Abstract: A metal diaphragm type valve includes a valve seat holder supported from a rotatable valve stem, a metal diaphragm and a deflection limiter. The valve seat holder has a shaft extending upwardly through central openings in the diaphragm and the deflection limiter. A diaphragm support step having an annular flat surface joining an arcuate shoulder is provided around the shaft of the valve seat holder and the inner peripheral edge of the diaphragm rests on the flat surface. The deflection limiter has a flat bottom surface facing the top surface of the diaphragm and an arcuate surface extends radially outwardly from the flat bottom surface. The deflection limiter, diaphragm and valve seat holder are welded together by a weld extending through the flat bottom portion of the deflection limiter and the inner peripheral edge of the diaphragm to the flat surface on the seat holder, the weld forming an air-tight seal between the valve chamber and the passage for the shaft.

Abstract: A tightening tool comprises a head having a socket for a nut to fit in, a head support supporting the head rotatably about the axis of the socket, and a handle integral with the head support. A magnet is attached to each of the head and the head support. The head and the head support are joined together by a force of attraction permitting these portions to rotate relative to each other upon the torque of tightening up the nut reaching a proper value. When the head support is rotated by turning the handle by hand, the head moves with the head support to tighten the nut. After the nut tightening torque has reached the proper value, the head support merely rotates idly with the head and the nut remaining unrotated even if the handle is turned.

Abstract: An actuator comprises a valve case opened upward, a gas-driven actuator having a fixed portion provided on the valve case and fixed thereto and an operating portion movable upward and downward by a drive gas when the gas flows in or out, a valve stem extending upward from inside the valve case to above the case and having its upper end fixed to the operating portion of the actuator, and a valve element provided on the lower end of the valve stem. A valve case fluid seal bellows and an actuator gas seal bellows are connected between the valve stem and the actuator fixed portion and between the actuator fixed portion and operating portion, respectively. A vacuum is contained in a closed space formed by the valve stem, fluid seal bellows, actuator fixed portion, gas seal bellows and actuator operating portion.

Abstract: A control valve comprises a valve body having a fluid channel and a valve seat; a valve operating part; a valve stem supporting member having its upper end fixed to the valve operating part and its lower end fixed to the valve body; a valve stem penetrating the valve stem supporting member and having its upper end part connected to the valve operating part and its lower end part entering the valve body, the valve stem being movable upward or downward by the valve operating part; and a valve element attached to the lower end of the valve stem. The valve element is moved upward or downward by moving the valve stem upward or downward, the valve element being brought into contact with and seated in the valve seat to close a fluid channel as it is moved downward, the valve element being detached from the valve seat to open the fluid channel as it is moved upward.