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How does submersible pump works?

What is a submersible pump?

The use of submersible pumps is mainly used as one of the important equipment for deep well water lifting, industrial sewage, and wastewater treatment. The motor of the submersible pump is sealed in a pump casing, so the water will not come into contact with the motor components. It uses the whole unit to submerge in the water to extract the groundwater to the surface, and the groundwater can be used as domestic water. Since we will immerse the submersible pump in water, it will not be affected by the cavitation in the pump. The submersible pumps often seen in the market are mainly used for water intake for wells. The form is mainly a barrel pump. The pump head of the submersible pump is on the top, and the motor is below the water inlet of the pump. The shape of the long barrel pump is It is very suitable for the structure of the wellbore and is more suitable for processing deep well water intake. Besides, submersible pumps can also be used in these activities, such as mine rescue, farmland irrigation, industrial cooling, seawater lifting, construction site drainage, shipload adjustment, and fountain landscapes. The design of submersible pumps can be applied to various types of places, such as areas with narrow environments or complex terrain. It comes with an automatic operation function, so we don't need to check whether it is working normally.

How does the submersible pump work?

The working principle of the submersible pump is to convert its rotational energy into kinetic energy by the pressure sucked in from the pump, and then flow the water to the appropriate surface. Before turning on the submersible pump, we must make sure that the pump and the suction pipe are filled with liquid. After switching on the pump, the liquid in the pump rotates at the high speed of the impeller, and in the case of centrifugal action, the liquid flies away from the impeller and is pumped out. The ejected liquid enters the diffuser, increasing the pressure inside, and then flows out from the outlet of the pump. At this time, due to the liquid being thrown out of the pump, the center of the blade will form a phenomenon of vacuum and low pressure inside. Besides, the liquid in the liquid pool is under the action of atmospheric pressure, and the liquid flows into the pump through the suction pipe and then is pumped out of the pump. This process continues to circulate, and the liquid in the liquid pool is sucked in and then pumped out. While completing the whole process, we must pay attention that the submersible pump must be completely immersed in the liquid pool, and cannot be exposed to the surface, because if it is exposed, it will cause the temperature of the pump to overheat and so on.

Types of Submersible Pump

According to the occasion of use, we can classify the following two types of submersible pumps:

  1. General submersible pump. This type of pump is very convenient to use and is suitable for pumping water in rivers, lakes, shallow wells, and ditches.

  2. Deep well submersible pump. The main feature of this type of pump is its relatively high lift, which is mainly used in pools with relatively deep water levels, such as deep wells.

According to the way the motor is waterproof, it can be divided into the following three types of submersible pumps:

  1. Water-filled submersible pump. This type of submersible pump mainly uses waterproof insulated wires, which are characterized by better materials and higher rust resistance. The water in its motor is clean, and the rotor runs in the water.

  2. Oil-filled submersible electric pump. According to its name, its motor is filled with insulating oil, which can prevent damage to the motor in a humid environment. Besides, this insulating oil has the function of lubrication and cooling. But when its sealing cover is damaged, the insulating oil in its motor will flow out, contaminating the pool. Therefore, it is not suitable for the delivery of drinking water.

  3. Dry submersible pump. Mainly use mechanical sealing methods to prevent outside water from entering the motor to keep the motor dry.

Advantages and Disadvantages

Before we buy a submersible pump, we must first understand its advantages and disadvantages.

First, let's understand its advantages:

  1. Lightweight. The motor of the submersible pump is integrated with the water pump, and there is no need to have a long driveshaft.

  2. Maintenance costs are small. The motors of submersible pumps generally use water for lubrication and cooling, so they do not require high costs for maintenance.

  3. Easy to operate. There is no need to spend too much money and time to control it.

  4. It is very quiet in operation. Because this type of pump works underwater.

Besides, we also need to consider its shortcomings:

  1. There are restrictions on the structure and use of submersible pumps. For example, some submersible pumps are only suitable for use in wells.

  2. Since most submersible pumps are immersed in water, our installation and maintenance process is more difficult than ordinary pumps.

  3. Seals or cables are susceptible to aging and corrosion, and water can easily penetrate the motor, causing leakage and damage.

  4. If the water in the pool is not exhausted, when the water level is too low, the temperature of the pump may be overheated and the pump may malfunction.

Different Between Centrifugal Pump and Submersible Pump

1. Submersible pump

The most obvious difference between submersible pumps and centrifugal pumps is that submersible pumps work in water, while centrifugal pumps work on the ground. The use of submersible pumps is mainly suitable for farmland irrigation, seawater lifting, construction site drainage, and livestock water in high mountain areas. Besides, it can also be used for central air conditioning cooling, heat pump units, cold pump units, and so on. The submersible pump is mainly composed of a control cabinet, a submersible cable, a submersible electric pump, and a submersible motor.

2. Centrifugal pump

The working principle of the centrifugal pump is to use the high-speed rotation of the impeller to throw water to the destination. Centrifugal pump is mainly composed of impeller, pump shaft, pump body, pump cover, bearing, sealing ring, stuffing box, and other components. The main purpose of centrifugal pumps is to be used as drainage in various industrial fields, such as construction, electric power, metallurgy, coal, and other industries, to transport liquids containing solids or particles. To know more about the centrifugal pump, can read through our article here:


MecHero is a one-stop solution company which provides a wide range of mechanical hardware products such as piping accessories, steel products, aluminium products, painting tools, genset, and fabrication service for engineering works.

Photo credit: Pixabay, Indiamart, SLB

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