Talking about the requirements of grain storage on warehouse design
Zhang Lailin? Zhu Tongshun Li Zhao Zhao Yingjie Li Jianfeng
(Henan University of Technology 450052)
Abstract In this paper, on the basis of summarizing the experience of designing and constructing grain warehouses for many years, from the point of view of the warehousing process, it describes the requirements for safe grain storage in terms of the structure of the warehouses, the setup of doors, windows and apertures, the performance of the warehouses, and the ancillary facilities of the warehouses, etc., and puts forward corresponding suggestions or improvement measures for the problems in the design of the warehouses. It also puts forward corresponding suggestions or improvement measures for the problems existing in the design of silos.
Keywords: grain storage, warehousing process, warehouse design, grain warehouse
The construction of warehouses to meet the requirements of grain storage is the first condition for good grain storage, it should have the following performance: first, from the warehouse structure to meet the needs of safe grain storage, with good grain storage performance, can maintain the quality of stored grain, grain in the warehouse is not moldy, insect erosion; second, in and out of the grain link to achieve mechanization, automation, grain in and out smoothly and quickly; third, the grain in and out of smooth and quick; third, the grain in and out of the warehouse is the most efficient way to store grain. Grain in and out of the smooth, fast; third grain storage facilities are perfect, able to monitor changes in grain conditions at any time, with a variety of means of grain protection, can ensure the safety of grain storage.
1 warehousing process on the importance of grain storage safety
1.1 warehousing process and civil engineering design
Warehousing workers should be in the construction of warehouses before the warehousing process on the structure of the requirements of the barn, barn civil engineering must meet the requirements of the warehousing process, the two sides to cooperate with each other *** with the completion of the design of the barn building and construction of the building. Warehousing staff to participate in the whole process of building warehouses, found that the problem of timely improvement.
1.2 Warehouse construction must meet the needs of grain storage
Warehouse for grain storage, storage process is reasonable or not on the storage of grain safety has an extremely important impact. In the planned economy era, due to the system and block division of reasons, infrastructure and storage and transportation in two lines of management, the formation of the design and storage process disconnect, so that the warehouse lacks the necessary storage facilities and means of treatment, the result is that: First, the construction of a good new silo appeared to be "built after the change of" the phenomenon; Second, the lack of grain storage facilities, such as the 18 mechanized backbone of the library built silo group Library built in the silo group of grain storage over the winter on the top of the hanging wall bad grain accidents, so that some silo group idle for a long time, resulting in a waste of silo capacity. Therefore, the popularization of deep storage grain technology, to strengthen the storage process and supporting facilities research is of great significance.
2 safe storage of grain on the warehouse structure requirements
2.1 warehouse must be strong and durable
Grain silo is different from other buildings, in addition to bear the wind load, snow load, earthquake and other loads, but also to withstand a considerable amount of grain side pressure, especially to consider the different types of grain, different stacking methods, different loading heights of the grain side pressure on the wall of the warehouse to prevent the wall from cracking; Also consider different types of grain, different loading height on the vertical pressure of the floor, to prevent the floor subsidence.
Because of the different types of grain, wheat, rice dispersion is different, the same stacking height of grain on the barn wall strength requirements are different. The same variety of stacking method is different at the same time, the grain on the barn wall force is also different. In general, it is not advocated that the silo is overloaded with grain. If the bulk warehouse overloading grain, can be in the loading line height from the warehouse wall 1m on the surface of the grain, according to the "trapezoidal" up table loading grain; due to packaging warehouse walls can not withstand the side pressure, can not be directly used as a bulk warehouse, if you want to load bulk grain, you can only use the packet to surround the way of stacking, otherwise there will be problems. Such as July 6, 1999 informed the powder factory in a county in Jiangsu Province, the packaging warehouse directly used as a bulk warehouse, the grain is not loaded on the warehouse collapse of the accident. The dynamic load of flowing grain is usually several times its static load, the self-flowing silo type should also pay attention to the unloading load on the cylinder and the role of the warehouse facilities, asymmetric unloading or arching grain suddenly collapsed will make the cylinder cracks, damage to the cylinder facilities and other accidents.
Early warehouse loading height is low, according to the retaining wall formula to calculate the warehouse body force. Existing silo loading height increased, although the thickness of the wall may not increase, but a large number of use of steel, cement, and in the wall to increase the number of ring beams, so that the strength of the wall is greatly increased. At this time can not simply calculate the strength of the wall according to the retaining wall formula, but according to the lateral force transfer, row structure calculation.
