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Grain & Feed Milling Technology is published six times a year by Perendale Publishers Ltd of the United Kingdom.All data is published in good faith, based on information received, and while every care is taken to prevent inaccuracies, the publishers accept no liability for any errors or omissions or for the consequences of action taken on the basis of information published. ©Copyright 2010 Perendale Publishers Ltd. All rights reserved. No part of this publication may be reproduced in any form or by any means without prior permission of the copyright owner. Printed by Perendale Publishers Ltd. ISSN: 1466-3872

Digital Re-print - September | October 2011 Producing Flaked Breakfast Cereals

www.gfmt.co.uk

Producing flaked breakfast cereals from pellets or grits by passing them between contra-rotating rollers is a

prime example of a process that is much more complex than it appears. Achieving the consistent high quality demanded by consumers at the high outputs needed by producers requires a great deal more process expertise and precision engineer-ing than might be assumed.

Baker Perkins flaking rolls are used by lead-ing multinational and regional breakfast cereal

makers, to convert cooked grains and extrud- ed

pellets into a wide range of corn, bran, mul-tigrain and other flakes ready for toasting. Grits and pellets up to 10mm thick are reduced to flakes as thin as 0.3mm.

With 30 years experience in providing flaking rolls to customers throughout the world, Baker Perkins cite the control of three key process variables as essential to achieving the highest flake quality.

The first is achieving an even, regulated product feed across the full width of the rolls. Uneven feeding causes differential heat build up in the rolls and leads to inconsist-ency in flake thickness. Colour, moisture, size and texture of the finished product are all adversely affected. To avoid compromising

quality with excessive ‘dou-bles’ it is important that the feed be regulated to ensure that pellets and grits are processed individually

To achieve these objectives for dif-ferent product types Baker Perkins engineers product-specific feed systems. Extruded pellets and multigrains are fed by a vibra-tory conveyor and spreader. For cooked corn grits, a grooved roll feeder is used, with the flexibility to adjust gap height and roll speed. A

distribution box is typically used for whole grain wheat.

The second challenge is to maintain a precise and constant gap between the 2-ton contra-rotating flaking rolls: this is crucial to achieving consistent product quality. Any minor variation changes flake thickness and bulk density, resulting in under- or over-toasting and rejected prod-uct. Adjustability is also important to maximise flexibility.

A recently upgraded automated hydraulic system positions each roll via a linear trans-ducer: the roll gap is continuously measured and adjusted against a set point. Effective sealing against dust ensures reliability and a low cost of ownership. The system is com-pact and accommodated within the enve-lope of the machine to minimise footprint, but is readily accessible for maintenance.

The third process variable that must be accurately controlled is roll surface tempera-ture. Consistent roll surface temperature is essential for optimum flake consistency and is achieved via an effective water cooling system.

The latest generation of machine incorporates an advanced roll cool-ing and water circulation procedure. Effectiveness has been refined through a contraflow water circulation system, with water channels close to the surface to maximise heat removal efficiency. High flow rates of up to 10,000 litres per hour control water temperature within a 0.2ºC tolerance band – water temperature can be varied by the operator.

The solid flaking rolls themselves offer the unique feature of a welded outer

PRODUCING FLAKED bREAKFAST CEREALS

Grain&feed millinG technoloGy22 | September - october 2011

ing multinational and regional breakfast cereal makers, to convert cooked grains

and extrud- ed

build up in the rolls and leads to inconsist-ency in flake thickness. Colour, moisture, size and texture of the finished product are all adversely affected. To avoid compromising

quality with excessive ‘dou-bles’ it is important that the feed be regulated to ensure that pellets and grits are processed individually

To achieve these objectives for dif-ferent product types Baker Perkins engineers product-specific feed systems. Extruded pellets and multigrains are fed by a vibra-tory conveyor and spreader. For cooked corn grits, a grooved roll feeder is used, with the flexibility to adjust gap height and roll speed. A

22 | September - october 2011

FEATURE

GFMT11.05.indd 22 04/10/2011 15:15

layer of hardened tool steel over a tough carbon steel interior. As well as long life – typically 10,000 hours before re-grinding – there are additional cost ben-efits. The outer layer permits a number of re-grinds, and at the end of natural life another outer layer can be welded to the roll: conventional rolls need replacing at this point. The outer layer can also be repaired in the event of damage by stones or other foreign objects.

The scraper blades that clean each roll are made of hardened but flexible alloy to ensure uniform contact across the roll width. Two features extend blade life: they are held in position by a variable pneumatic pressure system; the blades are also reversible and may be reground several times. An optional oscillating knife increases the effectiveness of scraper action.

