Bake more, bake better, bake greener
IPCO is the world’s largest manufacturer of solid and perforated bake oven steel belts, designing and supplying efficient conveying solutions to oven builders and end users, and supporting them through a global service network. And the company has been doing this since the 1920s.
IPCO’s level of experience is unparalleled, and it qualifies them to provide advice, consultancy and support to machine builders and bakeries around the world.
A steel bake oven belt is an extraordinary tool: no other material offers such a broad range of qualities. Not only does it deliver reliable operation in applications where temperatures can reach as high as 400°C, but it does so with outstanding reliability; a 20+ year working life is far from unusual.
And as Staffan Karlsson, IPCO’s Global Marketing Manager for Belts, explains, a bake oven belt offers a number of other key production benefits too.
“For many users, the major benefit of steel bake oven belts is their versatility: they can be used for products as diverse as biscuits, brownies, crackers, pastries, energy bars, part baked bread, sponges, all-butter cookies, pizza bases and more. This factor alone has convinced a number of major bakeries around the world to upgrade from mesh belts, enabling them to broaden their ranges and enter new markets.”
Low maintenance means more production
Low maintenance and a long working life are important factors too. It is virtually unheard of for such a belt reach ‘end of life’ due to fatigue stress. During the baking process the steel belt is placed under considerable thermal stress as heating and cooling takes place every time it completes a revolution. A combination of steel belt grade and special manufacturing phases is used to achieve the necessary thermal properties of the material. These properties give steel belts the durability to operate for decades under what are severely challenging processing conditions.
And in terms of maintenance, qualities such as good tension and tracking characteristics and resistance to stretching result in significantly less downtime compared with other belt materials, important considerations when even an hour’s lost production can be costly.
There’s another way in which steel belts can help deliver production enhancements, and it’s one that a growing number of companies around the world are recognising.
“We are able to manufacture bake oven belts more than three metres wide,” said Karlsson. “This requires advanced manufacturing techniques in order to weld two or more belts together along the full length. The benefit is that bakeries are able to improve productivity without having to invest in factory extensions or new facilities. Upgrade from an 800mm belt to a 1500mm belt and productivity is virtually doubled without extending the line length. Choose a 3200mm belt and throughput is increased fourfold!”
IPCO has produced wide belts for use in bake ovens across Europe and in both North and South America. The largest to date, supplied to a customer in Scandinavia, was an impressive 3570mm wide. Most are used for biscuit production but other applications have included sponge cake and part-baked bread.
As an aside, while not designed for use in bake ovens, IPCO has actually produced steel belts as wide as 9000mm!
Solid steel belts for real butter cookies
“Bake oven manufacturers and end users have a number of choices in terms of conveyor type,” advised Karlsson, “and practical issues will be the #1 decision driver: if your product has a high fat content, you need to bake on a solid surface.”
This factor alone is one reason why IPCO belts are used the world over. While people continue to enjoy their favourite national and regional biscuits and crackers, the world simply cannot get enough of American-style cookies.
“These products use real butter, and often chocolate chips too, so need to be baked on a solid belt to eliminate the risk of melted product dripping and causing a fire, or simply drying out. The use of a solid steel belt also produces an attractive crisp base.”
This globalisation in taste has led a number of bakery operations to switch their facilities from wire mesh to solid steel systems. For some this means investing in entire new production lines, but for others, close cooperation between IPCO and OEMs has made it possible to upgrade the conveyor system while retaining existing ovens.
Lower carbon footprint, lower energy costs
Minimising environmental impact is of course central to every responsible business’ plans these days. This can be for reasons of corporate responsibility, genuine environmental concern, or simply the reality of rising energy costs (most likely a combination of all three). Whatever the driver, it’s clear that the bakery industry is moving down a path towards greater energy efficiency and reduced carbon emissions.
While advances in oven technology are likely to deliver the greatest savings in this area, every aspect of the production process needs to be evaluated, from upstream mixing to downstream packaging. And this includes the conveyor belt.
Every time the belt exits the baking chamber, it begins to cool and has to be heated up again. As a result as much of 25% of an oven’s energy consumption is used in heating the belt.
Solid steel belts are lighter than wire mesh so require up to 30% less energy to heat. That’s 30% less carbon and 30% lower fuel bills. And perforated steel belts are lighter still. This weight advantage also means less energy is needed to ‘drive’ the belt through the oven, further driving down energy costs and carbon emissions. And these savings are continuous.
Recent research in the UK suggests that the overall energy bill of the average bakery is almost exactly $1m, and that oven heating accounts for around 44% of this, so the sums are not insignificant.
And there are other environmental benefits of a steel belt…
Minimising the risk of acrylamide build-up
However clean and well managed a bakery operation might be, a gradual build up of carbon residues on the bake oven belt is virtually unavoidable and this can be detrimental to both the taste and the appearance of a baked product.
As well as impacting on quality, the negative effect of acrylamide on human health has now made it a health issue too. And since the introduction of Regulation EU 2017/1258, it is a legal responsibility to reduce levels of this potentially carcinogenic by-product of the baking process.
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. As a result, steel belts are inherently quicker and easier to clean than mesh belts.
As well as the obvious advantage of minimising the risk of harmful acrylamide build-up, this inherent ‘cleanability’ also means less water consumption, reduced use of chemicals/detergents, and – depending on the cleaning method – less energy expended on heat.
Quick and effective cleaning also has the advantage of rapid changeover from one product to another, enhancing the overall productivity and efficiency of a bakery.
This unique combination of qualities doesn’t just come from the inherent qualities of steel of course; every belt is meticulously engineered to perform as it should.
“The baking process requires not only specific thermal properties but also mechanical ones: the belt needs to provide stable working conditions when tensioned,” added Karlsson. “During the production process, the necessary mechanical properties are created in order to engineer long-lasting flatness and straightness into the belt. These qualities are essential for an efficient continuous baking process.
“The belt must be able to transfer the heat from the heating media to the product in an even way. This means the colour of the belt surface is important. A consistent, dark belt colour will maximise heat transfer and ensure an even bake. Specific heat treatments are therefore applied during the production process.”
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Supporting OEMs with design and high quality conveyor components
While most of IPCO’s work with the bakery industry is focused on the manufacture and supply of steel belts to oven builders and end users, the company can also work in partnership with OEMs, supporting them in system design and supplying a full range of ancillary conveyor equipment from sheaves and shafts to bearings and breakpoints.
This system expertise has resulted in the development of a range of solutions that can maximise oven efficiency and performance. These are just two of them:
Graphite skid bars
Solid steel bake oven belts require a regular and carefully controlled deposit of graphite on the inside of the belt to ensure optimum performance and maximum durability. IPCO’s graphite stations automatically apply graphite as the belt travels through the oven. As well as decreasing friction, this also prevents rust. Other benefits include:
Eliminates need for lubrication before start-up or during operation
Eliminates slip-stick problems and reduces vibration
Reduces deformation problems
Simplifies removal of spillage on return strand
IPCO supplies two types of skid bar; soft graphite for general bake oven belts and a harder option for higher temperatures and/or perforated steel belts.
Compact belt tracking
IPCO offers a full range of active and passive belt alignment controls for accurate and effective belt tracking, including belt edge detectors, guide rollers and compact/automatic tracking devices.
The Compact Belt Tracker (CBT), available in a range of sizes to suit belt widths from 600-3000mm, is light, self-supporting, and can be installed on any conveyor. The device manages tracking by tilting the belt using a linear actuator. Control options include simple logical control and sophisticated PID control.