Abstract: A valve body 3 is provided at its one side with a part for receiving an operation tool which turns a valve spindle, the valve body further provided at the other side with a part for mounting a connection tool 8 by which an external piping is attached and detached, and the valve body 3 moreover provided at the middle with a part 33 having a non-round cross section and a part 34 concaved from the outside surface of the part 33. A support member 4 consists of an engaging section 43 which engages with the part 33 to restrict or prevent the valve body 3 from turning and shifting in position, and an engaging section 44 which engages with the part 34 to restrict or prevent the valve body 3 from axially shifting in position.

Abstract: A valve body 3 is provided at its one side with a part for receiving an operation tool which turns a valve spindle, the valve body further provided at the other side with a part for mounting a connection tool 8 by which an external piping is attached and detached, and the valve body 3 moreover provided at the middle with a part 33 having a non-round cross section and a part 34 concaved from the outside surface of the part 33. A support member 4 consists of an engaging section 43 which engages with the part 33 to restrict or prevent the valve body 3 from turning and shifting in position, and an engaging section 44 which engages with the part 34 to restrict or prevent the valve body 3 from axially shifting in position.

Abstract: A valve spindle is provided with a screw thread part which meshes with a valve body to move the valve spindle forwards and backwards. Provided between a rotation driving member and the valve spindle is an interlocking part which transmits a force of rotation of the driving member to the valve spindle and allows the valve spindle's forward and backward movement following its rotation. A bring-back preventing part is provided at a location continuous with the interlocking part to prevent movement of the valve spindle in response to rotation of the driving member in the direction of opening the valve on the basis of exciting pulses excessively supplied to the stepping motor during a valve closing operation.