Sliding vane rotary vacuum pumps

Operating principle

The MAPRO® vacuum pumps, BV series, are rotary vane machines, oil recirculating type. In these vacuum pumps a cylindrical rotor turns eccentrically in a cylindrical stator of a larger diameter: the free space left between stator and rotor is half-moon shaped. Three slots are milled in the rotor and stratified plastic blades slide freely into the slots. The blades, as the rotor turns, are forced out against the cylindrical wall of the stator by centrifugal force, so creating individual “cells” whose volume changes continuously during the rotation.

Constructional features

The main construction features of the MAPRO® vacuum pumps, BV series, are the following.

• casing of the pump (stator and heads) made of cast iron; rotor in carbon steel; blades in light stratified material;
• oil tank-separator made of aluminium alloy;
• sealing between the static parts of the pump by O-rings; between the pump body and the tank-separator by gaskets;
• shaft sealing by lip seals in Viton (FKM);

Hub between pump body and electric motor made of aluminium alloy; the flange mounted electric motor is bolted to the hub and the vacuum pump rotor is driven by a flexible coupling between motor-shaft and pump rotor-shaft; differently from all the other models, the pump BV20 is manufactured in the so-called “close coupled” version; i.e. the front shield of the electric motor is also

• the front head of the pump and the vacuum pump rotor is fitted directly onto the motor shaft extension.


The main advantages of using the MAPRO® oil recirculating type vacuum pumps are:

• easy installation;
• simple and economic maintenance;
• low noise level;
• unchangeable and high volumetric efficiency;
• pulsation free sucked air flow;
• no vibration;
• suitability for use in many industrial applications;
• high water vapour tolerance if the pump is fitted with ballast valve.


A complete line of accessories is available which includes, among other things:

• suction filters;
• vacuum meters and vacuum switches;
• manual and automatic shut-off valves;
• vacuum level regulators;
• pipe-holder fittings.

The MAPRO® Sales Department, in synergy with its own Technical Service, is able to study and propose, on the basis of customer requests, equipped machines in order to best respond to the specific needs and peculiarities of use.


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