What Size Air Compressor You Need for Industrial Use

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How to determine What Size Air Compressor You Need for Industrial Use

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Kaishan USA | October 31, 2022 | Uncategorized

How to Determine What Size Air Compressor You Need for Industrial Use

You would think that it would be relatively easy to size an air compressor. Just add up the CFM you need, and you have the capacity you need for your plant. Done and done.

The answer, unfortunately, is not so fast.

Sizing an industrial air compressor for maximum efficiency requires that you balance a variety of factors: CFM, of course, but also demand profiles, pressures, applications, plant layout, and other equipment like storage, dryers, and piping.

Let’s walk through the process.

Start with Flow

The conventional wisdom, of course, is partially correct. You do start by adding up the cubic feet per minute (CFM) that you’ll require for the applications that need compressed air. Recognizing that the requirements might vary from application to application.

And your compressor CFM should be based on average use as well as peaks and low-demand periods. That will allow you to determine the most efficient and flexible system.

An industrial painting facility, for instance, might have a sandblasting application that they only operate for an hour a day or a few hours a week, or even a few hours a month.

Most people will size their air system to accommodate the needs of that sandblaster, which takes up 90% of their air use. But only when it’s in operation.

They’ll say, “I need 100 HP for my sandblaster. So I'll buy 150 HP, so I've got plenty of air.”

That means, though, that they're running at about 10% capacity on their air compressor the rest of the time, which is extremely inefficient and will create other problems.

So that means you’ll need to consider your demand profile – are you running three shifts a day, all with equal demand for air pressure? Most likely, you’re not.

If you’re like most companies, you doing two solid shifts and a skeleton crew on the third. If your compressor is designed to meet the needs of those two main shifts, it’s going to be very costly to run that machine at night.

And the stakes are high: if you’re running your air compressor at the same level on all three shifts, your energy expenses will exceed the price of the machine in the first six months.

But that is by no means the end of the story. For instance, you’ll want to consider use of multiple, smaller units, making your system more efficient and reliable. More on this topic later.

Next, you’ll also need to consider pressure, commonly referred to as PSIG.

Pressure Requirements

Each application needs different pressure, measured as pounds per square inch (psi). For example, most tools and lifts require 90 to 100 psi, with the largest users being dust filtration and bag houses.

So, typically, most people plan a system based on the highest pressure required. If you have one particular application that requires a high pressure, say 125 psi, then you can add some efficiency by isolating this application and servicing it with a booster or a compressor dedicated to this high pressure application.

But the relationship between the two is a little more complicated than that.

Let’s take the example of a large application like blasting that requires a lot of pressure, often in peaks of 100 psi or more.

They'll need to put regulators on their other equipment to ensure they're scaling down to the proper pressure for each application. But that often means there’s a lot of wasted energy to get to higher pressures.

And someone who doesn’t know what they’re doing inevitably opens those valves. If the regulator is at 50 pounds and they unscrew it, you're losing 100 pounds. That ultimately wastes a dramatic amount of compressor air (and money!).

Plus, that extra pressure can damage some of your equipment.

The point is that they don't need 150 HP capacity for their plant. They should have 100 HP for that blaster and 10 HP for the rest of their plant. That's it.

But a lot depends on the various applications you will serve with your air compression system.

Applications

As mentioned earlier, specific applications like dust filtration, bag houses, blasting, bulk conveying, and materials handling have specific requirements.

Paint spray tools that must draw sufficient pressure to atomize paint for an even, consistent coat.

Certain pneumatics don't need that much pressure to operate on machinery, but they need more volume to keep the pressure stable.

As a result, needs can swing dramatically, especially when you are using specific pieces of equipment. And it may vary across shifts, especially when you have 100 people on the first shift and only 30 people on the second shift. That usually correlates to a dramatic drop in air demand.

A related consideration is the site condition. Is the location for the compressor inside or outside? Will there be a lot of dust, dirt, and gravel coming in? Will it be exposed to cold? Admittedly, air compressors are rugged, but you’ll want to know site conditions going in. And you’ll want to plan for them.

You'll want to consider all that when you're planning your system.

Other Equipment

Compressed air systems all need to remove moisture that inevitably enters your system. If not removed, water creates downstream issues, from contamination of end products to damaging pneumatic machinery and other components.

Air compressor dryers help remove that moisture, protecting your system and products.

Compressed air filters remove particulates that enter your compressor’s intake, regardless of the air source.