The roof of the underground warehouse shall not have pits, rodent and ant burrows, and tamped with clay in layers. There can be no tall trees within 10m from the arch foot. The protective slope of the underground warehouse should maintain the natural slope as far as possible, planting turf to prevent landslides, and rainwater should be prevented from roaming on the hole.
2.2 Warehouse doors, windows, holes set
Warehouse doors, windows, holes set to consider the grain in and out of the warehouse process and the convenience of daily management, warehouse door height, width should be considered for the storage of grain machinery in and out of the size of the warehouse windows, the number of windows and the way to open the warehouse in line with the ventilation, replenish the warehouse needs. Hardening of the barn floor to be able to withstand the fan and in and out of the grain machinery walking.
2.2.1 Warehouse windows should be less, the size of the warehouse to meet the needs of replenishment
Early warehouse windows are mainly used for lighting and natural ventilation, and the existing warehouse are equipped with lighting, air ducts and fans and other facilities, the windows are mainly used for dispersal (ventilation), dust or grain replenishment. If the design is still based on the warehouse window per room, the number of windows is too large, which directly affects the warehouse insulation and airtight performance. It is recommended to halve the number of windows, barn door above the rain lap, custodian switch inconvenience, no windows; windows should be a single fan open or open, should not be used double casement windows, sliding windows; window size to meet the needs of the warehouse outside the mechanical grain replenishment.
2.2.2 Warehouse door should be less, should avoid the sun
Warehouse door direction and the number of both the food in and out of the fast and convenient, but also consider the safety of grain storage, but also take into account the library of road planning and railroad lines for loading and unloading convenience.
In production, usually toward the warehouse side of the wall back to load grain, the floor is covered with ducts, 10 ~ 15m conveyor can not turn around in the warehouse, reduce the number of warehouse doors can reduce construction investment, but also improve the airtightness of the warehouse. Therefore, it is recommended that: small-span reserve warehouse warehouse door design on one side, and avoid direct sunlight location; large-span warehouse on both sides of the door and according to the asymmetric type arrangement, including the main warehouse door design some large, conducive to machinery in and out of the other warehouse door to do some small, conducive to the sealing of the warehouse door.
2.2.3 Warehouse grain checking small door or manhole settings
As the instrument detection can not completely replace the artificial sensory testing, the custodian often into the warehouse to check the grain, warehouse grain checking small door or manhole settings should be convenient for custodians to enter and exit.
Shallow grain silo type such as cottage warehouse each warehouse (granary) only need a grain inspection door. Vertical ladder at the door is not conducive to the custodian to carry things up and down the grain pile. It is recommended that the grain inspection door be located on the north side of the warehouse or at the mountain wall, and an inclined ladder be set up outside the warehouse to facilitate the custodian to carry items up and down. Some grain storage in the platform with a hut is better, can be used to store grain storage information and cards, check grain utensils.
Deep grain layer silo type such as shallow round silo, silo must be set up at the top of the manhole, its location near the gable, set up a ladder on the inside of the cylinder wall, easy to custodian up and down. The bottom of the tall silo should also be set into the manhole, for empty warehouse cleaning and equipment maintenance. Into the manhole structure should be convenient for the custodian to open, but also to facilitate the sealing of grain storage. Between the shallow round silo should be set up in the gable end of the pedestrian trestle, in order to facilitate the custodian to walk.
Early shallow round warehouse manhole is located in the center of the roof, not conducive to grain inspection. Currently most of the grain depot for renovation, will be an outlet into the air, into the dual-use. That is, some silos have used the basket for people up and down, due to the basket up and down when the rotating movement occurs, unsafe, so now basically do not use.
2.2.4 The setting of the grain door
The bulk of grain on the wall of the silo has a huge side pressure, flat-bottomed silo door generally does not directly bear the side pressure of grain, but by the grain plate (door) to bear. The lower part of the grain baffle (door) is equipped with a discharge port for grain out of the bin before the grain baffle (door) is opened. Grain baffle (door) has a variety of forms, grain baffle board placed although inconvenient, but out of the grain is convenient; grain baffle door switch is convenient, but from the unloading mouth of grain, there are still some grain blocking the grain baffle door, can only be used with suction grain machine or manual grain solution, not as convenient as the grain baffle board. Shallow round barn should be used to stop the grain door, cottage barn is also recommended to choose to stop the grain door. If the choice of grain baffle, in the wall of the U-shaped fixed groove should be left with a gap, in order to facilitate the placement and removal of grain baffle. The use of "V" shaped food blocking plate, the inner wall of the door should be above the top cover, otherwise it will be in the food blocking plate to form a triangular deep hole, coupled with the dim light in the warehouse, the custodian of the food checking the formation of safety hazards.
