Design and test of automatic feed system for tray seedlings transplanter

Abstract: The nacelle-type semi-automatic transplanter is the best available technology to punch holes in the plastic film and has been used extensively in Xinjiang, China, but the nacelle-type transplanter had very low efficiency. It had the frequency of less than 40 pieces /min for each transplanting device. The automatic feed system was designed for a nacelle-type transplanter to improve the efficiency of the feeding system of the transplanter, matching with the tray which is widely used in Xinjiang province. It has 128 (16 rows×8 lines) plugs and is made by the vacuum form process. The thickness is 0.6-1 mm, the hole depth is 45 mm, the top width is 31.75mm and the bottom width is 13mm. The tray carrying the seedlings can be moved transversally and longitudinally by the step-displacement unit (SDU) in the feed system. In order to reduce the automatic feed system width of the horizontal direction, and keep plug seedlings from dropping from the plug tray, the machine was slanted at an angle horizontally with the SDU beams at 105°. The seedlings were taken and moved by a turning and position shift style seedlings manipulator (TPSM). The seedlings were dropped in the tube of the flexible chain conveyor feeding mechanism (FCCFM) by the manipulator at the right time. Then the seedlings were transported and put in the nacelle of two different transplanting devices by the FCCFM. The FCCFM was set at the bottom of the feed system. The SDU was set on the top and side of FCCFM, and the TPSM was set on the top of the FCCFM. The seedling transfer was done by the TPSM, which picks up the seedling on the tray side and drops the seedlings on the other side. When the seedling tube is standing still, the manipulator puts the plug seedlings into the seedling tube. With the seedlings tube driven by the flexible chain and rotating to the right side, the seedling tube will go through two types of drop windows -- one is wide, and the other is narrow. When the seedlings tube first goes through the narrow drop seedlings window, only the narrow shutter of the seedling tube is opened and drops seedlings. When the seedlings tube goes through the wide drop seedlings window, all the shutters open, and only the wide shutter seedling tube drops seedlings. The feed system is controlled by PLC, and driven by pneumatic force. The average total air consumption of the pneumatic components is 60.56L/min. The structure of this automatic feed system is independent and does not increase the load on the wheels of the transplanting machine. Its mass is less than 110kg and the cost is also affordable. It can be attached to a new transplanting machine or it can be used with an existing transplanting machine. The "Hong'an #6" pepper seedlings were used to test the automatic feed system, and seedlings were raised from February 25, 2011 to April 25, 2011. At a seedling age of 58d, the average height of the seedlings was 163.06mm; nursery substrates were made of peat, vermiculite and perlite, in accordance with the volume ratio 1:1:1. Compressed air is provided by the laboratory air pump (ZBM-0.1/8), and the air tank pressure was maintained at 0.5 ~ 0.8MPa. The results showed that the seedling feeding speed was increased up to 70pieces/min, the reliability of the system was 98.92%, and the average mass loss of the seedling substrate was 9.26%.