Design And Experimental Study On Mobile Soil Rotary Steam Disinfection Machine

Healthy and favorable soil environment was an important guarantee for the cultivation of high-quality vegetables.And soil disinfection was one of the effective ways to prevent continuous cropping obstacles.It was becoming increasingly popular among vegetable growers,because it could control soil-borne diseases effectively and did not produce any chemical contaminants.By combining the mechanism of high-temperature steam disinfection,with the requirements of a variety of mechanical operations,an appliance was designed to disinfect soil with steam during rotation and cultivation,and related performance tests were carried out.The main research content was as follows:(1)The basic working principle,overall structure composition and key component design of mobile soil rotary steam disinfection machine were analyzed.Through the theoretical analysis and calculation,the overall design and structural design of the mobile soil rotary steam disinfection machine were completed.(2)Through the analysis of the heat balance,the steam power required for the soil disinfection to 60? was 87.78 kW,when the soil was 120 cm in width deep 15 cm in depth.While the steam generator outlet pressure of the steam sterilizer was 0.6MPa and the temperature was 158.86?,the steam power of the steam generator was 97.35 kW and the system loss was 0.61 kW,which could meet the heat demand of soil disinfection.(3)A steam boiler control system with STM32 as the control core was designed.The temperature control compensation was added on the basis of the traditional steam pressure control;the design of the system hardware and soffware was completed..(4)Four performance parameters,namely the pressure of water vapor,walking speed of the tool,diameter of the sterilized capillary,and the distance between the tubes was selected,to verify the field test.The pressure was selected 0.2,0.3,0.4,0.5 and 0.6MPa in total 5 levels.The corresponding saturated steam temperature for each pressure level was 120.24,133.56,143.64,151.87 and 158.86?;the speed was selected to be 0.38,0.42,0.46,0.5 km/h in total 5 levels;the diameter of the sterilized capillary tube were 4 levels of 5,10,15 and 20 mm;the tube spacing were 3 levels of 180,240 and 300 mm.The experiment compared single-factor disinfecting temperature effects at different levels to select the optimal combination.(5)The plot experiments showed that under the steam pressure of 0.6MPa,the temperature of 158.86?,and the rotary working speed of 0.42 km/h,15 cm depth of soil temperature can reach 62?,respectively,when carried out under the treatment of the capillary tube diameter at 15mm and separation distance of 180mm.This study provided not only a reference for further improving the performance of soil steam disinfection,but also a choice for the farmers using the soil steam disinfection system.