Connection to vacuum systems

The partial flow concept is usually used in making the connection of a helium leak detector to vacuum systems with multi-stage vacuum pump sets. When considering where to best make the connection, it must be kept in mind that these are usually small, portable units which have only a low pumping speed at the connection flange (often less than 1 l/s). This makes it all the more important to estimate - based on the partial flow ratio to be 

Splitting of the gas flow (also of the test gas ) in accordance with the effective pumping speed at the partial flow branch point 

Partial flow ratio = Fraction of the overall flow to the leak detector 

B) Response time tj . = 3- = 3-Estimate Value for S, V and yare uncerlain cerlain calibrate with reference leak 

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Figure 6 Apparatus for determination of vapour pressure by dynamic method, A, Monel boiler provided with central thermometer pocket B, aluminium tube-oven C, coupling linking metal connecting tube to glass D, mercury-filled manometer connected to oil-filled line leading to piston gauge E, glass valve with PTFE stem Fisher and Porter Company, U.S.A.) F, reservoir for introduction of the sample G,H, electrical heater windings K,L, control resistor windings, insulated by suitable wrappings from G and H M, platinum resistance thermometer N, connection to vacuum system...

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