| 摘要 |
<p>A fluid flow safety device comprises a body having an inlet end for connection to a fluid supply and an inlet passageway (8, 48, 103) which leads to a selective fluid flow sensor chamber (9, 49, 115) having a sealing means (10, 50) which encircles the outlet orifice (11, 51) of smaller cross section than that of the sensor chamber, said outlet orifice leading from the sensor chamber into a pressure chamber (12, 52) within the body leading to an outlet. Between the inlet end of the sensor chamber and the sealing means is a tapered section (13, 117), wherein the bore of the sensor chamber decreases in diameter as it nears the sealing means. A sensor chamber shield (120) may encircle the sensor chamber by forming , defining and separating the internal length of the sensor chamber passageway from that of the inlet or any other passageway. A ball (16, 56, 119) in the sensor chamber moves between the inlet passageway end of the sensor chamber and the outlet orifice, to form a seal with the sealing means when flow through the sensor is above a predetermined value. Within the pressure chamber is a movable piston (20, 60, 131) in sealing contact with it to increase or decrease the volume of the pressure chamber. Movement of the movable piston form a rest position fully towards the sensor chamber will deny a seal to made between the ball and the sealing means. The movable piston may be a primary valve mechanism which forms a seal between the inlet and outlet passagways. The movable piston may include an indicator mark visible only when the pressure in the pressure chamber is avove a predetermined value. Embodiments for LP gas include separate use of sensor chamber or movable piston with or without primary valve.</p> |
