Valve Actuator Assembly With Planetary Gearing for Safer Reset Torque
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Solution Overview
Problem
Large operating slam-shut valves require significant manual torque to reset, which can be dangerous and cumbersome, especially when the handle is reversed, due to the need for increased lever arm length and weight.
Innovation Solution
An actuator assembly incorporating a Scotch yoke mechanism and planetary gear transmission mechanism that amplifies rotational velocity to facilitate translational movement of the valve stem, reducing the required manual torque and enhancing safety by providing a spring-release mechanism for automatic disengagement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If the lever arm of the handle is increased to meet the torque requirements for resetting large operating valves, then the required manual torque is sufficient, but the weight of the lever increases and it may be dangerous to an operator if the handle is reversed
Solution Approach 1:
The patent replaces the direct mechanical lever system with a Scotch yoke mechanism coupled to a planetary gear transmission. The Scotch yoke converts rotational motion from a compact handle into linear reciprocating motion of the valve stem, while the planetary gear system provides torque multiplication. This substitution eliminates the need for a long, heavy lever arm, allowing sufficient torque to be generated with a compact, safe handle design.
2Force
If a long lever arm is used to provide sufficient torque for resetting the valve, then the torque requirement is met, but the device complexity and weight increase
Solution Approach 1:
The patent substitutes the simple but bulky long lever arm with a complex yet compact mechanism consisting of a Scotch yoke and planetary gear transmission. The Scotch yoke mechanism converts rotational motion into linear motion efficiently, while the planetary gear system provides high torque multiplication in a compact package, reducing overall device complexity and weight compared to an extended lever arm.
Solution Approach 2:
The planetary gear transmission mechanism employs a nested structure where satellite gears orbit around a central sun gear, with multiple gear stages contained within a compact housing. This nesting arrangement allows for high torque multiplication without increasing the external dimensions of the handle assembly, maintaining compactness while providing sufficient resetting torque.
3Ease of operation
If manual torque is increased to reset the valve, then the valve can be opened, but the operation becomes cumbersome and dangerous
Solution Approach 1:
The patent replaces the need for high manual effort with an automated mechanical assistance system. The Scotch yoke mechanism, when actuated by a compact handle, generates sufficient force through its mechanical advantage and the planetary gear torque multiplication to easily reset the valve, making the operation simple and safe without requiring the operator to exert excessive force.
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 actuator assembly significantly reduces the manual effort needed to reset the valve, ensuring safer operation by multiplying input torque into higher output torque, and includes a spring-release mechanism for automatic disengagement to prevent injury and maintain valve functionality.
Implementation Method 1
a planetary gear transmission mechanism that amplifies rotational velocity to facilitate translational movement of the valve stem
Implementation Method 2
The actuator assembly significantly reduces the manual effort needed to reset the valve, ensuring safer operation by multiplying input torque into higher output torque
Implementation Method 3
A Scotch yoke mechanism may be operatively coupled to the stem and the transmission mechanism via the second end of shaft. The Scotch yoke mechanism may be configured to receive the second rotational velocity and cause movement of the stem and the control element along the first axis in a translational direction
Implementation Method 4
includes a spring-release mechanism for automatic disengagement to prevent injury and maintain valve functionality
Data Source
AI summary
A fluid control device comprising including a body having an inlet, an outlet, and a fluid flow path between the inlet and the outlet, a seat, and a control element that is coupled to a stem. The control element and the stem are movable relative to a longitudinal axis and biased toward a closed position, in which the control element engages the seat. An actuator assembly is operatively coupled to the stem and includes a planetary gear transmission mechanism configured to receive a first rotational velocity and to deliver a second rotational velocity different than the first rotational velocity. A shaft has a first end coupled to the transmission mechanism and a second end coupled to valve stem. The second rotational velocity is transmitted to the valve stem to move the control element between the closed position and an open position.