5
votes
Accepted
Why no hydraulic piston gas compressors?
There are two aspects to this. First is that the main advantage of hydraulics is that is provides a compact means of greatly multiplying force but in compressing gasses you have to a huge amount of ...
- 15.1k
5
votes
Is it safe to use a 125PSI rated auxiliary air tank with a 150PSI air compressor?
Don't do it!!
Just buy a pressure regulator to put between the two tanks that will decrease the pressure to below 125. You can get these for \$17 at home depot (https://www.homedepot.com/p/Husky-1-4-...
- 2,646
4
votes
What is diffusion in the context of compressor?
An axial compressor accelerates a flow of air to high speed. All the molecules in that parcel of air have that speed superimposed on their random vibrational motion. The idea of a diffuser is to get ...
- 14.1k
4
votes
why do centrifugal compressors have curved blades?
As the air moves from the center out it accelerates in a pattern similar to a hurricane. the velocity vector angle changes to reduce the rotational whirlpool and angular momentum component of the ...
- 21.8k
3
votes
Air Conditioners: Compressor Explosions?
That's a pretty qualitative question, but by and large, air conditioner compressors are not really inherently dangerous to be around. Danger comes in the form of unqualified people working on or ...
- 561
3
votes
Accepted
Is a 3 Hz beat frequency from my neighbor's HVAC a sign of a malfunction?
A 3Hz pulsating hum-- noise that is getting louder and softer at 3Hz. Yes, I agree that would be quite annoying.
Since this is a residential unit in the US, both the compressor and the fan are run ...
- 980
3
votes
Accepted
What is the difference between a piston and a plunger compressor/pump?
Per the Plunger Pump Wiki:
A plunger pump is a type of positive displacement pump where the high-pressure seal is stationary and a smooth cylindrical plunger slides through the seal. This makes ...
- 7,794
3
votes
Accepted
What are these bent shapes on this elbow in a compressor suction pipe?
Notice that the "shapes" are in a right angled bend where the flow changes directions.
Sometimes vanes are placed in right angled bends to reduce shock losses by reducing the turbulence of the flow ...
- 9,582
3
votes
Compressing gas with liquid
Yes indeed, air can be compressed by pressurized liquids directly as you suggest. However, there are problems that accompany this sort of scheme.
First, if the gas is significantly soluble in the ...
- 14.1k
3
votes
why not put the compressor right next to the evaporator?
The evaporator is usually in the area to be cooled ie where the people work, read etc
As the compressor takes space and tends to be noisy it is located away from that area. That makes the system in ...
- 15.3k
3
votes
Regarding design of a compressed air delivery system based on a screw air compressor
That is on the high pressure end of normal pneumatic conveying blowers, but they are out there. See the notice at the bottom of the attached chart.
http://www.hsiblowers.com/products/high-speed-turbo-...
- 4,322
3
votes
Why do high pressure multistage air compressor have different piston diameter sizes?
There is a simple reason and a useful added benefit.
As you compress air of a fixed mass it occupies less volume. If you give it more space again, it will immediatly decompress and the multiple ...
- 361
3
votes
Accepted
Slow Driving an Air Compressor
Google dugout aeration windmill system.
There are various makers. Here's one: https://koenderswatersolutions.ca/
The compressor on them does one cycle per revolution of the windmill. While not as ...
3
votes
why do centrifugal compressors have curved blades?
They aren't universally.
Centrifugal fans use all sorts of blade configurations - forward, backward, radial, curved (either forward of backward) and straight (also prismatic or aerofoil). Different ...
- 632
2
votes
Accepted
How can flow in a centrifugal compressor at fixed conditions vary?
In general every compressor (axial and radial) will deliver a certain flow rate depending on the back-pressure down stream of the compressor. So by changing the pressure difference over the compressor:...
- 1,192
2
votes
How can flow in a centrifugal compressor at fixed conditions vary?
The generic equation for mass flow through a cross-section of area $A$, traveling at velocity $V$ is
$$
\dot m = \rho \, V \, A
$$
where $\rho$ is the density of the fluid and $\dot m$ is the mass ...
- 3,044
2
votes
Accepted
Gigapascal pressures in a small package
Such high pressures can be achieved via diamond anvil cells (DAC). The heart of these cells are two diamonds mounted on tungsten seats symmetrically in front of each other which are separated by ...
- 136
2
votes
Could an air compressor be used to compress steam?
You are describing Vapor-compression Evaporation. According to wikipedia, since any real compression will also heat the gas "The compression work will deliver the steam superheated if compared to the ...
- 4,705
2
votes
Accepted
Compression and check valves
No, because the pump is designed to limits and if you exceed its working or maximum pressure then, for example, its seals fail and it just does not pump any more.
- 15.3k
2
votes
Why no hydraulic piston gas compressors?
The elephant in the room is that while gasses are compressible, hydraulic oil is only negligibly so.
This difference has two major effects:
Firstly, the output volume flow is limited by the intake ...
- 241
2
votes
What is the reason for a reduction in entropy in a compressor
\begin{equation}
{\displaystyle \Delta S=nC_{v}\ln {\frac {T}{T_{0}}}+nR\ln {\frac {V}{V_{0}}}.}
\end{equation}
Snipped from Entropy: wikipedia.
See also 5.4 Entropy Changes in an Ideal Gas, which I ...
- 4,322
2
votes
why not put the compressor right next to the evaporator?
What you describe is quite common where there isn't any problem with power and noise. It requires a bit more sophistication to manage the superheat. And yes, you need to quiet the thing some. I ...
- 4,322
2
votes
How do stators in axial compressors work?
Compressors are a combination of rotors and stators along a structure with reducing cross-section area. The rotors spin and push air down the compressor, but due to their spin there arises a ...
- 119
2
votes
How to decrease Nitrogen gas consumption in Iron & Steel Plant?
I have been in 100 steel mills and never noticed a nitrogen system. However it seems they could use inert gas blasting somewhere. And nitrogen would be so cheap and convenient because steel mills will ...
- 6,102
2
votes
Is it safe to use a 125PSI rated auxiliary air tank with a 150PSI air compressor?
A 10 or 25 psig overpressure of a tank is well into a potential failure for the tank. The 140 psig safety valve is used because that accounts for the true pressure capability of the tank plus the ...
- 478
2
votes
Accepted
Specific heat at constant volume used in non constant volume processes
Start with the first law.
$$dU = \delta q + \delta w$$
Isentropic sets $dS = \delta q /T = 0$, giving $dU = \delta w$. For an ideal gas with a constant specific heat, $dU = C_v dT$. This gives the ...
- 2,878
2
votes
Axial compressor: How does it work that the stator vanes diffuse the flow to build up pressure, but also the flow area reduces?
The device has to be designed so that each stage does its job.
The stator reduces the high velocity out put of a stage to a lower velocity, increasing the pressure. But the subsequent rotary section ...
- 6,248
1
vote
Accepted
can we run rotary compressor of Air conditioner with different frequency level?
The answer is, we don't know what compressor you have so we can't answer definitively. MANY compressors are indeed designed to operate at a very narrowly specific speed because the lubrication of it ...
- 126
1
vote
What will remain constant during the circulation of working substance in a refrigerating machine?
Depends how far you want to go with the modifications.
You can change the working parameters of the pump, changing the flow rate. While you can't meaningfully reduce the volume of the coolant in ...
- 6,125
Only top scored, non community-wiki answers of a minimum length are eligible