Abstract In a molecular pump comprising a pump vessel (11) having inlet and outlet ports (13 and 14), an axial-flow type molecular pump member (20) disposed near the inlet port, and an additional pump member (30) of a helical groove type disposed near the outlet port, the additional pump member comprises an inside cylindrical member (31) rotatable around a center axis of the pump vessel and an outside cylindrical member (32) held on an inner surface of the pump vessel. An additional cylindrical member (32a) is situated nearthe outlet port and brought into contact with the outside cylindrical member. The additional cylindrical member is separable into a plurality of separate pieces each of which is radially detachable from another. The additional cylindrical member is independent of the outside cylindrical member. Alternatively, the additional cylindrical member may be integral with the outside cylindrical member cut into separate pieces.
In a molecular pump comprising a pump vessel which has a center axis and an inner surface defining a hollow space along said center axis and which has an inlet port and an outlet port in communication with said hollow space, a first pump member comprising a plurality of rotor blade members rotatable around said center axis in said hollow space near said inlet port and a plurality of stator blade members held on said inner surface with said rotor blade members alternately interposed, and a second pump member comprising an inside cylindrical member near said outlet port and an outside cylindrical member held on said inner surface and having an inner peripheral surface parallel to said center axis and in a face to face relationship relative to said hollow space, said inside cylindrical member having an outer peripheral surface rotatable around said center axis with a predetermined distance left in said hollow space from said inner peripheral surface, either of said inner and said outer peripheral surfaces being provided with a helical groove, the improvement wherein: said outside cylindrical member is brought into contact with an additional cylindrical member situated nearer to said outlet port than said inside cylindrical member and cut into a plurality radially of separate pieces each of which is/detachable from another.
Claim 2
Dependent Claim
216 words
In a molecular pump comprising a pump vessel which has a center axis and an inner surface defining a hollow space along said center axis and which has an inlet port and an outlet port in communication with said hollow space, a first pump member comprising a plurality of rotor blade members rotatable around said center axis in said hollow space near said inlet port and a plurality of stator blade members held on said inner surface with said rotor blade members alternately interposed, and a second pump member comprising an inside cylindrical member near said outlet port and an outside cylindrical member held on said inner surface and having an inner peripheral surface parallel to said center axis and in a face to face relationship relative to said hollow space, said inside cylindrical member having an outer peripheral surface rotatable around said center axis with a predetermined distance left in said hollow space from said inner peripheral surface, either of said inner and said outer peripheral surfaces being provided with a helical groove, the improvement wherein: said outside cylindrical member is brought into contact with an additional cylindrical member situated nearer to said outlet port than said inside cylindrical member and cut into a plurality radially of separate pieces each of which is/detachable from another.
Claim 3
Dependent Claim
20 words
A molecular pump as claimed in Claim 1, wherein said additional cylindrical member is separable from said outside cylindrical member.
Claim 4
Dependent Claim
31 words
A molecular pump as claimed in Claim 1, whrein said additional cylindrical member is integral with said outside cylindrical member, said outside cylindrical member being also cut into said separate pieces.
Claim 5
Dependent Claim
22 words
A molecular pump as claimed in Claims 1, 2, or 3, wherein said helical groove is formed on said inner peripheral surface.
Claim 6
Dependent Claim
22 words
A molecular pump as claimed in Claims 1, 2, or 3, wherein said helical groove is formed on said outer peripheral surface.
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