembly constituted by drive rollers 61,62 and 63 rotates with the drive disc 21 and, because the second drive roller 62 is located within the recess 35 of inner disc 31, inner disc 31 is caused to rotate.This causes the visor shaft 11 to rotate and move the visor 10 from a first position shown in Figure 1 wherein it lies adjacent to the inner surface of the cylindrical wall 9 of the tubular section 8 to a second position in which it bridges across the tubular portion 8. As the inner disc 31 is being rotated in this way, the third drive roller 63 is constrained to pass from the arcuate portion 52 to the tangential portion 56 of the slot 57 in the cam plate 50. This tangential movement of the drive assembly is accommodated by the slot 24 of the drive link 25 moving about the stub end 22. Meanwhile, the pin 60 of the drive assembly is positively located since it passes through the aperture 26 in the drive link and hence is supported by the drive link.Thus the drive assembly is caused to move radially along the recess 35 in the inner disc 31 until, by the time the third drive roller 63 has reached the second arcuate portion 55 of the slot 57 in the cam plate 50 the second drive roller 62 has left the recess 35 of inner disc 31 and entered into the recess 37 of the annular disc 32. During this movement the first drive roller 62 traverses towards the open end of the radial recess 23 in the drive disc 21. At this changeover position the inner disc 31 and the outer annular disc 32 have the relative dispositions shown in Figure 5.

Continued rotation of the shaft 17 is now transmitted to the annular disc 32 by the drive assembly with the third drive roller 63 being constrained to travel along the second arcuate portion 55 of the slot 57 in the cam plate 50. As the annular disc 32 rotates, the pin 41 linking it with the arm 16 follows a path from one end of the slot 52 in cam path 50 to the other. The rotational movement of the annular disc 32 is transmitted to the arms 16 by the pin 41 so as to rotate the bearings 13 in the bores 14.

This causes the visor 10 to move longitudinally with respect to the tubular portion 8 so that the outer periphery 61 of the visor 10 adopts the position shown in dotted lines in Figure 1 in which it is sealingly engaged against the inner surface of the conical portion 9a defining the tapered part of the tubular portion 8 so as to provide a fluid tight seal able to withstand high pressures.

When it is desired to open the valve, the shaft 17 is rotated from this closed second position to its original open first position and the abovedescribed sequence of events occurs in reverse.

Thus the first drive mechanism linking the input shaft 17 to the visor shaft 11 is constituted by the drive disc 21, the drive assembly and the inner disc 31 and the second drive mechanism linking the input shaft 17 to the bearings 13 is constituted by the drive disc 21, the drive assembly, the annular disc 32, the pin 41, and arms 16.

When the visor 10 is in its second position in which it bridges across the tubular portion, it is locked against further rotational movement by the locking assembly. Prior to the commencement of rotation of the shaft 17 from its first to its second position (and during the initial stages of such movement), the second locking roller 72 is at the closed end of the slot 53 in the cam plate 50 and the first locking roller 71 is in the recess 38 of the annular disc 32. Thus the annular disc 32 is prevented from rotating whilst the inner disc 31 is free to rotate. When the inner disc has reached the changeover position shown in Figure 5, the locking assembly can then be slid radially towards the rotational axis of the disc 31 so that the first locking roller 71 is located in the recess 36 of inner disc 31. The second locking roller 72 is still located in the slot 53 of cam plate 50 (but has moved nearer to the aperture 51) and thereby prevents the inner disc 31 from rotating whilst the annular disc 32 is rotating as a consequence of the drive shaft 17 rotating through the second stage of its movement to its closed position. Thus, the inner disc 31 is locked whilst the annular disc 32 rotates and hence the visor 10 is retained in its second position whilst it is moved longitudinally of the tubular portion during the second stage of rotational movement of the shaft 17.

It can be seen that a single rotational movement of the drive shaft 17 causes the closure portion firstly to move from its open first position to its bridging second position and then secondly to cause the closure portion to move axially into sealing engagement with the inner surface of the conical portion of the cylindrical wall of the tubular section.

Moreover, the closure portion is positively driven throughout the whole of its movement.

The valve is such that, when in the open position, there is negligible obstruction of the fluid flow yet, when in the closed position, a metal to metal seal is achieved which can be maintained under arduous conditions. The valve is particularly suitable for use in regulating the flow of liquids flowing under high pressures, such as suspensions containing abrasive particles.

Claims (6)

CLAIMS:

1. A valve for insertion between first and second pipe sections for controlling the flow of fluid between the pipe sections, which valve comprises: (i) a chamber having first and second openings for connection to said pipe sections and including a cylindrical wall defining a tubular portion between said first and second openings wherein said cylindrical wall includes a conical portion whereby a part of said tubular portion is tapered, (ii) a valve member which includes a closure portion and which is located in the chamber, said closure portion being mounted for rotation about an axis extending transversely of the longitudinal axis of said tubular portion between a first position in which the closure portion lies adjacent an inner surface of the cylindrical wall of the tubular portion to allow fluid flow through the tubular portion and a second position in which the closure portion bridges across the tubular portion, and (iii) operating means for actuating, the valve member and movable between a first position in which the valve is open and a second position in which the valve is closed, movement of said means from said first to said second position causing the closure portion to rotate from its first to its second position and also to move the transversely extending axis along the longitudinal axis so as to urge the closure portion, when in its second position, into sealing engagement with the inner surface of the conical portion of the cylindrical wall to prevent fluid flow through the tubular portion.

2. A valve as claimed in claim 1 wherein said transversely extending axis is eccentrically mounted in bearings provided in the cylindrical wall.

3. A valve as claimed in claim 2 which includes first and second drive mechanisms actuated by movement of the operating means, the first drive mechanism serving to rotate the closure portion about said transversely extending axis and the second drive mechanism serving to rotate the bearings and thereby cause said transversely extending axis to be displaced along the longitudinal axis as a consequence of the eccentricity in the bearings.

4. A valve as claimed in claim 3 which includes a cam assembly which comprises a cam plate, relatively rotatable concentric inner and outer discs superposed on the cam plate, a drive disc superposed on the concentric discs, and a drive assembly operably linking the discs and the cam plate for transmitting rotational movement from the drive disc to the inner and outer discs wherein the drive disc is rotatable by said operating means, said closure portion is rotatable about the transverse axis by rotation of said inner disc, and said closure portion is movable along said longitudinal axis by rotation of said outer disc whereby said first mechanism is constituted by the drive disc, the drive assembly and the inner disc and said second mechanism is constituted by the drive disc, the drive assembly and the outer disc.

5. A valve as claimed in claim 4 wherein a locking means is provided to prevent rotation of the inner disc during rotation of the outer disc.

6. A valve as claimed in claim 1 substantially as hereinbefore described with reference to and as illustrated in the accompanying drawings.