Guangdong Kaiping Dannai Pump Co., Ltd.
Pump Selection Guide: Systematic Matching of Flow Rate, Head, Medium and Material
Published Time:
2026-07-31
Proper pump selection is critical to ensure long-term stable system operation. Its core lies in the scientific matching of four factors: flow rate, head, medium and material.
1. Flow Rate (Q)
Flow rate refers to the volume of liquid passing through the pump per unit time, commonly measured in m³/h or L/min. Selection shall be based on the maximum flow rate required under actual working conditions. If only the normal flow rate is available, proper margin is recommended: 5% for large-flow low-head pumps and 10% for small-flow high-head pumps. Excessively high flow rate leads to energy waste, while insufficient flow rate fails to meet operating requirements.
2. Head (H)
Head represents the height the pump can lift liquid, measured in meters (m). Design head shall comprehensively consider vertical lift height, pipeline friction loss (including resistance from elbows and horizontal sections) and outlet pressure requirements. A 5%～10% increase above the calculated value shall be adopted as the selected head. Please note that the rated head marked on the nameplate excludes pipeline friction loss, which cannot be ignored during selection.
3. Medium Characteristics
Medium properties directly determine pump type selection. It is necessary to confirm medium name, density, viscosity, temperature, corrosiveness, solid particle content and particle size. Clean water can be conveyed by clean water pumps; media containing particles or long fibers adopt sewage pumps or open-impeller pumps. Centrifugal pumps are generally not suitable for high-viscosity media.
4. Material Selection
Materials for wetted parts are determined according to medium characteristics. For clean water, normal temperature and low-head working conditions, gray cast iron (HT200/HT250) is an economical option. Stainless steel shall be selected for corrosive media based on specific compositions: SS304 for mild corrosion environments, and SS316L for chloride-containing or strongly corrosive environments. Fluoroplastic or fluorine-lined pumps are recommended for highly corrosive media such as hydrochloric acid. Wear-resistant alloy or high-chromium cast iron is required for media with high sediment content.
Precise matching of the four factors enables long-term, reliable and efficient operation of the pump unit.
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