Any advice on rotary screw compressors?

5 HP Air Compressor with 80 Gallon Tank, Rotary Screw, Single Phase

This 5 HP Rotary Screw Air Compressor with 80 Gallon Tank will meet your most demanding applications. 10 Year Warranty on Rotary Screw Air Compressors.

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7.5 HP Quiet Air Compressor, Single Phase, 80 Gallon Tank, Vertical, Industrial

Eaton Compressor carries an impressive line of quiet air compressors, including this single phase 7.5 HP Quiet Air Compressor with 80 Gallon Tank.

NEW 7.5hp 2 Stage 1 Phase 80Gal Vertical Champion Air Compressor w/AFTER COOLER

We are currently experiencing a global parts shortage that is affecting the lead times of most air compressors. We have taken these units offline temporarily but we can still order them for you. Please contact us directly so we can give you an up-to-date status on the unit you are looking for...

The rotary screw compressors most are 3 phase, some are very finicky and require symmetrically balances 3 phase like the Kaeser compressors. In addition rotary screw compressors from what I have been told are made for continuous air demand, otherwise they will gum up with low load use. Piston air compressors the major source of noise is from the motor/air pump speed and the air intake noise. So you might look at the Eaton piston compressors Emax (Polar Air) in a 7.5Hp model which has a low speed motor/cast iron V4 compressor. With the high air output it also means it will have very fast recovery and on-time will be low. Alternative would be some form of sound enclosure or closet, but still need to have adequate ventilation to dissipate the heat. Eaton does make a 5Hp single phase rotary compressor, but almost 2X the price. If you have an option of an after cooler, I would recommend it to dropout the moisture before it hits the tank, and an automatic drain. The Eaton compressors also have one of the best warranties which is 5 years, but their piston compressor's are rated for 70% continuous use so light industrial. Probably the best bang for the buck in a quiet piston compressor that should last a long time. California Air does make a line of quiet air compressors, but they are more for light duty and they are oiless compressors which usually do not last more than hours if that. I would go with a slower turning piston compressor with a muffler on the intake and maybe some form of noise attenuation enclosure. Read the reviews.

Creating a compressed air system can be complicated. There are many factors to consider, including pipe width, amount and location of airdrops, placement of compressors, and specific brands that should be used for accessories like oil filters, hoses, and gauges. 

When planning a system, one of the most fundamental decisions is choosing between a piston compressor and a screw compressor. Each has its advantages; to make the right choice you need to understand costs, performance, maintenance, and more.

Let's briefly examine each type '.

Piston or reciprocating air compressors

Pistons or reciprocating compressors compress air by moving pistons that are driven by a crankshaft. Like a vehicle's engine, the pistons sit inside a cylinder. Essentially, when a piston compressor descends in the cylinder, it draws air into the compressor through an inlet. When the cylinder ascends, the air that was drawn in is pushed into the tank and gradually compressed or pressurized.

Screw air compressors 

Screw compressors use spiral screws inside a shaft that compresses air into a cylinder. They use two helical screws (a male and a female screw) that do not touch. Essentially, this style of compressor uses spiral screws to drive air into a container through a process known as 'positive displacement.' With this system, air travels through the machine and enters the tank where it is compressed and stored. 

The details of these machines are far more complicated, but this is a basic summary of the working principles for piston vs screw compressors. 

Factors to consider when making a choice

Here are a few items to consider when deciding whether you want a piston or screw air compressor.

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Initial and long-term costs

Piston compressors are more affordable initially. While the exact price difference will vary, and you can certainly find piston compressors that are more expensive than some screw compressors, in general, you'll spend more when purchasing a screw compressor.

However, there can be higher long-term costs for piston compressors that typically aren't needed for screw compressors. Screw compressors save on energy and maintenance costs. Piston compressors tend to use more power and require more attention over the longer term. 

Service and repairs

Included in long-term costs are your service contracts. Screw compressors require a larger initial investment, but these compressors have fewer moving parts. While nothing is certain, and they can break down, screw compressors generally need less service and maintenance.

Repairs and maintenance cost money, but can also disrupt operations, impacting your company's productivity and profitability. So, it's not just your investment in maintenance, it's the ability to keep production up and running.

Noise

Piston compressors are loud. Loud compressors can be costly.

Look at this video from Kaeser, one of the top compressor manufacturers in the world. They performed a test that compared the noise levels of piston and screw compressors. Using the same measuring device at the same distance, they found that a 5-hp piston compressor put out 83 dB-A of sound, while a 5-hp screw compressor was only at 68 dB-A. 

Obviously, the louder a compressor, the more hearing protection is needed. As OSHA requires levels to be under 85 decibels to prevent hearing loss, a piston compressor is already dangerously close to the permitted noise-level limit. Violating OSHA guidelines may involve fines. That cost doesn't include damage to your workforce and worker's compensation claims.

Hearing protection can always dampen the sound, and should be used, but may not be enough to take the noise to safe levels depending on what's running your facility or plant.

Space requirements

Screw compressors can be smaller for a variety of reasons. Piston compressors need larger storage tanks because of their duty cycle, taking up more room. Essentially, they have limits in duty cycles, which means they must store more air to meet the needs of high-demand operations. 

Bottom line: large-scale operations benefit from screw compressors

There are other factors to consider (if you have more questions, contact our team), but these are the most important issues that will impact your decision. Overall, piston compressors are an affordable, reliable choice for small operations or businesses that have a limited need for air compression, but don't require compressed air on a large scale. 

However, companies with a continuous need for large-scale compressed air will prefer a screw compressor. With lower long-term energy and maintenance costs, and the ability to continually provide uninterrupted air, screw compressors are preferred by most manufacturers. 

We carry a wide range of piston and screw compressors and can provide ideas and quotes. Talk to our team and get some suggestions about the type of compressed air system we recommend.

If you want to learn more, please visit our website High Pressure Screw Air Compressor.