A valve for preventing water hammer includes a speed reduction device for reducing a speed at which the valve may be closed. A method of preventing water hammer includes closing a valve at a fire hydrant after extracting water from the fire hydrant, in which the valve comprising a speed reduction device that increases an amount of time needed for closing the valve, and operating the valve to close the valve comprises operating the speed reduction device.

A check valve comprises a valve housing defining a pair of valve openings, a pair of mounting posts arranged on opposed sides of the valve housing, a hinge pin mounted between said mounting posts, a pair of flapper elements pivotably mounted to the one or more hinge pins for rotation relative to the housing between an open position in which they permit fluid flow through the respective valve openings and a closed position in which they prevent fluid flow through the valve openings. A pair of elastically deformable leaf spring stop elements, each of which comprise respective end portions that are mounted to, and extend upwardly from, said mounting posts and a stop portion arching upwardly from, and extending between said end portions, such that each flapper element will engage a respective surface of said stop portion when in the open position.

Certain embodiments provide a cover mounted on top of a manifold, the cover comprising an exhaust opening and an inner surface forming a space between the inner surface of the cover and an outer surface of the manifold, wherein the space is configured to receive pressurized gas at an inlet positioned on a first side of a valve. The valve is coupled to the outer surface of the manifold and positioned within the space. The exhaust opening is positioned on a second side of the valve opposite the first side of the valve such that pressurized gas circulates from the inlet around the valve and exits through the exhaust opening.

Certain embodiments provide a cover mounted on top of a manifold, the cover comprising an exhaust opening and an inner surface forming a space between the inner surface of the cover and an outer surface of the manifold, wherein the space is configured to receive pressurized gas at an inlet positioned on a first side of a valve. The valve is coupled to the outer surface of the manifold and positioned within the space. The exhaust opening is positioned on a second side of the valve opposite the first side of the valve such that pressurized gas circulates from the inlet around the valve and exits through the exhaust opening.

A spool valve V1 includes a valve element 11 and a cylinder 12 having a bore 12a which accommodates the valve element 11 to be movable in an axial direction. In this spool valve V1, when the valve element 11 in an initial position moves in the axial direction in relation to the cylinder 12, a supply valve port Vi formed between the valve element 11 and the cylinder 12 opens, whereby a working fluid is introduced from a hydraulic pressure source into a hydraulic chamber through the supply valve port Vi. A throttle portion O1 is provided in a fluid channel formed on the hydraulic chamber side of the supply valve port Vi. The throttle portion O1 is configured such that in a throttle valid region which extends from the initial position to a position where the amount of axial movement of the valve element 11 from the initial position becomes equal to a predetermined value, the area of the opening formed between the valve element 11 and the cylinder 12 is constant, and in a throttle invalid region where the amount of axial movement of the valve element 11 exceeds the predetermined value, the area of the opening increases. Thus, it becomes possible to restrain occurrence of oil impact within the hydraulic chamber to which the working fluid is supplied through the spool valve V1.

A spool valve V1 includes a valve element 11 and a cylinder 12 having a bore 12a which accommodates the valve element 11 to be movable in an axial direction. In this spool valve V1, when the valve element 11 in an initial position moves in the axial direction in relation to the cylinder 12, a supply valve port Vi formed between the valve element 11 and the cylinder 12 opens, whereby a working fluid is introduced from a hydraulic pressure source into a hydraulic chamber through the supply valve port Vi. A throttle portion O1 is provided in a fluid channel formed on the hydraulic chamber side of the supply valve port Vi. The throttle portion O1 is configured such that in a throttle valid region which extends from the initial position to a position where the amount of axial movement of the valve element 11 from the initial position becomes equal to a predetermined value, the area of the opening formed between the valve element 11 and the cylinder 12 is constant, and in a throttle invalid region where the amount of axial movement of the valve element 11 exceeds the predetermined value, the area of the opening increases. Thus, it becomes possible to restrain occurrence of oil impact within the hydraulic chamber to which the working fluid is supplied through the spool valve V1.

An automatic faucet includes a faucet body, an inner core assembly, and a sensor. The inner core assembly includes a valve core, a valve core seat, and a sleeve. The valve core is mounted on the valve core seat. The valve core seat has a cold water hole, a hot water hole, a mixed water hole, and a water outlet. The sleeve is mounted beneath the valve core seat, and has a cold water inlet and a hot water inlet. The sleeve further has a diversion passage communicating with the cold water inlet. The sensor is used to open or close the diversion passage. The sensor includes a sensing module, a solenoid valve, and a buffer rod.

A method for switching over a solenoid valve having a movable valve body between a first position and a second position, wherein the method comprises at least the following method steps: a) adjusting a switching current to a pre-energization current intensity, in which the valve body remains in the present position, for a first time interval, and b) adjusting the switching current to a first switchover current intensity, which introduces a switchover movement of the valve body, for a second time interval.

A method for switching over a solenoid valve having a movable valve body between a first position and a second position, wherein the method comprises at least the following method steps: a) adjusting a switching current to a pre-energization current intensity, in which the valve body remains in the present position, for a first time interval, and b) adjusting the switching current to a first switchover current intensity, which introduces a switchover movement of the valve body, for a second time interval.

A pressure relief valve includes a valve seat at the outlet, a valve body, and an air dashpot damper. In some embodiments, the valve body is configured to engage the valve seat and move along a central axis relative to the valve seat in response to a pressure at the outlet to regulate a flow of combustible gas through the outlet. In some embodiments, the air dashpot damper includes a tubular member having a closed distal end and an open proximal end, and a piston member received within the tubular member. In some embodiments, the tubular member or the piston member is attached to the valve body, and the piston moves relative to the tubular member along an axis of the tubular member in response to movement of the valve body relative to the valve seat. In some embodiments, the pressure relief valve includes a plurality of the air dashpot dampers.