Questions tagged [pressure-vessel]

Containers that are designed specifically to retain internal pressure or a vacuum

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2answers
4k views

Why do we neglect the radial stress in case of a thin pressure vessel?

A cylindrical or a spherical pressure vessel, having inner diameter $d$ & thickness of wall $t$, is called thin if $\large \frac{t}{d}<\frac{1}{20}$. $\bullet$ Thin cylindrical pressure ...
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1answer
69 views

Easily compute a good approximation of heat conductivity of cooled semi-vacuum (water vapor + air)

I am preparing a classroom demonstration about heat, including a demo of how a satellite loses heat only radiatively, since it's flying through a vacuum. I'd like to make the vacuum-production ...
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2answers
133 views

How to calculate the pressure loading of a vented silo explosion?

I would like to independently check a vendor's silo design for proper explosion venting. Worst case, it is essentially cylinder filled with a stoichiometric mixture atomized sugar dust and atmospheric ...
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2answers
174 views

Making a radial (only) seal inside a small tube

I'm trying to make a adaptor to fit a nozzle about 5mm wide which only applies pressure radially during insertion. Pushing in a standard O Ring would apply some force axially up or down the inlet due ...
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4answers
3k views

Calculating maximum internal pressure from maximum rated external pressure?

Is there a calculation / rule of thumb that can determine a containers rough maximum negative pressure (vacuum) from it's rated internal pressure (assuming a single layer construction so there is no ...
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3answers
2k views

Minimum thicknesses of an elliptical cylinder pressure vessel

For pressure vessels in the shape of circular cylinders, we can use $\sigma_{hoop}=\frac{pr}{t}$ to find the minimum skin thickness by setting the hoop stress the maximum allowed value, and then ...
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2answers
530 views

How to remove protective valve cap from CO2 cylinder?

I have received a CO2 cylinder from an online seller fitted with a protective cap over the valve: I understand these should unscrew, but this one appears to be stuck very firmly. Is there a standard ...
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2answers
2k views

Determine force distribution from a bolt pattern

Need some help designing a bolt pattern for a pressure tight enclosure. How do i determine the force applied at a distance from a bolt location so that I meet the minimum force to compress the ...
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2answers
78 views

Why is the thin-walled cylinder more likely to experience failure along its axis than along its hoop/circumference?

I was watching a YouTube video to understand the concepts of hoop/circumferential stress and axial/longitudinal stress in thin-walled cylinders and their formula derivation. So the formula of the ...
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2answers
125 views

How does a pressure vessel fail when the interal pressure exceeds the yield stress of the material?

When we design a pipe or pressure vessel, we look at hoop stress and longitudinal stress and then look at the material properties. We assume that the material reacts to the load as a solid. However ...
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1answer
90 views

A question on mechanical failure

Suppose there is a rod, on the wall or at the centre, in a pressurized vessel, the pressure inside the vessel being P. The rod has a shear strength of S. Is it true that the rod will break, in shear, ...
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1answer
295 views

Is this pressure vessel feasible?

I am intending to construct a small pressure vessel. It needs to be around 7 centimeters in length and width and around 1-2 centimeters in depth. It must be capable of being pressurised to 300 psi ...
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0answers
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What's the best type of steam Trap for Superheated Steam?

Process Engineering Newbie here. What kind of Steam Traps are best suited for condensate removal in super-heated steam line or manifold? The super-heated steam is to be supplied to a process reactor ...
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0answers
31 views

How to apply the permeability value found from an experiment?

I have done a permeability experiment on LDPE in the presence of air using a 25mm circular specimen. At 30'C, the permeability was found to be 1.846 barrer. Now I am trying to apply this permeability ...
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2answers
811 views

How much pressure would I need to push water out of tank?

How much pressure would I need or, better yet, how do I compute for the pressure required to push water out of a submerged tank? Do I use 1 meter as head or 7 meters? (Please just bear with the ...
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2answers
207 views

Thin walled pressure vessel

What is the NORMAL STRESS in a thin walled pressure vessel? I am aware of only 2 types of stresses in thin walled pressure vessels: Longitudinal & Tangential. Is any one of these 2 is ...
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2answers
228 views

Why divide the dimensions of a pressure vessel by 39.37 when calculating discharge capacity?

