What is Compressors: Definition and 38 Discussions

A compressor is a mechanical device that increases the pressure of a gas by reducing its volume. An air compressor is a specific type of gas compressor.
Compressors are similar to pumps: both increase the pressure on a fluid and both can transport the fluid through a pipe. As gases are compressible, the compressor also reduces the volume of a gas. Liquids are relatively incompressible; while some can be compressed, the main action of a pump is to pressurize and transport liquids.
Many compressors can be staged, that is, the fluid is compressed several times in steps or stages, to increase discharge pressure. Often, the second stage is physically smaller than the primary stage, to accommodate the already compressed gas without reducing its pressure. Each stage further compresses the gas and increases its pressure and also temperature (if intercooling between stages is not used).

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  1. H

    Why do we need stators in compressors or turbines?

    Hey Everybody! I was wondering why do we need Stators in compressors and turbine, for instance the goal of compressor is to increase the outlet pressure, so that the combustion is effective, but why we don't put just Rotors and no stators in the compressor (or Turbine).
  2. jack action

    Auto/Motor Can a Piezo Lighter Ignite Spray Packs for Tire Inflation?

    source: www.facebook.com/engineeringinsider/videos/2997360803650345/
  3. S

    Pressurizing Argon Gas: Pump or Compressor Options?

    I need to pressurized argon gas from 1 bar pressure to 2 bar pressure. Flow rate outlet is 0.5 LPM. Can anybody suggest me a pump or compressor which is small in size? Minitiarised diaphragm seems good option but is it right one?
  4. D

    How does air behave in the daisy chaining of compressors?

    I'm working on a project involving compressing air to a desired high pressure. So far the only equation I've been paying attention to is the ideal gas law. My question is if an air compressor pump is rated to create a maximum pressure of 100 psi based on its inlet being at atmospheric pressure...
  5. marcophys

    Calc L/min air compression to different pressures & temps in my compressor

    I have acquired a new compressor rated at 540 L/min @ 7 bar 150L tank I decided to test this at 23 degC, timing compression at 2 bar intervals (0-2, 2-4 etc.) I was surprised to find that it maintained 34 seconds at each interval up to 8 bar (but this could be poor experimental...
  6. P

    What kind of air compressors are better?

    I want to know which kind of compressors are best for compressing very cold air. I mean as cold as they can operate in Antarctica during the winter when the temperature will reach around -50°C. In fact, I am looking for compressors that can withstand lower temperature of around -90°C. But, which...
  7. P

    What are the efficiencies of steam compressors that are available?

    For some purpose, I need a steam compressor that can compress sub atmospheric level steam to atmospheric and above. I want to know what's the efficiency of an average steam compressor available in market. I have got some replies from a few steam compressor manufacturers, but the system they are...
  8. A

    Why do air compressors make sounds?

    Why do compressors for example in the fridge make that vibrating sound, I've heard a similar vibrating noise in fans which are compressing air as well... i think. Why does compressing air make sound? Can air hitting air create sound waves?
  9. S

    Can an Air Compressor Run on 12v and Deliver 150psi Continuously?

    Is there an air compressor that can run on 12v continously delivering 150psi?
  10. Rx7man

    Centrifugal compressors, adiabatic compression

    Homework Statement I am working on creating a spreadsheet where you can input the parameters of an engine at a given rotational speed such as volumetric efficiency, boost pressure, atmospheric pressure and temperature, and compressor efficiency... It's been a very long time since I've done...
  11. R

    CO2 laser recirculation compressors and coolers

    Does anyone know what the best recirculation compressors are for a high power CO2 laser. I would like a small foot print low flow positive displacement compressor (rotary vane or diaphragm maybe?) that is not an expensive noisy monstrosity for maybe a $100 or so. Also does anyone know of a...
  12. Vlad137

    Physics behind turbochargers and compressors

    Hi everyone, I need to do a presentation to a high school class about the physics behind a turbocharger and was looking for some help getting which principals/laws explain what happens when a turbocharger is used within a car i.e.; Thermodynamics, gas laws. I just need a direction in which...
  13. I

    Compressors in coolant systems

    I'm told the delay time (the time i turn down the thermostat and the time the AC kicks in) is a safety measure to let the coolant pressure equalize. I don't really understand why.
  14. T

    Learning About Reciprocating Compressors for Oil & Gas Engineers

    Dear All, I am a mechanical engineer who has recently started working in the oil& gas industry (compression). I would appreciate if someone can guide me to where can I learn about reciprocating compressors. Much appreciated.
  15. A

    Settling the Debate: Air Compressors & Koi Ponds

    I wonder if someone can help settle a debate I am having over using air compressors to aerate garden koi ponds? A typical pond will have a small electric air pump (44W rated, delivers say 50 litres a minute at 1.5 metres deep in a 10000L pond) blowing air through a diffuser to add oxygen and...
  16. P

    Refrigerator Compressors Already have Refrigerant?

    I am a little confused, because I know how refrigerators work with a refrigerant and a compressor and heat exchanges, and I am looking to build one myself, just wondering because I was looking for refrigerator compressors online to buy. Do they have an inlet for refrigerant or is the...
  17. F

    Centrifugal Compressors - volumetric flow and pressure ratio

    Hi all, I am relatively new to compressor theory and I am looking for a good explanation as to how volumetric flow affects pressure ratio between the stages within a centrifugal compressor. My current knowledge is that as volumetric flow decreases, pressure ratio increases as stated in one of...
  18. C

    Car AC Compressors: Speed Control & Temperature Regulation

    How is the compressor speed controlled in a car air conditioner, in compressors driven by engine moved belts? Is temperature controlled just by on/of of the solenoid clutch? Electric air conditioner (automotive), not driven by (directly) by engine, is widely used today? Another question, not...
  19. Y

    Calculation of power input in air compressors

    Can anyone give me a type for calculating the power input on air compressors ? Thanks in advance !
  20. U

    Centrifugal compressors some details on work done and vane angles.