A major improvement introduced on the latest generation of machines is the substitution of a precision timing belt drive for the previous torque arm gearbox. With independent drive to each roll, speed can be varied to change the nature of the flake if required. Maintenance is reduced because AC motors and timing belts require no routine work.

In an environment in which workplace noise is rapidly growing as an issue, the new flaking roll drive features acoustic covers over the roll drives as standard; there is also an option for hinged acoustic covers at each end of the unit.

These flaking rolls are designed for ease of use. There is full PLC control with a touch-screen HMI providing clear process visualisation and intuitive operation. The set-up facility is recipe driven, and there are comprehensive alarm functions plus a recent alarm history.

Simple, open design maximises accessibil-ity to the flaking rolls themselves for clean-ing and maintenance whilst conforming to worldwide safety standards; the simple frame construction allows for easy roll removal. The latest machine also has a smaller foot-print.

On leaving the flaking roll, the product is transferred to a toaster where a mois-

ture content of 18 to 20 percent must be reduced to 3 percent. Discharge options to suit customer preference include a bi-directional belt conveyor, a vibratory con-veyor, and a vacuum take-off system with sampling tray.

The choice of standard 780 or 1220mm roll widths allows a range of outputs to a maximum of 1,500kg/hour.

Flaking rolls are an essential module in the Baker Perkins Cereal Master TX and EX expandable lines. These allow manu-facturers to install a basic line for a limited range of cereals, and then add more units to increase the range and value of products as market and business conditions change.

The Cereal Master TX includes a flaking roll in its standard configuration for making wheat and bran flakes using the tra-ditional steam cooking proc-ess. Other units can be added later to extend the prod-uct range to include corn, multigrain and frosted flakes.

A stand-ard Cereal Master EX line produc-ing extruded cereals such as corn balls, multigrain

rings, alphabet shapes, and cocoa balls can be extended, through additional units (including the flaking roll), to make a range of flakes, multigrain flakes and filled pillows.

Baker Perkins provides the process and engineering expertise to reconfigure the lines, and works with customers to develop new product ideas, often in the Baker Perkins Innovation Centre at Peterborough, where a comprehensive range of equipment is available for trials. Each installation is individu-ally specified to match the customer’s exact product needs.

Our technology based on the 2-Parameter-Resonance-Technology, this makes it possible to control density and moisture in your products fast accurate cost effective

Inline moisture + density

www.doescher.com

AD_DoescherDoescher_90x132.indd 1 30/09/2011 11:08

Grain&feed millinG technoloGy September - october 2011 | 23

FEATURE

GFMT11.05.indd 23 04/10/2011 15:15

Innovations for a better world.

Built by feed millers for feed millers. Equipped with the industry‘s most efficient

drive system, the new Bühler pellet mill Kubex™ T saves up to 20% of energy –

while boosting line capacity to up to 80 tons per hour. With the Kubex™ T

you save costs, reduce your carbon footprint and make your operation even

more productive. Gaining competitive advantages has never been easier.

For more information please visit www.buhlergroup.com/kubex-t

Bühler AG, Feed & Biomass, CH-9240 Uzwil, Switzerland, T +41 71 955 11 11, F +41 71 955 28 96

fu.buz@buhlergroup.com, www.buhlergroup.com

Kubex™ T pellet mill.

Developed in close cooperation

with leading feed millers.

Direct drive concept. Saves up to

20% of energy compared to

conventional drive systems.

Variable die speed. Formulation-

specific optimization of production

process and pellet quality.

Up to 585 kW motor power. Boosts

line capacity to up to 80 t/h.

Belt- and gearless drive system.

For minimum maintenance and

ultimate machine availability.

ABS control for press rolls.

Prevents roll slippage and protects

machine against blockages.

360° accessibility. Wide-opening

sliding doors on both sides.

The world’s most compact design.

Fits anywhere and everywhere.

Almost double capacity with same

footprint as conventional pellet mills.

DPEF_210x297_engl.indd 1 28.07.2011 12:10:13GFMT11.05.indd 50 04/10/2011 15:17 GFMT11.05.indd 49 04/10/2011 15:17

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A subscription magazine for the global flour & feed milling industries - first published in 1891

In this issue:

• Sample preparation of feeds and forage for NIR analysis

• 15-Year Celebration: Fortifying with folic acid prevents 22,000 birth defects annually

• Global Feed Markets:Wheat supply grows and grows as corn crop shrinks

October 2011

• Producing Flaked breakfast Cereals

• Direct Cold Plasma: The innovative answer to odour control in the food and feed industry

• Milling Technology Redefined

GFMT11.05.indd 1 04/10/2011 15:14

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