As one of the largest producers of bagged cement, ready mix concrete, and concrete block in the United States, Rinker Materials Corp provides a diversified offering of construction and building materials, including cement, aggregate, brick, glass block, reinforcing steel, construction chemicals, drywall, and fireplaces. So maintaining an efficient operation is key. When Rinker needed to increase productivity at its Port Everglades, FL cement terminal, Thompson Scale Co provided the solution.
The Challenge
To improve the efficiency of the Port Everglades terminal, Rinker needed a system that would help its packaging process run more smoothly and produce bags that were even closer to target weight goals, while providing the safest environment possible for employees. A 3-phase plan was chosen: an in-motion checkweigher (phase one), data collection software (phase two), and a packer upgrade (phase three).
Normally, heavy-duty checkweighers require about 4 ft of linear space to weigh a bag properly. But Rinker had only 3 ft of available space in the existing conveyor line. This space also had to accommodate a product rejector powerful enough to remove off-spec bags from the production line. Obtaining accurate bag weights was a challenge because the immediate slope at the infeed of the bag flattening incline conveyor caused the bags to create a downward force on the checkweigher as they went up the conveyor, potentially altering the bag weights.
Said Juan Alvarez, terminal manager at Rinker Materials, "We only had a small amount of space available between the turning conveyor and the bag flattening conveyor. This made the addition of a checkweigher more difficult."
It became clear that data collection and analysis would be needed to assist in targeting optimum bag weights. The challenge here was that the management office is in a different building from the packing warehouse -- and the road between the two buildings is a heavy traffic area for semi-trucks. Any cables would have to be hung high overhead or dug into the ground, which would be expensive.
Finally, Rinker's St. Regis 150 4-spout impeller packer, with each spout on close centerlines, presented several engineering challenges. The load cell flexure assemblies would have to fit into an extremely restricted access area with spouts on very close centerlines. A fill spout and product cut-off assembly had to be designed that would place the fill spouts in exactly the same position as the old mechanical system, allowing automatic bag placers and take-away conveyors to be used without modification. A product cut-off assembly would also be needed to eliminate product spillage, yet keep the fill nozzle and spout from plugging between fills.
Thompson Scale, in conjunction with Choice Bagging Equipment, had already developed and successfully installed electronic upgrades in Rinker's sister plant in Miami, as well as several other companies within the same industry. This made them the right vendors for the current upgrade.
TSC Solutions
Thompson Scale and its wholly owned subsidiary, Telemetry Solutions, have provided a complete solution, including installation of a 4693 Heavy-Duty Checkweigher and StatPak-PC real-time data collection and reporting software, along with an upgrade of Rinker's St. Regis 150 cement packaging machine.
Heavy-Duty Checkweigher
Thompson Scale met the lack-of-space challenge by designing a unique compact checkweigher with a space-saver reject ram. The smaller-sized 4693 Heavy-Duty Checkweigher still provides the same accuracy, features, and functionality as a full-sized unit, along with extremely fast weighment cycles to meet the application requirements. The innovative reject device is built onto a support isolated from the scale, yet places the reject pusher plate directly at the discharge end of the scale. The plate is suspended from an oversized rodless cylinder capable of ejecting an off-spec bag and returning to the "home" position before the next bag enters the scale -- even at high production rates.
Crucial to the installation is a photo-eye attached to the 4693 Heavy-Duty Checkweigher, which allows for more accurate weighing in such a tight space. This also assists in the bag reject system by obtaining the weights more quickly than normally possible.
Another feature of Thompson Scale checkweighers is their easy-to-use controllers. "The checkweigher controller is very simple for our operators to use. There are even additional functions available that we could also use if needed," Alvarez stated -- options such as settable filters, storing 75 different product types, displaying errors for mechanical and system faults, as well as bilingual menus.
"We have another terminal in Miami that has a couple of checkweighers installed and they are very pleased with their performance," says Alvarez. When asked what first inspired Rinker to look for a checkweigher, he replied, "We were looking to increase our production rate, while another main reason was safety. We were using manual labor to get the weights of the bags. This required us to stop the process and have someone pull a bag and put it on a scale to check the weight. We were checking bag weights every 30 minutes, which was harder for our workers and took away from production time."
