A pressure-limiting valve includes a housing and a pressure adjustment device provided therein. The pressure-limiting valve further includes a valve seat arranged in the housing and configured to be closed by a spring-loaded closing element of the pressure adjustment device. The housing is composed of cast iron having spherical graphite. The housing is surface-hardened at least in a region of the valve seat.

The present application relates to a switching valve, a switching hydraulic system, and a crane, in which the switching valve having an oil inlet and an oil outlet comprises at least two pairs of valve oil ports, a pair of cartridge valves provided between each pair of valve oil ports, and the oil inlet and the oil outlet are controlled such that the oil inlet and the oil outlet are capable of shifting between communications with the at least two pairs of valve oil ports. The switching valve switches on and off communication between the oil inlet and the oil outlet and the at least two pairs of valve oil ports by controlling opening or closing of the cartridge valves.

A backflow prevention device including a tank inside of and moveable relative to a housing. A cap coupled to the housing and including inlet and outlet chambers fluidly connected through an inlet, the outlet chamber communicating with the tank. A shell is connected to the cap and includes a shell inlet chamber, which communicates with a first outlet hole of the inlet chamber, and a second outlet hole, which communicates with the tank. An inlet sealing member opens/closes the inlet to fluidly connect/disconnect the inlet chamber and the outlet chamber; and an outlet hole sealing member is moveable with the tank to open/close the second outlet hole. Closing the second outlet hole prevents water from flowing through the second outlet hole and switches the inlet from open to closed. Opening the second outlet hole allows water to flow through the second outlet hole and switches the inlet to open.

A relief valve assembly includes a housing assembly defining a chamber therein. The relief valve assembly includes a piston. The piston may be at least partially disposed within the chamber. The relief valve assembly includes a pilot inlet. The pilot inlet may be configured to provide a pilot pressure proximate a second end of the chamber. The relief valve assembly includes an overpressure inlet sealed from a first end of the chamber by the piston. The overpressure inlet may be configured to provide an inlet pressure which may actuate the piston when the inlet pressure exceeds the pilot pressure.

A vent valve comprises a valve housing defining a vent port and a valve member mounted within the housing so as to define a fluid system chamber and an activation chamber with the housing. The valve member is biased towards a closed position, in which fluid communication between the fluid system chamber and the vent port is prevented, by fluid pressure within the fluid system chamber acting on the valve member. The valve member is biased towards an open position, in which there is fluid communication between the fluid system chamber and the vent port, by fluid pressure within the activation chamber acting on the valve member. The vent valve further comprises a pressure limiting arrangement associated with the activation chamber to limit pressure therein to a predetermined pressure value.

Pressure volume regulator (20) for control of supply and pressure of barrier fluid for pumps and compressors subsea, comprising an inlet (18) for barrier fluid at an inlet pressure, a first outlet (19) and a second outlet (15), the inlet pressure is higher than the first outlet pressure that is higher than the second outlet pressure. The pressure volume regulator is distinctive in that the inlet and the second outlet are interlocked between a movable longitudinal interlock member (5) with valve elements operatively arranged at either end, the length of the interlock member plus said valve elements is shorter than the distance between an open-close valve mechanism of the inlet and an open-close valve mechanism of the second outlet.

Flow through pressure sensors for use in fluid chromatography systems include a planar device formed from diffusion bonding of a plurality of metallic sheets and at least one sensing element. The planar device has a top surface, a bottom surface and a flow through channel. A diaphragm formed from a portion of one of the top or bottom surfaces is located adjacent to a sensing region of the flow through channel and is attached to the sensing element. The diaphragm is sized to deflect a distance in response to fluid pressure in the sensing region, which has an internal volume of less than about 25 microliters. The diaphragm and attached sensing element form a pressure sensor that measures strain or deflection of the diaphragm to calculate a pressure within the sensing region.

A system for regulating pressure in a fluid supply pipe, including a valve operated by a double acting piston cylinder and in which the chamber of the cylinder, the pressure of which acts on the piston to move the rod in the direction for closing the valve, communicates with the transmission mechanism for transmitting the instantaneous hydraulic pressure at a point of the pipe. The chamber of the cylinder, the pressure of which acts on the piston to move the rod in the direction for opening the valve, is connected to an energy accumulator accumulating energy in the form of pressurized gas at a predetermined pressure P0, which can be regulated.

The present disclosure relates to a hydraulic system with at least two main control valves and with a hydraulic pilot control system for actuating the main control valves, wherein the hydraulic pilot control system and/or the main control valves are constructed such that the at least two main control valves open one after the other.

A safety valve control system may include a remotely operable control assembly, a first transducer, a valve assembly, and a compressor assembly in communication with the control assembly. The control assembly is operable to actuate the pump and valve assemblies to supply fluid to actuate the safety valve into open and closed positions, in response to one or more signals received from the first transducer. A method of operation may include maintaining the safety valve in an open or closed position while sensing a physical property with the control system; communicating a signal corresponding to the sensed physical property to the control system; and automatically closing or opening the safety valve in response to a comparison of the sensed physical property to a pre-set condition.