| type |
vane |
positive displacement |
| centrifugal pump |
vortex pump |
reciprocating pump |
rotoring pump |
| main part |
impeller and body |
impeller and body |
piston and cylinder |
rotor and stator |
|
acting theory |
Impeller rotating produce centrifugal force and causes the liquid energy increase, pump body spiral (guide), diffuser make partial velocity turn into stress energy. |
Impeller rotating produce centrifugal force causes the liquid form radial vortex, and between the blades formed longitudinal vortex, make the fluid increase energy in many times repeatedly |
piston reciprocating motion, makes pump working cubage clearance changes in cylinder, pump valve control liquid one-way inhaling and exhaling, forming work cycle, causes the liquid energy increase |
Rotor rotating conveys liquid rely on the working volume change between the staror, causes liquid energy increase |
|
性
能 |
1 |
Large flow and evenly (stable), and head change |
small flow and evenly, change with the head |
small flow and unevenly(impulse), not change with head |
small flow and evenly(small impulse), not change with head |
| 2 |
head determines the impeller external diameter and rotating speed |
same with centrifugal pump |
large head, and decide pump itself power, intensity and sealing |
same with reciprocating pump |
| 3 |
The head and the shaft power and flow exist corresponding relation, head reduces with flow increasing, shaft power increases with flow increasing |
The head and the shaft power and flow exist corresponding relation, head reduces with flow increasing, shaft power reduces with flow increasing |
The head has nothing to do with flow, flow reduces with head increasing, shaft power changes with head and flow change |
same with reciprocating pump |
| 4 |
shorter sucting height, easy cavitation |
shorter sucting height, open type has sekf-scution performance |
higher suction height, hard to cavitation, with self-suction ability |
shorter sucting height, will produce cavitation |
| 5 |
In the low flow, efficiency is low, but in design point,efficienct is higher than large pump efficiency |
in low flow, it is higher than centrifugal pump, less than positive displacement pump |
higher efficiency, can maintain higher value under different head and flow |
lower efficiency under low flow, and it reduces with the head increasing |
| 6 |
转速高high rotating speed |
转速较高higher speed |
转速低low speed |
转速较低lower rotating speed |
|
operation and adjustment |
Before starting must infuse the pump and closed outlet valve. Using outlet valve or change speed adjustment, but unfavorable operating at low flow |
Start-up must open the outlet valve, need not the outlet valve adjusting, using bypass adjustment |
Start-up must open the outlet valve, need not the outlet valve adjusting, using bypass valve adjust, change speed and piston travel adjustment |
Start-up must open the outlet valve, need not the outlet valve adjusting, using bypass valve adjusting |
|
structural feature |
Simple and compact structure, easy installation and maintenance, cover small area, small basic, can direct connect with motor |
same with centrifugal pump |
Complex structure, many wearing parts, maintenance is trouble, covers big area, large foundation |
same with reciprocating pump |
| applicable scope |
Large flow, low head, small liquid viscosity, and is suitable for conveying soliquoid and dirty liquid |
low flow, low head, small liquid viscosity, is not suitable for conveying dirty liquid |
lower flow, high head, large liquid viscosity, is not suitable for conveying dirty liquid |
lower flow, high head, large liquid viscosity, is not suitable for conveying non-lubricating liquid and dirty liquid |
