A method of controlling the injection of hydraulic fluid into a high pressure diaphragm compressor having a hydraulic system, the method including: measuring a representation of pressure in a high-pressure part of the hydraulic system of the diaphragm compressor, and maintaining a desired pressure in the high-pressure part of the hydraulic system by adding hydraulic fluid to the high-pressure part of the hydraulic system under the control of a controller on the basis of the measuring of pressure.

A pressure sensor having a housing connected to a compressor head, the housing including a piston movably mounted in a cylinder, the cylinder is fluidly connected to a high-pressure part of a hydraulic system of the compressor, where the piston is adapted to be moved in a first direction away from the compressor head by the pressure of the hydraulic fluid in the high-pressure part, thereby moving a displacement member which is movably attached to the housing by one or more flexible suspensions, and the piston is adapted to be moved in a second direction towards the compressor head by the flexible suspension via the displacement member.

A high-pressure compressor having a hydraulic system and a gas chamber, where the hydraulic system includes a reservoir, connected to a hydraulic fluid chamber by a hydraulic flow path and a pump assembly positioned in the hydraulic flow path, and the compressor furthermore includes a control element controlling the flow of hydraulic fluid in the hydraulic flow path and thereby the pressure in the hydraulic fluid chamber, where the control element and the pump assembly is configured for controlling the pressure of hydraulic fluid in the hydraulic fluid chamber when the compressor is not in operation.

A tire pressure gauge includes a first tube having a first end secured to a connector; a joining member having a first end secured to a second end of the first tube; a check valve in the joining member and including and air outlet and an air inlet configured to be in fluid communication between the first tube and the air outlet; a spring biased pressure relief device projecting out of the joining member; a second tube threadedly secured to a second end of the joining member; a plunger in a first end of the second tube; a compression spring in the second tube and biased between the plunger and a second end of the second tube; and a rod-shaped measuring device through the compression spring, the measuring device having a first end secured to the plunger and a second end extending out of the second tube.

A pressure detection device is mounted within an actuator housing between a piston rod and the housing, to receive fluid leaked past a seal, via a bore in the housing. The pressure detection device is configured to provide an output indicative of the pressure or flow of the leaked fluid in the bore. Thus, the leaked fluid diverted via the bore operates the pressure detection device to provide an output indicative of leakage.

A leakage detection device for detecting water leakage in a water pipe of a water system after a stop valve of the water system is closed. The leakage detection device may be part of a stop valve, and may include an interior chamber connectable to the water pipe in such a way so as to receive a stagnation volume of the water when the water flow through the water pipe is stopped by the stop valve. An actuation element provides a force acting on a diaphragm or a piston in the direction of the first interior chamber and against or into the stagnation volume of water. If water leakage is present in the water pipe, the diaphragm or piston will move under the applied force to compensate for the leakage in the water pipe. A sensor unit may detect water leakage in the water pipe based on the movement.

A miniature wireless pressure sensor has an inductor and a capacitor. The inductor and the capacitor form a L-C resonator with a resonate frequency. The inductor's inductance is affected by a slidable electro-magnetic element. When an outside pressure is applied onto the element, it causes the element to move and such movement changes the inductance of the inductor. Because of that, the resonate frequency is changed. Therefore, the change in resonate frequency indicates a change in the outside pressure. The L-C resonator is calibrated to correlate with the outside pressure. Such a miniature wireless pressure sensor facilitates the monitoring of physiological pressure in different part of human body such as eyes and cranium.

An apparatus for measuring pressure of fluid in a shunt includes a distensible member arranged adjacent to a graduated scale. The shunt includes a shunt valve and the apparatus is attachable to, or incorporated into the shunt at a location either at the shunt valve or upstream of the shunt valve. Both the distensible member and the scale include radiopaque markers. The fluid in the shunt acts directly on the distensible member and the distensible member is distensible in the direction of the scale.

A microelectromechanical system (MEMS) ambient pressure and acoustic sensor including an enclosure having an enclosure wall that defines an interior chamber and an acoustic input opening to the interior chamber, a moving structure positioned within the interior chamber and being acoustically coupled to the acoustic input opening. The moving structure having an acoustic sensing portion that is movable in response to an acoustic pressure input and an ambient pressure sensing portion that is movable in response to an ambient pressure input. The sensor further including a circuit electrically coupled to the moving structure and that is operable to determine an acoustic output and an ambient pressure output based on a movement of the moving structure.

A pressure element for monitoring a fluid being applied to the pressure element, wherein the pressure element is configured to close an electrical circuit, as a result of a change in pressure which the fluid exerts on the pressure element, independently of an absolute value of the pressure, where the fluid preferably flows through a pipeline.