Industrial blowers are used to facilitate air flow for ventilators, production processes, and transportation of materials. Air blowers, industrial blowers, blower fans and industrial fans are all words that describe the same equipment. They use an impeller or propeller to "inhale" or "exhale" the air, providing ventilation, suction, and exhaust. They may be portable or stationary. Industrial fans and blowers come in a wide range of sizes and capacities, from hand held models, such as heat guns, to the world's largest snow blower, with a 1,360 horsepower centrifugal blower that can move up to twelve thousand tons of snow per hour. Blowers have been used to operate player pianos and pipe organs. They are used to make snow on ski slopes, blast sand, and move foodstuff in every phase of processing, from field to grocery store shelf.
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The History of Industrial Blowers
Georg Pawer made mention of centrifugal vent fans being used in mining as early as 1559, but the first notable use of an industrial fan came in 1827 when Edwin A. Stevens developed a fan to blow air into steamship boilers.
The first patented centrifugal fan was invented in 1832 by Lieutenant General Alexander Sablukov of the Imperial Russian Army.
The first actual industrial blower was developed between 1854 and 1859 in Connersville, Indiana, when workers were trying to speed up the drying process for a wooden water wheel that had swelled up and stopped rotating. Once the hub dried out enough to turn, the workers began to turn the wheel.
Philander and Francis Roots took notice of the airflow created by the spinning wheel and began to visualize the rotary positive displacement blower. The first positive displacement pump was marketed in 1859 by the Roots Blower Company. The Roots type of blower is still manufactured worldwide.
In 1862, Theophile Guibal patented a centrifugal blower that incorporated a spiral casing around the fan blades and a flexible shutter, which allowed control over the velocity of air exiting the exhaust portal. Far superior to open fan systems, these blowers were used extensively for ventilating mining operations.
Found on every vessel in the U.S. Navy since 1945, the Red Devil is an explosion proof portable blower that provides ventilation during shipboard emergencies. Known for its simplicity and reliability, this vane axial fan meets very strict Mil-specs regarding use of a blower in the vicinity of flammable materials and ignitable gases.
Design of Industrial Blower Systems
Blowers specs are listed by their flow and pressure rates. The ratio of inlet pressure to outlet pressure will determine which fan or blower should be chosen for a specific task. Flow rate, required pressures, and frictional losses from piping or ductwork are calculated when designing the system.
Performance curves and charts, typically available from the manufacturer, can aid in determining which type and size best suits the purpose. Most of the blower capacity charts are based on a 70 degree F temperature, at sea level. Adjustments can be made to accommodate for temperature and elevation changes.
- Blower Motors
- The type of blower motor will be determined by the substance being moved, how large the scope of the movement, and how quickly it needs to move there. Belt driven blowers are connected to the power source by v belts on a system of sheaves and pulleys. This allows some control over speed but also causes loss of power transmission. Direct drive blowers are air blowers whose blade systems are directly connected to a motor instead of to a series of gears. They are connected directly to the power source so there is minimal power loss. Speed control is determined by the speed of the motor.
- There are ten basic mounting configurations for belt driven or direct drive blower systems, including top, bottom, or side mounts, and close mounted or coupled options.
- Blades of the Fan or Blower
- The blades of the fan or blower come in a variety of configurations that are designed for use with specific materials. Fans and impellers may be oriented to travel clockwise (CW) or counterclockwise (CCW). Backward inclined blades, forward curved blades, and radial (paddlewheel) blades each offer a different level of air movement capability, forward curves move more air than backward inclined blades, but with less pressure. Radial blades simply push the air straight through the system, but may be made of self cleaning materials for use in moving dirty products. Paddlewheel fans are common in pneumatic conveyor systems, especially for foodservice and pharmaceutical purposes.
- Other Design Elements
- Flow capacity, operating pressure, port design, and control design are factors to consider when choosing a blower. Capacity is typically rated as cubic feet per minute (CFM). Operating pressures are measured as inches of water or Static Pressure Water Gauge (SPWG).
- Port design will determine how inlet and outlet ports are attached to the ductwork or piping system. They may be round or rectangular, flanged or threaded. Special features of the system may include control over speed or volume through the use of dampers, louvers, diffusers, or variable speed operation.
- Maintenance of the system is paramount to its continued usefulness and longevity. Some things to look for when designing or purchasing a blower should include sealed exterior seams, access doors that have seals or gaskets, lubrication access points, and split housings for access to wheel and shaft for cleaning and lubrication.
Where Blowers are Used
- Using a Blower in a Residential Setting
- Blowers and fans are used in every context in which people working indoors require access to clean air at comfortable temperatures. Because these conditions need to be met in every workplace, every commercial and industrial setting requires a means by which air can be circulated and treated. For this reason, exhaust and ventilation fan systems account for much of the demand for industrial blowers. Every modern commercial building and most residential homes utilize blowers of some sort to move air for the comfort, health, and safety of the occupants. The Air Movement Control Association (AMCA) was established to make sure those objectives are met. The Heating, Air Conditioning, and Ventilation (HVAC) industry provides the components and services.
- HVAC blowers are found in automobiles, stores, restaurants, medical facilities, theaters, stadiums, underground train systems, and mining operations. They may be used to provide fresh air or to remove noxious odors created by certain operations, such as those utilizing particular plants, foods, minerals, or chemicals.
