The cement industry’s requirements are undergoing a major change: The volume of cement produced is no longer the only focus, but rather the demands for clean filling and a consistent quality of the manufactured product are rising continuously. At the same time, manufacturing costs need to be reduced and profitability increased. Improved efficiency must neither come at the expense of the environment, nor the employees’ health.
The Haver & Boecker Radimat® is a very important element in rounding out the packing workflow. The Radimat bag applicator automates the packing of cement into valve bags using rotating packing systems. It can use empty valve bags from a bundle or from a roll. The bags are mechanically shot onto the filling spout of the packing machines and adapted to their speed. This makes the packing process independent of the machine operator’s work quality. The Radimat achieves a shot accuracy rate of up to 99.7 %, thus allowing the packaging machine’s maximum performance to be fully exploited.
Greater capacity utilization
Today the decisive question that plant operators have concerning nearly every investment is: What is the payback time? The following is an example calculation for a fully automatic bag application with a Haver & Boecker Radimat: Assuming the automatic machine continuously feeds 120 bags per hour more than by manual bag application, i.e. two bags more each minute, this amounts to 240000 additional filled cement bags annually for a plant operating 8-hour shifts, 5 work days per week and 50 work weeks per year. Two hundred and forty thousand bags, 50 kg each, mean an additional production of 12000 t of cement into bags. With an assumed margin of 10 % per ton, the investment pays for itself within a year.
A study by Haver & Boecker even shows far more positive figures. Three, 8-spout Roto-Packer® lines of one customer were equipped with software for a study that calculated the ratio of actual to maximum bag application. For manual bag application, the ratio was only 69 %. On the other hand with the Radimat automatic bag application, it was over 99 %. Once the three lines were retooled, they achieved over 300000 t more production each year because the fully automatic bag application operated 3 shifts per day. The use of a Haver & Boecker Radimat paid off in hard cash within a very short time.
Haver & Boecker Radmiat components
The Haver & Boecker Radimat consists of the bag applicator unit and the empty bag feeder. The empty sack magazine can hold from 225 to 2000 empty sacks, depending on the required capacity and length.
As an option, the Haver & Boecker Radimat can be equipped with a rotary table. This is placed between the empty bag magazine and the bag applicator unit and thus ensures greater flexibility in system planning because the machine installation can be easily adapted to the building situation. This advantage often comes to the fore when retrofitting.
Alternatively an empty bag roll system with up to 4000 bags per roll can be used. Here the Radimat works continuously and the operator is only used for roll changing. A double roll magazine almost completely eliminates possible dead times because there are no production stops for roll changes. Personnel are hardly tied up when using this type of empty bag feeding.
A system for all bags and product types
When developing the Radimat, the experts at Haver & Boecker deliberately focused on developing countries and emerging markets, where bag types of poor quality are primarily used. As a result, the Radimat was specifically designed to handle different bag types with different dimensions. They are as follows:
Glued bags/box-shaped valve bags
single or multiple ply paper bags
single or multiple ply woven WPP bags
Sewn bags/standard valve bags or without side gussets
single or multiple ply paper bags
composite bags of woven and paper layers glued to each other
highly flexible single ply woven bags of poorest quality (typically seen in India or China)
Naturally the operational availability of the machine increases as bag quality increases, Haver & Boecker advises on the choice of bag type, and provides support in setting the packing process.
The Radimat is suitable for systems that pack a wide variety of loose, bulk materials with different specific weights. For this reason the Radimat has been developed for special requirements with regard to developed markets. It handles Seal bags or valve bags with a pulled out valve, various weight sizes, bag formats and bag bottom widths.
Improved work conditions
In addition to improved production plant capacity utilization, “soft factors” also play a key role in the decision to further automate plants: new investments for process automation must always meet the increased demands on the health, safety and work conditions of machine operators.
The Radimat makes a significant contribution to reducing medical costs and improving general working conditions in plants with extremely poor working conditions, which are particularly prevalent in countries with low wage costs and poor bag quality. This point is particularly important in developing and emerging countries where work conditions and packaging materials are extremely low in terms of quality.
