How to select a submersible pump?

The selection of submersible pumps should be based on the process flow, water supply and drainage requirements, and should be considered from five aspects: liquid delivery volume, device head, liquid properties, pipeline layout, and operating conditions. Let’s take a look at the specific submersible pump selection method and the precautions for using submersible pumps.

5 major submersible pump selection methods

  1. Flow rate is one of the important performance data for selecting submersible pumps, which is directly related to the production capacity and delivery capacity of the entire device. When selecting a pump, the large flow rate is used as the basis, taking into account the normal flow rate. When there is no large flow rate, 1.1 times the normal flow rate can usually be taken as the large flow rate.
  2. The head required by the device system is another important performance data for selecting a submersible pump. Generally, the head after enlarging the margin by 5%-10% is used for selection.
  3. The pipeline layout conditions of the submersible pump device system refer to the liquid delivery height, liquid delivery distance, and liquid delivery direction, so as to calculate the system head and check the cavitation margin.
  4. Liquid properties, including the name of the liquid medium, physical properties, chemical properties and other properties. Physical properties include temperature c, density d, viscosity u, solid particle diameter and gas content in the medium, etc. This involves the head of the system, calculation of effective cavitation margin and the type of suitable pump: chemical properties, mainly refer to the chemical corrosiveness and toxicity of the liquid medium, which is an important basis for selecting submersible pump materials and which type of shaft seal to choose.
  5. There are many operating conditions for submersible pumps, such as the operating T of the liquid, saturated steam force P, suction side pressure PS (absolute), discharge side container pressure PZ, altitude, ambient temperature, whether the operation is intermittent or continuous, and whether the position of the pump is fixed or movable.

Precautions for using submersible pumps

  1. Pay attention to the pump bearing temperature, which should not exceed the outside temperature by 35 degrees but should not be greater than 75 degrees.
  2. The oil cup should be filled with calcium-based butter to ensure normal lubrication of the bearing.
  3. The butter in the motor support oil cup should be replaced within the first month of operation or after 100 hours of operation, and replaced every 2000 hours of operation thereafter.
  4. Check the elastic coupling regularly and pay attention to the temperature rise of the motor bearing.
  5. If you find any noise or unusual sound during the running process, you should stop and check immediately.
  6. The pump should be checked periodically every 2000 hours of operation. The wear of the gap between the impeller and the pump body (or pump cover) should not be too large. The maximum value of the gap should not exceed 1.5 mm. If it exceeds, the impeller or front cover can be replaced.
  7. When the pump works for 6 hours, the mechanical seal should be checked and repaired or replaced according to the degree of wear, otherwise it will cause damage to the pump shaft and bearings.

The above are the five methods for selecting submersible pumps and the seven precautions during the use of submersible pumps. Traditional submersible pumps are suitable for long-term transportation of various corrosive media such as strong acids, alkalis, salts, strong oxidants, etc. of any concentration. The new submersible pump is suitable for conveying lightweight, flammable and explosive materials. It is maintenance-free, explosion-proof and has low energy consumption. The casing, main pipe, outlet pipe and flow-through parts of the traditional submersible pump are all made of plastic alloy (PTFE, FEP) by molding and sintering. The main pump part is placed entirely in the liquid. It has strong corrosion resistance, high mechanical strength, is non-oxidative and has no toxic decomposition characteristics.