Ninty percent level alarm design questions

[Tankerguy]

What is the best way to install an ATG so the 90% alarm will work for more than one tank?

The reason for the question is that there are so many ATG systems which will fail to alarm once one tank on the console is triggering a 90% alarm and a second tank reaches a 90% level while the first tank's product is still high. The alarm will sound for the first tank and the annunciation will be silenced by the "Reset" button at the fill location. However, the relay in the console will remain in the closed position because the first tank is still in a 90% high level condition.

When another tank reaches a 90% high level condition, there is no annunciation because the "Reset" button has been pressed and the console's relay is still closed.

Now the 90% full alarm is not functional.

Perhaps this is not the case with all manufacturers' systems? Please comment if you know of a system which does not fail in this scenario!

Also, please explain in detail if possible how a successful system functions. For example one brand system can function if there is one annunciator for each tank. However, in many cases only one annunciator is installed for an entire site with several tanks.

[cantdrive55]

I'd call the mfgr of the tank monitor you're interested in. I wouldn't trust anyone on here to give you a 100% correct answer, even myself. It's too big a gamble if you don't get the right info...

[CherokeeUST]

You could cure this issue by changing operational requirements. Only allow filling one tank at a time.

Or install flapper valves in each tank so the alarm is basically a backup.

[Techie]

What systems are you using? do you have a single Annunciator? where are you located? There are different methods depending on local requirements. For example, if you are using a Veeder Root system and are using 1 audible overfil and beacon it will acknowledge 1 alarm at a time outside. On the console you will have the alarms ringing. We use a multi lite overfil alarm box to lite up each tank that is in alarm, if there are more than 1 tanks in an overfill condition. Give us more information, and always check your local requirements. These examples work for me in my area.