Cryosurgical probe with vacuum insulation tube assembly
A vacuum insulation tube assembly which is utilized as a component in a cryosurgical probe. The vacuum insulation tube assembly includes an inner tube; and, an outer tube concentrically positioned about the inner tube. The outer tube is securely soldered at end portions of the inner tube and forms a vacuum space between the inner tube and the outer tube. The vacuum tube assemblies may be conveniently mass produced using a special fixture.
1. A fixture for use in manufacturing a vacuum insulation tube assembly for a cryosurgical probe, comprising:
a) a generally cylindrical vacuum chamber having an upper end, a lower end, and a central axis;
b) a bottom plate positioned within an interior volume of said vacuum chamber, at said lower end, said bottom plate comprising a plurality of spaced elongated bottom plate openings extending therethrough substantially parallel to said central axis;
c) a guide plate assembly securely supported within said interior volume, at said upper end, said guide plate comprising a plurality of spaced elongated guide plate openings extending therethrough substantially parallel to said central axis;
d) a support plate securely positioned within an intermediate portion of said interior volume, said support plate comprising a plurality of spaced elongated support plate openings extending therethrough substantially parallel to said central axis; and,
e) a cover assembly mountable on said upper end of said vacuum chamber for providing access to said vacuum chamber for a plurality of inner tubes and outer tubes that are used to form vacuum insulation tube assemblies;
wherein said bottom plate openings, said guide plate openings, and said support plate openings provide access for insertion of the outer tubes and the inner tubes, said lower end of said vacuum chamber having a vacuum conduit in fluid communication with lower ends of the vacuum tube assembly, for connection to a vacuum source for evacuating fluid in spaces between the outer tubes and the inner tubes when concentrically positioned, ends of each respective tube assembly being soldered during operation of said fixture to form the vacuum tube assemblies.
2. The fixture of claim 1 , wherein said cover assembly, comprises:
a) a cover element including a circular main portion and a central portion having a circular flange; and,
b) an ejector plate assembly securely positionable on the end of said circular flange.
3. The fixture of claim 1 , further comprising a plurality of guide pins securely positionable within said vacuum chamber for supporting said bottom plate, said guide plate assembly and said support plate in their respective positions.
4. The fixture of claim 1 , wherein said guide plate assembly further comprises a plurality of tapered slider assemblies, each comprising:
a) a spring positioned within a recessed portion of an associated guide plate assembly opening;
b) an elongated tapered slider element positioned within said spring, an upper portion of an internal surface of said tapered slider element being tapered; and,
c) a retainer ring positioned within said guide plate assembly opening for retaining said elongated tapered slider element.
5. The fixture of claim 4 , further comprising a plurality of o-ring plunger assemblies, each comprising:
a) an o-ring plunger element operatively positionable within said internal surface of said elongated tapered slider element for urging an o-ring into a desired position between said outer tube and said inner tube; and,
b) an o-ring insert pin operatively positionable within said o-ring plunger for supporting said o-ring.