At EXAIR we have two departments, one that takes care of domestic customers and another that takes care of our overseas customers. I work in our international department and occasionally get to go on trips around the world to meet with distributors and end customers to discuss applications and educate customers about EXAIR product.
On my most recent trip to Santiago, Chile, I was fortunate to take a tour through a tire manufacturing facility. The application we were there to see was for cooling. The customer had made efforts to improve their approach but it was not having a positive effect and they needed some help in determining a better alternative.
In the above photo, you can see two strips of extruded rubber pre-form material. The material in the photo is extruded and cooled in a water bath. The material travels from right to left in this photo. As the material is travelling up and out of the water bath, the customer wants to blow it dry and also continue the cooling process by blowing air onto the material. The problem was that the customer had installed two large blower packages with blower style air knives to drive the water down the incline and off the material. The problem with the blower air knives is that the air they were exhausting was at 80C (176F) which had a heating effect on the rubber, not a cooling one. In this case, the customer had tried to install two 42 inch Super Air Knives in addition to the blower air knives but they were not seeing any positive effect as the air pressure being used at the Super Air Knives was only about 2 BARG (29 PSIG). After inspecting the EXAIR Air Knives, their operating pressure and their position, I was quickly able to form a plan of action that the customer could follow to eliminate the blower air knives, blow the water off the extruded rubber more effectively and cut down on the overall energy use for the whole application.
Notice in the above photo that the water is tracking on the left hand side as the material moves from left to right. All of the air knives are located up to the right out of the frame of the photo. They are blowing counter to the flow of material. Also, notice the set of rollers and weights used to hold the material down as it makes the transition from horizontal to 45 degree angle. A big part of the problem is the relative location of the blowing devices. They are located on one side of the roller and the actual water is on the other. The roller essentially acts as a barrier to the continued airflow down the material and so is not very effective for driving the water off the extrusions. So, the first recommendation was to move the Super Air Knives up-stream to a point just in front of these rollers so the airflow is no longer blocked by the roller. The second recommendation was to cut down from (2) 42″ Super Air Knives that cover the full width of the machine, to (2) 12″ Super Air Knives that covered only the width of the two strips of extruded material. The reduction in air knife length represents a savings of 72% on the compressed air usage which should enable the customer to generate a higher blowing force due to lower air consumption and higher pressure of operation. Since the Super Air Knife installation can be optimized in this way, there is no need for the high heat blower air knife system which was actually putting more heat into the material.
The point of this story is that sometimes you can have the right tool in your possession but you may not be using it to its fullest potential or even in a wrong way that creates more problems. This is why we (EXAIR Application Engineers) are here, to help customers figure out the best implementation of the EXAIR product they are using. We want our customers to be successful, hopefully the first time they install the product. But if not, our eyes and ears are open to observe your process and give you our best advice on how to proceed.
Neal Raker
Application Engineer
nealraker@exair.com