Multi-Function Variable-Orifice Air Valve

The Multi-Function Variable-Orifice Air Valve is Redstar Valve’s new-generation patented product. As an advanced, self-adjusting multi-functional air valve, it integrates the following five core capabilities:

1. High-Speed Exhausting with Variable Flow Rate
During the initial water-filling phase of empty pipelines, the valve enables high-capacity air discharge. The exhaust flow rate adjusts dynamically from large to small; as the exhaust pressure gradually rises, the discharge channel automatically restricts from 100% DN (full bore) down to approximately 5% DN.

2. Intelligent Water-Filling Control & Water Hammer Prevention
As the internal pressure increases during pipeline filling, the valve automatically adjusts and reduces the cross-sectional area of the exhaust channel. This provides safe, highly efficient control over the water-filling process, preventing the air valve from slamming shut prematurely at the final stage of filling and completely eliminating large-orifice closure water hammer.

3. Automatic Micro-Air Release
During normal pipeline operation, the valve continuously and automatically expels micro-quantities of dissolved air released from the water. This minimizes fluid resistance and significantly enhances water transmission efficiency.

4. Rapid Large-Orifice Air Intake under Negative Pressure
When a pipeline is being drained or encounters transient negative pressure, the large orifice opens instantly to draw in air. The response time to transient negative pressure reaches an exceptional 0.5 seconds at -2 kPa, effectively safeguarding the pipeline against vacuum collapse.

5. Water Column Separation & Reclosure Cushioning
During transient events, when the internal pipeline pressure shifts from a transient negative pressure to a transient positive pressure (during water column reclosure), the exhaust channel gradually constricts as the pressure differential increases—narrowing to approximately 5% of the full bore. This mechanism instantaneously traps a calculated air pocket to cushion the moving water column, drastically mitigating reclosure water hammer.