A flow meter is a device used to control and measure the amount of gas passing through a Hydro Instruments chlorinator or sulfonator device. It consists of a tapered glass tube with an entry point in the bottom and exit point in the top. Inside is a “floating ball” which is designed to move up and down in the tube when supported by the gas flowing through it. In the top of the tube is a screw down rate valve which variably controls the size of the gas outlet orfice, thereby controlling the feed rate.
Gas pressure passing through the tube supports the ball. More gas flow pushes the ball higher and vice versa. Therefore, the rate valve setting at the top of the flow meter tube controls and the ball measures the amount of gas flowing through the meter tube, and consequently, through the chlorinator/sulfonator.
The size of the tube has the largest absolute control over the maximum amount of gas that can pass through the flow meter. Therefore, a Hydro Instruments chlorinator/sulfonator rated at 100 PPD uses a different and larger flow meter than a 50 PPD chlorinator/sulfonator.