Hydraulic Actuating Device for Sliding Stem Control Valve
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Solution Overview
Problem
Existing manual override mechanisms for sliding stem control valves are limited in force application, often restricted to one direction, and can impose undesirable rotational and shearing forces due to size and material constraints, making them inadequate for emergency situations or high-force requirements.
Innovation Solution
A hydraulic sleeve or press system is integrated into the sliding stem control valve assembly, allowing for high-force, directional-independent operation by varying hydraulic pressure to move the valve stem and actuator stem, eliminating rotational and shearing forces through a piston-driven mechanism.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a hand wheel and screw override mechanism is used, then manual operation capability is provided, but the force application is limited to approximately 2 tons and rotational/shearing forces are imposed on the valve stem
Solution Approach 1:
The patent employs a hydraulic actuator system where hydraulic fluid under pressure acts on a piston to generate linear force directly on the valve stem. This hydraulic mechanism eliminates the need for manual hand wheel operation while providing significantly higher force capability (exceeding 2 tons) and avoiding rotational/shearing forces by applying force in a purely linear direction along the valve stem axis.
2Ease of operation
If a hand wheel and screw override mechanism is used, then manual operation is possible, but the mechanism can only operate the valve in one direction
Solution Approach 1:
The hydraulic actuator system is designed with bidirectional control capability, allowing hydraulic pressure to be applied to move the piston in either direction along the linear axis. This dynamic control enables the valve to be operated in both opening and closing directions, as well as any intermediate position, eliminating the unidirectional limitation of hand wheel mechanisms.
3Ease of operation
If a hand wheel and screw mechanism is used, then manual override is achieved, but rotational and shearing forces are imposed on the valve stem and connectors
Solution Approach 1:
The hydraulic actuator uses pressurized hydraulic fluid acting on a piston to generate linear force directly aligned with the valve stem axis. This eliminates rotational forces entirely since there is no hand wheel or screw mechanism involved. The linear hydraulic force is transmitted directly to the valve stem through a connector, avoiding the rotational and shearing forces that plague mechanical hand wheel systems.
4Force
If hydraulic pressure is varied in the hydraulic sleeve, then high force exceeding 50,000 N is achieved, but system complexity increases
Solution Approach 1:
The hydraulic actuator serves as an intermediary device between the control system and the valve stem. It takes hydraulic fluid pressure as input and converts it to high linear force output on the valve stem. This intermediary mechanism allows the control system to achieve high force (exceeding 50,000 N) without directly applying complex mechanical mechanisms to the valve stem, thereby managing system complexity through functional decomposition.
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 or press system provides a significant force exceeding 50,000 N, enabling safe override or backup operation without torsional or shear forces, ensuring reliable valve control during emergencies or actuator failures.
Implementation Method 1
the hydraulic sleeve being adapted to move the valve stem, the actuator stem, or the stem connector in response to varying hydraulic pressure within the hydraulic sleeve
Implementation Method 2
A hydraulic press is mounted between a control valve and an actuator housing, the hydraulic press being mounted within, and attached to, a yoke that connects the actuator housing to the control valve
Data Source
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.