Backpacking Stove Tip Valve with Tapered Bore for Automatic Reset
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Solution Overview
Problem
Traditional backpacking stove tip valves often impede gas flow when the stove is upright, fail to reliably shut off gas when tipped over, and require a pin to reset, leading to user frustration and potential stove malfunction.
Innovation Solution
A tip valve with a tapered bore housing a ball bearing and actuator pin, allowing automatic reset by gravity when the stove is returned to a vertical position, eliminating the need for a pin and ensuring reliable gas shut-off and reactivation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a constant diameter bore is used in the tip valve, then the ball bearing can roll freely to shut off gas flow when tipped over, but the fuel flow around the ball bearing is impeded when the stove is upright
Solution Approach 1:
The bore diameter is varied along its length, being larger at the upright position to allow free fuel flow and smaller at the tipped position to ensure reliable ball bearing seating and gas shut-off. This local variation in geometry resolves the contradiction between maintaining fuel flow during normal operation and ensuring reliable shut-off when tipped.
2Productivity
If the bore diameter is significantly greater than the ball bearing diameter to avoid impeding fuel flow, then fuel flow is maintained, but the ball bearing cannot reliably seat against the o-ring seal when tipped over
Solution Approach 1:
The bore is designed with different diameters at different locations: a larger diameter portion allows the ball bearing to roll freely and maintain fuel flow during upright operation, while a smaller diameter portion ensures the ball bearing seats completely against the o-ring seal when tipped, achieving reliable gas shut-off.
3Reliability
If a pin is used to reset the ball bearing to the bottom of the bore after tipping, then the tip valve can be reset, but the device complexity increases and user operation becomes more difficult
Solution Approach 1:
The tapered bore design allows the ball bearing to automatically return to its normal position at the bottom of the bore when the stove is uprighted, eliminating the need for a separate reset pin or mechanism. The geometry itself provides the resetting function, reducing device complexity and improving ease of operation.
4Productivity
If the ball bearing is held at the bottom of the bore by gravity when upright, then gas flows freely to the burner, but when tipped the ball bearing may not advance far enough to completely seat against the o-ring seal
Solution Approach 1:
The bore diameter is reduced at the tipped position to create a seating zone that ensures complete contact between the ball bearing and the o-ring seal. This localized geometry change guarantees reliable shut-off while maintaining adequate flow during normal upright operation.
Solution Approach 2:
The bore is designed with asymmetric geometry where the diameter varies along its length, creating different flow characteristics and ball bearing interaction at different orientations. This asymmetry ensures proper function in both upright and tipped positions.
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 seamless gas control and automatic reset without user intervention, preventing accidental gas flow and stove malfunction, enhancing user experience and stove reliability.
Implementation Method 1
When in a vertical orientation, the ball bearing is held at the bottom of the bore by gravity
Implementation Method 2
The ball bearing is then intended to seat against an o-ring seal and be held in place by the gas pressure in the bore upstream of the ball bearing
Implementation Method 3
The tip valve includes a tip seal and a ball bearing housed within a tapered bore
Implementation Method 4
an actuator pin configured to push against the ball bearing to dislodge the ball bearing from the tip seal
Data Source
AI summary
A tip valve and a cook system incorporating same that automatically stops the flow of gas to a burner when tipped over and that automatically resets when disconnected from the fuel canister to allow the flow of gas to resume when righted and reconnected are provided. The tip valve includes a ball bearing freely moveable between a fuel canister actuator pin and a tip seal within a bore having two different diameters at each end thereof. The transition between the two diameters forms a taper that may be continuous forming a smooth tapered bore, or discontinuous formed by at least one counter bore. The automatic resetting is provided without the use of a mechanical pin or member.