Valve Plug O-Ring Switching for Pressure-Assisted Closing
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Solution Overview
Problem
Existing control valves for liquid distribution systems face challenges in maintaining a closed position without the need for larger or modified actuators, especially for larger valves with larger seats, which incur significant investment costs.
Innovation Solution
A valve design that utilizes the pressure differential of the controlled liquid to enhance the closing force by employing a second O-ring that switches between inactive and active sealing states, primarily activated near the closed position, reducing unnecessary friction and actuator burden.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If larger actuators or modified mechanics are provided to ensure sufficient closing force for larger valves, then the closing force is sufficient to maintain the valve plug in closed position, but the investment cost increases significantly
Solution Approach 1:
The valve plug utilizes the upstream pressure of the liquid itself to generate closing force through its circumferential wall portion. The pressure differential between upstream (P1) and downstream (P2) creates a force that acts on the rear end of the circumferential wall, assisting the actuator in maintaining the closed position. This self-service mechanism reduces the burden on the actuator without requiring larger or more expensive components.
Solution Approach 2:
The invention employs hydraulic pressure from the liquid flow to generate closing force. The upstream pressure P1 acting on the rear end of the circumferential wall portion of the valve plug creates a hydraulic force that contributes to keeping the valve closed. This hydraulic assistance allows smaller, less expensive actuators to suffice for larger valves.
2Reliability
If the second O-ring remains in active sealing state continuously, then sealing is ensured, but friction increases unnecessarily during valve plug movement
Solution Approach 1:
The second O-ring transitions dynamically between inactive and active sealing states based on the position of the valve plug. During opening movement, the O-ring remains inactive to minimize friction. When the valve plug approaches the closed position and passes the predefined intermediate position, the O-ring becomes active to ensure sealing. This dynamic state change optimizes both operation ease and sealing reliability.
Solution Approach 2:
The second O-ring engages in periodic sealing action rather than continuous sealing. It activates only during the critical phase when the valve plug is near the closed position and passes the intermediate position, then deactivates during opening movement. This periodic engagement reduces unnecessary friction while maintaining sealing when required.
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 provides sufficient closing force with reduced actuator requirements, minimizing friction and operational costs, while maintaining the valve plug in the closed position effectively.
Implementation Method 1
liquid flowing between the inlet and the valve plug has an upstream pressure (P1) and liquid flowing between the valve plug and the outlet has a downstream pressure (P2) which is lower than the upstream pressure (P1)
Data Source
Figure 1
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AI summary
A valve (1) comprises a valve plug (2) having a circumferential wall portion (16) which encircles a first guide part (26) and is encircled by a second guide part (28). A first sealing O-ring (18) is provided between the first guide part and the encircling circumferential wall portion. A second O-ring (20) is provided between the second guide part and the encircled circumferential wall portion. The second O-ring has an inactive non-sealing state in which a rear end (24) of the circumferential wall portion is subjected to a lower downstream pressure (P2), and an active sealing state in which the second O-ring provides a seal between the second guide part and the circumferential wall portion and in which the rear end of the circumferential wall portion is subjected to a higher upstream pressure (P1). In a forward movement, when the valve plug passes a predefined intermediate position, the second O-ring is caused to change to its active sealing state and remain so when the valve plug is in said closed position.