Bare Shaft Positive Displacement Blowers

HIBON continues to pioneer in the design and manufacture of the highest quality and truly innovative Positive Displacement Blowers for more than 100 years.

What are the different types of air/gas blowers?


At its most basic level a blower is a machine that draws in air at an inlet and pushes air out as a steady stream at the outlet. 
There are largely two categories of blowers: impeller based and positive displacement. Impeller based blowers have fins that radiate outwards from a rotating central axis. 
Positive displacement blowers use a mechanism of filling and emptying chambers at the inlet and discharge side, respectively, to create flow. 
The fundamental difference between the two is that impeller based blowers have output flow that varies with pressure whereas positive displacement blowers have a more constant output flow regardless of change in pressure.

The impeller is generally called rotors or lobes.


bare shaft positive displacement blowers hibon nx vtb siav injection air

Examples of bare shaft positive displacement blowers

HIBON NX series

Principle of operation of positive displacement blowers

Positive displacement blowers incorporate two three-lobe rotors or two two-lobe rotors. One of the rotors is driven by the drive shaft. The other rotor is maintained in the correct phase relation by timing gears. The timing gears and the bearings on the rotors and drive shaft are lubricated by oil in the drive end cover and non-drive end cover.

During operation, the inlet gas stream to be pumped/compressed enters the blower at the inlet.
As the two contra-rotating rotors turn, the inlet gas is trapped in the conveying chamber formed between the rotors and the blower-body, and is eventually forced out of the blower at the outlet. (Discharge side)
The volumetric flow is dependent on the size of the conveying chamber and the speed of rotation.
Rotary Lobe blowers "Roots" type have no lubrication or oil in contact with the air and therefore are useful for applications where the delivered air must be free from contaminants.

Positive Displacement Blowers can be available in eight different positions depending flow direction:
Shaft position
Direction of rotation

When the blowers are supplied in bare shaft positive displacement blowers form, you must connect  your own coupling or belt drive system to the drive shaft in order to operate the blower. It is completely different from a "package unit" integrating motors, silencers, acoustic enclosure, filters and other components.


Bare Shaft Positive Blowers are suitable for pressure or vacuum operation. 

The blowers are suitable for pumping/compressing ambient air and no-flammable gases, gas mixtures and dusts.
They are often used for pneumatic conveying, aeration, fluidisation, filter cleaning. 
They can also be used directly on trucks for dry-bulk transfer. 

HIBON: Widely recognised as Manufacturer Of Positive Displacement Blowers

Since 1867, when the first "Roots" blowers with two lobes were presented at the Paris exhibition, positive displacement blowers have made their way to a place of low gas compression. They are ideally located between fans (very low pressure) and compressors (high pressure).

In 1945, Hibon became the French leader in the manufacturing of positive displacement blowers and supplied a wide range of blowers. Our positive displacement blowers provide air/gas volumes at varying pressures above atmospheric for numerous markets and applications.

Our Bare Shaft Positive Displacment Blowers can be incorporated directly by end-user or OEM into their own product solutions and package units.

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