Work conditions for machine operators improve considerably when using a Radimat because the operator’s work position is moved to an area with low dust levels. With manual bag application, the machine operator is very close to the filling spout and thus can come into very close contact with the cement in the event of defective bagged goods. “If an empty bag bursts at the filling spout due to faulty manufacture, e.g. poor gluing, there’s a lot of dust and the employee is right smack in the middle of it,” says Andreas Halfar, Sales Manager at Haver Cement. This is a considerable dust exposure and hardly justifiable for health reasons. On the other hand, with the fully automatic Radimat bag application, the operator stands in a position where he is barely in contact with the product. In addition there is no danger from the mechanical system. Moving the work area thus offers clear safety and health advantages.
The actual work itself even becomes more pleasant. The machine operator is under enormous stress when he applies bags manually. The machine sets the cycle rate and the operator has to keep up. In general a rate of 2 400 bags/h is regarded as the limit. However, experience has shown that the performance of manual bag application drops by up to 35 % over the entire operating time of a work shift. All inattentiveness and errors have a direct negative impact on the system’s performance. Often two operators share the workplace: one does the preparatory work and the other puts the bags on. This process is usually carried out in a rotating manner in order to carry out the steady work of applying the bags with the needed concentration. Using a Radimat makes this work more flexible and, above all, independent of the system cycle. The empty Radimat bag magazine is manually filled with bags to provide a supply and the machine operator can keep a better eye on the filling process and entire packing line with the time that is freed up. If the system is designed accordingly, the operator can even operate several lines simultaneously or take on other tasks.
Operating high performance machines profitably
In reality the already mentioned top limit of 2400 bags/h can hardly be achieved with manual bag application. Today in the cement industry, however, capacities of 4000-4500 bags/h are the order of the day. Even capacities of up to 5000 bags/h are reached in individual cases. These values are unthinkable using manual bag application - even with two machine operators. Especially in highly developed markets with a decreasing share of bags, the use of a Haver & Boecker Radimat means that systems can be operated economically with one machine operator in a single shift and with maximum savings in personnel costs.
One example: Germany today has a bag share of approx. 8-10 % of the total cement market. To avoid overcapacities, packing plants are already merging. When using a Radimat, a correspondingly high performance system pays off in that the operating and personnel costs incurred can be kept to an absolute minimum.
The Radimat automatic bag applicator has not only been designed for the Haver & Boecker Roto-Packer, it can also be retro-fitted to all rotating packing machines currently on the market and thus be used to optimize packing processes. The Radimat can be installed in existing lines or for making new lines more compact in two or three dimensions. Components such as rotary tables, elevating systems and different magazine arrangements can be set up in a variety of locations. This can lead to considerable savings in personnel and space – especially in large systems where the empty bag magazines are set up directly in the bag storage area. In particular, this advantage comes into play when retrofitting “installed”, old systems.
Retrofitting with a Radimat is not only about speeding up bag application, but also about optimizing the overall system. Some control units such as dosing time controllers or fine flow controllers regulate core processes during filling and packing. They require a certain ramp-up time to find the optimum setting. When applying bags manually, there are frequent process interruptions and so these controllers always need to be reset. Because the Radimat runs at a monotone rate and prevents interruptions, it ensures a perfect flow for the entire packing line.
The Haver & Boecker packing experts observe and analyze all steps, components and process parts at the packer. “We make a variety of adjustments to reach the optimum. For example we may recommend a different bag quality to the customer, a different process sequence, or training of plant operators and maintenance personnel,” says Klaus Siewecke, Haver Service. The aim is to reduce downtime, eliminate rejects and increase performance. The Haver Quattro System Monitoring is often used in addition. It records the difference between manual bag application and automatic application using a Radimat. It documents the increased performance “in black and white”.
Retrofitting a packing plant with a Radimat is one of the classics of the Plant Optimization Plan (POP) offered by Haver & Boecker. In this optimization process, Haver & Boecker engineers look at the customer’s entire line - from product infeed from the silo and on through packing, bag transport, palletizing and to loading. They analyze the current status, check for possible improvement potential and develop a holistic optimisation plan. Siewecke sums it up: “We make the plant fit for the future.”