Working principle and characteristics of submerged pump

Submerged pump is a single screw pump, which is the main working part of the eccentric spiral screw (called the rotor) and the inner surface of the double helical screw bush (called stator). Its working principle is that when the motor drives the pump shaft to rotate, the screw rotates on its own axis on the one hand, and on the other hand, it rolls along the inner surface of the liner to form a sealed chamber of the pump. Each revolution of the screw, the liquid in the sealed cavity is pushed forward by one pitch. As the screw rotates continuously, the liquid spirally presses from one sealed cavity to the other sealed cavity, and finally the pump body is extruded. Submerged pump is a new type of liquid conveying machinery, with simple structure, safe and reliable work, easy maintenance, liquid continuous and uniform, the pressure stability and so on. A kind of pump which uses the rotation of screw to suck and discharge liquid, which is most suitable for sucking and discharging viscous liquid.The submerged pump uses the rotation of the screw to suck and discharge the liquid. Fig. 1 shows a cross-sectional view of a three-liquid lower pump. In the picture, the middle screw is the active screw which is driven by the prime mover. The screw on both sides is the driven screw, which rotates reversely with the active screw. The main, driven screw thread are double-headed thread. Due to the mutual engagement of the screws and the close cooperation of the screw with the inner wall of the liner, one or more sealed spaces are separated between the suction and discharge of the submerged pump. As the screw is rotated and engaged, these sealed spaces are constantly formed at the suction side of the pump, the liquid in the suction chamber is enclosed therein and continuously displaced in the axial direction of the screw from the suction chamber to the discharge end, to be enclosed in the spaces Discharge of liquid, like a nut in the screw rotation is constantly moving forward, as the case, which is the basic working principle of submerged pump. The sealing surface between the screw and the housing is a curved surface. There are unsealed areas such as ab or de on this surface and a number of triangular notches abc, def with the groove portion of the screw. The notches of these triangles form a passage for the liquid, allowing the drive screw groove A to communicate with the grooves B, C in the driven screw. The grooves B, C, along with their spiral around the back, respectively, and the back of the grooves D, E communicated. Since there are also triangular notches a'b'c 'similar to the front face on the sealing surfaces where the grooves D, E engage with the groove F (which belongs to the other thread), D, F, E will also communicate. In this way, the groove ABCDEA also form a "∞" -shaped sealing space (such as the use of single-head thread, the groove will be along the axial disk Rao screw, the suction port through, can not form a seal). Not hard to imagine, in such a screw, will form a number of independent "∞" -shaped sealed space, each sealed space occupies the axial length exactly equal to the lead of the tired rod t. Therefore, in order to make the suction and discharge of the screw, the length of the screw thread should be longer than one lead. It can be seen from the above working principle, submerged pump has the following advantages: 1) wide pressure and flow range. The pressure is about 3.4-340 kgf / cm2, the flow rate is up to 18,600 cm3 / min; 2) the kind of liquid to be transported and the range of viscosities are wide; 3) because of the low inertial force of the rotating parts in the submerged pump, Speed; 4) good suction performance, self-priming capability; 5) uniform and continuous flow, small vibration, low noise; 6) less sensitive to the incoming gas and dirt than other rotary pumps; Solid structure, easy installation and maintenance. Disadvantages of submerged pumps are the higher machining and assembly requirements of the screw; the performance of the pump is sensitive to changes in the viscosity of the liquid. Submerged pump submerged in the liquid part of the work, the shaft seal no leakage. And covers an area of ​​small, reliable, easy maintenance, corrosion resistance and so on. Submerged pump is widely used in chemical, pharmaceutical, paper, petroleum and other industrial sectors. The vertical motor of the submerged pump is bolted to the motor seat, directly driven by the elastic coupling and the pump, the pump body, the intermediate takeover pipe, the pump rack, the liquid outlet pipe and the pipe flange are integrally connected by a bolt and fixed On the bottom plate, the entire submerged pump is mounted on the container through the bottom plate. Pump axial force and radial force, (including the pump during the operation of the water pressure, impeller and rotor weight, etc.), by the bearing box installed within the one-way thrust ball bearings, single row radial ball bearings; and sliding guide Axis to withstand the normal operation of the pump to ensure safety. Bearings lubricated with butter, guide bearing lubrication with the transport of liquid. Therefore, when the submerged pump work surface level must be higher than the impeller. The length of the extension into the container length L is different, then divided into intermediate bearing structure and intermediate guide bearing structure. Under the pump into the length of the container into the different (usually 1 to 1.5m) made of specifications. Submerged part of submerged pump liquid in the pump, the pump operation of the axial and radial forces were supported by the rolling bearings and plain bearings; therefore quiet and quiet operation. Shaft seal no liquid splash phenomenon. Seal packing at the cooling system, according to the user using the media temperature, with cooling water away heat.