Mixers are built to last. When cared for properly, these sturdy pieces of equipment can keep working for 20 years. But that’s the trick — caring for them properly. If not, mixers won’t go the distance.
Today’s mixers are robust enough to withstand the torque inside the bowl and the pressure washing and chemicals that come with today’s food safety needs. And they are a big investment. However, these giants in the bakery — whether horizontal, vertical or continuous — can develop dough and aerate batter for a long time when bakers treat them right.
“Mixers may look similar on the outside, however, how robust or sturdy the construction of the mixer is on the inside will affect how well these components will do at absorbing the energy produced by the mixing action, meaning less vibration, and providing years of reliable service for the baker,” said Terry Bartsch, executive product manager, dough systems at AMF Bakery Systems.
Today’s design and technology makes it easier than ever to right-size the mixer, get an efficient mix and automate preventative maintenance.
The first trick to getting the most out of a mixer is to choose the right one. Various doughs and batters will demand different requirements from a mixer, and this goes beyond going horizontal, vertical or continuous.
Bakers need to know the stiffness of the dough or viscosity of the batters to choose the proper motor size.
“The most certain way to size the motor appropriately is to collect amp data on the existing mixer that is being used to mix the product,” said Andrew McGhie, director of sales, Shaffer, a Bundy Baking solution. “The amp data will show the peak loads on the motor as it mixes the product. This will show how much horsepower is being used by the existing mixer to mix a certain batch size.”
Bakers and equipment suppliers can use this information to extrapolate to larger batch sizes to determine the required size of the motor and the resulting torque for a new mixer.
“This is key because the larger the motor, the more torque is generated, which means the mixer needs to be built to withstand the higher torque levels,” Mr. McGhie explained.
Much of this decision will be dependent on the type of dough being mixed.
“You will want to look at absorption level of the final dough, stiffness of the dough, range of the dough being mixed,” Mr. Bartsch explained. “Another key factor is the speed of the agitator. With this information, you should be able to select the proper size motor for the job. I always say, you only get one opportunity to get the horsepower right, and that is during the design stage.”
For batter mixers, Kevin Wilkinson, North American sales, Tonelli Group, recommended bakers provide original equipment manufacturers (OEMs) with the complete specifications of the product, including pounds per hour to be produced, batch size, product density, specific gravity and centipoise. It’s also critical that bakers use the mixer within recommended production rates.
“We engineer the equipment for extreme duty, but we recommend that the customer use the equipment as designed by the manufacturer,” he said.
When bakers push their mixers to operate at max capacity continuously, it shortens the equipment’s lifespan.
“The big thing people tend to do is overloading the mixer or not staging it correctly or making too viscous a batter and exceeding the limits of the machine,” said Bob Peck, vice president of engineering, E.T. Oakes.
Damian Morabito, president, Topos Mondial Corp., pointed out that upsizing the motor can give bakers some breathing room when it comes to overloading the mixer.
“We know bakers will add too much scrap dough back in the mixer or an operator will double draw on flour and single draw on water, and they will try to mix through it,” he said. “At that point, you’re mixing clay, not dough.”
Capacity charts can help determine which mixer size a baker should choose. These allow OEMs and bakers to see what volume a mixer can handle by type of dough and related dough density.
“The strength of the mixing bowl is another key feature of the mixer,” Mr. McGhie said. “What is the design of the bowl? Does it have the stronger vertical design, or is it a more traditional horizontal channel jacket design?”
OEMs are designing mixers to be more robust and durable to withstand the forces the agitator and dough create. AMF Bakery Systems’ DuraBowl design reinforces the mixer balance and stability to lengthen the life of the mixer bowl. It also eliminates cooling leakage and maintains the specified dough temperature.
It’s not all size and strength, however, according to Peter Frederiksen, sales director, Varimixer.
“The size of the motor in itself does not ensure a strong mixer,” he said. “The construction of the power transfer and the speed range also has a big impact on the performance and capacity of the mixer.”
Reading Bakery Systems (RBS) designs its Exact Continuous Mixers for the type of dough being mixed and uses advanced variable frequency drives to monitor kilowatt (kw) draw and instantaneous spikes in amperage.
“Should either of these things occur, the mixer will automatically shut down,” said Matt Risser, Exact Mixing product line manager, RBS.
Mixers can also be designed without components that require much maintenance. On its large mixers, Topos Mondial removed the gearboxes that require oil changes and replaced them with direct belt drives.
AMF Bakery Systems’ Open Frame Mixer operates with a direct-drive tilt system, which eliminates the need for hydraulic chains or belt tilt components. This creates a maintenance-free tilting operation.
The design of Rapidojet’s mixing chamber keeps maintenance tasks to a minimum. Since dries and liquids never meet until the patented mixing chamber, sanitation and maintenance are simplified and extremely low cost. The small mixing chamber replaces all traditional mixing bowls and is cleaned in a sink in just a few minutes.
This article is an excerpt from the October 2021 issue of Baking & Snack. To read the entire feature on Mixers, click here.