Plants can be old or new, transit mix or central mix, large or small. But they all have one thing in common: How well they are managed has a significant effect on their overall efficiency.
A simple definition of batch plant efficiency is the ratio of (a) the cost of inputs (employee hours, materials, energy, equipment, etc.) to (b) the revenue generated by sales of concrete. If you divide B by A and the result is less than one, you probably should begin planning your career change.
The most efficient batch plants produce more concrete with less wasted material, lower repair costs, less downtime, and fewer disruptions in employee productivity. Initiatives such as more thorough quality control, understanding customer needs, and installing and operating concrete recycling systems will reduce waste.
Every operation is unique, yet the managers of highly efficient plants focus consistently on five key areas: preventive maintenance, cleanliness, batch control, driver staging, and safety.
1. Practice Preventive Maintenance (PM)
Plants where some kind of formalized inspection and maintenance schedule is in place tend to have fewer breakdowns. If the plant manager recognizes the importance of regular PM and communicates that to employees, chances are good that noisy bearings, worn belts, leaky air systems, and clogged filter bags will be detected and repaired before breakdowns interrupt batching.
Also, be sure to:
- Stock critical plant parts such as solenoid valves, air cylinders, bearings, and various repair kits.
- If you are not sure what spares are on hand, sit with your head of maintenance and develop a list. Your concrete equipment dealer can help with this list as well.
- Keep your parts area neat and put labels on shelves.
- Organize v-belts for easy access.
Computers are great at watching the calendar and reminding you what to do.
Set up a maintenance program using PM software, either stand-alone or as part of your batching software.
For example, some batch control manufacturers offer an integrated PM scheduler. You can use time or yardage as basic parameters by which to measure work done and set schedules. This provides a great way to track parts and equipment and can help with spotting failure trends and recovering warranty reimbursements to which you could be entitled.
2. Keep Things Clean
Keeping a plant clean is a constant battle. Abrasive dust is especially hard on solenoid valves and cylinders. Add a little moisture, which mixes with the dust to form a crust that's hard to remove, and you have a mess that hinders maintenance and inspections.
What causes some plants to be dirtier than others? Visit half a dozen plants owned by the same company and you will find some are messy and others clean. The only significant variable is the person in charge of running it. Good housekeeping goes hand-in-hand with regular maintenance, so it is usually a safe bet that the clean ones are more efficient. Stopping at midday to hose out a mixer makes more economic sense than chipping out concrete once a month. The mixer and liners also will last longer.
Specifying the right equipment is also important. A truck loading dust collector keeps the plant cleaner, and truck drivers will spend less time washing down the truck after loading.
An air dryer will increase your filter bag change interval and keep your compressed air system clean on the inside. Follow basic air system maintenance to minimize leaks. A poorly maintained system can lose 20% or more of its air to leakage, and mechanical energy generated by compressed air costs seven to 10 times more than electrical energy.
If you're in the enviable position of buying a new mixer for a central mix plant, consider a horizontal reversing mixer such as the CON-E-CO HRM-12 or similar Canadian mixers. Quiet running, with no tilt hydraulics, no main ring and pinion to lube or adjust, considerably less dust due to sealed inlet and discharge openings, and no splash during mixing, they reduce both cleanup and mechanical maintenance.
Finally, a drive-through truck wash system can be a big time-saver. Whether you buy one from an established truck-wash vendor or build your own, these systems can boost plant efficiency. One producer in Maryland built an automated system equipped with an electric eye that starts a pump when the beam is broken, pushing water through plastic pipe drilled with strategically placed holes.