Gas Flow Switch with Dashpot Damping for Low Pressure Detection
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Solution Overview
Problem
Existing gas flow indicators for appliances like gas grills face challenges in detecting low pressure and low flow gas applications, leading to potential safety hazards and inefficiencies, as they often cause pressure loss and flow restriction, and are prone to piston oscillation and calibration issues with varying surface materials.
Innovation Solution
A highly sensitive inline coaxial gas flow switch with a lightweight piston and biasing magnet, combined with a reed switch and optional wireless alarm, designed to detect gas flow without significant pressure loss or flow restriction, and equipped with a dashpot damper to eliminate piston oscillation, allowing for reliable detection and automatic timer activation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional gas flow switch is used to detect gas flow, then gas flow detection is achieved, but pressure loss and flow restriction occur
Solution Approach 1:
The gas flow switch is divided into separate functional components: a piston for flow detection, a reed switch for signal generation, and a dashpot for damping. This segmentation allows each component to perform its function efficiently without creating excessive resistance to gas flow, thereby maintaining reliable detection while minimizing pressure loss.
Solution Approach 2:
A magnet is introduced as an intermediary between the gas flow and the reed switch. The gas flow moves the piston, which carries the magnet, and the magnet's movement triggers the reed switch without requiring direct mechanical contact or high-force mechanisms that would restrict flow. This intermediary approach enables reliable detection with minimal pressure drop.
2Reliability
If a conventional piston mechanism is used in the gas flow switch, then gas flow detection is achieved, but piston oscillation occurs
Solution Approach 1:
A dashpot is introduced as a damping intermediary between the piston and its surroundings. The dashpot provides viscous damping that suppresses piston oscillations without requiring significant force, allowing the piston to stabilize quickly and provide reliable detection signals while maintaining system stability.
3Extent of automation
If upstream valve is used as master cutoff, then automatic shut-off function is achieved, but gas leakage through individual burner valves occurs
Solution Approach 1:
The system incorporates feedback through the reed switch and alarm/timer mechanism. When gas flow is detected, the reed switch activates the alarm or timer, providing feedback to the user to shut off the gas supply. This feedback loop ensures that automatic protection is provided against gas leakage even if the master cutoff valve is not perfectly sealed, by alerting the user to take corrective action.
4Reliability
If temperature sensor is used to detect appliance operation, then operation detection is achieved, but multiple sensors are required for multiple burners
Solution Approach 1:
The gas flow switch serves as a universal detection mechanism for the entire gas appliance system. Instead of requiring separate temperature sensors for each burner, a single gas flow switch detects the presence of gas flow to the appliance, providing operation detection for all burners simultaneously. This multi-functional approach reduces device complexity while maintaining reliable operation detection.
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, low-loss, and low-flow gas detection system that effectively alerts users to turn off gas appliances after a predetermined time, enhancing safety and reducing fuel waste, while being easy to install and maintain, without increasing liability.
Implementation Method 1
When the flow of gas is turned on by one of the grill burner valves, a small differential pressure provides a sufficient lifting force to raise the piston above the outlet ports
Implementation Method 2
The gas flow switch incorporates a reed switch which is activated via a magnet carried in the piston upon sensing the flow of gas
Implementation Method 3
designed with a dashpot dampening mechanism to alleviate any such piston oscillation
Data Source
AI summary
A highly sensitive low loss and low flow fluid flow switch is coupled with an automatic timer and/or optional transmitter to indicate the flow of gas to an appliance and to automatically start a reminder timer to turn the appliance off. After a preset time limit has expired, the timer either sounds an alarm or wirelessly triggers an alarm in a remote location. The receiver portion of the wireless timer may be mounted directly to the appliance (grill handle), so that the timer automatically resets when activity (cover opening or closing) is detected, indicating the appliance is still in use. An alarm can also be configured to sound when the grill is attempted to be ignited with the cover closed, thereby avoiding a potential explosion. A biasing attraction magnet is incorporated in the fluid flow switch to offset either the force of gravity or a return spring in order to extend performance to low pressure and low flow applications. The piston is sealed for use in high pressure/low flow applications, and provided with a vent hole for residual gas bleed-off upon a stoppage of gas flow.