First determine the specific type of high lift self suction pump, using what series of high lift self-priming pump selection, can according to the actual conditions needed for maximum flow flow, if the head is determined, according to the vertical height of the elbow and the horizontal distance and transportation, pipeline loss can calculate the required lift, magnified 5% - 10% margin values for the required lift, the main parameters of the two performance in spectrum or a series of characteristic curves to determine the specific type.
The pump characteristic curve, the required flow value found in the abscissa, required lift value found on the ordinate, respectively from two upward and to the right line or horizontal line, two line intersection falls in the curve, the high lift pump is to choose the self-priming pump, but this the ideal situation is generally not small, usually meet the following conditions:
1. The points above the curve, which shows that the flow to meet the requirements, but the head is not enough, at this time, if the head is not much difference, or a difference of about 5%, can use, if the head of a lot of difference, then select larger lift pump. Or try to reduce the loss of pipeline resistance.
2. Below the intersection in the characteristic curve, the pump characteristic curve within the fan-shaped ladder on the initial set of this model, and then lift the difference, to decide whether to cut the impeller diameter, if the head difference is small, do not cut, if the head is big, then according to the required Q, H, and ns, according to the cutting formula, cutting impeller diameter, if the intersection does not fall within the fan-shaped trapezoid, to be elected head of smaller pumps.
The above is the high head self suction pump flow head measurement method, in addition to choose high lift pump, sometimes need to consider the production process requirements, the use of different shapes Q-H characteristic curve.
