I’m often asked how we reduce the water and oil that is needed to cool saws and lubricate guides with our saw guide systems, where others can’t. It’s a simple matter of physics.
Saw guides have a pocket in them that’s designed to hold water up against the saw blade to remove heat. Most systems use water, oil and air that is supplied to the guides to do this. Water is 800 times denser than air and will remove heat more efficiently than air, therefore if you fill the entire pocket with water, it will have the ability to remove more heat, with less water.
Traditional systems have always injected air. One time, when I asked a gathering of engineers why this was done, they all gave me a different answer and started arguing amongst themselves. This proved to me that they didn’t know why, and it was a case of, “we’ve always done it that way.”
Injecting air into the lines was always thought to create turbulence so that the water and oil would mix. This can cause difficulties as the water and air “fight” each other because they are injected at basically the same pressure (one tries to overpower the other.) There is more to it than just removing the air; you have to make some other simple and inexpensive changes to the layout, but the results are positive.
Some of the ripple effects seen in today’s mills go well beyond just the immediate savings in the operational costs of the water and oil. Continuous Dry Kilns are becoming the norm because of their ability to run more cost effectively over traditional heat cycle kilns; they produce better results with the pre-heat dry and conditioning stages and utilize green sawdust as fuel. In order to use this green sawdust as fuel however, the moisture content has to be no higher than 53%. Reducing the water sent to the saws will help lower the overall moisture content of the fuel.
In colder climates, all that water freezes in conveyors and in the bins. Every gallon of water you can remove from the sawdust is 10 pounds (4.5359 Kilograms) less weight in the bins! Preventing it from ending up there in the first place is sometimes difficult to do, without causing burnt saws and guides.
In order to achieve the results needed, there will need to be some controls and components put in place to provide multiple oil volumes to maintain a constant water to oil ratio over the range of water volumes. You can also incorporate electric flow meters, and HMI’s to utilize those signals and display all the flow rates in real time. Real time feed back is what allows you to make very small, exact adjustments to get the system to that sweet spot.
Author: Dean Maier
Industrial Autolube International
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