MODELING INVENTIVE PROBLEMS
Problem 16. Gathering granules used
to collect oil
One way to collect oil spilled on the
surface of the water is to dispense porous, oil-absorbing granules. The
problem then arises: how should the oil-saturated granules be gathered?
Consider the following inventions:
Invention 47. Creating a pile
surface on plastic material
To obtain a
pile surface on a plastic material, rotating brushes are immersed in
softened plastic, creating extended fibers connected to the brush
needles. After cooling, the fibers are broken away from the needles.
The plastic adheres to the needles, however, and the machine must be
stopped and cleaned, or a complicated process for cleaning during
operation must be contrived.
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Alternatively, fine ferromagnetic powder can be poured onto the
softened surface, and then extended using an electromagnet. The
powder remains in the congealed plastic without interfering with its
use. This yields an additional effect: by magnetizing discrete
portions of the electromagnet and turning the current on and off in
accordance with a defined scheme, the design of the pile surface can
be controlled. |
Invention 48. Polishing the inside
surface of a closed vessel
| It is often necessary
to polish the inside surface of a closed vessel (such as a Dewar
flask). To
accomplish this, the vessel can be filled with an abrasive substance
containing ferromagnetic additives. Abrasive motion is then
provided using a traveling or rotating magnetic field. |
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Invention 49. Separating small
workpieces from abrasive powder
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Small workpieces can
be ground by stirring them in a drum with an abrasive mass, then
separating them from the abrasive material. For magnetic workpieces,
this is easily achieved using magnetic separation. Often, however,
the workpieces are nonmagnetic.
In this case, the abrasive grains can
be magnetized by adding ferromagnetic particles to the source
material while it is being manufactured. |
At first look, problem 16 seems difficult.
After reviewing inventions 47 through 49, however, the solution idea is
quite obvious: introduce ferromagnetic particles into the oil-absorbing
granules, then use a magnet to collect them.
The solutions used for inventions 47
through 49 apply to the problem of collecting oil-absorbing granules
because the problems described are similar in nature -- in other words,
they can be represented with a similar model.
Modeling -- i.e., using a simplified
diagram to represent a situation -- is one of the most effective ways we
have to study and understand the things around us. Often, operations
(such as mathematical calculations) that are difficult or even impossible
to perform with real objects become quite manageable if the actual system
is replaced with a model. Typically, a model denotes specific features we
are interested in and thus may not correspond to reality with regard to
other features. For example, a reduced-scale model of an airplane might
be an accurate structural representation, but it cannot fly. A model can
look very different from the thing it represents: a mathematical model of
a process (represented by a set of equations) provides reliable
information about, say, the behavior of a gas flow, but doesn’t look at
all like a gas flow.
In general, the procedure for working with
models is as follows:
1. A model representing the required
feature(s) is built.
2. The necessary transformations are
performed; results are obtained.
3. The obtained results are transferred to
the "real" object or situation.
In TRIZ, various models are used that
reflect the basic elements and patterns of the evolution of technological
systems -- in particular, building, analyzing and transforming functional
models called SF or Su-Field models (from a combination of the
words "substance" and "field"). The area in TRIZ that deals with these
models is called SF or Su-Field Analysis.
Let’s build a model for the problem of
collecting oil-absorbing granules in a manner similar to how we would
describe a chemical reaction.
According to the problem description, we
have a substance, S1, that is difficult to manage (collect). Our goal is
to find a way to make it more manageable:
The solution to the
problem will look as follows: introduce a ferromagnetic substance, SF,
and a magnetic field, FF, so that SF can exert some
influence over S1:
If we connect the above two diagrams with
an arrow symbolizing the transition to a solution, we will get this
"formula" for the solution:
This clearly describes the essence of the
solution. We had a substance S1 that was barely receptive to
desired change. We turned the situation around by introducing a special
substance-field "couple" that included a ferromagnetic powder (SF)
and a magnetic field (FF) to achieve the desired changes.
Obviously the above formula describes inventions 47-49 as well.
There might be other couples (i.e., other
substance-field combinations), however, that also solve the problem
nicely.
