Technical Discussion-----Issue 13 (Rewards for active participation)
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The single exhaust fan has reached its maximum output; how can the second exhaust fan be connected in parallel when it is started?
Activate the second exhaust fan, meaning both fans will operate simultaneously; first, carry out the preparatory work before starting the second exhaust fan； Then, the second exhaust fan is started, and its outlet valve is gradually opened; simultaneously, the outlet valve of the first exhaust fan is gradually closed based on the existing air volume (this is done slowly to prevent large fluctuations in the exhaust air volume), until the load on both fans is equal.
When a single exhaust fan is operating at its maximum capacity, before starting the second exhaust fan, the unit’s load should be reduced so that the blades of the fan in operation are below the surge line that occurs when both fans operate simultaneously. Once this is done, the second exhaust fan can be started, and its blades gradually opened while those of the first fan are adjusted accordingly, until the opening angles and currents of both fans are roughly equal, at which point they operate in parallel
Agree with what was said on the second floor; the main considerations are matching and shock absorption
When a single exhaust fan is operating at its maximum capacity, before starting the second exhaust fan, it is necessary to reduce the unit’s load so that the blades of the operating exhaust fan are positioned below the surge line that occurs when both fans operate together. Only then should the second exhaust fan be started; its blades should be gradually opened while those of the first exhaust fan are reduced, until the opening angles and currents of both fans are roughly equal, at which point parallel operation is achieved.
The agreement with the view expressed on the second floor is mainly based on considerations of matching and vibration suppression. When the second exhaust fan needs to be started in parallel operation, it is necessary first to adjust the operating point of the first exhaust fan downward, keeping the furnace at a slight positive pressure. After that, the second exhaust fan is started; once it is running at a constant speed, the opening degrees of the air vanes in both fans are adjusted to be similar, so that the wind pressure and airflow of both fans are equal, allowing them to operate in parallel.
Answer: When a single exhaust fan is operating at its maximum capacity, before starting the second exhaust fan, it is necessary to reduce the unit’s load so that the blades of the operating exhaust fan are positioned below the surge line that occurs when both fans operate simultaneously. Only then should the second exhaust fan be started; its blades should be gradually opened while those of the first exhaust fan are reduced, until the opening angles and currents of both fans are roughly equal, at which point they can operate in parallel