Manufacturing method and structure of three-dimensional plastic impeller of centrifugal pump

Abstract

The invention relates to a manufacturing method for molding and producing a three-dimensional plastic impeller of a centrifugal pump by using a mold and a structure of the three-dimensional plastic impeller of the centrifugal pump. A twisted blade mold and an impeller outlet mold are included. The twisted blade mold is used for molding twisted blades of all blades of the impeller. The impeller outlet mold is used for molding the rear end parts of the blades, an annular outer rear cover plate of the impeller and an annular outer front cover plate of the impeller, so that the annular outer rearcover plate, the annular outer front cover plate and the blades are molded into a whole at one time in the same molding step.

Description

technical field [0001] The present invention relates to a manufacturing method of a pump impeller, especially a manufacturing method of a pump impeller made of engineering plastics, which is suitable for the production of plastic impellers with high-efficiency three-dimensional flow channels, and can be injection molding or transfer molding, etc. method, and can solve the problem of easy production but low efficiency of traditional two-dimensional impellers. Background technique [0002] The issues of saving energy and reducing carbon dioxide emissions have been valued by various countries. Improving the efficiency of power machinery and equipment has also become the direction of efforts of various practitioners. According to the statistics of the International Energy Agency (IEA), the power consumption of pumps accounts for about 50% of the power consumption of motors. 19%, and since 2015, the European Union has stipulated that the minimum energy efficiency index (MinimumEf...

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Problems solved by technology

[0018] 1. Use a five-axis processing machine to carve a solid piece of plastic into an impeller with a three-dimensional blade surface. However, this method will cause a lot of material waste and high processing costs, such as narrow flow channel width or highly distorted blade shape. are not suitable for such processing methods;

[0019] 2. Use a five-axis processing machine to carve a solid piece of plastic into an impeller with a 2.5-dimensional blade surface. Although the former method can be conveniently used for flank milling, this processing method still has It causes a lot of waste of materials and high processing costs, and the linear elements of the blade surface reduce the degree of distortion of the blade and also reduce the efficiency of the pump, so it still cannot fully meet the flow field requirements;

[0020] 3. The three parts of the impeller, such as the front cover, multiple blades and the rear cover, are molded and produced, and then assembled by means of ultrasonic or thermal welding. However, the blades and front cover of this processing method It is not integrally formed with the rear cover in a single process, and there are seams or structural discontinuities between the components, resulting in weak structural strength, which is easy to be used in applications with high operating temperature (such as about 200°C) or high load damage;

[0021] 4. Divide the entire set of twisted blades of the impeller into two groups. Some blades are produced in one piece on the front cover and the rear cover respectively. Most of the blades are divided into half in even numbers, and then combined into impellers by ultrasonic or welding. Although the fan-shaped channel width (sector width) space between the blades is increased, the twisted blades at the leading edge of the blades cannot be demoulded directly in the axial or radial direction, and a slider demoulding mechanism is still required, and such a design has advantages Half of the blades are only connected by ultrasonic or hot-melt methods, and there is still the problem of weak structural strength and easy damage to high-temperature (such as 200°C) and high-load applications;

[0022] 5. Use two-dimensional blade geometry instead of three-dimensional twisted blades to replace the changing flow field streamlines with simple arc lines, so that the mold slider can be taken out smoothly, but the pump performance of the two-dimensional blades Low, on the contrary, it will reduce the efficiency and fail to meet the pump energy efficiency requirements of the European Union;

[0023] 6. Another practitioner uses the lost foam method to form the impeller, but the lost foam cannot be reused, and additional chemicals or heating must be used to decompose the lost foam core, which leads to complicated manufacturing processes and increased costs, which does not meet the needs of economic production;

[0055] Reference 16 has a mold structure for closed plastic impellers, which is used to produce integrally formed impellers. The upper and lower parts are used to combine the slider core and mold mechanism extracted radially, and the impeller is produced by injection molding. However, reference 16 The axially separated mold is not used, so it is impossible to manufacture three-dimensional twisted blades, and the diagram in reference 16 also shows that the impeller has a two-dimensional structure, so it is difficult to meet the high efficiency requirements

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