Gauge hatch on pressure dome roof tank

[Syahar1975]

Dear experts,

Demineral Water Tank with nitrogen blanket and operating pressure 8 mBar. This tank has 8" nozzle for gauge hatch. Gauge hatch is used for water sampling.

I don't understand why 8" gauge hatch is required for this tank.

Any explanation is highly appreciated.

Syah

 

[MJCronin]

A gauge hatch is an ancient device, originally used to drop a long stiff stick into a tank and "gauge" the level of the liquid contained.

It is not meant for sampling ..... IMHO ..... and a poor choice for inclusion in a demin water tank design

Would it be possible to sample the demin water some other way ???

MJCronin
Sr. Process Engineer

 

[IFRs]

"I don't understand why 8" gauge hatch is required for this tank."
"Gauge hatch is used for water sampling. "

Seems to me you answered your own question.
Is there another question there somewhere?

 

[Syahar1975]

MJ Cronin and IFRs,

Thanks for your response.

My concern is there is a pressure inside the tank that need to be maintain for one or some reasons. There is also N2 blanket above the product.

If one day the tank operator open this gauge hatch then the pressure will drop to 0 and N2 will come out suck the O2 around the operator unless he is using SCBA.

I saw in one of my previous projects sampling nozzles installed on the shell at various elevations. Yes, there will be cost factor by installing these sampling nozzles.

Syah

 

[IFRs]

If there are insufficient engineering or administrative controls and an operator could be exposed to a significant hazard, it may be appropriate that different controls be added or used. Locking the hatch or removing it and installing sample nozzles sounds like a different and possibly better approach. What if a nozzle that is above the liquid level was to be opened - is that a similar risk? Can sampling be eliminated altogether?

 

[bimr]

There is no need for a gauge hatch on a demineralized water storage tank.

I would suggest that the gauge hatch was added to the design drawings by an inexperienced engineer or designer.