Page 167 - Practical Machinery Management for Process Plants Major Process Equipment Maintenance and Repair

Positive Displacement and Dynamic Blowers 149

Unless otherwise stated by the manufacturer, use the following values
in ft-lbs:

114 in. cap screw .................................... 12
5/16 in. cap screw ................................... 24
318 in. cap screw .................................... 42
112 in. cap screw .................................... 90

2. Weight of blower
3. Oil capacity: drive end and nondrive end
4. Lubricating oil required
5. Oil change interval

Care and Maintenance of Fans'

Large Fan Blower Maintenance

The use of large fans, or blowers, in petrochemical process, power
plant, and other industrial applications has experienced a tremendous
growth in the past decades. Much of the growth has been brought about
by the demand for cleaner air. Boilers, waste heat recovery equipment,
furnaces and related systems have produced increasingly hotter, more
corrosive and particulate matter-laden gases to be moved. With the han-
dling of more demanding gas in greater volumes have come larger and
faster fans, which must be considered an important part of the plant
maintenance load.
Heavy duty fans dealt with in the following section are used in two
major functions: Forced draft and induced draft. Forced draft fans are
used to push air through a furnace, boiler, or process apparatus. Induced
draft fans are exhaust fans which draw gases from the process-usually
pollution control equipment. Both types of fans are usually found with
one of four impeller arrangements, namely paddle wheel, radial tip, dou-
ble inlet airfoil, and single inlet fan. Figure 4-3 shows an exploded view
of the more common heavy duty single inlet fan. Figure 44 illustrates the
less common vaneaxial fan arrangement.

Fan Component Nomenclature

Heavy duty fans have impeller diameters up to 166 in. and may weigh
up to 10,000 lbs. Operating speeds range from 600 to 1,800 revolutions
per minute depending upon the fan system and its application. Figure 4-5

* Courtesy of Canadian BlowerlCanada Pumps Ltd., Kitchener, Ontario, Canada