Study On The Low Temperature Plasma Sterilization Equipment

The development and improvement of sterilization technology have played a very important role in people's growing medical requirements. In the early times, people adapt the methods of chemical treatment or heat-treat to sterilize items, while there exist many limitations such as long time, low efficiency, high energy consumption, environmental unfriendliness and so on. Development of electronic technology has spawned a number of new sterilization techniques. Among them, low temperature plasma sterilization technology has become more favorable and its effects have gained widespread recognition, due to energy-saving, environmental protection, highly efficiency and it's like.Plasma state is the fourth state of material, which possesses many special properties. Usually a material may appear solid, liquid and gaseous, while it could turn into a plasma state if enough energy is provided. In the state of plasma, material ionized into ions and electrons which continuously absorb and release energy, resulting in many molecules or atoms on the metastable state, and thus shows some characteristics which doesn't exist in normality. Plasma sterilization uses this principle to ionize the hydrogen peroxide steam into hydroxyl radical, hydroxyl peroxide radical and excited state of hydrogen peroxide. These metastable particles contain with high activity, can easily kill bacteria and viruses on the surface of an object. And during the transition from metastable to steady state these particles will release ultraviolet light which can strengthen the sterilization effect. Due to the requirement of low temperature sterilization environment, this subject adopts the international commonly used method, low-pressure glow discharge, to generate plasma.The state of gas discharge may change with different gas pressure, temperature, drug concentration and sterilization items, leading probably to discharge interruption. Aiming at this problem, digital closed-loop control scheme based on DSP which can stabilize the discharge process by PID algorithm is presented. In this paper, the mechanism and process of plasma are described and studied and a plan of plasma sterilization has been worked out. Furthermore, software and hardware design of the control system of a prototype has been completed combined with embedded system design concepts.At present, the plasma sterilization equipment is mainly imported. Hospitals' demand for sterilization equipment is huge, they usually work offline together and be equipped with workers. It costs a lot on the management and maintenance of so much equipment and the equipment resource utilization is low, causing the difficulty of discovering problems in time during the process of sterilization. With regard to this situation, this paper put forward an innovative solution combined with IOT(internet of things) technology. That is getting the working states of every device, collecting related data in the terminal equipment for centralized display, and responding to the completion of sterilization task and then issue a warning. Meanwhile, the software could distribute tasks equally according to the usage of equipment, so as to extend the life of the equipment and improve the work efficiency. This paper developed a corresponding communication protocol, completed online monitoring of the equipment.