Greetings everyone. This is the first blog I have created in which I will be discussing ‘Things I Have Seen Over the Years’. I hope you will enjoy the content and are welcome to post comments at the end of the blog.
During startup at a new cooling tower account, 110 gallons of an all organic scale/corrosion inhibitor product containing PTSA was delivered to a mini-bulk storage tank located near the cooling tower. The tower had a concrete basin below ground.
A new tower controller was installed that included pH, conductivity, and PTSA sensors. Chemical feed piping was installed prior to start up however one of the old injection tees and injection nozzles were discarded by the plumbing contractor as well as the old CPVC chemical feed piping where the injectors were located. The customer was anxious to get the program started so it was decided to temporarily feed the inhibitor chemical directly to the tower basin. This turned out to be a big mistake as there was no anti-syphon valve on the discharge tubing.
In the evening, when the service rep got home and used his laptop to access the controller, he noticed a high PTSA alarm. He checked the inhibitor pump relay and discovered that it had been off for several hours. He then looked at the PTSA trend graph and noticed it was continuing to increase! At that point, he realized the inhibitor was siphoning through the pump. A call was placed to the plant operator to remove the inhibitor feed line from the tower basin location and temporarily place it in the mini-bulk tank.
The rep visited the plant the next day with the new anti-syphon valve and injection nozzle and after installation, inhibitor feed was safely resumed. If it was not for the PTSA and remote monitoring capability of the controller, the entire 110 gallons of inhibitor could have been added to the system in less than 24 hours. Not a good way to start a new program with a new customer!