Low Torque Valve Rotor Seal Design
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Solution Overview
Problem
High-pressure valves face challenges in minimizing torque required to turn the rotor due to excessive forces from moveable members pressing against the rotor, which are not effectively reduced despite varying fluid pressures, leading to high friction and difficulty in rotor movement.
Innovation Solution
A high-pressure valve design that incorporates a seal device constrained by a flange fixed to the body, dynamically sealing to a cylindrical surface on the outside of the moveable member, minimizing the dynamic seal diameter and reducing the force applied to the rotor by using a compression spring and a backup ring to maintain contact with the rotor even at zero pressure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If the diameter of the seal surface that dynamically seals to the moveable member is minimized, then the force of the moveable member against the rotor is minimized, but the robustness of the moveable member may be compromised
Solution Approach 1:
The moveable member is designed with non-uniform thickness, being thickest at the front end where it contacts the rotor and progressively thinner toward the rear end. This local variation in quality allows the seal surface diameter to be minimized for reduced force while maintaining sufficient material thickness and robustness at the critical contact region.
2Strength
If the moveable member is made robust with sufficient thickness, then the structural integrity is improved, but the force against the rotor increases leading to higher torque
Solution Approach 1:
The moveable member features variable thickness with the greatest thickness at the front end (where structural integrity is needed) and reduced thickness toward the rear. This localized quality distribution provides structural strength where required while minimizing the overall force against the rotor through reduced seal surface diameter.
3Stability of the object's composition
If the seal device is constrained by a flange fixed to the body, then the position stability is improved, but the device complexity increases due to additional insert components
Solution Approach 1:
The valve body is segmented into functional sections: a main body and a separate insert containing the flange and spring mechanism. This segmentation allows the seal device constraint system to be designed as a modular unit that can be independently optimized for stability while being easily installed and replaced, managing complexity through functional decomposition.
4Reliability
If the spring force is increased to maintain contact at zero pressure, then the sealing reliability is improved, but the total force on the rotor increases
Solution Approach 1:
The spring force is localized to act only on the rear end of the moveable member, providing just enough force to maintain contact between the moveable member and rotor at zero pressure. The variable thickness design ensures that this localized spring force does not translate to increased overall force on the rotor, as the thinnest section of the moveable member is positioned to minimize force transmission.
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
This design achieves a 28% reduction in total forces on the rotor, resulting in lower torque requirements for turning, while maintaining robustness and durability of the moveable members.
Implementation Method 1
a flange (132) fixed to the body (116), with the seal device (121) dynamically sealing to a cylindrical surface on the outside of the moveable member (112)... a compression spring and a backup ring to maintain contact with the rotor even at zero pressure
Data Source
Figure 1~2
Figure 3~6
Figure 7
AI summary
A valve of the type wherein high pressure fluid moves through a first moveable member (112) that lies in a first valve body (116), through a rotor channel (162), and though a second moveable member (150) in a second body, with the rotor being rotatable to direct the fluid into a selected passage of the second body. In this valve, forces on the rotor vary with the pressure of the fluid, but are decreased to reduce friction and therefore reduce rotation torque. Forces on the rotor are decreased by constructing each moveable member with a cylindrical surface (135) that is dynamically sealed against. Each valve body includes a body and an insert (126) threaded into a front end of the body. The insert has an internal flange (132) with a flange front end (133) that abuts the rear of a spring (120) that urges the movable member forward towards the rotor, and with a flange rear end (204) that abuts a seal device (121) that dynamically seals to the cylindrical surface (135) of the moveable member.