Vacuum feed chlorinators are suitable for dosing chlorine solution in gravity-sumps, reservoirs and open channels. It is also suitable for pressure main dosing where the chlorine solutions are injected into the pressure main. In vacuum feed chlorinators, the vacuum created by a flowing water stream through an ejector motivates the chlorine flow from the pressure cylinder. The chlorine regulator and flow meter are located between the ejector and chlorine cylinder. The vacuum developed by the ejector pulls the chlorine gas through the flow meter.