| 摘要 |
A valve assembly comprises a valve body having a hollow and a valve element longitudinally movable between first and second positions therein. The valve assembly has at least one inlet and at least one outlet in pressure communicating relation to the hollow. The valve element in its first position blocks pressure communication between the inlet and the outlet. In its second position, the valve element permits pressure communication between the inlet and the outlet. A pressure sensitive indicator is operatively associated with the valve element. The assembly provides pressure communication between the inlet and the indicator when the valve element is in one of its positions and blocks such pressure communication in the other position. The assembly may also include other inlets and outlets, and the high pressure inlets are preferably longer than the respective controlling seals. Thus the seals need not cross the inlets to control flow therethrough. The bypass valve assembly can be incorporated in a system for monitoring pressure within a fluid flow-line and selectively controlling fluid flow in that line and in a method for testing the controlling apparatus without interruption of flow in the line being monitored.
|
