Valves and valve actuation – Reciprocating valve – Actuator controlled stem seal
Patent
1992-02-14
1993-10-05
Rosenthal, Arnold
Valves and valve actuation
Reciprocating valve
Actuator controlled stem seal
251312, 251356, 251 77, F16K 136
Patent
active
052497755
DESCRIPTION:
BRIEF SUMMARY
This invention relates to closures for preventing gas or liquid flow, and particularly but not exclusively to stop valves and shaft seals.
In many types of conventional valve, a torque is applied to a spindle, in order to press a closure member against a sealing seal. The magnitude of the torque required is much greater than the pressure of the flow which is being controlled. Furthermore, even if the pressure of the flow remains unchanged, but the surface area of the seal and seat increase, the force required to operate the closure member will increase by several times. As a result, as the pressure of the flow and the diameters of the inlet and outlet to the valve increase, it becomes essential that components of the valve should be made to be stronger. Accordingly, a heavier valve body and a stronger spindle are required, and also, a heavy-duty packing gland is used. However, it is impossible to ensure that when the pressure of flow increases, the valve will not leak. In addition when a conventional valve, such as the one described above is used, the packing gland has to be repacked after use, or the valve will leak.
Furthermore, a conventional valve having more than 100 mm gate diameter requires a gear box or a powerful motor to operate the valve, and as the size of the valve increases, control of the valve becomes more difficult. This particular problem is essentially caused by the pressure of the flow, the size of the inlet and outlet to the valve and the stiffness of the packing gland.
The present invention sets out to provide-a closure suitable for use in valves, seals, shaft seals and other pressure systems, wherein no pressure means are required to press the sealing elements of the closure against a sealing seat, and no shaft packing material needs to be used. Furthermore, the invention sets out to provide a closure which may be relatively large, but may be operated by a relatively small drive spindle without the use of a gearbox or a motor.
According to one aspect of the present invention there is provided a closure for a gas or liquid system, capable of use as a stop valve component over a wide range of pressures in the system and as an anti-leakage seal, and comprising an outlet for the gas or liquid, and a closure element locatable to seat and seal in and around the said outlet, in which: the outlet comprises a shoulder recess formed in a face, the effective base of the recess and the said face being parallel and at accurately predetermined spacing; and the closure element comprises (a) a rigid disk-like member of accurately predetermined thickness to lie within a recess with an outer face exactly coplanar with the said face and (b) a flat or sheet-like deformable seal member held so as to lie on the said outer face of the disk and on the first said face.
In one preferred embodiment of the present invention the deformable seal member is attached in use to the rigid disk-like member, and the closure element thus constituted is movable with its disk-like member passing into or out of the recess to constitute a stop valve element for closing a duct opening through the base of the recess.
In a further preferred embodiment of the present invention, the deformable seal member is attached in use to the first-mentioned face and the closure thus constituted locates to constitute a sealing element, e.g. a shaft or spindle seal.
In the case of a shaft or spindle seal, it will usually be important to ensure that the components of the seal are not subjected to any significant axial force. Accordingly, it may be desirable that the region of the shaft of spindle provided with a seal embodying the invention is coupled to the remainder of the shaft of spindle, or to associated components, by couplings permitting axial relative movement while ensuring transmission of rotation, for example splines, square or hexagonal tees, and so on.
According to the present invention there is also provided a stop valve assembly comprising (a) as a stop valve element for the gas or liquid flow, a closure in one form as described
REFERENCES:
patent: 941652 (1909-11-01), Rock
patent: 1452811 (1920-04-01), Mueller
patent: 2876987 (1959-03-01), Renfro
patent: 3081792 (1963-03-01), Hansen
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