A device and method are described for extending the life of check valves. An improved check valve having a double poppet and tapered guides is more robust, and a check valve protection device between the check valve and the environment into which fluid is injected protects the valve from a contaminating or corrosive environment. The check valve and check valve protection device are small and light weight to prevent vibration-induced failures. The check valve protection device preferably has an interior volume that fills quickly by relatively few cycles of the lubricant pump to reduce delay of lubricant to the injection point.

Pressure-relief valves are disclosed. A valve for conveying fluid includes a body, a valve seat, and a valve seat disc. The body includes a plurality of inner surfaces. The valve seat includes a curved outer surface. A first portion of the curved outer surface is configured to contact at least one of the plurality of inner surfaces of the body to secure the valve seat in the body. The valve seat disc is configured to move between a closed position at which the valve seat disc sealingly engages a second outer portion of the curved outer surface of the valve seat and an open position at which the valve seat disc is disengaged from the curved outer surface of the valve seat.

A valve assembly having a seat, a valve body, and a seal. The valve body has an outer circumferential surface defined by an upper planar surface, a lower planar surface, and a groove disposed between the upper planar surface and the lower planar surface. The seal is coupled to the outer circumferential surface of the valve body. The valve body and the seal are movable into engagement with the seat to form a seal.

An apparatus can include a housing, a plunger configured to reciprocate along an axis within the housing, and an internal fluid chamber disposed in the housing. A valve, having a valve base and a deformable seal, can also be included in the apparatus. The apparatus can further include a seat having an aperture therein. The valve is configured to move into and out of contact with the seat when the plunger reciprocates within the housing, based upon a fluid pressure in the internal flow chamber. In addition, an outer diameter of the deformable seal of the valve is less than an outer diameter of the seat.

Pressure-relief valves are disclosed. A valve for conveying fluid includes a body, a valve seat, and a valve seat disc. The body includes a plurality of inner surfaces. The valve seat includes a curved outer surface. A first portion of the curved outer surface is configured to contact at least one of the plurality of inner surfaces of the body to secure the valve seat in the body. The valve seat disc is configured to move between a closed position at which the valve seat disc sealingly engages a second outer portion of the curved outer surface of the valve seat and an open position at which the valve seat disc is disengaged from the curved outer surface of the valve seat.