SAFETY GAS VALVE CAPABLE TO ATTAIN A BLOCKING CONDITION WHEN SUBJECTED TO A FLOW IN EXCESS OF ITS NOMINAL WORKING CONDITIONS, INTERPOSED BETWEEN A SOURCE OF GAS UNDER PRESSURE AND THE DEVICE OR EQUIPMENT TO WHICH SAID SOURCE OF GAS IS BEING SUPPLIED

摘要

In a body, a first passage (6) is practiced within which houses a first piston (8) able to be selectively driven by the excess gas flow towards a blocking position and seal. The valve body has a second through-cut (17) arranged under water intersecting the seal seat (7) of the first frustoconical piston (8). Within this second cut sits a second piston (21), pressing the end (20) thereof down against the end (9) of the protrusion of the first piston seal seat. This second piston (21) has means by which it is possible to move the second piston in interference with the end (9) upstream of the first piston seal eliminating the relationship with said seal seat.

主权项

1. Safety gas valve capable to attain a blocking condition when subjected to a flow in excess of its nominal working conditions, interposed between a source of gas under pressure and the device or equipment to which said source of gas is being supplied, wherein a valve body has a first and a second end, having said valve body a first bore defining a first passage open at both ends thereof; this first end of the valve body with said first bore communicates with the gas source, whilst its opposite end connects with a coupling means or device linkable to the actual device to which the gas is being fed; within said first bore it is provided a seat, against which seats in a selectively sealing relationship one end of a first piston placed within said first bore, while the opposite end of this first piston is facing the gas stream coming from said gas source; between this sealing seat and the first mentioned piston it is placed a compression spring biasing the first piston towards said first end of the valve body, reacting this spring against a recess provided in said first piston; said first piston travels axially within said first passage from a position allowing the free passage of gas, to a blocking and sealing position in which it closes said first passage preventing the outlet of said fluid, wherein said valve includes a second bore performed in said valve body, substantially perpendicular to the axis of the first bore defining said second bore a passage intersecting and communicating with said first passage or bore immediately after the sealing seat of the first piston; within said second bore or second passage it is housed a second piston or plunger sliding axially within said second passage and biased by an elastic means, with its longitudinal axis intercepting the longitudinal axis of the first piston; this second piston has means accessible from outside said valve body capable to selectively displace said second piston or plunger at a meeting point of its longitudinal axis in interception with the axis of the first piston when said first piston is found in its sealing position in a sealing and blocking relationship, causing the axial displacement of the first piston away from the sealing connection, resetting the free gas passage, while the first piston is having an end thereof along its longitudinal axis in interception of said second piston, displacing said plunger upwards when said first piston is displaced in its sealing position, causing the blocking of the main passage and the corresponding axial displacement upwards of the second piston.