A plunger, a hydraulic end and a plunger pump are disclosed. The plunger includes a plunger body, the plunger body includes a flow channel; a first liquid inlet hole is located in the plunger body and passes through the sidewall of the plunger body; the plunger body includes a first end portion and a second end portion, a flow channel extends from the first end portion to the second end portion, a part of the flow channel close to the first end portion is closed, the flow channel extends to the second end portion and forms a first opening, the first liquid inlet hole is communicated with the flow channel, the first valve assembly is located at the first opening, and is configured to allow fluid to flow out from the flow channel at the first opening and prevent fluid from flowing back to the flow channel from outside.

A check valve includes a valve element and a valve body having a body housing, an annular valve seat insert, a bushing, and a biasing member. The body housing includes an outer circumferential wall extending between an inlet port and an outlet port to define a valve cavity therebetween. The valve seat insert is seated in a body seat surface surrounding the inlet port. The bushing is disposed in the valve cavity and defines a central bore, with the bushing including an outboard end surface axially engageable with the valve seat insert. The biasing member is disposed between a bearing portion of the body housing and an inboard end of the bushing to allow for axial movement of the bushing with respect to the body seat surface. The valve element extends through the bushing central bore and is movable between a closed position and an open position.

The check valve includes: an inlet pipe body part (23) which includes an inflow port (23b); an outlet pipe body part (25) which includes an outflow port (25b); a mobile body (a reciprocative body (2)). Insides of the inlet pipe body part, the outlet pipe body part, and the valve body (12) are communicated to form a curved flow path from the inflow port toward the outflow port. The reciprocative body includes a valve element (6). The seat (23c) is arranged so as to be capable of supporting the valve element and the inflow port and the seat are arranged parallel to each other. An inner wall surface (23y) on an outside-corner side of the flow path in the inlet pipe body part is formed so as to curve toward a side of the outlet pipe body part as a position gets closer from the inflow port to the seat.

A pressure relief valve for a two-phase immersion cooling system is configured to support fluid flow rates up to 500 cfm, 550 cfm, 600 cfm, or even 2000 cfm. This, in turn, allows the cooling system to support computing systems with a power density greater than 250 kW. This is accomplished by the valve having a relatively large passage (e.g., 2-6 inch diameter), a relatively large spring (e.g., 1.5-1.7 inch diameter), and a guide rod rigidly coupled to the poppet and slidably coupled to a guide plate. The valve may be used as an outlet valve and coupled to an adsorbent chamber to reduce the loss of coolant from the system as air is vented to an ambient environment. The valve may be used as an inlet valve and coupled to an adsorbent chamber to reduce the intake of water vapor as air from the ambient environment flows into the system.

A check valve for a gas distribution system of an aircraft includes a valve body with a control rod for the valve body, the valve body being intended to slide along a first axis between a closed position in which the valve body engages in use with a seat of the distribution system and an open position in which the valve body is moved away from the seat, the valve comprising a first spring arranged outside the control rod and tending in use to hold the valve body against the seat, the valve comprising an assembly comprising at least one weight and a second spring which are arranged at least partially inside the control rod, the spring being connected at a first of its two ends to the control rod and at a second of its two ends to the weight.

Bypass valves for pool heaters are disclosed. Embodiments may include pool heaters with a heat exchanger, a support, and an automatic bypass valve coupled to the support. The automatic bypass valve may include a cylindrical bypass shaft, and a bypass valve having a non-circular opening configured to receive the bypass shaft, where the bypass valve is configured to slide along the cylindrical bypass shaft responsive to water pressure in the heat exchanger, and where water and debris can flow through the non-circular opening when the bypass valve is in a closed position.

A relief valve for a backflow preventer includes a plunger, a lock nut, and a seal. The plunger has a female fastening section and a first seal engagement surface. The lock nut has a male fastening section and a second seal engagement surface. The male fastening section is received by the female fastening section to bring the first seal engagement surface toward the second seal engagement surface. The seal is positioned between the first seal engagement surface and the second seal engagement surface.