Hi All,

I m new to PVElite and have some following Queries towards this software :-

1) In Status Bar, how software is computing the value of "Trext". For eg. if Int. Pressure & Temp. is high than Ext. Pressure & Temp. than the value of "Tr" should be greater than "Trext", but generally "Trext" is greter than "Tr". So plz tell what z the concept behind taking the values of "Tr" & "Trext".

2) In Design Constraints, the value for "MDMT" can we take the ambient value?

3) In Saddle Input, what is the Saddle Dimension 'a' means.?

4) If we have taken a material from database of ASME VIII Div-1, and then doing analysis acc. to PD:5500.. is it Possible.?


5) If i had design a model in PVElite and want to check its every element in CODECALC-2010,so it can open it automatically in Codecalc?? or we have to give the inputs again in Codecalc.???

Kindly provide me the answer for my Queries ASAP.


thanks & Regards,

Ashutosh.

Hi there,

I'll try to give you some answers.

1. "Trext" and "Tr" is calculated acc. design code. So if you are using, let say, ASME div 1, then you can check the formulas in UG-27 & UG-28. There you can see everything. Same is for other standards.

2. Of course you can use ambient value.

3. Distance "a" is the distance from saddle center line to the nearest ref. line/element. Press F1 while your cursor is in that text box and help about that explanation will pop up. You can use this method for every field you don't understand. Just select the field and press F1

4. It shouldn't be possible, but someone else should confirm this one! Because the logic of using pvelite is to select design code first and then do the rest. If you choose PD5500 you'll see that you can't choose asme materials at all. And I think that PD5500 uses different values of Rm, Rp then ASME does.

5. As far as a I'm familiar with this, you must enter all values again in codecalc.

Regards.

Dear Sir,

Thank u so much for your answers. According to you in 3rd point, the saddle dimenstion 'a' is :-

The distance is the length between the centerline of the saddle support and the tangent line of the nearest head. This dimension is usually labeled A in most pressure vessel texts.....it means the distance from "From" Node to saddle is same as Saddle distance 'a'.

Also i had gone thru the UG-27 & UG-28 for Trext :- plz tell me, Is this value of "trext" is computed only due to External pressure or its the combination of both Internal & External pressure...

Also plz anyone clear my 4th & 5th Queries....

waiting for your reply....

regards,
Ashutosh

Hi,

regarding distance "A", it doesn't have to mean that.. If your shell consists of several parts, then it don't have to be the distance from "from nod"..

Regarding thicknesses. Tr = Thickness Required (for internal pressure)
Trext = Thickness Required External Pressure.

If you enter in design constraint external pressure as well, you'll have both calculations for internal/external pressure... and the governing thickness is the greater one.

Regarding materials check this
http://65.57.255.42/ubbthreads/ubbthreads.php?ubb=showflat&Number=38137#Post38137

It is the same.. You can't use it as you wish.

And about codecalc I'm 98% sure that you have to enter values again.


Regards.

Hi,

1) Actually when we make a model of Horizontal Vessel with SADDLE inputs and by changing the values of Saddle Distance 'a' in input there is no changes occur in Graphic model.Is this distance will not show in the model and will affect only the analysis??????

2) Also for "Tr" & "Trext", if we take a e.g:- Int.Pressure:- 240Kpa, Int Temp.:- 75 degree C, Ext. Pressure:- 101.325Kpa, & Ext. Temp.:- 35 Degree C.....then "Tr" is less than "Trext" value.. is the calculation is right...???

Dear sir,

you should pay much more attention to the calculation report instead of trying to force 3D model to look like you wish. At the end that software is just human creation and it is impossible to make 3D model exactly as you wish.

Run the calculation and go to the "Horizontal Vessel Analysis" and you'll see the value of "a" and stresses as well, and you can compare them.

So, my answer to 1) is "YES", 3D model isn't changed while analysis is correct.

2. To answer to this question I (or who ever) need to take a pen, calculator, ASME Section and to do manual check of software. So far I have not been familiar with PVELite's bug regarding thicknesses. So if you need to know if the calc is correct, you should take ASME Div. 1 and Section D for materials and go through calc. manually. But as I said so far Pvelite's calculations regarding thicknesses have been correct which means "YES, calculation is correct".

All in All this is just an software made by humans to help other people in their work. Everything, that is behind those cute windows, you can find in ASME, PD, EN, BS...etc.. They didn't invent hot water after all. You should keep this in mind, if you are not sure in something. And you can easily check everything by hand.

Regards

Dear Sir,

Thank u soo much for your kind support.

One more question I have, Is there any possibility of "UNDO" & "REDO" options in PVElite???????

Hello

First of all, thanks for the lively discussion.

Alas, at the moment, we do not have an undo button.

Yes, this is good exchange, thanks kodzak81, you can very correct, an engineer should be able to verify what the software produces.

The saddle dimension 'a' is used in the calculation, if you have a heat exchanger it would be distance to tubesheet/flange/tangent point of the head etc. any thing stiff that helps the vessel cross-section stay round.

If you change the distance from "From node", that is distance of the saddle from beginning of the shell section on which the saddle is located, then you will see the change in graphics.

Hi All,

Thanks for your kind support towards discussion, it helps me lot.


regards,
Ashutosh