Centrifugal pump classification, it is based on different structural characteristics and divided. First, according to the number of working impeller to classification 1, single-stage pump: that is, there is only one impeller on the shaft. 2, multi-stage pump: that is, there are two or more impellers on the pump shaft, then the total pump head is the sum of the lift produced by n impellers. Second, according to the pressure of work to classify 1, low-pressure pump: pressure less than 100 meters of water column; 2, the pressure pump: pressure in the water column between 100 ~ 650 meters; 3, high-pressure pump: pressure higher than 650 meters water column. Third, according to the classification of the impeller water way 1, one side of the water pump: also known as single suction pump, that is, only one inlet on the impeller; 2, bilateral water pump: also known as double suction pump, that is, both sides of the impeller has a water inlet. Its flow rate is double that of a single suction pump, which can be approximated as two single-suction pump impellers placed back-to-back together. Fourth, according to pump casing combined with the form of classification 1, the level of open pump: that is, through the axis of the horizontal plane with a joint seam. 2, the vertical joint pump: that is, the junction plane and the axis of the vertical. Fifth, according to the location of the pump shaft to classification 1, horizontal pump: pump shaft is located in a horizontal position. 2, vertical pump: pump shaft is located in the vertical position. Six, according to the impeller out of water leads to the way out of the room classification 1, volute pump: water from the impeller, directly into the helical shape of the pump housing. 2, guide vane pump: water from the impeller out into the guide vane set outside it, and then into the next level or into the outlet pipe. Usually we say that a pump is a multistage pump, which means how much the impeller. According to other structural features, it may be horizontal pump, vertical joint surface pumps, vane pumps, high pressure pumps, single-inlet pumps and so on. So according to different, the name is not the same. In addition, can also be classified according to use, such as pumps, pumps, condensate pumps, ash pumps, circulating pumps, etc.