A roadside compressor delivering air to an air treatment unit, which is then injected into the pipe for scouring. These mobile units incorporate aftercoolers, filtration systems, pressure regulators and hoses to supply air suitable for air scouring water mains. Pressure can be regulated not to exceed the normal working pressure of the existing mains. It is manufactured in accordance with the specification of the Water Research Council to deliver filtered air which meets the air quality standard BS EN12021. The PS125 has a capacity of 125cfm at 7 bar and the PS250 has a capacity of 250cfm at 7 bar.
Air Scouring of water mains is an extremely effective ‘non-aggressive method of cleaning water mains. From 75mm diameter to 300mm diameter, with typical cleaning lengths ranging from 100 to 1000 metres.
Air scouring works by using filtered ‘oil free’ compressed air, injected into the mains via a hydrant to propel a small volume of water at high velocity. Air and water are ejected together with any suspended solids from a hydrant at the end of the length being cleaned. This system has the effect of achieving water velocities high enough to carry deposits in the water stream.
Provided that a continuous supply of compressed air and water is in the right proportions, discrete slugs of water are formed in the main and are driven along at high velocity by the compressed air. It is the slug flow system that enables solids to remain suspended in the water over the long distances being cleaned.