Blowers are used for smoke and contaminated air exhaust in industries
kitchen exhaust in commercial applications. Selection of suitable
depends on following factors:
of Plant / Kitchen facility.
of smoke generated.
hazard of smoke to the manpower / equipments inside the establishment.
layout and size.
are generally designed to delivery high volume of air at considerably
low static pressure (but still sufficient enough to overcome the
Blowers are used for cooling applications such as in Air Handling
Washer Unit, Cooling Systems and Machines in various industries.
Air volume for cooling
blower may vary from 300 CFM to 100,000 CFM.
Engineering of through the wall
exhaust fans, airflow exhaust ventilators, fume hood exhaust fans, roof
/ wall supply blowers, paint booth ventilation fans, high pressure air
blowers, air pressure blowers, high temperature air blowers, rotary air
blowers, air fan-blowers systems, roof blowers, roots blowers, oven /
dryer exhaust ventilators, heavy-duty ventilation fans, spray booth
exhaust fans, New York blowers, Dayton fans, Chicago blowers, American
Coolair ventilators, ACME ventilators, Twin City fans, Aerovent fans,
If ventilation system has not been properly maintained, clogged filters
or obstructed coils will reduce airflow. The greater the obstruction,
the greater the loss in airflow. Any leaks in the ductwork will
contribute to reduced performance, especially leaks around plenum
bulkheads that can lead to recirculation of air. Worn flexible
connectors are a common source of leaks and should be inspected
regularly. If the damper linkage is out of adjustment, the damper may
not be opening completely, thereby reducing performance. If inlet
dampers are used, make sure they are installed so that the air is
pre-spun in the same direction as wheel rotation. For all dampers, make
sure there is sufficient clearance for the blades to open and close
completely without hitting the ductwork or other system components.
Last, for systems with either pneumatic or electric controls, make sure
damper actuators are operating properly. Sharp changes in the direction
of airflow at either the fan inlet or outlet will disrupt the flow
through the fan and impair performance. If it is impossible to
straighten the ductwork entering and leaving the fan, the use of inlet
boxes and turning vanes can minimize performance losses.
Industrial processes and plant ventilation systems often need more air
than originally designed. Increased production requirements, process
changes, and facility renovations are a few of the major reasons.
Additionally, the lack of adequate maintenance over time can negatively
impact system airflows. This article discusses several procedures that
can increase airflow. Often airflow can be increased by adhering to
proper fan maintenance procedures as outlined in fan installation and
Fan speed can decrease by as much as 10% to 20% when belts are too
loose, with a corresponding loss of airflow. A fan cannot perform as
designed if the air flow surfaces are distorted by contaminants. Even
in large fans, a sixteenth of an inch of build up can reduce
performance. Centrifugal fans will move some air even when running
backwards. While some types would use so much horsepower they would
trip circuit breakers, other design s could run for years without being
detected. Fan components may be out of position due to routine cleaning
or painting or the wheel could have shifted during shipment. For
backward inclined fans, the relation of wheel to inlet cone is very
critical. Even a quarter of an inch can have a major impact. The fan’s
installation and maintenance literature shows the proper positioning of
the wheel to the inlet cone.
One of the easiest solutions to low airflow problems is speeding up the
fan. While airflow is increased by speeding up the fan, so too are
static pressure, noise, and power requirements. Therefore, while
increasing the fan’s speed is an easy procedure with low first cost,
the additional operating expense over time makes it the most costly
solution. When increasing fan speed, it is necessary to check the
maximum safe speed of the fan and make sure the motor is capable of the
horsepower required to run the fan at the new speed. But never run a
fan beyond its maximum safe speed.
On a first-cost basis, adding or replacing fan equipment is the most
costly alternative. However, on a life-cycle-cost basis, considering
operating and maintenance expense, it can be the least expensive, as
compared to increasing the speed of an existing fan. Sometimes a second
fan may be added, either in series or parallel with the original,
although it may be more cost effective to simply upgrade the system
with a new fan capable of the required airflow and pressure. Adding
another fan in series will increase the airflow because of the
additional pressure. The operating point of the new system moves
further out/up the system curve. Where duct size is adequate to handle
the desired amount of air but the existing fan doesn’t provide
sufficient pressure, a second fan in series may be the best solution.
However, make sure the ductwork can handle the increase in pressure.
Adding another fan in parallel with the first will increase airflow due
to the combined capacities. Because capacities are being combined
instead of pressures, a greater increase in airflow will result for a
given system. However, system pressures will also increase and caution
is required to avoid the unstable operating area of the combined fan
When more air is required it is important to investigate the system on
a step-by-step basis, considering the least expensive possibilities
first. For existing systems that seem to have lost performance, fan and
system maintenance is the place to start. Often, simply improving the
efficiency of existing components will suffice. For systems that
require greater airflow and / or pressure, increased fan speed is
generally the first alternative. However, when large increases in
performance are required, there may be no alternative but to purchase a