(1) in the open multi-stage centrifugal pump
Open or half open in high pressure multistage diesel pump is generally adopts the volute pump body, pump casing in main shaft centerline plane separately, the pump according to the main shaft is installed in the open in different points level and vertical open type two kinds, it is each impeller has a corresponding volute suction chamber and pressure out of the room, which is equivalent to a few single stage volute pump assembly work on the same shaft series.

This form of self-priming diesel pump because of the suction and discharge outlet directly cast on the pump body, so maintenance, do not need to be removed, the axial force of the population pipeline balance as long as the pump shell is removed, the rotor can be removed.

The impeller is usually arranged symmetrically with even numbers to eliminate unevenness, so there is no need to set up another axial force balancing device.

This pump with the same performance of the sectional centrifugal pump, the flow is generally large, high head, so it is mainly used for urban water supply, its large volume, casting and processing technology requirements are higher.

Because of it steam boiler water supply, mine drainage and oil pipelines.

Its flow rate is 450-1500m3 /h, the head is 100-500m, the highest outlet pressure can reach 18MPa.
 
(2) segmented multi-stage centrifugal pump
The segmented multistage centrifugal pump is a vertical split multistage diesel pump, which is composed of a front section, a back section and a number of middle sections, and is bolted together as a whole.

The two ends of the pump shaft are supported by bearings, the pump shaft is equipped with a number of impellers in the middle, between the impeller and the impeller with shaft sleeve positioning, the outer edge of each impeller is equipped with the corresponding guide wheel, in the front and the middle of the inner arm and the impeller is easy to touch the place with a sealing ring.

The impeller is generally single suction, the suction population is toward one side, and the impeller is connected in series on the shaft according to the single suction impeller population direction.
In order to balance the axial force, a balance disc is installed behind the stage impeller, and a balance pipe is communicated with the front segment.

The rotor can move around when it is working, and the rotor is automatically maintained in the balanced position by the balance plate.

The shaft seal device is symmetrically arranged in the front section and the rear section of the shaft extension part of the pump. The representative work of this form is the CYZ centrifugal pump.