A backflow prevention assembly includes a body forming two buckets, wherein flow passes through the body from an inlet to an outlet along an axis and consecutively through each of the buckets. A single zone test cover encloses a first of the buckets to form a single zone chamber. A dual zone test cover encloses a second of the buckets with a dual zone cartridge assembly therein. The dual zone test cover has two test cocks. The dual zone cartridge assembly includes a frame having a valve seat, wherein the frame includes a lumen providing fluid communication from a dual zone chamber upstream of the valve seat to a first of the two test cocks of the dual zone test cover, and wherein the second of the two test cocks of the dual zone test cover is in fluid communication with the dual zone chamber downstream of the valve seat.

An oil returning valve set with multi-stage throttling control includes an oil returning channel implemented in oil in an oil hydraulic equipment. The two ends of the oil returning channel are connected to a pressurized oil collecting cavity and a pressurized oil discharging cavity respectively. A plurality of throttling valve plugs and oil returning valve plug are arranged in the oil returning channel, and a normally-open draining gap is also formed among the plurality of throttling valve plugs. When the oil returning valve plug is opened, a plurality of the throttling valve plugs are arranged in series to generate multi-stage throttling oil hydraulic draining control, which improves the problem that the valve opening allowance of the throttling valve for oil returning and pressure relief of traditional oil hydraulic equipment is not sufficient.

Pivot valves have a valve seat and a valve closure mounted for pivoting movement through a closure chamber in a passage. The pivot valves may be selectively set in a check mode and an open mode. Flapper valves have a hydrofoil extending from a flapper. Valve assemblies comprise the pivot valves and flapper valves and have an open condition, a check condition, and a shut-off condition.

A backflow prevention assembly includes a body forming two buckets, wherein flow passes through the body from an inlet to an outlet along an axis and consecutively through each of the buckets. A single zone test cover encloses a first of the buckets to form a single zone chamber. A dual zone test cover encloses a second of the buckets with a dual zone cartridge assembly therein. The dual zone test cover has two test cocks. The dual zone cartridge assembly includes a frame having a valve seat, wherein the frame includes a lumen providing fluid communication from a dual zone chamber upstream of the valve seat to a first of the two test cocks of the dual zone test cover, and wherein the second of the two test cocks of the dual zone test cover is in fluid communication with the dual zone chamber downstream of the valve seat.

A valve assembly having a body forming a bucket having a sidewall extending between an open end and a closed end along a bucket axis. A first conduit and a second conduit extend from the sidewall, wherein the first and the second conduits extend along a conduit axis that is perpendicular to the bucket axis. A frame inserts into the bucket along the bucket axis and includes a valve seat and a valve member biased against the valve seat. A guide is provided in the bucket between the closed end and the frame and extends along a guide axis between a first opening arranged in a first plane and aligned to receive fluid flow from the first conduit and a second opening arranged in a second plane and aligned to direct fluid flow through the valve seat. The first and second planes are not parallel to one another.

A valve assembly with a spring retention assembly including an elongated cylinder portion having an open threaded end and a closed end and an elongated piston portion having a free end and a threaded tab end configured to thread through the open threaded end and, thereby, be slideably captured in the cylinder portion. A spring couples to the body portion and the piston portion to provide a force to urge the body portion and the piston away from one another, wherein the closed end and the free end are similarly shaped so that the spring retention assembly can be reversibly mounted to a valve member that can also be reversibly mounted.

A ventilation flow rate regulator for a pressurised tank of a vehicle. The regulator includes a body including a gas inlet and a gas outlet, and at least one restrictor mounted movably relative to the body. The restrictor is mounted to reduce a cross-section of at least one path of a gas flow proceeding from the inlet to the outlet, when a flow rate at the inlet is greater than a predetermined threshold. The regulator is arranged so that the cross-section remains non-zero irrespective of a flow rate.

Various implementations include a device for pumping grout. The device includes a body and a pump. The body defines a first opening, a second opening, and a third opening. Each of the first, second, and third openings is in fluid communication with each other. The first opening includes a first one-way valve configured to allow the flow of grout toward the second and third openings, and the second opening includes a second one-way valve configured to allow the flow of grout away from the first and third openings. The pump is sealingly coupled to the third opening and in fluid communication with the first and second openings. The pump is configured to increase and decrease pressure within the body to cause the flow of grout from the first opening to the second opening.

An oil returning valve set with multi-stage throttling control includes an oil returning channel implemented in oil in an oil hydraulic equipment. The two ends of the oil returning channel are connected to a pressurized oil collecting cavity and a pressurized oil discharging cavity respectively. A plurality of throttling valve plugs and oil returning valve plug are arranged in the oil returning channel, and a normally-open draining gap is also formed among the plurality of throttling valve plugs. When the oil returning valve plug is opened, a plurality of the throttling valve plugs are arranged in series to generate multi-stage throttling oil hydraulic draining control, which improves the problem that the valve opening allowance of the throttling valve for oil returning and pressure relief of traditional oil hydraulic equipment is not sufficient.

A check valve comprises a valve housing defining an opening and a plurality of flapper elements each having a proximal end and a distal end. The flapper elements are pivotally mounted to the valve housing at their proximal ends for pivotal movement between a closed position, in which they block the flow of fluid through the opening and an open position in which they permit the flow of fluid through the opening. Each flapper element is generally triangular or trapezoidal in shape such that the flapper elements together create a generally conical or frustoconical surface when the valve is in the closed position. A resilient band extending around a circumference of the conical or frustoconical surface defined by the plurality of flapper elements in the closed position for biasing the flapper elements towards the closed position.