Chinese Diesel Heater Small Burner Air Intake Duct

Things that I have made as experiments on my Chinese Diesel Heater.

This bellmouth will help to quieten the noise made by the air being sucked in to the burner air duct.
Air doesn't like to be quiet when sucked in around sharp edges, this bellmouth will smooth the airflow out.
It will not quieten the  high pitched noise from the heater fan itself.
It will help very slightly with efficiency as well.
Not to be used directly on the heater as it will melt, but at the end of the 25mm burner air inlet pipe.
Different inlets provided so you can choose the version that fit's your intake pipe - 25/ 25.25/ 25.5/ 25.75 & 26mm
Simply glue the “Bellmouth” part of the print in to the “Bellmouth Inlet Tube for 25mm Duct” and hey presto.