In addition, some facilities rely on storage tanks to build up a supply of compressed air, ensuring uninterrupted supply, even during peak usage. As a result, some compressors come equipped with compressed air tanks. Typically, we recommend three to five gallons of air storage capacity per air compressor CFM output for most applications.

Compressed air moves through your plant through pipes, usually made of metal. Black steel (usually marked blue with white lettering, according to ANSI/ASME standards is the traditional material in compressed air systems because it is readily available. So durable and strong many fitters can install it. But it produces rust contamination, which could damage sensitive pneumatics tooling.

Other metal options include galvanized steel, stainless steel, aluminum, and copper, each of which has unique advantages.

That leads to the next consideration: the layout of the plant.

Plan Layout

Unfortunately, pressure is lost as air is transmitted through long runs of piping through the plant and goes through filters and dryers.

Is your plant layout optimized for industrial air compressor usage

And there are other problems as well, including:

- Angles or sharp turns will slow down the airflow, reducing pressure as well. Bends in a pipe cause air to ricochet off the pipe’s interior, wasting energy and creating what engineers call “turbulent flow,” leading to a pressure drop. Therefore, avoid sharp bends and aim for gentler ones ranging from 30 to 45 degrees. The overall goal is “laminar flow,” which is smooth and streamlined.
- Water corrodes certain kinds of metal pipes. Ultimately, this corrosion will create rust flakes that travel through the piping system, eventually reaching end-use equipment, clogging nozzles, and contaminating products or finished materials. In addition, rust formation makes a pipe’s interior surface rough, causing turbulence that further reduces air pressure.
- Obstructions. The rust and corrosion mentioned above can flake off and accumulate in connectors, valves, sensors, or dryers, restricting airflow, lowering the pressure upstream, and backing up the pressure upstream. The good news? Blockages quickly become known, causing excess pressure in front of them and lower pressure after them.

As mentioned earlier, most tools and lifts require 90 psi of pressure. And pneumatic equipment – like pumps, valves, motors, and tools – generally requires 80 to 90. So that's how many plant operators come up with the 100- or 125-pound figures for air compressors. And the reason why 125-pound compressors got so popular.

Typically, a 100 psi compressor is all you need if you plan out the air usage correctly.

But most systems are not laid out optimally. And the pressure can get low at the far reaches of your system.

You could, for instance, have 115 psi coming out of your air compressor. But, at the end of the line, there's a guy saying, “Hey, I'm only getting 80 pounds. I need more pressure.”

The typical response is to dial up the pressure on their compressor.

But that may backfire. By dialing up the pressure, you may have more leaks and waste more air throughout the piping system, wasting energy. And delivering less pressure, even though you dialed up the pressure at the machine.

The solution, as a result, may involve a different configuration of your air compressor system – deploying multiple smaller compressors strategically placed throughout your plant. Or even portable air compressors that are mobile, able to be moved from one application to another.

But that requires taking a broader view of your compressed air needs.

The solution? An air audit by a trained professional.

Air Audits

We've always been a big fan of doing air audits, especially when there are a lot of questions in the air – or answers that don't inspire confidence.

It takes just a few minutes and requires installing data logging equipment at key points in your system to capture pressure and flow measurements. That data is then analyzed.

An air audit can help you lay out the system and determine what size air compressor you need. And it may indicate a rethinking of your approach. So rather than have one large air compressor providing compressed air to your entire plant, you have several smaller machines deployed throughout your plant to meet the needs of individual processes.

The original cost may be lower, but the system will have a payback as short as two years due to energy savings and reduced maintenance requirements. After all, energy makes up 70% of the lifecycle cost of a compressor, dwarfing initial cost, installation, and maintenance.

Air audits can help you configure your system to optimize energy consumption, improve compressor efficiency, reduce maintenance, cut downtime, and lower your total cost of ownership (TCO).

As noted, determining what size air compressor you need is a little more involved than it might seem at first blush. But it doesn't have to be complicated. And we can help you figure out what you need. Reach out to the experts and contact us today.

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Air compressors are used for a broad range of applications in the mining industry, providing a reliable source of power ideally suited for the extended use, harsh environments and safety requirements needed for successful operation in this area.

How to Determine What Size Air Compressor You Need for Industrial Use

Kaishan USA Announces New Website

Reduce Energy Costs: Four Tips for Plant Managers

How to determine What Size Air Compressor You Need for Industrial Use

Start with Flow

Pressure Requirements

Applications

Other Equipment

Plan Layout

Air Audits

Random stat orcustomer quote

textXXtext

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