Jet non=return valve has waisted section in circular passage between valve housing

摘要

A jet non-return valve incorporated in gas or fluid pipes has a jet ring which is held centred within a valve housing by projections from the housing, which also co-axially surround a jet insert. A circular valve is inserted in the ring with its end facing the oncoming flow. The valve slides back and forth. In the open position it to provides flow access to circular orifices respectively between itself, the housing and the insert. In the closed position the valve rests on a seat formed on one side by the housing and on the other by the jet insert, closing the narrowing circular passage between the housing and jet insert. Seen in the valve direction of flow (14), the circular passage (10) between the housing (2) and jet insert (4) has a waist (12) near the valve seat (9) and circular passage constriction. The waist widens after the valve seat at an angle of 30 to 40 degrees into the flow passages (11) between the valve housing and jet ring (3) and between the jet ring and the jet insert (4).