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.