What is Pressure vessel: Definition and 93 Discussions

A pressure vessel is a container designed to hold gases or liquids at a pressure substantially different from the ambient pressure.
Construction methods and materials may be chosen to suit the application, and will depend on the size of the vessel, the contents, working pressure, mass constraints, and the number of items required.
Pressure vessels can be dangerous, and fatal accidents have occurred in the history of their development and operation. Consequently, pressure vessel design, manufacture, and operation are regulated by engineering authorities backed by legislation. For these reasons, the definition of a pressure vessel varies from country to country.
Design involves parameters such as maximum safe operating pressure and temperature, safety factor, corrosion allowance and minimum design temperature (for brittle fracture). Construction is tested using nondestructive testing, such as ultrasonic testing, radiography, and pressure tests. Hydrostatic pressure tests usually use water, but pneumatic tests use air or another gas. Hydrostatic testing is preferred, because it is a safer method, as much less energy is released if a fracture occurs during the test (water does not greatly increase its volume when rapid depressurization occurs, unlike gases, which expand explosively). Mass or batch production products will often have a representative sample tested to destruction in controlled conditions for quality assurance. Pressure relief devices may be fitted if the overall safety of the system is sufficiently enhanced.
In most countries, vessels over a certain size and pressure must be built to a formal code. In the United States that code is the ASME Boiler and Pressure Vessel Code (BPVC). In Europe the code is the Pressure Equipment Directive. Information on this page is mostly valid in ASME only. These vessels also require an authorized inspector to sign off on every new vessel constructed and each vessel has a nameplate with pertinent information about the vessel, such as maximum allowable working pressure, maximum temperature, minimum design metal temperature, what company manufactured it, the date, its registration number (through the National Board), and American Society of Mechanical Engineers's official stamp for pressure vessels (U-stamp). The nameplate makes the vessel traceable and officially an ASME Code vessel.
A special application is pressure vessels for human occupancy, for which more stringent safety rules apply.

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  1. Findustry Corp

    Low Viscosity Oil, Tanks, Pressure Relief Valves and Check Valves

    Hi Whoever, I have an idea for a system which would work for my food business but it doesn't exist. The system essentially relies on hydraulics, pressure relief valves and check valves for recirculation upon reached pressure. All tanks/pipes (The entire system) will be prefilled except for 1...
  2. T

    Cubical Pressure Vessel - Maximum Pressure Computation

    Hello everyone - this is my first post on the forum and this would be for a real world application. I have no mechanical engineering experience. We plan to build a cubical aluminium (6082 grade) pressure vessel. The total external dimensions are 540mm x 400mm x 75mm. The aluminium wall...
  3. L

    Pressure vessel wall thickness ASME BPVC VIII vs AS1210

    The ASME BPVC formula is t=PR/(SE-0.6P) where P = pressure , R = inside radius, S = allowed material design stress and E = joint efficiency factor. the AS1210 formula ,(equivalent nomenclature) is t=PR/(SE-P). This makes 1210 more conservative when using the inside radius . I suspect the pure...
  4. FEAnalyst

    Stress in rectangular vessel subjected to hydrostatic pressure

    Hi, it's not easy to find formulas for stress in rectangular pressure vessels. However, I've found some in a Polish book titled "Podstawy konstrukcji aparatury chemicznej" (Fundamentals of the design of chemical process equipment) by J. Pikon. The problem is that the book provides equations for...
  5. G

    Choosing a Flexible hose for outlet air pressure vessel

    Hi everyone, What should be the considerations to choose the proper hose (max working press) installed at outlet air pressure vessels (11 bar) for industrial purposes? Please remark source\link. Also, I've found a table which lists the max sys operating press for 4 different fluids (fuel, oil...
  6. B

    Find hole size for allowable leak in pressure vessel

    Hello, all. I am completely new here so please be gentle. I have a small, cylindrical, sealed ("no leak") pressure vessel with an approximate volume of 27 cm3. It has a constant supply of air pressure at 8"WC. I'm trying to figure out how big of a hole it can have if there is an allowable...
  7. Zahid Iftikhar

