The Scrollvac plus silencer reduces exhaust noise during pump down and gas ballast operation and collects and retains tip seal dust as the pump is operated. Exhaust gases exit the exhaust port when the pump is being used to evacuate a process chamber, when the gas ballast control is being used, or both. The noise level when pumping down rises as the throughput increases and the silencer is used to reduce this noise level. The outer can is made of pressed steel and is split to allow access to the filter elements. The filter element housing is made from SantopreneŽ thermoplastic elastomer. The element itself is polyester. The foam block is manufactured from filter foam. Note: These elements can only be used in dry applications and must not be allowed to moisten. A pressure relief valve is not fitted to the silencer.