地址：Jiangyan Economic Development Zone, Taizhou
Selection and matching of agricultural water pump
The selection of agricultural water pump includes the selection and matching of water pump. The type selection refers to the rational selection of pump type according to the requirements of local irrigation and drainage. The matching refers to the rational matching of the power machine, transmission equipment, pipeline and pump. Reasonable selection of water pump is the precondition of correct use of water pump. The matching of water pump is suitable. It can reduce investment, reduce energy consumption, and improve the efficiency of irrigation and drainage. There are many kinds of pumps and different models. When selecting, we should start with the following two aspects.
I. selection of pumps
The key to select a pump is to select its head and flow reasonably. For farmland irrigation, it should be determined according to the natural and topographical conditions and the demand for production and utilization in each region.
1, pump parameter determination
When selecting the pump head, the actual lift and loss head should be included. In determining the actual lift, we should consider the water level changes, investigate the minimum water level and dry water level which may occur in the peak water use period to ensure the normal operation of the water pump.
The loss of lift and pipeline length, pipe diameter, pipe and pipe accessories of the type and quantity of other conditions, the value of the actual head (0.03~0.5), large head or large diameter for small value, and large value.
(2) flow rate;
For pumping water pump, the flow rate should be based on the actual amount of water used for agriculture, small irrigation area, often according to the drought and the crop water demand during the peak period of water to determine the irrigation flow, the water peak due to soil, crops and farming systems vary. The pump is mainly used for pumping water aquaculture ponds and ponds, considering the actual needs.
2, the type and number of pumps determined
After selecting the irrigation head and flow, we should seriously consider the type and number of pumps. Whether to choose centrifugal pump, axial pump or mixed flow pump, the main consideration of local topography, water, lift, irrigation and other factors. Centrifugal pump specific speed is 30~300r / min, lift, up to several hundred meters, the flow of small, good cavitation resistance, suitable for high water large reclamation area and well irrigation area; axial flow pump specific speed is 500~1200r / min, head of 4~l5m, a flow of centrifugal pump and mixed flow pump, but cavitation resistance poor, suitable for high water and low water into the pool, small fluctuations in the plain area; mixed flow pump specific speed of 300~500r / min, head of 4~25m, the larger flow, good cavitation resistance, suitable for high water is small, large fluctuations in the water into the plains and hilly areas.
Relatively speaking, the centrifugal pump is widely used because of its high lift and high efficiency. The power efficiency of the mixed flow pump is wider and the cavitation resistance is better. Therefore, it is preferred to the axial flow pump. In the selection, we should make full use of the local water power resources, and in areas where conditions permit, we should use water pump, water hammer pump and other water lifting tools as far as possible.
Medium and small pumps should use horizontal pumps whenever possible. The pump is simple in structure and easy to operate and manage. As for the number of units, the design should be determined by irrigation flow and scale. Usually large pump, high efficiency, can reduce the number of pumps, but not conducive to operation and comprehensive utilization. Of course, it does not mean that the more water pumps the better, generally should choose 2~4 units, absolutely not more than 10 units, should try to use the same type of pump, easy to operate, maintenance and management. If the number of units decided n Taiwan, the design flow of single pump Q (Q = Q total / N) can be calculated, the water pump caliber can also be estimated, and then from the pump product samples, refer to the pump performance table, select the appropriate pump.
When choosing a pump, we should consider the following factors: good performance, high quality, reasonable price, convenient purchase and transportation, especially the standardization, generalization and serialization of the same model. Select the brand, reputation, high quality products to ensure quality and reduce maintenance.
Two, the choice of matching power machine
Pumps and pumps supporting the general use of motor or diesel engine. In rural areas, the use of diesel engines is common because of insufficient power supply. The nameplate of most pumps is marked with the power that is matched with the power machine, and the power machine can be selected according to the power. If no matching power is indicated on the pump, the following method shall be determined.
1 、 matching with motor
Squirrel cage motors are widely used in medium and small pumps. In order to prevent the motor from overloading, its matching power is greater than the maximum shaft power of the pump. The choice of supporting motors is not the greater the better, so that not only increased input, but also the lack of motor load, the use of efficiency reduction, waste of energy.
2 、 matching with diesel engine
The choice of diesel engine mainly depends on its load characteristics (comprehensive measurement of economic and dynamic indexes) and speed and other technical parameters. In general, medium and small pumps should be equipped with high speed diesel engines (n > 1000r / min), and large water pumps should be equipped with low-speed diesel engines (n < 1000r / min).
Under normal circumstances, diesel engine power is 1.1~1.7 times the power of the pump shaft, big pump to take small value, small pump to take big value, namely: P pump less than 5KW, K=1.5~1.7; 5KW < P, pump less than 50KW, K=1.1~1.3. If a large selection of power unit operation in the load under the condition of insufficient, both energy consuming and expensive, and poor economy; if the matching power is too small, the unit operation in overload conditions, then the mechanical wear intensifies, affect the life of the engine, the power of difference. Therefore, according to the actual situation, select the matching power.
Three, the choice of power supply
Pumps according to the power supply of the motor, there is a three-phase power supply (380V) motor and single-phase power supply (220V) motor, in the purchase should pay attention to. A three phase motor pump can be selected by a user with a three-phase power supply, and the three-phase motor has stable performance and reliable use. And if only lighting