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A TRIZ-based Creativity Tool for Food Processing Equipment Design
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A TRIZ-based Creativity Tool for Food Processing
Equipment
Design
M. Totobesola-Barbier, C. Marouz�, F. Giroux
CIRAD-AMIS-PAA1, Equipment and Process Design Laboratory
73, avenue J.-F. Breton
34398 Montpellier CEDEX 5, France
Tel: 33 (0)4 67 61 65 97
Fax: 33 (0)4 67 61 44 15
francois.giroux@cirad.fr
Abstract
This article presents the customizing of TRIZ concepts for
the development of a methodology to systematically improve creativity for the
search for appropriate engineering principles for food equipment in the context
of developing countries. Such methodology is necessary to help generate
equipment that are adapted to the socio-economic and technical environment, as
often demanded in these countries. The bases of this specific methodology are
the TRIZ ideas of using predefined standard or general problems and solutions
coupled with the creation and utilization of a structured capitalization of
knowledge. They facilitate and lead the search towards a wider panel of
potential solutions by nurturing creativity and favoring the transfer,
modifications and/or combination of pertinent existing solutions (engineering
principles). This tool meets the methodological needs of designers working in a
context characterized by scarce investment, lack of knowledge, insufficient
scientific information and referential. In this methodology, the standard
problem is based on the main function of the equipment to be designed and the
specification of the products to be processed. A previous inventory, analysis
and classification of existing unit operations in the food industries permitted
the predetermination of the categories of main functions and the potential
associated principles involved in agro-food processing. The identification of
the corresponding standard solutions is facilitated by the use of the same data
(function/product specification) in a database purposely created on these
principle. This database is a structured referential that orientates and
facilitates the search. It also contains additional information on existing
applications of the principles. Two examples of application of this methodology
are given. This method has been developed in a particular context but it can be
used also by SMEs in industrial countries, in order to re-organize TRIZ
databases in relation with specific industrial sector.
Key words: creativity, design, developing countries,
equipment, food processing, function, TRIZ, unit operations
Introduction
In many developing countries there is an increasing demand
for small and medium-scale agro-food equipment for post harvest handling and
processing. The necessity to guarantee a good quality and conservation for trade
is the main reason to this demand. The offer has been often limited to imported,
copied, and adapted equipment designed mainly in developed countries. This offer
has been inadequate to the socio-economic and technological context because of
its high investment, operating and maintenance costs, high technological level,
inappropriate scales and/or its technological features that are not appropriate
to products specific to tropical and sub-tropical countries (Odey� Finzi, Berot
Inard et al., 1996). To better respond to this need, universities, research
centers and development organizations have made efforts at promoting local
innovation, but they were insufficient. Small teams of designers were set up to
work on design projects, but most members had a background only in mechanics
while they should also possess skills in finance, management, agronomy,
agro-food process engineering, marketing, and sociology. Consequently, they
tended to rapidly generate prototypes based on the engineering principles that
they know of (Ndiaye, Marouz� et al., 2001). These prototypes often failed
because of insufficient consideration of the other factors that need to be taken
into account in design process, and lack of knowledge of the specificity of
agro-food products (i.e. biochemical and biological properties, high sensitivity
to changes in physical and chemical parameters such as temperature, pH). In
addition, the scarcity of investment, the lack of communication in scientific
and industrial information, and the absence of appropriate design method have
also affected these efforts.
