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The use of high viscosity gear pump features
Gear pump is ideal for conveying high viscosity liquid equipment, its wide range of applications, China's oil and chemical industries using high viscosity gear pumps are still mostly dependent on imports.At present, although the domestic enterprises have produced a number of suitable for conveying high viscosity Liquid gear pump, but due to imperfect testing methods, there are still some problems in material selection, leakage and noise control.Especially the domestic high viscosity gear pump has a big gap with foreign products in terms of efficiency, reliability and service life Therefore, the majority of high viscosity gear pumps used in petroleum and chemical industries in our country still depend on imports. The development characteristics of high viscosity gear pumps at home and abroad are as follows: Gear structure: Gear of high viscosity gear pump is common with straight teeth, Herringbone teeth, helical teeth, tooth profile are mainly involute and arc type.Generally, small-sized gear pumps often use involute spur gear, high temperature gear pump often use variable gear, conveying high viscosity, high pressure polymer melt Melt pump more involute helical gear. Gear and shaft made of one, its rigidity and reliability is higher than gear and shaft separately manufactured gear pump. Foreign low pressure tooth Pump gear is often used square structure, that is, gear tooth width equal to the diameter of the tip circle.High pressure occasions, the use of high-viscosity gear pump gear tooth width is smaller than the tip diameter, which is to reduce the gear radial compression Area, reduce gear, bearing load Pump body and heating method: In general, the heavier the gear pump casing, its temperature resistance, compressive strength is also higher.Pump material commonly used ductile iron, can also use the casting Aluminum alloy die casting, or the use of extruded aluminum alloy processing.When the medium is corrosive, the higher cost of stainless steel can be used.Many foreign high viscosity gear pump with nickel, chromium high Alloy steel as the pump shell material, the material in the strength, reliability and cost of the overall performance is better.To solve the gear pump trapped oil phenomenon, usually in the pump cover to open a symmetrical relief groove, or to the low pressure side of the direction Asymmetrical unloading groove is opened, the taper unloading groove is adopted on the liquid absorption side, the rectangular unloading groove is on the liquid discharging side, and the depth of the unloading groove is deeper than the gear pump used in the hydraulic industry. Higher medium viscosity, to reduce the flow Resistance, to enhance the liquid pump suction capacity, the media must be heated or heat.Usually heating elements, can make viscous liquid heat evenly.If the temperature fluctuations, the delivery of high viscosity liquid is prone to degradation, the proposed fluid heating Way, especially large displacement gear pump fluid heating is divided into built-in, external structure.The so-called built-in gear pump body or cover the internal design of the heat jacket, the external is through the bolt will be heat Set with the pump body connected to the jacket into the steam, thermal oil, or cooling water, according to the specific circumstances of the media. Built-in suitable for conveying liquid temperature uniformity requirements or require high temperature liquid When the electric cooling method is lack of safety or the temperature control is not high, the external structure can be adopted. The internal gear pump and the jacket of the pump head can control the temperature of the conveying fluid, Is in high temperature or low temperature environment, can be equipped with an external jacket.