How to Manage Condensate in Your Compressed Air System

If you operate an air compressor, you’re drawing water vapor into your compressed air system.  Factors like climate control (or lack thereof,) and humidity will dictate how much.  If (or more to the point, when) it condenses, it becomes an issue that must be addressed.  There are several types of dryer systems to choose from, usually when you buy your compressor…we’ve covered those in a number of blogs.  Some of these can leave a little more water vapor than others, but remain popular and effective, when considering the cost, and cost of operation, of the different types.

So, how do you handle the condensate that the dryer doesn’t remove?

  • Receivers, or storage tanks (like EXAIR Model 9500-60, shown to the right,) are commonly used for several reasons:
    • By providing an intermediate storage of compressed air close to the point of use, fluctuations across the system won’t adversely affect an application that needs a constant flow and pressure.
    • This also can keep the air compressor from cycling rapidly, which leads to wear & tear, and additional maintenance headaches.
    • When fitted with a condensate drain (more on those in a minute,) they can serve as a wet receiver.  Condensate collects in the bottom and is manually, or automatically emptied.
  • Condensate drains, while popularly installed on receivers, are oftentimes found throughout larger systems where the vapor is prone to condense (intercoolers, aftercoolers, filters and dryers) and where the condensation can be particularly problematic (drip legs or adjacent to points of use.) There are a couple of options to choose from, each with their own pros & cons:
    • Manual drains are self explanatory: they’re ball valves; cycled periodically by operators.  Pros: cheap & simple.  Cons: easy to blow down too often or for too long, which wastes compressed air.  It’s also just as easy to blow down not often enough, or not long enough, which doesn’t solve the condensate problem.
    • Timer drains are self explanatory too: they cycle when the timer tells them to. Pros: still fairly cheap, and no attention is required.  Cons: they’re going to open periodically (per the timer setting) whether there’s condensate or not.
    • Demand, or “zero loss” drains collect condensate until their reservoir is full, then they discharge the water.  Pros: “zero loss” means just that…they only actuate when condensate is present, and they stop before any compressed air gets out.  Cons: higher purchase price, more moving parts equals potential maintenance concerns.
  • The “last line of defense” (literally) is point-of-use condensate removal.  This is done with products like EXAIR Automatic Drain Filter Separators.  They’re installed close to compressed air operated devices & products, oftentimes just upstream of the pressure regulator and/or flow controls…the particulate filter protects against debris in these devices, and the centrifugal element “spins” any last remaining moisture from the compressed air flow before it gets used.
Good engineering practice calls for point of use filtration and moisture removal, such as that provided by EXAIR Filter Separators.

Efficient and safe use of your compressed air includes maintaining the quality of your compressed air.  If you’d like to find out more about how EXAIR Corporation can help you get the most out of your compressed air system, give me a call.

Russ Bowman
Application Engineer
EXAIR Corporation
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Compressed Air Efficiency – How It Benefits Business

It is estimated that typically plants can waste up to 30 percent of their generated compressed air and that cost is substantial.  Considering the average cost to generate compressed air here in the Midwest is .25 cents per 1,000 Standard Cubic Feet, that translates into .075 cents for every .25 cents spent!  Compounded with the fact that energy costs have doubled in the last five years, it couldn’t be a better time to make your air compressor system more efficient.

efficiencylab

The following steps will help you save air and in turn save money.