In order to support the local design of agro-food equipment,
CIRAD and its partners have developed and validated during the last five years,
a specific methodology called CESAM2 (Giroux and Marouz�, 1997). The development
of the CESAM methodology was based on the study of the traditional design
process of equipment in developing countries. This study has allowed the
definition of the weaknesses of the traditional approach, the identification of
the improvements needed, and that of compulsory stopping-off points for the
design trajectory to be successful. The CESAM methodology is based on a
multidisciplinary approach and a �concurrent engineering�-type organization of
its different phases. It helps in the definition of the objectives, the tools,
and the required resources of design projects (Marouz�, 1999). The eight
concurrent phases of CESAM are:
-
Launching of the design project (identification of
general objectives, users, team, leader, budget, schedule�)
-
Analysis of users� needs and state-of-the-art (functional
expression of needs, list of relevant existing equipment, state of
competition, cost objectives, risk evaluation�)
-
Searching of engineering principles for the equipment to
be designed (use of creativity, functional analysis, knowledge
capitalization)
-
Selection of technical solutions based on predetermined
socio-economic, technical and environmental criteria
-
Equipment definition (definition of parts, assembly�)
-
Manufacture of prototype
-
Prototype validation
-
Equipment distribution (popularization) and project
evaluation
Whereas phase 3 (searching of principles) is one of the most
important phases, its implementation presented difficulties during the
validation of the CESAM methodology by design projects in different countries (Ndiaye,
Marouz� et al., 2001). It is indeed a key phase of the design process since it
is the transition phase between the statement of the problem and the finding of
a solution (Cavalucci and No�l, 2001) -the problems tackled in this article is
of the type: �What is the most appropriate engineering principle for an
equipment to be designed for a given purpose?�. The phase 3 of CESAM is
where ideas of solutions, i.e. potential principles, should sparkle from design
teams. Therefore it depends on their creativity. Since creativity is nurtured by
knowledge (Ngassa, Bary et al., 2002), the understanding of the basic scientific
principles involved in food processing -chemistry, biology, and engineering-
helps the generation of new processes and modify existing ones (Earle, 1983).
The fact is, design teams� lack of basic knowledge makes difficult the
identification and generation of potential principles; hence the need for a
design methodology that takes into account these limitations.
This article describes our contribution to facilitate the
stage of principle search of the design of agro-food equipment in the context of
developing countries. It consists of the development of a TRIZ-based creativity
tool focused on engineering principles utilized in food technology. This tool is
meant mostly to facilitate the identification and transfer of potential
principles from the processing of a product (existing ) to that of another
product (versus a transfer from an industrial sector to another as favored in
classical TRIZ). The TRIZ approach have been chosen because unlike most
creativity tools based on the psychology of the users (e.g. brainstorming,
synectics, etc.), TRIZ techniques present the advantage of guiding and
facilitating the search for potential solutions (Zusman and Zlotin, 1997).
Considering the constraints mentioned and the type of problems to be treated,
TRIZ knowledge-based tools such as predefined standard patterns of problems,
standard solutions, and scientific effects database (Altshuller, 1984) have been
selected and adapted because they are more useful. Besides, the TRIZ method is
appropriate to the solving of complex problem. Consequently, it is also helpful
in overcoming a complexity that is rather caused by the many limitations than a
high technological level (In developing countries, equipment design mostly
concerns intermediate level technology.).
This article presents the development and the functioning of
a TRIZ-based creativity tool for the search of engineering principles in
agro-food equipment design. It includes the following parts:
-
The formulation of �standard problems3� based on the
definition of the principal function of the equipment to be designed and the
characterization of the products to be processed to facilitate the
identification of all potential solutions (in this case, the potential
principles)
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The definition of �standard solutions� to lead the search
toward pertinent principles that can be directly applied, or modified or
combined to generate new ones
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The setting up of a database on scientific principles
applied in agro-food processing, and existing applications to be used as a
reference
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The functioning of the methodology for the search of
principles in agro-food equipment design
For the development of these components, a collection of
relevant information was necessary. For this purpose we undertook an inventory
of existing unit operations4 in food industries, followed by their functional
classification and the statement of the principles involved, as defined in Food
Engineering Science (Earle, 1983).
1. Definition of standard problems based on process function and product
characterization
For the development of a methodology for principle search, we
adapted the first phase of the general TRIZ model (figure 1). This phase
consists of analyzing and reformulating specific problems into standard or
general problems by replacing all specific terms with generic ones. The use of
standard problems facilitates the identification potential solutions by two ways
(Salamatov, 1999):
-
It helps identify a wider range of potential solutions that
exist in different scientific fields or industrial sectors, therefore favoring
intra- and interdisciplinary transfer of solutions.
-
It guides the search towards potential specific technical
solutions through to the use of predefined standard solutions.

