Irrigation Pumps

Detailed introduction of irrigation pumps

Irrigation pumps are the core equipment of irrigation systems such as agriculture, gardens, and greenhouses. They are mainly used to pump water from water sources (such as rivers, wells, reservoirs, etc.) and transport it to irrigation pipe networks to ensure that crops receive uniform and efficient water supply. According to different water source conditions, irrigation methods and system requirements, the types, performance and applicable scenarios of irrigation pumps are also different.

I. Main types and characteristics of irrigation pumps

1. Centrifugal pumps

Centrifugal pumps are one of the most common irrigation pumps. They generate centrifugal force through the rotation of the impeller to pressurize and transport water. They are characterized by large flow and moderate head, and are suitable for pumping surface water (such as rivers and ponds). The head of a single-stage centrifugal pump is generally 10 to 100 meters, and that of a multi-stage centrifugal pump can reach more than 200 meters, which is suitable for field sprinkler irrigation or long-distance water delivery.

2. Submersible pumps

The motor of a submersible pump is integrated with the water pump, which works completely immersed in water and can be started without water diversion. Its advantages are low noise and high efficiency. It is suitable for deep well (10~300 meters) pumping and is often used in conjunction with drip irrigation and micro-irrigation systems.

3. Axial flow pump

The water flow direction of the axial flow pump is parallel to the pump shaft. It is characterized by a very large flow rate (up to tens of thousands of cubic meters/hour), but a low head (usually less than 10 meters). It is suitable for large-scale rice field irrigation or drainage.

4. Mixed flow pump

The mixed flow pump combines the characteristics of centrifugal pumps and axial flow pumps. The water flow is oblique, and the flow rate and head are between the two. It is suitable for channel water irrigation in plain areas.

5. Self-priming pump

The self-priming pump can automatically empty the air when starting, without filling and diverting water. It is suitable for mobile irrigation or frequent start-stop occasions, such as temporary irrigation of small farmland and orchards.

6. Deep well pump (long shaft deep well pump)

The deep well pump drives the impeller under the well through the long shaft. It is suitable for taking water from ultra-deep wells (more than 100 meters) and the head can reach more than 500 meters. However, the installation and maintenance are more complicated and it is mainly used for high-head irrigation in arid areas.

2. Key performance parameters of irrigation pumps

1. Flow rate (Q)

The flow rate refers to the amount of water delivered by the pump per unit time, usually expressed in cubic meters per hour (m³/h) or liters per second (L/s). The flow rate directly affects the irrigation area and irrigation speed, and needs to be reasonably selected according to the crop water demand and irrigation method.

2. Head (H)

The head refers to the height to which the pump can lift water, including the terrain height difference, pipeline friction loss and the working pressure of the sprinkler/drip irrigation belt. The total head is calculated as: total head = net head + pipeline loss + sprinkler pressure.

3. Power (P)

The power is divided into shaft power (the actual power required by the pump) and supporting power (the rated power of the motor or diesel engine). When selecting a water pump, the motor power should be 10%~20% greater than the shaft power to avoid overload operation.

4. Efficiency (η)

Efficiency reflects the energy consumption ratio of the water pump. High-efficiency water pumps can save electricity bills. The efficiency of ordinary centrifugal pumps is usually 60%~80%, while the efficiency of high-quality submersible pumps can reach more than 85%.

5. Speed (n)

Speed refers to the rotation speed of the water pump impeller, measured in revolutions per minute (rpm). Speed affects flow and head. High-speed water pumps usually have higher heads, but may also increase wear and energy consumption.

III. Selection Guide for Irrigation Water Pumps

1. Selection according to water source

Surface water (rivers, ponds): suitable for centrifugal pumps, axial flow pumps or mixed flow pumps.

Shallow wells (<10 meters): self-priming pumps or small submersible pumps can be selected.

Deep wells (10~100 meters): deep well submersible pumps are recommended.

Ultra-deep wells (>100 meters): long-axis deep well pumps are required.

2. Choose according to irrigation method

Sprinkler irrigation: requires higher pressure (2~4 bar), suitable for high-lift centrifugal pumps or multi-stage pumps.

Drip irrigation/micro-irrigation: requires stable low pressure, suitable for submersible pumps or low-pressure centrifugal pumps.

Furrow irrigation/flood irrigation: requires large flow, axial flow pumps or mixed flow pumps can be selected.

3. Choose according to energy

Stable power supply: electric centrifugal pumps or submersible pumps are the first choice.

In areas without electricity: diesel engine pumps or solar water pumps can be selected.

IV. Installation and maintenance of irrigation water pumps

1. Installation points

Solid foundation: The water pump should be installed on a flat and solid foundation to reduce vibration and noise.

Prevent air leakage in the water inlet pipe: The centrifugal pump needs to be filled with water before the first start, and the water inlet pipe should be well sealed to avoid cavitation.

Filter protection: The water inlet of the submersible pump and the self-priming pump should be equipped with a filter to prevent mud and sand from clogging the impeller.

2. Daily maintenance

Regularly check the bearing lubrication: Ensure that the bearing is well lubricated to avoid wear.

Clean the filter: prevent impurities from entering the pump body and affecting performance.

Winter antifreeze: When the pump is not in use, the accumulated water in the pump should be drained to prevent freezing and cracking.

3. Common fault handling

No water: Check whether the water inlet pipe is leaking and whether the impeller is blocked.

Insufficient flow: It may be due to filter blockage, insufficient speed or excessive head. The filter needs to be cleaned or the system parameters need to be adjusted.

Abnormal noise: It may be due to bearing damage or cavitation, and the machine needs to be shut down for maintenance.

V. Energy saving and intelligent irrigation optimization

Frequency control: Reduce energy consumption by adjusting the speed of the water pump to match the actual water demand.

Solar water pump: Suitable for areas without power grid, driven by solar energy, environmentally friendly and energy-saving.

Intelligent irrigation system: Combine soil moisture sensors and automatic controllers to achieve precise irrigation and reduce water waste.

Summary

The selection of irrigation water pumps needs to comprehensively consider water source conditions, irrigation methods, energy supply and system requirements. Reasonable selection, correct installation and regular maintenance can significantly improve irrigation efficiency, reduce energy consumption and extend equipment life. For large irrigation projects, it is recommended to consult professional engineers for system design and optimization.