How to Select Suitable Submersible Axial Flow PUMPS Parameters

I.Submersible Axial Flow PUMPS Model Selection Standards

     The submersible axial flow PUMPS is a widely used general-purpose industrial equipment. It is extensively applied in petroleum, chemical industry, electric power, metallurgy, mining, shipbuilding, light industry, agriculture, civilian use, and national defense sectors, playing an important role in the national economy. According to statistics, the annual production of PUMPSs in China reaches 1.256 million units. The electricity consumption of submersible axial flow PUMPSs accounts for more than 21% of the country’s total electricity consumption. Therefore, reducing PUMPS energy consumption is of great significance for energy saving and resource conservation.

     In recent years, the industry has developed many high-efficiency and energy-saving products, such as QZB PUMPSs, QHB PUMPSs, ZLB PUMPSs, ZXB PUMPSs, GLB PUMPSs and other specifications of Submersible Axial Flow PUMPS Models , which have played a positive role in reducing PUMPS energy consumption. However, at present, due to unreasonable model selection in various sectors of the economy, many submersible axial flow PUMPSs operate under improper conditions with low efficiency, resulting in significant energy waste. Some PUMPSs cannot even be used due to improper model selection, or the maintenance cost increases and economic benefits decrease. Therefore, reasonable PUMPS selection is equally important for energy saving.

     Reasonable PUMPS selection means comprehensively considering the investment and operating costs of the PUMPS unit and PUMPSing station, so that it meets the requirements of economy, safety, and applicability. Specifically, the following aspects should be considered:

     The selected PUMPS must meet the requirements of flow rate and head, that is, the operating point of the PUMPS (the intersection of the system characteristic curve and the PUMPS performance curve) should always operate in the high-efficiency zone to save energy and avoid component damage.

     The selected submersible axial flow PUMPS should have good performance and high efficiency, as weir as excellent anti-cavitation performance. This can reduce the excavation depth of the PUMPS station foundation while preventing cavitation, ensuring stable operation and long service life. Building a PUMPSing station based on the selected PUMPS model helps reduce project investment and operating costs.

II.Submersible Axial Flow PUMPS Selection Process

     （1）List basic data:

      1. Material characteristics: material name, density, viscosity, corrosion properties, toxicity, etc.

      2. Particle size and content of solid particles contained in the medium.

      3. Medium temperature: (℃)

      4. Required flow rate. In general industrial applications, leakage in the pipeline system can be ignored, but process variations affecting flow must be considered. For agricultural PUMPSs using irrigation channels, water leakage and annual rainfall must also be considered.

      5. Pressure: suction tank pressure, discharge tank pressure, and pipeline system pressure loss (head loss).

      6. Pipeline system data (pipe diameter, length, pipe fittings type and quantity, geometric elevation from suction tank to discharge tank, etc.).

     If necessary, system characteristic curves should be drawn. When designing pipeline layout, the following should be considered:

      A. Select a reasonable pipe diameter. A larger diameter results in lower flow velocity and friction loss but higher cost; a smaller diameter increases friction loss, raises the required PUMPS head and power consumption. A technical and economic comparison should be made.

      B. The discharge pipe and its fittings must withstand the maximum allowable pressure.

      C. The pipeline layout should be as straight as possible, minimizing fittings and shortening pipe length. When bends are necessary, the bend radius should be 3–5 times the pipe diameter, and the angle should preferably exceed 90°.

      D. The discharge side of the Submersible Axial Flow PUMPS must be equipped with a gate valve (or globe valve, etc.) and a check valve. The gate valve is used to adjust the operating point of the PUMPS, while the check valve prevents reverse flow and PUMPS reversal and protects the PUMPS from water hammer impact (reverse flow generates high reverse pressure that may damage the PUMPS).

III. Determining Flow Rate and PUMPS Head

      a. If minimum, normal, and maximum flow rates are provided in the process, the maximum flow rate should be used for selection.

      b. If only the normal flow rate is given, a safety margin should be added. For PUMPSs with ns > 100 (large flow, low head), the flow margin is 5%; for PUMPSs with ns < 50 (small flow, high head), the margin is 10%; for PUMPSs with 50 ≤ ns ≤ 100, the margin is 5%; for PUMPSs with poor quality or extreme operating conditions, the margin should be 10%.

      c. If only mass flow is given, it should be converted into volumetric flow.