Pressure Differential Gate Valve
A 1 1/2 in isolation gate valve was designed and built to prevent vacuum vessel letup to atmosphere in the event of ion source component failure. To assure no effect on existing beam geometry, the valve thickness was held to 1 1/8 in. The valve gate consists of two disks separated by a short length of bellows. One disk, moving with the expansion and contraction of the bellows, contains the gasket in its outer face. The other disk contains a leak path from its edge to the interior of the bellows. The shaft is welded to the disk containing the leak path and exposes the leak path, through its hollow center, to the exterior of the valve housing. Evacuation of the bellows through the center of the shaft permits linear motion of the valve, by manual push or pull, to closed or open position. Letup of the bellows' interior to atmosphere holds the valve gate in the position it was placed manually.