Five aspects of correct selection of sludge screw pump
The screw pump is a positive displacement pump, and the main working parts are composed of a stator and a rotor. The rotor is a screw with a large lead, a large tooth height and a small inner diameter of the thread, while the stator is an elastic bushing with a double-ended helix. The rotor and stator cooperate with each other to form a sealed cavity that does not communicate with each other During internal rotation, the sealed cavity moves from the suction end of the pump to the discharge end in the axial direction, and the medium is continuously transported from the suction end to the discharge end in the cavity.
If the design and selection are not considered carefully, it will bring trouble to the future use, management and maintenance. Therefore, choosing a reasonable and reliable screw pump according to the actual needs of production can not only ensure smooth production, but also reduce repair costs.
1. Selection of the rotational speed of the screw pump
The flow rate of the screw pump has a linear relationship with the rotational speed. Compared with the low-speed screw pump, the high-speed screw pump can increase the flow and head, but the power increases significantly. The high speed accelerates the wear between therotor and the stator, which must make The screw pump fails prematurely, and the length of the stator and rotor of the high-speed screw pump is very short, which is extremely easy to wear, thus shortening the service life of the screw pump. Therefore, the service life of the screw pump is shortened.
The speed is reduced by the deceleration mechanism or the stepless speed regulating mechanism to keep the speed within a reasonable range of less than 300 rpm. Compared with the high-speed screw pump, the service life can be extended several times.
2, the quality of the screw pump
There are many types of screw pumps on the market. Relatively speaking, imported screw pumps are of reasonable design and high-quality materials, but the price is high, the service is not in place, the price of accessories is high, and the order cycle is long, which may affect the normal production. run. Most of the domestically produced products are imitation imported products, and the quality of the products varies. When choosing domestically produced products, when considering their cost-effectiveness, choose products with low rotational speed, long lead, excellent material for transmission components, and long rated life.
3. Ensure that debris does not enter the pump body
The solid debris mixed in the wet sludge will damage the rubber stator of the screw pump, so it is very important to ensure that the debris does not enter the cavity of the pump. Many sewage plants have installed a pulverizer in front of the pump, and some have installed them. The grille device or filter screen can prevent the sundries from entering the screw pump, and the grille should be removed in time to avoid blockage.
4. Avoid material breakage
The screw pump is never allowed to run under the condition of material failure. Once it occurs, the rubber stator of the outlet pressure of the screw pump will be burnt out due to dry friction, resulting in an instant high temperature. Therefore, the pulverizer is in good condition and the grille is unobstructed. One of the conditions, for this reason, some screw pumps are also equipped with a material-cutting shutdown device on the pump body. When the material is cut off, due to the self-priming function of the screw pump, a vacuum will be generated in the cavity, and the vacuum device will stop the screw pump. run.
5. Maintain constant outlet pressure
The screw pump is a positive displacement rotary pump. When the outlet end is blocked, the pressure will gradually increase, so that it exceeds the predetermined pressure value. At this time, the motor load increases sharply. The load of the relevant parts of the transmission machinery will also exceed the design value, and in severe cases, the motor will be burned and the transmission parts will be broken. In order to avoid damage to the screw pump, a bypass overflow valve is generally installed at the outlet of the screw pump to stabilize the outlet pressure and maintain the normal operation of the pump.