Talk:Pressure vessel

Gage vs. Gauge
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)


 * 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)


 * 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)


 * 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)

Formulas for thin-walled pressure vessels
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)

Boiler is a generic term for many different items
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)

Need better image
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)
 * 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)


 * i placed a request on request images, nothing on commons. Mion 22:07, 3 August 2006 (UTC)


 * I am about to upload a new image ... see what you think of it Exit2DOS2000   •T•C•  01:10, 12 July 2007 (UTC)

Very little relevance to ball valve, check valves, pressure gauges, etc.
As one who spent 50+ years in the engineering design, construction and operation of petroelum refineries, chemical plants, natural gas processing plants and power plants, I fail to see the relevance in the Wiki links to ball valves, check valves, flashback arrestors, pressure gauges or manometers. This is an article about pressure vessels ... it is not about all the various types of valves or pressure measurement devices or any other equipment present in industrial plants. I agree that relief valves and/or safety valves are relevant. I am accordingly deleting the irrelevant links. - mbeychok 16:14, 4 August 2006 (UTC)


 * Yes you worked on big plants with central measuring, however these links are about small home solutions like LPG pressure vessels and there you will see always pressure gauges or manometers, etc on the vessels. reg. Mion 18:01, 4 August 2006 (UTC)


 * Who said this article was about "small home solutions"? Did you make that unilateral decision for all the rest of us? In any event, pressure gauges, manometers, valves, and so forth are usually installed in the associated piping.  In those cases where such items might be attached to a pressure vessel, they are still not relevant to explaining what a pressure vessel is or how they are  designed or how they are used. Pressure vessels are also often painted and insulated ... but that doesn't mean that a link to paint or to insulation is relevant or warranted. - mbeychok 18:30, 4 August 2006 (UTC)

I am going to make this also about small home solutions, and in the text there is a section about pressure in the vessel right ? now how are we going to measure that ? the fact that there is 10 cm of pipe in between doesn't matter, reg.Mion 20:26, 4 August 2006 (UTC)

Well, maybe i said it wrong as you are the one with the expertise. In this article we are missing a section about from which materials are pressure vessels made. ? which types of vessel can be used to store hydrogen ? reg. Mion 20:44, 4 August 2006 (UTC)


 * Mion, the only type of pressure vessel I can think of as being prsent in "small homes" would be an LPG tank (meaning Liquified Petroleum Gas) used for cooking or perhaps for heating. LPG is a mixture predominantly of propane, isobutane and normal butane. The exact percentage of each of those components varies quite a bit from one manufacturer to another. The pressure required to store liquid propane at a typical ambient temperature of 20 °C is about 8 bar. The pressure to store liquid normal butane at 20 °C is 2 bar. Thus, the pressure required to store store LPG at that temperature may range from 2 bar up to 8 bar, depending on the manufacturer. At those storage pressures, it is ridiculous to even think of using manometers to measure the pressure inside a pressure vessel.


 * As for storing liquid hydrogen at 20 °C, the required pressure would be extremely high unless the storage tank is maintained at extremely low cryogenic temperatures. There are some tanks available for storing compressed hydrogen gas at pressures of 350 to 700 bar.


 * As for materials, pressure vessels can be constructed of various metals depending upon the storage pressure and temperature as well as what is being stored. Obviously, storing corrosive acids would require different materials than storing propane.


 * Mion, please don't take this personally ... this article still needs a great deal of information, but that information should be provided by experts in the subject. It is not a subject that can written by someone who is completely unfamiliar with the subject. And it is not subject that can be made into a "small home solution".


 * As a chemical engineer myself, I know just enough about this subject to realize that this article needs to be worked on by an experienced mechanical engineer. - mbeychok 23:16, 4 August 2006 (UTC)

I didn't mean high pressure storage of hydrogen but medium storage like in this article [] as you can see there is a ball valve attached for testing, and a measure device. By adding a section about this type of hydrogen storage i think we can get a nice full worked out example of usage and parameters of a pressure vessel. reg. Mion 11:22, 5 August 2006 (UTC)


 * Mion, the article you referred to was written by Mr. Pyle in 1997. I don't know where you live but I live in the United States and, even though it has been 9 years since that article was written, I have yet to hear of anywhere where I can buy or install in my home any cylinders filled with metal hydride for storing hydrogen.


