McLanahan Log Washers Still an Industry Staple after More Than a Century
The Log Washer was invented in 1891 by Samuel Calvin McLanahan, the second generation of family ownership of McLanahan Corporation, to remove clay from gravel, various types of ores and crushed stone to improve the quality of the material.
Samuel Calvin’s design featured paddles bolted to squared-off tree logs, which is how the Log Washer got its name. The paddles on the counter rotating log shafts agitated the material to facilitate particle-on-particle scrubbing as well as moved the cleaned material toward the discharge end. Liberated clay was removed with the wash water from near the feed end of the machine.
“It was quite an invention, and we still manufacture it,” said Michael McLanahan, Chairman of McLanahan Corporation’s Board of Directors and Samuel Calvin’s great-grandson.
Improving the design
The Log Washers McLanahan builds today function the same as Samuel Calvin’s original machine, but they look quite different. For one, the shafts are no longer made of tree logs; they have been replaced by an all-steel construction.
The paddles on the shaft have also been updated through the decades, as have the position of the paddles and shafts. These design changes helped improve the wear life of the Log Washer and its components.
Another design update to increase longevity was the change from box and thimble outboard bearings to roller bearings, which are easier to maintain and improve machine operation.
“It is a good design that has evolved through several iterations over the years,” Michael said. “We’ve worked closely with our customers to improve the design based on their experiences operating them in the field.”
Features of McLanahan Log Washers
- Drives – All McLanahan Log Washers employ a V-belt-drive, single-input, dual-output gear reducer, which can be uncoupled from the log shafts and frame for maintenance.
- Log shafts – The McLanahan log shaft design handles large tonnages with less power and less water. Wear collars are utilized at the feed-end flanged connection to protect the connection bolts, bearing and bearing housing from wear.
- Paddles – The paddles are designed to optimize the combination of hardness and ductility to maximize abrasion resistance.
- Spray bars – All McLanahan Log Washers come standard with a center spray bar to provide a final rinse before the material is discharged from the washer box. Wash water from the spray bars carries the dissolved clay or organics to the feed end of the machine, where it is removed with the overflow.
- Submerged bearings – McLanahan submerged rear bearings feature seals that keep water and even the smallest particles from reaching the bearings.
- Optional clean-out doors – McLanahan supplies drop-bottom doors in the bottom of the Log Washer box for easier cleaning during maintenance or seasonal shutdown.
- Slope adjustment – McLanahan offers either mechanical or hydraulic slope adjustment to provide additional washing for removing tougher materials.
Log Washers today
While Samuel Calvin originally invented the Log Washer for iron ore, it was soon applied to other materials, such as gravel, rock and crushed stone. More than a century later, Log Washers are still a staple in both the aggregate and minerals processing industries for removing tough clays and improving final products.
“The Log Washer was not a one-hit wonder — it carried on throughout the years and is still needed. We’re still selling them today to do the same thing, just in a better way — more efficient and lower cost to the operator,” McLanahan said. “It’s a good, sturdy, long-lasting machine that’s a good investment for those companies that need to remove clay and organics from their ores.”