Overfill Prevention Valve with Float-Cam Actuation
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Solution Overview
Problem
Existing devices for preventing overfilling of liquefied gas cylinders face issues such as wear and tear, reduced reliability, difficulty in creating a vacuum, reduced gas exit capacity, sensitivity to inclination and oscillations, and sluggish response due to membrane valves or complex spherical valve mechanisms.
Innovation Solution
A device with a valve featuring a rigid truncated cone closure means, a guide element, and a control rod system, where a float and cam mechanism ensure quick and reliable closure of the valve at maximum fill level without relying on membrane deformation or spherical components, allowing for efficient gas flow and vacuum creation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If membrane valves are used for preventing overfilling, then the valve can be normally closed and control gas flow, but the device experiences greater wear and tear and lesser reliability
Solution Approach 1:
The patent removes the membrane component from the valve system entirely. Instead of using a membrane that deforms to control flow, the invention employs a rigid spherical closure element that is actuated by a float-cam mechanism. This extraction of the membrane eliminates the wear and reliability issues associated with flexible membrane deformation while maintaining the overfill prevention function.
Solution Approach 2:
The patent inverts the normal valve operation concept. Rather than a normally closed valve that opens under pressure (membrane valve), the system uses a normally open spherical closure that is actively closed by a mechanical actuation mechanism when the float rises. This inversion allows for more reliable rigid component interaction without the wear problems of membrane-based systems.
2Productivity
If membrane valves are used for preventing overfilling, then gas flow can be controlled, but it becomes difficult to produce a vacuum inside the container
Solution Approach 1:
By removing the membrane component entirely and replacing it with a rigid spherical closure element actuated by a mechanical linkage, the valve can be freely opened or closed without the restrictions imposed by membrane flexibility. This enables both effective gas flow control during filling and easy creation of vacuum conditions when needed, as the rigid sphere can be reliably positioned to fully open the flow path.
3Extent of automation
If spherical member rotation mechanism is used, then the valve can be actuated by float movement, but the system becomes sensitive to inclination and oscillations of the cylinder
Solution Approach 1:
The patent segments the actuation mechanism into distinct functional components: a float that moves vertically with liquid level, a cam mechanism that converts vertical float motion into horizontal rod displacement, and a rigid spherical closure. This segmentation allows the float to be isolated from inclination effects while the cam mechanism provides stable geometric conversion of motion, eliminating sensitivity to cylinder orientation.
Solution Approach 2:
The invention changes the dimension of actuation from rotational (spherical member rotation) to linear (rigid rod displacement). The float moves vertically in one dimension, the cam mechanism translates this to horizontal rod movement in another dimension, and the spherical closure moves linearly to open or close the valve. This dimensional transformation eliminates sensitivity to inclination and oscillations.
4Extent of automation
If spherical member rotation mechanism is used, then the valve can be actuated, but the system exhibits sluggish speed response after maximum fill level is reached
Solution Approach 1:
By segmenting the actuation mechanism into a float, cam, and rigid rod, the system achieves direct and immediate transmission of motion. When the float reaches the cam's actuation point, the rigid rod instantly displaces the spherical closure to close the valve. This segmented mechanical linkage eliminates the sluggish response associated with spherical member rotation, providing rapid and decisive valve closure.
5Extent of automation
If complex spherical valve mechanism with multiple elements is used, then the valve can be actuated by float, but the construction and assembly become complicated and sensitive to size tolerances
Solution Approach 1:
The patent extracts and removes the complex spherical member rotation mechanism entirely. Instead, it employs a simplified system with a float, cam mechanism, and rigid spherical closure element on a linear rod. This extraction eliminates the need for precise spherical coupling and reduces the number of elements, making construction and assembly much simpler and less sensitive to tolerances while maintaining automatic actuation functionality.
6Productivity
If membrane valves are used, then the valve can control gas flow, but the capacity of exiting gas during normal use is reduced
Solution Approach 1:
By removing the membrane and replacing it with a rigid spherical closure element, the valve opening can be made larger and the flow path more direct. The rigid sphere can be positioned to provide a wide open passage during normal gas exit, maximizing the capacity for gas flow while still providing reliable closure when activated by the float-cam mechanism.
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 solution provides a reliable, efficient, and simple mechanism for preventing overfilling, maintaining consistent performance regardless of pressure or fluid density, improving repeatability and reducing wear, while allowing better vacuum creation and gas exit capacity.
Implementation Method 1
a cam mechanism (21) to exert said thrusting force (F)
Implementation Method 2
a rigid closure means (7) having the shape of a truncated cone... axially movable in said valve body (3) from and toward a valve seat (8) in order to respectively open and intercept said gas duct (5)
Data Source
AI summary
A device for preventing overfilling of containers, such as those intended to contain liquefied gases, includes a valve body in which a gas duct is defined and a closure. The closure is axially movable in the valve body away from and towards a valve seat in order to respectively open and shut off the gas duct. An actuator, capable of exerting a thrust, urges the closure away from the seat. The actuator includes a float, a cam mechanism and a lever mechanism. The cam mechanism exerts the thrust in an ascending phase of the float until a preimposed limit position corresponding to a maximum filling level is reached. The lever mechanism exerts the thrust in at least a first part of a descending phase of the float starting from the limit position.