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ammar20030 (Electrical)
4 Jun 10 17:33
Guys,
I am new to this cryogenic. I was reading the standard MSS SP-134-2006a "Valves for Cryogenic Service Including Requirements for Body/Bonnet Extensions" and i came across two terms
1) "Cold Box" Extension
2) "Non-Cold Box Extension"
According to the standard :
Cold Box Extension defines that the operating mechanism of the valve is outside the cold box which makes sense
but what do you mean by non-cold box ?
In standard non-coldbox is defined as "A body/bonnet extension that is used for valves that are normally individually insulated "
What does this mean ? When you do the cryo test according to BS 6364:1984 , the valve is placed inside an insulated box and the operating handwheel or gear is outside the box. Evrything inside the box is insulated but how can you have a cryogenic valve that is individually isolated? I am just getting confused in the difference. 字串2
Also in the standard Table 1A , lengths for non-cold box stem/bonnets is shorter than the cold box.
Please help..
iainuts (Mechanical)
4 Jun 10 17:52
A cold box is a relatively large box that has valves, pipe, vessels and other components inside. Valve handles will extend outside this box.
In comparison, individually insulated simply means that the valves and pipe have insulation around them but they are not inside a box. Imagine a long length of pipe extending 100 feet in a straight line with a couple of valves on it. You wouldn't want to put a box around this. Instead, you put cylindrical insulation around the pipe and similar insulation around the valves.
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