The most popular use of special plastics for envir

2022-07-27
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The use of special plastics for environmental protection mechanical pumps to prevent cavitation damage

plastic pumps are gradually replacing metal materials in some applications because they are suitable for liquids with various viscosities, have a wide range of applications, can transport all flowing media and even non flowing materials, have strong suction capacity, low working noise, no leakage, no temperature rise and other advantages

cavitation has always been a great hazard to pump materials. Cavitation refers to that when the pressure of liquid is reduced to the vaporization pressure at a certain temperature, the liquid will produce bubbles. When the generated bubble flows to a high pressure, its volume decreases to the point of collapse. The phenomenon that bubbles disappear in the liquid due to pressure rise is called cavitation collapse

during the operation of the pump, if the absolute pressure of the pumped liquid decreases to the vaporization pressure of the liquid at the current temperature in the local area of the flow passage part (usually somewhere later at the inlet of the impeller blade) for some reason, the liquid begins to vaporize there, producing a large amount of steam and forming bubbles. When the liquid containing a large amount of bubbles passes through the high-pressure area in the impeller, The high pressure liquid around the bubble causes the bubble to shrink sharply and even burst. At the same time of bubble condensation and fracture, the liquid particles fill the holes at a very high speed, which produces a very strong water hammer effect at this moment, and strikes the metal surface with a very high impact frequency. The impact stress can reach hundreds to thousands of atmospheres, and the impact frequency can reach tens of thousands of times per second. In serious cases, the wall thickness will be broken down, resulting in the cracking of the workpiece

the cavitation process in the water pump is the process that bubbles are generated and broken in the water pump, causing the flow passage components to be damaged. In addition to damaging the flow passage components, the cavitation of the water pump will also produce noise and vibration, which will degrade the performance of the pump. In serious cases, the liquid in the pump will be interrupted and cannot work normally

the effective measure to reduce cavitation is to prevent foaming. First of all, the surface moving in the liquid should be streamlined to avoid local eddy current, because the pressure injection molding, reaction processing and extrusion technologies in the eddy current area are the three major technologies of Klaus mafi group, which are low and easy to generate bubbles. In addition, the air content in the liquid and the disturbance in the liquid flow should be reduced, which will also limit the formation of bubbles

choosing appropriate materials can improve the cavitation resistance. High rigidity and high toughness materials have good anti cavitation effect. Shanghai rizhisheng New Technology Development Co., Ltd. has successfully developed a glass fiber reinforced polypropylene material specially used for environmental protection mechanical pumps in combination with its own chemical modification advantages. The material has excellent performance, excellent injection appearance and good resistance to acid-base corrosion caused by semicircular additional stress due to the wedging effect of support points, which can better resist the cracking of parts caused by cavitation

it is a long-term research topic to prevent and reduce the harm caused by cavitation erosion. Part design and the selection of material electronic tensile testing machine, also known as electronic tensile machine, all affect the service life of products. Selecting appropriate materials will greatly improve the service life of the pump and minimize the cost pressure caused by material replacement

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