SU806071A1 - Method of producing filter - Google Patents

Description

(54) METHOD OF MANUFACTURING A FILTER

I

The invention relates to a filter manufacturing technique for drainage of ameliorative, hydraulic and road construction, as well as for the purification of gases and liquids.

A known method of making filters consists in mixing powdered polyethylene with an inert filler heated to 250-300 ° C, followed by packing the hot mass into molds or. drainage 1.

However, this method does not allow the manufacture of tubular filter elements.

There is also known a method for producing filters by mixing wood waste (sawdust) with a thermoplastic powder, followed by laying the mixture into molds, heating it to the melting temperature of the thermoplastic, cooling it and removing the filters from the molds 2.

The disadvantage of the method is that, due to the low thermal conductivity of the wood, it is difficult to manufacture thick-walled filters, accompanied by uneven fusion of the thermoplastic powder through the thickness of the filter and a decrease in its physical and mechanical properties.

as well as by burning the filter and slowing down the process of its manufacture.

The purpose of the invention is to accelerate the process of making a filter and increasing its physical and mechanical properties.

Claims (2)

This is achieved by adding heat-conducting granular filler (sand, crushed stone, gravel, etc.) to the crushed wood. . The crushed wood (sawdust) is mixed with heat-conducting napole1 in the proportion OT-J: 0.5 to 1; 10 or from 10 to 60% by volume, i.e. from 0.5 to 10 volume is added to one volume part of the heat-conducting filler. parts of wood waste. The resulting mixture is moistened to such an extent that free water is contained in the ke mixture, then a thermoplastic powder, for example, tylen or polystyrene, is added and mixed. The need for a thermoplastic powder is dictated by the strength characteristics of the filter and is 50-1-75 kg of polyethylene or 100--300 kg of full styrene foam per 1 m of a mixture of fillers (sawdust + sand). The resulting mixture is placed in a mold and compacted with 8 pressure in the range of 1-2 kgf / cm. The mold filled with the mixture is placed in a heat chamber and held until the thermo-part powder is completely melted at an optimum temperature of 160-180 ° C for polystyrene and 170-220 ° C for polyether for 0.5-4 hours, depending on the size of the filter to be molded. Then the mold is placed in a cooling chamber and cooled with cold air to + 100-120 ° C and then cooled with cold water to + 3050 ° C. After cooling, the mold is disassembled, the finished filter is removed from it. The working surfaces of the mold, before putting the mixture into it, are coated with an anti-adhesive agent, for example, an aqueous solution of chalk and silicate glue (five volume parts of water, one part of chalk and one part of silicate glue), and dried. Example. Take one volume part of the coarse sand and one volume part sawdust and shift. Water is then added for surface wetting of the filler and mixed, then the thermoplastic powder is added in a ratio of 1: 1.5 by volume, i.e. one and a half parts of the filler (sawdust + sand) are added to one part of the thermoplastic powder and mixed. The resulting mixture is poured into a metal mold and compacted with its pressure in the range of 1-2 kgf / cm. The mold is placed in a heat chamber and kept in a chamber at optimum temperatures of 160-180 ° C, at which the melting of thermoplastic powder (polystyrene) occurs and. adhesion to filler grains. The mold is held in a heat chamber until the thermoplastic powder is completely melted across the entire thickness of the molded filter. The holding time of the mold in the heat chamber depends on the wall thickness of the forming filter and is 0.5 hours for a wall thickness of 10 mm, 3.5-4 hours for a wall thickness of 80 mm. Then the mold, without subjecting it to jolts and strokes, is placed in a cooling chamber, where it is cooled to 100-120 ° C, and then cooled with cold water to 3050 C. Then the mold is disassembled, removing the finished filter. . The compressive strength of the filter varies within wide limits, depending on the content of the thermoplastic and the heat-conducting filler, and ranges from 50 to 140 kgf / cm. The invention allows to produce thick-walled filters of uniform structure with high physicomechanical properties. Claim method The method of making a filter involves mixing moistened wood waste with a thermoplastic powder followed by laying the mixture into molds, heating it to complete melting of the thermoplastic powder, cooling and stripping, characterized in that it accelerates the process of making the filter and enhances its physical-mechanical properties. properties, heat-conducting granular filler is added to wood waste. Sources of information taken into account in the examination 1. Authors svdedelstvo USSR № 244198, cl. E 02 at 11/00, 1% 7. 2. Author's testimony of the USSR K 391152, cl. From 04/43/12, 1971.