High vacuum lobe blower air-ends RBS-AV series

Booster units for multi-stage vacuum systems

High vacuum rotary lobe blowers, RBS/AV series, are used to increase the capacity of primary vacuum pumps, operating at their minimum suction pressure (as a booster), along with a primary vacuum system (VP). It fits pressure level lower than 50 mbar(a).

Vacuum up to 0.001 mbar (a)
Flowrate up to 9,400 m³ / h

Technical Specifications
Product Description
Advantages

The RBS/AV series are rotary three lobe blowers used in vacuum installations as boosters in combination with primary vacuum pumps. They are used for applications where the final pressure request by the system is lower than 33 mbar absolute. Typically, these applications utilize liquid ring vacuum pumps (Robuschi RVS series), screw pumps, claw pumps, vane pumps or piston pumps as the primary vacuum system. The typical configuration of this system is vertical with the RBS/AV positioned up and the vacuum pump positioned down. Both are directly connected. In addition, it is fairly common to have a multiple stage system with two or more RBS/AV high vacuum blowers if the the suction pressure or the capacity requested exceeds the maximum values of the total RBS/AV’s range.

Construction

The RBS/AV series are composed of two conjugate rotors which rotate with tight clearances (hundredth of millimetre) in all positions inside a specially designed casing. This assures that gas is sealed within the casing without contact between the parts. The rotors are synchronized using high precision involute toothing, allowing for high rotational speed. The seal between the compression chamber and the bearing housings is made with labyrinth seals that prevent any oil aerosol from entering the compression chamber. The sealing between the compression chamber and the environment is ensured by O-ring seals in the FKM elastomer set between the ground surfaces. Robuschi’s specialized rotor grinding manufacturing process allows for tight dimensional tolerances. The body is composed of cast iron, while the rotors use nodular cast iron. If the vacuum is used for corrosive gases or vapours, the parts that come in contact with them can be coated in a stainless nickel alloy.

Operation

The RBS/AV series blowers have to be used in series with a primary vacuum system according to the diagram and they can not be used in the field of pressures higher than 50 mbar absolute (for these applications it is possible to employ the ROBUSCHI RB-DV air injection blowers) because of the too high absorbed power as well as rotor and casing overheating. The RBS/AV blower has to be started only after the VP primary vacuum system has reduced the absolute pressure of the plant to a value lower than 50 mbar.