A fluid leakage detection system includes: a measurement unit configured to detect leakage of working oil in a hydraulic cylinder; and a controller configured to acquire a measurement result from the measurement unit, wherein the controller diagnoses that a battery depletion has been caused in a battery in a case in which it is determined that a data from the measurement unit has not been acquired and it is determined that the battery of the measurement unit has been in a low-remaining-battery-level state, and the controller diagnoses that a communication abnormality has been caused in a first communication part of the measurement unit in a case in which it is determined that the data from the measurement unit has not been acquired and it is determined that the battery has not been in the low-remaining-battery-level state.

A failure detection apparatus for a hydraulic system, to a hydraulic, failure detection-capable system, and to a method of operating a failure detection apparatus. The failure detection apparatus comprises a monitoring and failure detection unit that receives first and second pressure values from first and second pressure sensors and comprises a failure detection unit that detects a failure of at least one hydraulically operated device when a 2-tuple of a plurality of 2-tuples is within a first and outside a second predetermined tolerance range of relative pressure values, and wherein the failure detection unit 260 detects a failure of the pump when a 2-tuple of the plurality of 2-tuples is outside the first predetermined tolerance range of relative pressure values.

A monitoring system (500) of an on/off type actuator device (1) for activating a valve for fluid pipelines is described, the actuator device (1) being configured to move a valve member of said valve between a first position and a second position. The actuator device (1) comprises at least one fluid cylinder (6) configured to control a linear movement of an actuator rod (8). The monitoring system (500) comprises a plurality of sensors mounted on the actuator device (1) and configured to detect a plurality of operating parameters of the actuator device, and an electronic processing and control unit (50). The electronic processing and control unit (50) is configured to impart a micro-movement to the valve member, to detect signals indicative of the values of said operating parameters during said micro-movement of the valve member, and as a function of said values of said detected operating parameters to estimate if said actuator device (1) is capable of applying a torque or force value sufficient to make said valve member perform the entire movement from the first position to the second position. The micro-movement is such as to constitute only the start of movement of the movable member of the valve, corresponding only to the overcoming of mechanical clearances and dissipative and deformation effects internal to the actuator (1), and furthermore is such as not to substantially involve any alteration in the flow of fluid controlled by the valve. In this way, it is possible to estimate the state of health of the actuator device (1) without causing variations in the flow of fluid through the aforesaid valve.

A valve drive device is provided, with a fluid-actuated valve drive (25) which includes a drive unit (23) which has a drive housing (27) which defines a housing interior (26) and in which a drive piston (28) of the drive member (24) is movably received and divides the housing interior (26) into two working chambers (29a, 29b), of which at least one can be subjected to fluid, with a force monitoring device (37) for monitoring the actuation force which is generated by fluid pressure and acts upon the drive piston (28), with a position monitoring device (60) for monitoring the position of the drive piston (28) and with an electronic control device (41) for controlling the valve drive (25) on the basis of the force and position data which is provided by the force monitoring device (37) and the position monitoring device (60).

A sensor unit for a fluidic cylinder having a base carrier on which a circumferential seal is formed, so that an interior of the fluidic cylinder is sealable, and having a position sensor for detecting a position of the piston, and having a pressure sensor for detecting a pressure in the interior.

Provided is a construction machine including a hydraulic system having a hydraulic pump, and a first hydraulic actuator and a second hydraulic actuator which are driven by hydraulic oil supplied from the hydraulic pump. The construction machine includes a first flow rate detector that detects a flow rate of drain hydraulic oil discharged from the first hydraulic actuator, a second flow rate detector that detects a flow rate of drain hydraulic oil discharged from the second hydraulic actuator, and an abnormality determination unit that determines abnormality of the first hydraulic actuator, based on a detection signal from the first flow rate detector, and determines abnormality of the second hydraulic actuator, based on a detection signal from the second flow rate detector. The first flow rate detector and the second flow rate detector each have a moving body.

A fluid leakage detection device includes: an annular member attached to a cylinder head, the annular member being configured such that a piston rod is inserted through the annular member; a passage formed in the annular member, the passage being configured such that a working fluid is guided to the passage from a gap between an outer circumference of the piston rod and an inner circumference of the cylinder head; and a detector configured to detect the working fluid guided through the passage, wherein the annular member includes a press-fitted portion, the press-fitted portion being configured to be press-fitted to an annular groove formed in the cylinder head.

Methods and apparatus for quantifying pneumatic volume usage via valve controllers are disclosed. An example apparatus includes a valve controller operatively couplable to a pneumatic actuator, the pneumatic actuator being operatively coupled to a control valve. In response to an input signal indicating that a flow control member of the control valve is to be moved in a specified direction, the valve controller commands a current-to-pressure (I/P) converter of the valve controller to pulse a relay valve of the valve controller between a closed position and an open position. The pulsing of the relay valve causes the pneumatic actuator to move the flow control member in the specified direction. The valve controller calculates a pneumatic volume usage associated with the moving of the flow control member in the specified direction. The pneumatic volume usage is based on the pulsing of the relay valve.

In a fluid circuit for an air cylinder connected to a switching valve provided with exhaust ports, a head-side pressure chamber is connected to the switching valve by a first pipe, and a rod-side pressure chamber is connected to the switching valve by a second pipe. A first restrictor is disposed at a connection point between the first pipe and the switching valve or in the vicinity of a first output port of the switching valve, and a second restrictor is disposed at a connection point between the second pipe and the switching valve or in the vicinity of a second output port of the switching valve.

A hydraulic tool is mountable to a prime mover. The hydraulic tool includes a bore-side hydraulic pressure sensor, a rod-side hydraulic pressure sensor, a control circuit, a wireless transmitter antenna providing a communication channel to a user interface, and a protective box assembly housing the bore-side hydraulic pressure sensor, the rod-side hydraulic pressure sensor, the control circuit, and the wireless transmitter antenna.