Find It, Tag It, Fix It: Addressing Parasitic Draw

Leeks, and not the compressed air kind!

Leaks, and not the kind you see on a cooking show, are never good. Before you comment, yes I know the vegetable is spelled leek, that’s just the strength of my dad jokes. The point of this post is actually discussing leaks, mainly of the compressed air variety. All leaks cost. I recently found a leak within my home which was accounting for around a 20% increase in my water bill. Sad to say that it took a few months to locate, and solve the issue. Over the years, I’ve seen many facilities deal with common leak problems like being unable to leave their compressed air pipes energized over night because the parasitic draw will drain the entire system. That’s a problem!

Burst pipes and leaks are ALWAYS costly!

If the leaks are present when nothing is being utilized, then that means parasitic draw is happening on the system. This is when energy that is being converted into compressed air isn’t used but instead, leaking out to atmospheric conditions. These parasitic draws are not always easy to locate, so over the years I’ve had to help a few customers address this problem. One in particular stands out, so I am going to share how we honed in on the leak and ultimately gave them days without a shutdown.

The conversation all started with a customer asking about how our Digital Flowmeters work, and if they could be used to determine which production line is using the most air, and more importantly why their production line shuts down for low air pressure. After I explained how we would select their infeed pipe size as well as size a meter that would fit each machine infeed, we got to talking about the shut down sequence.

The approach they took to solving the issue was to first capture the flowrate of the entire system and then to evaluate the flowrates of each segment of their plant. From there, we would install flowmeters on the higher usage sectors, and drill down to each machine for the finite analysis. They could then go through all the other production lines and generate a full facility consumption profile. To start, they found one packaging line that was using a considerably higher volume of air throughout their first shift than any other line and than any other shift.

Once they started breaking down the high demand production line they found one leg of the production line which had a spike in usage at the same time every day. The trick was they couldn’t find a machine with high usage, that is until they traced all of the piping and found a filter bag house on the roof that had been added to the line at some point. This wasn’t documented and had a piece of pipe that had failed causing an open dump during the cleaning cycle every day at 2:30 in the afternoon.

This was all made possible by setting up multiple flowmeters with wireless capabilities so they could document and compare the usages between machines and production lines ultimately giving them a considerable amount of production time back into the day by fixing a broken pipe that caused daily shutdowns.

If you would like to discuss how to layout a compressed air monitoring system in your facility or the best way to track down the cause of some leaks and high compressed air demand, contact an Application Engineer.

Brian Farno
Application Engineer
BrianFarno@EXAIR.com
@EXAIR_BF

1 – Leeks on shelf – Jeffery Martin, CC0, via Wikimedia Commons – retrieved from – https://commons.wikimedia.org/wiki/user:Veronicasgardentracker

About Rotary Screw Air Compressors

What is an air compressor? In simple terms it is a machine that increases fluid pressure, it works by changing the volume of air and storing it in a storage tank. Many industries use compressors to increase production and thus has led to the development of many new industries. There are a couple types of air compressors but today I will focus on the Rotary Compressor.

The Rotary Screw Compressor is a very common type of air compressor. This compressor uses dual rotors with meshing lobes that trap air while rotating. The rotation continues to push air toward a discharge port while decreasing the space the air take sup, thus increasing pressure. The rotary compressor has a simple structure with few components and has some clear advantages over other compressors:

  • Longevity
  • When operating, they are quiet
  • Low vibration
  • Continuous operation, or they can match demand

Some disadvantages include:

  • Skilled maintenance required compared to other compressors.
  • They are more expensive than other compressors

There are two types of rotary air compressors. They are oil-injected and oil-free rotary air compressors. Oil-injected rotary screw compressors as the name suggests has oil injected in the compressor element during the air compression. An insignificant amount of oil will escape into the compressed air system also known as “oil carryover”. The use of EXAIRs oil removing filters and filter separators will help remove the oil, moisture and other particulates from the compressed air lines resulting in clean compressed air.

Oil-free rotary screw compressors are similar to the oil-injected compressor but without the use of oil. The oil-free compressors use a two stage system with a cooling process between stages as the compressed air will become extremely hot if not for a cooling process between stages of compression. The oil-free compressors are commonly used in food and medical industries.

EXAIR is here to help with your “Intelligent Compressed Air Products” so please contact us with your compressed air tooling needs.

Eric Kuhnash
Application Engineer
E-mail: EricKuhnash@EXAIR.com
Twitter: @EXAIR_EK

File:IngersollRand R-series-R110.jpg image is licensed under the Creative Commons Attribution 3.0 License.

