Hot cappuccino anyone ?
(a case study on something but not on TRIZ)

Y. B. Karasik,
Thought Guiding Systems Corp.,
Ottawa, Canada.

Jose M. Vicente Gomila wrote an interesting account about solving a real problem with coffee machine [1]. He claims that the problem was solved by TRIZ. Was it ?

The problem did really contain a technical contradiction (which was obvious). And eventually the problem solvers arrived at a physical contradiction (which was not obvious) but from which a solution was easily seen. However, was this transition from the obvious (technical contradiction) to the not obvious (physical contradiction) accomplished by TRIZ ? Not at all !

Indeed, due to Jose M. Vicente Gomila the problem looked as follows: when parameters of the coffee machine were set to obtain good coffee with milk, then cappuccino was overheated and with bad appearance; when the parameters were set to obtain good cappuccino, then coffee with milk was cold. That was the essence of the problem from the very beginning. Thus, there was no need in searching for a technical contradiction. It lied on the surface. Hence, no TRIZ was applied at this stage except for applying the TRIZ terminology: the conflict was called technical contradiction.

After that adventures began in the best traditions of the "trials-and-errors" approach. Firstly, it turned out that the engineers did not know why the technical contradiction takes place. By analyzing the machine they came to a conclusion that when the parameters were set for good cappuccino the machine produced cold coffee with milk because the venturi tube of the machine sucked too much milk.

(This means that the engineers did not know from the outset how the machine works. Nevertheless they were able to set its parameters. Interestingly, how ? By pressing some buttons ? Did the machine have the parameters menu ? It is not described in the article.)

Anyway, the engineers that had no idea of how the machine works and which nevertheless were chosen to improve it, made a discovery: there is a venturi tube in the machine that sucks both air (if needed for cappuccino) and milk when steam passes through it. The steam also heats the milk.

Since they did not know how machine works, they also, no wonder, did not know the physical principle behind the venturi tube. Instead of learning it first, they decided to just increase the amount of steam passing through the venturi in hope that the more steam would make milk hotter. To their surprise this trial turned out to be an error. The milk remained cold. And here they stuck !

This continued for three months until our valiant hidalgo Don Jose M. Vicente Gomila arrived to their rescue. He turned out to be cleverer than these engineers and first decided to learn how the venturi tube works. For some reasons instead of taking a peek into a relevant text book, he employed the wonder of the contemporary machinery "Invention Machine". The machine led him to the formula of Bernoulli law that governs the venturi tube. In addition, it generated a lot of redundant information such as, for example, the functional diagram of the machine which was not needed in this case. ("Invention Machine" itself, by the way, was also redundant here. If Mr. Gomila did not have the required textbook at hand, he could simply search on the internet for "venturi tube" using, say, Google search engine. It would immediately lead him to a number of web pages where the physics behind the tube operation is described.)

As soon as Bernoulli law behind the venturi tube was learned, the reason of the failure of the engineers' trial became apparent: more steam passed through the venturi meant the higher speed of passage, which, in turn, meant the higher sucking pressure, which, in turn, resulted in sucking more milk.

Bernoulli law also suggested that in order to keep the amount of sucked milk constant, the speed of the steam passing through the venturi has to be constant too. How to achieve this when the amount of the passing steam increases ? Of course, by enlarging the cross section of the venturi.

At this point a physical contradiction eventually emerged: the cross section should be constant and should not be constant. But truly speaking, there was no need in it. The idea of a venturi with a variable cross section suggested itself from the above analysis. Only TRIZ educated people needed a physical contradiction at this point. All others would go to the solution directly !


So, what is Jose M. Vicente Gomila's case study about ? Definitely not about TRIZ. It is rather on why companies abandon TRIZ after employing it for a while. (By the way, Mr. Gomila complains about this phenomenon in his article.)

The companies do so because they realize that what the TRIZ instructors taught them does not work after the instructors disappear. The story presented by Mr. Gomila clearly show why this happens. Because the instructors themselve do not solve problems by TRIZ. They do it otherwise but pretend and present it as applications of TRIZ.

R E F E R E N C E:

1. Jose M. Vicente Gomila, "Hot cappuccino anyone ?", The March 2004 issue of the TRIZ-journal.