Invention 50. Increasing the
hydrodynamic lift of a float
| The hydrodynamic lift
of a float must increase sharply as the surrounding temperature
rises. This is achieved by introducing inside the float a substance
which has a low boiling point; the volume of the float increases
abruptly when the substance reaches its boiling temperature. |
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Invention 51. Arc welding with
thermite
To obtain a
quality welded joint, a strong current must be used. Not all welding
devices provide the necessary power, however.
For quality
welding using low current, an exothermal mixture (thermite) is
introduced into the joint and the flux layer. The thermite burns away
during welding, considerably increasing the heating power in the welding
zone. To introduce thermite in difficult-to-access areas, a fluid
mixture is used.
Inventions 50 and 51
have their own formula:
There is an unreceptive substance, S1. In
order to achieve required changes, we transition to a system that includes
a thermal field, FTh, with a substance, S2, that
responds to the thermal field.
Models consisting of substances and fields,
and the interactions between them, are called SF models. A functioning
system can be modeled, as a minimum, with two substances and a field.
This minimum SF model includes:
- an "article" (S1) representing an object
that is changed or influenced in some way
- a tool (S2) representing the
means by which S1 is changed or influenced
- energy (F) representing the interaction
between S1 and S2
Examples of SF models:
A vacuum cleaner cleaning a carpet
S1 - carpet (article)
S2 - vacuum cleaner (tool)
F - cleaning (mechanical field)
A person painting a wall
S1 - wall (article)
S2 - person (tool)
F - painting (chemical field)
Of course, in reality a situation is likely
to be more complex than this; such situations are described by a set of
different SF models. As mentioned earlier, a complete SF model includes
three elements: two substances and a field. If one or more elements is
missing, the model is incomplete, indicating the presence of a problem.
Accordingly, to solve the problem we must complete the model by
introducing the missing element(s).
The following definitions are used to
describe a problem situation:
When we convert a verbal problem
description into a SF model, we omit all unnecessary information and focus
on the essence of the problem: what we have (substances, fields, actions)
and what we want to change or add. SF modeling reveals why a problem
exists (the model is incomplete, for example). For this reason, aside from
providing a convenient method for graphically representing a problem, SF
modeling helps us penetrate to the root causes of the problem, and offers
effective ways for transforming the system.
The SF solution formula
serves as a prompt for what should be done (what to add) to a system: a
substance, a field1 or both. It doesn’t
suggest what elements these should be, however. To obtain a technical
solution the problem solver must identify the appropriate substances and
fields. It is highly recommended that the search start with fields rather
than substances, as there is a limited number of fields to consider. There
are five basic fields that should be explored:
Me
- mechanical
Th
- thermal
Ch -
chemical
E
-
electrical
M -
magnetic
Most fields are associated with
corresponding "preferred" substances: a magnetic field works with
ferromagnetic particles or permanent magnets; a chemical field works with
various catalysts or inhibitors; an electrical field works with charged
particles; etc. Therefore, when you are looking for a field you are
actually looking for one or more substance-field couples that can solve
the problem.
ASSIGNMENT
1
Try to
apply SF modeling to the following problems:
Problem 17. Brazing pipes across
large gaps
When erecting
large-panel buildings, the pipes embedded in individual panels must be
linked. This can be done by brazing them together; however, due to
assembly discrepancies, the gaps between the pipes may reach several
millimeters, and brazing requires small, capillary gaps to hold the
solder. What can be done?
Problem 18. Inflating a satellite
In 1960, an inflatable satellite was
put into orbit. The satellite measured 67 cm when empty and folded, and
30 m when inflated. Accordingly, it was launched into the orbit folded
and was inflated once reached the orbit. How was the satellite inflated?
Problem
19. Measuring carbon dioxide
A climatrone
is a special chamber used for studying plant behavior under various
conditions. Conducting experiments in a climatrone requires the precise
measurement of carbon dioxide, which is fed to the plants in very small
amounts. A device such as an electronically-controlled valve is too
complicated for this purpose, and does not provide the required
accuracy. Any suggestions?
ASSIGNMENT 2
Find your own examples of SF models.
NOTES:
1. In TRIZ, a "field"
is any kind of energy that can act on an object (e.g., a thermal field,
acoustical field, etc.). The definition of field is broader than in
physics, where only four fields are defined.
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