Loads on suction nozzle conn. & combined resultants per NEMA fails

[MQM90]

Dear All,

We have already procured a steam turbine and its existing piping is being checked by piping specialist. The loads on suction nozzle connection and combined resultants (i.e. Limit 3) are not passed as per code NEMA SM 23.

I just want to get some sort of help or any engineering opinion to get the piping loadings and its impact reduced on suction nozzles according to the standard.

One idea is to make all support’s friction factor reduced by using Teflon or any other material that reduces the friction factor between the pipe and structure, because adapting above technique the turbine nozzle loadings as per NEMA SM 23 is within the limits.

I also want to confirm above engineering technique is viable in steam turbine piping or not recommended?

Appreciate your relevant help in above context.

Best regards,


Osama Nusrat Ali

 

[SNORGY]

You could do the roller support as described, but Grinell and / or others could give you a properly engineered rolling support.

Otherwise my preference is graphite pads.

Regards,

SNORGY.

 

[MQM90]

Thankyou SNORGY

You are great !!!

Graphite pads is final but i am interested to know that rolling supports though give minimum friciton of coefficient i.e. steel balls to steel rails 0.005 but is not a very good idea as the pipe friction forces are tremendously reduced which finally makes the piping system more flexible then required.

I wish to know the practicality using the rolling support on high temperature turbine piping and making the piping system relatively more flexibile.

Osama Nusrat Ali