Compound sliding seal unit suitable for atmosphere to vacuum applications

An atmosphere to vacuum compound sliding seal unit comprising:

• a fixed inner plate suitable for immovable attachment to and integration with a wall of a vacuum chamber, wherein said fixed inner plate has forward-facing and rearward-facing surfaces, preselected width and thickness dimensions, a limited length dimension, and a centrally disposed open slot whose span extends over at least one half of said limited length;
• a first intermediate plate positioned adjacent to and slideable on-demand over said forward surface of said fixed inner plate, wherein said first slideable intermediate plate has forward-facing and rearward-facing surfaces, prechosen width and thickness dimensions, a length dimension shorter than the limited length dimension of said fixed inner plate, and a first centrally disposed cavity zone whose span distance is substantially less than the span of the open slot in said fixed inner plate;
• a second intermediate plate positioned adjacent to and slideable on-demand over said forward-facing surface of said first intermediate plate, wherein said second intermediate plate has forward and rearward surfaces, prechosen width and thickness dimensions, a length shorter than said length dimension of said first intermediate plate, and a second centrally disposed cavity zone whose span size is less than the span distance of said first cavity zone in said first intermediate plate;
• an outer plate positioned adjacent to and slideable on-demand over said forward-facing surface of said second slideable intermediate plate, wherein said slideable outer plate has forward-facing and rearward-facing surfaces, predetermined width and thickness dimensions, a length dimension less than the length dimension of said second slideable intermediate plate, and a centrally disposed air-tight mounting suitable for the juncture and support of a feed-through member;
• a first sliding seal located between said forward-facing surface of said fixed inner plate and said rearward-facing surface of said first slideable intermediate plate, said first sliding seal surrounding and hermetically enclosing the perimeter of said open slot in said fixed inner plate;
• a second sliding seal located between said forward-facing surface of said first slideable intermediate plate and said rearward-facing surface of said second slideable intermediate plate, said second sliding seal surrounding and hermetically enclosing the perimeter said cavity zone in said first slideable intermediate plate;
• a third sliding seal located between said forward-facing surface of said second slideable intermediate plate and said rearward-facing surface of said slideable outer plate, said second sliding seal surrounding and hermetically enclosing the perimeter said cavity zone in said slideable intermediate plate;
• means for raising and lowering each of said first and said second slideable intermediate plates and said slideable outer plate on demand;
• and
• a feed-through member of set dimensions attached to said air-tight mounting of said slideable outer plate, whereby the axial length of said mounted feed-through member extends through said cavity zone of said slideable intermediate plates and said open slot of said fixed inner plate concurrently, and thereby passes from an atmospheric environment into a vacuum environment.

An atmosphere to vacuum compound sliding seal unit comprising:

• a fixed inner plate suitable for immovable attachment to and integration with a wall of a vacuum chamber, wherein said fixed inner plate has forward-facing and rearward-facing surfaces, preselected width and thickness dimensions, a limited length dimension, and a centrally disposed open slot whose span extends over at least one half of said limited length dimension;
• at least two discrete intermediate plates individually positioned adjacent to and slideable on-demand over said fixed inner plate, wherein each of said slideable intermediate plates has forward-facing and rearward-facing surfaces, prechosen width and thickness dimensions, a length dimension shorter than the limited length dimension of said fixed inner plate, and a centrally disposed cavity zone whose span distance is not greater than fifty percent of the span of said open slot in said fixed inner plate;
• an outer plate positioned adjacent to and slideable on-demand over a forward facing surface of the last of said discrete slideable intermediate plates, wherein said slideable outer plate has forward and rearward facing surfaces, predetermined width and thickness dimensions, a length dimension less than the smallest length dimension of said slideable intermediate plates, and a centrally disposed air-tight mounting suitable for the juncture and support of a feed-through member;
• a first sliding seal located between said forward-facing surface of said fixed inner plate and said rearward-facing surface of the most rearwardly placed of said slideable intermediate plates, said first sliding seal surrounding and hermetically enclosing the perimeter of said open slot in said fixed inner plate;
• a plurality of additional sliding seals which are located between said forward-facing surface for each of said slideable intermediate plates and a reward facing surface of a successive plate up to and including said outer plate wherein each of said additional sliding seals surrounds and hermetically encloses the individual perimeter of each said cavity zone in each of said slideable intermediate plates;
• means for raising and lowering each of said slideable intermediate plates and said slideable outer plate on-demand;
• and
• a feed-through member of set dimensions attached to said air-tight mounting of said slideable outer plate, whereby the axial length of said mounted feed-through member extends through each of said cavity zones in said slideable intermediate plates and said open slot of said fixed inner plate concurrently, and thereby passes from an atmospheric environment into a vacuum environment.

A unitary sliding seal arrangement suitable for use between a region of high pressure and a region of vacuum, said unitary sliding seal arrangement comprising:

• a preformed sealant article formed of slightly flexible, low friction material having good sealing and wear-resistance properties which can be interposed between a first plate and a second plate that can be moved relative to one another;
• and which can be nested in a recess on a surface of the first plate that bears against a surface of the second plate, wherein said sealant article
• (i) incorporates a plurality of annular flat sealing surfaces between which annular recesses are provided, said recesses being capable of connection to a source of differential pumping,
• (ii) bridges each recess and allows each of the annular sealing surfaces some independence of motion when sliding over such imperfections and deviations as then exist upon the surface of the second plate, and
• (iii) is urged against the second plate to form a plurality of substantially air-tight closures by means of each said annular flat sealing surface,
• (iv) allows said source of differential pumping to be applied between each said air-tight closure, and thereby allows reliable effective dynamic sealing between atmospheric pressure and high vacuum between surfaces in relative motion.