Technology and apparatus for forming worm channel with plastic liner of centrifugal pump

Abstract

A technology for machining the worm-shaped channel with plastic liner for centrifugal pump includes such steps as die pressing a plastic liner with a certain thickness onto the the metallic worm of centrifugal pump, and milling according to designed template of said channel. Its advantages include high efficiency and flexibility, and low cost.

Description

technical field [0001] The invention relates to the improvement of the plastic-lined centrifugal pump, in particular to the molding of the plastic-lined flow channel of the centrifugal pump. Background technique [0002] In order to solve the transportation of corrosive and granular media, an economical and effective way is to use steel-lined plastic centrifugal pumps, that is, to compound a layer of corrosion-resistant and wear-resistant plastic layer with a certain thickness on the lining of the metal pump body of the centrifugal pump. , such as ultra-high molecular weight polyethylene. However, due to the low fluidity of plastics with corrosion-resistant and wear-resistant properties, usually only the molded lining method can be used, and at present, for lining such plastics, in order to facilitate demoulding and obtain a lining layer with higher density and certain thickness, use The metal pump body of the centrifugal pump is used as the outer mold, and the inner plasti...

AI Technical Summary

Problems solved by technology

However, the flow path with a circular track will cause the efficiency and hydraulic characteristics of the centrifugal pump to decrease, and this decrease is more obvious especially in small flow and high pressure centrifugal pumps.

In order to overcome the defect that the molded lining cannot obtain the ideal volute track flow channel, Chinese patent 86100758 discloses a method and mold for molding the lining by using a parting block mold. The flow channel is designed and a number of combinable and disassembled volute blocks and mandrel combined molds are used as the lining mold, which are formed by heating and unidirectional extrusion, so that a lining plastic layer with a volute flow channel is obtained between the inner and outer molds

This lining method, first, the production efficiency is low; second, due to the complex flow path of the volute of the pump body, the density of the unidirectional extrusion lining layer is low, which is easy to cause shrinkage, which reduces the anti-corrosion and wear resistance, and it is difficult to obtain Uniform and dense overall lining layer, especially in larger pumps, this defect is more obvious

In order to overcome the above deficiencies, Chinese patent 96117172 has made improvements to it, disclosing a lining method and mold using bidirectional extrusion molding, but only partially overcomes the defects of low density and unevenness of the lining layer, and the production efficiency has not been improved. improve

In addition, the above-mentioned direct lining method and mold with a volute flow channel not only have low production efficiency and high cost; moreover, the assembly and disassembly process is cumbersome, and the mold clamping pressure required is high, and the mold, especially the outer mold of the pump casing, is easily damaged.

Then there is the direct molding of the lining spiral channel, which can only be lined with ultra-high molecular weight polyethylene with low molecular weight and high melt index, but this will reduce the wear resistance of the lining layer. To obtain a molded lining that is both corrosion-resistant and wear-resistant High molecular weight polyethylene is more difficult

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