Industrial inline duct fan ventilators,al ventila tube axial and vane axial blower fans. Sales of large industrial vaneaxial and tubeaxitors, fans and blowers.
Canadian Blower Company

Tri-Lobe Positive Displacement Blowers, due to rotor tips disposed at 120º on each rotor, cause the rotor set to be much more resistant to angular deflection along it's length, than two lobed rotor sets, which have lobe tips disposed at 180º each - this extra "stiffness" provides less deflection at any load, thus minimizing possible rotor contact with both the cylinder and it's sister rotor during operation.
Positive Displacement Blowers (of the "Roots" type design)  are highly developed standard production machines designed and adapted to find use in a wide variety of applications:
Pneumatic conveying of bulk materials: In suction or discharge pressure. Machine sizes range from small blowers installed in tank vehicles to very large ones used in pneumatic elevators for vacuum operated ship unloaders. The hourly capacity of such unloading installations is up to 1000 tons at present.

Pressurized aeration of basins in sewage treatment plants: Filter flushing blowers in drinking water production plants. Gas boosting blowers rated for internal static pressures of up to 25 bar. High vacuum boosters are equipped with special shaft seals.

Conveying of pratical all gases: found in the chemical, petrochemical, and metallurgical industries. Special designs are available to handle aggressive gases. Machines used in both conventional and nuclear power plants comply with the various categories of safety regulations.

Surgeless Blowers – High-pressure, low-volume blowers with a reduced tendency for “surging” even at severely reduced flowrates. This allows extreme turndown (low-flow) without significant pulsation. In axial flow ventilator the air must blow in line with the axis of rotation and there must be blades with space between them.