Abstract: An automatic fluid flow control device and method are disclosed. The fluid flow control device provides a constant flow rate of strained fluid despite varying differential pressures and employs a combination of a unitary body with a first valve to open or close the device to fluid flow and an integrated, removable strainer in the form of a cup that encircles an inlet of a removable flow control valve. The body is essentially in the shape of a "Y" and provides a compact valve with minimum threaded joints and access to the various components thereof with minimum disassembly. The removable strainer is configured and arranged in a manner so that fluid flows from the outside to the inside of the cup-shaped strainer, allowing easier use and cleaning.

Abstract: An automatic fluid flow control valve and strainer device which provides a constant flow rate of strained fluid despite varying differential pressures and employs a combination of a unitary body with an integrated, removable strainer assembly and a removable flow control valve assembly. The body is essentially in the shape of a "Y" and provides a compact valve with minimum threaded joints and access to the various components thereof with minimum disassembly. The removable strainer assembly is configured and arranged in a manner so that fluid flows from the outside to the inside of a cup-shaped strainer, allowing easier use and cleaning.

Abstract: Two check valves in series with a zone between them are mounted between the supply pipe and discharge pipe, and a relief valve vents the zone to atmosphere under predetermined pressure conditions in the pipes. A valve poppet in the upstream check valve cooperates with its seat and an enclosing stationary barrel to form a first chamber. An ejector nozzle receives liquid from this first chamber when the valve poppet is open, and discharges it into the zone. The action of the ejector nozzle aspirates a second chamber in the upstream check valve to reduce the pressure drop when the valve is open. The velocity head of the discharge from the ejector nozzle is directed against a valve poppet in the downstream check valve, which also includes a pressure affected piston area. In each check valve the flow restriction across the valve seat decreases more rapidly than the downstream flow restriction.

Abstract: Two identical check valve assemblies are connected in series with a zone between them. A differential control valve vents this zone to atmosphere whenever the downstream pressure approaches the upstream pressure within a predetermined magnitude. The action of the differential control valve is responsive to differential pressure across the upstream check valve.

Abstract: A check valve assembly employs a poppet slidably mounted in a stationary barrel to engage a seat in the barrel. The poppet and barrel cooperate to form a closed chamber containing a spring which acts to close the poppet against the seat, but the force of the spring is partially overcome by a reduction in pressure in the chamber caused by venturi action by forward flow through the check valve assembly with the result that higher upstream pressure is needed to open the valve than to maintain it in open position, at least for low and medium flow rates. Two identical check valve assemblies are connected in series, the assemblies being perpendicular to each other, each mounted at about a 45.degree. angle with respect to coaxial inlet and outlet terminals.

Abstract: Two check valves in series with a zone between them are mounted between the supply pipe and discharge pipe, and a relief valve vents the zone to atmosphere under predetermined pressure conditions in the pipes. A valve poppet in the upstream check valve cooperates with its seat and an enclosing stationary barrel to form a first chamber. A second chamber is formed in the barrel on the other side of the valve poppet, and a third chamber is formed downstream of the valve poppet and the barrel, and constitutes the zone to be vented. An ejector nozzle receives liquid from the first chamber when the valve poppet is open, and discharges it into the zone. The action of the ejector nozzle aspirates the second chamber in the upstream check valve to reduce the pressure drop when the valve is open. The velocity head of the discharge from the ejector nozzle is directed against a valve poppet in the downstream check valve, which also includes a pressure affected piston area.

Abstract: Two identical check valves assemblies are connected in series with a zone between them. A differential control valve vents this zone to atmosphere whenever the downstream pressure approaches the upstream pressure within a predetermined magnitude. The action of the differential control valve is responsive to differential pressure across the upstream check valve.

Abstract: A check valve assembly employs a poppet slidably mounted in a stationary barrel to engage a seat in the barrel. The poppet and barrel cooperate to form a closed chamber containing a spring which acts to close the poppet against the seat, but the force of the spring is partially overcome by a reduction in pressure in the chamber caused by venturi action by forward flow through the check valve assembly with the result that higher upstream pressure is needed to open the valve than to maintain it in open position, at least for low and medium flow rates. Two identical check valve assemblies are connected in series, the assemblies being perpendicular to each other, each mounted at about a 45.degree. angle with respect to coaxial inlet and outlet terminals.