The Holweck demountable type valve

The paper briefly describes the Holweck molecular pump and, in more detail, 10- and 30-kW Holweck demountable type valves. Precautions necessary with demountable valve installations are pointed out. The chief advantages are ability to renew filaments at a cost of a few pence, and ability to carry large overloads. Some results obtained with installations employing demountable valves are given. The possibility of larger-power single units being developed is mentioned, but short-wave work may make it unnecessary to build larger units than those developed. Perfection of details with a view to complete reliability should make for increased application of this type of valve.