Pressure – The Inner Working of the Basic Pressure Gauge

Everyday here at EXAIR we talk about pressure, specifically compressed air pressure. The other day I was looking up our model 9011, 1/4″ NPT Pressure Gauge , and it got me to wondering just how does this small piece of industrial equipment work. The best way to find out is to tear it apart.

9011_exair

Most mechanical gauges utilize a Bourdon-tube. The Bourdon-tube was invented in 1849 by a French watchmaker, Eugéne Bourdon.  The movable end of the Bourdon-tube is connected via a pivot pin/link to the lever.  The lever is an extension of the sector gear, and movement of the lever results in rotation of the sector gear. The sector gear meshes with a spur gear (not visible) on the indicator needle axle which passes through the gauge face and holds the indicator needle.  Lastly, there is a small hair spring in place to put tension on the gear system to eliminate gear lash and hysteresis.

When the pressure inside the Bourdon-tube increases, the Bourdon-tube will straighten. The amount of straightening that occurs is proportional to the pressure inside the tube. As the tube straightens, the movement engages the link, lever and gear system that results in the indicator needle sweeping across the gauge.

Pressure Gauge Top

The video below shows the application of air pressure to the Bourdon-tube and how it straightens, resulting in movement of the link/lever system, and rotation of the sector gear –  resulting in the needle movement.

If you need a pressure gauge or 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.

Brian Bergmann
Application Engineer

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EXAIR Provides Quick Blowoff Solution for Gauge Manufacturer

I was recently contacted by a manufacturer of custom measurement systems. They were working on a design for a system that could measure (2) different sizes of gears with a high degree of accuracy. A robotic arm would pick up the gear off of a conveyor and deposit it onto a gauge for inspection.

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The two gears being measured

During the initial quoting phase of the project they had been a little misled. They were told that the gears would be completely clean and free of debris before being deposited on the conveyor and picked up for inspection.  It turns out this would not be the case. Chips, oil, or debris remaining on the gear would result in false part rejection. With the required completion date looming, they reached out to EXAIR for some help in implementing a solution to clean the gear before inspection.

While blowing off the oil or chips from the gear was the primary concern, having this debris flying around inside the machine could have been problematic as well. We needed to find a way to contain the chips and remove them. In the process, there was a brief moment that the robot arm held the gauge in place just prior to depositing it onto the gauge. It was there that we identified an opportunity to both clean and remove the chips that were blown off the gear. Using a Model 1105 3/8 NPT Super Air Nozzle and Model 9068 Swivel, they were able to precisely position the blowoff to hit across the bottom of the gear where the chips were located. They then 3D printed a shroud to contain the area where the gauge was held and the blowoff would be performed. They designed the shroud with a 1-1/4” outlet to connect directly to our Model 6082 Line Vac. The intake of the Line Vac was installed right at this point and was set to activate as soon as the air nozzles began their cleaning cycle. The chips were blown off of the gears, contained by the shroud, and taken away to a bin underneath the machine by the Line Vac. The crisis was averted!!

This was the first time they had implemented some type of method to clean the part before measuring. In the past, they had lost potential projects due to the inability for them to provide a clean part for measurement. With this newfound method of part cleaning, they’re now able to be a more complete solutions provider to their customers. They’re able to design the part cleaning feature into the process from the start, rather than retroactively as they had to do here.

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Model 6082 Aluminum Line Vac

At EXAIR, we understand how problems can crop up during design and cause potential delays in the completion of a project. For this reason, we keep all of our catalog products in stock and ship same day with an order placed by 3:00 pm EST. This customer was local and was able to call in with a problem, determine a solution, and come pick up their order the same day. If you are having difficulty cleaning or drying machined parts, give us a call. EXAIR has the solution, in stock, ready to ship to you immediately.

Tyler Daniel
Application Engineer
E-mail: TylerDaniel@exair.com
Twitter: @EXAIR_TD