Demin. Water Tank - Top or Bottom Inlet? 3

[InDaPass]

I am building a new demineralized water tank to supplement an existing tank. The existing tank has the inlet at the top. Going into the top of the tank increases cost by adding a long stainless steel riser to the top of the tank. Are there good process reasons for doing this?

The tanks will be fed by ion exchange demineralizer trains. Is it beneficial to have constant back pressure on the demin. trains? Are there other reasons for placing the inlet at the top of the tank? The two tanks will have separate inlet headers which are not hydraulically linked.

 

[mbt22]

One possible reason is to provide a nice air gap to prevent back flow. The run of pipe is probably cheaper (and more reliable) than a check valve.

Matt

 

[unclesyd]

You definitely don't want a waterfall in you DI tank to pickup more O2. Pickup from the surface is bad enough. We have conservation vents on our tanks to blanket them with N@.

As I recall we make and take from the lower part of the tank just above the bottom.

 

[MJCronin]

The purposes of an internal fill pipe are to:

- Reduce foaming for certain liquids

- Reduce dangerous static charge build-up for other liquids

- Prevent shell erosion (for H2SO4 and similar liquids)

and of course, when combined with a siphon beaker hole backflow can be prevented.

I see no reason for a riser pipe for this services...

Anyone ???

-MJC

 

[bimr]

Agree with the comments of the previous two. There is absolutely no reason to have a fill pipe. When the demineralizer system shuts down, the demineralizer valves also shut off.

The biggest concern with the tank is absorption of carbon dioxide and oxygen from the air into the water.

Most systems do not have a top fill. Unless of course, you are filling from a gravity tank, like an old steam engine.