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2
votes
1answer
54 views

Do pressurised cans still pose a risk to bursting in normal conditions, but after being exposed to heat?

We're planning on shipping some items from the US to Australia as you cannot get them here, that being: https://www.chewy.com/sentry-stop-that-noise-pheromone-dog/dp/56486 I have been in contact ...
2
votes
0answers
61 views

Injecting CO$_2$ into water: how does injection work?

I've been wanting to design my own water carbonation device for a while. For reference, I've been looking at devices like the Sodastream, which injects pure CO$_2$ into water to dissolve it with up to ...
0
votes
2answers
49 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 ...
2
votes
0answers
16 views

Parts needed for controlling vacuum line pressure with pressurized nitrogen

I'm trying to assemble a simple setup where a line which is typically under vacuum can be pressurized by an external nitrogen supply, with this pressure regulated to less than 1 bar absolute (let's ...
0
votes
1answer
239 views

Programming a gas mass flow controller rig

I'm trying to upgrade a multiple gas flow controller, which must be capable of controlling the mass flowrates of three gases independently through one outlet line to our system, and am in need of a ...
0
votes
2answers
28 views

Measuring gas flow from a low-output device

My lab uses a home-built biomedical instrument that acts as a ventilator for test-subjects. In other words: our device combines nitrogen and oxygen gases and pumps them down the line at a specified ...
1
vote
1answer
70 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....
2
votes
2answers
44 views

Can I improve this exhaust gas probe to be immune to pressure changes?

I'm designing a probe to provide a stable and continuous stream of exhaust gas sample to an analyser. The probe has to be inserted into the exhaust for about 20–30 cm to keep outside air from entering ...
3
votes
1answer
126 views

Can mercury escape undectectably from a CFL bulb? or does it have to shatter for the mercury to be liberated?

I read that the mercury vapour inside a fluorescent lamp is pressurized at 0.2% of atmospheric pressure. Can mercury escape undectably through a small crack in the glass yet still light up? Or will ...
1
vote
1answer
79 views

Helium is leaking through manometer

I have connected a 200 bar helium tank and a manometer to a pressure regulator. The end of the manometer's tube connected to the regulator is leaking. It's attached with anaerobic thread sealant, so I ...
1
vote
1answer
84 views

Pressure Differential Analysis

In these units: cm³.20μ/m².24hr.atm - (definition) cubic centimeters for a 20 micron film thickness per square meter per 24 hours under a pressure difference of 1 atm. My question is what does the "...
1
vote
0answers
43 views

How to convert permeation units to molecules/second?

How do I convert $\dfrac{\text{cm}^3\cdot\text{mm}}{\text{m}^2 \cdot \text{day} \cdot \text{atm}}$ for permeation of gas through EVOH to molecules of gas permeating per second as a function of ...
0
votes
1answer
67 views

Understanding Permeation Units

I have encountered a type of unit that I cannot understand. The unit describes the rate of permeation through a substance:(cm^3 . mm)/m^2 . d . atm Could someone please explain how to interpret ...
5
votes
1answer
716 views

How do gas flow regulators avoid choking?

According to compressible flow theory, a downstream pressure of 0.528 times upstream pressure is sufficient to choke a flow device. So, how do industrial grade pressure regulators throttle a wide ...
2
votes
3answers
10k views

How to calculate the velocity of gas in a pipe?

I was wondering how I can calculate the velocity of gas through a pipe. The gas, assuming ideal behavior, in a pipe (cylinder) of volume of 222.4 L has a pressure of 1.95 atmospheres and a density of ...
3
votes
1answer
4k views

Working out pressure drop from leak rate

I am trying to work out the acceptable pressure drop/increase on a leak test rig for a given leak rate. A simplified version of the test rig looks like this: The gas (air) supply is at 1 bar above ...
1
vote
1answer
69 views

Calculate pneumatic cylinder dimensions from work done

I have a project for which I need a pneumatic cylinder to impart an impact force in such a way that work-done/energy is 4.5 Joules, and the input pressure is 10 bar. How can I solve this so that I ...
2
votes
2answers
622 views

Pressure drop across column in gas phase: what changes?

If you force high-pressure gas through a packed-bed, the gas pressure drops. However, the ideal gas law states: $$P = \frac{RT}{v}$$ so for an ideal gas, the pressure drop must be associated with a ...
6
votes
1answer
104 views

Multi-gas barometric height formula in isotope separation devices?

I think, actually the first row is needed is a barometric height formula for the mix of gases. The main problem I can see, the curves describing the minimal energy (kinetic + gravitational/...