Abstract: The method relates to the manufacture of a piston. This piston comprises a head and a stem extending transversely with respect to the head. A profiled element in bar form is first taken, the profile of which envelops that of the piston. This profiled element is cut up into slices, the width of each slice being at least equal to the maximum diameter of the piston, and the material of the profiled element slice which extends relatively beyond the desired profile for the piston is removed by machining. The method is particularly useful for manufacturing remote-controlled actuators for valves.

Abstract: The butterfly valve comprises a valve body traversed by a passageway and a closure element or butterfly valve disk placed transversely with respect to the passageway. An annular bearing surface of the valve disk is intended to bear on a valve seat placed within the passageway. The valve body is constituted by an annular member provided with a chimney in which an operating shaft is mounted. The annular member is supported in leak-tight manner by a bearing ring having a greater thickness in the radial direction than the wall of the annular member. The bearing ring is inserted between the two end portions of the piping system and forms part of the valve body under operational conditions.

Abstract: A butterfly valve disk is rotatably mounted within a passageway formed in the valve body and an annular seal fitted in the valve body projects within the passageway. A peripheral annular bearing surface formed on the valve disk is applied against the annular seal in the closed position. The valve disk carries a stop which is brought to bear on an internal surface of the valve in order to prevent rotational displacement of the valve disk beyond its normal position of closure.

Abstract: The antifriction device for the control shaft of a flow-regulating valve comprises a hollow body and a closure member rotatably mounted within the hollow body. An annular flange is formed on the control shaft at the level of at least one of the packing gland seals and applied against an annular shoulder of the valve body which surrounds the control shaft, a washer formed of material which is capable of creep deformation being interposed between the flange and the shoulder. A peripheral groove is formed in the shaft opposite to the washer and receives the washer material in the event of creep flow.

Abstract: A hollow valve body having two hubs for connection to a piping system and containing a spherical plug or ball is constituted by two shells cut from pipe sections. Each shell is shaped so as to form a flared-out portion in a spherical zone, the edge of which is provided with a semicircular notch. A sleeve having a recess at the inner end so as to form a valve seat is welded in position within one of the hub connections. The ball is enclosed between the two shells which are joined together by welding. A second sleeve also provided at the inner end with a valve seat is welded in position within the other hub connection. A stuffing-box is engaged on the ball-operating rod and welded to the orifice formed by the two oppositely-facing semicircular notches.

Abstract: An instantaneous signal applied to the inlet of the timing device is passed through a restrictor into a capacitance and the resultant rising pressure is compared with an adjustable-level reference pressure signal which defines the timing period. When the capacitance pressure exceeds the reference signal value, a comparison signal initiates the release of an obturator. The reference pressure propagates to the outlet of the device and produces the time-delay signal.

Abstract: The transition module is intended to be assembled with at least three action modules constituting a sequencer and comprises an elementary logical gate having two inputs and one output, two inputs for receiving the output signals of two predetermined action modules and directing the signals to the inputs of the logical gate, one output for directing the output of the logical gate towards a predetermined input of the third action module and a Y-duct for directly connecting the output of the third action module to a predetermined input of each of the first two action modules.

Abstract: A butterfly valve designed primarily for piping systems in which corrosive fluids are circulated at high temperature comprises a pivotally mounted disc having a convex annular edge portion associated with an annular seal which projects within the valve passage. The seal is formed by a specially shaped removable metallic ring coated with plastic material and having a flared cylindrical mouthpiece which is applied in fluid-tight contact with the edge portion of the valve disc and held in position within the valve passage by a retaining ring.

Abstract: The comparator for signals which are coded in a given number system and represented by a fluid pressure comprises a first and a second rigid block pierced by transverse ducts which are arranged in a row and to which is applied a fluid pressure representing respectively a first and a second input signal, at least one elastic membrane which separates the two blocks, a first and a second discharge duct pierced in the second block on each side of the transverse ducts, means actuated by the pressure representing the second signal so as to deform the elastic membrane and to permit propagation of said pressure in the direction of the two output ducts, and means actuated by the pressure representing the first signal in order to deform the elastic membrane and to prevent propagation of the pressure representing the second signal beyond the duct corresponding to the first signal.