Intelligent Compressed Air: Single Acting Reciprocating Air Compressors

Of all the types of air compressors on the market, you can’t beat the single acting reciprocating air compressor for simplicity:

Piston goes down: air is pulled in. Piston goes up: air is pushed out.

This simplicity is key to a couple of major advantages:

  • Price: they can cost 20-40% less than a similar rated (but more efficient) rotary screw model, up to about 5HP sizes.  This makes them great choices for home hobbyists and small industrial or commercial settings.
  • High pressure: It’s common to see reciprocating compressors that are capable of generating up to 3,000 psig.  Because the power is transmitted in the same direction as the fluid flow, they can handle the mechanical stresses necessary for this much better than other types of air compressors, which may need special modifications for that kind of performance.
  • Durability: out of necessity, their construction is very robust and rugged.  A good regimen of preventive maintenance will keep them running for a good, long time.  Speaking of which…
  • Maintenance (preventive): if you change your car’s oil and brake pads yourself, you have most of the know-how – and tools – to perform regular upkeep on a reciprocating air compressor.  There’s really not that much to them:

    The internals of a single acting reciprocating compressor.

Those advantages are buffered, though, by certain drawbacks:

  • Efficiency, part 1: The real work (compressing the air) only happens on the upstroke.  They’re less efficient than their dual acting counterparts, which compress on the downstroke too.
  • Efficiency, part 2: As size increases, efficiency decreases.  As stated above, smaller sizes usually cost appreciably less than more efficient (rotary screw, vane, centrifugal, etc.) types, but as you approach 25HP or higher, the cost difference just isn’t there, and the benefits of those other types start to weigh heavier in the decision.
  •  Maintenance (corrective):  Whereas they’re easy to maintain, if/when something does break, the parts (robust and rugged as they are) can get pretty pricey.
  • Noise: No way around it; these things are LOUD.  Most of the time, you’ll find them in a remote area of the facility, and/or in their own (usually sound-insulated) room.
  • High temperature:  When air is compressed, the temperature rises due to all the friction of those molecules getting shoved together…that’s going to happen with any air compressor.  All the metal moving parts in constant contact with each other, in a reciprocating model, add even more heat.
  • Oil in the air: If you’re moving a piston back & forth in a cylinder, you have to keep it lubed properly, which means you have oil adjacent to the air chamber.  Which means, no matter how well it’s built, you’re likely going to have oil IN the air chamber.

All that said, the benefits certainly do sell a good number of these compressors, quite often into situations where it just wouldn’t make sense to use any other type.  If you’re in the market for an air compressor,  you’ll want to find a local reputable air compressor dealer, and discuss your needs with them.  If those needs entail the use of engineered compressed air products, though, please feel free to give me a call to discuss.  We can make sure you’re going to ask your compressor folks the right questions.

Russ Bowman
Application Engineer
EXAIR Corporation
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Need to Cool Tooling but Limited On Compressed Air? Consider the Mini Cooler

I recently had a chat conversation with a customer who was looking to cool the tooling on his CNC router, mill and lathe in his small machine shop. During the machining process, as the tooling would begin to heat up, it would warp the bit, causing irregularities in the finished product. In some cases the tooling was getting so hot, it would actually break, creating a safety concern.

He had reviewed some of our cooling products and was thinking of using our Cold Gun in the application but was concerned with the air demand. The Cold Gun consumes 15 SCFM @ 100 PSIG and provides a 50°F temperature drop (from supply temperature) with 1,000 Btu/hr. of cooling capacity. The problem was that his compressor only produces a little over 9 SCFM. I explained that the existing compressor would in fact be undersized as it doesn’t produce enough volume to keep up with the demand of the Cold Gun.

Model 3808 Mini Cooler System with Single Point Hose Kit, includes swivel magnetic base and filter separator to remove moisture and particulate from the air supply.

Due to the limited amount of compressed air available, our Mini Cooler System, Model # 3808, would be the better solution. The Mini Cooler also provides a 50°F temperature drop with a little less cooling power, 550 Btu/hr., but this system only requires 8 SCFM @ 100 PSIG, falling within the existing compressor’s output capacity. The Mini Cooler also includes a magnetic base as well as flexible tubing to direct the cold air to the desired location, making it easy to move from machine to machine.

The Mini Cooler is the ideal solution for small tool or part cooling, with minimal air consumption.

If you are considering an EXAIR product for an application or have additional questions about performance, contact an application engineer for assistance in making the best selection.

Justin Nicholl
Application Engineer
justinnicholl@exair.com
@EXAIR_JN

 

 

 

Adding an Engineered Air Nozzle Prevents Buying a Larger Compressor

Atto Super Air Nozzle
Atto Super Air Nozzle

EXAIR products not only help large facilities in saving compressed air, but they also can help individuals.  I received a call from a happy customer that worked out of his garage.  He used a 5 horsepower compressor to blow off chips as his machine was cutting teeth into gears.  With his setup, he had an open copper pipe blowing continuously during the operation.  His air compressor would frequently cycle on and off, causing it to overheat and shut down.  Before purchasing a larger air compressor, he wanted to contact EXAIR to speak with the experts in saving compressed air.

I suggested the Atto Super Air Nozzle to be placed at the end of the pipe.  The first thing that he noticed was the power of the air stream.  The chips were being removed quickly, keeping the tool clean.  He also noticed that his small air compressor was only cycling on about 50% of the time instead of 90%.  This stopped the overheating issue.  He was so impressed that he contacted me to let me know how well this small mighty Super Air Nozzle worked.  He was able keep the gear teeth clean, and he did not have to purchase a larger air compressor.

It is nice when a customer is so impressed by the product that he has to contact you directly.  Whether your operation is big or small, you can save yourself money by adding EXAIR products to your operation.  If you would like to discuss further the benefits in using EXAIR products, you can contact one of our application engineers to help you.

 

John Ball
Application Engineer
Email: johnball@exair.com
Twitter: @EXAIR_jb