Figure 1: TRIZ general model (Domb, 2001)
Instead of the TRIZ standards (Substance-field models,
contradicting technical parameters, and physical contradictions), we propose
standard problems that are based on the combination of the main function of the
equipment to be designed and a characterization of the raw material to be
processed as shown by arrow 1 of figure 2.

Figure 2: Standard problems in the methodology for the search
of engineering principles in agro-food equipment design
For example, �How to separate particulate substances of
specified sizes and densities from a liquid of a certain characteristics (e.g.
density and/or viscosity�)� is the standard problem that corresponds to the
specific problems �How to clarify a juice� or �How to stop yeast activity in
brewery�. As will be shown in part 2 of this article, the standard solutions
that correspond to this standard problem can be the principles of separation
based on the difference in nature of the substances to be treated (solid/liquid)
and/or the difference in size (among all particulate solids in suspension and
molecular substances dissolved in the liquid). These standard solutions will
lead to specific technical solutions such as a filtration or centrifugation
techniques. The knowledge of these techniques helps generate new technical
solutions by their modification or combination
1.1 The functional approach
The functional approach used in this new tool for the
definition of the standard problems is the same as in design methodologies such
as the value analysis: the function allows the definition of each task in a
process or one of its activities in terms of goals and not solutions (CSVA,
2002). It is used to specify the purpose or intended use of a product to be
designed (CCE, 1990). Only the principal function is considered. It is defined
as the Main Useful Function (MUF) in TRIZ techniques such as function
mapping and trimming in comparison to other definitions of function5. A system
possesses a MUF and any system component which does not contribute towards the
achievement of this function is ultimately harmful (e.g. in heat exchanger, the
MUF is to transfer heat to the product; everything else in the system is there
solely because we don�t know yet how to achieve the MUF without the support of
ancillary components) (Winkless, Mann et al., 2002). The other main reason for
the use of functionality is because it is a universal concept. It is easier to
understand than the TRIZ standards which require learning, more reflection on
their meaning, and sufficient knowledge for their interpretation into specific
technical solutions (Beaufils, 2000). The advantage of researching and clearly
defining the main and necessary functions is to permit greater scope within the
creative research field. The more �open� the definition, the better it is. An
expression of the functions that suggests solutions reduces this scope (CCE,
1990).
Furthermore, the definition of the function facilitates the
sharing and application of scientific knowledge for the processing of a product
to that of another within the same industrial sector (the case of food
processing industries), and also between widely different industries such as
biology and engineering (Vincent and Mann, 2002). The use of our tool aims
mainly at facilitating the first type of transfer by creating and using in a
logical way a structured referential on existing principles applied in food
processing industries. For instance, the principles of membrane filtration are
used in dairy products processes for the separation of milk components, in
winery and brewery to stop microbial activity by separation of microorganisms.
They are also used in chemical engineering for the production of acids and bases
by using membrane selectivity to separate and combine the right chemical
elements. Examples of interdisciplinary transfer of scientific principles that
recently generated several novel food technologies called minimal processing
methods include pulsed electric fields, high hydrostatic pressure, pulsed
lights or ultrasound, etc. (Fellows, 2000). These new processes that preserve
the flavors, colors and nutrients of the products making them closer to fresh
products.
The inventory and functional classification of about 160 unit
operations mainly used in agro-food processing showed that the functions can be
categorized into five main functions presented in table 1.
