Steel belts: Important efficiency results

Steel supports sustainability

Sustainability efforts comprise numerous aspects, with opportunities for improvements big and small in many nooks and especially crannies, which all add up. Steel belts for baking ovens are able to provide some of the most visible efficiency results in this regard. Berndorf Band Group and IPCO show how that’s done.

+Baking ovens can account for as much as 45% of a bakery’s overall energy consumption; of this, as much of 25% is used to heat the conveyor belt, which is why maximum efficiency is not only recommended but necessary, as it can have a major impact on overall energy costs. Moreover, “Solid steel belts are inherently lighter than mesh belts – perforated belts even more so – and this translates into significant advantages in terms of energy efficiency,” Marko Leber (Global Product manager, Food – IPCO) highlighted this for us, pointing out two main reasons: a lighter belt means less steel to reheat with up to 30% less energy required. Lower weight also means less power is needed to ‘drive’ the belt through the oven.

Energy efficiency is becoming increasingly important for the industry. “The new oven technologies coupled with our highquality steel belts enable such efficient energy recovery,” explains Thorleif Brokke, director sales, Berndorf Band Group. To maximize efficiency, the Austrian company recommends periodic inspections of the steel belt and belt system to keep everything clean and replacing parts that wear such as scrapers, brushes, supporting elements, etc. “Furthermore, preventive cleaning is always advisable, to avoid heavy pollution of the belt and to save costs and time,” Brokke suggests.

And that’s not all; as a conveying medium that’s completely flat and smooth, a steel belt has the major advantage of having no gaps, recesses, or crevices in which carbon deposits could collect. This makes them inherently quicker and easier to clean than mesh belts. “As well as minimizing the risk of harmful acrylamide build-up, the ‘cleanability’ of a flat belt means less water consumption, reduced use of chemicals/detergents, and – depending on the cleaning method – less energy expended on heat,” Leber explains.

Time is money

Berndorf Band Group are also noticing a trend among baking oven manufacturers towards wider and longer baking ovens, for high-capacity production. Besides, “The ovens are manufactured to facilitate maintenance of the internal parts of the machine. This also has a positive influence on the lifespan of our steel belts, as these modifications also facilitate the maintenance of the steel belts,” adds the specialist from Berndorf Band Group.

Steel-grade oven belts are guaranteed to preserve their properties over years of operation; the special heat treatment process to which the steel belt is subjected gives it optimum tensile strength and perfect surface quality. Brokke says: “The premium-quality belts of Berndorf Band Group retain their flatness and shape even with fluctuating operating temperatures and a high number of load cycles.” Heat must be evenly distributed across the entire width of the belt; in addition, even belt allocation ensures a smooth production process. “As a result, the belt does not change its properties

© Berndorf Band Group

Berndorf Band Group steel belts

The CARBO steel belt is the company’s core product as it can withstand the high loads of mechanical and thermal stress that typically occur during the production of baked goods. CARBO 13 has an excellent temperature conductibility, and operating temperatures of up to 400°C/750°F during the baking process. Berndorf steel belts for the baking industry are available in widths from 800mm to 1,500mm. Other dimensions are manufactured upon customer request. The company also supplies components such as belt tracking systems, graphite bars and skid bars, as well as guiding and supporting sheaves.

due to different temperature stresses on each side,” Berndorf’s specialist summarizes. The company’s CARBO 13 steel belts are built to withstand temperatures of up to 400°C/750°F, making them suitable for every baking process of the industry.

On the other hand, durability is one of the most important qualities of the steel belt. “The steel itself is selected for its strength and wear resistance, and our manufacturing processes are designed to optimize long-term performance. […] It would not be overstating things to say that it is virtually unheard of for a steel bake oven belt to reach ‘end of life’ due to fatigue stress,” adds Leber. IPCO manufactures solid and perforated steel bake oven belts in a steel grade known as IPCO 1100C, “A hardened, tempered carbon steel selected for a unique combination of properties that include a hard, smooth surface for easy cleaning, very good fatigue strength for long term reliability and very good thermal properties too, which equates to efficient baking.” The result is a conveying medium with good tensioning and tracking characteristics and excellent resistance to stretching; this means that a belt life of 20 or more years is not unusual.

Steel belts have a higher initial investment cost compared with mesh belts, but their longevity and lower maintenance requirements make their total life cost worthwhile. “And a long working life – maybe four to five times longer than that of a mesh belt – is obviously the right choice from an environmental point of view too,” emphasizes IPCO’s specialist.

