Smoke tubes
A smoke tube is a simple flow tester that visualizes the smallest air currents . Areas of application are e.g. B. mining or laboratory environments .
The widespread form consists of a glass tube, inside of which there is fuming sulfuric acid in granules . For use, the glass tube is broken open at both ends and air is pumped through. The reaction of the sulfuric acid with the humidity in the air produces a white smoke, the movement of which indicates the air flow.
In the simplest case, a rubber ball serves as the pump; but there are also electric pumps for this purpose. Use with compressed gas is problematic due to the lack of moisture in the gas.
In some cases, manufacturers include rubber stoppers in order to be able to close the tube again for a short time.