Remember the old days of carburetors? Did you ever get the notion to start making small adjustments to see if you could make it run better? Lube systems are the same way and if set-up correctly, they can save all kinds of money, downtime, grief and machines. But get that one guy who wants to start tweaking to “make it run better” and things start running off the rails.
It doesn’t matter if it’s a simple chain lubrication system, a complete canter line or a sawguide system, the basics are the same; a small amount often is the best. A lot of the sawguide systems we run across have been set up to dump a bunch of oil into the system, shut off and then wait a set time to do it again. In the worst case scenario, where a lot of is oil being dispensed, only a small amount of it can really do anything and the rest is just flushed through the system. Then, it has to run without oil for a while until the system does it again.
There is a simple fix, but in most cases we’ve been involved with they don’t want to spend the money to fix it.
What is this process costing you? Plenty!
When you look at what they have been using as a pump, in most cases it is an air operated pump, which provides 60 times more oil than what the system needs at any given time. That’s why they turn it off and on trying to save some of the oil.
Put a flow control in the main supply line and turn down the flow rate to a point where the volume being dispensed is providing a constant volume required over time. This maintains an even oil film on all the parts providing a much better lubrication scenario than the Flood/Starve operation it’s set-up as.
Essentially, the volume you want to apply should be set up like a dripping hot water tap. A drip every few seconds doesn’t seem like much, but over the course of a month, it adds up to a hot water tank. You’re still paying to heat that water so why not use it wisely. In any application you’ll have to do some math and figure out where you want to go.
There are calculations out there that can help you figure out the volume that specific component will require. It’s generally over a week or an hour, depending on the application and conditions.
Just for example, if a chain needs three gallons a week, what kind of performance do you get by dumping a jug on it every weekend? It’s generally gone in the first shift and then its running dry and wearing after that.
The Calculation:
- 3 gallons is 693 cubic inches (231 cubic inches per gallon).
- If the mill is running 2 shifts, that is 80 hrs.
- Setting the system up to dispense 3 gallons over 80 hours is then a case of simple math. It works out to 8.66 cubic inches per hour.
- A drop of oil is roughly 0.003 cubic inches
- 8.66 cubic inches is roughly 2,887 drops, and
- Spread out over an hour is one drop every 1.25 seconds.
If you drop the oil onto a felt running on the chain, every rotation picks up more oil, rather than potentially just dropping though the chain. At the end of the week, there is still oil on the chain, its seen very little wear and will last you a much longer time. This little tweak is very easily done, doesn’t cost a lot and in most cases can be on existing system run by your PLC.
Let me go back to that sawguide system now. The one that was set up by the manufacturer and controlled by the PLC. The system turned on the main oil valve every minute for 55 pulses from the divider valve fitted with a prox switch. Those 55 pulses happened within the first 10 seconds and then shut it off then no oil for 50 seconds. The customer couldn’t figure out why they were not getting any life out of the guides, doing two to four saw and guide changes per shift. We installed a flow control and choked it back so it took about 57 seconds to get those 55 pulses. After that small tweak, the guide life improved dramatically to a set a shift and most of the guides were still fine.
If the tweaks are done right, little ones can have not only a big difference, they can be huge.
Author: Dean Maier
Dean has been in the automated lubrication business for 25 years, with 85% of that time spent in forestry applications. We are delighted to have his insight with this latest blog.
Industrial Autolube International Inc.
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