Variable Inlet Vane Dampers for Fan Inlet Volume Control
Air Systems fabricates custom variable inlet vane dampers in mild steel and stainless steel to bolt directly to your fan manufacturer’s inlet flange for manual or automatic volume control.
Pre-spinning the air entering the fan eye delivers a 4:1 volume turn-down ratio at constant peak static pressure — without the energy waste of throttling downstream.
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- Turn-Down Ratio
- 4:1At constant peak static pressure
- Static Pressure
- 0" to 51"+Three pressure ranges available
- Actuation
- Electric · Pneumatic · Hydraulic2-position or modulating control
- Materials
- Materials of ConstructionMild Steel, Stainless Steel
Fan inlet volume control applications where throttling downstream wastes energy — VIVs pre-spin airflow entering the fan eye for a 4:1 turn-down ratio at constant peak static pressure.
How Variable Inlet Vanes Are Built & Configured
Throttling fan volume with a downstream damper wastes energy because the fan still runs near full load. A VIV pre-spins the air entering the fan eye, reducing the energy needed to move it. Every unit is fabricated to your fan manufacturer's inlet flange bolt pattern and diameter.
- 01 4:1 turn-down ratio at constant peak static pressure
- 02 Static pressure ranges of 0" to 25", 26" to 50", and 51" and above
- 03 Imperial and metric sizing with custom bolt hole patterns
- 04 Built to your diameter and flange bolt pattern for any fan manufacturer
- 05 Electric, pneumatic, or hydraulic actuation, 2-position or modulating
- 06 Galvanized, aluminized, galvanneal, and stainless steel, with enamel, epoxy, and powder coat options
Why Air Systems
VIV selection means matching vane diameter, rotation, static pressure range, and flange geometry to a specific fan — and those vary by manufacturer and model. We have built VIV dampers for fan inlet applications for over 20 years.
In-house fabrication and design staff provide drawing turnaround and material selection guidance during the proposal process. Typical lead time 3 to 5 weeks, with expedited delivery available.
Frequently Asked Questions
What turn-down ratio can be expected from an Air Systems VIV?
The VIV provides a 4:1 volume turn-down ratio while maintaining the same peak static pressure.
What information is required to receive a VIV quote?
Provide inlet diameter, airflow in CFM, maximum fan static pressure, airstream type, and normal and design operating temperatures.
Can a VIV be fabricated to match a specific fan manufacturer's bolt pattern?
Yes, any fan manufacturer's flange size and bolt pattern can be accommodated.
What is the typical lead time for a variable inlet vane damper?
Lead time is typically 3 to 5 weeks, depending on actuator lead time, with expedited delivery available.
Get a VIV Built to Your Fan
Provide your fan inlet diameter, airflow in CFM, maximum static pressure, fan rotation, and airstream type and get a detailed quote within 24 hours.
- Fan inlet diameter and flange bolt pattern
- Airflow (CFM) and maximum static pressure
- Fan rotation (clockwise or counter-clockwise)
- Airstream type and operating temperatures
Send Us a Sketch
Give us the duct diameter and a photo or sketch — we'll spec your damper. Detailed quote within 24 hours.
We don't share your information. A factory application engineer will follow up directly.