A fluid tank includes polymeric liner comprising an upper wall and a lower wall. The upper wall and the lower wall define a cavity therebetween. A weld joint joins the upper and lower walls together. A method for assembling a fluid tank includes overlapping surfaces of an upper wall and a lower wall to form a liner defining a cavity. The method includes joining the surface of the upper wall and the surface of the lower wall together by welding to form a weld joint between the upper wall and the lower wall. The method can include cooling the weld joint to control warpage of the liner at the weld joint.

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 are 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.

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 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 energy recovery system may include a compressor, an air tank, and a motor. The compressor may have a swashplate member and one or more piston and cylinder assemblies aligned with a compressor axis. The swashplate member may be able to tilt relative to the compressor axis between a no-compression position and a maximum compression position in which each piston can move within its respective cylinder between a top dead center position and a bottom dead center position. The swashplate member may be arranged to be coupled to a shaft so that the compressor axis is substantially aligned with a shaft axis and so that the swashplate member is able to rotate in tandem with the shaft, and also may be able to tilt relative to the compressor axis between no-, maximum-, and intermediate-compression positions. In the no-compression position, each piston may be located at the top dead center position.

The disclosure relates to an hydraulic accumulator, in particular a diaphragm accumulator, having an accumulator housing and a separating element disposed therein, which separates two media spaces from each other, wherein a weld seam is formed by a laser or electron beam welding process without any filler materials, in that at least a part of the wall parts delimiting the transition point are melted to form the weld seam, which closes off the transition point towards the surroundings, in a manner that is free of protrusions with respect to an outer circumferential surface of a connection element.

The disclosure relates to an hydraulic accumulator, in particular a diaphragm accumulator, having an accumulator housing and a separating element disposed therein, which separates two media spaces from each other, wherein a weld seam is formed by a laser or electron beam welding process without any filler materials, in that at least a part of the wall parts delimiting the transition point are melted to form the weld seam, which closes off the transition point towards the surroundings, in a manner that is free of protrusions with respect to an outer circumferential surface of a connection element.