Image
Remote ticketing systems increase a batch plant's efficiency by keeping drivers out of the control room.
Image
A central grease manifold eliminates the need to apply grease at the bearing
3. Optimize Batch Control

Out of all the processes in a dry batch plant, the one most critical to overall speed is control of the batching process as it affects the speed of the ribbon discharge into the truck.

There are many different ways to sequence water, aggregate, cement, and sand into the mixer, but the crucial issue is to find the optimal discharge speed to make mixing more efficient.

The obvious benefits of avoiding stopping the batch process is that proper ribboning of the materials into the mixer will shorten the driver's time to assure the batch is properly mixed and adjusted for slump.

The plant has choke points as well. A tip switch on the end of a chain is used inside the collecting hopper at the end of the mixer-charging conveyor at many high-production plants. If material buildup occurs, the rising pile tips the switch and stops the conveyor, saving costly cleanup time.

Monitoring choke points with a video camera has become standard practice at many plants, due to dropping system prices, the ease of stringing cat 5e cable, and high resolution of the latest color cameras. It doesn't take more than one prevented accident to pay for the entire system.

4. Stage Drivers More Efficiently

Plant operators often complain, “We could get more trucks through here if we knew where our drivers were.” Truck drivers naturally like to take a break from the confines of a cab, but wasting time tracking them down wreaks havoc on efficiency. Multiply five minutes by 20 drivers, and you can easily lose more than an hour a day.

Driver education and rules enforcement minimize these losses. Also, many plant operators have installed pneumatic ticket delivery systems or paperless ticket systems that send ticket information via Wi-Fi directly to the truck cab as part of an overall solution.

Remote ticketing systems have the added benefit of keeping drivers out of the control room, a fond wish of many batch plant operators. Another way to do that is to set up a driver lounge area away from the control room.

LED “billboards” at many plants signal for the next truck. Some producers even invest in wireless ticketing systems to keep the driver in the cab.

5. Plan for Safety

When designing your batch plant, you must select cost-effective equipment, but when specifying safety features, keep the big picture in mind. Employees working around conveyors, aggregate gates, and electrical panels are exposed to potential injury. This translates to downtime and legal liability.

Every plant's safety features should include emergency pull-cord shutoffs and safety disconnects on conveyor and turn-head motors, and confined entry access manholes in aggregate and cement bin compartments. Where possible, choose stairs with handrails rather than ladders. Ladders don't allow workers to safely carry tools and equipment to the area where they are working, which can contribute to that area not being serviced routinely.

Carrying this point one step further, certain kinds of automation can keep workers from harm's way. One example is a central grease manifold, which reduces employee exposure to dangerous areas by eliminating the need to apply grease at the bearing.

As mentioned, video observation systems provide a similar safety benefit by letting employees monitor choke points from the safety of the control room.

Safety planning generates efficiency by eliminating losses. To take a further step toward safety, read OSHA's Lockout/Tagout (LOTO) standard, which protects employees from injury due to unexpected startup while cleaning or maintaining equipment. Visit www.osha.gov and search for LOTO. You'll find a great deal of information, including a tutorial and case studies.

While this by no means addresses all aspects of batch plant efficiency, you can take your operation to a new level with a long-term focus on these five basics. Take it from an old timer—this stuff works.

— Jay Robinson is president of Mid Atlantic Concrete Equipment of Lititz, Pa. E-mail him atjrobinson@maconcrete.com, or telephone 888-378-6210.