The Preliminary Experimental Study On Improving Gravel-pasted Filter

Gravel-pasted filters are usually useded as the head of filter in small and medium-sized underground intake project, and it has advantage of light weight, easy transportation a ,high degree of mechanization and uneasy of corrosion,the water filtered by which is also able to meet the basic drinking water standards.At present, the gravel-pasted filter are widely used in the water supply, precipitation, drainage, hydrological observation, geothermal mining and the repair of sand gushing tube-wells, which fully demonstrates the superiority of it, However,it's not used in filter water projects of surface water. Thus,the study on whether gravel-pasted filter can applied directly to surface water filter or tthe air-conditioning heat pump water technology hrough the improvement have an important significance of theory and practice.This article has studied the performance of the improved filter buried in sand and stone on the basis of fully understanding the relevance characteristic of gravel-pasted filters and the laboratory test research of the filter performance of two bistratal gravel-pasted filter to the waters with different types of quality,In this paper, outdoor and indoor pilot study combining is used as well as the combing of qualitative and quantitative analysis which get understanding and conclusions about improving filtering performance and research and the results of their research ,it have a certain theoretical value and practical significance in science and further improving the study of gravel-pasted filters.(1) Through the preliminary experimental study on gravel-pasted filter, analysed two double-decker (3~5mm/1.5~2.5mm and 1.5~2.5mm/0.5~1.5mm) gravel-pasted filter,s the net situation under the conditions of different water quality That when affixed directly under gravel-pasted filter the water quality of the soil particles can not filter the fundamental role, mainly due to their own gravel-pasted filter caused by the fixed structure.(2) Through two double-decker (3~5mm/1.5~2.5mm and 1.5~2.5mm/0.5~1.5mm) gravel-pasted filter,s hydrometry at different water quality and sand, analyse the gravel-pasted filter,sfiltering mechanism that filters gravel-pasted filter is the filtering mechanism of the main roles: that is, the larger particles in the water can not pass through the porous media or porous media are able to embed, but the filter can not be filtered in the filter of outside..(3) Established the theoretical relationship between gravel-pasted filter,s particle size and its size through the material.(4) Using the sand filtration,s characteristic and gravel layer affixed to the supporting role, will be posted on gravel filter layer buried in sand stone, gravel paste made of improved filter device. The best water in the backwash operating parameters under the condition that the intensity of flushing 6L / s ? m2, flushing time for 2min, washed for 3 times the number (the first wash for the 30s, the second wash for 60s, for the third wash 30s); Through the single-grit, single-layer of sand, fine sand of single-layer, double-thick in the sand, double in and double-coarse sand, fine sand this experiment six different turbidity in the water under the conditions of and the turbidity test. The use of double-layer filter is more effective than the use of single-layer filter media better. The result shows that it is feasible that using sand as a filtering layer and gravel-pasted filter as tub bearing the weight filter the surface water, applicable to surface water of the primary filter.