This week, the environmental group Climate Direct Action is prompting its supporters to hold “house parties” around the nation to hear from “valve turners,” what the group calls the next wave of ...
The 'R' Valve was developed from the French hard vacuum valve of WW1 and was made in the UK from 1916 by the Marconi Osram Valve Company. Its use in new equipment declined in 1925 with the ...
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