  1. Measure the air consumption to find sources that use a lot of compressed air.

Knowing where you stand with your compressed air demand is important to be able to quantify the savings once you begin to implement a compressed air optimization program. Placing a value upon your compressed air consumption will also allow you to place a value on its costs and the savings you will reap once you start to reduce your consumption. (EXAIR’s Digital Flow Meter)

9093ZG-DG

  1. Find and fix the leaks in your compressed air system.

Not fixing your compressed air system leaks can cause your system pressure to fluctuate and affect your equipment negatively. It may cause you to run a larger compressor than necessary for your compressed air needs and raise your total costs. Or it could cause your cycle and run times to increase which leads to increased maintenance to the entire system. (EXAIR’s Ultrasonic Leak Detector)

uhd kk

  1. Upgrade your blow off, cooling and drying operations using engineered compressed air products.

Your ordinary nozzle with a through hole and a cross drilled hole can be an easy choice based upon price, but if you do not consider the operating cost you do not really know how much it is costing you. An Engineered Air Nozzle will pay for itself and lower operating costs quickly. Engineered Air Nozzles are the future of compressed air efficiency and are made to replace ordinary nozzles, homemade nozzles and open line blow offs. Engineered Nozzles reduce air consumption and noise levels; ordinary nozzles cannot compete. Engineered Nozzles maintain safety features and can qualify for an energy savings rebate from a local utility; ordinary nozzles fall short. Open blow off or homemade blow off applications typically violate OSHA safety standards; Engineered Nozzles do not.  (EXAIR’s Air Nozzles)

nozzlescascade2016cat29_559
EXAIR Nozzles
  1. Turn off the compressed air when it is not in use.

Automated solutions add solenoid valves and run them from your machine controls. If the machine is off, or the conveyor has stopped – close the solenoid valve and save the air.  And blow off applications can benefit from any space in between parts by turning the air off during the gaps with the aid of a sensor and solenoid. (EXAIR’s automated  Electronic Flow Control)

 

  1. Use intermediate storage of compressed air near the point of use.

Also known as secondary receivers, intermediate air storage is especially effective when a system has shifting demands or large volume use in a specific area. Intermediate storage is the buffer between a large demand event and the output of your compressor. The buffer created by intermediate storage (secondary receiver) prevents pressure fluctuations which may impact other end use operations and affect your end product quality. (EXAIR’s Receiver Tanks)

  1. Control the air pressure at the point of use to minimize air consumption.

This is a very simple and easy process, all it requires is a pressure regulator. Installing a pressure regulator at all of your point of use applications will allow you to lower the pressure of these applications to the lowest pressure possible for success. Lowering the pressure of the application also lowers the air consumption. And it naturally follows that lower air consumption equals energy savings. (EXAIR’s Pressure Regulators)

By increasing your awareness of the health of your air compressor system and implementing a PM program you can significantly reduce your costs from wasted energy and avoid costly down time from an out of service air compressor.

If you would like to discuss improving your compressed air efficiency or any of EXAIR’s engineered solutions, I would enjoy hearing from you…give me a call.

Jordan Shouse
Application Engineer
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How to Size a Receiver Tank and Improve your Compressed Air System

Receiver Tank: Model 9500-60

My colleague, Lee Evans, wrote a blog about calculating the size of primary receiver tanks within a compressed air system.  (You can read it here: Receiver Tank Principle and Calculations).  I would like to expand a bit more about secondary receiver tanks.  They can be strategically placed throughout the plant to improve your compressed air system.  The primary receiver tanks help to protect the supply side when demands are high, and the secondary receiver tanks help systems on the demand side to optimize performance.

Circuit Board

I like to compare the pneumatic system to an electrical system.  The receiver tanks are like capacitors.  They store energy produced by an air compressor like a capacitor stores energy from an electrical source.  If you have ever seen an electrical circuit board, you notice many capacitors with different sizes throughout the circuit board (reference photo above).  The reason is to have a ready source of energy to increase efficiency and speed for the ebbs and flows of electrical signals.  The same can be said for the secondary receiver tanks in a pneumatic system.

To tie this to a compressed air system, if you have an area that requires a high volume of compressed air intermittently, a secondary receiver tank would benefit this system.  There are valves, cylinders, actuators, and pneumatic controls which turn on and off.  And in most situations, very quickly.  To maximize speed and efficiency, it is important to have a ready source of air nearby to supply the necessary amount quickly.

