Rupture Disc for Hot WFI storage tank 1

[funsharer]

We will install a rupture disc(single acting, positive only) on a Hot WFI storage tank. The tank was manufactured according to ASME code and is designed for full vacuum and equipped with a vent filter ( 30" x 3 poles on 2" nozzle). We will use the tank for hot water application only.
I read a article about rupture disc and it says that any tank used for storage of hot water should be equipped with a compound type rupture disc just in case.
I doubt if there is a chance for the tank to be exposed to cold application( Not sure about it as I do not have any experience with this.
I really wonder which is the best choice.

Please help me with this.

Thank you,

John

 

[greg87]

Since your tank is rated for full vacuum there is no reason to use a disk to protect the tank against vacuum.
Not sure what kind of "hot water tanks" were being referenced in the article you read.
Your vent filter should be properly sized to ensure that enough air can come through during withdrawal of liquid, or other cases - collapse of steam if you steam sterilize(?) etc.that could create some vacuum. Vacuum is to be avoided to prevent possible leakage of (contaminated) air through joints, but this has nothing to do with protection of the vessel.

 

[funsharer]

Greg,

Thank you for your kind advise.
I think you got a point.
However, I am still concerned that the WFI storage & distribution system has Ambient water returning from use points and it could cause a full vacuum in a way.
It is designed for full vacuum , but we don't want to expose it to full vacuuum as we are not sure what is going to happen with the vent filter flugged.
I guess it is a good idea to spend some money to protect a very important and expensive equipment in the long run.

Please let me know your further idea.

Thanks,

John

 

[abcmex]

John,

Probably you would like to avoid vacuum to reduce the risk of external contamination and to avoid reducing the NSPHa for the pumps. I suppose that you have a Rupture disk and a sterile vent filter and a pressure indicator (for sterilization). You may use a manometer with a low pressure alarm.

RGS

 

[dtreacy]

Hi,
All the above replies sound good. I can only add the following
Fit a heat tracing mechanism onto the vent filter housing to stop condensation blocking the filter and causing a loss of filter integrity during periods of vacuum / high differential pressures.
Have a mechanism in place to periodically test the integrity of the vent filter (bubble point).
As for your rupture disc, it should be adequately sized for the tank and design to rupture at -5% or -10% of the positive design pressure of your tank.
Another good practice would be to fit a rupture disc breach senor to allow immediate detection of a tare in the disc.