Methods, Patterns, and Continuous Improvement

I’ve blogged about the fact that I am married to an amazing woman and we have been blessed with three incredible daughters before. My wife and I are constantly being reminded of just how different raising kids in this digital and rapidly changing world is compared to when we were kids. And, just writing those statements makes me realize I have truly entered the next (I’m old) chapter of my life.

My oldest, who is 12, is at that point where she is gaining some independence at middle school, and at the same time is getting sucked into social norms where she can easily be consumed by social media and screen time. The challenge I took on was to find something analog that we could both pick up and enjoy, maybe even challenge each other with. Enter a classic that I was never able to master, and still can’t without the aid of another (my 12 year old), the Rubik’s Cube. I was honestly shocked when she took the time to review a video from our library and learned the patterns to solve the cube. Turns out a few of her friends are even able to solve them and thus the education began.

A traditional 3×3 Speed Cube in a solved state then converted to a checkerboard pattern.

What I once thought was an impossible task was broken down into patterns and a logical path to correct and straighten out the tangled squares. The are a number of methods to solve the standard 3×3 cube. No matter what, the pattern has to be recognized, implement the steps to solve, and then improve through repetition. Not many people pick something like this up, solve it once and then sit it down. It becomes a process of continuous improvement and that is exactly what my daughter took on. For me, it reminded me of Lean Manufacturing and every process I have ever looked at professionally. It was truly rejuvenating for me to see her take on the challenge and then have an urge to improve her process time.

When I came into work the next day, it clicked. That same process of methodical movements could all connect to our Six Steps to Compressed Air Optimization. Each of these steps is solving another layer of a mixed up cube. While at first, the process of optimizing a compressed air system can easily seem out of reach it is easily broken down into steps that result in a solution. Then, instead of taking all of that new found knowledge to only conduct the six steps once, you can easily make this a recurring event. Because even though your facility may not change, the air system will, new leaks may appear, items on the supply side may wear, demand side application may change as processes are added or modified.

Processes lead to continuous improvement.

Continuous improvement is a method that propels a system forward toward efficiency and improved outcomes and it is something that is needed to stay relevant. Even with the methods of solving a 3×3 cube, those methods continue to evolve and the main level of improvement is often on the person spending time with the process. If you want to discuss a compressed air application in your facility that could stand some improving or maybe you want to share your solve times on the 3×3 cube, don’t hesitate to reach out to me.

Brian Farno
Application Engineer
BrianFarno@EXAIR.com
@EXAIR_BF

A-Z of Compressed Air Systems & Maintenance

To fully appreciate how impactful a properly functioning air compressor system is to your bottom line, it is foremost important to fully understand how much your compressed air costs. Compressed air is a self generated utility within your facility that is a top 3-4 utility expense for your company. This fact is often overlooked or misunderstood, because the expense is primarily linked to the electric and or gas bill. This can be a costly oversite. You will see an example below where a single common maintenance issue causes a 4psi reduction in performance and resulted in $1265 in additional annual cost to that company. Imagine when/if there are multiple issues…

In order to calculate the compressed air cost, some companies use an educated guess of @$0.25 per 1000 cubic feet of compressed air consumed, and others are more precise. The U.S. department of Energy performed an energy saving study in 2004 and they show a precise way to calculate your compressed air cost. Here is their sample calculation:

“Compressed air is one of the most expensive sources of energy in a plant. The overall efficiency of a typical compressed air system can be as low as 10%-15%. For example, to operate a 1-horsepower (hp) air motor at 100 pounds per square inch gauge (psig), approximately 7-8 hp of electrical power is supplied to the air compressor. To calculate the cost of compressed air in your facility, use the formula shown below:

Cost ($) = (bhp) x (0.746) x (# of operating hours) x ($/kWh) x (% time) x (% full-load bhp) ÷ Motor Efficiency
Where:
bhp = Motor full-load horsepower (frequently higher than the motor nameplate horsepower—check equipment specification)
0.746 = conversion between hp and kW
Percent time = percentage of time running at this operating level
Percent full-load bhp = bhp as percentage of full-load bhp at this operating level
Motor efficiency = motor efficiency at this operating level
Example:
A typical manufacturing facility has a 200-hp compressor (which requires 215 bhp) that operates for 6800 hours annually. It is fully loaded 85% of the time (motor efficiency = .95) and unloaded the rest of the time (25% full-load bhp and motor efficiency = .90). The aggregate electric rate is 0.05/kWh.
Cost when fully loaded =
(215 bhp) x (0.746) x (6800 hrs) x ($0.05/kWh) x (0.85) x (1.0) = $48,792
.95
Cost when unloaded =
(215 bhp) x (0.746) x (6800 hrs) x ($0.05/kWh) x (0.15) x (0.25) = $2,272
.90
Annual energy cost = $48,792 + $2,272 = $51,064″

