Fluid-damped valve
A fluid-damped valve comprises a body defining an internal cavity having an inlet for ingress of a fluid and an outlet for egress of the fluid, and a closure member having a narrowed end portion. The closure member is movably disposed within the internal cavity intermediate the fluid inlet and the fluid outlet. The valve includes a seat configured to sealingly receive the closure member. The seat defines a constricted portion of the internal cavity configured to non-sealingly receive the narrowed end portion and damp the flow of the fluid through the fluid-damped valve.
1. A fluid-damped valve comprising: a valve body configured to form an inlet for ingress of a fluid and an outlet for egress of the fluid, and an internal cavity which provides an internal flow path configured to allow fluid to flow through the valve body; a reciprocating closure member which is movably disposed in the internal cavity moveable between a valve-closed position that shuts off fluid flow through the internal flow path, and a valve-open position that permits fluid to flow through the valve body from the inlet to the outlet, the reciprocating closure member having a main closure body portion and a narrowed end portion extending away from the main closure body portion towards the inlet; the valve body comprising a valve seat configured to sealingly contact the reciprocating closure member and form a barrier to fluid flow through the internal flow path from the inlet to the outlet when the reciprocating closure member is in the valve-closed position, the internal cavity comprising; a constricted cavity part adjacent to the inlet and upstream of the valve seat which is configured to have a width that non-sealingly receives the narrowed end portion, a damping fluid cavity part downstream of the valve seat configured to have a width greater than the constricted cavity part and to provide a close fitting clearance fit between the main closure body portion and the valve body, when the main closure body portion is at least partially within the damping fluid cavity part, and a valve open cavity part between the damping fluid cavity part and the outlet configured to have a width greater than the damping fluid cavity part and permit fluid to flow past the main closure body portion, between the main closure body portion and the valve body, in the valve open position, wherein as the reciprocating closure member moves from the valve-open position to the valve-closed position, the main closure body portion moves from the valve open cavity part into the damping fluid cavity part and the narrowed end portion moves into the constricted cavity part, where the narrowed end portion restricts fluid flow and damps the movement of the reciprocating closure member towards the valve seat.
2. A fluid-damped valve defined by claim 1 , wherein the valve seat is configured to seal the reciprocating closure member to the valve body in an axial direction and defines an aperture at the constructed portion.
3. A fluid-damped valve defined by claim 1 , wherein the narrowed end portion is associated with the inlet.
4. A fluid-damped valve defined by claim 1 , wherein the main closure body portion sealingly contacts the seat for sealing against the body in the internal cavity.
5. A fluid-damped valve defined by claim 4 , wherein the narrowed end portion extends from the head portion in an axial direction.
6. A fluid-damped valve defined by claim 4 , wherein the narrowed end portion comprises a substantially cylindrical plug.
7. A fluid-damped valve defined by claim 4 , wherein the narrowed end portion has a cross sectional area that decreases along its length in a direction away from the head portion.
8. A fluid-damped valve defined by claim 7 , wherein the narrowed end portion tapers inwardly from the head portion to its free end remote from the head portion.
9. A fluid-damped valve defined by claim 8 , wherein the narrowed end portion has a parabolic configuration.
10. A fluid-damped valve defined by claim 8 , wherein the narrowed end portion has a frusto-conical configuration.
11. A fluid-damped valve defined by claim 1 , that is a one of a check-valve, a non-return valve and a foot-valve.
12. A fluid-damped valve defined by claim 1 , that is sliding piston valve.
13. A fluid-damped valve defined by claim 1 , that is a poppet valve.
14. A fluid-damped valve defined by claim 1 , including a fluid conduit in fluid communication with the fluid inlet and the internal cavity and wherein the valve is a non-return valve.
15. A fluid-damped valve comprising: a valve body configured to form an inlet for ingress of a fluid and an outlet for egress of the fluid, and an internal cavity which provides an internal flow path configured to allow fluid to flow through the valve body; a reciprocating closure member which is movably disposed in the internal cavity moveable between a valve-closed position that shuts off fluid flow through the internal flow path, and a valve-open position that permits fluid to flow through the valve body from the inlet to the outlet, the reciprocating closure member having a main closure body portion and a narrowed end portion extending away from the main closure body portion towards the inlet; the valve body comprising a valve seat configured to sealingly contact the reciprocating closure member and form a barrier to fluid flow through the internal flow path from the inlet to the outlet when the reciprocating closure member is in the valve-closed position, the internal cavity comprising: a constricted cavity part adjacent to the inlet and upstream of the valve seat which is configured to have a width that non-sealingly receives the narrowed end portion, a damping fluid cavity part downstream of the valve seat configured to have a width greater than the constricted cavity part and to provide a close fitting clearance fit between the main closure body portion and the valve body, when the main closure body portion is at least partially within the damping fluid cavity part, and a valve open cavity part between the damping fluid cavity part and the outlet configured to provide a greater clearance between the main closure body portion and the valve body than that provided by the damping fluid cavity part to thereby permit fluid to flow past the main closure body portion, between the main closure body portion and the valve body, when the valve member is in the valve open position, wherein as the reciprocating closure member moves from the valve-open position to the valve-closed position, the main closure body portion moves from the valve open cavity part into the damping fluid cavity part and the narrowed end portion moves into the constricted cavity part, where the narrowed end portion restricts fluid flow and damps the movement of the reciprocating closure member towards the valve seat.
16. A method of preventing liquid hammer in a pipeline installation for conveying a liquid, the method comprising: a pipeline having an inlet end and an outlet end; a fluid damped valve as defined in claim 1 operatively connected in series with the pipeline between the inlet end and the outlet end, wherein when the reciprocating closure member moves towards the valve closed position in response to changes in flow or pressure within the internal cavity, the narrowed end portion is forced into the constricted cavity part of the internal cavity and restricts fluid flow from the damping fluid cavity part past the narrowed end portion towards the inlet, and damps movement of the reciprocating closure member towards the valve seat to reduce the velocity at which the reciprocating closure member impacts the valve seat.
17. A method of preventing liquid hammer in a pipeline installation according to claim 16 , wherein the reciprocating closure member moves towards the valve closed position because the liquid pressure in the pipeline is higher downstream of the outlet of the fluid damped valve, than upstream of the inlet thereof.
18. A method of preventing liquid hammer in a pipeline installation according to claim 16 , wherein the closure member moves towards the valve closed position because the flow of liquid through the pipeline is interrupted.
19. A method of preventing liquid hammer in a pipeline installation according to claim 16 , wherein the liquid is water or coolant in an HVAC system.