2.3 Warehouse storage performance
Grain is both heat-sensitive substances, but also hygroscopic substances, high temperature, high humidity environment is easy to cause a decline in the quality of the grain, caused by the grain heap of local or even the whole bin of grain heat mold. Therefore, the barn is required to have good heat insulation, moisture and airtight performance.
2.3.1 Moisture-proof leakage performance
The warehouse roof, walls, floor, ducts and other places of leakage or moisture, very easy to cause moldy grain moisture, must strengthen these parts of the leakage, moisture-proof treatment, so that it meets the needs of food security storage.
Commonly used waterproofing materials are polymer modified asphalt roll-roofing (coating), synthetic polymer waterproofing roll-roofing (coating), fine stone waterproof concrete, asphalt-based waterproofing coatings, rigid waterproofing layer, flat tiles and so on. In the moisture layer arrangement should try to make the water vapor in the access road to do "difficult to come out easy", generally set in the high temperature side of the insulation layer, in order to avoid moisture condensation inside the insulation material, reduce the effect of heat insulation. Shallow round storage of grain, not easy to pour warehouse, pay more attention to the warehouse leakage, moisture problems. For grain silos, moisture and seepage control is equally important, especially shallow round silos unloading grain corridor and settlement joints should be handled according to seepage control standards.
The outer side of the upper exhaust fan hole of the silo should have a rain cover to avoid rainwater infiltration, and the inner side has a closed door to avoid air leakage during fumigation.
2.3.2 Thermal insulation performance
The barn enclosure, especially the roof of the room type barn is the main way of heat transfer from the outside world into the barn, in order to maintain the low temperature of the grain stored in the barn, it is necessary to improve the barn's thermal insulation effect.
There are two ways to insulate the warehouse, static method and dynamic method, commonly used in the production of static method of insulation. (1) additional solid material insulation layer on the roof, the use of roof material layer of thermal resistance and material heat storage, improve the structure of the thermal insulation, thereby reducing the average temperature and temperature fluctuation range of the inner surface of the roof in summer; (2) additional ventilation layer on the roof, the use of ventilation layer shading the sunlight, so that the roof becomes a two-time heat transfer, to avoid the sun to radiate directly on the enclosure, and at the same time in the role of the wind pressure, the natural ventilation to take away the mezzanine layer in the Heat, reduce the barn outside the hot air on the roof, reduce the temperature inside the barn; (3) the barn with heat-insulating materials ceiling, the penetration of heat into the roof above the ceiling, while installing exhaust fans on the mountain wall, the use of low-temperature ventilation at night, and constantly the ridge of the triangle under the accumulated heat discharged out of the barn, to improve the insulation effect of the ceiling; (4) in the roof brushing, laying of tin foil, or spraying reflective coefficient of the large paint, reflecting the sun's Radiant heat, can reduce the warehouse temperature 2 ~ 5 ℃, such as the U.S. Shield reflective coating, Liangbao special heat insulation coating, but the heat insulation effect is closely related to the degree of cleanliness of the coated surface, brushing 1 ~ 2mm gypsum slurry effect is also better, economic simplicity, sunlight resistance, resistance to scouring; (5) color steel roof can be used in the color steel buckling board plus rock wool, composite polystyrene board, the inner roof spray polyurethane and other ways of heat insulation, installation of compression plate to pay attention to the butt plate seams of the Heat insulation and airtight treatment; (6) warehouse wall increase thermal insulation, in shallow round warehouse concrete wall outside the spacing layer left 10cm, and then add 15cm thick aerated concrete block, or outside the wall spray polyurethane 30 ~ 50mm thick, outside the wire mesh, and then brush the mortar layer of protection, bungalow warehouse can be in the hollow rib wall directly filling polystyrene board insulation; (7) where the warehouse does not affect the warehouse building and work of the warehouse area such as the Kunming Treasury, Liuzhou State Reserve Bank, you can Planting wall-crawlers or pole high crown plants to reduce the direct exposure of sunlight on the warehouse.