Table 1: The main functions of unit operations in food
processing
| Main functionsg6 |
Examples of unit operations |
| 1. Separation |
Sorting, cleaning, grading, sieving or
screening, peeling, centrifugation, filtration, membrane technologies (microfiltration,
ultrafiltration, nanofiltration, reverse osmosis), expression, extraction
using solvents, membrane concentration, dehydration (drying), evaporation,
distillation, concentration, freeze-concentration, freeze drying |
| 2. Mixing |
Solids mixing, liquid mixing (or
emulsification using mixers and emulsifiers), liquid and solid mixing |
| 3. Preservation |
Dehydration (drying), osmotic
dehydration, pasteurization, sterilization, irradiation, blanching,
packaging, controlled and modified atmosphere packaging, freezing, chilling,
freeze-drying, coating, enrobing, fermentation, pulsed electric fields, high
hydrostatic pressure, pulsed light, ultrasound, ohmic heating (direct
electrical heating of foods) |
| 4. Transformation with changes in
composition |
Enzyme technology and fermentation,
cooking, baking, roasting, frying |
| 5. Transformation without changes in
composition |
Size reduction (for fibrous foods:
slicing, flaking, shredding, dicing; for dry foods: milling; for liquid
foods: homogenization), forming (or moulding) |
1.2 Characterization of the products to be processed
The characterization of the products to be processed is also
important in leading the search toward pertinent principles, making it more
effective and rapid. This characterization can be done by using parameters that
are preferably measurable. These parameters can be classified into different
categories to specify the properties of foods as shown in table 2.
Table 2: Categories of properties and measurement parameters for food
products
| Categories of properties
|
Examples of commonly used parameters |
| Geometrical |
Shape, size, length, volume, etc. |
| Physical |
Density, specific gravity, temperature
and pressure of phase changing (e.g. evaporation, freezing, sublimation),
color, water activity7, rate of heat penetration, etc. |
| Chemical |
pH, redox potential8, HLB value9,
miscibility, molecular composition, moisture content, concentration in
components, surface activity, weight average molecular weight distribution,
etc. |
| Rheological |
Viscosity, shear rate, flow rate, slip
velocity, strain amplitude, relaxation time, etc. |
| Biological |
Enzymatic activity, specific growth rate
of microorganisms, etc. |
It is recommended to use a limited number of parameters for
the search to be manageable. In general, the size and the state (fundamental
states such as solid, liquid, gas; and intermediate states such as semi-solids
such as colloid, gel, emulsion, foam, and fluids other than liquids10) are
commonly used. Nevertheless, it is recommended to complement these data with
pertinent parameters such as density, shape, viscosity, pH, phase transition
parameters (temperature, pressure) that specify further the products because a
wide panel of engineering principles are based on them. The characteristics of
the final product may also be specified to give additional hints for the search
of the most appropriate principles. For example, in the case of oil extraction,
the principles of separation to be adopted are different according to the
quality of the targeted final product (e.g. crude vs. refined oil).
2. The standard solutions and the database on principles involved in food
processing
The concept of using standard solutions is used as a link
that leads the search towards pertinent principles which can be directly
applied, or modified or combined to generate new ones. Actually the standard
solutions is based on the same concepts of equipment function and product
characterization as shown on figure 3. The search for the standard solution that
corresponds to the standard problem at hands is facilitated by the use of the
database that has been created to gather in a structured way as much as possible
of the principles applied in agro-food processing. This structure starts with
the same data on equipment function and product characteristics in order to lead
the user to the pertinent existing principles and their applications (figure 3).
3. The database on principles applied in food processing
This database is an integral part of the principle search
methodology. It is a referential that gathers and structures information on
existing agro-food engineering principles. It contains additional information on
existing technical solutions (physical equipment) involving the principles.
Thanks to its content and structure, it increases design teams� knowledge and
creativity, and it guides their search. It helps the identification of pertinent
principles and the generation of new ones by bringing modifications or by
combination (Earle, 1983), it also promotes the generation of suitable technical
solutions (equipment) by thinking by analogy (Domb, 2001),
This database has also been created to provide a more
accessible tool in terms of cost (The TRIZ-based software that include much
larger scientific effects databases are still too expensive considering the
limiting investment capacities of targeted users). It focuses only on agro-food
engineering processes; therefore, it does not favor new transfers of principles
from other scientific and industrial areas. Nevertheless, it can be perfectly
integrated in multidisciplinary effects databases with a structure based on
functions and substance specifications such as that of the software
TechOptimizerTM. This possibility of integration will improve the efficiency of
our tool when these software will become less costly. At present this
integration is only possible for research & development centers, and big
companies provided with such software.

