Sewage pipelines get protection | Infrastructure news

Dynamic Fluid Control has launched the Vent-O-Mat Series RGX II, a second generation air-release and vacuum-break valve designed specifically for sewage pipelines.

The valve controls air release, protects the pipeline against vacuum, and alleviates the effects of potentially damaging surge.

An entirely new product, the design of RGX II incorporates market feedback into proven Vent-O-Mat valve technology, itself the result of decades of comprehensive research.

The RGX II is a brand new valve and not merely an adaptation of an existing one.

It originated from a requirement to overcome the clogging of pipelines in the United States of America caused by grease and fat in the sewer lines.

Internal components comprising solid polyethylene floats and dynamic O-ring seals that do not jam or distort, ensure reliable operation over the life of the valve. Its rugged design eliminates valve failure, breakage, premature closing, incomplete venting and the associated pressure shocks common to other sewage air valves.

On the outside, a short, compact valve body has been achieved without compromising the pressure rating.

Product development took place over a three-year period, the goal being to design a compact valve that would overcome clogging while maintaining a full bore inlet and outlet, and incorporating the integral anti-shock device for which Vent-O-Mat is famous.

The result is the world’s only sewage air release valve with an anti-shock and anti-surge mechanism fitted as standard protection against damage from the high induced pressure transients associated with high velocity air discharge. The mechanism dramatically and automatically reduces the surge caused by liquid column separation and liquid oscillation.

RGX II features full port opening, with large orifice diameters equal to the nominal size of the valve (i.e. a 150 mm valve has a 150 mm orifice). This ensures the highest possible intake of air into a draining pipeline, protecting it against premature mechanical fatigue and pipeline collapse.

Model sizes range from 50 mm to 200 mm.

In operation, the RGX II protects a pipeline under all conditions, irrespective of the state of the water column within it. The valve is biased towards an anti-surge action, allowing controlled air release through an orifice aerodynamically engineered to throttle air discharge when the velocity of the approaching liquid would otherwise become too great and induce an unacceptable pressure rise. This throttling action increases resistance to the flow of the approaching liquid, which decelerates.

The opposite extreme is experienced when a pipeline experiences liquid column separation due to pump stoppage. Under these conditions, RGX II allows air into the pipeline, but throttles its discharge as the separated column begins to rejoin, reducing the impact velocity and alleviating high surge pressures.

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