One of the more popular treats for kids and adults are gummies. They can be sweet, sour, and in different shapes and colors. A candy company that makes gummy bears was looking for a better way to spray food-grade oil onto their product. They contacted EXAIR about our Air Atomizing Spray Nozzles.
We discussed their setup and process for making the gummy candies; or in this case gummy bears. The sugary mixture is poured into molds that are coated with corn starch. The corn starch helps to keep the gummy from sticking to the mold. Once hardened, the bears will be released from the molds and travel through a stainless-steel spinning drum. In here, they apply a light food-grade oil onto the bears. This process will hide the starch and give the candy that glazed and colored feature. The drum was near 60” (1.52 meters) long and spun at 19 RPM. The gummy bears would tumble along the length of the drum at a designed production rate of 2000 Kg/hr. (4,400 Lbs./hr.). They used drip tubes along the top to apply the food-grade oil onto the gummy bears. They noticed that the color was not as good and the coverage was spotty. The oil pump was metered in a range of 0.35 – 3 gal/hr. (1.32 – 11.3 l/h). The temperature inside the drum could reach up to 150oF (65oC), and the viscosity of the food-grade oil ranged between 190 – 400 cps. In order to get the best results for quality, they had to reduce their production rates to about 1,700 to 1,800 Kg/hr.
To determine the correct solution, we had to dive a bit more into their application. The details of the EXAIR Atomizing Nozzles are measured with water as the liquid. Since they are using an oil at different temperatures, the specific gravity will change slightly. For their oil, the specific gravity is 0.92 at 20oC and 0.89 at 65oC. We can use Equation 1 to convert the required flow rate from the food-grade oil to water.
Equation 1:
Q1 = Q2 * SQRT (SG2 / SG1)
Q1 – Flow of water (gph)
Q2 – Flow of oil (gph)
SG1 – Specific Gravity of water
SG2 – Specific Gravity of oil
The Specific Gravity of water is 1. With the range of specific gravity for the oil, we can calculate the range that is needed as indicated by water. Then we can make a selection as referenced by our data in the catalog. Since we want to make sure that we can cover the range of the metered oil pump, we will use the maximum flow rate of 3 gph. In adding the values, we get the following:
@20oC Q1 = 3 gph * sqrt(0.92) = 2.88 gph
@65oC Q1 = 3 gph * sqrt(0.89) = 2.83 gph
Since the viscosity ranges above 300 cps., I recommended the External Mix Atomizing Nozzles to be mounted along the length of the rotating drum. The External Mix can handle viscous liquids up to 800 cps. Unlike the drip method, the EXAIR Liquid Atomizing Spray Nozzles use compressed air to shear the oil into small droplets and to disperse the oil in a wide pattern. With the smaller particle size, we can get more coverage area which will allow them to use less food-grade oil. The coverage area on the gummy bears was near 15” (38cm) as they rolled down the drum. I also recommended the No-Drip option to allow for versatility in their process. The No-Drip option for the Atomizing Nozzles is a very nice option which will stop the liquid solution from dripping when not in use. When they needed to apply the oil, they would just turn on the compressed air to the Atomizing Nozzle. It made it very easy to control. This was important to reduce excess usage and non-conforming parts. It also keeps the inside of the drum oil free during cleaning cycles.
From the data above, I recommended three pieces of the model EB2010SS, No Drip External Mix Wide Angle Flat Fan Pattern. The spray pattern was 14” (35.6cm) wide to cover part of the 60” (1.52m) length of the drum. With an estimated 1 gph for each nozzle, we would be able to spray the maximum requirement as calculated above (2.88 gph). After installation, they were able to get a consistent deep color of the gummy bear at the maximum production rate of 2,000 Kg/hr. They also noticed that with the fine particle spray, they were able to use less oil. With the three pieces of the model EB2010SS, they were able to reach maximum production rates with less food-grade oil and reduce scrap rates.
If you have a liquid that you would like to spray evenly, efficiently, and effectively; EXAIR Atomizing Nozzles can do that for you. You can contact an Application Engineer for help. For the customer above, they were able to create those gummy treats for kids and adults. Yummy.
John Ball
Application Engineer
Email: johnball@exair.com
Twitter: @EXAIR_jb
Picture: Giant Gummy Bear by Alexas_Fotos. Pixabay licence.