Field of the invention

[0001] The invention relates to a pinch valve and in a particular to a pinch valve assembly for a pipe. The invention has been developed primarily for use as a pinch valve assembly for a flexible valve sleeve and will be described hereinafter by reference to this application.

Background of the invention

[0002] The following discussion of the prior art is intended to present the invention in an appropriate technical context and allow its advantages to be properly appreciated. Unless clearly indicated to the contrary, however, reference to any prior art in this specification should not be construed as an express or implied admission that such art is widely known or forms part of common general knowledge in the field.

[0003] A pinch valve with an independent support for the actuator and mechanical pinch mechanism has been widely applied in industry. This pinch valve has a flexible valve sleeve that can be removed without removing the actuator and independent support. The pinch valve in one variant comprises a tubular concentric two-part valve body that is longitudinally split along its length to partly enclose the valve sleeve so as to provide a barrier to the leakage of pressurised and/or hazardous fluids in the event of a valve sleeve failure.

[0004] However, one problem with this variant is that when supported on both ends by flanged supports there are difficulties of access and structural weight. Whilst the valve sleeve is still removable, much of the advantage gained by the simple sleeve replacement procedure is lost due to the time and effort involved with unbolting and re-fixing the concentric two-part valve body and the supports. The flanges of the valve sleeve are located between mating flanges of the valve body and the flanges of the piping connected to the valve sleeve. This is done so that the valve sleeve flanges are used as a gasket to fluidly seal the piping and valve body. This arrangement thus creates additional steps in the sleeve removal and replacement process that results in a more labour and wasted time.

[0005] Also, jacking bolts are used to maintain the connection between the piping and the upper half of the valve body. This imposes additional installation costs and time. [0006] In addition, the valve body has opposed circumferential slots cut into each valve body half to allow the pinch bars from the mechanical pinching mechanism to compress or deform the flexible valve sleeve in operation. This arrangement results in additional manufacturing to either cast the valve body halves with the slots or fabricate the valve body in sections to achieve the desired slots.

[0007] It is an object of the present invention to overcome or ameliorate at least one of the disadvantages of the prior art, or to provide a useful alternative.

Summary of the invention

[0008] According to a first aspect of the invention, there is provided a pinch valve assembly comprising:

a flexible sleeve adapted for attachment to at least one conduit in communication with a source of fluid;

a mechanical pinching mechanism for pinching the flexible sleeve and thereby reducing the effective cross-sectional flow area thereof; and

a valve housing substantially enclosing said flexible sleeve, said valve housing comprising a mounting section for connecting said valve housing to one end of said at least one conduit;

wherein said valve housing comprises at least one removable portion to permit access to the interior of said valve housing and said flexible sleeve, without removal or loosening of the connection between said mounting section and said at least one conduit end.

[0009] Unless the context clearly requires otherwise, throughout the description and the claims, the words "comprise", "comprising", and the like are to be construed in an inclusive sense as opposed to an exclusive or exhaustive sense; that is to say, in the sense of "including, but not limited to".

[0010] Furthermore, as used herein and unless otherwise specified, the use of the ordinal adjectives "first", "second", "third", etc., to describe a common object, merely indicate that different instances of like objects are being referred to, and are not intended to imply that the objects so described must be in a given sequence, either temporally, spatially, in ranking, or in any other manner. [001 1] Preferably, said valve housing encloses said mechanical pinching mechanism.

[0012] Preferably, said at least one removable portion comprises a lower housing section of said valve housing. Alternatively or additionally, said at least one removable portion comprises an upper housing section. In one preferred form, said at least one removable portion comprises two upper housing sections. In one particularly preferred form, said two upper housing sections are removably attached at opposite sides of said mounting section.

[0013] In yet another alternative or addition, said at least one removable portion comprises one or more side panels or sections.

[0014] Preferably, the assembly comprises an actuator for selectively operating on said mechanical pinching mechanism to regulate fluid flow through said flexible sleeve. More preferably, said mounting section supports said actuator. Hence, the interior of said valve housing and said flexible sleeve is accessible without further removing or loosening of the support of said actuator by said mounting section. In some embodiments, said mounting section is connected to said actuator. In other embodiments, said at least one removable section is located opposite to a portion of said mounting section that is connected to said actuator. Thus, in these embodiments, the interior of said valve housing and said flexible sleeve is accessible without further removing or loosening of the connection between said mounting section and said actuator.

[0015] Preferably, said mounting section comprises an exterior mounting face for connecting said at least one conduit end. More preferably, said exterior mounting face is located on an exterior surface of one end of said mounting section.

[0016] Preferably, said mounting section comprises an interior mounting face for connecting said flexible sleeve. More preferably, said interior mounting face is located on an interior surface of said mounting section. In one preferred form, said interior mounting face is adjacent to said exterior mounting face.

