Design Of Organic Acid Spray Device Based On PLC And Configuration Software Control

How to extend the shelf life of the pig carcass is widely concerned by the pig slaughtering enterprises.The organic acid spraying is considered to be an effective method to solve the microbial contamination of the pig carcass,however the research on this process is mostly on the technological parameters,such as the concentration of organic acid and the temperature of the solution.To solve the problems that immersing and artificial spraying result in high cost,onerous labor and unsuitability of industrialized production,this study,collaborated with JiangSu food group,designed an organic acid spraying device which use PLC as processor and configuration software as Human-Machine Interface.The device can realize automatic spraying,automatic solution supply,real-time monitoring of container liquid level and other functions.In this paper,pig carcass of Duroc x Yorshire x Landrace(DYL)were used as test materials.To verify the feasibility of the device,the related experiments were carried out on the basis of hardware selection and control system programming.The specific work of this study is as follows:(1)Elaborated the specific function of the lactic acid spraying device,and put forward the general design plan.According to the automatic slaughtering line in the group,a scheme for synchronous spraying of the carcass is proposed to design the lifting mechanism for driving the spraying of the nozzle.Because of the production environment of the workshop,two-fluid air-atomizing nozzles are selected as the spray elements of the device.In the light of the number and flow characteristics of nozzles,selecting the model of air compressor,spraying pump,supplying pump,PLC and touch screen,and related electrical components was treated as the basis of allocating the input and output signals of the spraying device.(2)The ladder diagram control program of PLC was developed on the SIEMENS STEP 7 MICRO-WIN platform,and the ladder diagram of the spraying control and the supplying control were drawn in accordance with the assigned input and output points.The spraying control program can make that pig carcasses automatically are sprayed after entering the spraying zone,and the automatic reset function was set up to improve the working stability of the device.The supply control program can realize the control of water intaking,pumping and drainage,which can be automatically ended by PLC through the output signal of the liquid control switch,to greatly saved the time of the operator and improve the efficiency.The touch screen control program was developed on the MCGS7.7 embedded configuration software platform,and the variables are defined in the configuration software,linked with the corresponding PLC registers,to establish the channel.The initial window and the batching window are designed,in witch the operation attributes of buttons and indicators were defined,to control water intaking,pumping and drainage for enhancing the interactivity of the device.(3)Considering that running state of the device could make a difference to spraying effect,the nozzle type(A),the spraying pressure(B),the running time of the cylinder(C)were selected as the discussion factors,and the average rate of coverage(M)and the average weight of coverage(N)were taken as the evaluation indexes of the orthogonal test.The analysis of variance and difference found that the factors affecting the the average rate of coverage(M)from large to small were A,C and B,and A had highly significant effect(P<0.01),C had significant effect(P<0.05),B had no significant effect.The factors affecting the average weight of coverage(N)from large to small were A,B,C,and A was significant(P<0.05),the other effects were not significant.Through the analysis,the nozzle type of flat head nozzle,the spraying pressure of 0.15 MPa,the running time of the cylinder of 3.1 s were the optimized parameters with the average rate of coverage(M)reaching over 80%and the average weight of coverage(N)reaching 0.0119 g/cm2.At the same time,the test of bacteria reducing showed that this device could effectively reduce the number of microorganisms on the carcass surface of pigs(P<0.05),which were sprayed before entering cold storage.