Talk:Pressure vessel

message: The thin-walled pressure vessel formulas came from the Popov reference, though I'm not sure how to do citations.  Anyone think they're up to adding the necessary structure? - EndingPop 15:34, 12 December 2006 (UTC)
thread_title:  Citations 

message: In the US, when dealing with pressures, it is called gage pressure.  If you are from another country and want to make an argument that it should be "gauge" based on cultural differences, then do so.  Under no circumstances should it be spelled "guage". - EndingPop 18:55, 27 November 2006 (UTC)
replies: text: To clarify the above comment, EndingPop  is saying that the correct spelling is "gauge" when that term is used in say an article written in the UK. - mbeychok 19:24, 27 November 2006 (UTC)

text: I checked with www.dictionary.com (which is an american dictionary) and while both seemed acceptable, gauge seemed to be listed as the main version. I also did google searches for 'gauge pressure' and 'gage pressure' and I got 377,000 and 87000 hits respectively, and the first few for 'gauge pressure' were from American sites. All in all it seems to me that gauge pressure is actually correct to use even in the US. Given that, I see no reason to use 'gage'. Also see pressure which uses 'gauge pressure'.WolfKeeper 21:09, 27 November 2006 (UTC)
replies: text:  I am used to seeing "gage" from my fluid mechanics textbooks.  I would say that the results of your Google search aren't inherently conclusive, either, since "gauge" can be used in many other contexts not related to pressure measurement.  However, I also saw that pressure uses "gauge", so I would support that change for consistency with that page.  If the consensus is "gauge", then so be it, as long as it has been discussed. - EndingPop 01:33, 28 November 2006 (UTC)
thread_title:  Gage vs. Gauge 

message: This could really use the formulas for stress in thin-walled pressure vessels, and I'd add them myself, but they really need pictures to be informative.  My question is, does anyone know of a good way to make pictures that would be pleasing to the eye and useful?  Or, even better, of where I could find pictures that are already made for this purpose that are not copyrighted? - EndingPop 05:20, 16 February 2006 (UTC)
thread_title: Formulas for thin-walled pressure vessels

message: Including the word "boiler" as an example of a pressure vessel can lead to confusion. Yes, domestic hot water heaters are often called boilers and they are indeed pressure vessels. Small  boilers with  electrical heaters inside the boiler drum are also pressure vessels. However, large industrial boilers or power plant boilers are not simply pressure vessels ... they consist of a fuel-burning furnace, water-tubes, superheater tubing coils, reheater tubing coils, boiler drum (i.e., where the generated steam is separated from the circulating water), steam turbines driving a electricity generator, a steam condenser, a condensate deareator and a cooling tower. The only pressure drums are the boiler steam and water separator drum and the condensate deareator. I think that it would be much better to delete the word "boiler" and replace it with "hot water boiler" or "boiler drum". 
Likewise, the "See also" link of Boiler would be much better replaced with Water-tube boiler and Fire-tube boiler. - mbeychok 20:44, 6 July 2006 (UTC)
thread_title:  Boiler is a generic term for many different items 

message: Surely someone has a more sightly photo of a pressure vessel than the one that is now in the article! It looks as if it is in a junk yard. Does anyone have a photo of a pressure vessel in a refinery or a chemical plant or a natural gas treating plant?? - mbeychok 20:38, 3 August 2006 (UTC)
replies: text: I like old photo's but you can have a look at the German wiki, the problem there was that the best foto is a complete installation, maybe we should search on commons. Mion 21:25, 3 August 2006 (UTC)
replies: text: i placed a request on request images, nothing on commons. Mion 22:07, 3 August 2006 (UTC)
replies: text:  I am about to upload a new image ... see what you think of it Exit2DOS2000•T•C• 01:10, 12 July 2007 (UTC)
thread_title: Need better image

message: PD 5500:2006 Specification for unfired fusion welded pressure vessels 
:Is there a question there? Please clarify. And please sign comments on a Talk page by placing four tildes, like this ~~~~ at the end of your comment. That will automatically sign and date your comment. Thanks, - mbeychok 18:26, 19 September 2006 (UTC)
thread_title:  PD 5500 

