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Hot air for quick cooking

The borders between retail and gastronomy are increas­ingly blurry. Gas stations, super­mar­kets, and even clothing stores are offering their customers warm snacks. But space on the counter and hungry customers’ time are both in short supply. Compact high-speed ovens solve the problem, with the help of EC blowers from ebm-papst.

The world eats out. More and more people are not cooking at home, but rather eating on the go and prefer­ably at all times of day. When filling up the car, shop­ping or at a bar after work. The classic restau­rant is no longer the first desti­na­tion, for things have to move fast – and taste great never­the­less.

The food industry has reacted: a broad spec­trum of frozen prod­ucts makes it possible for stores to offer an exten­sive menu even without a chef. The trend is clearly toward front (“on-stage”) cooking: customers want to see how their food is prepared. This presumes that an appro­priate and easy-to-operate device with a pre-programmed baking program is avail­able, because pizza is supposed to be nice and crispy.

The conse­quence: on the shop counter, where there isn’t much space, kitchen appli­ances have to be as compact as possible and work as quickly as possible, for prepa­ra­tion shouldn’t take more than a minute or two. The next customer doesn’t want to stand in line for long. There­fore, what’s needed is a lot of power in a small space. Compact high-perfor­mance ovens are just the thing here.

Exper­tise from baking lines

Fig. 1: Effi­cient combi­na­tion: compact hot-air-impinge­ment ovens unite convec­tion, radi­a­tion, and microwave tech­nology. This keeps prepa­ra­tion times as short as possible.

Manu­fac­turers rely on so-called hot-air-impinge­ment ovens, which combine convec­tion, radi­a­tion, and microwave tech­nology. Hot air is blown through nozzles onto the baked goods at high pres­sure of up to 4,000 Pascal (Figure 1). Temper­a­tures of up to 450 degrees are thus possible and the pizza is nice and crispy in no time at all. Dishes can be prepared up to 15 times faster than with tradi­tional ovens.

The tech­nology is not new. In the food processing sector, it has long since been tested on long baking lines – however, there the space for the blowers that move the hot air plays a subor­di­nate role. The situ­a­tion is different for high-perfor­mance ovens for front cooking: so that they fit on the shop counter, the space for the tech­nical compo­nents is quite limited. Here, AC tech­nology cannot achieve a power density compa­rable to the EC fan.

But in the food processing sector, EC tech­nology offers poten­tial for process opti­miza­tion thanks not only to its enor­mous power poten­tial with greater energy effi­ciency, but also with respect to its possi­bil­i­ties for networking.

Great perfor­mance in a compact package

Blowers with EC tech­nology have the advan­tage that they require little space yet never­the­less provide great power. Their compact size is possible because the elec­tronics are arranged flex­ibly around the EC motor and also because the motor requires no vari­able frequency drive (Figure 2). There­fore, blowers with EC tech­nology are predes­tined for compact high-perfor­mance ovens (Figure 3).

Fig. 2: Lots of power in a small space: Thanks to EC tech­nology, the VBS 170 requires only a little space. That's why it's well-suited for compact high-perfor­mance ovens.

Fig. 3: The ebm-papst blower is constructed so that it can be adjusted flex­ibly to the instal­la­tion posi­tion in the manufacturer’s device. Thanks to its high power density and compact design, highly-effi­cient kitchen appli­ances can be created.

The VBS 170 centrifugal blower (formerly the R170) with EC motor from ebm-papst was adapted espe­cially for use in such appli­ca­tions. Its speed of more than 3000 rpm and its back­ward-curved blades ensure great aero­dy­namic effi­ciency with low energy consump­tion. This makes high pres­sures with high air flow possible.

The advan­tages are best displayed when the design of the EC blower is attuned to the flow design. That’s why, on request, ebm-papst engi­neers work closely with manu­fac­turers, even during the design phase. Since ball bear­ings are used for the blowers, there various ways to install them. A sleeve bearing wouldn’t work since it can’t always accom­mo­date forces in an axial direc­tion. Heavy, hanging or hori­zontal impellers would quickly wear down the bearing.

Another advan­tage of EC blowers is their dynamics: they accel­erate very quickly to the desired nominal speed. No valu­able seconds are lost when they are heating up. 16 hours of contin­uous oper­a­tion is not a rarity with these compact high-perfor­mance ovens. For a high level of avail­ability and corre­spond­ingly high sales of ready-to-eat foods, robust tech­nology is indis­pens­able. Here too, EC tech­nology scores points with its long service life and low wear.

All advan­tages at a glance

The VBS 170 blower solu­tion from ebm-papst is opti­mally attuned for use in high-speed ovens:

  • The EC tech­nology unites a lot of power with a small space, which makes compact devices possible.
  • The centrifugal fan impeller is made of stain­less steel, so it fulfills the hygiene require­ments of gastronomy.
  • The motor is vibra­tion-damped on a special mounting plate and fastened so that it is ther­mally decou­pled.
  • The noise emis­sions are low thanks to the design of the blower.
  • Long service life even with constant use due to robust EC tech­nology.
  • EC systems can be networked easily, entirely in the service of Green­In­tel­li­gence.
Tech­nical data

The most impor­tant facts and figures about the VBS 170 blower solu­tion:

  • Maximum power consump­tion: 300 W
  • Nominal voltage: 230 V AC 50/60 (addi­tional voltage ranges on request)

Heat-resis­tant, quiet, and hygienic

Due to their compact designs, the blower and heat source are close together in these ovens. However, the high temper­a­tures cannot harm the tech­nology: ebm-papst engi­neers have relied here on their many years’ expe­ri­ence in the heating tech­nology sector and decou­pled the fan and motor (Figure 4). These are on two levels that are sepa­rated by thermal decou­pling elements. If neces­sary, an addi­tional cooling impeller reduces the thermal load on the motor’s electro­mechan­ical compo­nents.

Fig. 4: The fan and motor unit are decou­pled from one another. This means the blower is well-suited for use in the high-temper­a­ture range. The decou­pling elements also reduce noise emis­sions that contribute to struc­ture-borne sound.

This design prin­ciple also results in lower noise emis­sions. Because the ovens are frequently in the sales area, volume is a deci­sive factor. Customers shouldn’t be disturbed by noise. Thanks to the decou­pling, the mounting plates are spring-mounted, there are few vibra­tions, and struc­ture-borne sound is corre­spond­ingly low. In addi­tion contributing to the aero-acoustics, this means that noise is kept under control.

The fan’s wheel is made of stain­less steel, which does not rust in the humid-hot work envi­ron­ment. ebm-papst blowers there­fore fulfill another impor­tant prereq­ui­site in the gastronomy sector: compli­ance with hygiene regu­la­tions.

Ready for the future

Digi­tal­iza­tion has long since arrived in the profes­sional kitchen sector: many devices are already Internet-capable and there­fore networked. Precisely for larger fran­chise compa­nies, this is a big advan­tage, since they can program new cooking programs centrally onto hundreds of high-speed ovens and delete old programs.

But that is not the only benefit of connec­tivity! ebm-papst’s EC tech­nology can also be incor­po­rated easily into existing commu­ni­ca­tion struc­tures, entirely in the service of Green­In­tel­li­gence. An impor­tant prereq­ui­site if in the future topics such as the recording and eval­u­a­tion of oper­ating states in general or predic­tive main­te­nance are supposed to become reality.

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