Aluminum Alloy Fuel Tank Overfill Prevention Valve (OPV)
The Aluminum Alloy Overfill Prevention Valve (OPV) is a crucial safety device engineered to prevent hazardous liquid spills during the pressurized filling of fuel storage tanks (both Aboveground Storage Tanks – AST and Underground Storage Tanks – UST). Utilizing a robust mechanical float system, this valve ensures compliance with environmental and safety regulations (UL2583, NFPA 30, etc.) by automatically interrupting flow when the fuel level reaches a pre-set maximum.
⚙️ Product Features and Specifications
| Parameter | Detail | Compliance & Safety Benefit |
| Body Construction | Passivated Aluminum Alloy | Lightweight, highly corrosion-resistant, and suitable for petroleum products (Diesel, Biodiesel, Fuel Oil). |
| Mechanism | Mechanical Float System (Float & Piston) | Requires no external power; reliable, automatic shut-off. |
| Shutoff Level | Field Adjustable (Typically 90-95% Capacity) | Allows precise setting to meet local regulatory fill requirements. |
| Typical Sizes | 2” to 6” (e.g., 2” or 3” NPT connections) | Standard sizes for tank fill risers. |
| Sealing / Internals | Polypropylene Float, Stainless Steel/Aluminum Rods | Materials compatible with common fuels. |
| Filling Type | Pressurized Tight Fill | Designed for pump-in deliveries; will not function in gravity fill applications unless specifically rated. |
| Safety Feature | Built-in Bleed/Anti-Siphon Hole | Relieves fill hose pressure after shutoff, alerts the operator, and provides anti-siphon protection. |
| Code Compliance | UL Listed, Meets NFPA 30/30A requirements (Varies by specific model) | Essential for regulatory approval and insurance requirements. |
💡 Operating Principle
Installation: The OPV is installed inside the tank, threaded onto the fill pipe riser, often secured within the spill containment basin. The float rod extends downward into the tank.
Filling: During pressurized delivery, the fuel flows through the open valve into the tank.
Warning/Shutoff: As the liquid level approaches the pre-set limit (e.g., 90% full), the float rises, mechanically activating the valve piston.
Initial Closure: The valve restricts the flow significantly (a “kick” in the delivery hose often occurs).
Final Closure: If the delivery continues past the warning point, the valve fully closes, stopping the flow of fuel (less than 2% of max flow remains for pressure relief).
Pressure Relief: The small bleed hole allows the trapped pressure in the fill hose to dissipate slowly into the tank, alerting the operator to disconnect the filling equipment and preventing environmental release.
🎯 Applications
The Aluminum Alloy OPV is critical for all facilities storing flammable or combustible liquids:
Retail Service Stations (UST)
Commercial/Industrial Fuel Oil Systems (AST)
Mission-Critical Backup Generator Fuel Tanks
Diesel, Biodiesel, and Heating Oil Storage
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