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Outdated technology often results in increased maintenance, which can quickly become costly. A cement plant owner had this problem on his bucket elevator. The analysis carried out by Beumer customer service shows that it is not necessary to replace the entire system, but only its components. Even if the system is not from Beumer, service technicians can upgrade the bucket elevator and increase efficiency.
“From the very beginning, our three bucket elevators caused problems,” says Frank Baumann, plant manager for a medium-sized cement company in Erwitte, North Rhine-Westphalia, near Soest, Germany.
In 2014, the manufacturer also opened a factory in Duisburg. “Here we produce cement for the blast furnace, using a central chain bucket elevator as a circulation bucket elevator for the vertical mill and two belt bucket elevators for feeding into the bunker,” says Baumann.
The bucket elevator with the central chain of the vertical mill was very noisy from the start and the chain vibrated over 200mm. Despite several improvements from the original supplier, heavy wear and tear occurred after only a short operating time. “We have to service the system more and more often,” says Baumann. This is expensive for two reasons: downtime and spare parts.
Beumer Group was contacted in 2018 due to frequent shutdowns of a vertical mill circulation bucket elevator. System suppliers not only supply bucket elevators and retrofit them if necessary, but also optimize existing systems from other suppliers. “In this regard, cement plant operators are often faced with the question of what would be the more economical and targeted measure: to build a completely new plant or a possible upgrade,” says Marina Papenkort, Regional Sales Manager for Customer Support at Beumer Explain groups. “Through our customer support, we help our customers meet future performance and technical requirements in a cost-effective manner in the context of upgrades and upgrades. Typical challenges for our customers include increased productivity, adaptation to changed process parameters, new materials, optimized availability and extended maintenance intervals , easy-to-maintain design and reduced noise levels.” In addition, all new developments related to Industry 4.0, such as belt control or continuous temperature control, are included in the modifications. The Beumer Group provides one-stop services, from technical sizing to on-site assembly. The advantage is that there is only one point of contact, which reduces the cost of organizing and coordinating.
Profitability and especially accessibility are crucial for customers, as retrofits are often an interesting alternative to new designs. In the case of modernization measures, as many components and structures as possible are retained, in many cases also steel structures. This alone reduces material costs by about 25 percent compared to a new design. In the case of this company, the bucket elevator head, chimney, drive and bucket elevator casings can be reused. “In addition, assembly costs are lower, so downtime is generally much shorter,” Papencourt explains. This results in a faster return on investment than new construction.
“We converted the central chain bucket elevator into a high performance belt bucket elevator type HD,” says Papenkort. As with all Beumer belt bucket elevators, this type of bucket elevator uses a belt with a wireless zone that holds the bucket. In the case of competitor products, the cable is often cut when installing the bucket. The wire rope is no longer coated, which can lead to moisture ingress, which can lead to corrosion and damage to the carrier rope. “This is not the case with our system. The tensile strength of the bucket elevator belt is completely preserved,” Papencourt explains.
Another important factor is the connection of the belt clip. On all Beumer cable belts, the rubber at the end of the cable is first removed. Technicians separated the ends into individual threads in the U-shaped part of the belt clip connection, twisted and cast in white metal. “As a result, customers have a huge time advantage,” Papencourt said. “After casting, the joint is completely cured in a very short time and the tape is ready for use.”
In order for the belt to run stably and have a longer service life, considering the abrasive material, the Beumer team replaced the existing segmented drive pulley liner with a specially adapted ceramic liner. They are crowned for stable straight running. This easy-to-maintain design allows quick replacement of individual segments of lagging segments through an inspection hatch. It is no longer necessary to replace the entire drive pulley. The lagging of the segment is rubberized, and the lining is made of solid ceramic or steel. The choice depends on the transported material.
The bucket adapts to the crown shape of the drive pulley so it can lie flat, greatly increasing belt life. Their shape ensures smoother operation and less noise. Depending on the intended use, the operator gets the bucket that best fits the design. For example, they can have a rubber sole or be made of quality steel. The proven technology of the Beumer HD impresses with its special bucket connection: to prevent large material from getting between the bucket and the belt, the bucket is equipped with an extended back plate that can be connected to the bucket elevator belts that are flush. In addition, thanks to HD technology, the bucket is securely attached to the back of the belt with forged segments and screws. “To break the barrel, you need to throw out all the screws,” Papenkort explained.
To ensure that the belts are always and correctly tensioned, Beumer has installed an external parallel drum in Duisburg that does not touch the product and ensures that the winding wheels are limited to parallel movement. Tension bearings are designed as internal bearings of a fully sealed design. The bearing housing is filled with oil. “Part of our HD technology is the easy-to-maintain grating rollers. The rebar is hardened by the delivered abrasive and screwed into the grating rollers for quick replacement. .
“This upgrade allows us to increase the availability of the vertical mill circulating bucket elevator and become more competitive in the long term,” says Baumann. “Compared to the new investment, our costs were reduced and we worked faster. In the beginning, we had to convince ourselves more than once that the upgraded circulating bucket elevator was working, because the noise level had changed a lot and we were not familiar with the smooth operation of the previous chain bucket elevator. elevator”.
With this upgrade, the cement manufacturer was able to increase the capacity of the bucket elevator to feed the cement silo.
The company was so excited about the upgrade that it commissioned the Beumer Group to optimize the throughput of two other bucket elevators. In addition, operators complained about constant deviation from the track, buckets hitting the wellbore and difficult service conditions. “In addition, we wanted to increase the capacity of the mill even more and therefore were interested in more flexibility in the bucket elevator capacity,” explains Baumann.
In 2020, the system vendor’s customer service is also addressing this issue. “We are completely satisfied,” Bowman said. “During the upgrade, we can also reduce the energy consumption of the bucket elevator.”