GB857342A - Mechanism for moving a member axially within a bore formed through the wall of a vessel - Google Patents

Abstract

857,342. Tuning cavity resonators. MULLARD Ltd. Oct. 29, 1957 No. 33678/57. Class 40(8). [Also in Group XL(a)] The tuning device of a klystron or other movable member of a vessel, which is movable axially within a circular bore formed in the wall thereof, comprises a bush 1 secured rigidly to the external surface of the wall of the vessel, a circular bore in the bush 1 forming a coaxial continuation of the vessel bore, a cylindrical sleeve 2 secured to the bush 1 and fitting tightly within the vessel bore, a tuning rod 14 sliding within sleeve 2 and having a copper head 4, the upper end of rod 2 projecting beyond bush 1 and sleeve 2, and a mechanism (not shown) preferably as disclosed in Specification 819,109 is provided for moving the tuning head 4 and rod 14 relative to the bush 1. Vacuum is completed by a bellows 19. In manufacture, the klystron has seating surface 16 formed thereon and a member to form bush 1 is brazed thereto. The klystron is now machined to the required dimensions. Now, using the internal surface of the klystron as a reference surface bush 1 . and member 6 are precision bored to the required final dimensions. Then using the bores of bush 1 and member 6 as a reference surface, the external shape of the bush 1 is formed by machining. The sleeve 2 is now inserted as a tight fit in bush 1 and in the bore in 26 and brazed at its upper end to bush 1 at 21, and bellows 19 is brazed to bush 1. The tuner rod 7 and head 4 are now inserted through the bellows 19 end and the bellows is sealed to to the upper end of the tuner rod. The adjusting mechanism is then attached to the upper end of the rod 7 and is in fact housed in tuning barrel 3 which is secured by screws 23 to bush 1. Since sleeve 2 projects inside the klystron it can be used to locate a cavity resonator inside the klystron. The lower end of the tuner rod 7 can be so profiled as to act as a #/4 choke. Bush 1 and sleeve 2 can be integral, using a material suitable for brazing or welding to the body of the klystron. A stop 17 on the tuner rod limits the downward movement thereof by abutting on the end of sleeve 2. Sleeve 2 is of Cr-Fe or Ni-Cr-Fe alloy the inner surface of which is highly polished to allow free movement of the tuner rod. Tuning rod 7 is of Cu or Cu-Ni alloy and bush 1 is of Cu-Ni alloy, Mo or non magnetic stainless steel, the joints at 29 and 16 being made by brazing. 15, 37 are exhaust bores.