Abstract: A multistage vacuum pump is achieved by utilizing a single piston and cylinder assembly having opposite end portions with substantially equal diameters and an enlarged diameter central portion. One end of the cylinder is closed by a valve and a first stage pumping chamber is defined between the valve and the piston. The enlarged diameter portion of the piston has an axial extent less than the axial extent of the enlarged diameter portion of the cylinder to define second and third stage pumping chambers on opposite sides of the enlarged diameter portion of the piston. The three pumping chambers are interconnected by passage means to an inlet and outlet to provide a sequential reduction in pressure. A single drive unit may be connected to a plurality of pumping units for reciprocating the piston in each pumping unit.

Abstract: A multistage vacuum pump is achieved by utilizing a single piston and cylinder assembly having opposite end portions with substantially equal diameters and an enlarged diameter central portion. One end of the cylinder is closed by a valve and a first stage pumping chamber is defined between the valve and the piston. The enlarged diameter portion of the piston has an axial extent less than the axial extent of the enlarged diameter portion of the cylinder to define second and third stage pumping chambers on opposite sides of the enlarged diameter portion of the piston. The three pumping chambers are interconnected by passage means to an inlet and outlet to provide a sequential reduction in pressure. A single drive unit may be connected to a plurality of pumping units for reciprocating the piston in each pumping unit.

Abstract: A valve open-close indicating apparatus comprises a cylindrical housing having two opposite ends in the axial direction thereof, a sleeve arranged in the housing for axial reciprocation between the opposite ends of the housing, and a cylindrical elastic member for urging the sleeve from both outer sides with respect to the axial direction so that the sleeve is normally situated in an intermediate position between the opposite ends. When a piston moves toward one end of the housing to open a valve, the sleeve is pressed toward the one end against the urging force of the cylindrical elastic member, and the indicating apparatus indicates "open." When the piston moves toward the other end to close the valve, the sleeve is pressed toward the other end against the urging force, and the indicating apparatus indicates "closed.

Abstract: A valve operating mechanism produces a rotating force for causing a valve body of the valve to shift relative to a valve seat thereof, so that the valve is opened and closed. A piston of the mechanism produces a rectilinear reciprocating force. A screw member is supported moveably along the rectilinear line and unrotatably in the housing and includes a pair of pawls helically projecting along the rectilinear line and a helical interval space defined between the helical pawls. A pivot is inserted into the helical interval space. A cylindrical rotating member is supported rotatably and unmoveably along the rectilinear line in the housing so as to surround the screw member. When the screw member receives the rectilinear reciprocating force to perform the reciprocating motion along the rectilinear line, the pivot is urged to rotate along the helical interval space in the rectilinearly unmoved state, and the cylindrical rotating member can rotate with the pivot.

Abstract: An vacuum evaporating apparatus for depositing thin films on a substrate comprises a vacuum tank, a hot-wall furnace for heating and evaporating a material to be evaporated, an auxiliary vacuuming means connected to the vacuum tank through a gate valve, a substrate exchanging mechanism for an evaporated substrate with a new substrate through the auxiliary vacuuming device, and a substrate transferring unit generally of a turn table located to be rotatable above the hot-wall furnace. The hot-wall furnaces are disposed in standing state in the vacuum tank, each of hot-wall furnaces being provided with a plurality of crucibles coaxial in a vertical direction in which the evaporation source materials are accommodated, heaters independently provided for the respective crucibles, and thermocouples connected to the respective heaters to independently control the temperatures of the respective crucibles.