| 摘要 |
A pneumatically controlled needle valve including a cylindrical body intended to be mounted in a bore of a device, two annular sealing surfaces delimiting a chamber connected to a compressed-air supply device, a first compartment arranged inside the body communicatively with the chamber, a second compartment, a piston separating the first and second compartments, a rod having the piston secured thereto, the rod protruding axially from the body, a needle disposed on the rod intended, depending on a position of the needle, to bear or not to bear against a seat of the bore, at least one spring disposed in the second compartment, the spring acting on the rod in a direction for closing the valve by pressing the needle onto the seat, while air under pressure from the compressed air supply device acts on the piston in the opposite direction, the rod passing with sealing through a front end of the body, and a plug for closing a rear end of the body, the plug being connected to the body in such a way as to be prevented from a translational movement but free to rotate thereon, the plug being externally threaded to be screwed into a lapping of the bore. The valve comprises a cylindrical body, for mounting in a bore of the device to be fitted. Two annular sealing surfaces define a chamber which is connected to a compressed air supply device and which communicates with a first chamber. Said first chamber is provided inside the body and separated from a second chamber by a piston. The piston is an integral par of a rod which extends axially beyond the body and which is fitted with a needle valve. The second chamber contains at least one spring that acts on the rod in the valve closing direction, while the pressurized air acts on the piston in the opposite direction. The rear end of the body is closed by means of an end cap which is connected to the body such that cannot be displaced, but is free to rotate on said body. The aforementioned end cap is externally to the body such that it cannot be displaced, but is free to rotate on said body. The aforementioned end cap is externally threaded so that is can be screwed into an internal screw thread in the bore. The valve is suitable for painting installations.
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