No-till planting method is widely used for maize-wheat two-crops-a-year area in the North China Plain.However,cruel soil conditions,especially the large number of maize stalks which are hard to cutoff covering,often c...No-till planting method is widely used for maize-wheat two-crops-a-year area in the North China Plain.However,cruel soil conditions,especially the large number of maize stalks which are hard to cutoff covering,often cause an unsatisfying planting quality.Based on the authors’previous investigation,ultrahigh-pressure(UHP)waterjet is capable to solve this problem and obtain qualified seedbeds.Thus,a UHP waterjet assisted furrow opener for no-till seeder was designed.Field tests showed that double-disc furrow openers worked well with UHP waterjet,since the sharpened disc blades could help to cut soil and residue,meanwhile,minimize soil disturbance.Response surface method(RSM)was used to investigate the relationship among forward speed,waterjet pressure,jet impingement angle and anti-blocking performance(stalks cutoff ratio and depth of soil cutting),and a Box-Behnken three-factor design was used to identify the optional operation parameters.A total of 17 combinations were conducted,and the results showed all three operation parameters significantly affected anti-blocking performance.Stalks cutoff ratio and depth of soil cutting increased with the increase of waterjet pressure,jet impingement angle,and decreased with the increase of forward speed.The optimization analysis indicated that when waterjet pressure was 267-280 MPa,jet impingement angle was 80.2°to 90.0°and forward speed was 4.00-4.42 km/h,the overall performance of UHP waterjet assisted double-disc furrow opener for no-till seeder was maximized.Stalks cutoff ratio could be above 95%and no blockage occurred.This study may provide a new approach and reference for the anti-blocking technology of no-tillage seeding.展开更多
Belt conveyor is a kind of important equipment for transporting coal mines, and is also a facility for connecting various processes. It plays a vital role in the supply of raw materials. At present, people have used b...Belt conveyor is a kind of important equipment for transporting coal mines, and is also a facility for connecting various processes. It plays a vital role in the supply of raw materials. At present, people have used belt conveyors in the mining, production, transportation and processing processes of coal mines. It not only has a large transportation volume, but also can be applied in complex working environments. The equipment has a strong carrying capacity and supports transportation by the Bureau of Parks and Roads. This paper gives an overview and analysis of the material blocking protection device of belt conveyor, looking for a proximity switch, combining with the problems encountered in the test, and based on the working principle of belt conveyor, puts forward effective improvement measures of the device, increasing the weight of the detection door in the transformation, and improving the use efficiency.展开更多
基金financially supported by the Special Fund for Agro-scientific Research in the Public Interest from the Ministry of Agriculture,China(Grant No.201503136).
文摘No-till planting method is widely used for maize-wheat two-crops-a-year area in the North China Plain.However,cruel soil conditions,especially the large number of maize stalks which are hard to cutoff covering,often cause an unsatisfying planting quality.Based on the authors’previous investigation,ultrahigh-pressure(UHP)waterjet is capable to solve this problem and obtain qualified seedbeds.Thus,a UHP waterjet assisted furrow opener for no-till seeder was designed.Field tests showed that double-disc furrow openers worked well with UHP waterjet,since the sharpened disc blades could help to cut soil and residue,meanwhile,minimize soil disturbance.Response surface method(RSM)was used to investigate the relationship among forward speed,waterjet pressure,jet impingement angle and anti-blocking performance(stalks cutoff ratio and depth of soil cutting),and a Box-Behnken three-factor design was used to identify the optional operation parameters.A total of 17 combinations were conducted,and the results showed all three operation parameters significantly affected anti-blocking performance.Stalks cutoff ratio and depth of soil cutting increased with the increase of waterjet pressure,jet impingement angle,and decreased with the increase of forward speed.The optimization analysis indicated that when waterjet pressure was 267-280 MPa,jet impingement angle was 80.2°to 90.0°and forward speed was 4.00-4.42 km/h,the overall performance of UHP waterjet assisted double-disc furrow opener for no-till seeder was maximized.Stalks cutoff ratio could be above 95%and no blockage occurred.This study may provide a new approach and reference for the anti-blocking technology of no-tillage seeding.
文摘Belt conveyor is a kind of important equipment for transporting coal mines, and is also a facility for connecting various processes. It plays a vital role in the supply of raw materials. At present, people have used belt conveyors in the mining, production, transportation and processing processes of coal mines. It not only has a large transportation volume, but also can be applied in complex working environments. The equipment has a strong carrying capacity and supports transportation by the Bureau of Parks and Roads. This paper gives an overview and analysis of the material blocking protection device of belt conveyor, looking for a proximity switch, combining with the problems encountered in the test, and based on the working principle of belt conveyor, puts forward effective improvement measures of the device, increasing the weight of the detection door in the transformation, and improving the use efficiency.
