Analysis of sewage pump application

1 Sewage pump is a combination of pump and motor, and at the same time under the pump stealth work products, compared with the general horizontal pump or vertical sewage pump, sewage pump obviously has the following advantages :1. The Structural Parts are compact and have a small footprint. Because of its submersion operation, the sewage pump can be installed directly in the sewage tank. There is no need to build a dedicated pump house to install pumps and machines, which can save a lot of land and infrastructure costs.

2. Easy installation and maintenance. Small sewage pump can be installed freely, large sewage pump is generally equipped with automatic coupling can be automatically installed, installation and maintenance is quite convenient.

3. It can run continuously for a long time. Due to the coaxial pump and motor shaft, the shaft is short, and the rotating parts are light in weight, so the load on the bearing (radial) is relatively small, and the service life is much longer than that of the ordinary pump.

4. There is no cavitation damage and irrigation problems. In particular, the latter point brings great convenience to the operator.

5. Low vibration noise, low motor temperature, no pollution environment.

It is because of the above advantages that sewage pumps have received more and more people's attention, and the scope of use is more and more extensive, from the original simple for transporting fresh water to now can transport a variety of domestic sewage, Chemical Industry industrial wastewater, Building Materials site drainage, liquid feed and so on.

It plays a very important role in municipal engineering, industry, hospital, construction, catering, water conservancy construction and other industries.

But it's all in two parts. The most critical problem of sewage pumps is reliability, because sewage pumps are used in liquid conditions; The medium to be transported is a liquid mixture containing a solid substance; The pump is very close to the motor; The pump is upright, and the weight of the rotating part is in the same direction as the water pressure of the impeller. These problems make the sewage pump in the sealing, motor bearing capacity, bearing layout and selection requirements are higher than the general sewage pump.

In order to improve the service life of sewage pumps, most manufacturers at home and abroad are looking for solutions on the pump protection system, that is, the pump leakage, overload, overtemperature and other faults can automatically alarm and automatically shut down maintenance. However, we think it is necessary to set up a protection system in the sewage pump, which can effectively protect the safe operation of the pump.

But that is not the point. The protection system is only a remedy for pump failure. This is a relatively passive approach. The crux of the problem should be from the beginning to completely solve the problems of sealing and overload in the pump, which is a more active approach. To this end, we apply impeller dynamic water seal technology and pump non-overload design technology to sewage pump, which greatly improves the seal reliability and bearing capacity of the pump, and extends the service life of the pump.

1. Hydrodynamic sealing technology of impeller

The so-called auxiliary impeller fluid seal is to install an open impeller on the opposite side of the coaxial back cover of the pump impeller. When the pump works, the auxiliary impeller rotates with the main shaft of the pump, and the liquid in the auxiliary impeller will also rotate together. The rotating liquid will produce outward centrifugal force, which on the one hand resists the liquid flow to the mechanical seal and reduces the pressure of the mechanical seal. On the other hand, prevent the solid particles in the medium from entering the friction pair of the mechanical seal, reduce the wear of the mechanical seal, and extend the service life of the mechanical seal.

In addition to the sealing effect of the secondary impeller, it can also play a role in reducing the axial force. In the submersible pump, the axial force is mainly composed of the pressure force generated by the liquid pressure on the impeller and the gravity of the entire rotating part. The direction of action of the two forces is the same, and the resultant force is formed by the sum of the two forces. It can be seen that under the same performance parameters, the axial force of the submersible pump is larger than that of the horizontal pump, and the balance is more difficult than that of the vertical pump. Therefore, in the submersible sewage pump, the reason why the bearing is easy to damage also has a great relationship with the axial force.

If the auxiliary impeller is installed, the direction of the liquid pressure applied to the impeller is opposite to the combined force of the above two forces, which can offset a part of the axial force and extend the bearing life.