Slide valve

Abstract: A slide valve, especially for use in a compressed air supply installation, comprises a body (1) defining an inlet passageway (3) and an outlet passageway (4) and a vane (9) having an orifice therethrough and movable laterally relative to the passageways (3,4) between a valve-open position in which the orifice is in register with the passageways (3,4) thereby permitting fluid to flow through the valve, and a valve-closed position in which the orifice is wholly out of register with the passageways (3,4) thereby isolating the inlet passageway (3) from the outlet passageway (4). The vane (9) defines, at least in part, an exhaust passageway (15) that, in the valve-closed position, connects the outlet passageway (4) to atmosphere via a further exhaust passageway (16,17) formed in the body (1) whereby, in the valve-closed position, the downstream side of the installation will automatically become depressurised (Fig 2).

Description: This invention relates to fluid flow control valves and more particularly to so-called "slide valves" for use especially, but not exclusively, in compressed air installations. In compressed air installations, it is common practice to include one or more two-way (i.e. "on" or "off") isolating stop valves that are normally in their "on" position, i.e. when the installation is operational, but that can, when necessary, be manually turned off in order to isolate the upstream or downstream section of the installation for servicing purposes. Clearly, the or each section that requires servicing must be depressurised and, for that reason, the isolating valve, when in its "off" position, acts not only to interrupt the compressed air supply but also to exhaust air in the relevant section to atmosphere. Hitherto, a ball valve has commonly been used for that purpose. Such valves are, however, relatively expensive to produce because of the close tolerances required in the machining/moulding of the ball closure and the part-spherical seats associated with it. Some years ago, we introduced, as a more cost-effective alternative, a two-way slide valve, the essential features of which are recited in the pre-characterising clause of claim 1 hereof. The moveable vane of such valve incorporates an exhaust passageway terminating in an outlet orifice defined by the vane such that, in the valve's "off" position, the exhaust passageway is brought into communication with the upstream or downstream side, as desired, of the installation whereby air exhausts from one or the other side of the installation via the exhaust passageway and the outlet orifice. However, such valve has the disadvantage that it is not possible to fit an exhaust silencer or to pipe the exhaust air to a remote location. The present invention provides a two-way slide valve that overcomes that disadvantage by modifying our prior above-mentioned valve so that the outlet orifice for exhaust air is located in the valve body rather than in the vane. US patent No 4340203 describes a slide valve wherein, in one position, pressurised fluid at one of its ports can exhaust to atmosphere through an orifice defined in the valve body. However, the valve is a spring-biased, three-way valve and as such is of a quite different type and design from that with which the present invention is concerned. EPA 0324698, US patent No 3872889 and GB 2127940 also describe valves which in one position permit the exhaust of fluid through an orifice defined in the valve body. However, all of those are rotary disc valves, as distinct from slide valves, and so again are of a quite different type and design from that with which the present invention is concerned. According to the present invention, there is provided a two-way fluid flow slide valve comprising: a) first and second body parts secured together and defining, respectively, first and second, substantially central fluid flow passageways, said body parts further defining between them a cavity into which said fluid flow passageways open in register with one another, b) first and second substantially annular seals carried by said body parts and which surround said first and second fluid flow passageways respectively where they open into the cavity, c) a vane mounted in said cavity in abutment with said seals and having opposed ends that project from the cavity beyond the confines of said body parts, said vane having an orifice therethrough and being slidable, by the application of manual force to the appropriate one or other of said ends, within said cavity and thus laterally relative to said fluid flow passageways between a valve-open position in which said orifice in the vane is in register with said fluid flow passageways thereby permitting fluid to flow between said fluid flow passageways and a valve-closed position in which said orifice is wholly out of register with said fluid flow passageways whereby the vane prevents the flow of fluid therebetween, and d) a fluid exhaust passageway in said vane, which fluid exhaust passageway is, in the valve-open position, isolated from said fluid flow passageways but which, in the valve-closed position, connects one or other of said fluid flow passageways to atmosphere, characterised in that said first body part also has a further fluid exhaust passageway formed therein, said further fluid exhaust passageway having a first end that opens into said cavity adjacent to said first fluid flow passageway and a second end that opens to atmosphere, in that said first end of said further fluid exhaust passageway, where it opens into said cavity, is surrounded by a third, substantially annular seal carried by said first body part and with which the vane abuts, said third seal being unitary with said seal associated with