Chlorinators

Vacuum Chlorinators

The most typical kind of chlorinator, a vacuum chlorinator, is shown below:

In a vacuum chlorinator, chlorine gas is pulled from the cylinder into the source water by a vacuum.  The vacuum is created by water flowing through the injector and creating a negative head.  This negative head forces open the pressure regulating valve on the cylinder and allows chlorine gas to flow out of the cylinder and into the chlorinator. 

Once the gas has entered the chlorinator, the chlorine feed rate is measured using an indicator known as a rotameter.  Just beyond the rotameter, the chlorine gas flows past a regulating device (a V-notch plug or a valve) which is used to adjust the chlorine feed rate. 

Then the chlorine gas is pulled into the injector, also known as an ejector.  The injector consists of a pipe filled with flowing water.  The flowing water pulls chlorine into the water, both chlorinating the source water and creating a vacuum in the chlorine line which pulls more chlorine gas out of the cylinder.  This type of chlorinator is also known as a solution feeder since the chlorine gas is dissolved into a small amount of source water, which is then piped into the main line of water to be chlorinated. 

Chlorinators can be controlled manually (using the regulator) or with a controller.  The most common type of controller is the flow proportional controller which automatically feeds chlorine based on the flow rate of the water. 

Vacuum chlorinators are very safe since any break in the line with disrupt the vacuum and close the pressure regulating valve.  As a result, chlorine leaks are very uncommon. 

Direct Feed Chlorinators

In a few cases, direct feed chlorinators are used instead of vacuum chlorinators.  In a direct feed chlorinator, the chlorine gas is under pressure and is pumped directly into the main flow of water.  There, the chlorine is evenly dispersed into the water using a diffuser, like the one shown below.

Since the chlorine is under pressure, a pressurized water supply is not needed for use with a direct feed chlorinator.  However, the pressurized chlorine is prone to leakage, so safety issues limit direct feed chlorinators to small installations or for use as emergency equipment.