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Technology Transfer

INDIRECT RADIANT OVENS

Baker Pacific are the designers and builders of international quality Direct Gas Fired and Indirect Radiant ovens. Our experience in design, manufacture, installation and commissioning is over 30 years originally with Baker Perkins Ltd.

Baker Pacific combination oven Direct Gas Fired / Indirect Radiant Oven
  • Indirect Radiant ovens bake with infrared radiation, providing a stable, penetrative heat transfer, baking the product from inside and creating excellent volume, structure and texture.
  • Suitable for all types of products except high rate crackers. Particularly suitable for all short dough biscuits, cookies and semi-sweet biscuits
  • Combination Direct Gas Fired / Indirect Radiant ovens are the optimum specification for most biscuit and cracker baking
  • Indirect Radiant ovens are suitable for our Heat Recovery System giving the best fuel efficiency as shown by independent test.

HEAT RECOVERY SYSTEM

The Indirect Radiant oven has a single burner in each zone. The burner heats a circulation system providing radiant heat to the products. The products of combustion do not enter the baking chamber. As the burners draw in combustion air, the excess flue gas is exhausted through a natural convection flue in each zone. This hot flue gas is partially collected and used to heat one or two additional oven zones, which do not have burners.

Baker Pacific Heat Recovery Zone

The Heat Recovery system will typically improve fuel efficiency by 15% as shown by independent tests.

Product Oven type Oven size kWh/kg of biscuits
Rotary moulded Indirect Radiant + Heat Recovery System 1.2m x 100m 0.404
Rotary moulded DGF/convection 1.2m x 60m 0.430
Rotary moulded DGF/convection 1.5m x 100m 0.441
Rotary moulded Indirect Radiant 1.2m x 100m 0.475
Rotary moulded DGF/cyclotherm 1.2m x 60m 0.492
Snack cracker DGF/convection 1.2m x 90m 0.477

SCOPE OF TECHNOLOGY TRANSFER

  • Oven design data
  • Assembly and detail manufacturing drawings
  • Parts lists
  • Material specifications
  • Key component specifications
  • Control and safety systems
  • Electrical wiring diagrams
  • Installation schedule
  • Operation and maintenance manual
Complete manufacturing drawings and parts lists

For more information, please contact bakerman@bakerpacific.com

Direct Gas Fired Ovens

 

Baked potato snacks

Production process

“Baked not fried” has become an established healthy, low fat choice for consumers in many markets. Potato snacks and crackers are baked with infrared radiation on Direct Gas Fired ovens or hybrid DGF/Indirect Radiant ovens.

DGF-IR oven

Baker Pacific Direct Gas Fired / Indirect Radiant oven

The production process for potato snacks follows that for crackers and wheat based snacks quite closely. With some modification, cracker lines can produce baked potato snacks in addition to potato crackers.

Potato crackers from Khong Guan, Indonesia                           Potato snacks from Walkers, UK

The ingredients for baked potato snacks may be mixed on continuous mixers or on horizontal high speed mixers with suitable modifications or on plough share type mixers with bottom discharge. All the dry ingredients are blended, fat is added and finally water is added. Horizontal high speed mixers require a steam jacket and suitable modifications to the bearings and seals. The dough is heated during mixing to gelatinise the starches.

HS mixer

 

 

 

 

 

 

 

 

 

APV Baker High Speed Mixer

The dough is sheeted and gauged to produce a dough sheet of approximately 0.75mm thickness. Potato doughs are tough and require heavy duty forming equipment. The robustness and accuracy of the gauging equipment is critical as variations in thickness of the snacks will cause variations in colour after baking. Achieving the minimum variation in thickness requires large diameter gauge rolls, 400mm diameter and these may be of solid construction to minimise deflection.

gauge rolls

 

 

 

 

 

 

 

 

Heavy duty gauge rolls from Baker Perkins

 

Ripple snacks are formed on a final gauge roll unit, which has grooved rolls, which intermesh to form the ripple in the dough sheet. By using one plain and one grooved roll, other forms such as hollow flutes can be made. These rolls only form the dough sheet and do not alter the thickness. When making plain products the ripple roll gap is opened to allow the product to pass through without ripples.

Pic 5

 

After gauging, the snacks are cut by a rotary cutter. The scrap dough is lifted and may be milled before returning to the mixer. Cracker doughs which have a strong, extensible dough sheet may be returned to the sheeter.

Triangle snacks

 

Potato snacks are baked on pre-heated Z47 type wire mesh or heavy mesh oven bands, such as Ashworth CB5. The ovens require high radiant heat and may be either a Direct Gas Fired (DGF) oven or hybrid DGF / Indirect Radiant oven. Convection ovens are unsuitable as the convective air will disturb the very light snacks on the band and will cause snacks to be blown off the band. Baking times are of the order of 4 minutes and the output of a 1.0m x 40m oven will typically be around 500kgs / hour.

About - ovens

Baker Pacific Radiant oven baking by infrared radiation

The snacks are conveyed directly to the oil spray and flavour applicator. The flavours may be added to the oil and the slurry pumped through the oil spray. This method has the disadvantage of possible blockages and increased cleaning time, particularly where more than one flavour is applied on the same line. The alternative is to use a flavour applicator after the oil spray machine. The flavour is metered on to the snacks while they are agitated in a rotating drum. After flavouring the snacks are cooled and conveyed to packaging.

Storeveyor

 

 

Storeveyor for potato chips from Gough Engineering

Packaging is usually a vertical Form fill seal pack, but may also be a block bottomed bag or a bag in a box.

Crinklys - Walkers packs

Crinklys potato snacks from Jacobs and Walkers Baked from UK

 

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