Working principle of submersible pump

The submersible pump is a water treatment tool with a very wide range of uses. Unlike ordinary pumps, the submersible pump is a direct connection between the motor and the water pump to submerge and work in the water. Submersible pumps can be divided into well submersible pumps, working surface submersible pumps, Submersible sewage pumps, sand discharge submersible pumps, vertical mine pumps, etc. This article combines the maintenance experience of our school for many years to discuss the common failure phenomena and analysis and treatment of deep well submersible pumps in use.

1.Working principle and performance characteristics of submersible pumps

The submersible pump is a general-purpose water-lifting machine that is directly connected to the motor and the water pump to submerge into the water. Its working principle is that the motor drives the impeller to rotate at a high speed through the pump shaft, and works on the liquid under the action of centrifugal force to convert the mechanical energy into liquid energy. The liquid (water) flies away from the impeller and shoots out. The speed of the sprayed liquid in the diffusion chamber of the pump casing gradually slows down and the pressure gradually increases, and then flows out from the discharge pipe of the pump outlet. The design starting point of the submersible pump is "no entanglement, no blockage", and some models are also equipped with a tearing mechanism or cutting device, which can tear long fibers and ribbons in the water and discharge them. The inherent weakness of submersible pumps is that the pumped medium is mostly soft, and the sand content in the water is limited to less than 3%. When the sand content is large, the seal is easily damaged. Once the motor enters water, the insulation of the bearing winding is damaged, causing the motor to burn.

2. Installation and use of deep well submersible pumps

Submersible pumps generally have certain requirements for the upper and lower deviation ranges of power supply voltage and frequency. High-power submersible pumps must be started or soft-started with reduced voltage to reduce the impact on the power grid or other electrical equipment and the submersible pump itself. The installation and use of submersible pumps should be correctly selected according to the use environment and relevant matters should be paid attention to.

2.1 Selection and use environment of submersible pumps

The selection of submersible pumps should be correctly selected according to the characteristics of the working conditions, and the flow, head, installation method and so on are mainly considered when selecting the type. Only selected

When the head is close to the actual required head, the water pump can run with high efficiency and energy saving. Improper selection will have a great impact on the operation of the water pump.

Generally, the use environment of deep well submersible pumps should meet the following requirements:

(1) A three-phase AC power supply with a power frequency of 50 Hz and a rated voltage of ±5%;

(2) The solid content (by mass) is not more than 0.01%;

(3) The pump inlet must be below the water level of 1m, but the diving depth must not exceed 70m below the static water level, and the bottom of the pump must be at least 1m deep from the bottom of the well;

(4) The well is required to be vertical, with smooth walls, and the well pipes must not be staggered.

2.2 Installation of deep well submersible pump

The installation of deep well submersible pumps must first check whether the power supply line, grid voltage, frequency, and control switch meet the conditions of use; secondly, the pump must take good grounding measures; check whether the electric control cabinet is installed correctly and well grounded; check the lifting facilities to be safe and reliable. The installation of the water pump is carried out in the following order:

(1) Remove the water filter screen located in the middle of the water pump, unscrew the water filling screw plug and the water drain screw plug, fill the machine with clean neutral water, and then tighten the screw plug. Check whether there is any leakage at each connection part of the motor, and seal it if there is any leakage.

(2) Use a 500 volt megohmmeter to measure the insulation resistance of the motor to be no less than 150 megohms, and use a screwdriver to pry the impeller should rotate freely without jamming phenomenon.

(3) First connect the short water pipe to the check valve body, install a pair of splints under the upper flange of the short water pipe, and then gently lift it and put it in the well so that the splint is seated on the well cover.

(4) Clamp the long water pipe with another pair of splints and hoist to connect with the short water pipe, then remove the first pair of splints to hoist another long water pipe. Pipes, repeat the installation according to this, then cover the manhole cover and fix the splint on the manhole cover, and finally install the curved water pipe, valve, outlet pipe, deep well submersible pump.

(5) During the installation process, the two flanges of the pipeline should be filled with pipeline rubber gaskets, the bolts should be tightened symmetrically, and the cables should be tied to the water delivery system. In the groove on the pipe flange; do not use the cable as a sling, let alone scratch the cable.