Valves and valve actuation – Rotary valves
Patent
1991-11-20
1992-12-15
Fox, John C.
Valves and valve actuation
Rotary valves
251 87, 251314, F16K 500
Patent
active
051709929
DESCRIPTION:
BRIEF SUMMARY
The present invention relates to a stop valve of the type having a cup-shaped valve body cooperable with an annular seat in the flow passage and rotated about an axis perpendicular to the flow passage. The valve body is rotated in the housing by a spindle having a handle outside the housing.
The cap-shaped valve body of such valves causes a few problems, which are hard to remedy. The cap e.g. is to cooperate with a seal during an extended period of time, resulting in a preferably constant sealing action. Also, the pressure of the medium, which is to be controlled, must not open up/shut the valve body unintentionally. To the extent that there is no unambiguous exterior indication of the position of the valve body, it is difficult to know the precise control position. Another problem resides in the fact, that it often is desirable to be able to control a flow in opposite directions, while the desirable properties of the valve are maintained. An additional almost paradoxical problem is that the valve body, i.e. the cap, is to provide a satisfactory sealing irrespective of the direction of flow and the pressure of the medium and yet be easily controllable. Finally, the conventional stop valves require often a lengthy, tedious and expensive mounting process, a so called automatic mounting being almost impossible. Despite this length, tedious and expensive process several of the known valves constitute safety risks, since leakage and/or disintegration under pressure may occur.
A valve of the stated type is previously known by U.S. Pat. No. 4 257 576. The concept of this previous invention is to design a shut-off member large in relation to a passage way into which it is to be fitted through one of two connecting ends of a valve housing which is made in one piece. FIG. 16 of this specification reveals the way of mounting the shut-off member within the valve housing. As can be seen, the shut-off member has to be obliquely engaged in the main bore of the valve housing until an upper lug of said member arrives within a diverting spindle bore, while a lower, forked lug has to be engaged on a stub which previously has been secured to the housing as has a sealing gasket provided to co-operate with the shut-off member. Then, the latter is to be straightened rocking into a non-operative position, which is the only way to insert the shut-off member, which then has to be turned 180.degree., whereupon the spindle is inserted on to the upper lug.
It can hardly be argued, that such a concept requires a fair amount of difficult and time consuming manual assemblance work. In spite of this, the mode of operation and reliability of a valve of this kind must be questioned. Firstly, when having succeeded to insert the shut-off member, straightening and turning it to its right shut-off position, this will have to be achieved against resistance and friction offered by the sealing gasket, most probably manually, as the spindle is to be inserted but after the 180.degree. turn of the shut-off member. Anyway, it would hardly be possible to insert the spindle before, as the shut-off member is designed to be turned 90.degree. only. This means, that there must be a considerable play between gasket and shut-off member in order to have the latter slide along the gasket with the aid of a hand or some tool only. Secondly, the fork-shape of the lower lug, which shape is a must, is a considerable disadvantage, as in this way the shut-off member can exert an uncontrolled pressure on the gasket and damage or even blow away same at occasional high pressures like an ordinary shock-wave, which in a lever-like way is concentrated just and only on the gasket area juxtaposed the lower lug. Simultaneously, the upper lug may be damaged, if not the entire shut-off member. Undoubtedly, due to this design, there is a high wear of the said gasket region, and sooner or later the gasket sealing won't operate any longer in the desired way. With the wore-off gasket region, the shut-off member won't attain a straight position any longer, but will be more and more o
REFERENCES:
patent: 3326514 (1967-06-01), Riley
patent: 3379408 (1962-04-01), Lowrey
patent: 4006883 (1977-02-01), Hilsheimer
patent: 4150811 (1979-04-01), Condit
patent: 4193578 (1980-03-01), Brumm
patent: 4218042 (1980-08-01), Eckel
patent: 4260129 (1981-04-01), Groenfeld
patent: 4399976 (1983-08-01), Legris
patent: 4506696 (1985-03-01), von Pechmann
patent: 4822000 (1989-04-01), Bramblet
Fox John C.
Tour & Andersson AB
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