Maintenance is also key to the life span of a steel belt. One of the most important aspects of belt maintenance is the application of an appropriate lubricant. This minimizes friction, reduces wear on skid bars, prevents belt distortion and ultimately leads to longer belt life. Another benefit is that it helps to maintain a regular belt color for a more even bake. “We strongly recommend installing graphite skid bars. These deliver a gradual deposit of graphite to the inside of the belt, reducing friction and helping to eliminate the risk of rust caused by condensation,” IPCO also recommends.

Hot and cold

Steel bake oven belts maintain their properties over years of operation through thermal stresses of constant cooling and re-heating to temperatures as high as 400°C. Issues anywhere in the system can have an impact on how straight and flat the belt is. “For instance, wavy belt edges can be a sign of uneven temperature in the oven, or an indication of side wandering caused by dirty, worn, or ill-adjusted drums, idlers, skid bars or break points. Edge burrs are a sign of the belt coming into contact with the structure of the conveyor, a clear sign that something in the system is not operating as it should,” explains Leber (IPCO). In case the steel belt does suffer damage, it can usually be repaired fairly easily, extending its working life and adding to its credentials in terms of sustainability. If there is a problem with the belt edge and the root cause is identified and rectified, the belt can be trimmed if necessary and then filed to a round finish. If there’s a crack at the belt edge, a crescent-shaped piece can be cut out and the edges filed so that they are round. If the crack is within the belt, small holes can be drilled at each end of the crack to prevent it from spreading. And if more serious damage occurs, the damaged area can be cut out completely and a new piece spliced in.

To extend the lifespan of the steel belt, tracking problems should be consistently monitored and corrected as soon as possible. Belt tracking systems from the Berndorf Band Group are therefore recommended from the start of the implementation of the steel belt. “After the machine has been

IPCO steel belts

IPCO can produce solid and perforated steel bake oven belts to virtually any length and in widths from 800mm to 3,500mm. The company has a global sales and service operation with offices in more than 30 countries. This local presence is supported by a global engineering team, enabling IPCO to provide oven builders and end-users with technical advice, system solutions based on a comprehensive range of conveyor components, and a responsive repair/maintenance support service designed to maximize oven uptime. given a thorough inspection by one of our experts, we will compose the most suitable system and install it within a few weeks. Our experts can also advise customers on their existing systems,” Brokke (Berndorf Band Group) details.

Good practices: maintenance and cleaning

Steel belts in the baking industry theoretically do have an infinite lifetime; but, this is seldom achieved since some important points are routinely overlooked. “First and foremost, regular maintenance in connection with wellworking tensioning and tracking systems or belt cleaning systems is essential. Also, factors such as belt deflection, the summary of stresses, mechanical wear caused by belt touching elements, corrosion and the process itself must be taken into account for the limitation of the belt’s lifespan,” Brokke prioritizes.

During inspection, it is crucial to monitor the belt surface (inside and out), belt edges, flatness (checking for dents, distortion lines, waves, etc.), belt touching components and cross curvature regularly, to detect any damage and repair it before it develops further. Damage on the belts indicates issues with the machine, the tracking, the temperature distribution, or the maintenance, which should be identified and eliminated to avoid further problems, in Berndorf’s experience. The most common damage arises at the belt edges. Such sharp edges can be repaired with a simple re-rounding of the damaged belt edges before a more serious problem occurs, such as cracks.

The company also recommends cleaning the endless belt and the drums with scrapers, to prevent debris, product, or dirt from getting between the belt and the drums, which would cause belt damage. The inner side of the belt is normally cleaned with a plough and the product side with rotating brushes. To prevent the brushes from influencing the belt tracking, counter rollers must be attached to the brushes. Alkaline cleaning agents are recommended for further cleaning of the belt to remove product and dirt. Cleaning, in turn, can impact the environment; the priority toward eco-mindfulness is prevalent nowadays and the use of aggressive cleaning agents is an issue in the baking industry, Berndorf observes. Solid steel belts such as those supplied by Berndorf Band Group are much easier to clean than wire mesh belts, for example, meaning that fewer cleaning agents are required. This has a positive effect on the environment.

Brokke emphasizes: “In order to keep the belt in good shape, preventive maintenance of the machine and steel belt is essential. For this reason, we recommend checking the belt surface regularly, to avoid damages of the belt edges and to keep the machine and the belt clean.” Planned inspections of all belt touching parts are also necessary, to avoid the wear of the steel belt, and ultimately to extend its life. +++