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 ...
Chris Johns's user avatar
  • 15.2k
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-...
Daniel K's user avatar
  • 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 ...
niels nielsen's user avatar
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 ...
kamran's user avatar
  • 22.4k
3 votes

What are these bent shapes on this elbow in a compressor suction pipe?

I suspect that the crescent shaped sections penetrate all the way through the pipe and are turning vanes to help direct the flow around the sharp corner. In pipe of this size it is much easier to ...
Chris Johns's user avatar
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3 votes
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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 ...
Fred's user avatar
  • 9,637
3 votes
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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 ...
user1683793's user avatar
  • 1,000
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 ...
Secundus's user avatar
  • 571
3 votes
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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 ...
ericnutsch's user avatar
  • 8,106
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 ...
niels nielsen's user avatar
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 ...
Solar Mike's user avatar
  • 15.7k
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-...
Phil Sweet's user avatar
  • 4,755
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 ...
totalynotanoob's user avatar
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 ...
Sherwood Botsford's user avatar
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 ...
achrn's user avatar
  • 632
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 ...
mart's user avatar
  • 4,771
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 ...
Dan Mills's user avatar
  • 251
2 votes
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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.
Solar Mike's user avatar
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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 ...
Phil Sweet's user avatar
  • 4,755
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 ...
Phil Sweet's user avatar
  • 4,755
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 ...
Suryetto's user avatar
  • 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 ...
blacksmith37's user avatar
  • 6,134
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 ...
J. Ari's user avatar
  • 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 ...
Jeffrey J Weimer's user avatar
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 ...
Tiger Guy's user avatar
  • 6,871
2 votes
Accepted

Why are double-acting reciproating compressors more efficient than single-acting ones?

You will find losses in a single acting compression such as leakage, even with a seal as the pressure difference is high, any leaked fluid in a dual acting compressor is less of a loss as it leaks ...
Sami Safarini's user avatar
2 votes
Accepted

Is it possible to use two sets of stator blades after each set of rotor blades in an axial compressor?

You are completely missing the point of how an axial compressor operates. Let's say you design it so the axial velocity everywhere in the machine is a constant 2.5 m/s. The area of the flow will ...
Phil Sweet's user avatar
  • 4,755
1 vote
Accepted

Pressure delivered to an object under a pneumatic press

This looks right- but note the units of pressure (not force) experienced by the red object are pounds per square inch.
niels nielsen's user avatar
1 vote

If the turbine drives the compressor, then what limits the engine speed?

Simply put, fuel. Fuel is the source of energy by burning and expanding the flow of air in combustion chamber, and the flow of fuel is controlled by the pilot. Pilot or auto pilot, have a chart and ...
kamran's user avatar
  • 22.4k
1 vote

Define Free Air Delivery for an air compressor

Build up to the formula (is $F_2$ a typo for $P_2$?) one step at a time. In the simplest situation, $V_1 = V_2$ (which should be obvious to everybody in the room). But for a real compressor test, ...
alephzero's user avatar
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