mechanical seal selection

[farahnaz77]

when "A" letter is used as third letter in mechanical seal code as per H-7 appendix of API 610? what about "T" ?

 

[pmover]

for 3rd letter...
T - throttle bushing with quench, leakage, &/or drain connection.
A - auxilary sealing device; to be specified.
P - plain, no throttle bushing.

good luck!
-pmover