- Using a Blower in an Industrial Setting
- Glass and plastic manufacturers rely on industrial blowers to form bottles and jars and to facilitate production of items made by injection molding processes. Industrial blowers are used to cool products, such as glass and metal, after processing. They are used to dry grain, paper, and raw materials. Industrial kitchens, ovens, or kilns rely on them to maintain correct temperatures and to disperse excess heat or toxic gases.
- Dust, fumes, and smoke created in other manufacturing processes are removed through the use of blowers called "scrubbers". These may be wet or dry. Wet scrubbers introduce a stream of water or cleaning fluid into the airstream. This process washes the hazardous gases or dangerous particulates from the air before it is exhausted. A dry scrubber induces an alkaline slurry to clean acidic gases before releasing the air. Both types must be made from or treated with corrosion resistant materials.
- 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.
Varieties of Industrial Blower
- Axial Blowers
- Use a simple propeller revolving around a central axis to create a parallel air flow. The units may be belt drive or direct drive and are used to move massive quantities of air, such as is needed for air conditioning of large buildings or industrial drying. The air pressure is increased through the utilization of a fan wheel and travels in a lateral direction, offering high volume of movement at low pressures.
- Vaneaxial Blowers
- Utilize a disk type of propeller to create air flow. The impellers come in a variety of styles suited for the type of service they will provide. The vane structures may be backward curved, backward inclined, open radial, closed radial, tipped radial, or paddle wheel styles. The wheel may be shrouded or unshrouded.
- Radial Fans
- Radial/Centrifugal 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 water wheel 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. 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. Centrifugal blowers may be single or multi-stage.
- Positive Displacement Blowers
- Also known as rotary lobe blowers, use two counter-rotating lobes to create flow. They are used to move fluids and gases and to facilitate pneumatic conveyors. A positive displacement blower is a better option than a centrifugal blower for moving fluids, such as fountains, ponds, or sewage, or large volumes of air under high pressure, such as ventilation in hospitals, shopping malls, high rise apartments, and underground parking garages. They are found in sewage aeration ponds, petrochemical plants, and at the local bank.
- Regenerative Blowers
- Resemble centrifugal blowers, in that they use an impeller on a shaft to induce air and create a focused output of linear flow. The inlet and outlet ports are mounted perpendicular to the impeller. Centrifugal force pushes the air or fluid outward as a follow-on impeller vane compresses it into a spiral path under constant acceleration. This creates the regenerative effect. This type of blower system is used where viscosity, distance, complex ducting configurations, or other less than optimal material travel circumstances occur.
- Explosion Proof Blowers
- Used extensively throughout the military, industrial facilities, and manufacturing plants where combustion is a concern due to proximity of volatile materials. These units are used to ventilate fueling stations, grain silos, paint booths, refineries, ammunition factories, chemical manufacturing and storage facilities, and mines.
- There are three basic types of Explosion proof blower that must meet standards set by the National Fire Protection Association (NFPA) and Air Movement Control Association (AMCA).
- Type A uses nonferrous, spark resistant materials, including brass, aluminum, Monel, Inconel, fiberglass, or plastic, for all components of the unit that come in contact with the airflow it produces. They are used where explosive gases and powders are or may be present.
- Type B blowers are made with a nonferrous fan, usually aluminum, and require a rubber grommet, or rubbing plate, be installed in the shaft hole, where it enters the motor housing. They are primarily found in facilities where flammable liquids are made, packaged, and stored.
- Type C blowers are made so that any ferrous parts will not strike each other during operational shifts. These are used in places where sparks may cause ignition of dry materials, such as grain or dust. Some stainless steel alloys are spark resistant and may be used in the manufacture of Type B and C blowers.
- 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
- Air blowers that are used to displace gasses from one area to another. While the word “exhaust” is usually associated with gasses produced by industrial processes, all fans that remove a gas from one area and direct it into another are exhaust fans. They are key components of ventilation systems and are usually the last stop in ductwork before the expulsion of air from indoor areas to outdoor areas.
- Gas Blowers
- 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
- Air blowers that are designed for use in applications where a high-pressure airflow is needed for something. Artificially high or low pressure air flows are used in all kinds of industrial, commercial and residential contexts.
- Power Blowers
- Used in greenhouse and lawn and garden applications, involving movement of air over a large area or heavy-duty air movement.
- 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.
- 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.
- Vacuum Blowers
- 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.
Things to Consider When Purchasing
- Choosing the Right Blower
- Almost every application for industrial blowers is unique. The industrial blower manufacturer will be able to help select the right blower, fan or impeller, motor, controls, and ducting material for each specific need. Finite Element Analysis (FEA) and Computational Fluid Dynamics (CFD) programs will calculate the specifications for each application. 2D CAD designs, 3D models, and BIM programs can be provided to ensure the proper functionality of the system.
- If industrial standards regarding health and safety are in question, the designer or manufacturer will be able to provide appropriate equipment and materials to meet those requirements.
- Find the Right Industrial Blower Company
- The fan manufacturer should have strict quality control standards from the time raw materials are received, through fabrication, finishing, and final assembly of the product. Vibration and balance analysis should be performed on the propellers, impellers, and wheels. The manufacturing company and seller should be able to offer operational advice, maintenance information, and always back their product after the sale.
- 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.
- 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.
- 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.
- 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.
- The point on an industrial fans wheels from which the fan blades extend.
- 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.
- 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.
- 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.