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

The Sweet Taste of Floss Part II

Floss Stick

Floss Stick

In The Sweet Taste of Floss Part 1, I explained the benefits of using our Atomizing Nozzles to apply a liquid flavoring onto floss sticks. With that same customer, we had another opportunity to save them on compressed air and on liquid flavoring.

As described in their setup, they had a mini conveyor that would carry a 24” rod that was filled with many floss sticks. This operation was manual.  It would take the operators roughly 45 seconds to load the floss sticks.  The conveyor would move the rod through the spraying compartment in about 15 seconds.  The customer was worried about the continuous spraying and wondered if we could help in this operation.

Electronic Flow Control

Electronic Flow Control

They had a good concern because with a constant spraying, they could have an issue with fogging the work area and wasting the liquid cherry flavoring. My suggestion was to use the EXAIR model 9055 Electronic Flow Control (or EFC).  The EFC is a user-friendly controller that combines a photoelectric sensor with a timer.  It has eight different programmable on/off modes to minimize compressed air usage and in this case, liquid spray.  For this type of operation, the EFC worked great.  They did not need to manually turn on and off the system, or purchase a PLC that would require programming.  The EFC is in a compact package that is easy to mount and setup.

In evaluating their application, the Signal “OFF” Delay would be correct setting to run in this operation. (The EFC comes factory set in this mode).  The sensor will detect the part and open the solenoid immediately.  Once the part clears the sensor, then it will keep the solenoid open for the set amount of time.  For this project, they set the timer for 15 seconds.  They mounted the photoelectric sensor at the beginning of the entrance to the spraying compartment.  Once the sensor detected the rod that was filled with floss sticks, it would turn on the compressed air to the Atomizing Nozzles.  After the timing sequence hits 15 seconds, the EFC would turn off the solenoid which would stop the spraying.  It would rerun this sequence every time a rod would pass by the sensor.  This optimized their operation; especially when they had any issues with loading the rod with floss sticks.  It reduced their liquid and compressed air usage by 75%, and it kept the work area free of fog.

If you need an easy way to save on compressed air usage or in this case fluid, the EFC could be the device for you. It can save you much money in your operational costs, and during these economic times, we know that every bit counts.  If you are still a little “foggy” on the EFC, you can contact an Application Engineer at EXAIR for help.

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

 

Photo by homejobsbymom with Creative Commons license.

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