Presented herein are systems and methods that allow for adapting at least one dimension of an accumulator in a hydraulic system when faced with certain dimensional constraints and to vary the compliance or stiffness of an 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.

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.

A control system may receive sensor data indicative of respective fluid levels of two or more hydraulic accumulators configured to operate at respective target fluid levels within a hydraulic system. The control system may determine respective errors of the hydraulic accumulators based on the respective fluid levels and respective target fluid levels of the hydraulic accumulators. The respective errors may correspond to pressure errors, fluid volume errors, or other types of errors of the hydraulic accumulators. Responsive to determining the respective errors, the control system may determine that the error of a given hydraulic accumulator is greater than errors of the other hydraulic accumulators and provide instructions to control a hydraulic valve to supply fluid from a single pump of the hydraulic system to the given hydraulic accumulator

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.

A hydraulic pumping system can include an actuator including a piston rod that displaces in response to pressure in the actuator, a seal assembly that seals about the piston rod and is exposed to the pressure in the actuator, and another seal assembly that seals about the piston rod, is exposed to pressure in a well and includes multiple separate seal cartridges, each of the seal cartridges including a dynamic seal that slidingly and sealingly engages the piston rod. Another hydraulic pumping system can include an actuator including a piston rod that displaces in response to pressure in the actuator, a seal assembly that seals about the piston rod and is exposed to the pressure in the actuator, and another seal assembly that seals about the piston rod, is exposed to pressure in a well and includes a labyrinth ring comprising multiple ring layers.

A control system may receive sensor data indicative of respective fluid levels of two or more hydraulic accumulators configured to operate at respective target fluid levels within a hydraulic system. The control system may determine respective errors of the hydraulic accumulators based on the respective fluid levels and respective target fluid levels of the hydraulic accumulators. The respective errors may correspond to pressure errors, fluid volume errors, or other types of errors of the hydraulic accumulators. Responsive to determining the respective errors, the control system may determine that the error of a given hydraulic accumulator is greater than errors of the other hydraulic accumulators and provide instructions to control a hydraulic valve to supply fluid from a single pump of the hydraulic system to the given hydraulic accumulator.

A hydraulic drive system for driving a load includes a drive shaft; first and second hydraulic pumps driven by the drive shaft, and a control system that operates the hydraulic drive system in a plurality of modes including: a) a first mode where the second hydraulic pump pumps hydraulic fluid from a supply line to an accumulator; b) a second mode where the second hydraulic pump pumps hydraulic fluid from the accumulator to the supply line; c) a third mode where the second hydraulic pump pumps hydraulic fluid from the supply line to a reservoir; and d) a fourth mode where the second hydraulic pump pumps hydraulic fluid from the reservoir to the supply line. At least the second hydraulic pump is a variable displacement bidirectional pump.

A method includes detecting at least one position measurement of a separator piston of a pitch trim actuator. The method includes detecting at least one pressure measurement of an oil. The method includes detecting at least one temperature measurement of the oil. The method includes storing at least one position value based on the at least one position measurement of the separator piston, at least one pressure value based on the at least one pressure measurement of the oil and at least one temperature value based on the at least one temperature measurement of the oil. The method includes determining whether the pitch trim actuator requires servicing based on the at least one position value, the at least one pressure value, and the at least one temperature value.

A piston type hydro pneumatic accumulator with internal leak detection, having a gas chamber and a liquid chamber, the piston type hydro pneumatic accumulator comprising a cylindrical barrel, a floating piston, a gas end cover, a liquid end cover, a leakage detection construction having a first cylindrical channel reducing to a conical channel and further reducing to a second cylindrical channel, a floater device, the gas end cover and the liquid end cover hermetically disposed into the cylindrical barrel, a first pressure meter disposed so as to measure a pressure in the first cylindrical channel and a second pressure meter disposed so as to measure the pressure in the second cylindrical channel, the readings in the two pressure meters used for inferring a gas leakage or a liquid leakage. Also deployable a first pressure switch sensing a pressure P1 and a second pressure switch sensing a pressure P2, the output of the first pressure switch and the second pressure switch connected to a programmable logic controller, programmed so as to activate a liquid circuit for topping up of the liquid if P1>P2, activate a gas circuit for re-charging of gas if P1=P20, produce a visual and or an audio signal or a combination thereof, or initiate any other corrective action.