the first fluid flow passageway so that there is a section common to the seals located between said first fluid flow passageway and the further fluid exhaust passageway where they open into the cavity and in that the fluid exhaust passageway in said vane comprises a channel formed in the surface thereof facing said first body part, said channel, in the valve-closed position, bridging said common section of the seals thereby to interconnect said first fluid flow passageway and said further fluid exhaust passageway so that fluid in said first fluid flow passageway will exhaust to atmosphere. The vane may slide in linear fashion in the cavity, but preferably it is pivotally mounted by the body and thus moves in an arcuate path. The surface channel formed in the vane may be straight, but it is preferably V-shaped for the reason explained later. The second end of the fluid exhaust passageway formed in the body preferably comprises a threaded port whereby a silencer or pipe connector may be threadedly coupled thereto. One embodiment of the invention will now be described in more detail, by way of example only, with reference to the accompanying drawings, in which: Fig. 1 is an isometric view of the valve in its closed position; Fig. 2 is a plan view, partly in section, of the valve shown in Fig. 1, again showing the valve in its closed position; Fig. 3 is a view on the line III-III of Fig. 2, again with the valve in its closed position; and Fig. 4 is a similar view to that of Fig. 3 but showing the valve in its open position. Referring to the drawings, the valve comprises a body 1 made in two halves la and 1b joined together by, for example, bolts (not shown). The two body halves 1a and 1b define centrally between them a generally rectangular cavity 2 from which extends, in the part 1a, a cylindrical inlet passageway 3 and, in the part 1b, a cylindrical outlet passageway 4. The inlet and outlet passageways 3, 4 terminate at their outer ends respectively in ported flanges 5 and 6 whereby the valve may be incorporated downstream, for example, of a filter, lubricator, regulator assembly (not shown) of a compressed air installation using suitable clamping devices. The two opposed faces of the body parts 1a and 1b have respective annular recesses formed in them circumscribing passageways 3 and 4 and in which rubber seals 7 and 8 respectively are located. The cavity 2 has a vane 9 pivotally mounted, at 10, in it, the extremities 11, 12 thereof being enlarged in order to facilitate manual actuation of the valve. The vane 9 has an aperture 13 formed through it, whose overall diameter corresponds to that of the passageways 3 and 4, and which is divided into two substantially semicircular sections by a member 14. The surface of the vane 9 facing the body part 1b is further formed with a V-shaped exhaust channel 15 which, when the valve is in its closed position (as is described in more detail below) connects the outlet passageway 4 to an exhaust passageway 16 formed in the body part 1b, the passageway 16 terminating in a threaded exhaust port 17 with which a silencer or exhaust pipe-line connector (not shown) may be engaged. The entrance to the exhaust passageway 16 is surrounded by a seal 8' which in fact is formed integrally with the seal 8 and which sits in an annular recess formed in the body part 1b. Figs. 3 and 4 show, in section, the seals 8 and 8' which, as can be seen, are in the shape of a figure 8 and which, for stability, may comprise an elastomer, such as a nitrile rubber, bonded to a steel insert. The valve operates as follows. Referring specifically to Fig. 4, this shows the valve in its open position with the aperture 13 in complete register with the passageways 3 and 4. The seals 7 and 8, which are slightly compressed by the vane 9, ensure that the path between the passageways 3 and 4 is fluid-tight. The valve may be closed by depressing the enlarged end 12, as shown by the arrow A in Fig. 4, whereupon the vane 9 pivots about the mount 10 in a downward direction. In the closed position, the V-shaped channel 15 interconnects the outlet passageway 4 with the exhaust passageway 16 formed in the body part 1b and hence with the atmosphere, whereas the inlet passageway 3 is closed off by the vane 9 - see Figs. 2 and 3. Accordingly, compressed air in the outlet (downstream) side of the installation will exhaust to atmosphere. Whilst the exhaust channel 15 could, in principle, be straight, we have found it preferable to make it V-shaped so that, during movement of the vane 9, the seal 8' is always adequately supported and will not be dislodged by the differential air pressure across it which could otherwise interfere with smooth movement of the vane 9. The member 14 extending diametrically of the aperture 13 serves a similar purpose. Further, the V-shaped channel 15 is disposed on the surface of the vane 9 relative to the aperture 13 such that the inlet passageway 3 will be substantially completely closed off before the channel 15 interconnects the outlet passageway 4 with the exhaust passageway 16. As will be appreciated, the valve specifically described above could be arranged to exhaust the inlet (upstream) side of a compressed air or other fluid supply installation, if desired. Further, the V-shaped channel 15 could, in an alternative construction (not shown), communicate with a small through-bore formed in the vane 9 through which the exhaust air passes to atmosphere via the further exhaust passageway formed in the valve body. Finally, and as is conventional, the vane 9 may be formed with a pair of peripheral apertures (not shown) that enables the valve to be locked in its open or closed position, as the case may be, by means of a padlock or other locking device.

