Standard or custom, we build every backward-inclined centrifugal fan as if we were building it to use ourselves.
A backward-inclined fan, or backward-inclined blower, is used for clean-air applications to move high volumes of air at different static pressures, such as in dust-collection systems. At AirPro, our engineers have decades of combined experience in the industry, giving us the ability to design and manufacture a wide range of fans to meet or fit many needs and applications. The AirPro backward-inclined fan is offered in belt-driven, direct-driven, and direct-coupled arrangements along with various impeller and housing widths.
As a highly efficient model, the AirPro backward-inclined fan offers lower sound levels and energy costs than many other fan types. The fan impeller has been designed with a focus on high operating efficiency without compromising high mechanical strength in its specific blade angles and various streamlined profiles. Whether standard or custom, each AirPro backward-inclined centrifugal fan is designed and built with unmatched quality and backed by responsive, respectable service.
Will the AirPro backward-inclined fan work for my application?
Whether you are considering a standard engineered backward-inclined blower or one that is custom built to your specifications, you need to be confident it will work for your application. We want you to be sure. Use our online selection tool, myAirPro, to specify and price a backward-inclined fan, or talk to one of our engineers at 715-365-FANS (3267) or contact us.
Accessories and Spare Parts
When you specify or purchase a backward-inclined centrifugal fan from AirPro, be sure to consider accessories and spare parts, too. Accessories such as dampers give you greater flexibility to manage the flow of air into and through the fan. And, it is always a good idea to have spare parts on hand for each backward-inclined blower to help keep your operation up and running.
Backward-Inclined Fan Performance & Design
Based on performance testing according to AMCA standards, Finite Element Analysis, and years of engineering and field experience, AirPro’s backward-inclined fan has been developed with the following performance and design characteristics:
- Air volumes up to 350,000cfm (higher volumes available with custom design)
- Static pressures up to 25”wg (higher pressures available with custom design)
- Temperatures up to 1000°F
- High static efficiency up to 78%
- Non-overloading power curve
- Single Width, Single Inlet (SWSI) and Double Width, Double Inlet (DWDI)
Clean-air applications that use the AirPro backward-inclined fan include:
- Dust-collection systems
- Pneumatic conveying equipment
- Pollution-control equipment
- Heat exchangers
- Rotary drum dryers
- Gas- and odor-control equipment
- Bulk material handling systems
Fan arrangements define the way a fan is driven by a motor, how the motor mounts to the fan, and are based on AMCA standards. The backward-inclined fan is available in the following arrangements:
- Belt-drive– The fan shaft is driven by the motor shaft through sheaves/pulleys and v-belts. Belt-driven fans provide speed and flexibility, as they enable the fan operating speed to differ from the motor synchronous speed. There are power transmission losses associated with belt-driven fans that should be considered when selecting the motor horsepower.
- Arrangement 1 – The fan and motor are separately mounted to a unitary base. OSHA guards are required.
- Arrangement 9 – The motor mounts to the side of the fan pedestal with no unitary base required. OSHA guards are required.
- Direct-Drive– The fan operates at the synchronous speed of the motor, as the fan is driven directly either with the fan wheel mounted on the motor shaft or with the fan shaft directly -coupled to the motor shaft. Direct-driven fans experience negligible power transmission losses.
- Arrangement 4 – This is a low cost arrangement, as the wheel is mounted directly on the motor shaft and does not require bearings, belts, OSHA guards, or a unitary base. This arrangement is not available for every fan, as operating temperature, wheel size, materials, and other criteria can be limiting factors.
- Arrangement 4V / Top Mount – The wheel is also mounted to the motor shaft, but in a vertical position. This fan is typically mounted on the top of a dust collector with the fan inlet in a vertical position and the fan discharging horizontally.
- Arrangement 8 – The fan shaft is directly coupled to the motor shaft with a flexible coupling. This arrangement offers fewer potential maintenance issues than other arrangements, as there is no belt pull on the bearings, and the motor experiences neither belt pull nor the weight of the wheel on its shaft. OSHA guards are required, and a unitary base may be required.
- Other Arrangements
- Arrangements 3 and 7 – These can be either belt or direct drive, and both arrangements involve a bearing on either side of the fan wheel. The bearing is supported either by separate pedestals or by a support structure integrated with the fan housing.
- Plug – This is used when the fan will mount to an enclosure, such as an oven, with the wheel extending into the enclosure and is often used for circulation of high air volumes at low static pressures.
- Square – In direct drive, the fan wheel mounts directly to the motor shaft. The fan housing is supported by a square structure on either side of the housing. This arrangement is often used in applications with limited space and tight footprints.
Materials of Construction
We offer a wide range of materials to construct the fan wheel, airstream parts or the entire fan. Whether your application involves high operating temperatures, caustic contaminants, or explosive environments, AirPro has the appropriate materials, including:
- All carbon steel grades
- All stainless steels
- Nickel-based alloys (625, C22, C276, etc.)
Backward-Inclined Fan Finishes
We offer various finishes and linings to accommodate multiple application requirements. Our standard industrial primer and enamel will protect our fans in a general industrial environment. We also provide finishes and linings that offer protection in specialized environments, such as high temperature, corrosive, abrasive, and food-grade environments.
- Industrial enamel
- Wet paints, including:
- Powder -coating
- Special linings, including:
- Ceramic tile
- Other custom coatings available
Routine maintenance is essential to the successful, long-term operation of your backward-inclined fan. We understand that this can be a challenge due to space limitations and fan accessibility. AirPro fans have several features available that are designed to facilitate routine maintenance, including:
- Flush-mounted and gasketed access door into the fan housing
- Split-housings for wheel and shaft removal
- Extended lubrication lines for motor and bearing ports
- Lubrication access holes in the shaft guard
- Tachometer access hole in the belt guard
- Sealed exterior seams for rust prevention
Quality Control Inspection
Inspections are conducted to ensure AirPro Fans not only comply with the customer’s requirements, but that they also maintain AirPro’s high standard of quality. These inspections are conducted throughout the manufacturing process, including:
- Material receiving and preparation
- Fabrication and welding
- Paint/coating and surface preparation
- Product final assembly
- Balance and vibration analysis
- Final inspection before shipping with QC documentation provided
Fan Balance and Testing
Wheel balance and fan vibration levels are issues we take very seriously; ignoring them can cause catastrophic failures in the field. We conduct various tests to address these critical issues.
- Wheel is dynamically balanced to ISO G6.3 minimum
- Full-speed, mechanical run test is performed on the fan assembly
- Vibration analysis conducted at fan’s operating speed
- Vibration analysis conducted during fan coast-down to detect any resonance
- In-depth bearing analysis designed to detect any potential bearing problems