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Does anyone know anything about a 1998 revision to ASME BPVC Section I which changed the stress factors used when calculating boiler tube minimum wall? What does it take to get approval to use these factors on a pre-1998 boiler? Jurisdictional approval?

Thank you.

Thanks, Johnny!

I have a 3600 rpm, double suction, pump with impeller wear rings that are approximately 7.375" diameter. Can anyone tell me what the proper clearance should be in this application? Fluid temp. is 250F. Thank you.

We have a 30 hp, 1800 rpm, 480V, 3ph motor that drives an inclined screw conveyor that has been causing issues. At full capacity the motor trips out on overload at times, but has not done so at this capacity in the past. It has always run fairly high load at this rate (90+ % fla), but has not...

Sorry, rb1957, you posted as I was writing my last post. I think I'm all set now. I will go after the tapered loading and try to optimize the stiffener use to meet all the objectives. Thank you sincerely for you patience and help.

OK. How about the units used for p and a? in, psi, ???? Are you telling me that the equation from Figure 34 is spitting out kip-ft/ft?

Once I am satisfied with the stiffeners, I just want to be able to show that I concidered what the peak stress is in the plate between the stiffeners. Yes, stiffeners are more efficient (in terms of material used). Consideration #2, cost and time to fabricate $$$$. Stiffeners take more time in...

Miecz, I understand that the coeff. is unitless. So p is (psi) and a is (in)? You said the moment in my case is 1.90 k'/ft. Do you mean 1.90 kip-ft? I'm tripping up on the units in the formula on Figure 34, Moment = Coeff. x (p x a^2). What are the units for Moment, p, and a? I know this...

I agree with this approach fully. My only motive in econimizing on stiffeners is weight. This structure has to be rigged out 180' over the inlet of a dam, so crane size $$$ is a consideration.

Ok, I see what you mean, miecz. Can you help me with the units that should be used in the formulas stated in the publication you referenced yesterday?

Omer Blodgett, "Design of Welded Structures" has the Roarke's formulas I need, Section 6.5 - 3, Table 1. Thank you.

Yes, I am adding stiffeners. I am just having trouble with the analysis of the plate, specifically with the units used in the tabular coefficient tables from the publication that miecz referenced. I do not have a Roark's to reference, so I only have the a/b = 1.5 formula that you kindly offered...

rb1957, by reduction of the stress, do you mean from the maximum stress obtained when two of the sides are assumed to be detatched? On my earlier post I was asking for assistance with the units used in the publication referenced by miecz earlier. I downloaded the publication from the Dept. of...

Ok, I thought I was heading the right way with this. I guess I do not understand the units used by the above publication. For plates fixed on all four sides and uniform loading. Moment = Coeff. x p x a^2. What are the units? I have tried the correct table (I believe), but I can not replicate the...

Thanks. Looks like the solution. I agree, why would there be a hinged condition all sides? They covered everything else. I thought there must be a fair amount of work done on this problem. I have run into this before and never felt quite comfortable with my method. My only solution was to...

P.S. Thanks for the help. I wish I had a Rourk's to look at.

The plate area I am trying to analyze is 4' x 6' and is welded out 100% to a frame of channel and wide flange members (it has to seal out the water). The pressure is pushing the plate against the frame. If I had a way to look at the maximum moment in the plate I could design backing members for...

I'm looking for a little help in determining the proper bending equation to use in the analysis of 1/2" plate welded out around it's perimeter to a structural frame. The frame is submerged and is used to isolate a gate on a hydroelectric dam for maintenance. I was able to analyze the structural...

Can't say much for eliminating the desuperheating as far as the erosion/corrosion problem goes because the unit is in service so I can't readily measure the rate of material loss. What I can say is there is too much superheat to leave the desuperheating off. The temperture without superheat...