Granular plastics packing filter for tubular well - has domed cavities in packing at perforations preventing turbulence

摘要

The filter for tubular well consists of granular material packed around perforated tube in ground. A domed cavity projecting into packing is arranged at each performation. The presence of dome prevents turbulence of water entering the tube which cause incrustation of the perforations. A domed cavity has - in the filter tube circumferential direction - the same dimensions as its associated perforation. The ground water enters tube almost without resistance through this cavity. The domed shape ensures good static strength of the packing against radial forces. The packing consists of plastics material granules.