Figure 3: Logical use of the database on food processing for
the search for principles
The main components of this database are:
a) Main functions of equipment in food processing
As developed in part 1.1 of this article, the main functions
define the principal purpose of the equipment to be designed. These main
function, therefore, constitute the first component of the database. They are
complemented by additional information on specific functions. These specific
functions consist of the actions upon specific physical, chemical, geometrical,
or biological parameters to realize the principal function. To preserve food for
example, these actions can be increasing the temperature of the product at a
certain level and maintaining it to for a certain time to ensure the lethality11
on microorganisms, increasing the concentration in preserving agents such as
free radicals compounds (such as in irradiation); decreasing pH or temperature,
etc.
b) Characterization of substances
As shown in part 1.2 this component of the database contains
the second most important information used in this methodology for it permit the
location of the standard solution within the database; therefore it is the
pointer for the identification of pertinent principles.
c) General principles
These are principles that are common to a group of specific
principles. For instance, reduction of water activity include evaporation of
water (a phase transfer) and mass transfer as in salting and in osmotic
dehydration techniques. Each one of these two general principles regroup a
certain number of specific principles. This information is given to indicate
that specific principles can be grouped into general principles.
d) Specific principles
These are specific physical, chemical, geometrical, or
biological principles that can be applied to realize a function. For example,
the specific principles for preservation by reduction of water activity by
evaporation include the following:
-
Energy transfer by contact with heated air or heated
surfaces
-
Energy transfer from light waves (as in sun drying),
-
Energy transfer from ultrasound waves,
-
Difference in pressure as in vacuum dryers (pressure below
atmospheric pressure),
-
a combination principles as in freeze-drying and indirect
solar drying (the food product is in contact with air heated by solar energy)
e) Existing unit operations and equipment
For each function and principles of realization, a list of
existing unit operations and equipment that apply them is given.
f) Operating principle, parameters of control, advantages and
disadvantages of the equipment
All unit operations and equipment that realize the same
function and use the same principles are grouped together. Then their operating
principles, parameter(s) of control, advantages and disadvantages are listed.
For example, the function of preservation by reduction of water activity by
evaporation, different dryers having different operating principles exist. They
include the following:
-
Hot air dryers which functioning is based on the type
of air flow (parallel or co-current flow, counter-current, cross-flow,
center-exhaust flow): Bin dryers, cabinet dryers (tray dryers), tunnel
dryers, conveyor dryers (belt dryers), fluidized-bed dryers, kiln dryers,
pneumatic dryers (pneumatic ring dryers and flash dryers), rotary dryers,
spray dryers, and solar dryers
-
Heated surface or contact dryers which functioning
principle is based on conduction: drum or roller dryers, vacuum band and
vacuum shelf dryers
-
Other types of dryers based on other principles:
microwave dryers, ultrasonic dryers, freeze dryers, etc
Information on advantages and disadvantages of the different
technical solutions are also provided. It consists mostly of a comparison in
energy consumption, rapidity, simplicity, flexibility, controllability,
processing temperature, pressure, which define feasibility, general energy
consumption and effects on foods.
4. The methodology for the search of principles in agro-food equipment design
The sequence of the actions to be realized in this
methodology is given in figure 4.

Figure 4: Scheme of the methodology for the search of
principles in food processing
Compared to the general scheme of TRIZ, the differences are
located in the following points:
-
The tests 2.1 and 2.2 lead the search either exclusively
within the agro-food processing sector by using the database on principles
applied in food engineering, or in the other sectors if inter-disciplinary
transfer of principles is sought. This can be facilitated by the use of
multidisciplinary databases such as in TRIZ-based software when they are
available. The two search paths can also be undertaken simultaneously.
-
Action 4 provides an alternative by reformulating the
standard problem in the case that previously defined standards have not led to
pertinent principles. This reformulation can be done, for example, by
proposing a change in the nature of the product to be processed. This change
supposes the necessity of intermediate or ancillary functions.
-
Action 5 proposes an evaluation of all principles directly
identified by using the database and generated by their modification and/or
combination. This evaluation is proposed in order to eliminate the principles
that are not feasible and to classify the feasible ones taking in account
predefined technical, economical and social criteria. The selected principle(s)
is then considered for further precision in the following step of the design
process (definition of the equipment). Undertaking the evaluation step at the
end of this methodology is a way to free users� mind of the feasibility issue
during the creativity phase.
