| 摘要 |
A cryosurgical instrument employing a standard, double-walled, metal vacuum bottle or dewer has a collar metallurgically bonded to the top of the dewer near the mouth thereof to provide machined threads for releasably engaging the delivery and control portion of the instrument to the reservoir portion of the instrument. The collar provides additional strength and support to the portion where the two walls of the dewer are joined to each other. A vent is provided in a bottom cap of the vacuum dewer. A valve directly in the cryogen delivery line is connected by a stem to a fulcrumed operating handle; a 360 DEG fulcrum is used, to permit rotating the handle for thumb or finger operation with either the right or the left hand, as desired; rotation of the handle also rotates the valve stem so as to assist in freeing it from crystalline adhesion which may result from moisture in the cryogen or in the ambient air. In one embodiment, the 360 DEG fulcrum has a cam surface which can be positioned wherever it is desired to cause the operating handle to be locked into the on position, regardless of its position of rotation. The fulcrum is adjustable for the relationship between the motion of the handle and the operation of the valve.
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