The HX8/HXF8 single intake valve with nozzle (flame arrestor) is a one-way vacuum-breaker breather valve installed on the top of fixed roof tanks, specifically designed for vacuum intake protection. This valve features an external piping connection (with nozzle). When the tank vacuum exceeds the set value, the vacuum disc automatically opens to introduce blanketing gas (such as nitrogen) or air through the nozzle, rapidly restoring tank pressure; the valve closes tightly when normal pressure returns. An optional built-in flame arrestor prevents external flame propagation. Its core purpose is to automatically and controllably admit gas during tank discharging, emptying, or sudden temperature drops to prevent tank collapse or deformation, while avoiding direct intake of moist air or contaminants. It is suitable for vacuum-sensitive tanks requiring centralized gas supply.

HX8 and HXF8 flame arrester single intake valves with pipe connection product diagram

1. One-way intake function: Only the vacuum disc operates, automatically opening to admit gas when vacuum exceeds set point, without overpressure relief; suitable for tanks with independent pressure relief devices.

2. Nozzle design: Standard flange or threaded connection for piping to a nitrogen supply or air filter, enabling centralized and controlled gas intake.

3. Set-pressure operation with reliable sealing: Flat or tapered hard seal provides stable vacuum opening and zero leakage when closed.

4. Optional built-in flame arrestor: Can be equipped with stainless steel corrugated plate flame arrestor core to prevent external flame ingress through the intake passage.

5. Large ventilation capacity with low pressure drop: Optimized flow path ensures low intake resistance, meeting instantaneous high-volume gas demand during rapid discharging.

6. All-weather protection structure: Rain and dust cover with internal drainage prevents water accumulation, suitable for harsh outdoor environments.

7. Corrosion-resistant materials: Body available in aluminum alloy, cast steel, or stainless steel; disc and internal parts in stainless steel for various corrosive media.

8. Easy maintenance: Removable disc assembly; flame arrestor core (if equipped) can be extracted for cleaning; standard nozzle interface for easy connection.

Structural diagram of HX8 and HXF8 flame arrester single intake valves with pipe connection

Drawing of Parts

Performance Specification Table

Ventilation Capacity Table

Operating Pressure

HX8 type with connecting pipe suction valve DN50-250             HXF8 type with connecting pipe flame retardant

Outline dimension table

suction valve DN50-2