Valves and valve actuation – Hermetic flexible wall seal for actuator – Bellows
Patent
1997-02-18
1998-10-27
Chambers, A. Michael
Valves and valve actuation
Hermetic flexible wall seal for actuator
Bellows
251356, 251267, F16K 3100
Patent
active
058268561
DESCRIPTION:
BRIEF SUMMARY
The invention relates to a tap-fitting housing according to the precharacterizing clause of the main claim.
BACKGROUND OF THE INVENTION
Tap fittings usually have an actuation spindle, with the aid of which a closing element within the tap-fitting housing can be changed in its position. In the case of lift valves, irrespective of whether turning or rising spindles are involved, one end of the bellows is usually connected to the closing element and the other end of the bellows is fastened in a sealing manner within the housing. The bellows is intended to prevent a medium within the housing from passing through a housing opening surrounding the spindle.
Different means are known for fastening the end of the bellows on the housing side. GB-A-2 012 394 discloses so-called support rings, which are clamped by their outer diameter in a sealing manner between a tap-fitting housing and a cover closing the tap-fitting housing. On the side of the support ring facing the shut-off member, the bellows is welded on in a sealed manner. The shut-off member, actuation spindle, bellows and support ring are inserted as a prefabricated structural unit into the tap-fitting housing from outside. By means of screwing elemets and additional seals, the support ring is subjected to a pressing and sealing action between the housing and the cover. However, since these seals and the screwing elements have a plastic settling behaviour, the prestressing may be lost over the course of time. To be assured of a good seal of the housing, it is therefore essential to check the screwing elements from time to time for their prestressing and to retighten them if need be. To avoid this problem, it is also known to weld the end of the bellows on the housing side directly to the housing cover. Then, however, the housing cover nevertheless has to be braced against the housing in a sealing manner by means of a separate flat gasket with the aid of screwing elements, for example cover screws. Even then, the cover screws and their prestressing have to be checked from time to time in order to ensure adequate sealing tightness. It is also known to weld the housing cover to the housing. The welding of the end of the bellows on the housing side onto the housing covers is to this extent not entirely unproblematical, since here the weld has to be provided in a region of a transition between a small diameter and a large diameter and therefore the positioning of the welding torch requires particular care.
SUMMARY OF THE INVENTION
The invention is based on the problem of ensuring for tap-fitting housings sealed by bellows a reliable and simple installation of the bellows. The solution to this problem provides that the end of the bellows on the housing side is connected in a sealed manner to a sleeve surrounding the spindle. With approximately equal diameters, the sleeve can be welded very simply to the end of the bellows on the housing side, it being possible for this to be performed with the aid of a simple device. The outside diameter of the sleeve is in this case dependent on the installation conditions, the installation equipment and the loading situation of the bellows and also the dimensions of the bellows resulting from this.
In the cases in which the spindle with bellows attached thereto is led through the housing opening to be sealed, the sleeve usually has the same outside diameter as the bellows, but, for the purpose of more simple installation, will have a somewhat greater diameter than the bellows. However, in cases in which installation is performed from the inside of the housing, the sleeve may also have a smaller outside diameter than the bellows. This is dependent on the types of installation used and on the given conditions with respect to space.
According to one refinement of the invention, the sleeve can be introduced into the housing in a sealing manner. This may be performed, for example, by compressing a rim of the sleeve with the surrounding part of the housing or by providing welding seals. Further refinements of the invention provi
REFERENCES:
patent: 490589 (1893-02-01), Massey, Jr.
patent: 2317422 (1943-04-01), Thomsen
patent: 2912867 (1959-11-01), Gallant
patent: 4166607 (1979-09-01), Webb
patent: 5178365 (1993-01-01), Bartoschek et al.
Illy Alois
Ruckert Heinz-Juergen
Stock Hans-Georg
Chambers A. Michael
KSB Aktiengesellschaft
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