For calculating a minimum volume size for your secondary receiver tank, we can use Equation 1 below.  It is the same as sizing a primary receiver tank, but the scalars are slightly different.  The secondary receivers are located to run a certain machine or area.  The supply line to this tank will typically come from a header pipe that supplies the entire facility.  Generally, it is smaller in diameter; so, we have to look at the air supply that it can feed into the tank.  For example, a 1” NPT Schedule 40 Pipe at 100 PSIG can supply a maximum of 150 SCFM of air flow.  This value is used for Cap below.  C is the largest air demand for the machine or targeted area that will be using the tank.  If the C value is less than the Cap value, then a secondary tank is not needed.  If the Cap is below the C value, then we can calculate the smallest volume that would be needed.  The other value is the minimum tank pressure.  In most cases, a regulator is used to set the air pressure for the machine or area.  If the specification is 80 PSIG, then you would use this value as P2.  P1 is the header pressure that will be coming into the secondary tank.  With this collection of information, you can use Equation 1 to calculate the minimum tank volume.  So, any larger volume would fit the requirement as a secondary receiver tank.

Secondary Receiver tank capacity formula (Equation 1)

V = T * (C – Cap) * (Pa) / (P1-P2)

Where:

V – Volume of receiver tank (cubic feet)

T – Time interval (minutes)

C – Air demand for system (cubic feet per minute)

Cap – Supply value of inlet pipe (cubic feet per minute)

Pa – Absolute atmospheric pressure (PSIA)

P1 – Header Pressure (PSIG)

P2 – Regulated Pressure (PSIG)

If you find that your pneumatic devices are lacking in performance because the air pressure seems to drop during operation, you may need to add a secondary receiver to that system.  For any intermittent design, the tank can store that energy like a capacitor to optimize the performance.  EXAIR stocks 60 Gallon tanks, model 9500-60 to add to those specific locations, If you have any questions about using a receiver tank in your application, primary or secondary, you can contact an EXAIR Application Engineer.  We can restore that efficiency and speed back into your application.

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

 

Photo: Circuit Board courtesy from T_Tide under Pixabay License

Opportunities To Save On Compressed Air

If you’re a regular reader of the EXAIR blog, you’re likely familiar with our:

EXAIR Six Steps To Optimizing Your Compressed Air System

This guideline is as comprehensive as you want it to be.  It’s been applied, in small & large facilities, as the framework for a formal set of procedures, followed in order, with the goal of large scale reductions in the costs associated with the operation of compressed air systems…and it works like a charm.  Others have “stepped” in and out, knowing already where some of their larger problems were – if you can actually hear or see evidence of leaks, your first step doesn’t necessarily have to be the installation of a Digital Flowmeter.

Here are some ways you may be able to “step” in and out to realize opportunities for savings on your use of compressed air:

  • Power:  I’m not saying you need to run out & buy a new compressor, but if yours is

    Recent advances have made significant improvements in efficiency.

    aging, requires more frequent maintenance, doesn’t have any particular energy efficiency ratings, etc…you might need to run out & buy a new compressor.  Or at least consult with a reputable air compressor dealer about power consumption.  You might not need to replace the whole compressor system if it can be retrofitted with more efficient controls.

