Blade dampers generate fewer noise and come in two styles: parallel and opposed dampers. Parallel blade dampers: Their blades transfer in a similar route and retain the airflow. Handbook dampers are modified by hand and are typically Employed in older HVAC systems. They may be much less frequent right now https://aircontroldampersforengin68901.blogsmine.com/37063357/the-definitive-guide-to-air-control-dampers-for-hot-climates