Study on the Operating Conditions of Micropump Components

Abstract:

The micropumps driven by AC, DC brush, DC brushless or stepper motors can be used in pharmaceutical industry. The particular property of such pumps is magnet coupling between motor and pump. The aim of the analysis has been to investigate the operating conditions for bearing in such pump during flow of water, oil and glycerin – water solution and to investigate the dependency of the glycerin – water solution flow upon the outlet – inlet pressure difference and upon the speed of motor driving pump. It has been also investigated the possibility of application for NdFeB – NdFeB magnet assembly in the magnet coupling. The loading of pump are connected of flow resistance determined by outlet and inlet pressure difference, speed and temperature of pumped liquid, geometry and material properties of pump elements. The driving motor is loaded by mechanical resistance of pump element motion either. The moment – pressure difference relationship and flow – pressure difference – speed relationship have been made for water and oil and then approximated equation for them have been elaborated. With help of such equation scheme of moment – pressure difference relationship and flow – pressure difference – speed relationship for glycerin – water solution have been made for various values of glycerin strength. The model of pump bearing has been elaborated using Finite Element Method. Auxiliary mathematical equations have been utilized for calculating sliding velocity in bearing and loading force. The obtained contact pressure in bearing has been presented in the article. The model of magnet coupling has been elaborated with use of Finite Element Method and presented in the paper. Dimensions of model are closed to the one used in original pump. It has been observed that for up to 50% glycerin - water solution the moment – pressure difference relationship and flow – pressure difference – rotational speed relationship are very similar to these in the water case. With increasing of solution strength above 50% they start to be more different. Values of contact pressure nonlinearly increase with driving moment value increasing. Calculated values of torque excited values given out by manufacturer with about 20%. Calculated value of decoupling torque for NdFeB – NdFeB magnet assemblies is greater more than 50 % comparing SmCo – NdFeB case.

• Periodical: Advanced Materials Research (Volume 1051)
• Pages: 813-818
• DOI: https://doi.org/10.4028/www.scientific.net/AMR.1051.813
• Online since: October 2014
• Authors: Adam Rylski, Krzysztof Siczek*
• Keywords: Bearing, Finite Element Method (FEM), Glycerin-Water Solution, Magnet Coupling, Micropump

References

[1] Information on http: /www. micropump. com.

[2] Information on http: /www. chinamicropump. com.

[3] Information on http: /www. fizyka. umk. pl/~lab2/tables/viscosit. html.

[4] Ansys Documentation.