A food manufacturing company was looking for a more efficient way to dry polypropylene trays that were filled with food product. With their current operation, they would send already packed and sealed food trays through a washing system that used sterilized water. The trays would then have to be dried prior to bulk packaging. The operators would place the trays side by side on a 24” wide open-mesh stainless steel metal conveyor with two or three trays at a time (depending on the tray dimensions). They contacted EXAIR because they wanted to replace their “old and inefficient system” with something better.

In my discussions, they gave some additional details of the operation and the problems that they were seeing. The dimensions of the trays ranged from 150 to 200mm long by 100 to 150mm wide by 35 to 50mm in height. They were cleaning at a rate of 30 trays per minute through the washing and drying system. The washer was designed to recycle the water to improve “green” operations. But the trays were carrying much of the water outside the machine. Thus, they would have to stop and refill the wash system with fresh water.

After the washing cycle, the drying section began. It consisted of two parts; a sponge roller and a heated chamber that would blow hot air. First the trays would run under the sponge roller to absorb the water from the top of the trays. A feature that they did not like was the continuous adjustment to the sponge roller for the different tray heights. They had to make sure that they had good contact without stopping the movement.

Also, with bulk of the water being on top of the trays, the sponge surface would get saturated. They would have to stop the process to change with a dry foam pad or replace due to wear. After the sponge roller, it would move into a heated chamber to remove the remaining portion of the water from the trays. They used a 11 KW heating system to blow hot air. This part of their system required a lot of electricity to run. They wondered if EXAIR could help streamline their process and reduce energy costs.

They sent a photo of their system, reference above. As described, the trays were moving intermittently through the wash cycle and then into the drying operation. When gaps are present in a process, the Electronic Flow Control, or EFC, becomes a great product for energy efficiency. It is designed to use a photoelectric sensor to detect a part and initiate a timing sequence. Using a solenoid valve, it will turn on the compressed air only when needed. With the drying operation, I suggested that they could remove the sponge roller and heated chamber, and replace them with two Super Air Knives. In conjunction with the EFC, we can decrease energy usage, reduce downtime, and increase savings. Profit margins can be critical in the food industry, and EXAIR has many ways to help.

To expand a bit more about revitalizing the “old and inefficient system” with EXAIR products, I made some suggestions. I recommended two Stainless Steel Super Air Knife Kits, model 110224SS, to be placed near the end of the conveyor. One Super Air Knife would be positioned above the tray to blow across the top; and one would be positioned below the tray under the mesh conveyor to blow across the bottom.

At a slight blowing angle in a counter-flow direction, the air streams would remove the water from the top and bottom of the tray at the same time. This would create a non-contact “wiping” solution. Now they do not have to worry about parts wearing out due to contact. Another unique feature of the Super Air Knife is the strength of the laminar air stream. It is consistent from 3” (76mm) to 12” (305mm) away from the target. Thus, they can easily set the height of the Super Air Knives to dry all the different trays without adjusting it.

And as an added benefit, the water that was being blown off the trays by the Super Air Knives remained within the washing system. The sterilized water was not being wasted and could be recycled. With the Electronic Flow Control, I recommended the model 9056. It is a user-friendly device with eight different timing sequences. They were able to position the photoelectric sensor near the outlet of the washing system. As soon as the trays were detected, the Super Air Knives would turn on to blow two or three trays at the same time. With the EXAIR products installed, the system went from using 11 KW down to 4 KW, a 63% savings.

EXAIR has helped many customers like this one above. When it comes to energy savings, EXAIR leads the way. With two Super Air Knives and an EFC, we were able to modernized their system; save on water, improve productivity, reduce the overall footprint, and save on their energy usage. If you have a similar application, you can contact an Application Engineer at EXAIR. We will be happy to update your system.

John Ball
Application Engineer
Email: johnball@exair.com
Twitter: @EXAIR_jb