| 摘要 |
An isolation valve assembly having a valve body (22) provided with an inlet (23) and an outlet (24), fluidly connected by a fluid passageway (25), and an isolation valve (26, 27) that is operable to selectively open or close the fluid passageway. A vent is fluidly connected to the fluid passageway and a vent valve (34) is operable to open and close fluid communication between the fluid passageway and the vent. The vent valve comprises a stem (36) with a sealing member (37) and is operable between an open position, in which the sealing member is disposed such that the fluid passageway and the vent are fluidly connected and a closed position in which the valve stem extends across the fluid passageway and the sealing member seals the vent from the flow passageway. |
