Company N, which develops and manufactures various medical devices, was working on the development of a new model of their diagnostic imaging equipment. Ms. A of the company's development department shared her development story with us:
"Diagnostic imaging equipment is an important medical device that is indispensable for early detection and localization of diseases by imaging the condition inside the body. This equipment requires not only high performance but also quiet operation because it is used near patients. So, we put an effort to develop a low-noise model to differentiate it from competing products on the market."
Ms. A selected and tried several fans from fan catalogs that had lower sound pressure level ratings than the one used in the current model at the time.
"Despite being the same fan, when mounted on actual equipment, fan noise levels vary depending on factors including the component layout in equipment. We measured the sound pressure level of these fans when mounted. The results were better than the one used in the current model but not as good as expected from their catalog ratings, and none of them could satisfy our cooling performance requirement," she recalled with a sigh.
The limited development time wouldn't allow her and the development team to mount and measure many fans. It seemed they had no chance of finding a fan that could meet both the low noise and cooling requirements in time, and she was stuck.
Seeking a solution, Ms. A consulted a SANYO DENKI sales representative, whom she had known from another project. To her excitement, he promised that he could offer a perfect solution.
At a later date, as promised, the sales representative visited Company N again with an Airflow Tester to measure the system impedance of the diagnostic imaging equipment under development.
"To select the optimal fan for particular equipment, you need to know the system impedance* of the equipment. The intersection of the system impedance curve of equipment and the fan's P-Q performance curve is known as the operating point of the fan. Once you obtain this information, you can find the fan's airflow, static pressure, and sound pressure level when mounted on the equipment," explained the SANYO DENKI representative.
After spending a few days reviewing the measurement results, the sales representative visited Company N again to propose a fan.c "SANYO DENKI proposed a fan, denoted as 'B' in the figure. Our current fan 'A' has better catalog ratings than fan B. As you can see in the figure, however, fan B has higher airflow, static pressure, and even lower noise at the operating points!" said Ms. A in excitement.
She was very intrigued by the proposal and requested a sample for evaluation right away. The in-house evaluation results were satisfactory and the sound pressure level dropped by 10 dB at once. Following that, they soon decided to use the proposed fan. As a result, Company N successfully developed and launched the new diagnostic imaging equipment featuring a significant noise reduction.
* System impedance: Resistance to the flow of air within a device
Ms. A was really impressed by the Airflow Tester, which realized the optimal fan selection.
"This Airflow Tester really helped shorten the development time, visualizing the system impedance of the equipment. This tester, I thought, would make our future fan selection much easier and more efficient, freeing us from worrying about the conventional time-consuming fan evaluation with it mounted on actual equipment. Our company judged that this Airflow Tester could help us a lot in our future housing design and officially made the decision to purchase one. We will definitely make use of this tester in our future developments," she said delightedly.