  • Pressure: Not every use of your compressed air requires full header pressure.  In fact, sometimes it’s downright detrimental for the pressure to be too high.  Depending on the layout of your compressed air supply lines, your header pressure may be set a little higher than the load with the highest required pressure, and that’s OK.  If it’s significantly higher, intermediate storage (like EXAIR’s Model 9500-60 Receiver Tank, shown on the right) may be worth looking into.  Keep in mind, every 2psi increase in your header pressure means a 1% increase (approximately) in electric cost for your compressor operation.  Higher than needed pressures also increase wear and tear on pneumatic tools, and increase the chances of leaks developing.
  • Consumption:  Much like newer technologies in compressor design contribute to higher efficiency & lower electric power consumption, engineered compressed air products will use much less air than other methods.  A 1/4″ copper tube is more than capable of blowing chips & debris away from a machine tool chuck, but it’s going to use as much as 33 SCFM.  A Model 1100 Super Air Nozzle (shown on the right) can do the same job and use only 14 SCFM.  This one was installed directly on to the end of the copper tube, quickly and easily, with a compression fitting.
  • Leaks: These are part of your consumption, whether you like it or not.  And you shouldn’t like it, because they’re not doing anything for you, AND they’re costing you money.  Fix all the leaks you can…and you can fix them all.  Our Model 9061 Ultrasonic Leak Detector (right) can be critical to your efforts in finding these leaks, wherever they may be.
  • Pressure, part 2: Not every use of your compressed air requires full header pressure (seems I’ve heard that before?)  Controlling the pressure required for individual applications, at the point of use, keeps your header pressure where it needs to be.  All EXAIR Intelligent Compressed Air Product Kits come with a Pressure Regulator (like the one shown on the right) for this exact purpose.
  • All of our engineered Compressed Air Product Kits include a Filter Separator, like this one, for point-of-use removal of solid debris & moisture.

    Air Quality: Dirty air isn’t good for anything.  It’ll clog (and eventually foul) the inner workings of pneumatic valves, motors, and cylinders.  It’s particularly detrimental to the operation of engineered compressed air products…it can obstruct the flow of Air Knives & Air Nozzles, hamper the cooling capacity of Vortex Tubes & Spot Cooling Products, and limit the vacuum (& vacuum flow) capacity of Vacuum Generators, Line Vacs, and Air Amplifiers.

Everyone here at EXAIR Corporation wants you to get the most out of your compressed air use.  If you’d like to find out more, give me a call.

Russ Bowman
Application Engineer
EXAIR Corporation
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When to use Compressed Air Receiver Tanks (and More)

I was recently working with a process Engineer at a food packaging plant on installing a Super Air Knife to blow excess water off a food product. This product was moving single file on a conveyor belt with about 6 feet between each product. The belt was moving pretty slow so we wanted to turn the air knife on only when the product was in front of the knife, which saves compressed air and energy. To do this we used the ELECTRONIC FLOW CONTROL (EFC). If the knife ran the entire time it would be wasting any air blowing during one of the 6′ long gaps. This would also put an unnecessary strain on their already taxed compressed air system. The EFC let him only supply air to the Knife when it saw a product on the belt. To read more about the EFC click here!

efcapp
EXAIR Electronic Flow Control

This application worked perfectly, but they had one other issue. Throughout the day it seemed as if they were losing compressed air pressure at the knife. What they found was during peak compressed air usage in the plant the compressor couldn’t keep up with the demand. Fear not, the Super Air Knife was only running for 7 seconds and was off for 20 seconds. This was a perfect application for EXAIR’s Receiver Tank.

Receiver Tanks are great for applications that require an intermittent demand for a volume of compressed air. This can cause fluctuations in pressure and volume throughout the compressed air system with some points being “starved” for compressed air. EXAIR’s Model 9500-60 60 Gallon Receiver Tank can be installed near the point of high demand so there is an additional supply of compressed air available for a short duration. The time between the high volume demand occurrences should be long enough so the compressor has enough time to replenish the receiver tank.

Receiver Tank
Receiver Tank

If you have a process that is intermittent, and the times for and between blow-off, drying, or cooling allows, a Receiver Tank can be used to allow you to get the most of your available compressed air system. If you need any assistance calculating the need for a receiver, please let us help.

Note – Lee Evans wrote an easy to follow blog that details the principle and calculations of Receiver Tanks, and it is worth your time to read here.

If you would like to talk about any of the EXAIR Intelligent Compressed Air® Products, feel free to contact EXAIR and myself or one of our Application Engineers can help you determine the best solution.

