McLanahan Tailors Fine Material Screw Washer for Unique Application

A 20”x25’ McLanahan Fine Material Single Screw Washer is on its way to a unique application in Texas.

The customer will be using the screw washer to separate sand from a slurry of oil well drillings. The sand screw will be installed in a steel container to prevent the drilling fluid that overflows the weirs from contaminating the surrounding area.  

How Fine Material Screw Washers Work

McLanahan Fine Material Screw Washers wash, classify and dewater fine material. When a slurry feed enters the washer box of the unit, the heavier product-sized particles sink to the bottom of the machine, while lightweight material and contaminants (such as twigs and trash) float to the top of the pool area and are removed with the overflow.

The product-sized material is conveyed up the inclined dry-deck area by either one or two rotating spiral screw shafts. As the material is conveyed toward the discharge end, excess water drains back into the washer box, effectively producing a dewatered product.

In the oil field application, the McLanahan Fine Material Screw Washer will be utilized to recover the sand used in the oil wells so that it can be reused.  

Unique Design

“The design for this screw washer is unique,” said McLanahan Mechanical Engineering Design Specialist Mike Wahl. “It has a fully submersible lower bearing because the screw washer is in the box with the drilling fluid.”


This Fine Material Screw Washer features a submersible lower bearing.  

Usually, sand screws are installed on the ground or on a foundation, so the lower bearings are easily accessible when it comes time for maintenance activities. Because bearing access is restricted with the Fine Material Screw Washer being located inside the container filled with drilling fluid, McLanahan had to design the unit with auxiliary lubrication points. These auxiliary lubrication points are located higher up on the screw washer so that the customer can maintain the bearing while it is in the container. 

“I think what makes us unique is we do custom designs for customers,” said Wahl. “With the wide range of configurations we have, depending on their specific application, we can make changes that are best for them.”


McLanahan designed the Fine Material Screw Washer with auxiliary lubrication points for the lower bearing so that it can be maintained while submerged. 

The McLanahan Advantage

Besides McLanahan’s willingness to work with customers to ensure they get the right solution for their site, McLanahan’s Fine Material Screw Washers offer four distinct advantages over competing units.

First, they have a larger pool area behind the feed box, which provides a higher retention of fine (200 mesh) product-sized solids.

“The larger pool area allows time for fine material to settle, and when we do that, the customer can recover more material out of the machine,” Wahl said.

Second, McLanahan Fine Material Screw Washers are designed with a 2.5” (65mm) gap between the screw shaft and the washer box, which eliminates wear on the box.

Third, longer screw shafts and an extra-long dry deck area allow more time for the material to dewater, ultimately providing a drier product in comparison to others.

Fourth, McLanahan designs its robust bearing assemblies with Caterpillar Duo-Cone® seals to protect the bearing from water and fine particles, which increase the life of the bearing.

“Our lower bearing is designed for long life and low maintenance, and that’s always a good thing for the customer,” said Wahl.

These four differences are ultimately beneficial to the customer.

“They help the customer by reducing downtime so they can run longer, recover more materials and, in the end, make more money,” said Wahl. 

Need Some Help?

Our customer service team is here to help you 24/7. We can ship you parts, send field service technicians to your site and answer any questions you have. Whatever you need, we are here for you.