In order to improve the thermal insulation capacity of the warehouse, we should use materials with relatively small thermal conductivity, such as expanded perlite, glass wool, foamed polyurethane, polystyrene foam, etc., and pay attention to the arrangement of the material layer, it is best to use multi-layer material combination of the ceiling, so as to bring into play the characteristics of the various layers of materials. If the inner side of the composite structure is made of heavy materials of appropriate thickness or sandwiched with lightweight materials, its thermal stability can be further improved. The use of new energy-saving cold light source instead of incandescent lighting can also reduce the temperature rise in the warehouse.
2.3.3 Warehouse should have both airtight and ventilated performance
Warehouse ventilation, airtight performance is very important to the safety of grain storage, doors and windows open through the natural or mandatory ventilation can promote the exchange of grain pile gases, cooling and humidity, to prevent storage of grain heat and mold.
Reducing the warehouse temperature ventilation is the daily management of the warehouse, especially low-temperature grain storage management in an operation more frequent, hard, often need to be turned on in the middle of the night, the warehouse window automatic switch is the realization of the automatic operation of the warehouse temperature down a key step to slow down the rate of increase in grain temperatures, improve efficiency, reduce labor intensity is significant, and transformation of the investment is not very large, the efficacy of the more obvious, more than one of the existing grain warehouse The transformation is carried out.
To realize the automatic control of the grain pile ventilation, but also need to increase the air inlet automatic control device and fixed ventilator, now only a few grain storage of individual warehouses to achieve this function, and a limited number of times a year ventilation operation and investment costs are larger reasons to limit the popularization of the majority of grain storage.
The warehouse has good airtightness, for grain storage, air conditioning storage or fumigation insecticide are favorable, both can reduce the grain and outside air contact, to avoid the influence of external temperature and humidity and pest infection, so that the warehouse grain temperature, moisture to maintain a stable state; but also in the use of chemical fumigation, to maintain the effective concentration of the gas in the warehouse with the ratio, to get a good effect of insecticidal.
China's existing warehouse fumigation airtight requirements are: the warehouse door and window aperture sealing airtightness inspection, 500Pa pressure half-life of the bungalow warehouse is not less than 40s, shallow round warehouse is not less than 1min. This is the 1998 acceptance of the construction of new warehouses to determine the temporary standards, in the process of fumigation is also difficult to maintain the poisonous gas, the need to supplement the injection of drugs and insecticidal effect of the poor and other issues, should not be used as a basis for the development of new standards. As a basis for the development of new standards. With the improvement of the new warehouse design level, the new warehouse airtightness has been significantly improved, it is recommended to appropriately improve the airtightness standard of the warehouse, in the warehouse door and window aperture sealing, the half-life of the 500Pa pressure: cottage warehouse no less than 100 ~ 150s, shallow round warehouse no less than 2 ~ 3min. in the last two batches of 20 billion pounds of warehouse capacity in the construction of the warehouse capacity in the adoption of airtightness measures, most of the warehouses have met the standard, under the same conditions of drug dosage, one time to throw the drug, and the effect of insecticides, etc. should not be used as the basis for the development of new standards. Under the conditions of the dosage, a dosing to achieve better insecticidal effect, and the scientific use of phosphine, slowing down the emergence of drug resistance is favorable.
2.3.4 Warehouse should have anti-rodent, anti-finch facilities
In the grain storage period should be prevented from rodent and finch damage, rodents and finches not only consume a large amount of food, but also feces will contaminate the food. In order to prevent rats and finches, the requirements of the warehouse floor, warehouse walls, doors and windows must be strong and dense, do not allow holes. Warehouse must be set up to prevent bird window net (mesh ≤ 1cm) and anti-mouse door plate (height 0.6 ~ 0.9m) and so on. In order to improve the airtightness of the barn door, sometimes it is necessary to pre-buried plastic groove pipe in the inner 10cm of the door frame, so it is required to place the position of the anti-rodent plate is set in the inner 15cm of the barn door.
3 Safe storage of grain on the silo supporting equipment requirements
18 mechanized backbone of the silo application case proved that only good structural performance is not enough, but also need to be equipped with a perfect grain storage facilities, improve the grain depot inspection and the ability to deal with emergencies, in order to ensure that the storage of grain safety. The main grain storage facilities are:
3.1 Grain condition measurement and control system
Grain condition measurement and control system is the necessary facilities for long-term storage of grain heap, heap temperature, moisture and other parameters of the test value is the custodian of the deep grain layer to understand the trend of changes in the grain condition, grain analysis of an important basis and source of information and thus early discovery of the problem, to take the appropriate technical measures.