    Time of Impact of Gas Molecules on the Inner Wall of a Pressure Vessel

    In derivation of relation for pressure of Gas ,(see pic below) the time for rate of change of momentum of molecules should be the time for which the wall of the vessel and the molecules kept interacting with each other, not the time between successive collisions. As circumscribed below, my...
  8. G

    Pressure vessel thickness U.S. measurement

    Hi everyone, In purpose to estimate the corrosion degredation in pressure vessels it is recommended to measure the pressure vessel thickness using an U.S. device. My question is how to determine the number of test points on the shell/caps surface as a function of the pressure vessel size...
  9. G

    Eliminating Air Bubbles in a pressure vessel under testing

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  10. FEAnalyst

    Capped pressure vessel - strength and stability

    Hi, in mechanics of materials books one may easily find fomulas for stress and strain in thin- and thick-walled cylindrical pressure vessels subjected to internal pressure. However, it is assumed that they are open. So what are the formulas for stress and strain in capped vessels (with flat or...
  11. S

    ASME compliance in Pressure Vessel design

    Summary:: Hello i have a question regarding pressure vessel design. As per the required operating parameters for a pressure vessel, i have calculated the sheet thickness for the shell to be 4 mm and base plate thickness to be 25mm. These results are based on ASME calculations and ansys.Both...
  12. carveranderson

    Pressure vessel made with a metal tube and a clear polycarbonate lid

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  13. C

    Calculate Pressure vessel Collapse Pressure

    Homework Statement I have a simple cylindrical pressure vessel with thickness 100m and inner radius 254mm,.the cylnder has flat head closed ends but these are thickness 30mm. I need to calculate the pressure that would cause the vessel to collapse given material properties E=207Gpa, poissons...
  14. B

    Speed of a cap when released from a pressure vessel

    Hi, Pressure vessels have caps on top of them. These caps are secured with tri clamps and if you need to remove them you have to make sure that the tank's pressure is released. If the tank is under pressure (say 10psi) and an operator removes the cap (A is known), what is the speed of the cap?
  15. V

    Calculation of pressure variation due to fluid discharge

    Dear all, I have a headache and I need you help, with the following problem. I need to create excel sheet for the calculation (estimate) of the size of the orifice on the orifice plate that will produce a pressure reduction rate in pipeline at 0,5 bar per minute. It is not important to...
  16. A

    Discharge of a Pressure Vessel Containing Liquid Nitrous Oxide

    Homework Statement I want to design a closed tank with an orifice hole (that can be opened and closed remotely) at the bottom of the tank and model how the mass flow rate of liquid nitrous oxide changes with respect to time, as the liquid nitrous oxide leaves the tank due to a pressure...
  17. Jschrodes4

    Single Cycle Pressure Test for Pressure Vessel

    Homework Statement I need to design a pressure test that, in one cycle, will simulate the 8000 cycles that a given pressure vessel will undergo. I know the dimensions and material of the vessel, the number of pressure cycles it will undergo, and the max and min working pressures. Homework...
  18. H

    Thick walled Pressure vessel -Principle stresses

    Homework Statement Hi, I trying to calculate principle stresses for pressure vessel (thick walled) which is pressurized from inside. I calculated all 3 stresses radial, hoop and axial and looking for what formulae to use to get to principle stresses. thanks Homework EquationsThe Attempt at a...
  19. IAMJackal

    Analysis of DE Pool Filter as Steam Pressure Vessel

    Have built a 55 gallon DIY steamer from a DE pool filter. The pool filter is made from .06 inch stainless steel and was rated for an operating pressure of 50 PSI. As a pool filter, the vessel regularly operated at pressures of 10-15 PSI, and as much as 25-30 PSI when it needed cleaning. Have...
  20. R

    B Pressure Vessel Length Contraction and Pressure Comparison in a Spaceship

    I have 2 identical pressure vessels P1 and P2, exactly 1000 cc each. I pressurise them both to exactly ##1000 lbs/in ^2##. I place one on a spaceship and keep the other beside me. The ship blasts off. As the ship whizzes past me, as a result of length contraction, I see that the vessel on the...
  21. Prizzard

    I Crazy steam-hydraulic unit design

    I can't find equations for wall thickness or required temperature to generate steam at 6000psi. The goal here is a pressure vessel 'cylinder' 30" diameter, 36" long. It will be used to pump 42000psi hydraulics using a piston pump directly driven to a smaller series of pistons to allow the...
  22. M

