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Questions tagged [compressed-air]

94 questions
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Why are train brakes so complicated?

The concept is simple enough: no pressure in the train line has the brakes locked, full pressure is loose, and partial pressure drags accordingly. So if pressure is lost for any reason, the train stops. (or at least it's supposed to; more on that…
AaronD
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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 reason for why Freon was used in the first place. I…
Physther
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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 the energy (compress the gas) and extract the…
MikeJava
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Why does public transport uses compressed air to open doors instead of electromotors?

System with compressed air seems more expensive and harder to build and integrate neither using simple electromagnetic drives to open public transport doors.
PaulD
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5 answers

Is compressed air energy storage economically viable in the home?

If I install a small air compressor/engine, generator, and tank in my garage, and I charge it up at night when electricity costs $\frac{5.4p}{kWh}$ and use it during the day to power my house when electricity costs $\frac{12.5p}{kWh}$ would this be…
jhabbott
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Are there any precedent designs for a mechanically-delayed pressure release valve?

I need to release pressure of around 50psi, after 3-4 seconds of initiating, from a vessel using a mechanical switch. I had considered a pneumatic solenoid, but I want to forgo the inconvenience of charging the device with electricity in addition to…
SmugDoodleBug
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2 answers

Turning an engine over with engine compression

When you compress a bicycle pump and seal the opening, the pump will automatically return to it's initial position when you release it. I suppose this is how air suspension works as well? if you have a internal combustion engine without any gas and…
Erik
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Tankless air compressor for electronics desoldering station

I purchased a Weller WSD161V soldering station (similar to this one, at least with regards to the pneumatic system I'm about to describe -- sorry, I was unable to find a manual for my specific model on the internet) with a DSX80 desoldering…
swineone
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Simplifying head loss across a piping network

I am tasked with designing a compressed air piping network,with and would like to determine the pressure loss across the different layers of instruments -now here is the 3D layout of the network. The blue circles are instruments I want to deliver…
udidosa
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How do you actually control the cooling level of AC?

I'm hoping this is a relatively simple question to answer, but I just couldn't find it on Google. With regard to air conditioning (or any cooling system that relies on compressing/evaporating), how do you actually control the 'cooling' temperature?…
Izzo
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Estimating Maximum Speed for a Pneumatic Cylinder

I am designing an machine that is going to use a pneumatic cylinder to accelerate a projectile. I have a tentative cylinder specified, and am working on the control and supply side. I have verified that I can generate enough force, have enough air…
Ethan48
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Pneumatic Actuators - System Reversibility. Is it possible to use an actuator to store energy?

I'm very much new to pneumatics and I was wondering if there was such a thing as a reversible pneumatic actuator? I'm designing a system that has to be lightweight, pneumatic and use a mechanical input to store energy in a pneumatic manner. The…
Alex
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Specific heat at constant volume used in non constant volume processes

I have commonly seen that the work for an isentropic compression is written as: $$ W_{in} = c_{v}(T_1 - T_2) $$ What confuses me is that since it is a compression (volume is changing) why do we use the constant volume specific heat? Thank you…
STOI
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How to design a hemispheric flexible pressure vessel?

Consider a balloon, it is a flexible, expanding pressure vessel made of synthetic rubber. I am trying to design a system that will use hemispheric pockets of neoprene to grip an object, much like the one found in this journal: H. Choi and M. Koç,…
Sam Weston
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What's the difference between a vacuum regulator and pressure regulator?

When browsing through pneumatic parts, I notice that some vendors specify different components for pressure regulator and vacuum regulators. SMC for example does this. I'm curious why vendors would actually need to differentiate vacuum regulators…
Izzo
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