Pic courtesy of Gunjan2021 Pixaby License

I encourage you to calculate this self generated utility cost for your facility. Also keep in mind that this example is using $0.05/kWh, this example was form 2004, today the average industrial sector cost in the US is $0.0747 (see more here). This annual cost puts so many things into perspective. First and foremost the importance of Maintenance. Even more specific, the preventative maintenance costs become much lower than the impact of even one small oversite. Here is an example from the Department of Energy that discusses a specific and common maintenance issue and it’s annual impact.

“A compressed air system that is served by a 100-horsepower (hp) compressor operating continuously at a cost of $0.08/kWh has annual energy costs of $63,232. With a dirty coalescing filter (not changed at regular intervals), the pressure drop across the filter could increase to as much as 6 psi, vs. 2 psi when clean. The pressure drop of 4 psi accounts for 2% of the system’s annual compressed air energy costs. (or an increase of $1,265 per year)”

The realization of the dollars spent for compressed air certainly pushes the priority of maintenance. If we extrapolate from the above filter example, we can see that a 4 psi pressure drop in that system increased the cost by $1265 per year. We need to then ask ourselves, what other areas could be causing a pressure drop or stressing the motor? And if there is an issue upstream to this issue, will it cause even more issues, or more pressure drops?

There are many tips, tools, websites, YouTube videos and more, out there that address the recommended maintenance of your compressor and system. Many of you already have specific guidelines for your precise system, and set maintenance schedules in place. Below is a sample checklist (not all-inclusive) of maintenance items to watch for with your compressor in case you need a starting point. If left unchecked and or uncorrected, any of these (if an issue) will cost your company money – over time, lots of money.

  • Visually Inspect Air Compressor
  • Check moisture traps
  • Change Air Filters
  • Change Oil Filters
  • Change Oil/Water Separators – could (should) be many of these on the lines
  • Change Oil Separator O-Ring if necessary
  • Inspect Couplers, Hubs and Shaft Seals
  • Check Drive Belts condition if applicable
  • Check and Log Drive Motor Bearing Temps
  • Check and Log Fan Motor Bearing Temps
  • Change Oil if necessary
  • Check and Log Oil Cooler Temps
  • Check and Log After Cooler Temps
  • Blow Out Coolers

I would be amiss if I finished this blog without mentioning the perils of pressure leaks. The Compressed Air and Gas Institute stated that a single 1/4″ leak, can cost you between $2500 and $8000 per year (CAGI article). Imagine the impact of several leaks!!!

How do I find leaks? I’m glad you asked. The first step is to walk your lines and check any or all of the following areas for leaks or damage.

  • Couplings
  • Hoses
  • Tubes
  • Fittings
  • Point-Of-Use Devices
  • Pipe Joints
  • Quick Disconnects
  • Filters
  • Regulators
  • Lubricators
  • Condensate Traps
  • Valves

A great way to identify leaks is to use our Ultrasonic Leak Detector to listen for leaks. Look for and ask the technicians if there seems to be a change in productivity. Install Pressure Regulators and gauges at each point of use in your facility – monitor and log these pressures often. Once you find an issue, no matter how small, correct it. A small leak adds up $$$ over the hours, weeks, and months.

In addition to leaks, there are many times that air is wasted by being blown on empty space (i.e. the space between items on your conveyor). you, please look at our Electronic Flow Control (EFC) product, this device gives you an out of the box automation solution that can be set up in minutes and save thousands. There are so many clogged and leaking pipes, bad hoses inside many plants, this coupled with using an poor performing Air Gun, or Air Nozzle all have large dollar impacts for your company. EXAIR has products that can help in all of these areas…

In parting, please keep in mind that many Utility companies offer incentives to companies that take an initiative to reduce their energy footprint. In our current time of inflation this is a real way to reduce costs, many times significantly. We are here to help. Please contact us for assistance in dramatically reducing both your utility costs, and your environmental impact.

Pic courtesy of PIRO4D Pixaby License

Thank you for stopping by. Please reach out if you have any questions about this Blog, or any of EXAIR’s amazing products.

Brian Wages
Application Engineer
E-mail: BrianWages@EXAIR.com
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