Submersible Well Pump Head: A Comprehensive Guide

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The submersible well pump head, also known as the total dynamic head (TDH), is a crucial factor in determining the performance and efficiency of a submersible pump. It is the sum of the static water level, the vertical rise, and the friction loss in the system, which collectively determine the overall pressure and flow characteristics of the water collection system.

Understanding the Components of Submersible Well Pump Head

Static Water Level

The static water level is the height of the water table from the ground level. This measurement is essential in determining the depth at which the submersible pump needs to be installed to ensure reliable and consistent water supply. The static water level can vary depending on the geographical location, seasonal changes, and other environmental factors.

Vertical Rise

The vertical rise is the distance between the pump and the point of water discharge, such as a storage tank or a distribution system. This measurement is crucial in calculating the total lift required for the pump to overcome the vertical distance and deliver the water to the desired location.

Friction Loss

The friction loss is the resistance to the flow of water caused by the roughness of the pipe surface, fittings, and valves. This loss can significantly impact the overall performance of the submersible pump, as it can reduce the available pressure and flow rate. Factors that contribute to friction loss include:

  1. Pipe Length: The longer the pipe, the greater the friction loss.
  2. Pipe Diameter: Smaller pipe diameters result in higher friction loss.
  3. Pipe Material: Rougher pipe materials, such as galvanized steel, have higher friction loss compared to smoother materials like PVC or HDPE.
  4. Fittings: Elbows, tees, couplings, adapters, and other fittings can create additional friction loss, which must be accounted for in the TDH calculation.
  5. Valves: Gate valves, check valves, and other valves in the system can also contribute to friction loss.

Calculating Submersible Well Pump Head

submersible well pump head

The formula for calculating the total dynamic head (TDH) of a submersible pump is:

TDH = Pumping Level + Vertical Rise + Friction Loss

Where:

  • Pumping Level: The depth from the ground surface to the water level in the well.
  • Vertical Rise: The distance from the pump discharge to the point of water delivery.
  • Friction Loss: The pressure drop due to the resistance to water flow in the piping system.

The friction loss can be calculated using the following formula:

Friction Loss = [Pipe Length + (Fittings Equivalent × Number of Fittings)] × Friction Loss per 100 feet of Pipe

Where:

  • Pipe Length: The total length of the pipe from the pump to the point of water delivery.
  • Fittings Equivalent: The equivalent length of pipe for each type of fitting, such as elbows, tees, couplings, and valves.
  • Number of Fittings: The total number of each type of fitting in the system.
  • Friction Loss per 100 feet of Pipe: The pressure drop per 100 feet of pipe, which can be found in manufacturer’s data or calculated using the Hazen-Williams or Darcy-Weisbach equations.

Factors Affecting Submersible Well Pump Head

Several factors can influence the submersible well pump head, including:

  1. Flow Rate: As the flow rate increases, the friction loss also increases, leading to a higher TDH.
  2. Pipe Diameter: Larger pipe diameters result in lower friction loss and, consequently, a lower TDH.
  3. Pipe Material: Smoother pipe materials, such as PVC or HDPE, have lower friction loss compared to rougher materials like galvanized steel.
  4. Fittings and Valves: The number and type of fittings and valves in the system can significantly impact the friction loss and, therefore, the TDH.
  5. Water Quality: Factors like water hardness, sediment, and dissolved solids can affect the roughness of the pipe surface, leading to increased friction loss over time.
  6. Pump Efficiency: The efficiency of the submersible pump itself can also impact the TDH, as a more efficient pump can deliver the same flow rate with lower power consumption and pressure requirements.

Optimizing Submersible Well Pump Head

To optimize the submersible well pump head and ensure the efficient operation of the water collection system, consider the following strategies:

  1. Accurate Measurements: Carefully measure the static water level, vertical rise, and pipe lengths to ensure accurate TDH calculations.
  2. Pipe Selection: Choose pipe materials and diameters that minimize friction loss, such as PVC or HDPE with larger diameters.
  3. Fitting and Valve Selection: Minimize the number of fittings and valves in the system, and select components with low-friction characteristics.
  4. Pump Selection: Choose a submersible pump that is properly sized and matched to the TDH requirements of the system, ensuring optimal efficiency and performance.
  5. Regular Maintenance: Regularly inspect and maintain the piping system, fittings, and valves to prevent increased friction loss due to scale buildup, corrosion, or other factors.
  6. Monitoring and Optimization: Continuously monitor the system’s performance and make adjustments as needed to maintain optimal efficiency and water delivery.

Conclusion

The submersible well pump head is a critical parameter that must be carefully considered when designing and installing a water collection system. By understanding the components of TDH, accurately calculating the friction loss, and implementing strategies to optimize the system, you can ensure the efficient and reliable operation of your submersible pump, ultimately delivering water to your desired location with the desired flow and pressure characteristics.

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