Abstract: The invention relates to the automatic reloading of the gas space of a hydropneumatic accumulator. A means (20) for readjusting the load of the gas space (13) comprising a pressurized gas source (22) connected via an air system (24) to a loading valve (17) and a reinjection valve (26) controlled by a unit (27) for calculating a cycle for reinjecting gas into the gas space.

Abstract: Testing the reliability of flexible separators arranged under conditions enabling the cycling rate of testing to be accelerated. According to the invention, two separators are enclosed in two rigid chambers, each defining a liquid capacity and a gas capacity. The two gas capacities communicate with each other, and each of the liquid capacities communicates with means for causing the volume of each of them to vary in alternation.

Abstract: Testing the reliability of flexible separators arranged under conditions enabling the cycling rate of testing to be accelerated. According to the invention, two separators are enclosed in two rigid chambers, each defining a liquid capacity and a gas capacity. The two gas capacities communicate with each other, and each of the liquid capacities communicates with means for causing the volume of each of them to vary in alternation.

Abstract: The invention concerns a pressure tank comprising a rigid casing having opposite first and second orifices, and an elastically deformable separator extending inside the casing between the two orifices and subdividing the inside volume of the casing into variable-volume first and second compartments. The second compartment communicates with a hydraulic circuit via the second orifice. The first compartment is filled with elastically deformable solid elements, and the resulting assembly behaves like a spring. In the non-compressed state, the overall volume of the elastically deformable solid elements is substantially equal to the volume of the first compartment when the separator is at rest.

Abstract: A pressure vessel contains a flexible separator comprising three layers, an outer layer, an inner layer and an intermediate layer which is at least partly impermeable to gases. The intermediate layer comprises a metal film. A particular application of the pressure vessel is to braking circuits.

Abstract: A pressure vessel comprises an enclosure in which are a liquid orifice and a gas orifice spaced from the liquid orifice. A separator divides the enclosure into two variable volume chambers. One of these is a liquid chamber communicating with the liquid orifice and the other is a gas chamber communicating with the gas orifice. The separator has a transverse wall spaced from the gas and liquid orifices and movable inside the enclosure. There is an orifice in the enclosure communicating with the gas chamber through which there is passed into the gas chamber a sensor which is responsive at one end to the presence of a liquid. In a neutral position of this transverse wall the responsive end of the sensor is nearer the transverse wall than it is to the orifice in the enclosure through which it passes into the gas chamber. The sensor preferably comprises an optical probe.

Abstract: An elastomeric bladder for dividing a pressure vessel into two chambers is formed in one piece and carries integrally at least one rigid element (18 or 19). A tubular blank bladder 10A of raw elastomer is shaped in a mould by fluid pressure applied to the interior of the blank while the rigid elements 18, 19 are clamped against the ends E1, E2 of the bladder valve and a vulcanization is performed whereby the rigid elements 18, 19 are bonded to the bladder.