ORVR Valve Assembly Diaphragm Bypass for Tank Pressure Control
Solution Overview
Problem
Existing fuel dispensing systems face issues with vapor control, particularly when vehicles equipped with On-Board Vapor Recovery (ORVR) systems are refueled, as they can lead to over-pressurization of underground storage tanks and potential corrosion due to moisture and debris introduction through air bleed passages.
Innovation Solution
A valve assembly with a stepped passage and diaphragm assembly that bypasses the vacuum assist system when an ORVR-equipped vehicle is being refueled, using an o-ring check valve and plug to prevent vapor draw and allow ambient air entry, minimizing air passages and preventing pump deterioration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a vacuum assist vapor recovery system is used for fuel dispensing, then vapor recovery efficiency is improved, but over-pressurization of underground storage tanks occurs when ORVR-equipped vehicles are refueled
Solution Approach 1:
The valve assembly changes the flow parameters of the vapor recovery system by switching between vacuum assist mode (for non-ORVR vehicles) and bypass mode (for ORVR vehicles). The diaphragm responds to pressure differential changes to automatically adjust the valve position, thereby changing system operating parameters to match vehicle type and prevent over-pressurization
Solution Approach 2:
The valve assembly acts as an intermediary device between the vacuum assist vapor recovery system and the fuel dispensing nozzle. It mediates the vapor flow by either allowing vacuum-assisted vapor recovery or bypassing the vacuum system entirely when ORVR vehicles are detected, thus protecting the underground storage tank from over-pressurization
2Adaptability or versatility
If air bleed passages are provided in the valve assembly, then system operation flexibility is improved, but moisture and debris introduction causes corrosion and deterioration
Solution Approach 1:
The diaphragm assembly uses a flexible thin film to seal the valve interior from the external environment. This flexible membrane allows pressure differential detection and valve actuation while preventing moisture and debris from entering the passage through which the valve stem moves, thus eliminating corrosion risks while maintaining operational flexibility
3Device complexity
If a shiftable valve assembly moves within the same passage that functions as the air bleed passage, then device simplicity is improved, but valve assembly corrosion occurs due to moisture and debris exposure
Solution Approach 1:
The valve assembly is segmented into two distinct functional zones: an internal passage for vapor flow and valve movement, and an external air bleed passage. The diaphragm creates a seal that divides these spaces, allowing the valve stem to shift within the protected internal passage while the external passage handles air bleeding. This segmentation protects the valve assembly from corrosion while maintaining structural simplicity
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 manages vapor recovery, prevents over-pressurization of underground storage tanks, and reduces the risk of pump deterioration by allowing ambient air to vent into the vapor recovery line, ensuring efficient and reliable fuel dispensing for vehicles with and without ORVR systems.
Implementation Method 1
the combination of the vacuum from the vacuum assist system, and the ORVR vacuum draw, has a tendency to pull the diaphragm of the valve design upwardly
Implementation Method 2
the o-ring check valve provided upwardly upon stem is lifted, and allows ambient air to enter into that location, pass along the valve stem, and pass into the downstream conduit
Data Source
AI summary
An ORVR valve assembly operative of relatively few movable components includes a valve body, having conduits to provide for routine passage of vapors therethrough through operations of a vacuum assist system. This is when a non-ORVR vehicle is being replenished with fuel. But, when a vehicle equipped with ORVR vapor recovery is being fueled, vacuum is generated above a piston supported diaphragm, attracts the diaphragm upwardly, plugs off the vapor passage conduits, and allows the ORVR system of the automobile to exclusively treat the generated vapors at the location of the vehicle and its fuel tank. Simultaneously, air is vented into the valve body, below its diaphragm, and into the vapor return line of the vacuum assist system, to prevent it from being subject to excessive vacuuming. Thus, vapor recovery or treatment can be achieved through the use of the ORVR valve assembly of this invention, regardless whether the automobile being refueled is an ORVR equipped vehicle, or one that is not equipped with vapor recovery.