Blowers

Competition for customers in the blower market has led to the development of specialized blower systems, like regenerative blowers, which have been developed to improve the efficiency of HVAC systems and for use in other special settings. Direct drive blowers were developed to provide for the generation of precise, predictable air flow. Outside of air quality control applications, blowers are used for few other purposes. High velocity fans, which are sometimes also known as high-pressure blowers, are often used to dry things. Following surface treatment processes, certain varieties of metals or plastic may be subject to drying with an industrial blower to speed up a drying process or to impart certain properties on the surface. Blowers are also used to dry carpet and other surfaces after cleaning or spills. The two main varieties of blowers are axial blowers and centrifugal blowers.

Every industry makes use of blowers. However, despite their wide use in industry, the number of applications for air blowers is limited to ventilation, drying and a few other uses. Regenerative blowers can be used to aerate ponds, spa pools and other small bodies of water. Centrifugal blowers can be used to create vacuums for surface treatment processes and in lab environments. Very large blowers can be used in wind tunnels during aerodynamics research and development. Other large blowers can be used to spread snow on ski slopes. Blower use outside of the contexts of heating, cooling or ventilation is usually specialized, and this reality has nourished the creativity of designers, engineers and manufacturers who produce new innovations in blower technology. Within the context of producing ventilation equipment in special settings, developments like the direct drive blower have allowed for steady and predictable airflow into sensitive areas like clean rooms, laboratories and environmentally sensitive hospital wings like burn units. That said, since the development of the original concept of blowers, only two main configurations of industrial blowers have been developed.

The first variety of blowers is the axial blower configuration. Axial blowers feature several curved blades that spin around an axis. The movement of axial blower blades can be compared to the movement of hands around a clock face. When the curved blades spin around in a circle, they create an imbalance of pressure in the air around them. This imbalance of air pressure causes airflow, and as long as the blades continue to spin, the imbalance continues as well. This creates continuous airflow. Examples of axial fans are ceiling fans, free-standing and mounted oscillating fans, portable desk or table fans and some varieties of ventilation exhaust fans. Radial (or centrifugal) configurations make up the rest of industrial blower design. Radial fans create airflow in the same way that axial fans do (by creating an imbalance in air pressure), but the mechanism by which they create the imbalance of air pressure is quite different. A radial fan's blades spin around in a way that more resembles the forward turning of waterwheel paddles than the movement of hands on a clock. Another difference is that radial fan blades spin within an enclosure (which is called an annular housing). As the blades turn, they suck air into the annular housing. The air in the housing becomes pressurized by the blades because of centrifugal motion. It is then expelled through a chute.

Both axial and radial blowers have their place in the various contexts in which industrial blowers are used. Radial blowers, when operating at the same RPM as axial blowers, can produce a higher-pressure flow of air because of the added efficiency that centrifugal motion allows their pressurization process. In some cases, though, a narrow, high-pressure stream of air is not appropriate. In warehouses without air conditioning, for example, when employees need relief from heat during the summer, the airflow from a large axial fan will distribute itself more appropriately than will a radial fan. In complicated ductwork, on the other hand, sharp turns may make axial fans impractical for airflow generation. Radial fans suck air into their enclosures from the side, which makes them perfect for directing air through sharp angles in ductwork.  There are also some cases in which both axial and radial fans are impractical or impossible to use, even though some kind of fan cooling system is necessary. In these cases, which usually involve machines that already have a motor, a fan can be connected to an existing motor and draw its power from that source. One such example is in automobiles, in which fans are connected to existing moving parts instead of to their own, independent motor.

Image Provided by Tuthill Vacuum and Blower Systems

Image Provided by the National Turbine Corporation

Blower Types

• Air blowers blow or pump air through openings in a system. Applications include pools, Jacuzzis, and spas, fish tanks and aquaculture applications.
• Axial fans are air blowers whose blades spin around an axis to create air flow.
• Axial flow fans are used for ventilation purposes. In axial flow fans, air maintains parallel movement within the fan, and maintains linear movement during emergence from the fan.
• Blower Fans are industrial blowers that also use a metal fan for cooling and drying applications.
• Centrifugal blowers and fans are more useful in air pollution control than axial flow fans are. In centrifugal blowers, air maintains perpendicular movement in relation to the fan shaft while in the fan system, and emerges rotationally from the fan outlet.
  
• Corrosive duty fans are specially designed for use in corrosive environments or any application that involves chemical or gas movement. Fiberglass is often used in this type of construction.
  
