Static electricity and rotameters.

Inaccuracies in Rotameters, caused by static charges, seem to be relatively common. Inaccuracies can be of a very serious order. Charges outside the tubes can be removed easily by antistatic spray. Charges inside the tube are very difficult to remove except by dismantling the apparatus or by the use of a radioactive pistol. Charges have been measured and are much larger than had been supposed and could cause an explosion if cyclopropane is being used. A possible mechanism for the occurrence of the internal charges has been investigated. The manufacturers are co-operating in the design of a tube in which these charges cannot occur.