Engineering resources: 

Dimension drawings: rasj40_drwg_dim_imp.pdf
Assembly drawings: rasj40_drwg_assmbly.pdf
Parts lists: rasj40_tab_partslist.pdf 

Two figure-eight lobe impellers mounted on parallel shafts rotate in opposite directions. As each impeller passes the blower inlet, it traps a finite volume of air and carries it around the case to the blower outlet, where the air is discharged. With constant speed operation the displaced volume is essentially the same regardless of pressure, temperature or barometric pressure. Timing gears control the relative position of the impellers to each other and maintain small, but defined, clearances. This allows operation without lubrication being required inside the air casing.

rotary_lobe_blwr_princ.pdf

Warranty Info: gts_5001_020107.pdf

• Casing-The blower casing is of one piece close-grained cast iron construction with separate headplates. The casing is suitably ribbed to prevent distortion under the most severe operating conditions and incorporates the ROOTS Whispair feature for reduced pulsation, noise and horsepower levels
• Impellers-The impellers are made from ductile iron with a tensile strength of 60,000 PSI. They are statically and dynamically balanced by removing metal from the impeller body, and operate without liquid seals or lubrication
• Shafts-The blower shafts are alloy steel forgings flange connected to the impeller body with high-tensile socket head capscrews. Labyrinth seals are machined into the shafts to minimize air leakage
• Timing Gears-The impellers are timed by a pair of accurately machined forged steel gears that operate in an oil bath. The wide-faced spur gears are manufactured to AGMA standards, and are carburized and ground with a hardness of 58-60 Rc. On 1000J frame size units, the gears are secured to the shafts by a taper fit. Larger sizes use a taper locking device providing an easily adjustable and releasable mechanical shrink fit. No shaft-weakening keyways or locking pins are required
• Bearings-The impeller/shaft assemblies are supported at each end by double row spherical roller bearings designed for long life. The thrust end bearings are fixed to control the axial location of the impeller assembly in the unit. An inboard bearing is used on 1000J thru 1400J frame size V-belt driven blowers to minimize drive shaft stresses
• Pressure Lubrication-The bearings and gears are lubricated by a positive pressure lubrication system completely mounted and piped on the blower unit. The lube system consists of an integral direct-driven oil pump, distribution piping, oil sump in the bottom of the gear housing, suction strainer, relief valve, oil pressure gauge, low oil pressure safety switch and oil cooler. Bearing life is extended by up to 50% through the use of cooled, pressurized lubrication. Splash Lubrication-The bearings and gears are splash oil lubricated. Gear end oil is metered through an orifice into a secondary sump under the gear, and is fed into the bearings through specially designed leaders. On the thrust end, bearings are splash lubricated with an oil slinger inside a single splash-lube cover. All oil reservoirs have visible oil level gauges
• Testing-Each ROOTS rotary blower is given a complete mechanical run and one-point flow test at full speed and pressure to ensure mechanical integrity and verify performance. The units are operated at elevated pressure rise for a minimum of one hour after temperatures have stabilized. Flow, pressure and temperature readings are logged during the test, and each air blower must meet suitable vibration levels in three different planes before being certified as acceptable.