GB2123532A - Slide valve seal - Google Patents

Abstract

The slide valve is provided with a separate sealing structure 7 which surrounds the through flow opening of the valve casing in an annular fashion and which supports the seal proper 8. This sealing structure which is movable by means of a suitable closing mechanism can be operated independently from the pressure or differential pressure, respectively, present in the valve. The annular structure 7 is sealed to the valve casing by a bellows 9. <IMAGE>

Description

SPECIFICATION Slide valve The present invention relates to an improved slide valve having a slide valve casing and a through flow opening located in said casing, having further a valve disk which is movable perpendicularly to said opening between an open position and a closed position, and having a valve disk sealing means.

Generally known slide valves are designed as so-called wedge valve or sluice valve. The valve mechanism proper of such valves comprises more or less rigid plates which are supported often at their center movably by means of a joint.

Other known slide valves are provided in general with a valve mechanism consisting of a valve disk which carries the seal and a counterdisk for arresting against the valve casing portion located opposite of the valve seat side and a valve closing mechanism located between the two plates and consisting in turn of elbow levers, roller mechanisms or ball mechanisms. The drawback of the design of such valves is that the valve mechanism proper occupies a relatively large space and has a high weight which in turn detrimentally influences the closing time of the slide valve in view of the relative large masses which must be moved thereby. Furthermore, the closing mechanism must always take up the complete differential pressure.

Hence, it is a general object of the present invention to provide an improved construction of a slide valve which obviates the above mentioned drawbacks of the known valves to a large extent.

Another object of this invention aims at the provision of a new and improved slide valve which is extremely simple in construction and design, reliable in operation, economical to manufacture, and dependable in use.

Now in order to implement these and still further objects of the invention, which will become more readily apparent as the description proceeds, the slide valve of this development is manifested by the features of comprising an annular supporting member forming part of the sealing means and surrounding the through flow opening, which supporting member supports at its face surface facing the valve disk the valve seal proper and is joined at its opposite end to a bellows joined in turn to the slide valve casing, which sealing means comprises further an operating means intended to force the annular supporting member including the seal against the valve disk and the latter against the valve seat.

According to an embodiment of the invention the through flow opening is formed by the bore of the casing and a guide sleeve and leaving a lateral slot through the valve disk. The annular supporting member which supports the seal proper is located, thereby, within a circumferential chamber of the casing and surrounds the guide sleeve.

In such case the valve is preferably designed such, that the guide sleeve forming part of the valve casing bore is an extension of an end flange separate from the remaining casing and projecting into the casing.

According to a further embodiment the valve may be designed such that the guide sleeve forming part of the valve casing bore is a part of an insert piece located between two end flanges.

Due to both above described structural embodiments the sealing means can be dismounted from the valve casing, for instance, for maintenance or repair reasons at any time.

According to a suitable design such dismounting can be carried out without the need of dismounting the valve disk.

The bellows may consist of metal or of a plastics material and comprises preferably an own resetting force of such a value that as soon as the operating means has been brought into a corresponding operational position the annular supporting member which supports the seal disengages by itself from the valve sealing seat.

According to a further preferred embodiment the operating means of the sealing means is arrestable in the valve closed position.

In contrast to known slide valve designs the slide valve of this development may be provided with a valve disk having a thickness of a few millimeters only (a fraction of an inch) and accordingly may be operated at an extremely high speed. This in turn allows a closing off of the through flow bore within an exceedingly shorter time span.

Because the valve mechanism used with the structure designed in accordance with the invention must not transmit the entire forces of the pressure differentials, such mechanism can be designed to have a much smaller weight. Due to the structure in accordance with the invention no high tensions leading to wear will appear at any area.

Furthermore the inventive structure allows quite easily the use of valve disks made of nonmetallic materials such, for instance, valve disks made of glass which may be preferable for some applications.

The invention will be better understood and objects other than those set forth above will become apparent when consideration is given to the following detailed description thereof. Such description makes reference to the annexed drawings, wherein: Fig. 1 is a cut away portion of a cross section of a disk valve constructed according to the present invention; and Fig. 2 is a similar cutout illustrating a second embodiment of the slide valve designed according to the present invention.

Describing now the drawings, and considering initially the exemplary embodiment of the slide valve as shown schematically in Fig. 1, it will be understood that same comprises a slide valve casing 1, at one end of which an insertion flange 2 is provided. This flange 2 forms together with the residual casing 1 one unit. The flange 2 comprises an extension projecting towards within the casing, namely a guide sleeve 3. Between the inner face surface of the guide sleeve 3 and the casing part 4 there is provided the relatively narrow slot for the valve disk 5. This valve disk 5 may be made from a metal or glass or any suitable material. Depending from the prevailing differential pressure the valve disk 5 will abut either the valve seat area 4a of the casing 4 or the inner face surface of the guide sleeve 3.

