Eugene, OR: Raw Material grinding is among the core operations in a cement plant and is oftentimes, configured to feed into a vertical roller mill (VRM’s), which is the preferred choice in most North American cement plants. An overlooked part of the mill system is oftentimes the feeding device responsible for consistently transporting materials into the mill. Today, the majority of the raw mills in North America are fed with large-capacity rotary feeders similar to the PMCA rotary feeder manufactured by Precision Machine & Manufacturing. Referred to by European mill manufacturers as a “rotary sluice,” the rotary feeder has a pair of very important functions. Firstly is maintaining efficient feed rates. In most operations, a variable speed belt pulls the raw materials from the storage location and also establishes the basic tonnage feed rate for the mill. The rotary feeder fine-tunes the feed rate by discharging a specific volume of material into the mill with each revolution of the rotor. Consistent feeding leads to a uniform bed-depth in the vertical roller mill (VRM), which provides effective, uniform grinding. The secondary function of a rotary feeder in a raw mill application is to act as an airlock, which minimizes false air introduction into the milling process. The importance of a high-quality airlock is two-fold: First, it creates conditions inside the mill for efficient, uniform grinding and it minimizes fan horsepower, requiring less energy.

Two years of operation between rebuilds– Most competitive raw mill material feeders require regular ongoing maintenance and adjustment, which oftentimes leads to a major rebuild during the annual outage. Precision’s PMCA raw mill rotary feeders turned the industry upside down by eliminating rebuilds at every annual outage! In fact, we can confidently boast that Precision Machine & Manufacturing PMCA rotary feeders are able to operate for up to two years without a rebuild! In addition, in some applications, we believe three years of operation between rebuilds is very possible under the right conditions.

Avoiding the cost of a rebuild every year saves Plant Managers up to $100K a year in capital expenditures.

Reduced false air induction– False air induction can wreak havoc on a raw mill material delivery system! Precision Machine & Manufacturing’s process allows PMCA feeders to be built with rotor-to-barrel clearance of 0.045” to 0.075” per side, depending on the size of the feeder. These industry-leading tight clearances reduce false air introduction by thousands of cubic feet per minute, which also eliminates premature wear of components!

Low or no recurring maintenance costs! Precision Machine & Manufacturing’s PMCA feeders are designed to cost less over the lifespan of the feeder! There are no adjustable rotor tips, flap diverters, removable sides, or other maintenance-intensive items to worry about. It is really as simple as installing the feeder, starting it up, and going to work! Maintenance Requirements? Very slight maintenance requirement needed! We recommend bi-monthly lubrication of the bearings and a semi-annual inspection of the wear plates. Otherwise, less is more!

Most customers get two rebuilds out of every Precision PMCA Feeder! Proudly Made in the USA!

Technical Evaluation Service: Every PMCA Rotary Feeder manufactured by Precision Machine & Manufacturing is automatically enrolled in our own Technical Evaluation Service (TES), which is the only service of its kind in the industry! All rotary feeders enrolled in the TES program receive one to two onsite inspections per year, which allows Precision personnel to closely monitor the feeder’s operation and address any problematic areas in advance of a catestrophic failure. The TES service is just one more way that Precision Machine & Manufacturing is working to ensure that every customer is maximizing their return on investment and getting the very most life out of every PMCA rotary feeder!

Our job is to keep your plant working and we do everything within our power to ensure it does!

Made in the USA: Every feeder, valve, and screw conveyor that we manufacture is truly made in the United States of America! We start with domestically sourced raw materials and we build every unit from scratch! Choosing Precision Machine & Manufacturing is much more than choosing a rotary feeder, valve, and/or screw conveyor. You are hiring men and women that are active in our community and consist of military veterans, youth coaches, volunteer firefighters, mentors and we even have one National Champion!

Proudly Made in the USA!


More Posts You May Find Interesting

Let our applications specialists
help you with your extreme-duty
bulk material handling needs.


With your toughest material handling challenges