 * The use of hydrides for storing hydrogen has been studied and talked about for the last 20 years or so ... but commercialization of the technology is still a long way from realization.


 * I regularly use LPG storage cylinders for my barbeque grill. Do you have any idea how many governmental and other design codes exist to protect you and I from poorly designed LPG containers? None of that required design code infrastructure exists anywhere as yet for storing hydrogen in small containers for home use.


 * In any event, Mr. Pyle's type of "home solution" (to use your term) has nothing the do with an article about the hundreds of thousands of pressure vessels already in existence worldwide in commercial establishments and in industrial plants (such as oil refineries, petrochemical plants, power plants, etc) ... and which are covered by a multitude of pressure vessel design codes in almost every country in the world. As I said before, this pressure vessel article still needs to be expanded to include more relevant information. But, in my opinion, it does not need expanding to include a section on the the use of hydrogen in a home power system which would be completely irrelevant to an article on pressure vessels.


 * The use of metal hydride storage containers for home use (or for automotive use) is an entirely different subject from that of this article about pressure vessels. If you want to include such information in the Wikipedia, the best way of doing so is to write a new article devoted to that subject. You might entitle it "Home Power Systems Using Hydrogen".


 * Just a few more items about Mr. Pyle's article:


 * I could not find any mention of a "ball valve" anywhere in the PDF article, even though I used the PDF Find function. That really isn't relevant anyhow.
 * The article did include a small flow schematic that clearly showed that the associated piping included valves of some type, pressure regulators, pressure gauges, a vacuum gauge and a flowmeter. But they really have nothing to do with the design of of the storage cylinders ... they are totally about how to regulate the flow and pressure of the hydrogen withdrawn for use.
 * The article included a chart showing the flammable range of hydrogen to be from 18 to 59 volume % in air ... as compared to 6-14 volume percent for methane (natural gas) and 2 to 10 volume percent for propane. Actually, the flammable range of hydrogen is from 4 to 74 volume % in air, per the "Handbook of Chemistry and Physics", 6th Edition, page D-106, CRC Press. Be that as it may, hydrogen is by far more more flammable, and hence more dangerous, than almost any other gas. If you do write a new article on the home use of hydrogen, you should be sure to stress how dangerous it is to handle hydrogen.
 * - mbeychok 18:08, 5 August 2006 (UTC)

The ball valve is on the photo, anyway, yes hydrogen is more flammable, the thing is, not if you dont ignite it, than nothing happens, and in a outside open placement it doesn't collect on the ground but will go up, which makes it safer than gasoline., and there are more sides on it, one of them is small leakage, and the main question about these propane vessels in the article, will they start to corrode ? . reg. Mion 00:11, 6 August 2006 (UTC)


 * If you can recognise the type of valve in the photo, you must have x-ray vision or extrasensory preception (ESP), not that the valve type has any relevancy to our discussion. Do you have any idea at all as to how many industrial facilites have suffered major explosions, fires and damage and worker fatalities resulting from the use of hydrogen despite spending million of dollars to avoid ignition of the hydrogen?? There have been many such incidents. And you think that the average homeowner will be able to handle hydrogen safely??


