Don’t Fall Victim To Undersized Piping

Pressure drops, incorrect plumbing, undersized piping, insufficient flow; if you hear these terms from tech support of your point of use compressed air products or from your maintenance staff when explaining why a process isn’t working then you may be a victim of improper compressed air piping selection.
Often time this is due to a continued expansion of an existing system that was designed around a decade old plan. It could also come from a simple misunderstanding of what size of piping is needed and so to save some costs, smaller was used. Nonetheless, if you can understand a small number of variables and what your system is going to be used for, you can ensure the correct piping is used. The variables that you will want to consider when selecting a piping size that will suit your need and give the ability to expand if needed are shown below.

  • Minimum Operating Pressure Allowed (psig) – Lowest pressure permitted by any demand side point of use product.
  • System Pressure (psig) – Safe operating pressure that will account for pressure drops.
  • Flow Rate (SCFM) of demand side (products needing the supplied compressed air)
  • Total Length of Piping System (feet)
  • Piping Cost ($)
  • Installation Cost ($)
  • Operational Hours ( hr.)
  • Electical Costs ($/kwh)
  • Project Life (years) – Is there a planned expansion?

An equation can be used to calculate the diameter of pipe required for a known flow rate and allowable pressure drop. The equation is shown below.

A = (144 x Q x Pa) / (V x 60 x (Pd + Pa)
Where:
A = Cross-Sectional are of the pipe bore. (sq. in.).
Q = Flow rate (cubic ft. / min of free air)
Pa = Prevailing atmospheric absolute pressure (psia)
Pd  = Compressor discharge gauge pressure (psig)
V = Design pipe velocity ( ft/sec)

If all of these variables are not known, there are also reference charts which will eliminate the variables needed to total flow rate required for the system, as well as the total length of the piping. The chart shown below was taken from EXAIR’s Knowledge Base.

Once the piping size is selected to meet the needs of the system the future potential of expansion should be taken into account and anticipated for. If no expansion is planned, simply take your length of pipe and start looking at your cost per foot and installation costs. If expansions are planned and known, consider supplying the equipment now and accounting for it if the additional capital expenditure is acceptable at this point.

The benefits to having properly sized compressed air lines for the entire facility and for the long-term expansion goals makes life easier. When production is increased, or when new machinery is added there is not a need to re-engineer the entire system in order to get enough capacity to that last machine. If the main compressed air system is undersized then optimal performance for the facility will never be achieved. By not taking the above variables into consideration or just using what is cheapest is simply setting the system up for failure and inefficiencies. All of these considerations lead to an optimized compressed air system which leads to a sustainable utility.

Brian Farno
Application Engineer
BrianFarno@EXAIR.com
@EXAIR_BF

Intermediate Storage Tanks & How To Size Them

When evaluating processes that utilize compressed air and adhering to the Six Steps to Compressed Air Optimization, intermediate storage proves to be a critical role coming in at step number five. Intermediate storage tanks may already be in place within your facility and often times can be implemented as modifications to aid existing lines that are struggling to maintain proper availability of compressed air to keep the line at peak performance.

EXAIR Receiver Tank in 60 Gallon Capacity

When determining whether or not a production line or point of use compressed air operation would benefit from a receiver tank/intermediate storage we would want to evaluate whether the demand for compressed air is intermittent.  Think of a receiver tank as a capacitor in an electrical circuit or a surge tank in a water piping system.  These both store up energy or water respectively to deliver to during a short high demand period then slowly charge back up from the main system and prepare for the next high demand.   If you look from the supply point it will see a very flattened demand curve, if you look from the application side it still shows a wave of peak use to no use.

Intermittent Applications are prime for rapid on/off of compressed air.

One of the key factors in intermediate storage of compressed air is to appropriately size the tank for the supply side of the system as well as the demand of the application.  The good news is there are equations for this.  To determine the capacity, use the equation shown below which is slightly different from sizing your main compressed air storage tank.  The formulate shown below is an example.

Where:

V – Volume of receiver tank (ft3 / 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)

One of the main factors when sizing point of use intermediate storage is, they are being supplied air by smaller branch lines which cannot carry large capacities of air.  That limits your Cap value. The only way to decrease the V solution is to increase your Cap. The other key point is to ensure that all restrictions feeding into the tank and from the tank to your point of use are minimized in order to maintain peak performance.

If there are intermittent applications that are struggling to keep up with the production demands within your system, please reach out and speak with an Application Engineer.  We are always here to help and we may even be able to help you lower the demand needed by utilizing an engineered point of use compressed air solution.

Brian Farno
Application Engineer
BrianFarno@EXAIR.com
@EXAIR_BF

Need More Capacity? Start By Finding it in House or Renting

I field a decent number of calls from companies that are trying to expand to new lines or venture into an area of production that they have not crossed into before.  Maybe it is bringing a process in-house that they traditionally outsourced, or altering a process that now requires a large scale blow off operation. In many cases, as these companies grow and succeed, their compressed air systems grow with them. Some of them need to find out find out how much air they will need if when they make decisions to bring processes in house or expand a current process.

