Fans and Blowers
Fans and Blowers
Fans and Blowers
CHAPTER 5
ME LAB 2
Axial Fan
CENTRIFUGAL FAN
Used a rotating impeller to move the air stream.
Airflow changes direction twice - once when entering
and second when leaving .
Rotating impeller increases air velocity.
Air speed is converted to pressure.
This fans produces High Pressure which ranges from 550
mmwc to 1400 mmwc.
Efficiency varies from 60-83 %.
Used for Dirty air stream condition and material
handling application.
APPLICATIONS:
Radial
Forward curved
Backward inclined
1.Radial Blade Fan
Characteristics:
A fan with flat blades
Usually contain 6 to 16 impeller blades.
High static pressures up to 1400 mm WC
Low/medium airflow rates only.
Efficiency ranges from 69% - 75%.
Simple in Design.
Have large running clearance
Applications:
Characteristics:
Have forward-curved blades.
Usually contain 24 to 64 impeller blades.
Produces low pressure up to 5 in-wg
Efficiency ranges from 60% - 65%.
Lighter in construction and less expensive
Provide a low noise level and relatively small air
flow with a high increase in static pressure.
Applications:
Applications:
Handles large volume hot dust/ash laden flue gases which are exhaust
from furnace.
High power requirement than FD fan ,it require 1100 KW motor for
200MW plant .
Visual inspection
Alignment check
Checks of belts and couplings
Measurement of axial clearances
Disassembly plus visual inspection of parts
Dimensional measurements
EXECUTION OF WORKS
Cleaning & steaming
Sandblasting
Preparation of technical drawings for machining by
in-house engineering team
Machining of parts (bearing housings, rotors, )
Balancing of rotating parts
Coating of rotating parts
Assembly
Coating of exterior
Alignment (in case of motor-fan combination)
BLOWERS
Blowers can achieve much higher
pressures than fans, as high as 1.20
Kg/cm2.
The impeller is typically gear-driven and
rotates as fast as 15,000 rpm.
They are also used to produce negative
pressures for industrial vacuum systems.
TYPES OF BLOWERS
Centrifugal blower
Positive displacement
CENTRIFUGAL BLOWERS
Typically operate against pressures of 0.35
to 0.70 Kg/cm2.
They are most often used in applications
that are not prone to clogging .
Gear-driven impeller that accelerates air
Single and multi-stage blowers
Airflow drops if system pressure rises
POSITIVE DISPLACEMENT BLOWERS