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The Design of Pressuring and Conveying Snow Removal Machine on Multi-span Greenhouse Roof ? Keqiang Yu Engineering College Shanxi Agricultural University Taigu, Shanxi, China e-mail: Shuangxi Wang Engineering College Shanxi Agricultural University Taigu, Shanxi, China e-mail: AbstractSnow on the greenhouse roof has a great effect on light transparence and heat loss. It brings bad effect on plant growing also affect greenhouse structure strength. In order to reduce the impact of snow on the greenhouse industry, comprehensively consider greenhouse roof status, such as snow thickness, temperature conditions and so on, we design the pressuring and conveying snow removal machine. It is a subservient, efficient, inexpensive and environmental program for snow removal on greenhouse roof in future. Key words- pressuring and conveying; multi-span greenhouse roof; snow removal machine; design I. INTRODUCTION Modern horticultural facilities have a booming trend and the height of its scale is getting bigger and bigger in China. However, the winter continuous snow covered with greenhouse roofing, not only affect photosynthesis of indoor plants and make plants not to get the best growing. But also it affected the greenhouse pervious to light quality, heat preservation. Then this wastes a lot of energy. What more, snow influence the overall strength and rigidity of greenhouse, resulting in a large number of greenhouse was cashed. Therefore, how to effectively eliminate snow of greenhouse roof has become an important subject 1. At the present time, there were three commonly used methods on the snow removal of the greenhouse roof. That is method of artificial snow, method of melt snow and method of machinery snow. Artificially snow removal needed more labors, very long time and wastes materials. Snowmelt method can improve the efficiency of focusing on snow removal, but causes a series of pollutions to the environment and shortcomings to building greatly 2. In addition, it is a large one-time investment cost and does not fit to small greenhouse fruit and vegetable production 3. Due to those, this paper introduced the design of pressuring and conveying snow removal machine on multi-span greenhouse roof. II. STRUCTURE OF THE EQUIPMENT. This equipment is aimed at a span of 6-10 meter of glass, plastic board roofing in multi-span greenhouse and load-bearing beams of other types of plastic film triangle roofing multi-span greenhouse. The equipment mainly contain six parts, balance device, snow sweep device, power and transmission device, conveying-snow device, pressuring snow device, control device. The whole structure of this equipment is shown in figure 1. According to control device internal sleeting sensor, when measuring snow amount, it calculated snow thickness and made snow removal machine opened timing, it also can be started manually. When the equipment started to work, the motor in power and transmission device made the wheel moving forward. While the other motor in sweep-snow device droved the snow sweep dish rotating, it made snow on greenhouse roof slipped off to gutter. Then the scrapers in pressuring-snow device would scrape and gather snow to the gutter. Meanwhile the next scraper pushed snow to device inside the pressing-snow spaces, the pressuring-snow device pressed snow into snow blocks. Later scrapers pushed snow blocks from other end of pressing-snow device to the conveyor belt. At last, snow blocks transported to vehicle through conveyor belt. ? Figure 1 Integral structure of the equipment schematic drawing 1-Balance device 2-Snow sweep device 3-Power and transmission device 4-Conveying snow device 5-Pressuring snow device 6-Gutter 7-Multi-span greenhouse roof 8- Load-bearing beam A. Snow sweep device The snow sweep device structure is motor, gear transmission system, V-belt, pulley, shaft, device frame, snow Natural Science Foundation of China?30771241?) 807 978-1-4244-9439-2/11/$26.00 2011 IEEE sweep dish, dish sets, guide plate, bearings. Its structure is shown in figure 2. ? ? Figure 2 Snow sweep device structure schematic drawing 9-motor 10-gear transmission system 11-V-belt 12-pulley 13-shaft 14- device frame 15-snow sweep dish 16- dish sets 17- guide plate 18- bearings There were 4-6 snow sweep dish in unilateral side greenhouse roof, its height value was from between 400-150mm ordinal according to the proportion. The motor power in this device outputted to snow sweep dish nearest the gutter with gear transmission system, the rest of the adjacent snow sweep dish used V-belt driver. Between each adjacent snow sweep dish installed guide plate, its can scrape snow glued in snow sweep dish and also can prevent snow splashes in the process of snow sweep dish rotating. In order to reduce the weight of snow sweep dish, dish sets used polycarbonate materials. About 5cm long polyamide brush circular sleeve was matching every elastic fabric dish sets respectively. When the snow sweep device started to work, the motor outputted power to nearest snow sweep device dish through pinion unit, the rest of the adjacent snow sweep dish used V-belt driving. Its structure is shown in figure 3. All snow sweep dish rotating in same direction will make snow from greenhouse roof gathered to gutter. ? Figure 3 Snow sweep device power transmission schematic drawing 9-motor 10- gear transmission system 11-V-belt 12-pulley 13-shaft 14- device bracket 15-snow