Fuel Nozzle Attitude Sensing with Rolling Element Shutoff
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Solution Overview
Problem
Current fuel dispenser nozzles experience unintended valve shutoffs due to overly sensitive or faulty attitude sensing devices, leading to nuisance trips when the nozzle is angled at or above horizontal, which results in unnecessary fuel flow interruptions.
Innovation Solution
A fuel dispensing nozzle with an attitude sensing arrangement featuring a non-cylindrical chamber and a movable element, such as a spherical ball, that engages a shutoff port when the nozzle is raised above horizontal, utilizing gravitational and suction forces to block the vacuum sensing path and trigger the shutoff mechanism, thereby preventing unnecessary shut-offs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If an attitude sensing device is made highly sensitive to detect when the nozzle is angled at or above horizontal, then the shutoff mechanism is triggered reliably to prevent fuel spillage, but unintended nuisance trips occur frequently causing unnecessary fuel flow interruptions
Solution Approach 1:
A rolling element (ball) is introduced as an intermediary mechanical component between the attitude sensing function and the shutoff mechanism. The ball rolls within a non-cylindrical chamber along a tapered surface in response to nozzle angle changes, mechanically mediating the transition between sensing and actuation. This intermediary mechanism filters out minor vibrations and transient angle changes that would otherwise cause nuisance trips, while still reliably triggering shutoff when the nozzle is truly removed from the tank.
Solution Approach 2:
The system transitions from a static or directly-actuated sensing mechanism to a dynamic rolling element system. The ball's motion along the tapered surface creates a dynamic response that inherently dampens rapid or minor angle changes. The rolling motion requires sustained angular displacement to overcome inertia and friction, thereby distinguishing between temporary disturbances and genuine removal events, improving reliability without causing productivity loss.
2Productivity
If the attitude sensing device is made less sensitive to reduce nuisance trips, then fuel dispensing continuity is maintained, but the shutoff mechanism may fail to trigger when the nozzle is actually removed from the tank
Solution Approach 1:
The chamber is designed with a non-cylindrical, asymmetric cross-section featuring a tapered surface that creates directional sensitivity. The asymmetric geometry ensures the rolling element responds differently to angle changes in the removal direction versus normal dispensing movements. This asymmetry amplifies the mechanical response to genuine removal events while maintaining stability during normal operation, achieving both productivity and reliability.
Solution Approach 2:
The system changes the physical state and motion parameters of the sensing element based on nozzle angle. As the nozzle angle changes from vertical (dispensing) to horizontal or upward (removal), the gravitational component along the tapered surface changes, altering the ball's position and motion characteristics. This parameter change approach allows the system to distinguish between different operational states reliably without excessive sensitivity.
3Device complexity
If a traditional attitude sensing device is used, then the structure is simple, but the device is overly sensitive or faulty causing unintended valve shutoffs
Solution Approach 1:
The rolling element system is self-regulating and self-filtering. The mechanical design of the non-cylindrical chamber and tapered surface allows the ball to automatically find its equilibrium position based on nozzle angle, without requiring external calibration or adjustment. The system's own inertial and friction characteristics provide natural filtering of noise and transient disturbances, achieving high reliability through self-service mechanisms rather than complex electronic sensing and filtering circuits.
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 effectively minimizes unintended nuisance trips by ensuring reliable and predictable shutoffs only when the nozzle is removed from the tank, reducing fuel spillage and improving operational efficiency.
Implementation Method 1
the rolling element rolls toward the shutoff port when the nozzle is held at an angle at or above horizontal
Implementation Method 2
a vacuum sensing path configured to have a negative pressure when fuel is flowing through the dispensing path
Implementation Method 3
raising the nozzle to an angle sufficient to allow gravitational and suction forces to cause the rolling element to roll toward and engage the valve seat
Data Source
AI summary
An attitude sensing arrangement for triggering a shutoff mechanism on a fuel dispensing nozzle comprising a rolling element placed inside a non-cylindrical chamber that is sealed with a plug such that the rolling element may move freely inside the chamber. A vacuum sensing path passes from a sensing port in the nozzle spout, through a vacuum sensing tube, into the non-cylindrical chamber, and into a venturi-generated vacuum chamber. The attitude sensing arrangement is configured such that the rolling element blocks a shutoff port in the non-cylindrical chamber when the nozzle is raised past a certain shutoff angle. When the vacuum sensing path is blocked by the rolling element in this manner, the shutoff mechanism closes the main fuel valve.