message: Scalability: The article says that scale can't improve the M/V ratio...
But stress (I suppose) is reduced when the vessel's surface is thicker.For an sphere, we have Volume: 4/3Pir^3; Area: 4Pir^2 ; Pressure = NRT/V -> So, if we double the radius, we have 8 times volume, having also 8 times the mass we had before (am I right here?)-> But we increase the vessel's area only four times -> This means (I still suppose) that we can have a thicker surface by using, for instance, six times the mass we had before  - And then the stress factor would be higher... -> And Thus couldn't the assertion to non-scalabity be wrong, given that, in my example, we could have a gain in the vessel's surface weight/mass storage ratio? —Preceding unsigned comment added by Dfv10 (talk • contribs) September 7, 2006 (UTC)
:The equation for stress in a thin-walled pressure vessel in the shape of a sphere is s = pr/t, where s = stress, p = pressure, r = radius, and t = wall thickness.  From that equation, you must double the thickness to hold double the pressure at the same stress level.  The mass of the tank will go up proportionally to the thickness if you keep with the thin-walled assumption.  If the wall thickness is too large for the thin-walled assumption, then the volume will indeed go up proportional to the cube of the increase in wall thickness, however the stress equation is no longer valid, and you must use the non-linear form for thick-walled vessels.  I apologize, but I don't have that formula handy, so I can't be sure how it would scale with thick-walled vessels.  The fact that most pressure vessels are thin-walled would imply that someone figured out already that increasing the wall thickness by a lot is not an efficient way to increase storage capacity.  I'll try to find that equation and verify that. - EndingPop 22:30, 7 September 2006 (UTC)
thread_title:  Question regarding scalability 

message: I may have posted this before, but I'll do it again.  I think this page should have the equations for stress in thin-walled pressure vessels.  I would do it, but the equations are kind of difficult to understand without pictures.  Does anyone know where I could find pictures suitable for Wikipedia like the ones at this page?
:I added the equations, though the page may need some formatting that I'm not sure how to do.  I still needs the pictures, but at least people who know what these are already can find them. - EndingPop 00:22, 8 September 2006 (UTC)
thread_title:  Stress in pressure vessel 

message: Cylindrical tanks have twice the wall thickness for the same radius as a spherical tank; but they have more volume. The article thus greatly overstates the advantage of spherical over cylindrical tankage.WolfKeeper 01:29, 8 September 2006 (UTC)
replies: text: I'm really not sure what you're saying here. Wall thickness is independent of radius.EndingPop 01:05, 20 September 2006 (UTC)
replies: text: Careful here. In the equation the stress (sic) is proportional to radius in the equation... Look at it a different way, the surface area goes up proportional to the square of the radius, whereas the volume goes up as a cube. For the tank contents/mass ratio to be constant the wall thickness must be proportional to radius too.WolfKeeper 14:19, 20 September 2006 (UTC)
replies: text: Careful indeed.  I don't have a clue what you're trying to say.  While I agree that the article's final paragraph on scalability is outright wrong (and I'll edit it shortly), what you're saying is very ambiguous.  You've got 4 independent variables to mess with on a spherical tank: stress, pressure, radius, and wall thickness.  To be clear, I'm talking exclusively about thin walled pressure vessels.  That means the normal stress is negligible and the difference in radius between the inner and outer walls is negligible (ie. wall volume=4*pi*r^2*t, not to be confused with overall tank volume).  Now that that is cleared up, what do you mean by "For the tank contents/mass ratio to be constant the wall thickness must be proportional to radius too."?  If the tank contents are constant and you increase r then pressure will decrease proportionaly (Ideal gas law), which means the stress will be constant through the increase in r if you also hold the wall thickness constant.  Let me know if this isn't what you're intending to discuss. - EndingPop 01:59, 21 September 2006 (UTC)
replies: text: I made a bad edit and then reverted it regarding that last paragraph.  So now that I've thoroughly confused myself, I'd love for someone to look that section over and fix it.  I feel like something's not quite right, but I can't find it yet. - EndingPop 02:32, 21 September 2006 (UTC)

