热风干燥脱水蔬菜控制系统的设计DESIGNOFCONTROLSYSTEMFORHOTAIRDRYINGANDDEHYDRATINGVEGETABLES摘要蔬菜的脱水保存时间长，运输方便，卫生状态好，维生素等营养素的损失少。目前我国在食品行业方面，蔬菜脱水的地位极其重要。蔬菜脱水可以利用多种技术来实现，其中热风干燥最为普遍的一种技术。它的优点在于所得到的蔬菜的数量多，同时相较于其余方法成本较低，生产速度也很快。本文研究的热风干燥系统的热风源是由锅炉加热的蒸汽，通过翅片热交换器和植物脱水用感应风机传送到烤箱。本论文的主要内容如下：蔬菜脱水车间的为了实现自动化控制蔬菜脱水的流程，利用西门子的PLC进行运作，以方便实行电气自动化。感应风扇的速度由频率转换器控制，高温蒸汽的流动由电控制阀控制。为了满足蔬菜脱水过程的管理要求，决定了选取符合实际的方法，采购专业电气元件设备，设计电气系统的线路图。在蔬菜进行脱水的过程中，温度管理非常重要。本文设计了PID控制法来控制热风温度。编译PLC程序，使用WinCC软件设计人机接口，实时显示蔬菜脱水装置的温度和湿度值，监视生产操作，根据各种蔬菜设定适当的温度和湿度值的品种。结果表明，所设计系统符合整个工艺流程的需求，可以在一定程度上降低能耗。关键词：PLC；可编程控制器；PID；热风脱水蔬菜IAbstractThedehydratedstoragetimeofvegetablesislong,thetransportationisconvenient,thesanitaryconditionisgood,andthelossofvitaminsandothernutrientsisless.Vegetabledehydrationaccountsforalargeproportioninthemarket.Hotairdryingisaprocessingmethodwithhighyield,loweconomiccostandhighproductionefficiencyinvegetabledehydrationproduction.Thehotairsourceofthehotairdryingsystemstudiedinthispaperisthesteamheatedbytheboiler,whichistransmittedtotheoventhroughthefinheatexchangerandtheinductionfanforplantdehydration.Themaincontentsofthispaperareasfollows:thecontrolsystemofvegetabledehydrationworkshopisconstructedbySiemensPLC,whichrealizestheautomaticcontrolofvegetabledehydrationworkshopequipment.Thespeedofinductionfaniscontrolledbyfrequencyconverter,andtheflowofhightemperaturesteamiscontrolledbyelectriccontrolvalve.Inordertomeetthemanagementrequirementsofvegetabledehydrationprocess,theappropriatemanagementschemewasdetermined,therelevanthardwareequipmentwasselected,andthewiringdiagramofsystemhardwarewasdesigned.Whenvegetablesaredriedbyhotair,temperaturemanagementisveryimportant.Inthispaper,PIDcontrolmethodisdesignedtocontrolthetemperatureofhotair.CompilePLCprogram,useWinCCsoftwaretodesignman-machineinterface,real-timedisplaythetemperatureandhumidityvalueofvegetabledehydrationdevice,monitortheproductionoperation,andsetappropriatevarietiesoftemperatureandhumidityvalueaccordingtovariousvegetables.Theresultsshowthatthetemperaturecontrolofthecontrolsystemfullymeetstherequirementsoftheproductionprocess,improvesthedegreeofautomationandsavesenergyconsumption.KeywordsplcprogrammablecontrollerpidhotairdehydratedvegetablesII目录摘要..................................................................................................................................................IAbstract..........................................................................................................................................II1绪论..............................................................................................................................................11.1课题研究背景及意义............................................................................................................11.2国内外研究现状........................................................
