EXAIR Super Air Knives Provide more Benefit than Blower Air Knives for Green Bean Processing

A customer who was experiencing some issues with a blow off process in their facility contacted EXAIR for a solution. This customer performs post-harvest processing operations on green beans and other vegetables after they’ve been picked. They were having a problem being able to remove excess moisture after the beans had been washed in cold water and keep additional moisture from forming once packaged. The process involved green beans exiting a wash cycle and moving along a belt conveyor. From there, they are dried by a series of blower style air knives. Shortly after being blown off, the beans are weighed and bagged. Once bagged, it was determined that there was too much moisture inside the package and they could not be shipped.

One common issue with blower style knives, and the fundamental issue in this application, is that the air is heated as it moves through the blower. Depending on the type of blower, outlet air temperatures in excess of 180°F are normal. The effect, in this case, was similar to a convection oven where hot air is circulated over the food to cook it. While the beans were not exposed for a long enough time to actually cook, the high temperature air exiting the blower was enough to raise the temperature of the beans. This caused additional moisture to come out from inside the beans after they were bagged and sealed. This is a condition that the customer wanted to avoid because it would lead to the beans drying out and losing their freshness which is a quality issue for the customer.

A second problem was the turbulent airflow from the blower knives causing the beans to be blown all around on the conveyor. The customer effectively had no control over how forcefully the airflow from the blower powered air knives impacted his product. They were either full-on or full-off. This resulted in less than desirable results from a dryness perspective and also caused damage to the product from the high impact disturbance of the blower air knives.

After talking it over with the customer and learning the specifics of the application, we determined that EXAIR’s Super Air Knife Kit Model 110212SS is able to address both of these issues. The airflow would be at ambient temperature, keeping the product at a desired colder temperature. The blowing force could be precisely adjusted with a pressure regulator so as not to cause damage to the product and provide a laminar airflow to strip the water from the product.

EXAIR’s Super Air Knives are available in 303 or 316 grade Stainless Steel to meet the more stringent requirements of many food grade applications. They also operate at a far lower sound level than blower powered air knives, are more compact for easier mounting, and do not involve the purchase of a blower package and associated ducting.

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Model 11006SS Stainless Steel Super Air Knife

Our Application Engineers can work closely with you to resolve any issues you may be having, even if compressed air isn’t currently a part of the process. If your process involves washing, drying, conveying, or packaging food or other products and you can relate to any of the issues above, please keep EXAIR Corporation in mind as a viable solutions provider. Contact an Application Engineer today and we’ll do our best to help you solve your application problems.

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

Bottling Line Can Run Efficiently by Taking a Few Simple Steps

I recently visited a local customer who bottles a liquid drink.  They do two different sizes, single serve and gallon bottles.  The main issues they were having is the gallon bottles were not dry enough after they come out of a cooling / rinse tunnel.  They currently had three different blow off devices in place outside of this cooling tunnel.  The cooling tunnel had hundreds of spray nozzles to both rinse and cool the gallons of liquid.

On the exit of the tunnel there was a blower driven air knife that was being powered by a high maintenance motor that was also sucking in non filtered air to blow the moisture off thee gallon jugs.  The blower was not producing high velocity air and the knife position could not be adjusted for maximum effectiveness due to the hard piping from the blower.

The bottles come out of the blower and go from a 60″ wide conveyor to a 24″ wide conveyor in about five feet of travel. The bottles are then funneled down even further into a single file line and then sped up and sent through two 90 degree bends to try and knock any residual water off them before going into the casing machine.

There were no other blow offs on the gallon line because they were concerned with their compressed air use.  The other two blow offs they had in place were on the single serve bottling line. On that line there were two points that had six separate clusters of a metal flat nozzle that was approximately 1″ wide and were all pointed at a different point of the cap to try and eliminate some moisture that would get trapped under the lip.

The single serve bottles would come out spaced approximately six inches apart but the nozzles were blowing continuously.  This was a very large waste of compressed air.  They could have very easily installed an EXAIR EFC on these supply lines to cut their usage by more than 50% of their current demand.   They then went past an open pipe blow off to help dry the final labeling point.   This was also on continuously which was another opportunity for air savings.

I recommended installing two Electronic Flow Control (EFC) units and replacing their existing nozzles and open pipe with the EXAIR model 1126 1″ Flat Super Air Nozzle outfitted with swivels to allow them to be positioned properly to reach under the bottle cap. Proper positioning, in many cases, increases the effectiveness of the nozzles and can get the job done with fewer nozzles installed. In this application I am confident we can get that bottle cap area blown off with only 2 nozzles.

By eliminating excessive nozzles and cycling compressed air on and off only as needed, the customer saves compressed air. I estimated it was enough compressed air to install a 24″ Deluxe Super Air Knife Kit to blow down on top of the gallon containers, which is the primary reason they asked me to visit in the first place. This will not only give them the 24″ Super Air Knife, but it will also include the crucial EFC and a filter separator to clean the compressed air and a pressure regulator to adjust the pressure down to the minimum necessary for success. All of these factors contribute to optimizing compressed air and using it effectively within anyone’s plant:

  • Eliminate open pipes and ineffective blow offs
  • Turn off compressed air whenever possible
  • Keep it clean to reduce wear and maintenance
  • Adjust the pressure to a minimum level for success

This is just one location in the entire facility where implementing the Electronic Flow Control and EXAIR engineered nozzles will help the customer to optimize their compressed air use.

If you would like to learn more or have questions on any of the EXAIR products mentioned in this blog, feel free to contact us.

Brian Farno
Application Engineer
BrianFarno@EXAIR.com
@EXAIR_BF