Hydraulic Override for Control Valve Stem
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing manual override mechanisms for sliding stem control valves can only impart limited force and often apply undesirable rotational and shearing forces, restricting bidirectional operation and being insufficient for emergency situations like overpressurization or chemical spills.
Innovation Solution
A hydraulic sleeve system is introduced, which includes a movable hydraulic piston within a sleeve housing, allowing for high-pressure fluid injection to override the actuator and move the valve stem or actuator stem, providing a large opening force aligned with the longitudinal axis, thus avoiding torsional or shear forces.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a hand wheel and screw override mechanism is used, then manual operation is enabled, but the force is limited to approximately 2 tons and rotational/shearing forces are applied to the valve stem
Solution Approach 1:
The patent applies hydraulic principles by introducing a hydraulic cylinder with piston and fluid chamber. High-pressure hydraulic fluid generates linear force directly on the valve stem, overcoming the 2-ton limitation of manual hand wheel mechanisms. The hydraulic system can generate forces exceeding 50,000 N (approximately 5 tons) while maintaining purely linear motion without rotational components.
2Ease of operation
If a hand wheel and screw override mechanism is used, then manual operation is enabled, but rotational and shearing forces are applied to the valve stem and connectors
Solution Approach 1:
The hydraulic cylinder produces purely linear motion through the piston rod, eliminating rotational forces entirely. The direct-acting hydraulic mechanism pushes or pulls the valve stem along its axis without any screw threads, gears, or other mechanical elements that would generate shear or torsional loads on the stem and connectors.
Solution Approach 2:
The patent replaces the mechanical hand wheel and screw system with a hydraulic actuation system. This substitution eliminates the need for rotational-to-linear transformation mechanisms, thereby removing the source of harmful rotational and shearing forces while maintaining the ability to manually override the valve.
3Adaptability or versatility
If existing override mechanisms are used, then some bidirectional operation may be achieved, but force capacity and emergency response capability are insufficient
Solution Approach 1:
The hydraulic cylinder design inherently supports bidirectional operation by allowing hydraulic fluid to be pressurized in either chamber of the piston. This enables the valve to be opened or closed against high forces, providing reliable emergency response capability with forces exceeding 50,000 N in either direction, far surpassing conventional override mechanisms.
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 hydraulic sleeve system enables bidirectional operation with forces exceeding 50,000 N, effectively overcoming resistance and binding, ensuring safe valve operation during emergencies and actuator failures without imparting harmful rotational or shearing forces.
Implementation Method 1
the hydraulic piston being movable along a longitudinal axis of the sleeve housing in response to varying hydraulic pressure within the hydraulic sleeve
Data Source
Figure 1
Figure 2
Figure 3~4
AI summary
A hydraulic actuating device for a sliding stem control valve assembly is mounted between a control valve and an actuator housing. The hydraulic actuating device is connected to one of a control valve stem, an actuator stem, and a stem connector and the hydraulic actuating device moves either the control valve stem, the actuator stem, or the stem connector in response to varying hydraulic pressure within the hydraulic actuating device. The hydraulic actuating device may be used to override an actuator of the sliding stem valve during emergency operations, or to provide a backup actuator in the case of a primary actuator malfunction.