Axial Flow Valve Toggle Cam for Low-Friction Flow Control
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Solution Overview
Problem
Axial flow valves in the hydrocarbon industry face issues with high frictional forces due to sliding gear mechanisms, leading to low efficiency, increased actuation forces, and potential failure from galling and wear, especially under limited lubrication conditions, while also requiring robust construction for high pressure and temperature applications.
Innovation Solution
A compact and robust axial flow control valve design utilizing a toggle member with actuating surfaces of different radii of curvature, allowing precise control and reduced actuation forces, and enabling a compact construction without increasing flow resistance, by using an elongated crank arm pivotable about a pivot axis with actuating surfaces spaced from the pivot axis, allowing for a smaller toggle member and reduced bulb size.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a sliding rack mechanism is used to convert actuator linear motion to obturator linear motion, then the valve structure is simple, but high frictional forces result in low efficiency and increased actuation forces
Solution Approach 1:
The patent replaces the sliding rack mechanism with a cam mechanism. The cam profile is specifically designed to convert rotational actuator motion directly into linear obturator motion without sliding contact. This substitution eliminates the high frictional losses inherent in sliding gear mechanisms while maintaining the simplicity of the overall structure.
2Volume of moving object
If a sliding rack mechanism is used, then the mechanism is compact, but galling and wear lead to eventual seizure under load cycling
Solution Approach 1:
The cam mechanism replaces the sliding rack and eliminates the sliding contact that causes galling and wear. The cam profile is designed to provide smooth continuous motion without the repetitive sliding and stopping that leads to surface degradation and eventual seizure in sliding mechanisms.
3Reliability
If a toothed rack and pinion system is used to convert perpendicular displacement to axial displacement, then galling failure is less likely, but the system remains sensitive to lubrication and tooth wear
Solution Approach 1:
The patent eliminates the toothed rack and pinion gear train entirely, replacing it with a cam mechanism. This substitution removes the gear teeth that are subject to wear and lubrication sensitivity, while maintaining the ability to convert motion from perpendicular to axial direction through the cam profile geometry.
4Ease of operation
If a crank wheel with connecting rods is used to convert actuator motion to plunger displacement, then motion conversion is achieved, but the system occupies large space and is complicated
Solution Approach 1:
The complex crank wheel and connecting rod system is replaced by a simplified cam mechanism. The cam profile inherently provides the motion conversion function that previously required multiple linkage components, significantly reducing the space occupied by the actuating system while eliminating the complexity of hinged linkages.
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 design achieves efficient and accurate flow control with reduced friction and wear, enabling a compact, robust, and easy-to-assemble valve construction that maintains low flow resistance and minimizes maintenance requirements.
Implementation Method 1
a toggle member (20) pivotably mounted to said bulb (11) so as to be pivotable about a pivot axis (21) between a closing position (Fig. 3) causing said obturator sheath (12) to be in said closed position and an opening position (Fig. 2) causing said obturator sheath (12) to be in said open position
Data Source
Figure 1
Figure 2
Figure 3
AI summary
A valve (1) for controlling a flow of fluid with a bulb (1) suspended in a flow channel section (5), an obturating sheath (12) suspended for axial movement between closed and open positions, an operating member (13) extending axially in the bulb, having an engagement surface (18, 19) facing in axial direction and connected to the obturating sheath, and a toggle member (20) pivotably mounted to the bulb to be pivotable about a pivot axis between a closing position and an opening position causing the obturating sheath to close and open. The toggle member has an actuating surface (22, 23) in contact with the engagement surface in a position in a plane spaced from the pivot axis, which actuating surface has at least first (22a, 23a) and second (22b, 23b) surface portions at mutually different distances from the pivot axis, contiguous to each other and having mutually different radii of curvature about axes of curvature parallel to the pivot axis.