Abstract: A piston of an apparatus is movable within a cavity between a first position wherein a pressure port is in fluid communication with the first fluid chamber and a second position wherein the pressure port is in fluid communication with the second fluid chamber. In further examples, apparatus comprise an expansion chamber that is isolated from the first fluid chamber in a first condition and the expansion chamber is in fluid communication with the first fluid chamber in a second condition. In further examples, methods of operating an apparatus include the step (I) of applying fluid pressure to at least one of the first fluid chamber and the second fluid chamber, and the step (II) of determining a position of the piston within the cavity based on the applied fluid pressure.

Abstract: A check valve apparatus includes at least one first test channel including a first pathway extending through a valve body and in communication with a flow path. The pathway is configured to receive a test stick for inserting through the pathway of the test channel to engage a disc such that the disc moves from the open position to the closed position. In further examples, methods for testing a check valve include the step of moving an end of a test stick to engage a downstream face of a disc such that the disc is moved against a bias of a biasing device from the open position to the closed position. The method further includes the step of inspecting an interior portion of the check valve apparatus.

Abstract: A piston of an apparatus is movable within a cavity between a first position wherein a pressure port is in fluid communication with the first fluid chamber and a second position wherein the pressure port is in fluid communication with the second fluid chamber. In further examples, apparatus comprise an expansion chamber that is isolated from the first fluid chamber in a first condition and the expansion chamber is in fluid communication with the first fluid chamber in a second condition. In further examples, methods of operating an apparatus include the step (I) of applying fluid pressure to at least one of the first fluid chamber and the second fluid chamber, and the step (II) of determining a position of the piston within the cavity based on the applied fluid pressure.

Abstract: A check valve apparatus includes at least one first test channel including a first pathway extending through a valve body and in communication with a flow path. The pathway is configured to receive a test stick for inserting through the pathway of the test channel to engage a disc such that the disc moves from the open position to the closed position. In further examples, methods for testing a check valve include the step of moving an end of a test stick to engage a downstream face of a disc such that the disc is moved against a bias of a biasing device from the open position to the closed position. The method further includes the step of inspecting an interior portion of the check valve apparatus.

Abstract: A check valve includes a valve body having a valve seat, a diffuser, a disc coupled to the diffuser, and a compression spring. The diffuser is positioned inside the valve body and has a forward face. The disc is coupled to and movable relative to the diffuser and has an upstream face and a downstream face. The compression spring biases the disc into a normally open position during forward flow. A check valve apparatus further comprises at least one test bore through the valve member in communication with the disc. A method for testing the operation of a passive check valve is also disclosed.

Abstract: A check valve includes a valve body having a valve seat, a diffuser, a disc coupled to the diffuser, and a compression spring. The diffuser is positioned inside the valve body and has a forward face. The disc is coupled to and movable relative to the diffuser and has an upstream face and a downstream face. The compression spring biases the disc into a normally open position during forward flow. A check valve apparatus further comprises at least one test bore through the valve member in communication with the disc. A method for testing the operation of a passive check valve is also disclosed.