A check valve includes a valve body defining a valve bore extending from a first axial end to a second axial end, the valve body including an annular body and a cross member secured to and extending across the valve bore from the annular body on one side of the valve body to the annular body on an opposite side of the valve body, the valve bore at the cross member divided into more than one portion by the cross member; a position block extending from the cross member; a valve member positioned within the valve body and configured to rotate between an open position and a closed position; and a pivot pin extending from the valve member, engaged with the position block, and fixed with respect to the valve member; the valve member and the pivot pin configured to rotate together between the open position and the closed position.

A check valve can include a valve body defining a valve bore, the valve body comprising an annular body and a cross member secured to and extending in a radial direction across the valve bore from the annular body on one side of the valve body to the annular body on an opposite side of the valve body, the valve bore at the cross member divided into more than one portion by the cross member; a position block extending from the cross member; a pair of valve members, each valve member of the pair of valve members positioned within the valve body and configured to rotate between open and closed positions; and a pivot pin positioned within the valve body and extending through the position block and each valve member of the pair of valve members, the pivot pin being supported only by the position block.

A check valve for a fluid distribution system can include a valve body defining a valve bore defining a cylindrical shape, the valve body comprising an annular body and a fixed cross member secured to the valve body and extending across the valve bore, a position block secured to the cross member of the valve body, extending from the cross member, and defining a pivot bore; a pivot pin positioned within the valve body and extending through the pivot bore of the position block, the pivot pin positioned entirely within the cylindrical shape of the valve bore; and a valve member positioned within the valve body and configured to rotate about the pivot pin to a closed position when a pipe system termination fitting attached to the valve body is dislocated fr om the valve body or when the fluid moves in a negative flow direction of the check valve.

A check valve includes a valve body defining a valve bore extending from a first axial end to a second axial end, the valve body including an annular body and a cross member secured to and extending across the valve bore from the annular body on one side of the valve body to the annular body on an opposite side of the valve body, the valve bore at the cross member divided into more than one portion by the cross member; a position block extending from the cross member; a valve member positioned within the valve body and configured to rotate between an open position and a closed position; and a pivot pin extending from the valve member, engaged with the position block, and fixed with respect to the valve member; the valve member and the pivot pin configured to rotate together between the open position and the closed position.

A check valve can include a valve body defining a valve bore, the valve body comprising an annular body and a cross member secured to and extending in a radial direction across the valve bore from the annular body on one side of the valve body to the annular body on an opposite side of the valve body, the valve bore at the cross member divided into more than one portion by the cross member; a position block extending from the cross member; a pair of valve members, each valve member of the pair of valve members positioned within the valve body and configured to rotate between open and closed positions; and a pivot pin positioned within the valve body and extending through the position block and each valve member of the pair of valve members, the pivot pin being supported only by the position block.

A check valve for a fluid distribution system can include a valve body defining a valve inner cavity defining a valve bore extending from a first axial end to a second axial end; a position block secured to the valve body and defining a pivot bore; a pivot pin positioned within the valve body and extending through the pivot bore of the position block; and a valve member positioned within the valve body and configured to rotate about the pivot pin from an open position to a closed position, the valve member configured to remain in the open position as long as a fluid in the fluid distribution system is moving in a positive flow direction of the check valve, the valve member further configured to close when the fluid is moving in a negative flow direction of the check valve.

A flapper assembly for an aspirator system includes a flapper plate and a valve assembly. The flapper plate defines a first plurality of apertures. The valve assembly includes a first valve plate disposed over the first plurality of apertures and a first pressure relief assembly arranged to move the first valve plate relative to the flapper plate.

A check valve including a valve housing defining a pair of valve openings; a pair of flappers pivotably mounted for rotation relative to the housing between an open position in which they permit fluid flow through the respective valve openings and a closed position in which they prevent fluid flow through the valve openings; and a stop element arranged such that the flappers will contact the stop element in their open positions. Each flapper includes a primary flapper element pivotally mounted to a hinge pin that extends across the valve, and a secondary flapper element. The primary flapper element further includes at least one flapper opening formed therethrough. The secondary flapper element is pivotally mounted such that it may rotate relative to the primary flapper element for opening and closing the at least one flapper opening in the primary flapper element.

A flapper assembly for an aspirator system includes a flapper plate and a valve assembly. The flapper plate defines a first plurality of apertures. The valve assembly includes a first valve plate disposed over the first plurality of apertures and a first pressure relief assembly arranged to move the first valve plate relative to the flapper plate.

A flow-controlling unit provided in a flow channel is disclosed. The flow-controlling unit provided in a flow channel, according to one embodiment of the present invention, comprises: a plate which is disposed perpendicular to the moving direction of a fluid in a flow channel, and on which are formed multiple fluid through-holes through, which the fluid passes; and one or more flow-controlling pieces which are provided in a position corresponding to the fluid through-holes, form an inclination with respect to the plate in the direction of the inflow of the fluid, are capable of tilting on the plate, and control the degree of opening of the fluid through-holes by being tilted due to pressure applied from hydraulic pressure of the fluid.