A check valve has an internal gate having an adjustable retention force, such that in the event that if the differential pressure between the upstream and downstream pressure changes, the force required to allow flow through the valve may be adjusted without removal of the valve from the piping system.

The present invention relates to a variable-flow-path air valve for water hammer prevention and a design method. The variable-flow-path air valve includes a valve body with a top provided with an air intake-exhaust port. A ball valve seat and a floating ball are arranged below the air intake-exhaust port. The valve body is provided with at least one swing check valve configured to be opened inward. The swing check valve includes: a swing valve disc connected to a valve body hinge, a variable-flow-path air inlet controlled by the swing valve disc to open and close, a device for limiting the opening degree of the swing valve disc, and a sealing device. In the present invention, the air valve takes in air through the air intake-exhaust port and the variable flow path, and discharges air only through the air intake-exhaust port.

A check valve (1) which comprises an obturator (2) and a biasing mechanism, the biasing mechanism arranged to urge the obturator towards a closed condition, and the check valve further comprising an actuator assembly (5, 7a, 7b) which is arranged to be selectively activated to cause the obturator to be in an open condition, and the check valve comprising a controller which has a control signal input to cause the controller to selectively activate the actuator assembly.

An anti-rat flap member for sewer/draining pipe check is removably attached to the valve body. The valve body defines an interior volume therein which is preferably substantially open and unobstructed (except for the flap member). The flap member acts both as a seal to prevent the back-flow of sewage/drainage water and is normally in a closed position to prevent the passage of rats. The flap member comprises a row of sharp projections attached by known means (such as integrally molded, glued, rivetted or screwed) to the outermost side of the flap member facing the downstream section of the valve. The projections must be at an angle to the surface of the sheet, preferably at an angle which will prevent the rodent from gnawing and biting or even lifting the flap member with their mouth.

In accordance with at least one aspect of this disclosure, an adjustable vent tube joint for passing airflow therethough includes, a first segment, a flange extending radially from an outer diameter of the first segment, configured to mount to the vent tube joint to a structure, a second segment rotatably connected to the first segment, and a third segment rotatably connected to the second segment. In accordance with at least one aspect of this disclosure, an adjustable vent pipe can include, a first segment and a second segment concentric with the first segment, the second segment being slidable relative to the first segment. In accordance with at least one aspect of this disclosure, an insert for an exhaust termination can include, a frame configured to fit within an existing louvered exhaust termination, a hinge member, and a flap operatively connected to the frame via the hinge member configured to open with an exhaust flow to connect a dryer exhaust outlet to an ambient external environment through the exhaust termination.

One or more techniques and/or systems are disclosed for a flap valve in a diaphragm pump. The flap valve includes a body and a self-centering hinge portion. A front portion of the body includes a front surface having a raised portion and a recessed portion. The front surface is configured to form a seal with a surface of the pump when the body is in a closed position, the surface of the pump being at an inlet or an outlet of a pumping chamber. The body is configured to allow a downstream flow of a fluid when the flap valve is in an open position. The self-centering hinge portion is operably connected to the body. The self-centering hinge portion has a dynamically changing longitudinal axis. The body is configured to simultaneously translate and rotate about the dynamically changing longitudinal axis to form the seal.

A check valve for cryogenic fluid includes: a valve body which is formed to have an inlet and an outlet open at both ends thereof, a valve seat which is formed inside the valve body to communicate with the inlet; a disk which is pivoted up and down at the upper end thereof about a pivot axis provided in the valve body to open and close the valve seat; and a sealing member which is made of a metal material shrinkable by cryogenic fluid introduced through the inlet, is provided in the circumferential direction of the valve seat, and when the disk closes the valve seat, is brought into close contact with the edge portion of the disk to produce sealing effects.

A blocking valve has an outer valve body housing a weighted paddle, the weighted paddle having a narrow upper portion with a hitch groove and a wider lower portion, the weighted paddle rotatable around a horizontal pivot, the weighted paddle to lie in a horizontal position during an active flow of liquid and to rotate to a vertical position with the upper portion above the lower portion when the flow of liquid is stopped, and a locking mechanism to engage with the hitch groove to lock the weighted paddle into a vertical position and to block the active flow of liquid when the active flow of liquid is resumed.

In accordance with at least one aspect of this disclosure, an adjustable vent tube joint for passing airflow therethough includes, a first segment, a flange extending radially from an outer diameter of the first segment, configured to mount to the vent tube joint to a structure, a second segment rotatably connected to the first segment, and a third segment rotatably connected to the second segment. In accordance with at least one aspect of this disclosure, an adjustable vent pipe can include, a first segment and a second segment concentric with the first segment, the second segment being slidable relative to the first segment. In accordance with at least one aspect of this disclosure, an insert for an exhaust termination can include, a frame configured to fit within an existing louvered exhaust termination, a hinge member, and a flap operatively connected to the frame via the hinge member configured to open with an exhaust flow to connect a dryer exhaust outlet to an ambient external environment through the exhaust termination.

Disclosed is a magnetic pressure retaining control device, which comprises: a valve seat, a magnetic valve cover, and a trigger magnetic member for repelling the magnetic valve cover; the magnetic valve cover and an open end of the valve seat are movably connected; when the magnetic valve cover is in an open state, the trigger magnetic member is opposite to an end surface of the magnetic valve cover away from an inside of the valve seat. A cylindrical magnet is also arranged in the valve seat. By the magnetic between the trigger magnet and the magnetic valve cover, and the magnetic between the magnetic valve cover and the valve seat, a reliable guarantee for the closure between the magnetic valve cover and the valve seat is provided. The valve seat and the valve cover are tightly closed under different conditions.