Design And Implementation Of Biological Safety Cabinet Control Alarm System

Biological Safety Cabinet is one type of exhaust cabinet that is primary used for thebiological safety protection of biological laboratory.Biological Safety Cabinet isolatesoperator who works in biological laboratory from the environment of biologicalexperiment,so that the cross-infection between experiments and operator can be avoided.The researches of Biological Safety Cabinet are almost based on theory in the domesticwhich most are focused on the flow model of Biological Safety Cabinet.There are fewresearches on the practical application and system alarm of Biological Safety Cabinet. For theabove-mentioned current situation,this thesis aims on design and implementation a controlalarming system of Biological Safety Cabinet, which meets the Pharmaceutical industrystandard of the People’s Republic of China YYO569-2011,YY-T0664-2008,YY/T0709-2009.At the end of this thesis, the control alarming system of Biological Safety Cabinet is testedaccording to the Pharmaceutical industry standard of the People’s Republic of China.According to Pharmaceutical industry standard of the People’s Republic of China, thisthesis carries on the demand analysis to the control system of Biological Safety Cabinet. Thisthesis analyses the process of the control system of the Biological Safety Cabinet on the basisof its flow’s model. On the basis of this analysis, the key points of control process ofBiological Safety Cabinet are as follows: flow velocity sensor collects the flow data; theparameters adjustment of fan is based on this data; the fan controls the air flow. According torelevant national standards of Biological Safety Cabinet, this thesis carries on the demand analysis to the alarm system of Biological Safety Cabinet. The alarm system includes air flowalarm system, lifetime of air filter alarm system, state of the window alarm system anddischarged air alarm system.In terms of hardware design, on the basis of analysis, the processing unit includesmicrocontroller and watch dog. There are flow velocity sensor, temperature sensor,windowstate sensors and pressure sensor around the processing unit. The execution Units of controlsystem includes fan and driver circuit. The alarm system includes voice components and lightcomponents.On the basis of analysis, the software system utilizes the pipe and filter architecture. Thesystem includes sensor data unit, data processing unit and action execution unit. The functionof sensor data unit is data output. The processing of sensor data unit is a Digital filterprocessing of the data from the vertical airstream flow velocity sensor, horizontal current flowvelocity sensor, temperature sensor and pressure sensor.The data processing unit processesthe data that sensor data unit outputs. It transforms the data of flow velocity,temperature,window state and pressure to the data that includes control data of fan and alarmdata. The fan control unit adjusts parameters of fan according to the control data of fan, sothat the vertical airstream flow will be adjusted. The alarm unit executes the alarm actionaccording to the alarm data of flow velocity, pressure, lifetime of air filter and window state.According to relevant national standard, this thesis does the test of control system andalarm system. The test measures the airstream flow velocity in Biological Safety Cabinet, inorder to confirm whether the velocity data keeps within the recommended limits ofPharmaceutical industry standard of the People’s Republic of China YYO569-2011.Thefunctional validation of flow velocity, lifetime of air filter, window state alarm and pressure isexecuted on the basis of design requirement.