For a National Board Exam Review: A 29.53" * 39.37" pressure vessel contains ammonia with f = 0.041. Compute the minimum required discharge capacity of the relief device in $\mathrm{\frac{kg}{hr}}$...
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2answers
17 views

Regulating pressure down inside vessel as it increases

I want to keep the pressure inside a balloon (effectively - a rubber vessel) constant, as the balloon is compressed. I'm wondering if a regulator like this (wiki page here showing mechanism - I ...
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4answers
438 views

Tubing for explosive gas or hydrogen transfer

Recently, I heard that there is a law/ OSHA/ ASME piece of regulation dictating that hydrogen should be transferred (suppose from a tank of hydrogen to another location) by using specially approved ...
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1answer
30 views

Can I increase the range of a howitzer by using more propellant?

The muzzle velocity of a firearm can, all else equal, be increased by lengthening the barrel of the weapon which can theoretically be extended up to the point that friction and air resistance would ...
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1answer
152 views

Check valve with precise cracking pressure

I have two containers of air, one at 100 kPa and rising, the other at 30 kPa and decreasing. I need a valve that lets air through when the pressure difference is >70 kPa. Where would I find a valve ...
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2answers
42 views

Choosing Pressure Vessel head

Can I use a conical head at the bottom for a small diameter steam manifold ( Schedule 40- 3 inch dia. and 2 inch dia. ) that needs to operate at high temperature (~450 deg Celcius) and High design ...
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1answer
81 views

What is this part called, and where could I get one?

I'm fairly illiterate when it comes to Engineering, so please understand I have pretty much 0 idea what I'm talking about. I'm having to build a seawater distillation device for school, and we ...
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1answer
85 views

Designing a horizontal pressure vessel

The question reads Design a horizontal pressure vessel with hemispherical head supported by saddle support and fitted with 2 nozzles welded to the head. It's used for storing and delivering fuel ...
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1answer
35 views

What is the criteria for bubble entrapment in a closed headspace tank set to drain?

Suppose a closed tank does not have any pressure relief system and is set to drain from the bottom. It is said that because the headspace pressure drops as the liquid level goes down, the tank will ...
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1answer
80 views

Why is gas pressure specified instead of mass flow?

Clarification: This question is all about the gas supply to the water heater. It has nothing to do with the water supply. My hot water heater specifies 5.5-10.5 W.C. (water column inches) of pressure....
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1answer
27 views

Collapsable Water Tank

I have been wondering, would it be possible to make an 8’x4’x’5 tank that can be put up and taken down as needed, where you would have a base, four removable corner posts, more removable posts as ...
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0answers
28 views

Why can't I find a small vacuum fryer?

I'm looking for a vacuum fryer and so far the only ones available to buy are large, industrial machines. Is there some technical consideration that makes small scale machines economically unfeasible? ...
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1answer
39 views

Are tube fittings a feasible way to create tight seal?

I'm doing an experiment where 2 electrodes are inserted into 2 openings in a cylinder holding electrolytes to measure its impedance. We want the openings to be tightly sealed because the cylinder ...
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1answer
1k views

When calculating the deformed radius of a pressurized thick-walled cylinder, why is the hoop strain used rather than the radial strain?

The context I’ve taken an interest in the design of pressure vessels for use in submarine applications. From a cursory survey of what is used in industry, it seems the de facto standard housing is a ...
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0answers
108 views

Equations for stress in a hollow prolate spheroid under external pressure

Are there analytical expressions (functions of geometry and applied pressure) for the stress in a hollow prolate spheroid, like there are expressions for the stress in a hollow sphere/cylinder?
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33 views

Pressure-volume relation of thin-walled shell [closed]

Attempt to edit into a more specific question as suggested by moderator: I would like define the shape and material properties of a 3D thin-walled shell/membrane-like structure (for instance a baloon)...
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3answers
930 views

Plane Strain examples

Trying to find examples of structures, components etc. in plane strain (under normal loading conditions). Is a thin-walled-pressure-vessel in plane strain? (I thought it was plane stress but could ...
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2answers
751 views

How to calculate external pressure resistance in spheres and cylinders?