Examples of application of the methodology
To illustrate the use of this methodology an example on the
search for appropriate principles for an equipment for coconut oil extraction,
and an example on the production of starch from cassava are given. Both examples
deal with the search of the best potential principles for the main function of
separation considering given criteria. At the beginning, we do the hypothesis
that ancillary functions in traditional processes are not necessarily useful
(e.g. cutting, rasping, etc.), and that other principles still unknown in the
coconut oil and cassava industries may improve the traditional processes. We
also suppose that only the database on principles applied in food processing is
available. The results show that the differences in the characteristics of the
products in these examples lead to the identification of some different
principles.
Table 2: Examples of application of the methodology
| Steps of the methodology |
Starch extraction from cassava |
Oil extraction from
coconut |
| Standard problem
|
Separation of molecular size solid that
is hydrophilic and sensitive to high temperature (starch), contained in a
matrix of fibrous solid substance containing water (the cassava root) |
Separation of a hydrophobic
liquid (oil) from a matrix of fibrous solid containing water (the coconut
meat). The final product desired is crude oil (not refined) |
| Standard solution
(Components a and b of the database) |
For both examples, the
database on food processing principles does not contain a standard solution
leading to principle(s) that directly allows the realization f the main
function. There is a need to reformulate the standard problem.
|
| Reformulation of the standard problem
(Components a and , b of the database)
|
The nature of the substances
to be separated can be modified in both case in order to identify existing
standard solutions; and therefore, identify pertinent principles in the
database. In the case of starch extraction, the tuber which is solid, can be
transformed into a dry particulate solid (by a rasping or blending or
crushing operation, followed by a drying process, and finally a separation
by size such as sieving, or by density such as in cyclone), or into a pulp
or a suspension which is a mix of particulate solid and a specified water
content by rasping, blending and adding water (dilution) followed by all
liquid/solid separation techniques. In the case of coconut oil extraction,
an existing standard solution which consists of separating two liquids (the
emulsion made of oil and water also called coconut milk) that are not
miscible is pertinent. However, it requires the realization of a first
separation function to eliminate the solid matrix that contains these
liquids. Once the emulsion extracted, the water is separated from the oil. |
| Standard solutions and pertinent
principles (Components a,b,c,d of the database)
|
a) Separation of particulate
solid of a certain size contained in another particulate solid of a bigger
size (this supposes a first ancillary function of transformation without
change in composition (a size reduction by cutting the solid for example) b)
separation of particulate solids of a molecular size, hydrophilic, from a
mix of particulate solid and liquid (the pulp obtained by ancillary
functions of size reduction such as blending, shredding , rasping or
crushing for example) c) separation of particulate solids of molecular size,
hydrophilic in suspension in an important volume of water (suspension) |
a) Separation of an hydrophobic liquid
contained in a particulate solid with a given moisture content (this
supposes a first ancillary function of transformation without change in
composition: a size reduction by cutting the solid for example) b)
Separation of a hydrophobic liquid from a mix of immiscible liquids and
particulate solid (the pulp of coconut meat obtained by blending, shredding
or rasping for example ) |
| Existing, pertinent principles
(Components c and d of the database) |
a.1) Combination of
pressure, difference in nature, size, and weight to separate the starch from
the fiber and the water (expression by presses, expellers followed by
filtration, sedimentation and weight) as in classical processes a.2)
Principle of pectinolytic enzymes and cellulase to degrade the walls of the
cells that contains the starch followed by separation by size (filtration)
or by weight (sedimentation, centrifugation) a.3) principles of application
of high pressure to degrade the structure of the cell walls, followed by
principle of filtration b.1) principle of separation by size (screening)
preceded by drying to separate the water as in classical dry process b.2)
principle of separation by density using air (cyclone) preceded by drying to
separate the water b.3) Principle of separation by size of the fibrous solid
part by size density or weight (settling) preceded by dilution (adding
water) b.4) Principle of separation by settling accelerated by
electromagnetic field preceded by an ionization of starch molecules b.5)
principle of separation using difference in weight and acceleration
(particulate solid/liquid centrifugation) |
a.1) Principles of pressure (classical
mechanical expression) combined with principle of separation by difference
in nature (hydrophobicity) and in density (sedimentation): classical process
a.2) Principles in a.1 followed by separation by difference in nature,
combined with difference in density and acceleration (centrifugation) a.3)
Principle of release of the oil based on the degradation of the cells of the
coconut meat by high temperature (boiling) combined with principle of
separation by difference in nature (hydrophobicity) and in density
(sedimentation): classical process a.4) Principle of release of the oil
based on the degradation of the cell walls of the coconut meat by high
pressure followed by principle of separation by difference in nature (hydrophobicity)
and in density (sedimentation) b.1) Principle of dissolution based on
difference in nature (hydrophobicity) such as in extraction by solvent (e.g.