 * Mion, let me repeat that you should write a new article, "Home Power Systems Using Hydrogen". Without any intent to offend you, I will no longer continue this debate with you, because it is very difficult to debate with someone who has simply read some magazine articles on home power units and has so little technical knowledge about the subject. Again, I urge you to start a new article on home power systems and I promise you that I will not hinder you in any way. If you have never started or written a new Wikipedia article and need some help in doing so, I would be happy to help you.- mbeychok 00:35, 6 August 2006 (UTC)

I did, sort of, Hydrogen station, and the only wy to prevent people from making mistakes is to extensivly describe the ins and outs of each part in the hydrogen system including the risks involved or the advantage if you would do it as described, if i have a look at the wiki articles, there is almost no information at all about the different parts. leaving out the information is much more dangereaus than adding it proper. reg. Mion 00:55, 6 August 2006 (UTC)

Who is able to inform me how a checkvalve (non return valve) is related to a pressure vessel. I personally do not know one pressure vessel with a check valve mounte upon it. Reliefvalve yes, ball valve yes, pressure gauge, yes, but check valve :no.

Jeff 16:36, 29 January 2007 (UTC)

PD 5500
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)

in Color ?
yes, there is a better one: Image:Dampfkessel für eine Stationärdampfmaschine im Textilmuseum Bocholt.jpg on commons. -;) Mion 20:41, 29 August 2006 (UTC)


 * Mion, I think the image you found is about the same as the one that is now in the article. Both are quite ancient and both have riveted seams. The one you found is completely rusted and has torn insulation on the top nozzle.


 * What I was hoping for was a new vessel with welded seam construction (instead of rivets) and freshly painted. Could you perhaps locate one like that? - mbeychok 07:33, 30 August 2006 (UTC)


 * We are progressing from a black and white photo to a coloured foto !! and for the new one it seems we have to make them our selves, it has to wait a bit, its raining now. reg. Mion 07:02, 30 August 2006 (UTC)

Question regarding scalability
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)

Stress in pressure vessel
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)

Cylindrical versus spherical weights
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)
 * I'm really not sure what you're saying here. Wall thickness is independent of radius.EndingPop 01:05, 20 September 2006 (UTC)


 * 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)


 * 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)
 * 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)


 * Whatever your point, I think I addressed it above under the section about scalability. - EndingPop 01:05, 20 September 2006 (UTC)

Definition of pressure vessel
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)

It is simple. A pressurised container with oil or water is less dangerous than such a container with a pressurised gas, this because of the fact that the energy content of the gas is much more. In fact if a "couple"of drips of oil leak from the vessel, the pressure has gone, whereas with gas this takes some time. For these reasons, the classification authorities make a difference with oil and gas content. Testing of a gas container is therefor always done with water or oil. I think the definition of pressure vessel that is used by classification authorities exclude a fluid, unless it is pressurised by a gas.

Jamclaassen 19:07, 22 January 2007 (UTC)

Again I would state that a "container" is only called "pressure vessel" if the content is a gas or a liquified gas or a fluid with a back-up gas volume. A container with hydraulic fluid under pressure would therefor not be a "pressure vessel". Anyway this is a definition I found in a "technical encyclopedia". Classification authorities call a (gas) container only a pressure vessel if pressure x volume is above a certain value. Hydraulic cylinders were not regarded as pressure vessels by Lloyds say 20 years ago; they were regarded as a high pressure pipe. Jamclaassen 09:19, 25 January 2007 (UTC)


 * According to the online version of Kirk-Othmer Encyclopedia of Chemical Technology, there are two categories of pressure vessels:

Note that this definition is independent of the vessel contents.ChemE50 (talk) 23:24, 22 March 2010 (UTC)
 * Low pressure – operating from atmospheric to 15 psig pressure (101.4 kPa)
 * High pressure – operating above 15 psig pressure (101.4 kPa)

Need a section on design pressure and maximum working pressure
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)

I do not think you can use Wikipedia for designing pressure vessels. Somebody who design pressure vessels will never look in Wikipedia how to do it. The different classification authorities have different ways to design a pressure vessel. Following pressures are important: Design Pressure, Test Pressure, "collapse" pressure. Some authorities specify factors, some additional pressure, some a combination of both. Choice of material is very important, especially if the vessel has to be outside on a ship.

