The laser tachometer is used to verify the speed of the rotating cup of the CIP 10.
The speed of rotation is proportional to the sampling flow rate.
Once the flow rate of the CIP 10 has been calibrated using the calibration bench ARC8525, the internal electronic circuitry of the CIP 10 maintains the rotational speed constant within +/- 3%. Therefore, a simple verification of the rotational speed is all you need, to assure that the CIP 10 is sampling within the desired limits.
It is a foreign notion, to believe that the sampling rate will not be affected by sample dust loading. You must realize that there is no backpressure in this mode of sampling. The air is being sampled constantly due to the rotation vortex created by the spinning foam. The foam filter has such a high “dirt holding” capacity, (several grams) that there is no pressure drop because of the increasing dust load, so no change in the air flow.
Several papers, found in our technical literature library, attest to this concept, as does the fact that the CIP-10 has been cited in an ISO standard for dust sampling for over 25 years.