text: Whatever your point, I think I addressed it above under the section about scalability. - EndingPop 01:05, 20 September 2006 (UTC)
thread_title: Cylindrical versus spherical weights

message: In my opinion there is a basic difference between a gas pressure vessel and a liquid pressure vessel. A hydraulic (oil) cylinder f.i. was (by Lloyds) compared with just a piece of hp pipe, unless the hydraulic oil was backed up by a gas volume under pressure.
Jeff
: I don't understand what you're trying to say here.  A fluid is a fluid is a fluid.  The formulas all apply the same way.  Why are they fundamentally different? - EndingPop 16:00, 7 January 2007 (UTC)
replies: text: According to the online version of Kirk-Othmer Encyclopedia of Chemical Technology, there are two categories of pressure vessels:
*Low pressure – operating from atmospheric to 15 psig pressure (101.4 kPa)
*High pressure – operating above 15 psig pressure (101.4 kPa)
Note that this definition is independent of the vessel contents.ChemE50 (talk) 23:24, 22 March 2010 (UTC)
thread_title:  Definition of pressure vessel

message: This article is very much in need of a section on pressure vessel design pressure and maximum working pressure. There is no discussion of that subject anywhere in Wikipedia that I can find. - mbeychok 21:45, 19 January 2007 (UTC)
replies: text: While I agree that people shouldn't look to Wikipedia as a textbook on pressure vessel design, I feel its real power is as a reference source.  A person who has experience with this but has forgotten a formula or assumption should be able to come here for a refresher. - EndingPop 04:47, 23 January 2007 (UTC)

text: I concur with mbeychok's comment. People who refer to this article are likely to benefit from an explanation of the pressure terminology affecting pressure vessel design and use. I propose that we add the following:
* Operating pressure – the maximum pressure at which the process contained by the vessel will operate, as specified by the process designer;
* Design pressure – the maximum pressure that must be contained by the vessel, and which is used to calculate the minimum wall thickness;
* Maximum allowable working pressure (MAWP) – the maximum pressure that can be contained by the vessel, based on the actual wall thickness; also known as the maximum allowable pressure (MAP).  —Preceding unsigned comment added by ChemE50 (talk • contribs) 22:49, 22 March 2010 (UTC)
thread_title:  Need a section on design pressure and maximum working pressure  

message: Outsiders may use the name pressure vessel for a vessel filled with a fluid under pressure, experts and classification authorities however reserve the word "Pressure vessel" for vessels filled with gas under pressure, liquified gas or fluid with a gas back-up.
This is due to the difference in energy between a vessel filled with fluid and a vessel filled with gas.
I will try to make 2 calculations about 2 vessels with a content of 1000 litres, one filled with a hydraulic oil of 200 bars, the other filled with high pressure air of 200 bars.
AIR
To fill the air vessel with 1000 litres, one has to compress 200 000 litres of air. If we accet that the average pressure is 100 bar, the energy that is necessary to fill the vessel is (200 000* 100) * 100 000/1000 = 2 * 10^9 Nm.
OIL
To fill the first 999.9999 litres, we do not need energy. Oil is compressible approximately 1 % per 100 bar, so after the first 999.999 litres we have to pump 20 litres under pressure. Again I assume an average pressure of 100 bars and the energy to fill the vessel is (20 * 100) * 100 000 / 1000 = 2 * 10^5 NM.
This means that the energy content of the gas containing vessel is 10 000 times the energy of a vessel containing fluid.
This is the reason for the fact that classification authorities have severe rules for pressure vessels (containing gas).
Above calculation may contain a mistake and is for sure not scientific. If somebody can improve the calculations, feel free to do so.
Jeff 13:05, 31 January 2007 (UTC)
replies: text: 1. Both air and oil are fluids.  2. A "liquified gas" is, in fact a liquid.  3. Why does it matter how much energy it takes to pressurize a vessel?  When it comes do to it, the mechanics are the same for any fluid.  4. If you're going to claim that "authorities" reserve the phrase "pressure vessel" for something in particular, please cite a source.  Isn't it just more common to deal with pressurized gas than pressurized liquid?  Why should that matter?  It's no more work to generalize to both liquids and gases. - EndingPop 15:45, 31 January 2007 (UTC)

text: While I don't disagree with you there, when it comes to design of the vessel you use the same formulas, but apply larger factors of safety.  I am fully in favor of making this distinction in the article. - EndingPop 03:46, 1 February 2007 (UTC)
thread_title:  Is a vessel filled with fluid under pressure a pressure vessel? 

