Structured Innovation: TRIZ for Product Improvement

Using Functional Analysis for Product Innovation

. . . Continuing the series on Structured Innovation . . .

Members of My Executive Council (MEC) had been working on and learning of the application of TRIZ for almost a year and understanding its use in various industries.  Although not totally proficient enough to classify themselves as experts, some of them were eager to learn advanced concepts, especially Josh. He had been very active in not only looking for TRIZ opportunities but also sharing examples with his customer and suppliers.

Recently, Josh visited one of his old sailing buddies and shared the example of how TRIZ had been used in the application of a company logo to a ship’s funnel.  His buddy had originally kidded him when he heard the idea, but then challenged Josh to see if the same methodology could be used on a different problem.  He reminded Josh of an earlier conversation they’d had in days gone by, when they’d been sailing.  “Remember how we always wished that the pre-heaters (heat exchangers) we had on ships could have been simpler? Josh had to test his memory muscles to recall:

  • Temperature changes caused pipes to expand which lead to leakages, especially at the cover-plate interface gasket
  • And the pipe baffles made it difficult to clean the pipe surfaces; the baffles were required to prevent pipe vibration and sagging.  They were, however, useful for directing the flow of the oil.

Could TRIZ be used to improve upon that design?”

Josh discussed the problem with their TRIZ consultant, Henrietta and now decided to share this issue at this meeting with his MEC members.  To help everyone understand what he was talking about, Josh passed out a couple of pictures he had pulled from his old books (Fig 1 and 2). He went on to explain that a heat exchanger is a device that allows heat from a fluid (a liquid or a gas) to pass to a second fluid (another liquid or gas) without the two fluids having to mix together or come into direct contact.  On ships this type of heat exchanger is used to pre-heat engine cooling water; heating steam flows through the set of metal tubes while water passes through the sealed shell that surrounds them.

HeatExchFig1HeatExchFig2

 

Heat exchangers were not unique to the marine industry, so if TRIZ methods could help redesign these pre-heaters, other industries could also potentially benefit from the improvement.

Josh posed the challenge to the MEC group by stating the following contradictions:

  • I want the hangars/baffles and I don’t want the baffles.
  •  The end plate helps compensate for pipe length variation with temperature changes, but it creates additional complexity.

On cue, Josh looked to Henrietta, “Is there not something else within TRIZ that we could apply to improve this product?”

While Henrietta had not been keen on introducing other tools to the MEC group at this stage, she thought it a good opportunity to introduce Functional Analysis to them.  She also thought that reviewing this example with the group would give them a flavor of functional analysis.

She began, “For a given product or process to work, it typically requires many functions.” She went on to explain that a product or process can be described in terms of its parts and respective functions.  An automobile, for example, is something that satisfies the function ‘to transport people.’ A full functional description has three parts: a subject, a verb and an object. For the automobile, this is expressed as

CAR

TRANSPORTS

PEOPLE

(subject)

(action verb)

(object)

“To begin the process” she continued, “start by completing the following three steps:

  1. identify the system components and
  2. provide descriptions of the relationships between those individual components of the complete system.
  3. collect the information about the positive and negative aspects of these inter-component relationships in the form of what (subject) does what (verb) to what (object).

In keeping with the example, she listed out the main components of the system (heat exchanger):

  • Shell                                  Incoming fluid to be heated (cold water – in this case),
  • Tube-sheet                       Baffles
  • Pipes (carry steam)        Outgoing fluid (hot water)
  • End-cover

In describing the relationships and outcomes she went on to explain that the basic functions could include the following:

Pipes heat the cold-water as it flows through the shell and comes out (hot-water) at the other end.  Since the pipes expand with heat, the Pipes also tend to move the Tube-sheet (this is an undesirable function).

Taking another functional relationship:

  1. Shell transmits the cold-water, and
  2. Shell supports compensator
  3. Shell holds Tube-sheet
  4. Pipes heat cold-water (by carrying steam through them)

Additionally there are some auxiliary functions that are not the main function of the heat exchanger but are useful to know to get the big picture of the ‘system’:

These last few have been stated as SUBJECT performs some ACTION on the OBJECT.

The MEC group listened to Henrietta but with baffled expressions. She said, “You can see why I was hesitant to cover advanced tools at this meeting.”

However, upon insistence from the group, she continued, “People new to functional analysis find this aspect of the problem formulation quite un-natural and difficult.  The language is quite different from the language we use on a daily basis.   We need to define the ACTION appropriately to ensure that the SUBJECT changes or preserves something about the OBJECT. It is a time-consuming process since we need to ensure that all relevant inter-component relationships are systematically considered.

Furthermore, we need to determine whether these actions are ‘beneficial’ or ‘harmful’ thus leading to the formulation of a distinct problem to be solved.  Effective identification of all such ‘negative’ functional relationships within a system is essential to the successful deployment of TRIZ Function Analysis methods.  Using graphical representation sometimes makes it a bit easier to understand.

When improving a product/system, the undesirable (harmful) effects need to be determined.  At this point Henrietta asked the members to recall the definition of Ideal Final Result (IFR)

Benefit / (Cost + Harm)

She then stated it a bit differently: A does something to B.   If it is harmful, let’s get rid of it.  If it is useful, determine whether it is OK as-is or whether it needs to be improved? This helps us understand a complicated situation and focus in on exactly what needs to be improved.

Recognizing that the user of the product (in this case, the marine engineer) is generally more interested in the product’s function (heat the water) than the product (heat exchanger) itself it follows that if it is possible to achieve this function without certain components of the ‘system’, the overall system will benefit. This benefit usually takes the form of a lower cost of production/ operation.

This idea of improving the ‘system’ by preserving the function while removing components is one of the product evolution trends known as Trimming.  In TRIZ terms, this means that the IFR is: that the system performs the function without the presence of the product or component with the harmful effect.

Continuing with this train of thought, after conducting a complete Functional Analysis and identifying individual problems, in terms of their effect on the overall system, they would need to be ranked and prioritized.  This is an iterative process till all combinations are thought through and evaluated.  In the heat exchanger example, it might indicate that trimming first the End-cover and then the baffles would be most beneficial to the overall exchanger system.  We could then look at how to prevent the Tube-sheet motion inside the Shell if the end-cover is eliminated, and then, how to prevent the pipe vibration if the baffles are eliminated.

One solution is shown by a u-tube heat-exchanger (Fig. 3).  Josh passed around another picture he found on the Internet.  It uses u-tubes instead of the straight tubes and the shell is in the form of a closed end cylinder. This gives tubes the freedom to expand freely at the curved end.  The complete tube assembly can be pulled out for ease of cleaning.  This trimming of the end cover has thus eliminated a couple of the harmful effects, while retaining the ‘benefits’ of the original design.  And since the whole tube assembly is removed for cleaning, the baffles are not much of a hindrance in the cleaning

HeatExchFig 3HeatExchFig2

 

This was an example of how functional analysis was used to understand the beneficial and harmful interactions and how trimming was used to find a better solution.

Henrietta concluded the session by thanking Josh for creating a situation that forced the group to learn a new tool of TRIZ. She ended the meeting with a suggestion that the group should decide if they would like to learn these advanced tools and to look for fresh cases to bring to the next meeting. They all left feeling exhilarated that they were able to  understand a complex situation in relatively simple terms in such a short period.

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