Hookup for high temeperature

[dearkd]

Dear all,

I have to use remote seal pessure transmitters(2" flange connection) in toxic service.

Temperature is 450 Deg. C.

Now available fill fluid is DC 704 which can withstand 330 Deg C.

To reduce temp, i am planning to put spool piece.

However, i am unable to decide length of spool piece which can have some basis to convince my client that temp can be brought down with xxx spool length within 330 Deg. C.

If any body came across this situation or having idea/solution for this situation. Please share.

Thanks

Kaushal