An assessment of the TM3 gas differentiator.

The TM3 Gas differentiator, a simple device introduced to differentiate between nitrous oxide and oxygen, was found to be capable of positively distinguishing between these gases when only they were known to be present. The differentiator gave nearly equal responses to nitrous oxide and carbon dioxide. Cyclopropane, halothane, methoxyflurane, trichloroethylene and nitrogen all produced smaller responses on the differentiator's built-in meter. This apparatus has proved in use to be a practicable and simple method of checking the composition of gases emerging from pipelines.