Bellows seal
OwnerAnton Brauninventor
Life of this patent
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Abstract
A bellows seal apparatus for use in compressors or the like which has pump means arranged and controlled to maintain a desired pressure differential between the inside and outside surfaces of the bellows. It also has a driving mechanism having a connection with a movable end of the bellows and an additional connection or connections with said bellows at unequally spaced points intermediate to the ends of the bellows to provide the least maximum stress levels in the bellows convolutions of each and thus the maximum life expectancy for the seal. The driving mechanism may take many forms but is so designed that it will elongate and contract each section of the bellows a distance depending upon the dynamically caused stresses in each section and the composition of and the number of bellows convolutions in each section.
Claims18
Control apparatus for a bellows seal on a reciprocable shaft comprising means for substantially balancing gas pressures on the inside and the outside surfaces of the bellows seal, means for dividing convolutions of the bellows seal into a plurality of sections of unequal numbers of convolutions which sections decrease in number of convolutions sequentially from a fixed end of the bellows seal to a movable end thereof, and movable driving means extending between said shaft and said movable end and between said shaft and the means dividing the convolution sections to concurrently actuate said movable driving means when said shaft is moved so as to elongate or shorten the length of each section an amount substantially proportional to the number of convolutions in each section.
Control apparatus for a bellows-type of hermetic seal around a reciprocable shaft, said seal having a fixed open end and a movable end and having an inside surface exposed to ambient pressure around said apparatus and an outside surface and being contained within a pressure chamber providing external pressure on said seal and being subject to potentially harmful differentials between external pressures and internal pressures, said apparatus comprising a first means for establishing a sub-ambient pressure and valve means for connecting said sub-ambient pressure in said first means to one of said surfaces when pressure thereon is higher than desired with respect to the pressure on the other side, whereby each of the pressures inside and outside of said bellows seal is maintained at its desired level and means to concurrently actuate said movable end and an intermediate portion of the seal.
Dependencies are inferred from the claim text.