1,、 Types of water pumps

There are different options for agricultural irrigation pumps in different regions, and there are three main types of agricultural pumps available: mixed flow pumps, centrifugal pumps, and submersible pumps. The flow rate and head of a mixed flow pump are between those of a centrifugal pump and an axial flow pump. Small size, light weight, high efficiency, simple structure, easy to use, and easy to maintain. The conveying medium is clear water or similar to clear water, suitable for agricultural drainage and irrigation in areas with abundant surface water sources in the south. Centrifugal pumps work by utilizing the rotation of impellers to cause centrifugal motion in water. There are many models to choose from, and the range of flow and head options is also wide, making it a widely used water pump in agriculture. Low lift centrifugal pumps can be selected in plain areas, moderate lift pumps can be selected in hilly areas, and multi-stage centrifugal pumps with higher lift pumps can be used in high-altitude areas. Users need to make purchases based on local conditions, water sources, and lifting heights. Submersible pumps are suitable for pumping water from deep water wells and are mainly used for irrigation in plain areas such as North China where surface water is scarce, as well as in high-altitude mountainous areas.

2,、 Head of water pump

The so-called head refers to the required pressure, not a single lifting height, and it is particularly important to clarify this when choosing a water pump. The head of the water pump is approximately 1.15-1.20 times the lifting height. If the vertical height from a water source to the water usage point is 20 meters, the required lift is approximately 23-24 meters. When selecting a water pump, the head on the pump nameplate should be close to the required head. In this case, the efficiency and use of the water pump will be more economical. But it is not necessarily required to be equal. Generally, as long as the deviation does not exceed 20%, the water pump can work in a more energy-efficient manner.

Choosing a water pump with a head much lower than the required head often fails to meet the user's wishes. Even if it can pump water, the water volume will be pitifully small, and it may even become a useless "idle pump". Is it better to purchase a water pump with a higher head? Actually, it's not like that. If a high head pump is used for a low head, it will result in excessive flow, causing the motor to overload. If it runs for a long time, the temperature of the motor will rise, and the insulation layer of the winding will gradually age, even burning out the motor.

(1) Low head, use a regular centrifugal pump. The water hose has a micro spray head, and the working pressure of the hose is generally below 10 meters and 20 meters, plus pipeline losses, the water pump head is 15-25 meters. The working pressure of ordinary micro sprinkler or drip irrigation is around 20 meters, and the pump head can be selected from 25-40 meters. For small households (3-10 acres), the "one pump, one pipe" mode is adopted, with optional power of 1.1-2.2 kilowatts, caliber of 25-40 millimeters, and head of about 15 electric motor water pumps. In the absence of power lines, gasoline engine water pumps can be used.

(2) Moderate head, use sprinkler pump. Generally used for field sprinkler irrigation, with irrigation units of around 50 acres and a pump head of 45 meters; The irrigation unit is around 150 acres, and the pump head is selected to be 55 meters.

(3) High head, choose multi-stage water pump. Generally used for sprinkler irrigation in mountainous areas, the head calculation is also simple, that is, the plain head+the relative height of the mountain. For example, if the mountain is about 50 meters high, the pump head needs to be about 100 meters. Ordinary centrifugal pumps have low efficiency when used for high lift, so they are not suitable for use. When the head is greater than 55 meters, a multi-stage pump can be selected, which is composed of multi-stage impellers connected in series, and the head can reach more than 200 meters, while the efficiency is still the same as that of a single-stage impeller and will not decrease.

3,、 Pump flow rate

The flow rate of the water pump, that is, the water output, has a rated flow range for each type of micro spray or drip irrigation. The installation of micro spray or drip irrigation requires a flow rate, which is the total flow rate required by multiplying the flow rate of each micro nozzle or drip head by the expected number of installations. It is generally not advisable to choose too large, otherwise it will cause problems such as pipe bursting in the irrigation system and increase the cost of purchasing water pumps.