Jamclaassen 19:13, 22 January 2007 (UTC)


 * 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)

As I told before, each classification authority uses criteria. Not for the calculation of the stress, but for the acceptable stresses for design pressure, test pressure, collapse pressure etc. Every mechanical engineer can derive that the stress in a cylinder is pressure x diameter (x length)/(2 x wallthickness (x length)) I donot think it is important to write this in the article, because the choice of materials and the stress in the sphere part are much more interesting matters. Jamclaassen 09:10, 25 January 2007 (UTC)


 * 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)

Is a vessel filled with fluid under pressure a pressure vessel?
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)


 * 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)

Look in the rules of Lloyds, ABS, DNV, RINA, GL, Stoomwezen. Because of the fact that a vessel containing gas, liquified gas or a fluid backed up by gas is say 10000 times more dangerous than a vessel just filled with hp oil or water. It is not me who stated this, it is not even the classification authorities, but all national laws in all countries in the world. Technical encyclopedies (mine is Winkler Prins) also state this. Laws about pressure vessels are as old as the steam engine, because steam, being a gas is very dangerous compared to fluid. Pressure containers with just a fluid do not give an explosion; vessels with gas (LPG, fluid backed up by a gas) give an explosion if something goes wrong. It is like the difference between an (toy)airgun and a real gun; for you, they are the same. Sorry that you do not understand this. People who know about pressure vessels however will understand my contribution. Jeff 20:11, 31 January 2007 (UTC)
 * 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)

I have seen that the article was changed, now again the definition of pressure vessel is including fluid. When I worked with pressure vessels, a vessel with fluid under pressure was not a pressure vessel; the reason will be given here. As the European committee gives the name pressure vessel to all pressure containing things I understand. According to the definition I think also tennisballs are pressure vessels. On the other hand I think that if I would change the article this must be rechanged every week. So i propose to make the defintion somewhat as is it written now. Subsequently we could write that there is a european definition but this is a very vague thing. Subsequently we can introduce the PED Category, where you can see whether your pressure vessel is in category 1 to 4. This PED searcher can be downloaded from the Dutch Lloyd's site. In this searcher you have to fill in: Pressure vessel or piping ,fluid or gas or dangerous fluid or gas, pressure and volume. If you do so than you can see that pressure vessels with just hp fluid even if the volume is 500 liters and the pressure is 500 bar can be designed for "good workmanship". No rules are applicable and no tests are needed. Maybe we can make the difference Pressure vessel acc code and pressure vessel without code or something like that. Jeff 18:37, 14 February 2007 (UTC)

Watch out
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)
 * This user is probably a sockpuppet of a dutch user involved by the dutch discussion. Christoffel K 08:37, 6 February 2007 (UTC)
 * 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)

C is amongst others the writer of the following contributions to the dutch Wikipedia: "wedding" "hood" "daily life" "quilt" "showergel" "guest" "greengrocer" "dexterity" "swimming suit" and a dozen of other "most valuable" contributions. He claims that he is a graduated engineer but he mounts explosionhedges (used in walls of saw-mills) on pressure vessels as well as breath masks!!He writes that it is impossible to make diving (breathe) tanks and LPG containers out of alluminium. But the worst, he will continuous suck and suck and suck until the opponent stops answering, so that he can say that he is the winner. The Dutch article is blocked and therefor C is now violating the English article. Jeff 10:25, 6 February 2007 (UTC)
 * Please finally leave your personal attacks. Christoffel K 11:35, 6 February 2007 (UTC)
 * 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)

A vessel that is inadequately designed to handle a high pressure constitutes a very significant safety hazard
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)

I think the sentence is valid. Yes there are inspectors that oversee calculations and along with QC that oversee the construction, NDE and hydrotest also insure integrity but if these people make a mistake or are misled (or the calculations are improperly applied or equated) then the vessel could be made unsafe. You can find examples of vessels failing every year, with great damage and loss of life. It is true that vessels designed to high pressure CAN represent a danger (particularly if they hold a gas), as a failure would result in an explosion (with or without fire) as a great amount of energy is released in a small amount of time, its essentially a bomb at high pressure, thus they can be extremely dangerous. FYI planes crash due to design failures as well. Yes the danger can be mitigated, but it remains nonetheless. — Preceding unsigned comment added by 70.167.45.242 (talk) 21:32, 7 April 2014 (UTC)

ASME codes etc
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)

are boilers and pressure vessels the same?
dear sir/madam, I WOULD LIKE TO KNOW IF BOILERS AND PRESSURE VESSELS THE SAME? AND WHAT PURPOSE ARE THE PRESSURE VESSELS USED FOR?