Jordan Shouse
Application Engineer
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Business Benefits Of Compressed Air Efficiency

The primary business benefits of an efficient air compressor system are reduced operational costs, reduced maintenance and increased up-time.  With that being said, is your compressed air system costing you more than you think it should?  Are you having failures, pressure drops, inadequate volume and/or pressure?  You might think from these issues that your system has seen better days and is ready to be replaced.  However, it is possible that your existing tried and true compressor system has more life left in it than you think and with a few simple steps you could have it performing like a champ again!

It is estimated that typically plants can waste up to 30 percent of their generated compressed air and that cost is substantial.  Considering the average cost to generate compressed air is .25 cents per 1000 SCFM, that translates into .075 cents for every .25 cents spent!  Considering that energy costs have doubled in the last five years, it couldn’t be more timely to make your air compressor system more efficient.

So just where is all this waste occurring?  The largest source of compressed air energy waste is from unused or leaked compressed air and that is followed by line pressure drops, over pressurization and inadequate maintenance of the compressor.

So how can you identify this issues in your system?

1). Finding leaks can be accomplished by several methods such as soapy water applied to a suspected joint or connection or the EXAIR Ultrasonic Leak Detector.   It is a high quality instrument that can locate costly leaks in your compressed air system.  When a leak is present and audible tone can be heard in the supplied headphones and the LED display will light.  This testing can be done up to 20′ away so need to get on a ladder!

Leak Detector

2). Pressure drop is caused by is caused by the friction of the compressed air flowing against the inside of the pipe and through valves, tees, elbows and other components that make up a complete compressed air piping system.  If the piping system is to small, the flow (volume) will not be sufficient and the devices will not operate properly.  The volumetric demand would need to be added up to determine if the piping is of sufficient diameter to flow the required volume.  EXAIR’s Digital Flow Meter is an easy way to monitor compressed air consumption and waste.  The digital display shows the exact amount of compressed air being used, making it easy to identify piping that may be undersized.  Installing one on every major leg of your air distribution system to constantly monitor and benchmark compressed air usage is a fast and efficient way to see what your volume through that distribution leg is.

Flow Meter

3). Over pressurization is also an issue, as the pressure is raised to account for high demand periods, system leaks and pressure drops. Unfortunately operating at higher pressures can require as much as 25 percent more compressor capacity than needed, generating wasted air which is called artificial demand.

You can reduce the leakage rate by running the compressor at lower pressures. If you’re short on air, don’t turn up the pressure. Run your compressor at no higher pressure than what you process requires. To relieve peak demands on your system consider the EXAIR Receiver Tank.  It store’s compressed air during low usage times and releases it when the demand is increased without working your air compressor system harder.

receiver_tank

4). Finally, a preventative maintenance (PM) program will need to be implemented to keep the air compressor system running properly.  Two items that are often neglected are the drive belts and filters.  Loose belts can reduce compressor efficiency and dirty filters allow dirt to get through the system and cause pressure drops.  EXAIR has replacement elements for our line of filter separators to keep you air clean and line pressure down.

By increasing your awareness of the health of your air compressor system and implementing a PM program you can significantly reduce your costs from wasted energy and avoid costly down time from an out of service air compressor.

If you would like to discuss improving your compressed air efficiency or any of EXAIR’s engineered solutions, I would enjoy hearing from you…give me a call.

Steve Harrison
Application Engineer
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Receiver Tank Calculations

Receiver Tank

My colleague, Lee Evans, wrote a blog about calculating the size of receiver tanks within a compressor air system.  (You can read it here: Receiver Tank Principle and Calculations).  But, what if you want to use them in remote areas or in emergency cases?  During these situations, the air compressor is not putting any additional compressed air into the tank.  But, we still have potential energy stored inside the tanks similar to a capacitor that has stored voltage in an electrical system.  In this blog, I will show how you can calculate the size of receiver tanks for applications that are remote or for emergency systems.

From Lee Evans’ blog, Equation 1 can be adjusted to remove the input capacity from an air compressor.  This value is Cap below.  During air compressor shutdowns or after being filled and removed, this value becomes zero.

