The project 19RPT02 “Improvement of the realisation of the mass scale” (EMPIR Call 2019 – Energy, Environment, Normative and Research Potential) has just started.<br />Its aim is to improve the quality of one of the most important tasks in mass metrology, the realisation of the mass scale. After the new definition of the kilogram this technique is getting more important.
Designs are presented for casting molds for making hydrocyclone components from plastics in seven standard sizes. The equipment allows to perform a considerable economy in constructional materials and reduce the effort in making hydrocyclones and improves the quality of the surface in the flow sections.Hydrocyclones have recently been used extensively in industry to separate inhomogeneous liquid systems [1-3]. The general industrial use is due to the compactness, convenient assembly in existing plant, high specific throughput, and reliability. On the other hand, those made by Russian industry in the main are made of metal, with low factors for the use of the material, and also difficulties in manufacture, which substantially restrict the scope for series production and the organization of centralized supplies to the chemical and related industries.To resolve the problem of routine hydrocyclone production, the Dzerzhinsk Polytechnical Institute has collaborated with the Moscow State University of Engineering Ecology (MGUIE) in developing a standard series of highly efficient and technologically sound plastic hydrocyclones [4]. The series includes seven standard sizes: TVP-25, TVP-32, TVP-40, TVP-50, TVP-63, TVP-80, and TVP-100 (the numbers correspond to the internal diameters of the body in mm). Technical characteristics are given in [4]. The hydrocyclones are made by pressure casting from strong and corrosion-resistant thermoplastics (polyamide, polystyrene, polycarbonate, and so on).The body 1 of a plastic hydrocyclone is made in a single pass with inlet and outlet tubes, and it has a cone 2 and a sand packing 4, which is impelled into the cone by means of a metal pressure nut 3 (Fig. 1).To organize routine production from plastics from the body, cone, and sand filling, all these standard sizes were accommodated by means of casting molds.Casting mold for making bodies (Fig. 2a): this consists of the mobile half-mold 10 and immobile part 12, together with the plunger 7, sleeves 6 and 11, driving sleeve 16, and expulsion space 4. The mold also includes the threaded inserts 10 and 13, the plates 3, 5, and 8, the flanges 2 and 14, the pin 19, the sleeve 18, the column 17, and the screws 1 and 15. To provide rapid solidification in the half-molds, there are channels 9 for supplying cooling water. A casting mold has one plane of section. To avoid considerable complication in the design, the casting mold works in semiautomatic mode with manual setting of the sleeve 11.Casting mold for making cones of all standard sizes (Fig. 2b): this consists of the immobile part 6 and mobile housing 5, to which are attached the sections of the molds 8, 9, and 10, the immobile flange 7 and the mobile flange 2,
At present prevention of loss of valuable chemical and other types of products with waste waters as well as of environmental pollution by them is an extremely urgent task. In the cases where such products occur in waste waters as finely divided suspended matters, this task can be successfully accomplished by employing apparatuses having hydrocyclone batteries [1][2][3], which make it possible not only to very efficiently clean waste waters from suspended matters, but also to continuously return the recovered valuable products to the production cycle and, if necessary, to sell them as commercial products.At the same time, it must be noted that the designs of the battery hydrocyclone apparatuses produced in Russia so far using metallic hydrocyclones [1, 2] are not adaptable to streamlined production, have a low factor of utilization of the structural material, and their fabrication is highly cumbersome, which greatly impedes their serial production. Exceptions are modular multieyclones assembled from serially produced plastic microcyclones 20 and 30 mm in diameter and used for complementing stations of hydrocyclones employed for washing starch suspensions [4, 5]. However, the narrow range of diameters of the hydrocyelones in these apparatuses hinders their wide application for cleaning waste waters containing suspended matters of the product having a wide size range and having large volumes. The Nizlmii Novgorod State Technical University has developed and been serially producing battery hydrocyelone apparatuses based on plastic hydrocyclones [6] having diameters of 25, 40, 50, 60, 80, and 100 mm (individually linked plastic hydrocyclones and modular). Use of plastic hydrocyclones having a fairly wide range of diameters in these designs makes it possible to select hydrocyclones of a specific diameter to ensure the required efficiency of separation when the waste water contains suspended products differing in size range; the efficiency is ensured by the desired number of hydrocyclones when they are installed in the battery apparatus. Application of plastic hydrocyclones in these apparatuses allowed dramatic reduction of the material content and labor in the manufacture of battery hydrocyelone apparatuses, several-fold reduction of their cost, and their serial production.Battery hydroeyclone apparatuses having individually linked plastic hydrocyclones are designed in two versions. In one version the plastic modules are arranged around a centrally placed collector (Fig. la). This version of apparatuses consists of a collector, a group of hydrocyclones radially arranged around the collector, and a bin. The apparatus functions as follows. The waste water containing suspended particles of the product is fed under pressure through the inlet pipe into the feeding chamber of the collector and then through the pipe 5 into the plastic hydrocyelones where it acquires, due to tangential entry, a vigorous swirling motion. The centrifugal force generated in this process causes separation, the suspended particles move toward the ...
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