HIGHLY CLEAN AND HOT VALVE

摘要

Provided is a highly clean and hot valve, which can improve the general versatility as a valve apparatus for a using environment. A valve driving unit (30) and a valve casing (40) are connected to a bonnet (20) supporting a valve stem (12) slidably. A stem portion (34) has one end positioned in a circumferential wall (31) closed at its two ends by an upper cover (32) and a lower cover (33), and supports one end of the valve stem (12) with its other end extending through the lower cover (33). The stem portion (34) has its one end supported by a first bellows (35) and its other end supported by a second bellows (36) for closing an axial through hole (33a) of the lower cover (33) tightly. A first pipe (32a) is made to communicate with a first space (37) isolated by the first bellows (35), and a second pipe (31a) is made to communicate with a second space (38) isolated by the first bellows (35). The fluid quantities in the first and second spaces (37 and 38) are increased or decreased relative to each other, thereby to drive the stem portion (34) supported in a floating state by the first and second bellows (35 and 36).