In order to form a seal of the valve disk 5 a sealing means is located in an outer chamber 6 of the valve casing, which sealing means consists basically of an annular supporting member 7 for the sealing ring 8 proper. As already mentioned, this supporting ring 7 comprises at one face surface the sealing ring 8 and is mounted at the other end via a bellows member 9 to the casing 1 or flange 2, respectively. This bellows member 9 consists of a metal or plastics material and is preferably of a self-restoring design such that the supporting member 7 will be pulled without the influence of outer forces back into a position in which it does not abut the valve disk 5.

In general, the sealing ring or seal 8, respectively, consists of an elastomer or a plastomer. Under certain conditions also metallic materials are suitable for manufacture of the seal 8.

By means of a not particularly shown operating means (mechanism or hydraulic etc. device) the supporting member 7 including its seal 8 may be urged against the valve disk 5 if the valve disk 5 is in the valve closed position and whereby the valve disk 5 may, furthermore, be urged against the valve seat area 4a.

The advantage of this design is that in order to achieve a proper sealing of the valve in its closed position a force is necessary, which force corresponds to the necessary sealing force, which merely corresponds to the spring rate of the bellows and possible differential forces acting onto the bellows. This closing mechanism operates practically independently from the differential pressure exerted by the fluid flowing through the valve acting onto the valve disk, may this fluid be a gas, a liquid or a charge of a solid material lying on top of the disk.

In the shown design the valve disk 5 is located in an extremely narrow slot relative to the valve casing. This facilitates specifically the application of the slide valve together with bulky commodities.

The seal of the valve seat abuts always the valve disk 5 without any detrimental rubbing therebetween. If relatively high differential pressures are present from either side, the valve disk 5 will support itself initially always on the valve seat area 4a or the end of the guide sleeve 3.

Fig. 1 discloses clearly that the flange 2 may be dismounted from the casing at any time for a checking, maintenance or repair purposes. It is thereby necessary to dismount the slide valve from the installation, i.e. out of the pipe system, tube system etc. within which it is located.

This may be avoided when applying the design of the slide valve as illustrated in Fig. 2, which will be explained in detail below. This design allows a retrieving of the supporting ring 10 including the seal 1 the bellows 1 2 as well as the insert piece 1 3 supporting and guiding above structures sideways out of the valve casing after removal of the casing cover 14. According to this structure, above indicated parts 11-14 are mounted between two end flanges 15 and 16 belonging also to the complete casing. Thereby, the valve disk 1 7 is mounted in the same fashion as is the case of the valve disk 5 of the embodiment shown in Fig. 1.

Regarding the valve disks 5 or 17, respectively, of both embodiments it shall be repeated that such disk consists substantially of a thin plate designed to cope with the operating or differential pressure, respectively.

This valve disk 5 is moved into or out of its shut off position via a linear mechanism or a swinging mechanism.

Such mechanism, may it be a mechanically, electropneumatically or hydraulically acting operating device, is generally known in the art and thus not specifically shown.

As soon as the valve disk 5 or 17, respectively.

has arrived at the closed valve position, the supporting ring 7 or 10, respectively, will be moved by mechanicai, pneumatical or hydraulic members such, that the seal 8 or 11, respectively, will be pressed against the valve disk 5 or 1 7, respectively, and the latter against the valve seat area of the casing. This closing mechanism is preferably designed such that it remains locked in the closed valve end position, i.e. such that upon a failure of the respective control energy the valve will remain in this position.

While there are shown and described present preferred embodiments of the invention, it is to be distinctly understood that the invention is not limited thereto, but may be otherwise variously embodied and practiced within the scope of the following claims.

Claims (10)

1. An improved slide valve having a slide valve casing and a through flow opening located in said casing, having further a valve disk which is movable perpendicularly to said opening between an open position and a closed position, and having a valve disk sealing means, the improvement comprising an annular supporting member forming part of said sealing means and surrounding said through flow opening, which said supporting member supports at its face surface facing said valve disk the valve seal proper and is joined at its opposite end to a bellows joined in turn to said slide valve casing, which said sealing means comprises further an operating means intended to force said annular supporting member including said seal against said valve disk and the latter against the valve seat.

2. The improved slide valve of claim 1, in which said through flow opening is formed by the bore of said casing and a guide sleeve and leaving a lateral slot for said valve disk.

3. The improved slide valve of claim 2, in which said annular supporting member supporting said seal proper is located within a circumferential chamber of said casing and surrounds said guide sleeve.

4. The improved slide valve of claim 2, in which said guide sleeve forming part of the valve casing bore is an extension of an end flange separate from the remaining casing and projecting into said casing.

5. The improved slide valve of claim 2, in which said guide sleeve forming part of the valve casing bore is a part of an insert piece located between two end flanges.

6. The improved slide valve of claim 1, wherein said bellows consists of a metal.

7. The improved slide valve of claim 1, wherein said bellows consists of a plastics material.

8. The improved slide valve of claim 1, in which the restoring force of said bellows has such a value that as soon as said operating means has been brought into a corresponding operational position, said annular supporting member which supports said seal disengages by itself from the valve sealing seat.

9. The improved slide valve of claim 1, in which said operating means of said sealing means is arrestable in the valve closed position.

10. A slide valve substantially as hereinbefore described with reference to the accompanying drawings.