Receiver tank capacity formula (Equation 1)

V = T * (C – Cap) * (Pa) / (P1-P2)

V – Volume of receiver tank (cubic feet)

T – Time interval (minutes)

C – Air requirement of demand (cubic feet per minute)

Cap – Compressor capacity (cubic feet per minute)

Pa – Absolute atmospheric pressure (PSIA)

P1 – Tank pressure (PSIG)

P2 = minimum tank pressure (PSIG)

 

Making Cap = 0, the new equation for this type of receiver tank now becomes Equation 2.

Receiver tank capacity formula (Equation 2)

V = T * C * (Pa) / (P1-P2)

With Equation 2, we can calculate the required volume of a receiver tank after it has been pre-charged.  For example, EXAIR created a special Air Amplifier to remove toxic fumes from an oven.  The Air Amplifier was positioned in the exhaust stack and would only operate during power failures.  In this situation, product was being baked in an oven.  The material had toxic chemicals that had to cross-link to harden.  If the power would go out, then the product in the oven would be discarded, but the toxic fumes had to be removed.  What also doesn’t work during power outages is the air compressor.  So, they needed to have a receiver tank with enough volume to store compressed air.  From the volume of the oven, we calculated that they need the special Air Amplifier to operate for 6 minutes.  The compressed air system was operating at 110 PSIG, and the Air Amplifier required an average air flow of 10 cubic feet per minute from the range of 110 PSIG to 0 PSIG.  We are able to calculate the required receiver volume to ensure that the toxic fumes are evacuated from the oven in Equation 2.

Receiver tank capacity formula (Equation 2)

V = T * C * Pa / (P1 – P2)

V = 6 minutes * 10 cubic feet per minute * 14.7 PSIA / (110 PSIG – 0 PSIG)

V = 8 cubic feet.

Receiver tanks are more commonly sized in gallons.  In converting 8 cubic feet to gallons, we get a 60-Gallon Receiver Tank.  EXAIR recommended the model 9500-60 to be used near the oven to operate the special Air Amplifier during power outage.

Another way to look at Equation 2 is to create a timing equation.  If the volume of the tank is known, we can calculate how long a system will last.  In this example for scuba diving, we can use this information to configure the amount of time that a tank will last.  The diver has a 0.39 cubic feet tank at a pressure of 3,000 PSIG.  I will use a standard Surface Consumption Rate, SCR, at 0.8 cubic feet per minute.  If we stop the test when the tank reaches a pressure of 1,000 PSIG, we can calculate the time by using Equation 3.

Receiver tank timing formula (Equation 3):

T = V * (P1 – P2) / (C * Pa)

T – Time interval (minutes)

V – Volume of receiver tank (cubic feet)

C – Air demand (cubic feet per minute)

Pa – Absolute atmospheric pressure (PSIA)

P1 – Initial tank pressure (PSIG)

P2 – Ending tank pressure (PSIG)

By placing the values in the Equation 3, we can calculate the time to go from 3,000 PSIG to 1,000 PSIG by breathing normal at the surface.

T = 0.39 cubic feet * (3,000 PSIG – 1,000 PSIG) / (0.8 cubic feet per minute * 14.7 PSIA)

T = 66 minutes.

What happens if the diver goes into deeper water?  The atmospheric pressure, Pa, changes.  If the diver goes to 100 feet below the surface, this is roughly 3 atmospheres or (3 * 14.7) = 44.1 PSIA.  If we use the same conditions above except at 100 feet below, the time will change by a third, or in looking at Equation 3:

T = 0.39 cubic feet * (3,000 PSIG – 1,000 PSIG) / (0.8 cubic feet per minute * 44.1 PSIA)

T = 22 minutes. 

If you have any questions about using a receiver tank in your application, you can contact an EXAIR Application Engineer.  We will be happy to solve for the proper volume or time needed for your application.

 

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