Flour or starch is boiled with water to form a paste. Paste has a certain viscosity and is mostly used for bonding paper, cloth or objects. Most of the modern production is a chemical paste made of cellulose and glue. Wheat starch is used as the raw material, and the concentration of starch: water = 1:6 when making the paste, the properties of the prepared paste are relatively stable, and the cooking temperature should not exceed 80°C.
Therefore, according to the characteristics of the paste, it is recommended to use a high-viscosity pump or a single-screw pump. Below we introduce the high-viscosity pump and the single-screw pump:
1. High viscosity pump
NYP inner ring high viscosity pump is a positive displacement inner rotor pump. This type of pump has strong self-priming performance and is suitable for transporting viscous liquids without solid particles and fibres, even semi-solid liquids, with a high transport viscosity of 3*105 centipoise. It has the advantages of small size, lightweight, small pulsation, low noise, stable operation and long life.
2. Single screw pump
The single screw pump belongs to the rotor-type volumetric pump, which relies on the meshing of the screw and the bush to produce volume changes in the suction chamber and the discharge chamber to transport the liquid. It is an internal meshing hermetic screw pump, the main working parts are composed of a bush (stator) with a double-ended helical cavity and a single-ended helical screw (rotor) meshing with it in the stator cavity.
When the input shaft drives the rotor around the centre of the stator to make a planetary revolution through the universal joint, the stator-rotor pair is continuously engaged to form a sealed cavity, and the volume of these sealed cavities moves at a constant speed, and the conveying medium is transported from the suction end to the discharge end through the stator-rotor pair, and the medium sucked into the sealed cavity flows through the stator without being stirred and damaged.
Single screw pump classification: overall stainless steel single screw pump, shaft stainless steel single screw pump.
The specifications of the selected pump are determined according to the nature, flow and pressure of the liquid to be transported, while the speed of the pump is selected by the viscosity and corrosiveness of the transported liquid as the main parameters to ensure the reliable operation of the pump.
The design speed of the pump is the maximum allowable speed when conveying clean water or non-corrosive liquids similar to clean water. In actual use, due to the different properties of the medium and the life requirements, the selection should generally be lower than the design speed.
For high-viscosity and particle-containing media, generally use 1/2-1/3 of the design speed or lower. Low speed is beneficial to the wear of the pump, but after use, due to the wear of the stator, the flow rate will decrease. At this time, it is also a common policy to increase the speed appropriately to compensate for the decrease in flow rate. The temperature of the conveying medium should be -10 ℃ ~ 80 ℃, and it can be as high as 120 ℃ in special cases.