message: It seems that a well know dutch vandal known under the name Christoffel K who pretends to be an expert is vandalizing the English article too after doing the same with the dutch article Bierbuik 07:33, 6 February 2007 (UTC)
replies: text: This user is probably a sockpuppet of a dutch user involved by the dutch discussion. Christoffel K 08:37, 6 February 2007 (UTC)
replies: text: Like always Christoffel_K is very 'kind' with his words to other people trying to hide the fact that he has no clue about what he is talking aboutBierbuik 09:31, 6 February 2007 (UTC)

text: Please finally leave your personal attacks. Christoffel K 11:35, 6 February 2007 (UTC)
replies: text: It describes you very well Christoffel, you are the king of 'if you can't beat them with brains, dazzle them with BS' and also the king of edit wars and personal attacks, you need to be monitored closely here by a mod in every move you make to prevent the same thing happening over here.Bierbuik 13:24, 6 February 2007 (UTC)
thread_title:  Watch out 

message: This is a unprofessional sentence. The design and manufacture of a pressure vessel is normally very expensive and is watched carefully by an authority. Inadequately designed pressure vessels do not exist. I do not say that a mistake is not possible or maybe a company tries to fake things, but an inadequately designed pressure vessel is lika an inadequately designed airplane.
Jeff 20:19, 13 February 2007 (UTC)
thread_title:  A vessel that is inadequately designed to handle a high pressure constitutes a very significant safety hazard 

message: I wonder whether it is of interest to write here all these ASME codes. If you start with ASME codes you also have to give the Lloyds, DNV, GL, RINA, BV, Stoomwezen etc etc codes. In principle I have no objection, but the writer of the ASME codes should also give the other codes. It is not fair to leave this to others.
Jeff 18:11, 14 February 2007 (UTC)
thread_title:  ASME codes etc 

message: I have a link to a worked example on www.excelcalcs.com (I think someone has since decide to remove the link from the page) - but one of my users made the following observation which I am inclined to agree with. The article states that "the hoop stress, or stress in the radial direction" - hoop stresses follow the circumferential direction not the radial direction. Do we need to update the text? BoJosley 08:33, 17 July 2007 (UTC)
replies: text: Fixed the radial --> circumferential. Since I wrote that section, I'm pretty sure I'm the one who messed it up. Thanks for the head's up! Regarding the link to ExcelCalcs, I removed the link. My main reasoning for doing so was that I had seen a number of links to this website be added to mechanics articles, and it seemed that someone with a vested interest in the site was adding links. This seems like site promotion and furthermore the site requires registration to access the files(#3 and #6 in External links - Links normally to be avoided) - EndingPop 15:15, 17 July 2007 (UTC)

text: Notability is a requirement for the wikipedia to use an information source as a reference, or to include a link. Do you have any evidence that your site is notable?WolfKeeper 05:05, 19 July 2007 (UTC)

text: Who are you trying to kid? You're obviously not notable, so why should the wikipedia help you in your SEO? Forgetaboutit.WolfKeeper 18:32, 26 July 2007 (UTC)
thread_title:  Hoop stress / stress in radial direction 

message: 1 open end
2 close end
3 thin shell
4 thick shell  —Preceding unsigned comment added by 203.82.53.154 (talk) 06:13, 4 December 2007 (UTC)
thread_title:  types of pressure vessel 

