Hi Cessh,
Both vibration and overheating are caused by a defect. The vibration does not cause the overheating, the defect does. The symptom that is vibration will be observed earlier than the temperature increase in a ball / roller bearing. You would be able to detect the defect symptoms in...
GT,
What model of ABB/Alstom unit is it?
We have some GT11N units that had Alstom issued bulletins about EGH cracking.
Construction on the EGHs was flimsy in certain critical areas, leading to in service cracking.
They have modified parts and a spring canister support for the EGH now to remedy...
Hi Dik,
That's correct.
I select the closest available Crosby G-209 shackle for the load.
The next available drill size will be used to make the hole slightly larger than the pin.
AMSE BTH-1 accounts for the difference in diameter between the pin and the hole.
Regards,
Hi All,
Thanks for your help.
WillisV, Agreed, this makes sense to me despite being a mechie.
NS4U, The 2008 version of ASME BTH-1 I am using is commented and most calculations refer to AISC. I beleive that the ASME code mostly describes certain cases covered by AISC.
dhengr, I will post...
Hi JAE,
Thanks for the reply.
I don't have AISC's table B4.1 however it seems like ASME BTH-1 table 3-1 has a similar entry.
"Legs of single angle struts; legs of double angle struts with sparators; unstiffened elements, i.e., supported along one edge"
Which has the following limits for...
Hi Everyone,
Baseed on thread507-273125, I am working on designing a standardized set of lifting lugs using ASME BTH-1-2008.
For now, I am working on a single case and detailing the calculations.
The lug is as per figure C3-3. I have also attached a sketch.
I need to vary the angle of the...
Hi Z,
Here is the literal translation (I'm a Canadian francophone):
The position of the joint plan, injection points and ejectors will be subject to acceptance.
material: Black ABS
Hi dharhay,
google "commtest vibration primer" the first result is a downloads page.
On that page there is a beginner's guide.
It will help with most of your questions if I remember correctly.
I'm sure other companies have these as well.
Regards, MM
Hi Humbug,
We make that decision on a job by job basis.
I work in a power plant where during an outage we have many contract welders. So we look at the welder's performance on past RT jobs and the job schedule to make the call.
Like it was said above, when you have time to deal with...
Hi drawoh,
I agree.
ACME threads are usually made as self-locking because they are a power screw. I still suggest checking for UNC because their use as a power screw is not what they were made for, therefore they won't necessarily be self-locking.
Thanks for clearing that up for me.
Hi Steris,
"Self-locking refers to a condition in which the screw cannot be turned by the application of an magnitude of force applied axially (not as torque) to the nut."
Machine Design by Norton
I can't confirm about the UNC being self locking or not, analysis is required to confirm or there...
Hi Steris,
What wasn't discussed is that power screws like an ACME would most likely be self-locking while a UNC likely would not be.
This may be a very important feature in your application.
TCPhoenix,
Alstom is a direct competitor to B&W for boiler work.
They have always been good for us.
They have the type of experts that I would go to for this type of project.
Good Luck.
I totally agree with KenA. Usually the maintenance contractor for the safety valves will guarantee no chattering for up to 90% of the set pressure.
If your operating pressure is above 90% of the set pressure, the contractor won't be able to help if you see chattering.
Hi kb44,
Be extremely carefull with your PWHT tempearture profile for 91 material. They must be dead on.
Hi MJ,
I think he/she means the radius of the elbow is 3x the diameter of the pipe.