• Crossflow blowers, or tangential blowers, release air after two cycles of circulation within the blower. Crossflow blowers are found in applications involving large areas requiring low pressure and high levels of airflow.
• Direct drive blowers are air blowers whose blade systems are directly connected to a motor instead of to a series of gears.
• Displacement blowers are used in applications that transfer large amounts of air for use in compression situations such as in the automobile industry.
  
• Electric blowers require an electric motor for operation. Electric blowers cover a number of products, ranging from hair dryers used in beauty salons to leaf and lawn blowers.
  
• Exhaust fans are ventilation systems used to reduce or eliminate odors, smoke, moisture or stale air from an area by removing the offensive air and replacing it with fresh air. Exhaust fans are common in kitchens, restaurants and bathrooms.
  
• Gas blowers are used to control gas flow and gas pressure. Gas blowers process methane, natural gas and other gases in gas well and chemical applications.
• High pressure blowers are air blowers that create a high-pressure air flow.
• High velocity fans provide high levels of air movement.
• Industrial blowers are air blowers intended for use in industrial settings.
• Industrial fans are made from different materials than residential or consumer fans and are used in industrial settings.
• Low pressure blowers are used in applications where oil free air and almost silent operation are desired. These blowers tend to be small and use a small amount of energy to function.
  
• Power blowers are used in greenhouse and lawn and garden applications, involving movement of air over a large area or heavy-duty air movement.
  
• Regenerative blowers are used in the paper, photography and recreational industries for applications including ink and film drying and pool and spa aeration. During operation, air enters the blower and moves centrifugally out of the blower through the rotational force of the blower blades; however, during this process of rotation some of the air drops past the blade and moves through the cycle again, which is why the blower is known as a regenerative blower.
  
• Turbine blowers generically refer to any type of blower that is built in a turbine style, consisting of rotating blades, which create the air flow that is then blown.
  
• Vacuum blowers are called such because they essentially derive their blowing power via a vacuum which can either inhale or exhale a vast amount of air. When vacuum blowers exhale, they technically are not vacuums.
• Ventilation fans are air blowers used for the creation of air flow through ventilation systems.

Blower Terms

Air Changes - The amount of time, expressed in minutes, that is takes for industrial blower systems to replace air in an area.

Air Distribution - The delivery of outdoor or conditioned air via industrial blowers to various spaces in a building, usually by mechanical means.

Air Velocity - The rate and direction of air movement produced by industrial blowers.

CFM - Abbreviation for cubic feet per minute; a measurement of the amount of air industrial fans and industrial blowers move through ventilation and circulation during operation.

Circulation - The process used by industrial blowers and industrial fans for moving air around within a specific area.
 
Cross Ventilation - Air that enters on one side of a room and leaves on a different side of the same room as it is blown by industrial blowers or industrial fans.
 
Damper - The mechanism responsible for the regulation of airflow by industrial fans or industrial blowers systems; dampers consist of inlet dampers, which regulate airflow into industrial blowers or industrial fans systems, and outlet dampers, which control air movement out of industrial blowers or industrial fans systems.
 
Fan Blade - The fan component extending from the hub of industrial blowers or industrial fans that rotates, cutting into the air and producing air movement. Fan blades may stick straight out in a radial position, curve forward in the direction of fan wheel rotation or curve backward.
 
Fan Drive - The fan mechanism responsible for controlling the movement of the fan wheel on industrial blowers or industrial fans, including fan wheel speed.
 
Fan Wheel - Fan component consisting of a hub and blades, which rotate about the wheel in order to produce air movement of industrial fans or industrial blowers.
 
Hub - The point on an industrial fans wheels from which the fan blades extend.
 
Multizone - A building or part of a building that comprises a number of zones or cells.
 
Static Pressure - The amount of resistance in a circulation or ventilation system that industrial fans or industrial blowers must surmount to ensure proper air movement.
 
Total Pressure - The total amount of pressure, measured in Pascals, that industrial fans or industrial blowers produce, including both the static pressure and the velocity pressure.
 
Velocity - The rapidity of air movement in a ventilation system produced by industrial blowers or industrial fans, measured in feet per minute (fpm).
 
Velocity Pressure - The amount of pressure in a circulation or ventilation system resulting from air movement from industrial blowers or industrial fans.
 
Ventilation - A process of industrial fans and industrial blowers in which air is moved into, out of and between different areas. Ventilation is used to replace old, stale, odiferous or contaminated air with fresher, cleaner air.