What is Steam out condition? 4

[samkor]

Dear Friends,
I am working on Pressure Vessel design.
in my design there is one condition " Vessel Steam out condition@150 Deg. C.
i would like to know what is this condition?

Thanks,

 

[bhushan76]

Purpose of steam out is only cleaning. For equipments where presence of any impurities like grease,paint traces etc are unacceptable , steam out is specified.

Some vessel design specifications will ask you to account of vacuum design condition whenever steam out is specified. Some specifications are silent about this because a adequately designed vent nozzle if left open while steaming out will not allow vacuum condition to occur.

A point to note is that steam out condition specified in your post does not have any mention of pressure.So if your vessel design spec is silent about this, i assume you need not consider vacuum design unless called out somewhere else.

 

[jamesl]

In a steam out condition, if the steam condenses when the temperature decreases, and there is no opening on the vessel for air to come in, it will pull a vacuum in the vessel.

Some vessel specs require partial vacuum design for steam out; some require full vacuum; and some are silent. In your case, it seems the Buyer wants you to design the vessel for partial or full vacuum.

 

[Duwe6]

Also, to design for "Steam-out", you have to know the max pressure of the utility steam that is going to be used. This will give you a Design Temperature, and it may be higher than the Vessel was planned to be designed to. Looks like they are giving the Design Temp for your "Steam-out"

 

[TVSN]

To be more specific, during steam out the steam will be sent inside the vessel for cleaning during the maintenance as explained by Mr.Bhushan above, once steam is sent in, some portion of the steam will get condensed inside the vessel, during condensation some vacuum will form inside the vessel, atmospheric pressure contributes towards this vacuum (partial or full needs to be informed by the purchaser), thats why the steam out condition is considered as the external design conditions.