Questions tagged [compressed-air]

The tag has no usage guidance.

Filter by
Sorted by
Tagged with
12
votes
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 ...
9
votes
2answers
2k 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 ...
7
votes
2answers
2k views

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.
7
votes
5answers
8k views

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 ...
5
votes
1answer
482 views

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 ...
4
votes
2answers
390 views

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 ...
4
votes
1answer
112 views

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 ...
4
votes
3answers
52 views

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 ...
4
votes
1answer
1k views

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 ...
4
votes
0answers
926 views

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 ...
3
votes
3answers
229 views

What is the best method to generate heat from a compressed air canister?

I want to convert the pressured air exiting a valve to heat. I know that a vortex tube can be used to do this, but I am wondering if I need to make modifications to the vortex tube to make it more ...
3
votes
2answers
408 views

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 ...
3
votes
2answers
2k views

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 ...
3
votes
2answers
281 views

Check valve in compressed air pipe network?

I am working on a building that would like to used compressed air for some pneumatic actuators. They would like to bring the air in from an adjacent building that has more than enough capacity, but ...
3
votes
2answers
84 views

Compressed air energy storage?

I'm wondering, if you put an air compressor pipe into a micro turbine, lets say something like that attached to a motor, does air that get out of the turbine have the same energy as when it gets in ? ...
3
votes
2answers
320 views

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 ...
3
votes
0answers
87 views

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. ...
2
votes
1answer
67 views

Why air compressing mechanism “Trompe” is not popular in usage?

I was amazed when I got to know that there is such a simple mechanism know as Trompe to compress air. It has no moving parts which make it cheap to construct and do not require any servicing. Even the ...
2
votes
1answer
37 views

Slow Driving an Air Compressor

Do off-the-shelf air compressors have minimum driving speeds, below which they cannot build the necessary pressure? Reciprocating compressors and scroll compressors are available—is there a difference ...
2
votes
1answer
315 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 ...
2
votes
2answers
761 views

How to calculate added lift from ground effect

I'm trying to build a hovercraft of sorts, and I thought I'd take advantage of the ground effect. I've done some searches, but I can't seem to find any guides on the actual physics. How do I go about ...
2
votes
1answer
89 views

Recommended compressed air source and location for separate air compression system

I am investigating what would be the most appropriate compressed air source (fan/blower/compressor) for designing a separate air compressor system. The information is as follows: the compressed air ...
2
votes
1answer
230 views

Air tool to compressor backflow

As I was reorganizing my air tool arsenal, a theoretical question popped in my mind I'd like to know the answer to. In designing air flow between an air compressor and a tool (such as a nailer or an ...
2
votes
0answers
32 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 ...
1
vote
4answers
462 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 ...
1
vote
1answer
41 views

Is using your mouth and lungs to blow away dust inside your computer somehow bad for the computer?

Bottles of compressed air are very expensive where I live. While it would be nice and ideal to have and do a "proper" cleaning, I've always used my mouth and lungs to blow air onto the dust ...
1
vote
2answers
39 views

Compressing gas with liquid

This question, in short, is: Can a gas be compressed with high pressure liquid? As a scenario, imagine a tank full of atmospheric gas at STP. Could something like a pressure washer pump (in this case ...
1
vote
3answers
432 views

How do you read a blower/compressor curve with multi-curves for inlet guide vanes?

I am trying to apply an existing blower curve in a hydraulic model for a single stage blower with variable inlet diffuser vanes. The variety of curves shown on the plot does not seem to make sense to ...
1
vote
4answers
256 views

What type of air blower/compressor to use?

I need a way to move air which is somewhere in between a compressor and a fan: something along the lines of 20-40 cfm at 2-3 psi (500-1000 liters/minute at 10-20 kPa). Typical small compressors (of ...
1
vote
1answer
4k views

Basic difference between “compress” and “pressurise”

We call air which is pressurised as "compressed air". But we don't call pressurised liquid as compressed. I know that liquids are incompressible. So, why particular word "compressed" is the created, ...
1
vote
2answers
54 views

How can I build a regulated pressurised air supply?

I need a source of air pressure for an air bearing (3D printed cylinder that expands air upwards like an air hockey table). I would like to be able to control the flow of air. I don't have a lab air ...
1
vote
1answer
39 views

What is this “johnson controls” device on the wall in airport?

