A double check valve is provided that includes an in-line inlet check valve and an outlet check valve that cooperate to prevent back flow of fluid through the valve. The check valve also includes at least one vent that allows for fluid trapped within the check valve to drain, thereby preventing freezing of the check valve and hydrant to which it is interconnected. The check valve provided omits many superfluous components and thus is smaller and easier to install than check valves of the prior art.

A double check valve is provided that includes an in-line inlet check valve and an outlet check valve that cooperate to prevent back flow of fluid through the valve. The check valve also includes at least one vent that allows for fluid trapped within the check valve to drain, thereby preventing freezing of the check valve and hydrant to which it is interconnected. The check valve provided omits many superfluous components and thus is smaller and easier to install than check valves of the prior art.

A valve member for a spring-loaded valve assembly includes a top portion having a spring retaining recess, the spring retaining recess extending into the top portion to form a void space, the void space to receive at least one coil of a spring, the spring retaining recess having a recess diameter that is smaller than a top portion diameter, wherein the recess diameter is larger than a rest diameter of a spring base including the coil, the spring retaining recess blocking expansion of the at least one coil when the spring is compressed. The valve member also includes a bottom portion coupled to the top portion. The valve member further includes a sealing element positioned axially below a shoulder of the top portion and legs coupled to the bottom portion.

A control valve includes a piston-housing having a hollow portion. The hollow portion has a first end, an open end, first and second internal chambers, and a fluid port configured to allow fluid to exit the second chamber. The first chamber is nearer the first end, and the second chamber is nearer the open end. A piston is located within the housing and is adapted for reciprocal motion. The piston includes a first and second seal-engaging portions. The first seal-engaging portion has a diameter that is less than the diameter of the second seal-engaging portion.

A double check valve is provided that includes an in-line inlet check valve and an outlet check valve that cooperate to prevent back flow of fluid through the valve. The check valve also includes at least one vent that allows for fluid trapped within the check valve to drain, thereby preventing freezing of the check valve and hydrant to which it is interconnected. The check valve provided omits many superfluous components and thus is smaller and easier to install than check valves of the prior art.

A double check valve is provided that includes an in-line inlet check valve and an outlet check valve that cooperate to prevent back flow of fluid through the valve. The check valve also includes at least one vent that allows for fluid trapped within the check valve to drain, thereby preventing freezing of the check valve and hydrant to which it is interconnected. The check valve provided omits many superfluous components and thus is smaller and easier to install than check valves of the prior art.

The present invention discloses a compressor comprising: an outer pipe being connected from an outside to pass through the vessel; an inner pipe being closely inserted into the outer pipe; a compression mechanism including a suction hole formed of a blind hole and a suction valve in the suction hole. The suction valve includes a seal on a side facing an opening of the suction hole to seal an entire end of the inner pipe on a side facing the suction valve when the compressor stops.

A method and a system control flow of fluid from a storage tank through a supply line to an end user. The system includes a valve that in its open position allows fluid flow from the storage tank to the end user and closes when the pressure in the fluid supply line drops below a predetermined set point. The storage tank is thereby isolated because the valve prevents fluid from flowing from the storage tank to the supply line when the pressure in the supply line is lower than a predetermined upper limit of the storage tank pressure. An end use that is particularly suited to the present system and method is a fuel storage and supply system for a natural gas powered internal combustion engine.

A check valve assembly (100, 200) is provided for subsea applications. The check valve assembly comprises a housing (102, 202), having an inlet port (106, 206) and an outlet port (108, 208) forming an internal fluid passageway through the housing; a valve member (112, 212), moveable within the internal fluid passageway between a first position, where fluid flow through the internal fluid passageway is prevented, and a second position, where fluid flow through the internal fluid passageway is permitted; a biasing member (110, 210), adapted to urge the valve member into the first position at a predetermined cracking force, and a pressure interface (116, 216). The pressure interface operatively links the valve member and an external fluid of a region exterior of the check valve assembly so as to provide a supplemental force, proportional to the ambient pressure of the external fluid, adapted to urge the valve member towards the first position.

The present invention relates to apparatuses for managing the flow of fluids, such as, for example, water, through pipes. Specifically and without being bound by theory, the apparatuses of the present invention creates a backward pressure in fluid traversing a pipe, wherein the backward pressure within the pipe provides compression to the fluid effectively compressing entrapped gas bubbles within the fluid, allowing more accurate water meter measurements. Moreover, the apparatuses of the present invention provide backflow prevention. Embodiments include housing that may be disposed in-line with pipe sections having a width or diameter that is the same as or similar to the pipe sections connected thereto. Systems and methods for managing fluids are further provided.