[0017] Preferably, said at least one conduit comprises two conduits and said mounting section comprises two of said exterior mounting faces for connecting respective ends of said conduits. More preferably, said mounting faces are located on exterior surfaces of opposed ends of said mounting section. Brief description of the drawings

[0018] A preferred embodiment of the invention will now be described, by way of example only, with reference to the accompanying drawings in which:

[0019] Figure 1 is an exploded view of a pinch valve assembly in accordance with one embodiment of the invention;

[0020] Figure 2 is an underneath perspective view of the pinch valve assembly of Figure 1 , and

[0021] Figure 3 is a top perspective view of the pinch valve assembly of Figure 1 . Preferred embodiments of the invention

[0022] The present invention will now be described with reference to the following example which should be considered in all respects as illustrative and non-restrictive. Referring to Figure 1 , a pinch valve 1 assembly in accordance with a preferred embodiment of the invention comprises a flexible sleeve 2 adapted for attachment to at least one conduit (in the form of two pipes 3, as best shown in Figure 3) in communication with a source of fluid and a mechanical pinching mechanism 4 for pinching the flexible sleeve and thereby reduce the effective cross-sectional flow area of the sleeve. The flexible sleeve 2 is in the form of a valve sleeve and the mechanical pinching mechanism comprises opposed pinch bars 4a, 4b that mechanically pinch the valve sleeve to regulate fluid flow therein and hence the pipe 3.

[0023] The assembly 1 also comprises an actuator 5 for selectively operating on the mechanical pinching mechanism 4 to regulate fluid flow through the flexible sleeve 2, and a valve housing 6 having a mounting section 7 for connecting to one end of each pipe 3. The valve housing 6 substantially encloses the flexible sleeve 2 and the mechanical pinching mechanism 4.

[0024] The mounting section 7 is in the form of a mounting frame that has openings 10 at opposite ends to fluidly connect the pipes 3 to the valve sleeve 2. Through bores 1 1 are provided around the openings 10 so as to connect the sleeve attachment mechanism in the form of flanges 12 on either end of the valve sleeve 2, as well as corresponding flanges (not shown) on the pipe 3, to the mounting frame 7 on opposite sides. That is, the valve sleeve flanges 12 are connected to the mounting frame 7 at inside or interior mounting faces 13, while the pipe flanges are connected to the mounting frame 7 at outside or exterior mounting faces 14, preferably by countersunk screws (not shown). This allows the faces of each sleeve flange 12 to be mounted directly adjacent to each interior mounting face 13 at either end. Bolts 15 and nuts 16 are generally used to connect the valve sleeve 2 to the mounting frame 7. However, other suitable types of fasteners may be used. Thus, the valve housing also substantially encloses the flexible sleeve flanges 12.

[0025] The actuator 5 is in the form of a pneumatic or hydraulic piston assembly that is mounted to the mounting frame 7 via a support plate 18 that is fixedly connected to posts 19 on the mounting frame. Other suitable actuators include a handwheel, geared handwheel, electrically driven actuator and the like. The mounting section 7 thus supports the actuator 5 via this fixed connection of the support plate 18 to the posts 19. As a result, the mounting frame 7 is either rigidly or fixedly connected to the pipes 3 and the piston assembly 5 at the same time.

[0026] The valve housing 6 is a multi-part structure comprising the mounting frame 7 and several removable portions in the form of a lower housing section 20 and two upper housing sections 21 and 22. The removable lower housing section 20 and upper housing sections 21 , 22 permit access to the interior of the valve housing 6 and to the valve sleeve 2 without removal or loosening of the connection between mounting frame 7 and the conduit flanges. In addition, the interior of the valve housing 6 is also accessible via the removable lower and upper housing sections 20, 21 , 22 without disturbing the connection of the actuator piston assembly 5 to the mounting frame 7. The lower housing section 20 and upper housing sections 21 , 22 slidably engage the mounting frame 7 and can be removably connected in a number of ways. For example, the housing sections can be connected by using fasteners, such as bolts or screws. It will be appreciated by one skilled in the art that other suitable alternative ways of removably connecting the housing sections 20, 21 , 22 can be used. Hence, the valve sleeve 2 can be readily and easily replaced without having to unfasten the countersunk screws rigidly connecting the pipe 3 to the mounting frame 7 or the fasteners rigidly connecting the piston assembly 5 to the mounting frame 7. In effect, the valve housing 6 creates a hollow space to accommodate and protect the mechanical pinching mechanism 4 and flexible sleeve 2 that is readily and easily accessible, and does not disturb the connections to the piping 3. [0027] The pinch bars 4a, 4b of the mechanical pinching mechanism 4 are slidingly movable along shafts 30 in a substantially vertical direction. The piston assembly 5 is operatively connected to a yoke 32 to control the movement of the pinch bars 4a, 4b along the shafts 30. To effect closure of the pinch valve 4, pressurised air is supplied to the pneumatic piston assembly 5, which forces the yoke 32 and hence the upper pinch bar 4a away from the support plate 18. This movement is accommodated by the upper pinch bar 4a sliding downwardly along shafts 30. When the upper pinch bar 4a contacts the flexible valve sleeve 2, further displacement of the piston assembly 5 causes drawing the lower pinch bar 4b upwardly to contact the valve sleeve 2 from the other side. Thus, the pinch bars 4a, 4b progressively move together and thereby reduce the cross-sectional area of the sleeve 2 in a self-centring manner. When the piston assembly 5 is reversed, the cross-sectional flow area is enlarged by a reverse of the above described process.

