Rational use of screw pump in conveying sewage media

Because of its variable transport, self-priming ability, reversible, can carry liquid containing solid particles, etc., in sewage treatment plants, it is widely used in water transport, wet sludge and flocculant liquid. Screw pump should be used in accordance with economic, fair and reliable criteria. If the design and selection is not well thought out, it will bring trouble to the future use, management and maintenance, so the use of a screw pump according to the needs of production practice, fair and reliable can not only guarantee the smooth production, but also reduce the repair cost. Some of our understandings in the use of screw pumps are introduced as follows:

First, screw pump speed

The flow rate of the screw pump is linearly related to the speed of the low speed screw pump, although the high speed screw pump can add flow and head, but the power is clearly increased, the high speed speed speeds up the wear between the rotor and the stator, which certainly makes the screw pump prematurely fail, and the fixed rotor length of the high speed screw pump is very short, easy to wear, so the service life of the screw pump is shortened.

Through the deceleration mechanism or stepless speed regulation mechanism to reduce the speed, so that the speed insists on a more reasonable limit below 300 revolutions per minute, compared with the high-speed screw pump, the service life can be extended several times.

Second, the quality of the screw pump

At present, there are more varieties of screw pumps on the market, relatively speaking, the inlet screw pump design is fair, the material is excellent, but the price is high, the service is not in place, the accessory price is high, the order cycle is long, which can affect the normal operation of production. Most of the imported products produced in China are imitated, and the quality of the products is uneven. When using the products produced in China, we use low speed, long lead, excellent material and long extra life of the products when thinking about their cost performance.

Third, ensure that debris does not enter the pump body

The solid debris mixed in the wet sludge will damage the rubber material stator of the screw pump, so it is very important to ensure that the debris does not enter the pump chamber, many sewage plants install a crusher before the pump, and some device grid installation or filter to prevent debris from entering the screw pump, about the grid should be cleaned in real time so as not to form an infarction.

Fourth, prevent material breaking

Screw pump is never allowed to operate in the event of material failure, once the fire occurs, the rubber stator is burned out due to dry friction, and the high temperature occurs instantly, so the grinder is missing, grid dredging is one of the requirements for normal operation of the screw pump, for this reason, some screw pumps are also installed on the pump body to stop the installation of material failure, when the fire occurs, because the screw pump has the characteristics of self-priming function, There will be a vacuum in the cavity, and the vacuum installation will stop the operation of the screw pump.

Fifth,Adhere to constant outlet pressure

Screw pump is a positive displacement reverse pump, when the outlet is blocked in the future, the pressure will gradually increase, so that it exceeds the predetermined pressure value. The motor load increases sharply at this time. The load of the related parts of the transmission machinery will also exceed the design value, and the ignition motor will be destroyed and the transmission parts will be broken in serious cases. In order to prevent damage to the screw pump, a bypass relief valve is usually installed at the outlet of the screw pump to change the outlet pressure and adhere to the normal operation of the pump.

Key words: screw pump, conveying sewage