hexane), followed by principle of difference in temperature of phase
transition to separate the solvent (distillation): classical process b.2)
Enzymatic attack of the walls of the cells to release the oil followed by
the separation of the residues by difference in nature (filtration) or in
weight (centrifugation). |
| Evaluation and selection of the most
feasible principles using socio-economical, technological, and environmental
criteria) |
Transferable principles: -
Principles involved in a.2 can be interesting economically; however,
biological principles are more difficult to control than the other
principles. - Principle in b.2 is interesting but it has to be preceded by
an appropriate drying principle of the pulp which may increase its cost. -
Principle in b.5 seems to be the most feasible but it has to be preceded by
filtration to separate the fiber. |
The principles which transfer seems to
be viable are the ones used in a.2, a4 and b.2. The same observations as in
the application of these principles for starch extraction are valid |
Conclusion and prospective
A TRIZ-based methodology is developed to help the search for
engineering principles for the design of food equipment adapted to the technical
and socio-economic context of countries where designers are lacking scientific
knowledge in food processing, and limited in investment capacities. The
development of the methodology is based on the adaptation and integration of the
most accessible TRIZ techniques considering the constraints mentioned and the
inherent complexity of some TRIZ concepts which will not be used. The selected
TRIZ concepts are coupled with the collect and rational use of relevant
scientific agro-food processing information. The approach of the methodology
combines the reformulation of a specific problem of principle search into a
standard problem based on the statement of the main function of the equipment to
be designed and the scientific characterization of the product to be processed.
This standard problem simultaneously guide and widen the field of the search to
all potential principles that can be used to realize a given function (e.g.
separation) for the processing of all kinds of products as long as they have the
same characteristics (e.g. particulate solids of given sizes or shapes, or
liquids of specified densities). The standard solution that corresponds to the
standard problem identified is located in the database set up on all principles
involved in agro-food processing. The root of this database is indeed made of
the same data on equipment main functions and products characterization, which
guide the users toward the most pertinent principles and existing applications.
The main functions and categories of food products by geometrical, physical,
chemical and biological properties have been identified in previous study of
unit operations in food industries. The identification of pertinent principles
encourages their transfer from the processing of a product to that of another
one, and their modification or combination to create new ones for the design of
appropriate new equipment considering the predefined technical, socio-economical
and environmental criteria. The development of this methodology is at its early
stage. The integration of more scientific information such as the principles of
hurdle technologies12 into this methodology is believed to further nurture
creativity and the generation of new principles.
This method has been developed in the particular context of
food-processing equipment design, made by multidisciplinary design teams in
developing countries, but it can be used also by SMEs in industrial countries,
in order to re-organize TRIZ databases in relation with their specific
industrial sector. Indeed the working conditions of the design teams are often
the same ones in the SMEs as in the developing countries: a direct utilization
of TRIZ databases is generally to heavy and must be adapted to each industrial
sector. The specific needs of developing countries in terms of low cost, limited
power, availability of raw materials, etc., are only specific constraints having
to be taken into account in the final step of selection of solution.
