• Rotary lobe blowers with pressure to 1,000 mbar (g), vacuum to 100 mbar (a) & air flow to 25,000 m³/h
• Wide range of models, sizes, options, and configurations available
• Optimal performance and maximum uptime with consistent quality and reliability in every application

The range of Robuschi Rotary Lobe Blowers has been reinvented, focusing on delivering exacting customer requirements. 

We launch the new Robox blower unit concept, a cutting-edge solution that can accommodate rotary lobe and screw technologies to provide users with greater choice than ever before in helping meet their industrial air and gas needs.

With the new Robox, the difference between lobe and screw technology is reduced to just a few components. This makes it simpler than ever to change from one technology to another and embraces the ongoing shift in mindset from capital investment to total cost of ownership.

Robuschi rotary lobe blowers are available at varying pressures above atmospheric up to 1,000 mbar (g) and for vacuum duties up to 100 mbar (a) along with maximum air flow of 25,000 m³/h.

Because of the wide range of models, sizes, options, and configurations available from Robuschi, there is a rotary lobe blower that can provide solutions for most industrial applications. These blowers can operate in pressure and vacuum, and can be equipped as a complete package, with customisation according to specific industrial technical requirements and providing optimal performance and maximum uptime with consistent quality and reliability in every application.

There is a rotary lobe vacuum product for just about any industrial requirement.

Functionality of the “Roots” Positive Displacement Blowers

The air flow depends on the position and direction of the rotors. The typical installation provides a constant air flow, and that the rotational direction is dependent on the “Roots” blower design. As a side note, the Roots blower design is enduring and durable. The rotary positive air blower was designed in the 1850s and patented in 1860 by brothers Francis and Philander Roots and the Roots name has remained as the description of the design.

The basic principle is as follows: the process starts with air flowing from the inlet port into the element chamber. The timed rotation of the rotors against the wall of the chamber creates so-called “air flow direction”. There is still atmospheric pressure in these chambers. 

As soon as the first lobe passes the opening to the pressure side, the system pressure is adjusted. This is called isochoric compression. The rotors seal each other off to the inside, which prevents a change of pressure.

Compression Principle

The performance of the compression principle is as follows. Positive displacement blowers operate using the isochoric compression principle, also known as external compression. The pressure increase is achieved by intermittently transporting a gaseous medium (e.g. atmospheric air) into a system. By forcing the medium from atmospheric conditions into a system with a given resistance (e.g. a water column, distribution network), the relevant pressure increase is achieved. The blower will operate at a controlled output level to overcome this resistance. 

Positive displacement blowers are made up of two or three conjugate lobe shaped rotors which rotate inside a pre-machined chamber. The chamber is sealed by the rotating rotors. The rotors are synchronised by means of a timing 1:1 gear ratio, positioned at the end of the shafts. Bearings are positioned externally to the compression chamber with an oil lubricated system. The drive shafts have labyrinth style oil seals, so called because of the labyrinth of grooves that the oil must pass through. The splash lubrication system uses a fine mist of oil for lubrication.

Our products include vacuum pumps, screw compressors, and lobe compressors, and we can deliver the rotary lobe compressor to meet and exceed your application requirements. Our systems have a reputation for being low maintenance.

How the Robuschi Screw Blower Airend Works?

The Robuschi oil-free  screw blower airend is a positive displacement machine with rotary motion, also known as “helical screw” compressor. 

It delivers constant flow (volume) and variable pressure, which means that at a given speed (rpm), the compressor airend always supply the same amount of air, independently by the pressure variation. 

The screw blower airend consists of a pair of helical profile rotors (one male rotor with 3 convex lobes and one female rotor with 5 concave lobes or “flutes”), contained in a casing. 

The rotors turn in opposite direction maintaining precise alignment by means of timing; meshing they form a series of working chambers between the rotors and the casing wall. 

The gas is sucked from the intake side (suction), trapped between the rotors and the casing (radially) and the cover (axially), transported to the compression side (discharge) where the working chamber shrinks, and compressed.     The internal compression leads to supply a steady, non-pulsating air flow, minimizing vibration and maintenance and maximizing lifetime. 

Due to the fact that there is no oil for sealing (oil-free screw), the rotors have very precise and small tolerances to maintain a very small air-gap between the two in order to guarantee optimal performance without touching each other.