Centrifugal Fans

OVERVIEW

Industrial Centrifugal Fans differ from Industrial Axial Flow Fans in the way they move the air. A Centrifugal Fan (or Centrifugal Blower) typically has one of seven types of wheels that draws the air into the inlet of the blower housing, through the wheel, and discharges it at 90 degrees out through the discharge of the housing. An Axial Flow Fan or Industrial Axial Fan uses a propeller to draw the air into it and discharges it in the same axial direction. An "air moving device" with a propeller is typically referred to as a Fan, while one with a wheel is typically referred to as a Blower.

In this section we will cover industrial Centrifugal Fans, referred to as blowers. For information about axial type fans, see Industrial Axial Fans or Industrial Axial Flow Fans.

Making the proper centrifugal fan selection, involves considering the following conditions the blower will be subjected to:

1. What is the airflow that will be required?
Airflow is rated in cubic feet of air per minute (CFM) or in metric equivalent, it is rated in cubic meters per hour (M³/Hr).

2. What is the static pressure through the complete system?
This is rated in static pressure water gauge (SPWG) or in metric equivalent, it is rated in Pascal’s (Pa). SPWG or Pa is the resistance to flow, or friction, caused by the air moving through a pipe or duct. Be sure to include losses through filters, dampers, etc.
NOTE: If the static pressure on the inlet side of the blower will exceed 15” SPWG, a
rarefication and a suction pressure correction chart, see pages 6 and 7 of our Model HP-Series II catalog.

3. What is the ambient air temperature outside the blower?

4. What will be the airflow conditions through the blower?

1. Clean or dirty (contaminated) air?
2. Dry or wet (moisture laden) air?
3. Temperature of air?

5. What is the altitude the blower will be operating at?

6. Is anything going through the blower that could be explosive or flammable?

7. Will the general location the blower will be operating in contain any type of explosive or flammable material or liquid?

8. If the blower will be used to convey material, answer the following:

1. What is the material?
2. How much does the material weigh, in pounds per cubic foot?
3. How many pounds will you need to convey per hour?
4. Is the material long and stringy or granular?

Most Centrifugal Fans (Blowers) can be used for any of the above parameters except, if conveying material, a blower with a forward curve (squirrel cage) wheel is not suitable. The best centrifugal wheel type for conveying material is a radial wheel or an open radial wheel. If the material you will be conveying is log and stringy, like paper trim or fibers, only an open radial wheel should be used. The best models to use, for conveying material through the fan, are Models PB, SPB or PBS Pressure Blowers and Model RBE Radial Blade Exhauster. Models HDBI (Heavy Duty Backward Inclined Blowers) and HDAF (Heavy Duty Airfoil Blowers) are also used in many dust collector applications where the blower is on the clean side of the dust collector.

If the blower will be used to create suction, pressurization, cooling, combustion air, forced ventilation or general ventilation, then only the first seven conditions above need to be considered. After the first seven conditions are known, the blower selection will be based on the type of blower that is best suited by performance, design and features that best meet those conditions.

Cincinnati Fan does not manufacture any consumer or residential type centrifugal fans. But, we do manufacture 14 models of Centrifugal Fans (Blowers) that are designed and constructed as industrial type. We manufacture centrifugal blowers in the ¼ to 125 horsepower range, with airflow capacities from 50 to 51,900 CFM and static pressures from 1/8” to 78” SPWG.

APPLICATIONS

While a list of all the applications our Centrifugal Fans are used for would be extremely long, the most common include:

• Conveying material in dust collector systems or loading to silos, trucks and railroad cars.
• Combustion air for burners and industrial water heaters.
• Cooling electrical equipment or parts from heat curing ovens and kilns.
• Pressurizing cabinets, vaults or rooms.
• Blow-off systems to remove moisture from parts prior to painting, coating or packing.
• General ventilation of rooms or factories.
• Providing suction or pressure for industrial process air flotation tables.
• Drying ink on cans and bottles, silk screen and printing processes.
• Food processing.
• Circulating air in ovens and dryers to eliminate cold spots.
• Forced ventilation of AC and DC motors, traction motors and electrical cabinets.

BENEFITS

The benefits of Cincinnati Fan Centrifugal Fans are:

• Most all types and models, with most accessories, are shipped within 10-15 working days. Some models available on a 5 Day RUSH program, with most accessories. Quicker than industry standards.
• Spark resistant, cast aluminum wheels are standard in our PB and SPB Models. Ideal for applications requiring spark resistant construction with quick deliveries.
• All fabricated steel models have continuously welded housings for additional strength. Superior strength over stitch welding or lock seams.
• Heavy duty, industrial components and continuous duty motors ensures long lasting operation minimizing equipment down time. Dependable service with few field problems.
• All aluminum or all stainless steel fan construction is “not special” for us. We manufacture most models with both types of construction almost weekly. Faster delivery to you.
• All of our Industrial Blowers are available with multiple wheel sizes and some are also available with multiple housing widths from 50% to 100%, in 5% increments. Direct driven fans can be selected instead of larger, heavier, more expensive belt driven fans. Less expensive, more compact and lighter weight. Design flexibility.
• Belt driven models utilize wider spacing between the fan bearings which increases the bearing life. Less down time before replacement bearings are needed.
• All fans and blowers are manufactured in our 110, 000 square foot, state-of-the-art factory in Mason, Ohio. Not imported.
• Service! Without it, all the above is meaningless. We pride ourselves and are highly respected in the fan industry for the quality and service we give all our customers. Let us prove it to you also.

The design steps, listed previously, are critical for the proper selection and construction of your centrifugal fan. We have over 170 experienced sales engineers across the U.S.A. and Canada ready to assist you in making the proper fan or blower selection. Call our sales office for your area. They most likely have already sold some blowers for your type of application.

We are " The OEM and Industrial Air Handling Specialists" Let us prove it to you.