Backward Inclined Blowers
Backward inclined blowers, also known as backward curved centrifugal fans, move air efficiently using blades that angle away from the direction of rotation. This design helps reduce noise and allows the fan to handle higher air pressure without losing performance.
These blowers are commonly used in HVAC systems, industrial ventilation, and cleanroom environments where reliable airflow and energy savings are important.
Knape Associates distributes backward inclined blowers from several U.S.-based manufacturers, offering a wide range of models to meet different sizes, airflows, and application needs.
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Top Performance Features of Backward Curved Centrifugal Fans
Backward inclined blowers offer strong performance across various airflow and pressure requirements. They can handle higher static pressures than other fan types, making them suitable for systems with long duct runs or heavy filtration.Â
The blade design reduces turbulence, which lowers noise levels compared to forward-curved fans. When paired with EC (electronically commutated) motors, these blowers use significantly less energy by adjusting speed to match system demand.Â
Built for continuous use, they maintain reliable performance over long operating hours. Models are available in multiple configurations, including direct drive, belt drive, and high-efficiency airfoil blades.
Available Configurations for Backward Inclined Blowers Built for System Compatibility
Backward inclined blowers are available in multiple sizes, airflow capacities, and structural materials to fit diverse ventilation systems. Airflow ranges from 100 to 300,000 CFM, with static pressure capabilities between 0.2 and 40 inches w.g..Â
Housing and impeller materials include aluminum, steel, stainless steel, and composite options to support different environmental and performance needs. Models come in both direct drive and belt drive designs, with available features such as EC motors for energy efficiency, vibration isolation for noise control, and protective enclosures.Â
All units are manufactured in the United States to ensure consistent build quality and compliance with industry standards.
Manufactures we Represent
Industrial Blower Fan for Applications Across Key Industries
Backward inclined blowers support critical airflow needs in systems that demand high efficiency, stable pressure, and quiet operation.
These fans are engineered for performance in real-world environments where lesser designs, such as forward-curved or axial fans, often fall short due to pressure instability, noise, or limited durability.
The sections below outline how a backward inclined fan performs more reliably than common alternatives across different industries and applications.
HVAC Systems for Commercial Buildings and Data Centers
A backward inclined centrifugal fan maintains steady airflow even as system pressure changes, which is common in large HVAC systems. In commercial buildings and data centers, this fan type improves ventilation while keeping noise levels low.
Unlike forward-curved fans, which can become inefficient at higher pressures and speeds, an incline blower avoids performance drop-off and protects the motor from overload.
This makes it well-suited for variable air volume (VAV) systems, where demand and resistance often change throughout the day.
Industrial Ventilation for Dust Collection and Process Cooling
In industrial environments, a backward inclined blower is used in dust collection systems, high-pressure exhaust setups, and process cooling applications.
Its non-overloading power curve ensures the motor remains protected even if airflow resistance increases.
Forward-curved fans, often selected for their lower initial cost, can stall or overload under similar conditions, leading to more frequent maintenance and downtime.
A backward blower also handles more complex ductwork layouts without a loss in performance, giving engineers greater design flexibility.
Cleanrooms and Labs in Pharmaceutical and Electronics Manufacturing
Cleanroom applications require tight control over airflow and pressure to prevent airborne contamination. A backward inclined centrifugal blower delivers smooth, consistent airflow with less turbulence, which reduces particle movement in critical environments.
Axial fans, commonly used for general ventilation, cannot generate the static pressure needed to maintain laminar flow through HEPA filters.
The centrifugal ventilator preserves system stability while running quietly, which is essential in labs and clean manufacturing zones.
Food and Chemical Processing Facilities with Corrosive Environments
In food processing and chemical facilities, a backward inclined centrifugal fan is available in stainless steel or protective coatings that resist corrosion from cleaning agents, moisture, and chemical exposure.
These materials extend the fan’s service life and lower long-term maintenance needs. In comparison, forward-curved or plastic axial fans often fail early in these conditions, increasing the total cost of ownership.
The backward inclined fan also features self-cleaning blade geometry, which reduces buildup and helps maintain steady performance over time.
FRP Fans for Water Treatment and Harsh Environments
Fiberglass-reinforced plastic (FRP) backward inclined centrifugal blowers are a reliable option for water treatment plants and facilities with harsh chemical exposure.
These fans resist corrosion from constant contact with moisture, chlorine, and chemical vapors. While coated metal fans may deteriorate over time, FRP construction maintains structural integrity and airflow consistency in demanding environments.
A backward inclined centrifugal ventilator made from FRP also performs efficiently at the static pressures typical in scrubbers, odor control units, and chemical treatment systems.
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