The basic principle of water pump selection and step 2

The basic principle of water pump selection and step 2 

1. List basic data:
1. Characteristics of media: medium name, specific gravity, viscosity, corrosion, toxicity, etc.
2. The diameter and content of the particles contained in the medium.
3, medium temperature (℃)
4. The required flow.
In general industrial pump can ignore leakage in pipeline system in process flow, but it must consider the influence of process change on flow.If the submersible pump USES open channels, the leakage and evaporation must be considered.
5. Pressure: the pressure of the suction tank, the pressure of the drain tank, the pressure drop in the piping system (head loss).
6. Pipe system data (pipe diameter, length, type and number of pipeline accessories, the geometric elevation of the suction tank to the ballast tank).
Device characteristic curves should be made if necessary.
When designing the piping, the following should be noted:
A, reasonable choose pipe diameter, pipe diameter is big, under the same flow rate, liquid flow velocity is small, small resistance loss, but the price is high, the pipe diameter is small, can lead to resistance losses increase sharply, increase the selected pump lift, installed with power increasing, the cost and operation cost are increased.Therefore, the technical and economic aspects should be taken into consideration.
B. The discharge pipe and its pipe joints shall consider the maximum pressure that can be borne.
C, pipeline layout should decorate straight pipe as far as possible, try to reduce the attachment and try to narrow the pipe length, pipe must turn, elbow bend radius should be 3 ~ 5 times the diameter of the pipe, as much as possible Angle is greater than 90 ℃.
D. The discharge side of the pump must be installed with the valve (ball valve or globe valve, etc.) and the backstop valve.The valve is used to adjust the operating point of the pump. The backstop valve can prevent the pump from reversing when the liquid is flowing back, and the pump can avoid the blow of the water hammer.(when the liquid reverses, it causes a huge reverse pressure, which damages the pump.)
2. Determine the flow head.
Determination of flow
A. If minimum, normal and maximum flow is given in the production process, the maximum flow should be considered.
B. If only normal flow is given in the production process, the residual amount should be considered.