One of the first options when needing more capacity from your current compressed air system is to take a look at the existing demand side and determine if we can free up enough supply to meet the requirements of this new option.   Let’s say for instance a new 60″ Super Air Knife is needed.   To test that unit at 80 psig inlet pressure we would need to free up 174 SCFM of compressed air. In all the years we have been around it is still surprising to consult with customers who are using large numbers of open blow-offs, homemade air knives, coolant hoses and nozzles for compressed air etc. These companies can find that extra capacity in their current systems by retrofitting engineered solutions on to the aforementioned poor solutions for keeping compressed air efficient. IF you are using some of those solutions, call EXAIR today to find out how much air our products may save you.

In the event that is not possible to find the necessary new volume of compressed air by streamlining your current system, it means looking at adding compressor capacity.  Some companies think they have to go out to buy a new compressor immediately, simply to test this new process.   That is more often than not, false.   The best recommendation I have is to look into renting a compressor, much like the one shown below.

A Rental Tow Behind Air Compressor
A Rental Tow Behind Air Compressor

The compressor distribution piping.
The compressor distribution piping.

I saw this unit while I was jogging, well attempting to jog, on my lunch break.  This was outside a local company that apparently, going through a very similar scenario like I mentioned above.  When I looked a little closer, I noticed the unit included around a 75-100′ of hose that did not use the dreaded quick disconnect fittings everyone sees.  Instead it utilized what I know as a Chicago style air fitting which does not restrict the air flow nearly as much as a quick disconnect and permits you to utilize the largest volume of compressed air from the compressor – remember folks: properly sized compressed air lines and fittings are extremely important when needing to keep volume and pressure of compressed air at high levels.

A Chicago Style Air Fitting
A Chicago Style Air Fitting

 

Once I looked up the statistics on the compressor I found that it will generate up to 375 CFM at 150 psig.  This is more than enough to test or run a 60″ Super Air Knife and validate whether additional compressors are needed, as well as if the Super Air Knife will perform to meet your needs.   Then, when you are done with the test, you can simply return the air compressor. Based on the results of this test, this could be another point to decide if you could save the needed air from your current system or if you would require a new compressor.

The EXAIR Guarantee
The EXAIR Guarantee

The moral that I am trying to instill in this blog is simple.  If you have a need for more compressed air to validate a new or improved process, don’t hesitate to think outside of your existing system. Where there is a will and a need, there is a way.  If it doesn’t work, take advantage of our 30 day unconditional trial.

Brian Farno
Application Engineer
BrianFarno@EXAIR.com
@EXAIR_BF

The Value Of Knowing

One of my many favorite shows as a child was the animated series G.I. Joe.  Through the main story line, they tried to teach a life lesson at the end of every episode.   Then the famous saying would come out.   “Knowing is half the battle.”  This has proved to be extremely true and helpful throughout my life and my career.

The biggest lesson that I believe I have learned is that when you don’t know the answer, ask for help.  Knowing the right person to ask is quite often just as good as knowing the information yourself.   This is why the Application Engineering team here at EXAIR is comprised of people from such diverse backgrounds.

If one of us is unfamiliar with your application there is most likely someone nearby who has been exposed to your industry or specific process.  For instance, I have a machine tool background, and you call to discuss discharge of our Reversible Drum Vac versus some other mechanical pump, then I may ask Justin Nicholl or Russ Bowman about the mechanical pump for help with understanding your situation.  This also showcases just how much of a team effort goes into solving problems for our customers.

Fortunately for us, the company also backs us up when we run across an unfamiliar process or problem. EXAIR’s 30 day guarantee allows us to get the product into your hands so you may test it risk free for 30 days. Test it within your facility under your conditions for a real world result. We enjoy learning about new processes and problems, plus we get to add this knowledge to our diverse experience.

Just in case you were wondering what kind of experience we have at our disposal, here is a brief listing of our core knowledge. If we were to include our internships, educations, field experience and people who are still at EXAIR but were once in the Application Engineering department, this list would go on and on:

  • Machine Tool
  • Injection Molding
  • Industrial Pumps
  • Natural Gas Regulators
  • Petroleum Nozzles
  • Compressed Air Hand Tools
  • Industrial Supply
  • Electronic Sensors / Transducers
  • Aerospace
  • Mechanical Power Transmission

So as you can see, if we don’t know about it or haven’t seen something like it,  chances are you have a unique application that we are still going to do our best to help with.

If you have any questions or would like to discuss one of our compressed air applications, feel free to contact us.

Brian Farno
Application Engineer
BrianFarno@EXAIR.com
@EXAIR_BF