Screw pump divided by the number of screws. Single Screw Pump - A single screw engages a rotating pump in the female thread groove of the pump body. Twin Screw Pump - A pump that pumps liquid between two screws. Multi-Screw Pump - A pump that pumps liquids by engaging multiple screws. Single screw pump is a single screw pump, its main working parts are eccentric screw spiral (referred to as 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. Screw pump is a new type of liquid conveying machinery, with the advantages of simple structure, safe and reliable operation, convenient use and maintenance, continuous and uniform liquid discharge, and stable pressure. A pump that uses the rotation of a screw to pump liquid, which is best suited for absorbing viscous liquids. The basic working principle of screw pump 1. Screw pump is the use of screw rotation to suction and discharge liquid. The figure shows a cross-sectional view of a three-screw 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. Active screw driven screw thread are double-headed thread. Due to the mutual engagement of the screws and the tight fit of the screw with the inner wall of the liner, one or more sealed spaces are separated between the suction and discharge of the pump. As the screw is rotated and engaged, these sealed spaces are constantly formed at the suction side of the pump, sealing the liquid in the suction chamber therein and continuously displacing in the axial direction of the screw from the suction chamber to the discharge end to be closed in the respective spaces Continued discharge of liquid, like a nut in the screw rotation is constantly moving forward, as the case, which is the basic working principle of the screw pump. 2. The working principle of the screw pump is: When the screw pump is working, the liquid is inhaled and then enters the sealed space surrounded by the screw thread and the pump shell. When the driving screw rotates, the screw pump sealing volume is increased under the extrusion of the screw tooth to improve the screw pump Pressure, and axial movement. Since the screw is rotating at a constant speed, the flow of liquid out is also uniform. Screw pump features: screw pump loss, good economic performance. High pressure and uniform, uniform flow, high speed, with the original direct motivation. Screw pump can transport lubricating oil, conveying fuel, conveying a variety of oils and polymers for conveying viscous liquid. Transport high viscosity media: 3. According to the size of the pump can deliver viscosities from centipoise medium. Medium containing particles or fibers: The particle diameter can be 30mm (not exceeding rotor eccentricity). The fiber length can be 350mm (equivalent to the pitch of 0.4 rotor). Its content is generally up to 40% of the media pit, the medium if the solid matter is a fine powder, the maximum content of up to 60% or more can also be transported. Requires delivery pressure is stable, the media do not like to destroy the inherent structure, the selection of single screw pump ideal delivery. Pump often encounter problems 1. Pump violent vibration or noise: Reason: Pump installation is not strong or the pump installed too high; Motor ball bearings damaged; Pump spindle bending or spindle with the motor is not the heart, not parallel and so on. Treatment: install a steady pump or reduce the installation height of the pump; replace the motor ball bearings; correct the bending of the pump shaft or adjust the relative position of the pump and the motor. 2. Drive shaft or motor bearing overheating: Causes: lack of lubricant or bearing rupture. Approach: add oil or replace the bearing. 3. The pump does not water: causes: pump and suction pipe did not fill the diversion; water level lower than the pump filter; suction pipe rupture. 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. Screw pump advantages From the above work can be seen, screw pump has the following advantages: 1) wide pressure and flow range. A pressure of about 3.4-340 kgf / cm 2, a flow rate of up to 18,600 cm 3 / min; 2) a wide range of fluid types and viscosities to be transported; and 3) a high rotational speed ; 4) good suction performance, self-priming capability; 5) uniform flow rate, low vibration, low noise; 6) compared with other rotary pumps, the gas and dirt into the less sensitive; 7) solid structure, installation Easy to maintain. The disadvantage of the screw pump is that the screw machining and assembly requirements are higher; the performance of the pump is sensitive to changes in the viscosity of the liquid. 4 screw pump management 4.1 start screw pump suction stop valve should be fully open in case of starting to prevent overload or suction air. Although the pump has dry suction capacity, but must prevent dry rotation, so as not to scratch the work surface. If the pump needs to be started with very low oil temperature or high viscosity, it should be started with the suction valve and by-pass valve fully open to minimize the load when starting the pump. Until the prime mover reaches the rated speed, Bypass valve gradually closed. When the by-pass valve is opened, the liquid is circulated and circulated in the pump under the condition of throttling, and the more the circulating oil is, the longer the circulating time is, the more severe the heat of the liquid is, and even the pump factor High temperature deformation and damage, we must pay attention. 4.2 operating screw pump must be in accordance with the established direction of operation to produce a certain suction row. Pump work, should pay attention to check the pressure, temperature and mechanical seal work. Shaft seal should allow a trace of leakage, such as leakage does not exceed 20-30 seconds / drop, then that normal. If the pump is noisy at work, it is often caused by too low an oil temperature, too high a viscosity of the fluid, air entering the fluid, loss of coupling, or excessive wear on the pump. 4.3 Parking pump stop, you should close the discharge stop valve, and stop the pump fully stop after inhalation stop valve. 4.4 screw pump working screw length larger, less rigid, easily lead to bending, resulting in abnormal work. Shaft connection must be well centered; the best work is to be carried out after the installation of positioning, so as not to cause deformation of the pipeline implicated; connection pipe should be independently fixed, as far as possible to reduce the implication of the pump. In addition, the spare screw, the best preserved in the use of hanging fixed method to avoid distortion caused by uneven placement of the third century BC, Archimedes invented the spiral rod, the water can be smooth and continuous to a few meters high , The principle is still used by modern screw pump. 1. Single screw pump pressure to determine: single screw pump maximum output pressure is based on the number of bushings that is, the number of bushings to determine: 1: the maximum working pressure of 0.6 MPa; 2: the maximum working pressure of 1.2 MPa ; Level 4: The maximum working pressure is 2.4 MPa; 4. Material combination options: Different media are required to be transported with different material combinations. 5. Performance: General single screw pump performance charts or characteristic curves are 20C water as a medium (viscosity 1cst) when the data for the delivery of different viscosity flow and shaft power are different. 6. Shaft seal: According to the needs and transmission medium, mechanical seal and packing can be sealed two, and the two structures are interchangeable. 7. Pump drive mode: & nb
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