| 摘要 |
<p>A fabricated ball valve (22) is positioned between the inlet (14) and the outlet (16) of a valve housing and includes a first tubular member (24) having sealing faces (26) on each end for seating on valve seats (18-20) and providing flow therethrough when the first tubular member (24) is aligned between the inlet (14) and the outlet (16). Second (28) and third (30) tubular axially aligned members have one end connected to the outside of the first member (24) and have sealing faces (34-38) on their other ends for seating on the valve seats (18-20). The second (28) and third (30) members block flow through the valve when the second (28) and third (30) members are aligned between the inlet (14) and outlet (16). Sealing means may be on either the valve seats (18-20) or on the movable seat ring connected to each of the other ends of the second (28) and third (30) tubular members. The seat rings (70-80) connected by a lost motion connection and include an outer seat (76-86) in their outer ends for seating on the valve seat (18-20) and an inner seat (72-88) between the seat rings (70-80) and the second (28) and third (30) members with the diameter of the inner seal (72-88) greater whereby pressure urges the outer seal (76-86) onto the valve seat (18-20). The housing may include a closure flange (91) on the side or the top that can be opened for repairing the valve. The valve housing may include a raised face (64) about the inlet and outlet for receiving a companion flange.</p> |
