Design And Experiment Of Piglet Feeding System

The lactation stage is the key link in the growth process of pigs.In the feeding process,due to the lack of milk and lack of milk of lactating piglets,the development and death of piglets occur from time to time,which has brought serious losses to farmers.Therefore,meeting the nutritional intake of lactating piglets and feeding or supplementing lactating piglets in time are important measures to improve the survival rate of piglets.At present,China mainly adopts artificial feeding,CO feeding or foster feeding,semi-automatic feeding and other methods in piglet feeding,which has the disadvantages of high labor intensity,low degree of automation and low feeding efficiency.In order to reduce labor intensity and improve feeding efficiency,this subject designs a piglet feeding system,develops an automatic control system with PLC as the core controller,and realizes the automatic control of water,temperature control,mixing,feeding and cleaning in the process of piglet feeding.The main research contents and results are as follows:(1)The overall scheme design of piglet feeding system.Based on the comprehensive analysis of the working principle,design requirements and technical indexes of the current piglet feeding device,the overall scheme of the piglet feeding system was determined.The piglet feeding system is mainly composed of mechanical structure and control system.The mechanical structure comprises a milk preparation device and a milk conveying device.The milk preparation device is composed of water supply solenoid valve,piglet milk preparation tank,mixer,mixing motor,etc;The milk conveying device is composed of feeding solenoid valve,feeding pump,breast feeder,conveying pipeline,circulating solenoid valve and drainage solenoid valve.According to the design requirements,the key parts were designed,calculated and selected,and the main technical parameters of the mechanical structure of the piglet feeding system were determined.(2)Numerical simulation and optimization of stirrer in piglet milk tank.Taking the double-layer paddle agitator in the piglet milk preparation tank as the research object,using the research method of CFD numerical simulation and response surface analysis,taking the rotating speed,layer spacing,paddle angle and distance from the bottom as the design optimization parameters,and taking the mixing power,mixing time and average temperature rise rate as the response indexes,a four factor and three-level orthogonal simulation experiment was designed,and the regression model of the response indexes was established,Through the response surface regression model,the optimal parameter combination is 80 rpm,the layer spacing is 170 mm,the blade angle is 30 °,and the distance from the bottom is 100 mm.Compared with that before optimization,the stirring power is reduced by 27.08%,the mixing time is reduced by 70.15%,the average temperature rise rate is increased by 9.57%,and the turbulent flow energy cloud diagram distribution and temperature cloud diagram distribution are significantly better than those of the primary model.According to the optimization results,the motor and reducer are selected.(3)Numerical simulation and optimization of milk conveying pipeline.Taking the milk delivery pipeline as the research object,the effects of pipe diameter,pipeline material,milk inlet temperature and pipeline velocity on the pressure field and temperature field in the pipeline were studied by CFD numerical simulation.According to the simulation results,the basic parameters of the transmission pipeline are determined,that is,the pipeline material is PPR material,the pipe diameter is 6 branch pipes(outer diameter 25 mm,wall thickness 2.8mm)and the pipeline flow rate is 0.8m/s.The feed pump is calculated and selected according to the pipeline flow rate.(4)Design of piglet feeding control system.The design of piglet feeding control system is mainly divided into hardware design,software design and human-computer interaction interface design.The hardware composition of the control system mainly includes Siemens s7-200 smart,ae04 analog input module,MCGS touch screen module,temperature acquisition module,relay module,switching power supply,liquid level acquisition module,solenoid valve and other devices.According to the functional requirements,the relevant components are selected and the PLC input / output points are allocated,and the hardware connection diagram is drawn.The ladder diagram program of piglet feeding control system is compiled by using step-7 microwin smart programming software.The piglet feeding system has two control modes: automatic and manual.In the manual mode,the breeder can manually control the water supply,mixing,heating,circulation and drainage through the touch screen.The automatic mode is divided into two modes: automatic feeding and automatic cleaning.The breeder completes the setting of relevant parameters on the touch screen,such as feeding water volume,feeding temperature and feeding time.The system will complete automatic operations such as automatic water supply,automatic temperature control,automatic mixing and automatic circulation according to the parameters.Finally,the man-machine interface is designed by using MCGS configuration software.The man-machine interface is mainly divided into main interface,manual control interface,alarm interface,operation log interface,real-time curve interface and user management interface.(5)Performance test of piglet feeding system.The prototype of piglet feeding system was made,and the debugging and performance test were carried out.Firstly,the prototype was used to carry out the temperature control accuracy test,and the final stable temperature of piglet milk preparation tank was measured when the feeding temperature was set at 30 ℃,40 ℃,50 ℃ and 60 ℃.The average relative error between the set value and the test value was 0.91%,and the temperature control accuracy was maintained at ± 1 ℃;Secondly,the temperature control stability test was carried out when the set temperature was 45 ℃,and the stability of milk temperature in piglet milk preparation tank with time was analyzed.The standard deviation of temperature measurement samples was 0.2263,and the coefficient of variation was 0.499%;Then,the temperature distribution measurement experiment of piglet feeders was carried out,and the temperature distribution of piglet feeding points in 28 incubators was measured when the set temperature was 45 ℃.The temperature distribution of each feeding point met the feeding requirements of piglets.The temperature distribution trend of the test value was consistent with that of the simulation value.The total average relative error between the test value and the simulation value was5.26%,and the accuracy of the simulation model was high;Finally,the pressure distribution of piglets was measured.The test shows that the device can normally realize the functions of water supply,mixing,heating,circulation and drainage,and the pipeline pressure and temperature at each feeding point can meet the feeding requirements of piglets.