REPLACEMENT GOLD SEAL NOSEPIECE KIT204014 GP

GRANVILLE PHILLIPS REPLACEMENT GOLD SEAL NOSEPIECE KIT W/ TWEEZERS P/N 204014

Granville-Phillips 204 gold seal ultrahigh vacuum valve.Granville-Phillips Gold Seal Valves have been designed for industrial and research vacuum applicati** requiring maximum cleanliness and reliability at a reasonable cost. These valves will smoothly control all gases which are non-corrosive to both gold and Type 304 Stainless Steel. The range of this control extends from the lowest pressures attainable to above one atmosphere.Proven in Granville-Phillips bakeable metal valves since 1957, our unique seal design provides one of the longest seal lives presently available in UHV valves. Granville-Phillips gold seal c**truction exhibits negligible deformation with use under clean conditi** as compared with other UHV valves which shear the sealing metal each time the valve is closed. The advantages are reliable sealing for hundreds of valve operati** without the necessity of seal replacement and much lower gas release during sealing than is exhibited by deformable seals.The bakeable feature, open or closed, is beneficial to the user who desires to take full advantage of the widely used vacuum bakeout method of rapidly attaining very low pressure.The Granville-Phillips''''philosophy of minimizing contamination through material selection is evident in the choice of gold for the sealing medium and specially processed Type 304 Stainless Steel for all other valve components. These low vapor pressure materials and the absence of elastomers of any kind assure you of the cleanest valve c**truction possible. Ordinary bar stock with its inherent stringers, pipes, and porosity is never used in Granville-Phillips'''' UHV products. The gold seal is more resistant to oxidation than the more conventional copper seals. Superficial oxidation of the stainless steel portion of the seal will not harm the seal. The reliability of the Granville-Phillips'''' gold seal has been proven by repeated mass spectrometer leak tested seals against one atmosphere of helium both before and after 450°C UHV bakeout.Granville-Phillips''''surface physicists have found that in an unbaked organic or metal seal valve, mass spectrometer leak tight seals are produced primarily by minute water and/or oil films on the valve sealing surfaces-films that form on clean, well baked out surfaces after only a few minutes exposure to ordinary clean laboratory air. When these films are removed, as they are when a surface is subjected to ordinary UHV bakeout, the leakage conductance invariably increases by a factor of 1,000 to 10,000 times. Thus a valve seal design that relies on these contaminationfilms for sealing will be unsuitable for UHV use after vacuum bakeout. Granville-Phillips'''' valves do not depend on contamination films for sealing and are guaranteed to have a leakage conductance of less than 10-13liter/second even after a 450°C vacuum bakeout.Should the gold seal inadvertently be damaged through accidental admission of hard particles into a system, such as oxide flakes, lint, or zeolite, it may easily be replaced. The expense and time of a factory rebuild is thereby avoided and experimental or production work is subjected to only a minimum delay.