    Computation of maximum pressure in heated closed vessel

    I have a relatively simple design problem but my memories of thermodynamics are very rusty and I can't figure it out on my own. To make it short, I want to put a mix of solid, water and air in a 500mL pressure vessel and heat it all up to 250'C for several weeks. T and P are at room conditions...
  23. Ketav

    Calculus: Verify Thick Walled Cylinder Equations

    Homework Statement I have a system of two ordinary differential equations as shown below. I have to prove that the Lame's exact solutions for a thick walled cylinder loaded by internal pressure satisfies the equations. The next step is to integrate the equations to obtain an equation for U...
  24. A

    Air Tank Discharging Through A Nozzle - Unsteady Flow

    Hey, So I have a system where there is an air tank (0.2Litres @ 3000psi, 293K) and I have a convergent-divergent nozzle attached directly to it. What I want to know is an expression for how the mass flow rate varies with time as the mass in the tank decreases causing the pressure to decrease...
  25. K

    Thin-walled pressure vessel, hoop stress Question

    http://www.efunda.com/formulae/solid_mechanics/mat_mechanics/pressure_vessel.cfmaccording to the text above, we assume that force acting on the thin wall is p*2pi*r^2 whcih is the internal area of vertical slice. But I am not sure why the area has to be 2*pi*r^2. I mean, why pressure on the...
  26. A

    How can I calculate flow rate for leaking pressure vessel during maintenance?

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  27. serenahalterman

    Pressure Vessel Design Question

    Hello, I am replacing an existing ASME Section VIII Division 1 column. The U-1 states it is designed to 240psig @ 650degF, but does not say anything about being designed for vacuum conditions. The SIS for the column states that it is safe to operate under full vacuum. The SIS is not a code...
  28. O

    Need Help With Thin Walled Pressure Vessel Problem

    Homework Statement My professor has given us the solutions to the problem, but I am having a hard time decoding what exactly is going on from the solutions, especially in parts B and C. For Part B: I understand where the numbers are coming from and that this is a force balance problem...
  29. A

    200,000 psi Hydraulic pressure vessel wall thickness?

    I'm Having a part machined with a cylinder shape approximately 14 inches in length with a cylinder hole in the center with a diameter of .930 . I have no idea how thick the cylinder wall needs to be. I have looked up and used hoop stress calculators online but I do not understand if they take...
  30. B

    How do I design a pressure vessel with given data?

    I have been asked to design a pressure vessel and the data given to me for the problem is - content -oil of density 0.9 g/ cm3. material with ultimate tensile strength of 70,000 psi. factor of safety 3. volume 50 m3. How do I calculate the internal pressure and diameter, which I will need to...
  31. M

    What is the Relationship Between Radius and Pressure in a Pressure Vessel?

    Homework Statement The problem is to calculate the required thickness of the shell of a pressure vessel, given that the design pressure P is 400 psi, the strength S is 15800 psi, the corrosion allowance CA is 1/8"and ##R_{design}## is to be found by iteration. Homework Equations...
  32. L

    Pressure Vessels: Internal & External Pressure Effects

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  33. F

    Calculating pressure drop from a pressure vessel leak

    THIS PROBLEM WAS MOVED FROM GENERAL PHYSICS TO THIS FORUM BECAUSE OF ITS HOMEWORK-LIKE NATURE. SO THERE IS NO TEMPLATE. Pressure vessel has a electrical (coiled) furnace inside. A pressure vessel @ 550 bar @ 500 C containing argon has its gas inlet pipe (1 inch ext Diameter) that has come...
  34. D

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  35. D

    What are new ways to open a cylindrical pressure vessel?

