ThermoFisher, a world leading brand for scientific devices uses SpraySpy® form AOM-Systems. The costumer is using SpraySpy for its R&D work in order to reach new product innovations for its high demanding costumers. Therefore, ThermoFiscer has high requirements for the accuracy of the AOM-Systems measurement device. To secure the accuracy ThermoFisher performed a study to prove the measurement results given by the device.
Two different inspection measurements (done by the costumer):
First Measurement with droplet generator:
ThermoFisher used a TSI /MSP (Monodisperes aerosol generator Model 1520) drop generator. Based on the flow rate µl/min and the frequency it is possible to calculate the expected droplet size, starting at 20 µm. Comparing the theoretical drop size with the SpraySpy measurement result gives the SpraySpy accuracy.
The author knows that this method is not perfect but a reliable and practical way of analysis the accuracy of the SpraySpy device. The picture 1 shows the set-up of the SpraySpy and the drop generator. Table 1 shows calibration curve of the study from ThermoFisher. In the calibration curve the blue dots are the theoretical droplet size given by the droplet generator (accuracy +/- 1%) and the red dots are the SpraySpy measurement result.
Therefore the SpraySpy measurement results are evaluated to be accurate starting from 20µm onwards. To analyse the accuracy of the SpraySpy system below 20MM it was necessary to have a second measurement.
Second reference measurement with an atomizer:
As a study for the droplets below 20µm ThermoFisher using a pneumatic atomizer (picture 2) for a reference. This atomizer is known for a fine atomization. The Table 2 shows the drop size distribution of this atomizer. The distribution shows a smooth bimodal curve starting at 1µm and with the peak at 15,5 µm, which fits the expectations well.
Knowing that the SpraySpy system measuring accurate from 20µm onwards (compare Table 1) and having the realistic measurement result (compare table 2) for droplets between 1 and 15,5 µm it is a way to define the overall accuracy of SpraySpy for droplets between 1 and 50 µm.
For ThermoFisher this is the proof that the SpraySpy system is measuring even very fine drops from 1 µm onwards accurate.