Medical Technology: Nozzle Gauging

In this application, correct assembly of a sight-feed nozzle has to be checked. The image displays a correctly assembled nozzle with the relevant measuring lines.

Such a nozzle is used for medical infusions. The sieve inside the nozzle acts as a protective guard against coagulations or other particles that must not enter the patient's blood circulation. It is therefore extremely important that this sieve is mounted correctly.

Several measurements are used to verify this:

• Distance of the sieve bottom from the top of the nozzle (about 35mm) must not differ by more than 4mm.
• Width of the sieve must not be below a certain value.
• Distance of the sieve from the wall must not differ by more than 1mm on both sides.

The nozzle is captured with two cameras, one horizontal, the other vertical, in order to measure deviations in any direction.

The complete inspection takes about 0.75 seconds on a Pentium 100, including a position adjustment, which uses a reference edge to compensate for varying positions of the object with respect to the camera.