| 摘要 |
A constant flow rate controller valve includes a piston spring biased towards the top of the valve. Fluid or gas flowing into the valve increases the forces in the chamber above the piston, forcing the piston toward a valve seat. The piston is thus seated in the valve seat, blocking gas or fluid flow to the outlet port. The forces on the piston in the chamber below the piston builds as flow goes through the piston until the forces in this chamber including the piston spring force is greater than the forces in the chamber above the piston. The piston then is lifted from the valve seat, and the pathway to the outlet orifice is opened. At equilibrium, fluid or gas flows through or around the piston via the variable orifice. The equilibrium flow rate can be altered through variation of fluid flow through the piston orifice and/or around the piston by a bladder ring which is inflated or deflated, by an elastomeric ring which is compressed by liquid or structural forces, or by a metal or plastic ring that is circumferentially variable by mechanical actuators. Change in the fluid flow through the piston orifice or around the piston alters the flow resistance, Cv. The piston thus moves to an equilibrium position based on the altered flow rate Q.
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