Fluid-Damped Check Valve for Chatter and Surge Protection
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Solution Overview
Problem
Conventional check valves are prone to 'chattering' and damage from high-pressure transients due to rapid opening and closing, and internal component acceleration, which leads to wear and potential damage.
Innovation Solution
A check valve assembly with a damping chamber containing viscous or incompressible fluid that slows the movement of the piston assembly, preventing rapid oscillation and high-velocity impacts by using a damping fluid to counteract the acceleration of the poppet, and sealing members to prevent fluid contamination and leakage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional check valves are used with spring or hinge biasing, then the valve can maintain closed position and prevent backflow, but the valve is prone to rapid opening and closing (chatter) under certain flow conditions
Solution Approach 1:
A dashpot mechanism is introduced as an intermediary damping element between the poppet and the valve body. This dashpot provides controlled resistance to poppet movement, slowing down the opening and closing speeds while maintaining the valve's ability to prevent backflow. The damping action reduces chatter by preventing rapid oscillations.
Solution Approach 2:
The valve incorporates adjustable damping parameters through the dashpot mechanism, allowing control over the poppet's movement characteristics. By adjusting the damping coefficient, the valve can operate stably across different flow conditions without excessive opening/closing speeds that cause chatter.
2Reliability
If conventional check valves are used with spring or hinge biasing, then the valve can prevent backflow, but the valve is susceptible to surge damage from high-pressure transient waves
Solution Approach 1:
The dashpot mechanism provides beforehand cushioning by damping the poppet's acceleration before high-pressure transient waves can cause surge damage. The damping force acts in advance to limit the maximum velocity and impact force of the poppet during pressure surges, protecting the valve from damage.
Solution Approach 2:
The high-pressure transient waves that would normally cause harmful surge damage are converted into a beneficial damping effect. The dashpot mechanism transforms the kinetic energy from pressure surges into controlled damping forces, dissipating the energy harmlessly and protecting the valve components.
3Ease of operation
If the valve is designed to be flow sensitive with low cracking pressure, then the valve opens easily during normal flow, but the valve can rapidly oscillate under certain flow conditions
Solution Approach 1:
The dashpot acts as an intermediary damping element that stabilizes the poppet's movement during flow transitions. It provides sufficient damping to prevent rapid oscillations while allowing the valve to open easily during normal flow conditions by accommodating the poppet's movement through controlled resistance.
Solution Approach 2:
The valve incorporates dynamic damping characteristics through the dashpot mechanism, allowing the damping force to vary with the poppet's velocity. This dynamic damping provides stability during oscillatory conditions while maintaining ease of operation during normal flow by adapting to the instantaneous movement conditions.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution effectively reduces wear on internal components and prevents damage by damping the movement of the piston assembly during pressure fluctuations and high-pressure transients, preventing chattering and excessive acceleration.
Implementation Method 1
a damping chamber (108) containing a damping fluid (152) configured to damp movement of the piston assembly (120)
Implementation Method 2
a first sealing member (142) configured to prevent the operating fluid (150) from flowing into the damping chamber (108), and a second sealing member (144) configured to prevent the damping fluid (152) from flowing into the flow chamber (104)
Data Source
AI summary
Fluid damped check valves are described herein. A representative check valve includes a piston assembly movably positioned within a housing. The housing can include a flow chamber, a damping chamber containing a damping fluid, and a leak chamber fluidly coupled between the flow chamber and the damping chamber. The piston assembly can include a poppet positioned in the flow chamber, and a flange positioned in the damping chamber. In operation, the piston assembly is movable between (i) a closed position in which the poppet sealingly engages the housing to at least inhibit fluid flow through the flow chamber and (ii) an open position in which the poppet disengages from the housing and permits fluid flow through the flow chamber. When the piston assembly moves between the open and closed positions, the flange moves through the damping fluid in the damping chamber to slow the movement of the poppet.