Blowers can achieve much higher pressures than fans, as high as 1.20 kg/cm2. They are also
used to produce negative pressures for industrial vacuum systems. Major types are: centrifugal
blower and positive-displacement blower. Centrifugal blowers look more like centrifugal pumps than fans. The impeller is typicallygear-driven and rotates as fast as 15,000 rpm. In
multi-stage blowers, air is accelerated as it passes through each impeller. In single-stage blower, air does not take many turns, and hence it is more efficient. Centrifugal blowers typically operate against pressures of 0.35 to 0.70 kg/cm2, but can achieve higher pressures. Oincreases, which can be a disadvantage in material conveying systems that depend on a steady air volume. Because of this, they are most often used in applications that are not prone to clogging. Positive-displacement blowers have rotors, which "trap" air and push it through housing. Positive-displacement blowers provide a constant volume of air even if the system pressure varies. They are especially suitable for applications prone to clogging, since they can produce enough pressure - typically up to 1.25 kg/cm2 - to blow clogged materials free. They turn much slower thancentrifugal blowers (e.g. 3,600 rpm), and are often belt driven to facilitate speed changes. 5.3ne characteristic is that airflow tends to drop drastically as system pressure
Centrifugal Fans
Type Characteristics Typical Applications
Forward- Medium pressure, Low pressure
curved high flow, dip in HVAC,
blades pressure curve, packaged
efficiency higher units, suitable
than radial fans, for clean and
power rises dust laden air /
continuously gases
Backward High pressure, HVAC,
curved high flow, high various
blades efficiency, power industrial
reduces as flow applications
increases beyond forced draft
point of highest fans, etc.
efficiency
Airfoil Same as backward Same as
type curved type, backward
highest efficiency curved, but for
clean air
applications
Axial-flow Fans
Type Characteristics Typical Applications
Propeller Low pressure, high Air-circulation,
flow,low efficiency, ventilation,
peak efficiency \ exhaust
close to point of free air
delivery (zero static
pressure)
Tube-axial Medium pressure, HVAC, drying
high flow, higher ovens, exhaust
efficiency than system
propeller type, dip in
pressure-flow curve
before peak pressure
point
Vane-axial High pressure, High pressure
medium flow, dip applications
in pressure-flow including
curve, use of guide HVAC
vanes improves systems,
. efficiencyexhausts
used to produce negative pressures for industrial vacuum systems. Major types are: centrifugal
blower and positive-displacement blower. Centrifugal blowers look more like centrifugal pumps than fans. The impeller is typicallygear-driven and rotates as fast as 15,000 rpm. In
multi-stage blowers, air is accelerated as it passes through each impeller. In single-stage blower, air does not take many turns, and hence it is more efficient. Centrifugal blowers typically operate against pressures of 0.35 to 0.70 kg/cm2, but can achieve higher pressures. Oincreases, which can be a disadvantage in material conveying systems that depend on a steady air volume. Because of this, they are most often used in applications that are not prone to clogging. Positive-displacement blowers have rotors, which "trap" air and push it through housing. Positive-displacement blowers provide a constant volume of air even if the system pressure varies. They are especially suitable for applications prone to clogging, since they can produce enough pressure - typically up to 1.25 kg/cm2 - to blow clogged materials free. They turn much slower thancentrifugal blowers (e.g. 3,600 rpm), and are often belt driven to facilitate speed changes. 5.3ne characteristic is that airflow tends to drop drastically as system pressure
Centrifugal Fans
Type Characteristics Typical Applications
Radial High pressure, Various
medium flow, industrial
efficiency close to applications,
tube-axial fans, suitable for air
power increase dust laden,
continuously moist
air/gases
curved high flow, dip in HVAC,
blades pressure curve, packaged
efficiency higher units, suitable
than radial fans, for clean and
power rises dust laden air /
continuously gases
Backward High pressure, HVAC,
curved high flow, high various
blades efficiency, power industrial
reduces as flow applications
increases beyond forced draft
point of highest fans, etc.
efficiency
Airfoil Same as backward Same as
type curved type, backward
highest efficiency curved, but for
clean air
applications
Axial-flow Fans
Type Characteristics Typical Applications
Propeller Low pressure, high Air-circulation,
flow,low efficiency, ventilation,
peak efficiency \ exhaust
close to point of free air
delivery (zero static
pressure)
Tube-axial Medium pressure, HVAC, drying
high flow, higher ovens, exhaust
efficiency than system
propeller type, dip in
pressure-flow curve
before peak pressure
point
Vane-axial High pressure, High pressure
medium flow, dip applications
in pressure-flow including
curve, use of guide HVAC
vanes improves systems,
. efficiencyexhausts
Great post. I’m trying for blogs on relevant topics but, very less resource
ReplyDeletewith blog commenting option. This material is quite a bit different in that the information is up to date.
Mechanical boosters
Tri lobe blowers