I was passing column in waiting area of Pearson airport when my sweater cought some kind of device on the wall. Device was without cover and looks like old thermostat. When my sweater caught it, it ...
1
vote
1answer
27 views

Cumulative effect of two axial fans

If I already have a small DC axial 2m3/h fan blowing air at something, what will happen if I add a larger more powerful 6m3/h DC axial fan blowing from behind that one (i.e. its the larger fan first, ...
1
vote
1answer
3k views

How do you interpret a pneumatic regulator symbol?

I'm an EE trying to interpret a pneumatic schematic and have a few questions regarding the symbols being used. I've come across two different regulator symbols (or so I believe them to be regulator ...
1
vote
2answers
19k views

Define Free Air Delivery for an air compressor

Free Air Delivery (FAD) is a common measure of the capacity of an air compressor. I have a question that comes at the end here. My question is a little different from what you might be expecting. So ...
1
vote
1answer
131 views

can we run rotary compressor of Air conditioner with different frequency level?

I am working on split type AC compressor. I actually want to know, if i changed the frequency of the compressor to run on different power level, will it affect the life of the compressor. My actual ...
1
vote
1answer
40 views

Are “Imperial Eastman” compression connections sized the same as regular imperial connections?

I have some high pressure and vacuum lines off of a tool from the 1980s and they are labeled as, for example, "3/8 imperial - eastman," which seems to be different from how normal compression ...
1
vote
1answer
45 views

How to calculate rock permeability in m^2 from gas flux in m/s?

I am studying rock caverns lined with concrete for compressed air storage. I would like to know if it's possible to convert the permeability coefficient from m/s to m^2 or Darcy. Thank you.
1
vote
0answers
24 views

Why does use with air or water reduce the maximum temperature of certain high temperature / pressure hoses?

This example is a Parker Hannifin model 426/436 "SAE 100 R1 AT / SAE 100 R16 High Temperature Hose". Here are the temperature specifications: (Full data sheet) Although there is an asterisk ...
1
vote
1answer
22 views

How do cavity resonators differ from tubes of uniform width?

I read that wine bottle produces sound when u blow sideways onto its rim because some frequencies of the white noise produced in your mouth gets amplified when they match the natural frequency of the ...
1
vote
0answers
88 views

What happens when throttling in an isothermal process

Consider an isothermal expansion of an ideal gas (always at ambient temperature $T_0$), from some initial pressure $p_i$ to the ambient pressure $p_0$, such that the maximum work available is: $W = ...
1
vote
1answer
67 views

pneumatic solenoid operation?

Any idea on how this type of pneumatic solenoid works? I know that NC is normally closed, NO normally open, but not sure how air flows? Thanks!
1
vote
1answer
59 views

How to power and transport air to a small hover car track [closed]

I'm trying to design a hover car track. As in, you have a 'track/circuit' that have objects being slowly moved along by the force of the air from beneath and sides. The propulsion to move the objects ...
0
votes
2answers
3k views

Can Compressed air be used as a thrust component in a spacecraft to propel the craft through space or to orient the craft? [closed]

Hello I was watching a video recently about aircraft carriers and how they use compressed air to propel aircraft off the ship. It go me thinking if I had, maybe a 50cm x 50 cm x 50 cm spacecraft that ...
0
votes
1answer
44 views

Why do high pressure multistage air compressor have different piston diameter sizes? [closed]

I meant like this kind of compressor https://www.bauer-kompressoren.de/fileadmin/_processed_/csm_compressor-block-junior2_b92a76a02e.jpg also would the compressor reach high pressure if the diameter ...
0
votes
2answers
71 views

Regarding design of a compressed air delivery system based on a screw air compressor

I want to select a screw compressor for my application wherein I need a pressure of about 18 psig, and 300 cfm at the aforementioned pressure. The compressors I'm finding suitable for the system have ...
0
votes
2answers
51 views

What is the idea behind an expansion valve?

I am watching this video(https://www.youtube.com/watch?v=gVLhrLTF878) and beginning at around the 2:20 mark, it explains the significance of an expansion valve with the following ideas: Restricts ...
0
votes
1answer
29 views

Compression and check valves

Pressure pumps are used to apply pressure to a system. What would happen if someone attempted to fill, for example, a bicycle tire (with a check valve) to 2 ATM of pressure using a pressure pump that ...
0
votes
2answers
35k views

How does loading and unloading work in an air compressor?

I am looking at an ammonia refrigeration unit and trying to understand how loading and unloading solenoid valves work? and also how to modulate the compressor motor over a period of time.
0
votes
2answers
51 views

What is the maximum temprature that could be achieved by compressing air?

We know that compressing air produces heat but is it possible to achieve temprature of 700degree C just by compressing air. If not what will be the maximum temprature that could be achieved?