Claims: A two-way fluid flow slide valve comprising: a) first and second body parts (1b,1a) secured together and defining, respectively, first and second, substantially central fluid flow passageways (4,3), said body parts (1a,1b) further defining between them a cavity (2) into which said fluid flow passageways (3,4) open in register with one another, b) first and second substantially annular seals (7,8) carried by said body parts (1a,1b) and which surround said first and second fluid flow passageways (3,4) respectively where they open into the cavity (2), c) a vane (9) mounted in said cavity (2) in abutment with said seals (7,8) and having opposed ends (11,12) that project from the cavity (2) beyond the confines of said body parts (1a,1b), said vane (9) having an orifice (13) therethrough and being slidable, by the application of manual force to the appropriate one or other of said ends (11,12), within said cavity (2) and thus laterally relative to said fluid flow passageways (3,4) between a valve-open position in which said orifice (13) in the vane (9) is in register with said fluid flow passageways (3,4) thereby permitting fluid to flow between said fluid flow passageways (3,4) and a valve-closed position in which said orifice (13) is wholly out of register with said fluid flow passageways (3,4) whereby the vane (9) prevents the flow of fluid therebetween, and d) a fluid exhaust passageway in said vane (9), which fluid exhaust passageway is, in the valve-open position, isolated from said fluid flow passageways (3,4) but which, in the valve-closed position, connects one or other of said fluid flow passageways (3,4) to atmosphere, characterised in that said first body part (1b) also has a further fluid exhaust passageway (16) formed therein, said further fluid exhaust passageway (16) having a first end that opens into said cavity (2) adjacent to said first fluid flow passageway (4) and a second end (17) that opens to atmosphere, in that said first end of said further fluid exhaust passageway (16), where it opens into said cavity (2), is surrounded by a third, substantially annular seal (8') carried by said first body part (1b) and with which the vane (9) abuts, said third seal (8') being unitary with said second seal (8) so that there is a section common to the seals (8,8') located between said first fluid flow passageway (4) and the further fluid exhaust passageway (16) where they open into the cavity (2) and in that the fluid exhaust passageway in said vane (9) comprises a channel (15) formed in the surface thereof facing said first body part (1b), said channel (15), in the valve-closed position, bridging said common section of the seals (8,8') thereby to interconnect said first fluid flow passageway (4) and said further fluid exhaust passageway (16) so that fluid in said first fluid flow passageway (4) will exhaust to atmosphere. A slide valve according to claim 1 wherein the vane (9) is pivotally mounted in the body (1) and thus slides within the cavity (2) in an arcuate path. A slide valve according to claims 1 or claim 2 wherein the channel (15) in the vane (9) is substantially V-shaped. A slide valve according to any one of claims 1 to 3 wherein the said second end of the further fluid exhaust passageway (16) comprises a threaded port (17) whereby a silencer or pipe connector may be threadedly coupled thereto.

Inventors: HARROLD MARTYN JOHN, HARROLD, MARTYN JOHN
Applicants: IMI NORGREN LTD, IMI NORGREN LIMITED
Application year: 1995
Main classification: F16K11
IPC codes: F16K3, F16K11