StatPak-PC Real-time Reporting
For real-time data collection and reporting software, Telemetry Solutions' StatPak-PC system's concise design and powerful reporting tools allow users to easily view production data on a PC, so they can quickly and easily adjust production to optimal levels and analyze production flow over a period of time. Yet the system is much more cost effective than competitive systems.
When asked why they decided to collect weight data, Alvarez replied, "We installed it to double-check the paperwork that the bagging employees submit by comparing it to the production rates we show in the system to monitor performance in the terminal."
The software proved easy to install, configure, and use. Thompson Scale's engineers set up a wireless modem to transmit data to the management office in a different building without incurring additional expenses of running cable. Despite the heavy truck and plant radios used throughout the day, the production line data was flawlessly received in the office, without running any wires.
StatPak-PC monitors 100% of production in order to track production rates. "We bag throughout the week, and every day that we do bagging, we monitor production rates at the closeout by running a report from StatPak-PC," Alvarez stated.
Everyone, from line operators to experienced production supervision and corporate management, has access to the information they need to help them make more informed decisions.
Packer Upgrade
Thompson Scale upgrades filling machinery from counter weights and manual controls to a system with automatic controls and a load cell, for more efficient use of older technology. Choice Bagging Equipment was involved in the design of a number of mechanical parts, mechanical fabrication, installation, and startup of the filler upgrade. Another firm assisted with upgrading the existing bag placing equipment. Thompson Scale provided the controls and technology to complete the upgrade process.
Why did Rinker choose to upgrade its packing machinery versus buying new machines? "The terminal in Miami upgraded their packing equipment first, which worked well, and the equipment is almost maintenance free -- that made our decision real easy," says Alvarez. Thompson Scale designed a system for Rinker that was extremely easy to maintain, with few wear parts and quick changeover of replacement parts. As to the actual installation, Alvarez had this to say: "The installation went smooth and there weren't any major issues. Three different companies worked together to upgrade our equipment and everything worked out great."
The Results
Heavy-Duty Checkweigher: Rinker has experienced many benefits since installing the 4693 Heavy-Duty Checkweigher. "The main improvement is our increased bag per manhour rate, which has gone up over the last couple months. Now, we can constantly monitor weights without having to stop the operation," Alvarez says.
"The other important aspect is safety -- the risk of injury is reduced. Our employees enjoy the improved safety and have more comfortable working conditions by not having to handle the bags to weigh them. Also, if we have any reject bags, the checkweigher rejector pushes them off the conveyor without someone having to handle the bag. Our production is faster and safer and we have really noticed the increase in our cement production rate," he added.
StatPak-PC Real-time Reporting: StatPak-PC allows Rinker to quickly and easily adjust production lines to even better levels, resulting in more efficient production. "We track and monitor production through the data we get from the StatPak-PC system. I can see a production increase happening on a monthly basis. We can also track inventory better through the computer and analyze data such as number of bags per minute, total weight, and any variance. The reports we generate are really helping us in monitoring the terminal.
"The software helps us maintain a constant quality and weight on the bags. This accuracy also makes the appearance of the bags on the pallets look even better," Alvarez added.
Packer Upgrade: "The number one thing is a significant increase in production," says Alvarez. "Before, our filling time was 12-15 seconds per bag. We operate at 8 or 9 seconds now, which has really increased our overall production. Another bonus is that only one person has to run the bagging equipment since it's automated. Now, the system can be run with one operator that can see the automatic bag placer at the same time as the controller and easily check the weights of each bag. This has saved us a lot of manhours. Along with that is improved safety: our employees do not even have to be near the conveyor belts anymore."
In addition, Alvarez pointed out that almost no maintenance is required, and simpler calibration can be done in-house, rather than by an outside contractor. Product spillage at the spouts, which was a problem in the original St. Regis 150 design, has been almost 90% eliminated, reducing dust in the area and greatly reducing reclaim.
Summary
Asked how long it might take to reach an ROI and justify the expenditures, Alvarez responded, "We did a quick study that showed an increase in production while there was a sharp decrease in labor and maintenance. It's significant enough that we should see a return on investment within a relatively short time."
Summing up the installation and Thompson Scale's products, Juan Alvarez stated, "It was a very good experience. I will definitely recommend Thompson Scale."
