Related Acessaries, Technical Features Overview

An inlet ring improves fan efficiency through aerodynamic optimization of the intake flow path. Without an inlet ring, air entering the impeller experiences abrupt directional changes and separation losses, which reduce the fan's ability to convert mechanical energy into useful airflow. The inlet ring acts as a nozzle, gradually accelerating the air and creating a uniform velocity profile at the impeller eye. This reduces incidence losses at the blade leading edges and minimizes recirculation. In PBM's internal testing, properly matched inlet rings contribute to maintaining the fan's peak efficiency across the operating range, directly supporting the energy savings that EC technology is known for — our EC motors already achieve efficiency up to 91%, and the inlet ring ensures that motor efficiency translates into actual system performance.

Selecting the right inlet ring involves three considerations:

• Impeller diameter match: The inlet ring throat diameter must match the impeller eye diameter. PBM designs each inlet ring specifically for its corresponding impeller size (e.g., 133mm, 175mm, 190mm, 220mm, 250mm, 280mm, 310mm, 355mm, 400mm, 450mm, 500mm, 560mm).
• Mounting configuration: Determine whether the inlet ring requires a flange mount, bolt-on attachment, or press-fit into your equipment panel. PBM can advise on the correct mounting bracket or adapter based on your application.
• Instrumentation needs: Decide if you need a standard ring or an instrumented version with pressure taps.

Contact PBM with your fan model number and application details, and we will specify the correct inlet ring part number for your setup.

PBM's EC fans are designed with integrated electronic control circuits that support two standard analog control signals: 0–10 VDC and PWM (Pulse Width Modulation). Our fan controllers use a 10K Ohm potentiometer to generate a variable 0–10 VDC control signal, allowing stepless (continuous) speed adjustment from minimum to maximum. This is the industry-standard control method for EC fans and is compatible with all PBM EC and DC fans that feature speed control input terminals. The controller also includes an ON/OFF switch integrated into the rotary knob for convenient local operation. For customers who need remote or automated control, our fans also support RS485/MODBUS communication protocol — compatible with IoT, smart building systems, and Industry 4.0 architectures.

The actual noise reduction depends on the fan type, operating point, and system configuration. Based on published test data from industry-standard installations:

• Centrifugal fans in air conditioners: Blade passing noise can be reduced by up to 9 dB, and overall noise level by up to 3.3 dB(A)
• Axial fans with HyBlade technology in heat pumps: Blade passing noise reduction of up to 12 dB has been measured
• Condenser applications: Noise level reductions of up to 16 dB for blade passing noise were observed in tests
• Air purifiers (RadiCal + FlowGrid combo): Overall noise level reduction of 2.8 dB(A) with blade passing noise down by 10 dB

To put this in perspective: a 10 dB reduction in perceived noise represents approximately a 50% reduction in perceived loudness. For B2B equipment manufacturers, this can make the difference between meeting or failing local noise regulations (such as EU outdoor noise directives) without expensive additional soundproofing.

An inline fan is a type of duct fan installed directly inside the duct system. In many applications, the terms "inline fan" and "duct fan" are used interchangeably.

However, “duct fan” is a broader category that may include:

• The FlowGrid is most beneficial in applications where noise compliance is a critical requirement. The top applications include:
• Heat pumps (air-to-water, air-to-air): Often installed in residential gardens or near property boundaries, strict night-time noise limits make FlowGrid very valuable
• Condensers and refrigeration units: Supermarket condensers and cold storage units frequently face neighbor noise complaints
• Commercial air conditioning: Rooftop units, cassette units, and central AC systems in commercial buildings
• Ventilation systems: Industrial and commercial ventilation where fans operate continuously near occupied spaces
• Air purifiers: For indoor air quality equipment in offices, hospitals, and clean rooms where low noise is expected
• IT and data center cooling: Server room cooling fans that run 24/7 and need to maintain acceptable noise levels

All of these align directly with PBM's target application markets, including Ventilation & Purification, Air Conditioning, Cold Storage & Cold Chain, and IT & Electronics Industry.