Design Of A Pressure Automated Control Installation For Microsphere Granulator

Nowadays, medicament microsphere is widely used in many fields such as cytology, immunology, microbiology, molecule biology and clinic diagnosis & treatment and so on. As a kind of new technic of medicament preparation, process for microsphere preparation is more and more taken into consideration. Therefore, it becomes a hotspot that developing a set of installation from which microspheres with good sphericity as well as low standard deviation are prepared. Capillary vibration method (CVM) is a kind of process for microsphere preparation; it is especially suitable for daily laboratory use or small batch preparation. Installations based on this method have occurred in foreign countries, but there are no such ones in China. The sticking point of installations based on CVM is the pressure control system, vibration & dispersing system and the matching of the two systems.There was a set of installation for microsphere preparation, which required manual work for pressure control. As a result, the repeatability is not good and meanwhile the operator of the installation must be a veteran. So the pressure automated control installation is designed to control the air pressure in the reservoir vessel with rations, make the process of pressure control quick and stable, achieve better repeatability, lighten the operator's work and reduce the human caused error at the same time.At first, the fluid characteristic of the air both in the inflating process and deflating process is studied. And then, in this work, a set of pressure automated control installation based on feedback theory is established, which is used in microsphere granulator. High speed electro valves, a Micro Controller Unit (MCU) and an air pressure sensor which conform a complete feedback loop, together with software arithmetic, make the drug liquid spout steady-going. After matching pressure automated control installation and vibration & dispersing system, the configuration of microsphere granulator is fixed. Tested by experiment, in 25℃, using alginate of 2% concentration for microsphere preparation, when standard deviation of diameter of microspheres is less than 10%, microspheres with diameters from 710μm to 1210μm are prepared, and velocity of flow per spout can be more than 0.6 l/h.