A gas spring accumulator comprising:a housing (2, 3) provided with an inlet (20); anda flexible diaphragm (4) dividing the interior of the housing into a working chamber (7) which is exposed to system pressure via the inlet, and a gas chamber (6); characterised in that the housing includes a diaphragm element (4) having one side exposed to system pressure via the inlet (20) and an opposite side exposed to a further chamber (13), a first non-return valve (17) arranged to admit atmospheric gas into the further chamber (13), and a second non-return valve (29) arranged to admit gas from the further chamber (13) into the gas chamber (6).

An apparatus for determining the position of a movable separation element which is arranged within an accumulator as a separator between a gas space and a fluid space, wherein the determination apparatus comprises at least one pressure sensor for the detection of pressure data, at least one ultrasonic sensor for the detection of ultrasonic data and at least one calculation unit for the evaluation of the data with the aid of which determination apparatus the position of the separation element can be determined.

A rolling assembly, including at least one roll pair with two cooperating rolls and a safety device. The safety device includes a hydraulic accumulator and a measuring device. The hydraulic accumulator includes an accumulator with a first and second accumulator chamber. A hydraulic fluid is disposed within the first accumulator chamber. A compressible gas is disposed within the second accumulator chamber. The hydraulic accumulator includes a moveably arranged separating member separating the first accumulator chamber from the second accumulator chamber. The roll pair has a working position and a safety position. A radial distance between the rolls is larger in the safety position than in the working position. The hydraulic accumulator is configured to move the roll pair from the working position to the safety position. The measuring device is configured to continuously detect a position of the separating member within the hydraulic accumulator.

A rolling assembly, including at least one roll pair with two cooperating rolls and a safety device. The safety device includes a hydraulic accumulator and a measuring device. The hydraulic accumulator includes an accumulator with a first and second accumulator chamber. A hydraulic fluid is disposed within the first accumulator chamber. A compressible gas is disposed within the second accumulator chamber. The hydraulic accumulator includes a moveably arranged separating member separating the first accumulator chamber from the second accumulator chamber. The roll pair has a working position and a safety position. A radial distance between the rolls is larger in the safety position than in the working position. The hydraulic accumulator is configured to move the roll pair from the working position to the safety position. The measuring device is configured to continuously detect a position of the separating member within the hydraulic accumulator.

A fluid control system for controlling flow of a process fluid can include an actuator and an energy storage system. The actuator can be configured to actuate a valve to control the flow of the process fluid and the energy storage system can drive the actuator. The energy storage system can include an accumulator in fluid communication with the actuator and a manual pump configured to charge the accumulator.