Chlorine Gas Feed Systems – Repair & Troubleshooting by Montana Disinfection Expert Doug Mitch

www.ablewright.com

It is critical that chlorine gas feed systems function properly. When a formerly good system goes bad it can be frustrating to determine the cause, as there can be many issues involved. In the following we provide some repair and troubleshooting tips for operators…

1) Booster Pump Flow - Check the output of the booster pump, or high pressure source, to be sure the flow (gal/min) and pressure (psi) delivered to the ejector is sufficient. Confirm the requirements from the manufacturer´s nozzle curves. Without sufficient flow and differential pressure, the ejector will not develop enough vacuum to actuate the regulator and draw in the gas. Obstructions in the discharge piping?

2) Venturi Ejector - Check for debris in the nozzle, vacuum passages, or check valve. The clearances in these passages is very small, and can easily trap sand, metal filings, pipe cuttings, and other debris. A wye strainer located upstream of the ejector can minimize the potential for this problem.

3) Liquid in Vacuum Lines - If the check valve does not close completely on shut down, liquid can migrate into the gas vacuum tubing and components. In some cases, it may be necessary to utilize an "Anti-Siphon Valve" downstream of the ejector. Super-chlorinated water is very corrosive and can quickly stain and damage gas feed system components.

4) Vacuum Test - With the chlorine cylinder valve closed, open the meter rate valve 2 to 3 turns and start the ejector booster pump. The meter tube ball should drop to the bottom within about ten seconds. If the ball continues to bounce there is either a leak at the lead cylinder valve gasket, or a loose connection at the vacuum tube fittings or meter tube.

5) Vacuum Leaks - Check all tubing connection fittings (both ends) to be sure they are tight and leak free. Unfortunately, vacuum leaks are almost impossible to hear and very difficult to detect. It is usually best to start at the ejector tubing connection and work your way upstream through the system until you identify and cure all the leaks. Sometimes a temporary vacuum gauge is useful.

6) Vacuum Regulator - The inlet valve assembly can become obstructed with debris, causing poor regulator performance or gas venting. Carefully check the inlet filter when changing gas cylinders and replace the filter floss or element as appropriate. If debris gets into the internal mechanism of the regulator it can cause a dangerous situation, necessitating rebuild or replacement.

7) Maintenance & Cleaning - System components (ejectors, meter tubes, rate valves, etc.) can become clogged with mineral hardness, stains, and corrosive deposits. After properly removing the component from the system, it can usually be cleaned by carefully dismantling and soaking the affected parts for 5 minutes in muriatic acid or commercial products like "CLR or "Lime Away". Pipe cleaners are helpful in meter tubes and small passages. It is recommended that all operators keep preventative maintenance / rebuild kits or spare components on hand.

8) Safety- We recommend that chlorine gas be fed only using a vacuum system; never fed under pressure. If a chlorine gas pressure leak develops in your system, it should be immediately shut down at the gas cylinder valve and the area evacuated until the equipment can be safely serviced. Chlorine gas can be very deadly and should be handled only by trained operators with extreme caution. For additional safety information, consult the Chlorine Institute: www.chlorineinstitute.org and your equipment manufacturer´s recommendations. Be Safe - Safety Pays.

Doug Mitch is the founder and President of Able Wright, Inc. – a provider of water treatment equipment and technical services, specializing in disinfection and chemical feed for Montana, Wyoming, Idaho, and Washington. www.AbleWright.com