Although I have seen a lot of literature online about how internal pressure resistance is calculated (i.e the pressure in a gas tank) I haven't found anything about the opposite scenario (i.e the ...
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1answer
90 views

How do you get a closed vessel to >90,000 psi internal pressure

Im trying to build a cold isostatic press with a internal vessel area of 300mm3. A cold isostatic press forms green metal components using pressures greater than 90,000 psi. Using an oil or water/...
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2answers
1k views

How to determine minimal wall thickness for a rectangular pressure vessel?

I know this is a basic question but google only gives formulas for more "rounded" shapes. How to calculate the minimal thickness for a flat wall knowing tensile strength of the material and the ...
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1answer
41 views

Wall temperature of pressure cylinder - Boundary condition

I have a thick-walled pressure cylinder, that transports fluid and experiences only internal pressure. During the process, the outer wall temperature is measured. And I have no clue about the inner ...
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1answer
62 views

Can a water pressure switch be used as a low-water cutoff means for a steam boiler?

Steam boilers obviously need to be protected from the catastrophe of running out of water -- you then either get a meltdown if the boiler is fired unwatered for an extended period of time or a boiler ...
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2answers
2k views

Liquid vs. gas check valves

Suppose that I want to transport gases in a tube in only one direction. Can a liquid check valve be used in place of a gas check valve or is there a specific reason to use only a gas check valve?
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1answer
254 views

Burst pressure of a sphere

Is there a formula for the burst working pressure of a spherical pressure vessel that takes into account its material peoperties? It should be noted that this is not a concentric sphere design (it has ...
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1answer
611 views

Will helium gas lift more weight in air when it is spread over large volume compared to equal weight heavily compressed small volume?

Is it possible for a weather balloons filled with helium gas to lift the weight of itself and a helium tank(highest psi possible) which can fit the volume of the lifting gas in it? Assuming a typical ...
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2answers
71 views

Ideal gas law, theory vs reality

I am trying to get an idea of the amount of hydrogen that I can store in some pressurized steel tanks underground. Based on the ideal gas law PV=nRT I did a simple calculation pressure = 200bar ...
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2answers
351 views

Measure stress of gas acting on a spherical container

How can I measure stress in a thin- walled sphere containing a gas? Is there a way to predict what the stress will be without actually needing to fill a sphere with gas? I am talking about hoop stress/...
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0answers
19 views

Angled Nozzle on Pressure Vessel - Weld Preperation

I wonder if anyone can help! I'm trying to model 3D geometry of nozzle to shell weld. I am having issues ascertaining correct bevel angle at a given point. Surely the bevel angle would change due to ...
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1answer
36 views

How could you produce large quantities of metallic hydrogen?

Could you somehow crush hydrogen atoms with magnetic fields in order to produce it? Or maybe someday someone will invent a material capable of withstanding 500GPa and we'll have giant machines that ...
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1answer
53 views

Analytical solution of thermal stress in a bi-metallic cylinder

As a side project I have looked to solve using Python an analytical solution for one-dimensional transient heat transfer in a thick cylinder with cladding on the inside surface, wherein the fluid in ...
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1answer
96 views

Kinetic energy of a balloon

How do I quantify how much kinetic energy would be released from popping a balloon? I believe that any additional kinetic energy that results from the balloon will come from it being pressurized, but ...
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1answer
28 views

hydrostatic storage of gasses

This question is a bit general but hopefully someone can point me in the right direction. If you have a metal container, welded shut that's fitted into a hole that is say 10 meters wide and 30 meters ...
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1answer
80 views

Flange EN1092-1 Type 21 Bore Diameter

How is the bore diameter of a flange Type 21 - acc. EN 1092-1 determinated? In the standard: NOTE 5 The bore diameters of flanges type 21 are not specified in this standard, the effective bore ...
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0answers
35 views

Thin or thick wall for expanding rubber pressure cylinder

If I want to expand a rubber cylinder by a certain internal volume - with all else held constant (type of material, length and radius (without constraining it), etc.) will a thinner or thicker walled ...