Hoop stress / stress in radial direction
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)

Secondly regarding the removal of the www.excelcalcs.com link - our mission statement is "ExcelCalcs will build the web's largest repository of solved problems using the world's most popular mathematical software tool (Excel) and make it available to the world for free" it is a noble cause and I believe that links to it from wikipedia are valid and useful to wikipedia users. Would you reconsider reinstating the link? BoJosley 08:59, 17 July 2007 (UTC)


 * 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)

I am the administrator of the excelcalcs website, I say this to declare my interest, and also to admit that I have been placing external links to the site from wikipedia because I thought that links to a repository of related solved problems would be of interest to wikipedia readers. Please note that ExcelCalcs requires registration but registration is free. Would you reconsider reinstating the link?BoJosley 22:13, 18 July 2007 (UTC)


 * 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)

I launched the site in March 2007 I have given away 13265 downloads for free and I have many user testimonials on the site forum http://www.excelcalcs.com/component/option,com_fireboard/Itemid,145/func,view/id,33/catid,11/ BoJosley 21:49, 19 July 2007 (UTC)

The ExcelCalcs site requires registration to ensure that visitors do not disrupt the forum discussions with undesirable topics (prior to registration we had a number of posts for Russian brides).This is no different to your own policy of logging in to wikipedia to make contributions. I would be delighted if you allowed my links and I believe that it is an enhancement to the page.BoJosley 18:00, 26 July 2007 (UTC)


 * 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)

Disappointed - at least we made the correction to the page which started this thread. Following your comments I have removed the requirement to register before downloading from www.excelcalcs.com. I'll carry on building the site and hope one day it is considered 'notable'.BoJosley 14:20, 9 November 2007 (UTC)

What is the role of temperature in pressure vessel when fluid or any chemical in vessel is rotating....?
dear sir/madom.... i would like to know abt the role of temperature in a presser vessel when a fluid or any chemical is rotating in vessel.....?

types of pressure vessel
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)

Stress equations
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)
 * 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)

Shear Stress?
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)JeepAssemblerJeepAssembler (talk) 22:06, 6 February 2010 (UTC)
 * Post your query in www.eng-tips.com and you'll get a response. Bernoullies (talk) 13:20, 25 November 2011 (UTC)

boiler is a type of pressure vessel
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)


 * 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)

Cylindrical vessel with hemispherical ends
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)

Fired vs unfired
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) — Preceding unsigned comment added by 64.47.214.68 (talk) 09:47, 23 February 2017 (UTC)

External links modified
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Expansion_vessel_25_lts.png
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)
 * According to notes on WikiCommons, it was a copyright violation. -- ‖ Ebyabe talk - Opposites Attract  ‖ 08:54, 19 February 2018 (UTC)

Cylinder vs pipe


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) 
 * First of all, how do we know this? Also it's a pretty rare situation (oil, gas and water pipelines) to describe anything "36 in diameter" as "pipe". In most industries, even pretty heavy industries, this would have been rolled at this size.
 * 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)

ːː See NPS 26 to NPS 36 and Additional sizes (NPS). In this case 36 inches is a visual estimate as would be 6 ft 0 in long. So the design drawing as well as the shop drawing would call for a pipe 36" OD x 6'-0" long x $7/16$" wall. I know this because, apart from working for MLW, I also worked for consulting engineers and fabrication shops as a drafter. Peter Horn User talk 21:20, 21 August 2019 (UTC)