Design and experiment of network chain type residual plastic film collector for peanut field

Abstract: Film-mulching cultivation technique is widely used in China due to its advantage of tremendously increasing the yield of crops. In recent years, the application area of film-mulching cultivation technique has expanded to about 25 million hm2. However, the soil and environment pollution associated with its extensive application becomes an issue which needs to be appropriately considered. As a type of typical film-mulching planting crops in China, peanuts attain the average plastic film residual quantity in the main producing areas to 32.0kg/hm2. In general, the residual quantity increases yearly as the plastic file is difficult to dissolve, resulting in the excess of the farmland film residue limit standard for peanut if no effective treatment being involved. Chain-rod type plastic film residue collector has the feature of high productivity, excellent soil removing ability and can collect the underground plastic film, but when it is used to collect residual plastic film for peanut field, there are plastic film leakage, back and twine problems in the process of conveying. Thus, a network chain type residual plastic film collector for peanut field was designed, which had better work performance in collecting peanut plastic film. According to the design of the critical components of the collector, the structural styles, assembly modes and operation parameters of key working parts, including digging shovel, network chain, soil broken roller, double-acting excitation device and collecting film device, were ascertained respectively. The mathematical models of residual film supporting degree and soil passing ability of chain-rod structure and network chain structure were founded and analyzed respectively. The analysis showed that the network chain structure had a better residual film supporting degree but slightly worse soil passing ability when compared to the chain-rod structure, indicating the conveying advantage of network chain structure. Based on the theoretical working pressure calculation, a soil broken roller with the weight of 350 N was demonstrated to smash the clod effectively. The ADAMS software was used to simulate the motion trail of double-acting excitation device, which showed that the amplitude of the excitation device was 25 mm. In order to sort out sticky clod, the structure of second stage network chain was designed on the basis of elevation angle calculation, which found out that the elevation angle should greater than 35?. The hydraulic driven box of collecting film was designed and checked, and the results showed that the distance of hydraulic cylinder mounting holes was 630 mm and the inner diameter of hydraulic cylinder was 30 mm. Furthermore, the working quality of network chain type residual plastic film collector for peanut field was conducted by field experiments. The field experiments showed that when the operation speed of the collector was 1.0 m/s, the digging depth was 100 mm, the linear speed of first stage network chain was 2.0 m/s, the linear speed of second stage network chain was 2.2 m/s and the frequency of double-acting excitation device was 10 Hz, the mean plastic film collecting rate was 91.5% and the clod content was 17.2%, which met the requirements of residual plastic film collecting for peanut field. The network chain could convey the residual plastic film smoothly without any film leakage, back and twine problems during the entire process. Also, the clod cleanup structure performed well and the hydraulic driven box of collecting film was able to discharge the film conveniently and efficiently. Therefore, the methods and achievements in this study provide important references for the design and optimization of relevant residual plastic film collectors.