A few months ago, I took a phone call from a manufacturing engineer who worked at a large candy production facility here in the United States. Extra chocolate was dripping out of the candy molds onto the conveyor belt below. Within a few hours the belt was dirty enough they would have to stop the line and clean the residual chocolate off the belt.
The best solution I found was a 72” 316 Stainless Steel Super Air Knife. It worked great when powered at 60 psig inlet pressure. The laminar flow of the Super Air Knife was perfectly suited for this application. The knife was mounted between the mold and the belt to help solidify and blowoff the excess drips of chocolate. There was one drawback, the Super Air Knife was not needed to blow the belt continuously and the continuous demand was not desirable during peak production.
The simple solution for this was the EXAIRElectronic Flow Control, the EFC minimizes compressed air use by turning off the air when a sensor is triggered. Since there was a 4.5-minute time gap between each mold set this was a great solution. When the photoelectric eye saw a mold, it then told the solenoid valve to open and supply the knife with compressed air for 30 seconds while the mold was open and the excess chocolate would be dripping. See the Savings calculations below;
165.6 SCFM x 60 minutes x $ 0.25 / 1000 SCFM = $ 2.48 per hour
$ 2.48 per hour x 8 hours = $ 19.84 per 8-hour day
$ 19.84 x 5 days = $ 99.20 per work week
$ 99.20 per week x 52 weeks =$5,158.40 per work year without the EFC control
With the EFC installed (turning the compressed air off for 4 minutes 30 seconds with a 30 second on time = 6 minutes/hour compressed air usage)
165.6 SCFM x 6 minute x $ 0.25 / 1000 SCFM = $ 0.25 per hour
$ 0.25 per hour x 8 hours = $ 2.00 per 8-hour day
$ 2.00 x 5 days = $ 10.00 per work week
$ 10.00 per week x 52 weeks = $520.00 per work year with the EFC control
$ 5,158.40 per year (w/o EFC) – $ 520.00 per year (w/ EFC) = $4,638.40 projected savings per year by incorporating the EFC.
This example illustrates, clearly, why choosing the EFC is a good idea. It has the ability to keep compressed air costs to a minimum and saves compressed air for use within other processes around the plant. With this type of compressed air savings, the unit would pay for itself in less than 3 months.
I was recently working with a process Engineer at a food packaging plant on installing a Super Air Knife to blow excess water off a food product. This product was moving single file on a conveyor belt with about 6 feet between each product. The belt was moving pretty slow so we wanted to turn the air knife on only when the product was in front of the knife, which saves compressed air and energy. To do this we used the ELECTRONIC FLOW CONTROL (EFC). If the knife ran the entire time it would be wasting any air blowing during one of the 6′ long gaps. This would also put an unnecessary strain on their already taxed compressed air system. The EFC let him only supply air to the Knife when it saw a product on the belt. To read more about the EFC click here!
This application worked perfectly, but they had one other issue. Throughout the day it seemed as if they were losing compressed air pressure at the knife. What they found was during peak compressed air usage in the plant the compressor couldn’t keep up with the demand. Fear not, the Super Air Knife was only running for 7 seconds and was off for 20 seconds. This was a perfect application for EXAIR’sReceiver Tank.
Receiver Tanks are great for applications that require an intermittent demand for a volume of compressed air. This can cause fluctuations in pressure and volume throughout the compressed air system with some points being “starved” for compressed air. EXAIR’s Model 9500-60 60 Gallon Receiver Tank can be installed near the point of high demand so there is an additional supply of compressed air available for a short duration. The time between the high volume demand occurrences should be long enough so the compressor has enough time to replenish the receiver tank.
If you have a process that is intermittent, and the times for and between blow-off, drying, or cooling allows, a Receiver Tank can be used to allow you to get the most of your available compressed air system. If you need any assistance calculating the need for a receiver, please let us help.
Note – Lee Evans wrote an easy to follow blog that details the principle and calculations of Receiver Tanks, and it is worth your time to read here.
If you would like to talk about 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.