    1. As far as the derivation goes, Cp(T02-T01)= Euler work= U2Cx2 in a centrifugal compressor... where T01 and T02 are the stagnation temperatures...however, in a solved problem in my book, it writes: Cp(T2-T1)= Euler work= U2Cx2...and therefore uses static temperature instead of stagnation...
  21. U

    Differences between basic definitions for compressors and turbines

    While making a comparative study between turbines and compressors, I noticed some differences between the way they are studied...pleasehelp me understand why these differences exist... 1. Efficiency for a turbine = (actual work/ideal work) whereas for compressors, it is (ideal work/actual...
  22. W

    An odd thought on centrifugal compressors.

    Hi everyone I'm new. I had an odd thought when thinking about centrifugal compressors. Take a normal straight veined compressor. Normally it just sucks the air straight in and has to accelerate it effectively from zero to however fast it ends up going. But what of you modified the...
  23. D

    How do I design a two-stage compressor for a homemade jet turbine?

    Hey guys and gals! first time poster so be gentle...I'm wanting to make a small jet turbine from scratch but I am totally baffled by how to design the compressor and turbine stages for compressing the air and extracting power from the exhaust gas to drive the compressor. i would ideally like a...
  24. C

    Optimizing Compressor Efficiency: Small vs. Large Volume Gas Compression?

    for a given volume of gas,is it more efficient to compress smaller volumes of gas more no. of times or compress large volumes of gas less no. of times?
  25. A

    Why are spool systems and increased stages used in compressors for axial flow?

    why the spools(twin spool,triple spool) are used in compressors,why the stages in compressor must be increased
  26. A

    Cost of high capacity compressors ($/kW)

    Hello - I was looking at costs of compressors online and could find a couple of links that provided me $ for the power I was looking at. As the power increases, $/kW decreased. The range of kW that these websites could give me cost for was well below what I was looking at. Can someone help...
  27. RonL

    Scroll Compressors: Specs, Volume, Pressure & More

    After quite a bit of searching I have had little sucess finding specs or sources of buying just the scroll compressor head. Wiki and a few other sites have good animation that helped in the understanding of just how they work, and what makes them good for some applications. Most information has...
  28. J

    Achieving Sonic Flow with Shop Compressors and Vortex Tubes

    I am wondering if I can use a shop air compressor (120psi) to achieve sonic flow? I am building a vortex tube (for spot cooling) and need a high velocity jet to form the vortex. What is the minimum pressure diff. required to achieve sonic flow of compressed air? Does varying the diameter of the...
  29. M

    Refrigeration cycle with two compressors

    Homework Statement Here is the cycle: I am to assume cold-air standard applies. I need to: a)Draw a T-s diagram b)Find where heat is transferred and work is done c)Calculate the coefficient of performanceHomework Equations COP = 1 / (TH/TL - 1) The Attempt at a Solution For the T-s...
  30. K

    Exploring Projectile Motion with Compressors

    Homework Statement Hello everyone - here's my question: I am doing an assignment on projectile motion and I will be launching some balls from a compressor (that I have not seen yet!). I know how to calculate how much work will be done by the air expanding (will obv. depend on how much...
  31. C

    Why Do Gas Turbines and Compressors Have Specific Design Features?

    Dear All! I am in need of the follwing few questions regarding Gas Turbines and Compressors. It will be very nice and helpful if you people reply...an earliest reply will be appriciated why the flow channel in turbomachines usually does not have parallel hub and casing walls how the...
  32. C

    Fluid Machinery (Gas Turbines and Compressors)

    Dear All! I am in need of the follwing few questions regarding Gas Turbines and Compressors. It will be very nice and helpful if you people reply...an earliest reply will be appriciated why the flow channel in turbomachines usually does not have parallel hub and casing walls how the...
  33. F

    Reciprocating Compressors Energy Losses

    Hi, I was wondering if anybody could tell me what are the losses in a reciprocating compressor, and how would I calculate them. Specifically I'm interented to know how does the input energy (electrical) translate into output energy (pressure), and where would I look for the losses that may occur...
  34. S

    Where can I find information on overhead crane wheel derailment and maintenance?

    Why can't rotary vane compressors deliver high pressure ratios efficiently considering that the bending stress decreases as the vanes in the compressor slide down.
  35. M

    Selecting the Right Fuse Size for Compressors

    What do i have to take into consideration when deciding what fuze sizes are needed for the Medical Air Compressor, or generally any compressor. Compressors; cooling units, refrigerators, blowing units (cooling systems). Simply to say any compressor, any kind. Example; a brand new...
  36. C

    How Do Compressor Blades Exceed the Speed of Sound Without Loss of Performance?

    Ok, so a prop is an airfoil that spins and as such is subject to limitations that severly hamper performance as it approaches the speed of sound correct? But how do spinning compressor wheels like in a jet engine or a turbocharger not succumb to the same effects even when their blades would...
  37. T

    How does incoming air temperature affect peak boost in air compressors?

    ...I reposted this in general physics forum here. Tried to delete this one, but was denied access.
  38. S

    Pumps vs. Compressors: Understanding the Differences and Interchangeability

    pumps r compressors? a pump is used to increase the head of the fluid and a compressor is used to increase the pressure of the fluid...this pressure head is a form of energy and is transferable to other form [say increase in vertical height the fluid is raised] so can i use a pump and a...