Disclosed is an expansion tank having an internal cavity separated by a flexible diaphragm to form an upper pressurized gas portion and a lower pressurized fluid portion, and an indicator positioned at an upper part of the expansion tank in communication with the contents of the upper pressurized gas portion. The indicator is configured so as to display a first color if the operating conditions arc normal in the pressurized gas portion, and a second color if the amount of moisture detected in the pressurized gas portion greater than or equal to a predetermined amount. Further disclosed is a method for detecting whether there is an excessive amount of moisture in a pressurized gas portion of an expansion tank by allowing pressurized gas from the pressurized gas portion to come into contact with the indicator, and viewing the color displayed by the indicator. As such, the tank can be simply visually inspected to determine whether there is a potential failure in the tank.

The invention relates to a tensioning cylinder device, comprising a housing (2) and and at least partly longitudinally movable piston-rod unit (30, 34) arranged therein, and comprising a compensating element in the form of a bellows body (18) having bellows folds, which is longitudinally variable and has a media-carrying connection to a compressible medium accommodated in a medium chamber (12) in the housing (2).

A shell member 10 constituting an accumulator 100 including a cover member 30, a shell member 10 having a cylindrical portion 11, an opening portion 13 formed at one end of the cylindrical portion 11 and welded to the cover member 30, and a closed portion 12 formed at another end of the cylindrical portion 11, and an accumulation part 70 accommodated in the shell member 10. The cylindrical portion 11 includes an upper end portion 11a, and a protruding portion 11c having the opening portion 13. The protruding portion 11c is thicker than the upper end portion 11a.

A center biased actuator having an outer cylinder, a slave cylinder linearly transposed within the outer cylinder, a rod assembly with a piston linearly transposed within the slave cylinder and a rod extending from the outer cylinder, one or more first dynamic seals arranged to act on a sidewall of the rod to inhibit hydraulic fluid leaking from the outer cylinder, one or more second dynamic seals arranged to act on a sidewall of the slave cylinder or an inner surface of the outer cylinder to inhibit hydraulic fluid leaking from the outer cylinder, and a gas chamber comprising a sealed expandable chamber containing gas. The expandable chamber is arranged to act on hydraulic fluid within the center biased actuator to bias the center biased actuator to assume an intermediate condition which lies between a compressed condition and an extended condition.

An accumulator is provided, which is aimed at stabilization in mounting state of a damping member while diminishing the impact on a metal bellows. In an accumulator (100), a damping member (190) formed slidably at the inner circumferential surface of a pressure vessel (110) and suppressing the oscillation of a metal bellows (130) while keeping a gap between the metal bellows (130) and the inner circumferential surface of the pressure vessel (110) is mounted at at least one site of a plurality of annular valley parts of the metal bellows(130) including a plurality of annular crest parts and the plurality of annular valley parts alternately formed therein. In the damping member (190), a radially inward tip is fitted with the valley part, and a radially outward tip is longer than the crest part of the metal bellows radially and outwardly.

An expansion tank with an improved diaphragm seal includes a seal for the joint between the flexible diaphragm and either an optional. non-flexible diaphragm or the tank wall, the providing of a seal support that prevents collapse, delamination, or tearing of the 5 tank shell wall. The tank shell may be formed of two substantially hemispherical domes joined together, either directly or at the two ends of a substantially cylindrical section. One of the segments forming the shell of the expansion tank, further comprises an extension lip, extending inwardly of the tank and around the entire circumference of the inner surface of the shell wall, located substantially near the junction of two of the sections 10 forming the tank. This extension lip may be made from the same material as the tank wall, or may be part of a separate circumferential connector interconnecting two of the sections of the tank wall.

The invention relates to a method for producing pressure vessels, including pressure accumulators, such as hydraulic accumulators and parts thereof (24), characterized in that they are at least partially produced by means of a 3D printing method.

A fluid system includes a reservoir having a first reservoir chamber and a second reservoir chamber separated by a movable barrier, the first reservoir chamber being configured to contain a working fluid. The fluid system includes a piston housing defining an internal volume and a piston movable within the internal volume, the piston separating the internal volume into a first piston chamber and a second piston chamber, the second piston chamber being fluidly coupled to the second reservoir chamber. The fluid system includes a fluid supply configured to provide a control fluid to the first piston chamber.

Separator and hydraulic accumulator having such a separator. A separator, in particular for a hydraulic accumulator, such as a bellows accumulator, which is produced by a 3D printing process, consisting of one single diaphragm, which, when viewed in cross section, is deflected in an arcuate shape to form a multitude of bellows pleats at deflection points, which delimit the bellows pleats on the outside and the inside, and in that, to obtain an isotensoid or essentially isotensoid stress profile in the diaphragm, the notional extensions of the diaphragm surfaces adjacent to each deflection point form an acute angle with each other, at least in an initial state.

The present disclosure relates to a variable pressure vessel. The vessel includes a liquid chamber and a gas chamber and a moveable barrier therebetween. The vessel has a volume, a first stroke, and a second stroke. The liquid chamber and the gas chamber each have a variable volume that changes responsive to the first stroke and the second stroke. The gas chamber has an outer wall wherein at least a portion of the outer wall is thermally conductive and allows heat to transfer therethrough. Movement of the moveable barrier between the liquid chamber and the gas chamber causes the volume in the liquid chamber and the volume in the gas chamber to displace each other. The volume in the gas chamber plus the volume in the liquid chamber is generally constant and generally equals the volume in the variable pressure vessel.