    I am currently helping one of my old physics professors and his Phd student designing a pressure vessel for ultra-sciencey detector (still figuring out the theory behind it all). So far we have the general vacuum tank that opens on the ends, with the pressure difference holding the ends on...
  36. K

    Pressure vessel Design - Splay out concern

    Dear Members, The existing design for the pressure vessel is an end cap bolted to the body which is not designed to any pressure vessel code. Currently I'm trying to qualify this pressure vessel to PD5500 code. Due to the derated allowables in the code i couldn't go with the bolted...
  37. T

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    Homework Statement The strength of longitudinal joint in Fig. 1-17 is 33 kips/ft, whereas for the girth is 16 kips/ft. Calculate the maximum diameter of the cylinder tank if the internal pressure is 150 psi. - See more at...
  38. C

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    So there is a mass of 100kg and volume of 1m^3. (Distiller water) That's 0.01 m^3/kg How do I calculate the percentages?
  39. T

    Osmotic Pressure within pressure vessel

    Hi could someone point me in the right direction about the following scenario A high pressure vessel is 100% filled with an incompressible liquid A membrane separates two sides with differing concentrations one (one may be zero) of an impermeable solute. What would occur ? My feeling is that...
  40. S

    Designing an Elastomer Pressure Vessel for Constant Pressure Applications

    Hello Physics Forum. I'm looking to use the vapor pressure of a liquid to apply a constant pressure to a piston. The vapor pressure of the liquid is higher than the pressure I'm looking to exert (vapor pressure is ~16psi and I need to push with a pressure of 5.5psi). I'm thinking of using an...
  41. P

    Pressure vessel ideal gas calculation

    Hello all, As part of a research project, I am trying to calculate the amount of water/dry ice I would need to put in a cylindrical pressure vessel to obtain an internal pressure of ~100 psi at 200C (from room temperature, ~23C). I haven't had to do a calculation like this in awhile, but...
  42. mattyboson12

    Calculating Wall Thickness and Bolt Diameter for a Spherical Pressure Vessel

    A spherical pressure vessel of internal diameter 2m is constructed by bolting together two hemispherical domes with flanges. Assuming that the number of bolts used to join the two hemispheres together is 12, determine the wall thickness of the dome and the diameter of the bolts, if the maximum...
  43. R

    Pressure vessel exploding within an atmospheric chamber

    I am currently investigating pressure test safety with my current employer. Currently we test pressure vessels inside steel test containers, see attached pdf. At the moment Boyles law is used to calculate the resultant pressure increase inside the steel container if the pressure vessel was to...
  44. K

    Designing pressure vessel

    Hi I was wondering how to design the horizontal pressure vessel on twin saddle that is not a symmetric shape using PD 5500 code. For example, Annex G of the code shows how to design with twin saddle, but it is only approach with the symmetric pressure vessel. Anyone has an idea or any...
  45. D

    Mechanics - cylindrical steel pressure vessel

    mechanics -- cylindrical steel pressure vessel Homework Statement A thin-walled, closed-end, cylindrical steel pressure vessel, internal diameter 500 mm and wall-thickness 10 mm, has an internal volume 0.5 cubic metres. Find the additional volume of a compressible fluid that must be pumped in...
  46. R

    Location of Safety Valve on a Pressure vessel

    Is there a specific location (say top, bottom etc.) that a safety relieving valve is put on a pressure vessel? Say there's a tall refining separation column (operating above atmospheric pressure), where would logic (or codes) indicate that a pressure relief valve ought to be ideally placed...
  47. L

    Is the Pressure Vessel Design for a Railway Cistern Appropriate?

    Design a railway cistern for 120,000 kg of Liquid. It has to be a cylindrical shell on two supports. The cistern is 18 m long 3 m in diameter (inner). It is made of steel with the yield strength of SY= 240MPa. Safety factor of FY= 1.9; Total corrosion allowance, c= 3.0 mm; Welded joint...
  48. C

    Curious - question about a pressure vessel and tempreature

    I have no intention of designing, building or experimenting with this, so no worries about safety. I'm just curious and did a Google search for Physics Forums and this was the first to come up. I was wondering, when pressure decreases so does temperature, right? So, were we to have a pop...
  49. E

    Submarine pressure vessel design

    I'm working on the design for a dry-hull model submarine. My plan is to cast the hull shape that I want out of aluminum because this type of casting is cheap, easy to make, and because aluminum has a good strength to weight ratio. I want the hull to be able to withstand an external pressure of...
  50. J

    Pressure Washer Pump used to pressurize pressure vessel?

    Hi, I am working on a project that requires me to pressurize water in a small pressure vessel up to a pressure of 1500 psi. I am searching for a pump to do this. Do you guys think a pressure washer pump such as this one...