3.6.4 Gate valves
While the above described valves only partially release the nominal cross-section, gate valves offer a free passage in an open position. Together with their low installation height, it leads to high conductance and with that the required minimal performance losses during the use of high vacuum pumps
Valve plates, usually of dual design, move back and forth to open and close these valves. In the closed position, both elements are forced apart and against the sealing surfaces by means of balls. Depending upon the direction of movement of the valve gate, a distinction is made between rebound valves, shuttle valves and rotary vane valves. While most gate valves can seal against a differential pressure of 0.1 MPa on the valve plate due to their special design, they can only open in the presence of a low differential pressure on the valve plate.
Figure 3.23: UHV gate valve