About the authors
Mireille Totobesola-Barbier, engineer in Agro-food Industries
from ENSIA-SIARC13 in Montpellier, holds a Master�s degree in Food Sciences from
the University of Sciences and Techniques (2002), and in Economics and
Management of Agro-food enterprises from the University of Law and Economics in
Montpellier (1994). She worked as a research associate at Conservation
International in Washington, D.C. (USA) from 1995 to 1997, and at the
international research center for tropical agriculture (CIAT) in Latin America
from 1998 to 2000.
Claude Marouz�, Ph.D., is a researcher at CIRAD. Dr. Marouz� holds a Ph. D.
in �G�nie Industriel� from the Ecole Sup�rieure d�Arts et M�tiers (ENSAM) in
Paris.
Fran�ois Giroux , Professor at the ENSIA-SIARC, is a research Associate at
CIRAD. Pr. Giroux is also the Director of ENSIA-SIARC11 in Montpellier since
1988.
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Footnotes
- French acronyms for � Centre de coop�ration
Internationale en Recherche Agronomique pour le D�veloppement, D�partement
Am�lioration des M�thodes pour l'Innovation Scientifique, Programme Agro-alimentaire
� meaning centre for international cooperation in agricultural research for
the tropics and subtropics, department of Advanced Methods for Innovation in
Science (AMIS), Agrifood Systems Programme
(back to article)
- French acronym for �Conception d' Equipements dans les
pays du Sud pour l'agriculture et l'agroalimentaire, M�thode �
(back to article)
- The technical term � standard problem � is sometimes
substituted by � problem model � or � general problem � (Domb, 2001). The
same is done with � standard solutions �.
(back to article)
- Food processes are very diverse, but careful analysis
shows that they can be broken down into a small number of a series of basic
or unit operations (Earle, 1983). These operations are performed by
different equipment having the required functions. Some equipment can do
various operations or en entire process, they are multifunctional.
(back to article)
- Two function types can be distinguished (Commission,
1990) :
The product�s service functions (those which directly satisfy the users�
requirements) : the use functions, the esteem functions, and to explicitly
define the benefits that is to be brought to the market.
The technical functions of the product�s elements to describe an existing
or envisaged solution.
(back to article)
-
Some unit operations may perform
combination of two or more useful functions. In these cases, it is
recommended to select the most important and relevant function for the
formulation of standard problem. The more careful the definition of the main
function, the more efficient the search of appropriate principles and
definition of specific technical solutions. For instance, the principles of
membrane technology in clarification (separation of impurities),
concentration (separation of water), and preservation of liquid foods
(separation of microorganisms) involve in general a difference in molecular
weight and in pressure. However other principles may be combined to these
two to achieve more efficiently the main function (e.g. for the membrane
separation of microbial cells, spores and/ enzymes, difference in charge
between the particulate substances and the membrane are also used to enhance
the efficiency of the separation by electrostatic repulsion).
(back to article)
- Water activity is the ratio of vapour pressure of water
in a solid to that of pure water at the same temperature (Fellows, 2000).
(back to article)
- Oxidation/reduction potential of food or microbial
substrate (Fellows, 2000).
(back to article)
- Hydrophile-lipophile balance : The ratio of hydrophilic
to hydrophobic groups on the molecules used to characterize emulsifiers
(Fellows, 2000).
(back to article)
- Some solids (for example powders and particulate
materials) are termed � fluids � and can flow without desintegration when
pressure is applied to them. In contrast, solids deform when pressure is
applied to them (Fellows, 2000).
(back to article)
- Lethality is the integrated killing effect of heating
temperature and time on microorganisms (Fellows, 2000)
(back to article)
- Hurdle technologies also known as �combined processes�,
�combination preservation� or �combination techniques� is the concept of
combining several factors to preserve foods. An understanding of the complex
interaction of temperature, water activity, pH, chemical preservtives, etc.
is used to design a series of hurdles (barriers ) that ensure microbial
safety of processed foods (Fellows 2000).
(back to article)
- French Acronym for � Ecole Nationale Sup�rieure des
Industries Agro-alimentaires - Section Industries Alimentaires des R�gions
Chaudes �. ENSIA-SIARC is a training and research Department of the ENSIA
based in Paris. This department focuses on helping food companies in the
developing countries, in the mediterranean and the tropical areas.
(back to article)
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