A check valve may be used to enable desired flow rates of fluid in a particular direction. In some examples, the check valve may have a hollow cylindrical body and a threaded portion on an exterior wall of the hollow cylindrical body such that the check valve may be coupled with an assembly, such as an adapter for a vehicle engine. The check valve may include a plunger having a dome shaped portion (e.g., cone shaped, semi-hemispherical shaped, rounded cone shaped, etc.) that extends out of the hollow cylindrical body into free space when the check valve is in an open position and forms a seal with the hollow cylindrical body when the check valve is in a closed position.

A check valve may be used to enable desired flow rates of fluid in a particular direction. In some examples, the check valve may have a hollow cylindrical body and a threaded portion on an exterior wall of the hollow cylindrical body such that the check valve may be coupled with an assembly, such as an adapter for a vehicle engine. The check valve may include a plunger having a dome shaped portion (e.g., cone shaped, semi-hemispherical shaped, rounded cone shaped, etc.) that extends out of the hollow cylindrical body into free space when the check valve is in an open position and forms a seal with the hollow cylindrical body when the check valve is in a closed position.

A method for protecting a pressure transducer from fluid pressure damage using a pressure isolation mechanism is disclosed. The method includes associating the pressure transducer with an isolation port of the pressure isolation mechanism, placing a pressurizing device for delivering fluid under pressure in fluid connection with an inlet port of the pressure isolation mechanism, and actuating the pressurizing device to cause fluid flow in the inlet port such that a free floating, fluid flow responsive valve member positioned in an internal cavity of the pressure isolation mechanism engages a seal seat therein to attain a closed position, preventing fluid flow between the inlet port and the isolation port and thus prevent overpressure in the isolation port. Hemodynamic pressure signals read with the pressure transducer may be transmitted at least in part through a body of the valve member, or a portion thereof, when in the closed position.

Disclosed is a two-way check/bypass valve assembly connected between the hot and cold-water standpipes under the sink that allows convective circulation of hot water from an existing water heater, through the existing hot water distribution pipes, through the valve assembly to the cold water standpipe, through the existing cold water standpipe and distribution pipes, and back into the water heater. The convective water flow is induced by the temperature difference between the hot water in the pipe rising above the water heater, and the slightly cooled, and denser, water flowing back down into the water heater. The valve will allow this low circulation water flow so long as both hot and cold faucets at the outlet are closed, and will prevent any cross flow between the hot and cold pipes under the sink when either the hot or cold faucet is opened.

Disclosed is a two-way check/bypass valve assembly connected between the hot and cold-water standpipes under the sink that allows convective circulation of hot water from an existing water heater, through the existing hot water distribution pipes, through the valve assembly to the cold water standpipe, through the existing cold water standpipe and distribution pipes, and back into the water heater. The convective water flow is induced by the temperature difference between the hot water in the pipe rising above the water heater, and the slightly cooled, and denser, water flowing back down into the water heater. The valve will allow this low circulation water flow so long as both hot and cold faucets at the outlet are closed, and will prevent any cross flow between the hot and cold pipes under the sink when either the hot or cold faucet is opened.

The fluid delivery system includes a pressurizing device for delivering a pressurized injection fluid, a low pressure fluid delivery system, and a pressure isolation mechanism adapted for fluid communication with the pressurizing device and low pressure fluid delivery system. The pressure isolation mechanism includes a housing defining an inlet port, an isolation port, and an internal cavity. The housing defines a seal seat in the internal cavity between the inlet port and isolation port. A valve member is disposed in the internal cavity. The valve member is free floating in the internal cavity and is adapted to engage the seal seat. The valve member has an open position permitting fluid communication between the inlet port and isolation port, and is fluid flow responsive to fluid flow in the inlet port to engage the seal seat and attain a closed position preventing fluid flow between the inlet port and isolation port.