How to Choose A Water Pump

1. Selection Method

The flow of the water pump, that is, the water output, generally should not be too large, otherwise it will increase the cost of purchasing the water pump. It shall be selected as required. For example, the self-priming water pump used by the user's family, the flow shall be smaller as far as possible; For example, the submersible pump used for irrigation can be appropriately selected with larger flow.

Figure 1: Water pump.

1.Water pumps should be selected according to local conditions. There are three types of commonly used agricultural water pumps: centrifugal pump, axial flow pump and mixed flow pump.

The centrifugal pump has high lift but small water output, which is suitable for mountainous areas and well irrigation areas. Axial flow pump has a large water output, but the lift is not too high, which is suitable for use in plain areas. The water output and head of mixed flow pump are between centrifugal pump and axial flow pump, which is suitable for use in plain and hilly areas.

Users should choose the pump according to the local conditions, water source and water lifting height.

2.The water pump shall be properly selected for exceeding the standard. After determining the type of water pump, its economic performance shall be considered, and special attention shall be paid to the selection of pump head, flow and supporting power. It must be noted that the water-lift indicated on the label of the pump is different from the outlet water-lift in use, because there will be a certain resistance loss when the water flows through the water delivery pipe and near the pipeline. Therefore, the actual water-lift is generally 10% - 20% lower than the total water-lift, and the water output is correspondingly reduced. Therefore, in actual use, it can only be estimated according to 80% ~ 90% of the lift and flow indicated on the label. The matching power of the water pump can be selected according to the power indicated on the label. In order to make the water pump start quickly and use safely, the power of the power machine can also be slightly greater than the power required by the water pump, generally about 10% higher; If the power is available, the matching water pump can be selected according to the power of the power machine.

3.Strictly follow the procedures to purchase water pumps. The "three certificates" shall be verified when purchasing, namely, agricultural machinery promotion license, production license and product inspection certificate. Only when the three certificates are complete can the purchase of obsolete products and inferior products be avoided.

2. How to Judge How Many Pumps are Needed

Figure 2: How mangy pumps we need?

1.Generally, normal operation only need one water pump. Because one large pump is equivalent to two small pumps working in parallel (referring to the same head and flow), and the efficiency of the large pump is higher than that of the small pump, it is better to choose one large pump instead of two small pumps from the perspective of energy saving. However, in the following cases, two pumps can be considered for parallel cooperation: the flow is large, and one pump cannot reach this flow.

2.For large pumps requiring 50% standby rate, two smaller pumps can be used for operation and two for standby (four in total).

3.For some large pumps, the pumps with 70% flow requirements can be selected for parallel operation without standby pump. When one pump is overhauled, the other pump is still responsible for 70% of the production.

4.For pumps that need 24-hour continuous operation, three pumps shall be standby, one for operation, one for standby and one for maintenance.

3. How to Distinguish Quality of Water Pumps

A photo about water pump MP20 from Okmarts

Figure 3: High quality water pump from Okmarts.

1.The product packaging of the original pump or supporting manufacturer is generally standardized, with clear and regular handwriting, and detailed product name, specification and model, registered trademark, factory name, address and telephone number; The packaging of counterfeit parts is generally rough, and the factory address and name are not clearly printed.

2.The qualified water pump has smooth surface and good workmanship. The more important the spare parts are, the higher the processing accuracy will be, and the more strict the anti rust and anti-corrosion packaging will be. When purchasing, if the parts are found to have rust spots, or the rubber parts are cracked, lose elasticity, or the journal surface has exposed processing lines, they should not be original accessories.

3.The appearance of inferior water pump is sometimes good. However, due to poor manufacturing process, it is easy to be damaged. When purchasing, you can see the quality of the accessory process by observing the concealed parts such as the edges and corners of the accessories.

4.Some water pumps are renovated with waste parts. At this time, the old paint can be found as long as the surface paint of the parts is removed. It is better not to use such pumps.

5.When the purchased parts are installed on the vehicle, it depends on whether they can be matched with other parts and have good matching. Generally, the original parts can be well allocated to the vehicle, while the inferior parts are difficult to coordinate with each other due to poor workmanship and large processing error.

6.In order to ensure that the assembly relationship of the water pump meets the technical requirements, some regular parts are coated with assembly marks to ensure the correct installation of accessories. If there are no marks or the marks are illegible, they are not qualified accessories.

7.Normal water pump assemblies and components must be complete to ensure smooth loading and normal operation. If small parts on some assemblies are missing, it is easy to start loading, which may be counterfeit parts.

8.Some important accessories, especially assemblies, are usually delivered with instructions and certificates to guide users in installation, use and maintenance. Counterfeit assemblies generally do not have detailed installation instructions to guide these.