## Air Knife Shim Adjustment can be Key to Successful Applications

On January 2, 1960 Little Anthony & The Imperials appeared on The Dick Clark Saturday Night Beech-Nut Show to sing Shimmy Shimmy Ko Ko Bop. While I wasn’t around at that time, I have heard the song quite a few times and get it stuck in my head more than I have heard it. What does that song and EXAIR have to do with each other? Well, we shimmy shimmy Super Air Knives to dramatically increase or decrease their flow and force.

The stock shim that is assembled in every Super Air Knife is a .002″ (0.05mm) thick. This sets a continuous opening the full length of the knife that drives the performance of the knife. The shim sets the gap height between the cap and the body of the Super Air Knife. If we evaluate a 24″ Super Air Knife with the stock shim installed we could calculate the airflow opening of the knife as the surface area of a rectangle.  To obtain the surface area we take the length of the air knife times the thickness of the shim.  See the example below.

As you can see with the stock .002″ thick shim installed we are actually operating at a surface area opening of 0.048 square inches.  If we were to install the .004″ thick shim into the knife then we would double the height which in turn doubles the surface area, shown below.

This doubling effect will increase the force out of the Super Air Knife when applications require more power.  Thinning out the shim will have the exact opposite effect, if the shim thickness is reduced to .001″ thick then the air consumption and force will be reduced.

Changing the shims out of the Super Air Knives is a fairly simple task as shown in the video below.  Installing a different thickness of shim is a coarse adjustment to the volumetric flow needed for your application.  Then a pressure regulator can be used to fine tune the needed force and flow for the ideal setting to meet your needs, and operate at maximum efficiency for the application.

If you would like to discuss this further or even see what kind of custom thicknesses we can offer on the shims to truly make a tailor fit Super Air Knife for your application, please contact us.

Brian Farno
Application Engineer
BrianFarno@EXAIR.com
@EXAIR_BF

Little Anthony & The Imperials “Shimmy Shimmy Ko Ko Bop” – [Merlin] XelonEntertainment, WMG (on behalf of Turntable Recordings LTD); ARESA, LatinAutor, União Brasileira de Compositores, Spirit Music Publishing, UNIAO BRASILEIRA DE EDITORAS DE MUSICA – UBEM, Abramus Digital, BMI – Broadcast Music Inc., and 4 Music Rights Societies – https://www.youtube.com/watch?v=5mLjZRAXRRA