Questions tagged [compressed-gases]

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48 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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1answer
27 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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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 ...
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2answers
94 views

Calculating mass of gas in container

Given pressure is directly proportional to density, my understanding is that you can use the pressure of gas in a container to calculate the mass of the gas in the container. My reasoning being; $p=k\...
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2answers
57 views

Cheapest way to measure gas flow (mass)?

I understand that there are quite a few fairly simple and cheap methods to measure the flow of gas in terms of volume, allowing you to get a flow rate in terms of litres per minute for example. ...
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0answers
19 views

Modeling Friction-reduced Pressure Drop in Natural Gas Flowing along a Horizontal Cylindrical Trunkline (Pipe)

I am seeking some help related to part of a project I am currently working on, where I require to (data-driven) model the pressure drop due to friction for natural gas flowing along a horizontal ...
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1answer
18 views

Do you adjust gas flow rate (SCCM) to volume of chamber?

If I am carrying out a reaction by flowing 200 SCCM of a gas in a 20mm diameter pipe at 100mm length, if I change the pipe diameter to 10mm: Do I adjust the mass flow rate of the gases? If so, how do ...
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0answers
24 views

How to balance flow and pressure in nitrogen purged chambers?

I have an instrument that is technically a humidity controlled chamber. It measures how much moisture is picked up by the sample through a microbalance(Zone 1). Nitrogen gas flows from zone 3 and ...
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2answers
90 views

Is it standard practice to use a pressure relief valve as a pressure regulator?

I'm attempting to understand the difference between a pressure relief valve and a pressure regulating valve. From my research far, I've come to the following conclusion: Pressure relief valves are ...
2
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2answers
484 views

Lpg cylinder to compressed air tank

I am building a small robot having pneumatic system. I am using 12v car tyre inflator as my compressor.But i didn't find any 3ltr to 6ltr standardrd air tank. Can i convert my old 3ltr lpg tank into ...
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1answer
710 views

compare l/min output of CO2 pressure reducer to bar (compressed air)

I have a pressure reducer calibrated for Argon and CO$_2$ output. If I connected it to a gas tank with compressed air, how can I convert the output information "liters of Argon / CO$_2$ per minute" to ...
2
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1answer
235 views

volume comparison of compressed air and gas duster

I'm currently using 400ml Dust Off 67 gas dusters and want to replace them with compressed air and a blow-out gun. In order to select the right equipment and get a better understanding I would like ...
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1answer
2k views

Why was Freon used in spray cans before it was declared a threat to ozone?

I've heard that in the past, spray cans (aerosol cans) contained Freon. I found that the Montreal Protocol made the usage of Freon illegal due to its effect on the ozone layer, but I can't find the ...
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51 views

Roskam Book equation of dry air density is not clear. I need explanation

Preface: Roskam in book "Airplane Aerodynamics and Performance" explains (in paragraph "1.1 ATMOSPHERIC FUNDAMENTALS"): To determne how water vapor affects air density, consider a given volume ...
2
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1answer
555 views

Isentropic flow equation derivation

I am trying to derive the isentropic flow equations for a compressible gas by myself and at the end, I have different formulation than the one in the literature. Can you please tell me what am I doing ...
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1answer
445 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 ...
2
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1answer
2k views

How to determine the choke point in a compressed gas system?

I have a pressure regulator bringing an inlet pressure of 150 bar down to 10 bar which is then lead into a plenum followed by a nozzle of area 340 mm^2, exposed to atmospheric conditions. Weirdly ...
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1answer
58 views

Device (electronic valve?) for controlling O2/Nitrogen levels in sealed chamber

I'm designing an environmentally sealed chamber which will need to have its oxygen level controlled. The chamber has a volume of roughly 1.5 liters. I don't expect pressure to vary too much ... ...
4
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1answer
625 views

Velocity of flue gases through a pipe

I was wondering if there is any equation that helps to calculate flue gas velocity through a pipe? Can I use the Poiseuille Equation to solve this problem by assuming the flue gas is acting as a ...
2
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2answers
457 views

Why no hydraulic piston gas compressors?

I've been looking at solutions to compress gases and getting stunned by the cost and maintenance requirements of existing systems to fill cylinders (whether for SCBA or chemical storage) to 2000-...
2
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1answer
1k views

Valve for mini CO2 gas canister?

I am in the process of helping my son design a sort of model of the Bloodhound SSC car for his school project, using balsa wood, model aircraft wheels, etc... It doesn't have to a like of like, but ...
3
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0answers
36 views

Advice on Literature pertaining to transient pipe flow with heat transfer and friction [closed]

For a project I am working on I need to model the flow of argon in a long pipe. The flow is transient in nature since the tanks and regulator from which it enters cause the mass flow to change. ...
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2answers
1k views

Air compressor that doubles as a pneumatic motor?

I am working on a compressed air energy storage system. The size and weight of the system are heavily constrained; nothing should (ideally) exceed a few pounds. For this reason, I would like to store ...
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2answers
812 views

What are the advantages of chemical oxygen generation over compressed tank storage?

Chemical oxygen generation (COG) is used in commercial airliners to supply emergency oxygen to passengers and crew if the plane is depressurized. Weight for weight it produces far more oxygen than ...