Characteristics Of Centrifugal Submersible Sewage Pump

Nov 26, 2024

Centrifugal submersible sewage pump is a type of pump product that is connected to a motor and operates underwater simultaneously. Adopting a large flow channel anti clogging hydraulic component design, it greatly improves the ability of pollutants to pass through, and can effectively pass through 5 times the fiber material of the pump diameter and solid particles with a diameter of about 50% of the pump diameter.
In order to improve the service life of submersible sewage pumps, most manufacturers are now trying to find ways in the pump protection system, which can automatically alarm and shut down for maintenance in case of pump leakage, overload, overheating and other faults.
It is necessary to install a protection system in the submersible sewage pump, which can effectively protect the safe operation of the electric pump. But this is not the key issue, the protection system is just a remedial measure after a pump failure, which is a relatively passive approach.
The key to the problem of sewage pumps should be to start from the root and thoroughly solve the problems of pump sealing, overload, etc. This is a more proactive approach.
In a typical centrifugal sewage pump, the power always increases with the increase of flow rate, that is to say, the power curve is a curve that rises with the increase of flow rate, which brings a problem to the use of the pump:
When the sewage pump operates at the design operating point, generally speaking, if the power of the pump is less than the rated power of the motor, the use of this pump is safe; But when the pump head decreases, the flow rate will increase (as can be seen from the pump's performance curve), and the power will also increase accordingly. When the flow rate exceeds the design operating point and reaches a certain value, the input power of the pump may exceed the rated power of the motor, causing the motor to overload and burn out.
When the motor is overloaded, either the protection system will activate to stop the pump from rotating; Either the protection system fails and the motor burns out. The situation where the pump head is lower than the design operating point head is often encountered in practice. One situation is that when selecting the pump, the pump head is too high, but in actual use, the pump head is reduced; Another situation is that it is difficult to determine the operating point of the pump during use, in other words, the flow rate of the pump needs to be adjusted frequently; There is also a situation where the pump needs to be frequently relocated for use. this
There are three possible situations where the pump may be overloaded and affect its reliability.

It can be said that for pumps without full head characteristics (including submersible sewage pumps), their range of use will be greatly limited. The so-called full head characteristic (also known as overload free characteristic) of a sewage pump refers to the very slow rate at which the power curve rises with increasing flow rate. Ideally, when the flow rate reaches a certain value, the power not only does not rise again, but also decreases. In other words, the power curve is a curve with a hump. If this is the case, as long as we choose a power value slightly higher than the hump point of the motor rated power, the power of the sewage pump will not exceed the motor power and cause the pump to overload in the entire range from 0 flow rate to maximum flow rate. For pumps with this performance, both selection and use will be very convenient and reliable. In addition, the motor power does not need to be too high, which can save considerable equipment costs.