message: Not that it's a big deal or anything but whenever I'm dealing with pressure vessels and the stresses within I almost always work with diameters. The reason being is that it's rather difficult to measure a radius directly so most drawings/specifications/books/etc would use or find more useful the diameter version of the stress equations ie
:hoop stress = pd / 2t
would this not be more appropriate to have on the page? An alternative of course is doing away with it and just linking to the 'cylinder stresses' page
Sam Lacey (talk) 03:10, 11 January 2009 (UTC)
replies: text: These formulas are derived from first principles.  From what I've seen, radius is usually used; both at efunda, and at the MIT Lecture pdf (linked to from the article under "notes").  The designs and drawings are a result of the theory, not the other way around.  So in the designs and drawings it makes more sense to just set d=2r (assuming a circular cross-section), rather than back-annotate the drawing parameters all the way to first principles; because in the general case, a pressure vessel is not necessarily circular or symmetrical, so the parameter that we want for the derivation is really the radius of curvature, not the diameter. Mikiemike (talk) 15:37, 11 January 2009 (UTC)
thread_title:  Stress equations 

message: I was reviewing my Strength of Materials textbook from my college days and in the section on Pressure Vessels it showed free body diagrams of the interiors of a sphere and a cylinder. It showed principal stresses for hoop (circumferential) and axial (longitudinal) directions but then stated that the shear stress would be zero. I don't get it, I know that there is no angular deformation of a pressure vessel in equilibrium but it still seems like there should be shear stress as a result of axial pressure on infinitesimal volumes. Has anyone got any wisdom on this quandary?JeepAssembler (talk) 22:06, 6 February 2010 (UTC)
replies: text: Post your query in www.eng-tips.com and you'll get a response. Bernoullies (talk) 13:20, 25 November 2011 (UTC)
thread_title:  Shear Stress? 

message: boiler is a type of pressure vessels that made of 17MN-4 steel that can protect from fire up to 2000 degree. and the shell in boiler must be ST37.8 .but it's better to say fire tube boiler is a type of pressure vessel. becuase water tube boiler built in a diffrent design , material and shape.  — Preceding unsigned comment added by 2.144.86.201 (talk) 10:12, 27 June 2011 (UTC)
replies: text: In principle shell steamboilers are pressure vessels. Technically they are treated separately because they are designed and manufactured using different codes and standards (ASME I, ASME IV, EN 12953). Steam boilers, unfired pressure vessels and pressure piping belong to the general category of pressure equipment. SV1XV (talk) 17:47, 28 September 2013 (UTC)
thread_title:  boiler is a type of pressure vessel 

message: The equations refer to W as width of the vessel, but I believe it must be the length, because traditionally the cylinder volume is stated as Base Area X Height. To avoid confusion a simple drawing could be added or a note to clarify it.
Something like: 
: "Consider a cylinder of base S and height H with a semi-sphere in each end. The length of the vessel will be R + H + R..."
I have no rights to add figures yet, so...
All this, if I am right, of course!
Thank you. Hebert Peró (talk) 22:45, 10 June 2014 (UTC)
thread_title:  Cylindrical vessel with hemispherical ends 

message: Fired is often described as a pressure vessel subject to an internal or external heat source. While unfired describes the absence of a gas, oil or coal burner. 
Is an electrically heated pressure vessel fired or unfired?  64.47.214.68 (talk) 09:52, 23 February 2017 (UTC)
thread_title:  Fired vs unfired 

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thread_title:  External links modified 

message: So why was this image removed? No one discussed anything on TALK.  — Preceding unsigned comment added by 101.178.163.19 (talk) 03:46, 19 February 2018 (UTC)
replies: text: According to notes on WikiCommons, it was a copyright violation. --‖ Ebyabe talk - Opposites Attract ‖ 08:54, 19 February 2018 (UTC)
thread_title:  Expansion_vessel_25_lts.png 

message: The cylinder here is a cut length of large diameter (36 in Nominal Pipe Size?) pipe of a suitable grade of steel. The ends are machined to suit. Peter Horn User talk 16:35, 21 August 2019 (UTC)
replies: text: But the real point is that in the simplified maths of most pressure vessel design, a shape like this is a "cylinder" (and has end caps) but a "pipe" is considered as infinitely long, thus the end effects are ignored. To design this vessel, you'll have to think about is as being short, fat and with the end effects needing to be calculated. Andy Dingley (talk) 16:40, 21 August 2019 (UTC)
thread_title:  Cylinder vs pipe