Dry screw vacuum pumps are widely used in the transportation of water, wet sludge in sewage treatment plants due to their characteristics of variable delivery, strong self-priming ability, reversibility, and ability to transport liquids containing solid particles Fluid aspect.
How to choose dry screw vacuum pump correctly in sewage treatment? The selection of screw pumps should follow the principles of economy, rationality and reliability. If the design and selection is not considered carefully, it will cause troubles in future use, management and maintenance, so choosing a reasonable and reliable screw pump according to the actual needs of the production can not only ensure smooth production, but also reduce repair costs.
So, how to choose dry screw vacuum pump correctly in sewage treatment? You can choose from the following five aspects.
First, the selection of the speed of the screw vacuum pump
The screw pump’s flow rate and linear speed have a linear relationship. Compared with low speed screw pumps, high speed screw pumps can increase the flow and head, but the power is significantly increased. The high speed accelerates the wear between the rotor and the stator, which must make the The screw pump fails prematurely, and the stator and rotor length of the high-speed screw pump is very short, which is easy to wear, thus shortening the service life of the screw pump.
The speed is reduced by a speed reduction mechanism or a stepless speed regulation mechanism to keep the speed within a reasonable range of less than three hundred revolutions per minute. Compared with high-speed screw pumps, the service life can be extended several times.
Second, the quality of screw vacuum pump
There are many types of screw pumps on the market. When considering its cost performance, products with low speed, long lead, excellent transmission component materials and long rated life should be selected. For example, Shanghai EVP brand dry screw pumps, it has a certain reputation at home and abroad, and its fine workmanship is a good choice.
Third, ensure that debris does not enter the pump body
The solid debris mixed in the wet sludge will cause damage to the rubber pump stator of the screw pump, so it is important to ensure that debris does not enter the cavity of the pump. Many sewage plants have installed a grinder in front of the pump, and some have installed The grille device or filter screen prevents debris from entering the screw pump. The grille should be cleaned in time to avoid blocking.
Fourth, avoid material breaks
Screw pumps are not allowed to run under a cut-off situation. Once this occurs, the rubber pressure of the screw pump’s outlet pressure stator will burn out due to dry friction and instantaneous high temperature. Therefore, the crusher is intact and the grid is unblocked is a necessary condition for the normal operation of the screw pump. One, for this reason, some screw pumps are also equipped with a material stopping and stopping device on the pump body. When a material break occurs, due to the self-priming feature of the screw pump, a vacuum will be generated in the cavity. The vacuum device will stop the screw pump from running. .
Five, maintain a 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 a 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. In severe cases, the motor will burn out and the transmission parts will break. In order to avoid damage to the screw pump, a bypass relief valve is usually installed at the screw pump outlet to stabilize the outlet pressure and maintain the normal operation of the pump.
Key words: dry pump, dry screw vacuum pump
Edited by: Emily Fu / Shanghai EVP Vacuum Technology Co., Ltd.