sweep dish B. Balance device This balance device is made up of balanced stents, rubber material ring, hollow shaft, bearings and bushings .Its structure is shown in figure 4. Bearing in this device fixed on both ends of the hollow shafts. And bushings fitted in central position of hollow shafts. Wearing the rubber material bearing ring to the bearing outer ring turned the bearing into rubber wheel. Then bushing would be welded at the bottom of balanced stents. Balanced stents installed on bracket of snow sweep device together through angle iron. In order to keep the whole snow removal machinery of balance and shift part of weight snow sweep device to the loading beam, two rows of columns of bearing rubber wheels worked loading beams which located in greenhouse roof both adjacent sides of gutter. Figure 4 Balance device structure schematic drawing 19- Balanced stents 20- Rubber material ring 21- Hollow shaft 22- Bearings 23- Bushings C. Pressuring snow device This device contained three driven sprockets, roller chain, scraper, fine shaft, fine bushings, driving sprocket, thick shaft, roller, scraper frame, bearings, shaft, base plate, choke plate, V-belt, V-pulley and spring. Its structure is shown in figure 5. ? ? Figure 5 Pressing snow device structure schematic drawing 24-driven sprocket 25-roller chain 26-scraper 27-fine shaft 28-fine bushings 29-driving sprocket 30-thick shaft 31- roller 32-scraper frame 33-bearings 34-shaft 35-base plate 36-choke plate 37-V-belt 38-V-pulley 39-wheel 40-returning spring The device of power came from motor of the conveyer device. Then power was delivered through the V-belt to the driving sprocket. Scraper and scraper frame matched between themselves in place. Returning spring was fixed in the centre of them. It can make scraper keeping stretched out of scraper frame. Its structure is shown in figure 6. 808 ? Figure 6 Scraper and scraper frame structure schematic drawing When scraper moving to bottom of pressing snow device, because the base plate is convex which made scraper up shifting, returning spring was tensile gradually. When scraper moved away from the base plate, then returning spring contraction made scraper back to initial position. In this device driving sprocket and 3 driven sprockets connected with roller chain. Two roller chains connected with hick shaft which had been matched to thick shafts. And then we should decide how many scrapers and scraper frames would be fixed. In a circle of whole chain installed scraper frame evenly, meanwhile scrapers installed in scraper frames. Putting choke plate to the both sides of whole device. Finally base plate was installed in the below of whole device. The motor put power to V-pulley through V-belt and made driven sprocket rotating coupled with driving sprocket rotating by roller chain. Snow in gutter would blow into the pressing space which was formed with scraper, fine bushings, base plate and choke plate located in both sides by outstretched scraper. Then fine bushings and scraper moving horizontally with roller chain, it made pressing snow space turned small gradually, so snow were pressed into blocks of snow. Blocks of snow at the bottom of the pressing snow device were pushed to conveyor belt by scrapers. Snow blocks transported to vehicle through conveyor belt continuously. D. Power and transmission device Power and transmission device located in both ends of snow sweep dish and basically contained walking wheel, gear reducer, motor, and V-belt driving. Its structure is shown in figure 6. Due to motor outputted a high speed. The high speed will be reduced through the gear reducer. Then power gave to walking wheel through the V-belt driving, it made the whole device moved forward. E. Conveying snow device Conveying-snow device mainly consisted of roller, conveyer belt, tension pulley, shaft and bearing, support frame, wheel, “I”- connecting rod, motor, convey belt and flat pulley. Its structure is shown in figure 7. F. control device Control system of control device had an outside station, a microcontroller and computer. Outside station included several sleeting sensors. They can calculate snow thickness according to the snow, and then control the timing of open and close 4. Figure 6 Power and transmission device structure schematic drawing 41- Walking wheel 42- gear reducer 43- motor 44- V-belt driving ? Figure 7 Conveying snow device structure schematic drawing 45- Roller 46- conveyer belt 47- tension pulley 48- shaft and bearing 49-support frame 50-wheel 51- “I“ connecting rod Because length of greenhouse is quite long, it needed very long conveyor belt. For the purpose of transportation and removing convenient, each segment of conveyor belt was 3m long. They were linked one by one at one end of pressing snow device by the “I“ shape link rod. Conveyor belt and pressure snow device matched at one end of base plate in pressing snow device, its structure is shown in figure 7. III. CONCLUSION Compared to traditional methods of snow removal, method of machinery snow is an effective, low-cost snow removal program. This pressuring and conveying snow removal machine on multi-span greenhouse roof should pay attention to some questions as followed: (1) This equipment is suitable for the triangle roof greenhouse only. (2) The strength, stiffness and transmission power of the equipment must be calculated strictly in the design. Meanwhile, firm structure and driving reliability of machine needed to assur