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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Compressed Air Can Be Costly – EXAIR Can Help You Save It

Growing up across the street from an old fashioned service station does have its perks.   This was one of the old 76  gas stations that still had a garage where a mechanic would fix your car, as well as you could get gas if you needed to.   They even had the rubber hose that would ring a bell when you drive over it.  One of the other things this station had was a compressed air hose that ran to the outside of the building and offered free compressed air to any passer by so they could fill up their tires as needed.   Normally it just had a very simple tire chuck on the end that would connect to the Schrader valve on your car tire.  This station is still there, they no longer sell gas, and they have also removed the bell ringing air hose that runs outside.  If you need a tire filled now, you have to either catch them during normal business hours or move on to the next gas station and hope they have some form of compressed air available.

The full service gas stations for the most part have been replaced by gas stations with convenience stores attached.   They carry more junk food than they do products for your car and they have no need to own or operate an air compressor.   Their customers still have that need though so there are now small stand alone compressed air stations.   These range from small shoebox sized units that you pay a few quarters for, up to the unit I noticed today while filling up my car.

Standalone air compressed for tire inflation.
Standalone air compressed for tire inflation.

This unit takes credit cards, regulates the compressed air to the user selected pressure, and all you have to do is hook it to your cars valve stem.  This is far from free, and the reason is, compressed air is a costly utility.  If you don’t believe us when we repeatedly talk about how much money you can save on compressed air by installing our engineered compressed air nozzles, Super Air Amplifiers or Super Air Knives (among others), then accept a challenge from me.  Contact an EXAIR Application Engineer to discuss any point of use compressed air applications that you have in your facility.   While you are waiting to get the in stock, shipped same day, Intelligent Compressed Air Products® received, monitor your compressed air use and the energy use on your compressor.  Install the EXAIR products once you receive them and continue to monitor your air and energy consumption.   If you don’t see a decrease within these two areas, call me and return the items.   We honor a 30 day guarantee on stock products just so you can make sure you are saving air, and getting the best performance out of your compressed air system.

Brian Farno
BrianFarno@EXAIR.com
@EXAIR_BF