[0028] To replace the flexible sleeve 2 in this embodiment of the invention, the lower housing section 20 is removed to allow access to the interior of the valve housing 6 and the valve sleeve. The upper housing sections 21 , 22 are also removed to further enhance access to the interior of the valve housing 6, the valve sleeve 2 and the mechanical pinching mechanism 4. It will be appreciated that the lower housing section 20 and upper housing sections 21 , 22 can be removed in any order.

[0029] The lower pinch bar 4b is disassembled from the shafts 30 and then the nuts 16 and bolts 15 connecting the valve sleeve 2 to the interior mounting faces 14 of the mounting frame 7 are loosened and removed. The valve sleeve 2 can now be removed from the valve housing 6 and replaced with another valve sleeve 2. The new valve sleeve 2 is now connected or mounted to the mounting frame 7 via the bolts 15 and nuts 16 affixing the sleeve flanges 12 to the interior mounting faces 14 of the mounting frame. The lower pinch bar 4b is then reattached to the shafts 30 of the mechanical pinching mechanism 4. Thus, it can be seen that the valve sleeve 2 is easily and readily replaced without requiring loosening or removing the connections of the pipes 3 and the piston assembly 5 to the mounting frame 7. Thus, the pipes 3, mounting frame 7 and piston assembly 5 all remain in situ during the sleeve removal and replacement operation. In addition, the removal and replacement process is performed without disturbing the surrounding pipework.

[0030] Unlike the sleeve removal operation for pinch valves using a longitudinally split valve body, there is no need to reconnect the two halves of the valve body using bolts since the housings sections 20 to 22 slide into engagement with the mounting frame. Also, there is no need to provide for separate jacking bolts to maintain the connection between the pipes 3 and the upper half of the valve body. As such, the sleeve replacement procedure with the embodiment of the invention involves fewer steps than previously done with these types of pinch valves. As a consequence, it can thus readily be appreciated that the removal of the lower housing section 20 and upper housing sections 21 , 22 can be achieved rapidly and easily, so that the valve sleeve 2 and/or lower pinch bar 4b may be accessed for disconnection and replacement with minimum process stoppage time.

[0031] Also, by enclosing the mechanical pinching mechanism 4 within the valve housing 6, the embodiment of the invention has the advantage of being easier to manufacture, since there is no longer any need to fabricate the valve housing with slots to accommodate movement of the pinch bars 4a, 4b of the mechanical pinching mechanism.

[0032] In other embodiments, the invention is applicable to other types of mechanical- type pinching mechanisms other than pinch bars 4a, 4b. Also, while the preferred embodiment has been described as removing all the housing sections 20 to 22, it will be appreciated that any one of the lower housing section 20 and upper housing sections 21 , 22 can be removed to permit access to the interior of the valve housing 6 without requiring removal of the other two housing sections. This may be useful where the inspection of the valve sleeve 2 and/or mechanical pinching mechanism 4 is required as part of regular maintenance tasks. Also, the removable portions of the valve housing can instead be one or more side panels or sections, instead of or in addition to the lower and upper housing sections 20, 21 , 22.

[0033] It will further be appreciated that any of the features in the preferred embodiments of the invention can be combined together and are not necessarily applied in isolation from each other. For example, in one embodiment, the mounting frame 7 is integrally formed with one of the upper housing sections 21 , 22 so that only one upper housing section and the lower housing section 20 can be removed. Likewise, in another embodiment, only the lower housing section 20 can be removed and the upper housing sections are integrally formed with the mounting frame 7. Similar combinations of two or more features from the above described embodiments or preferred forms of the invention can be readily made by one skilled in the art. [0034] By providing a valve housing that encloses the flexible valve sleeve and a removable portion, the invention confers the advantages of enabling simple and quick access and removal of the sleeve because it is totally internal to the valve housing so that once access is gained the removal of the sleeve is much simplified. Consequently, the time required for removal and replacement of the sleeve is considerably shortened. In addition, by also enclosing the mechanical pinching mechanism, the manufacture of the valve housing is simplified and thus incurs less capital cost. Furthermore, the invention can be readily implemented to existing pinch valve arrangements. In all these respects, the invention represents a practical and commercially significant improvement over the prior art.

[0035] Although the invention has been described with reference to specific examples, it will be appreciated by those skilled in the art that the invention may be embodied in many other forms.