Reverse Air Dampers for Vegetable Storage Fans
Reverse air dampers close inactive fan openings in vegetable storage ventilation systems, reducing backflow, air leakage and uneven distribution in pressure channels.
Air Backflow Protection for Storage Ventilation Systems
Reverse air dampers are used in vegetable storage ventilation systems where several high-pressure fans operate into a common pressure channel or air plenum. When one fan is switched off, the open fan position can become an unwanted leakage path. Pressurized air from operating fans can escape through the inactive opening instead of moving through the crop or duct network.
A correctly selected damper closes that inactive path and helps keep the airflow where it is needed. This is especially important in bulk potato, onion, carrot and cabbage storage facilities, where pressure balance determines whether air passes uniformly through the stored crop.
Operating Principle
The damper leaves stay closed when the fan is not operating. When the fan starts, the airflow opens the leaves vertically, allowing air to pass with minimal obstruction. After the fan stops, the leaves return to the closed position and block reverse movement through the fan opening.
This simple mechanical function reduces uncontrolled bypass air and helps maintain stable static pressure in the ventilation system. It also protects the inactive fan zone from reverse airflow, cold drafts and dust movement from the pressure chamber.
Engineering Features
- Matched to fan sizes: the TKB damper range corresponds to common high-pressure fan sizes used in storage ventilation.
- Robust construction: treated quality wood is used for the main damper leaves, with massive hinges designed for repeated opening and closing cycles.
- Flexible installation: dampers can be mounted on a special pedestal around the fan or directly to the fan assembly where the layout allows it.
- Passive operation: the damper does not require a separate drive or control signal, so it follows the fan operating state naturally.
Available Sizes
When the Damper Is Needed
Reverse dampers become critical when fan groups are controlled step by step. In many storage facilities the automation system starts only the number of fans required for the current mode. Without dampers, inactive fan openings reduce the pressure available for the active air path and make airflow distribution less predictable.
The damper is a small part of the system, but it affects the efficiency of the whole ventilation concept. Correctly closing inactive openings helps the main fans work against the designed resistance of the crop stack, floor ducts or pressure wall.
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