BOOK IN SERIES
Figure 4.31
Figure 4.28
Vane pumps are usually set to rotate clockwise . Depending on the manufacturer ( the revolution is usually limited by the position of the pins ), anticlockwise revolution occurs by rotating the unit made up of vanes , stator and rotor ( the direction of the revolution in all types of pump is viewed by the shaft end ).
Figure 4.32
Figure 4.29
The balance of vane pumps is made possible by two diametrically opposed and mutually connected outlets and as many inlets . In this manner , the radial forces acting on an outlet are offset by the forces acting on the other ( Figures 4.30 and 4.31 ). As a result , the hydraulic thrust counterbalance most of the radial unbalance and it promotes the dimensioning reduction of bearings .
The unit ( Figure 4.32 ) made up of vanes , rotor , stator , bushes and control heads is usually referred to as ‘ cartridge ’ ( Figure 4.33 ).
Figure 4.33
Figure 4.30
Bushes and heads , found on both sides of the rotor / stator unit , guarantee an adequate suction / distribution of the fluid and the axial balance of the system .
In particular , brass intermediate bushes or wear plates , as well as distribution slots , distribute through splines the thrust fluid over the bases of each vane and ( in pin or intravane vanes – see later on ) in their clearances . The pressurised fluid flows into the two basins , fitted with proper seals and an antiextrusion ring , in the internal parts of the pressure plates , that channel it into the splines of the bushes ( Figure 4.34 ).
64 Global MDA Journal may 2018