Digital Flow Meters Prevent Rework by Measuring Air Flow to a Paint Gun

EXAIR Digital Flowmeter

EXAIR Digital Flow Meters are used to measure compressed air use throughout a facility, and they can also provide preventive measurements for critical processes.

A customer of ours had a paint booth that was used to touch-up large metal panels.  Inside that paint booth, they had two, High Volume Low Pressure (HVLP) paint spray guns.  These paint guns work well as they limit the air pressure to the air cap to reduce overspray and bounce back.  With the lower air pressure, the paint can have a tendency to dry and block a portion of the nozzle.  This can affect the atomization and the lay down of the paint.  To overcome this, operators have a tendency to increase the air pressure which can create other issues in spraying, as well as using excessive paint.  They decided to install some compressed air flow meters in their compressed air lines to monitor their paint system, and with the idea to prevent quality of spray problems before they occur.  They contacted EXAIR to get a better understanding on what we can offer.

In discussing their system, I learned they had an enclosed semi-downdraft spray booth.  They had two runs of ½” NPT Schedule 40 compressed air lines that came from the mainline above.  Both compressed air lines were positioned outside the booth in the left and right back corner.  (Each HVLP spray gun had its own compressed air supply).  The compressed air pipes ran down along the wall with standoffs in the back area.  From there, it elbowed into a filtration system then into the spray booth.  The customer mentioned that he did not have much room between the wall and the spray booth.  The booth had windows located in the door about 20 feet away.  As for their HVLP spray guns, they were set up to operate at 15 SCFM and 30 PSIG.  Depending on how often the spray guns were used during the operation, the paint had a tendency to dry and start to cause blockage.  Before the operator knew it, the paint gun started to become inconsistent, causing blemishes.  They would then have to rework the panel which was costly, affecting profitability.

The EXAIR Digital Flowmeters are designed to measure flow continuously and accurately.  You do not need to weld, cut, or disassemble pipe lines to install.  With a drill guide, the Digital Flowmeter can be easily mounted onto the pipe.  They did not need to unscrew filters, piping, etc. to install these in the back corners of the spray booth.  They just had to drill two small holes, insert the two probes into the holes, and tighten the clamp.  I recommended the model 9090 1/2″ Digital Flow meter.  It has a flow range from 0 to 90 SCFM which was perfect to monitor the HVLP spray guns.  The Digital Flowmeter measures flow by comparative analysis with thermal dispersion; so, the accuracy is very high and recalibration is not required.

Summing Remote Display

Since the Digital Flowmeter was located in the back corner, we needed to get a display over to the viewing window for the operators.  As an option, EXAIR offers a Summing Remote Display, model 9150.  This display has large LED numbers that can remotely displaying the flow from the Digital Flowmeter up to 50 feet away.  They installed the Summing Remote Display and mounted it outside the viewing windows of the spray booth.  The operator could now monitor the flow of the compressed air in real time with just a glance.  Now, when they were spraying paint, they could tell when the flow was starting to decrease.  They could stop and make the necessary changes to the nozzles, reducing the need to rework product.

Being able to measure the unknowns in your compressed air system as a prevention tool, it becomes much easier to evaluate, correct, and discover issues that may occur before they get out of hand.   The EXAIR Digital Flowmeters can give you the real-time flow measurements of your compressed air system to help identify problems.

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

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