At present, most of the grain storage are equipped with grain condition measurement and control system, but its function, temperature and humidity parameter detection and data acquisition, grain condition analysis and control, compatibility and data **** enjoyment of different detection systems, component sealing and other aspects need to be perfected and improved. In recent years the research on grain storage and transportation of new technologies and equipment optimization and integration of demonstration projects, has developed a number of sets of grain pile intelligent ventilation control system, will further improve the function of grain condition control.
3.2 Ventilation and cooling system
Ventilation and cooling system is a necessary facility for all types of warehouses, it has a balanced grain temperature, effectively prevent the spread of moisture, grain heap heating and mold, and improve the performance of the grain storage and other roles, but also the ring fumigation, the application of the valley cold machine basis. In the selection or arrangement must pay attention to:
3.2.1 Duct selection and arrangement principles: in the selection of duct must be considered in the warehouse use, in and out of the warehouse operation form, ventilation pathway than the impact of other factors, in a warehouse (granary) can only be arranged in the form of a duct. Should be selected according to the requirements of uniform air supply, effective ventilation, the wind network process should be simple, symmetrical, air ducts out of the wind surface, ventilation resistance is small, construction or installation, operation and management are convenient air ducts. Duct perforated plate strength should be able to withstand the load of the grain or equipment, screen plate opening rate ≥ 25%.
3.2.2 Ventilation equipment should be safe and reliable, easy to operate, the fan pressure should be able to overcome the total resistance of the ventilation system, the fan air volume should meet the needs of different ventilation purposes such as ventilation, cooling, cooling, tempering and so on.
3.2.3 Reduction of warehouse temperature can be selected axial fan, each warehouse (granary) generally choose 2 to 4, it is recommended that the installation location as high as possible. Ventilation, open the north window, start the exhaust fan on the south wall or open the innermost window of the warehouse, start a single side of the wall of the exhaust fan, so that the cold air into the warehouse to maximize the ridge to take away the high temperature of the triangle.
3.2.4 Grain temperature reduction can use centrifugal fans or axial fans. Axial fan air volume, wind pressure is small, with low energy consumption, less water loss of grain and other characteristics, but the ventilation time is long, suitable for ventilation resistance of the system and the low temperature season longer grain storage; ventilation, open the air inlet ducts, close the barn doors and windows, open a number of axial fan to reduce the temperature of grain. Centrifugal fan air volume, wind pressure, with cooling fast, ventilation time is short, but higher energy consumption, more water loss of grain, suitable for ventilation resistance system and need to grab the time to ventilate the occasion; ventilation, open all the doors and windows of the barn, open the fan ventilation, exhaust can be discharged out of the barn smoothly.
It is recommended that the air inlet of the unilateral ventilation barn should be located in the north side of the barn, where the temperature is low, and it is favorable for the cooling of the grain pile, the cold operation of the grain, and the fumigation operation.
3.2.5 The structure of the air inlet should meet the requirements of easy opening and closing of the air inlet cover, convenient docking with the equipment, and good heat insulation and airtightness of the air inlet. Poor insulation airtight, open the trouble of the air inlet, can be used round air inlet or change into a double hinged door and butterfly dowel, buckle, revolving door or tie rod springs and other forms of fastening, plus the use of thick rubber strips and increase the inlet thermal insulation and other measures to solve.
3.3 Ring current fumigation system
Ring current fumigation system is a grain depot, especially the temperate zone south of the necessary facilities for grain storage, it can make the poisonous gas in the pile of grain rapid and uniform diffusion, reduce the labor intensity of the casting of drugs to reduce the exposure to the poisonous gas of time, and achieve a good insecticidal effect. In the application of attention:
3.3.1 In production, the fumigation pipeline is often combined with the ventilation system in the warehouse, designed to ventilate - fumigation **** with the system, will be used as a ventilator diffuser, so that the poisonous gas uniformly distributed in the grain pile, is conducive to improving fumigation effects, reduce the investment in fumigation equipment.
3.3.2 Phosphine is a flammable and explosive gas, in order to prevent phosphine combustion and explosion, the maximum linear velocity of the fan blade shall not be greater than 40m/s, phosphine combustion and explosion of the lower limit of the concentration of 26g/m3, therefore, into the fan of the poisonous gas concentration shall not exceed 1.7%.
3.3.3 In the FAO book "Ventilation of Subtropical Cereals", the recommended unit ventilation for ring-flow fumigation of q = 1.5m3/h?t, but for the ring-flow fumigation of phosphine, bungalow silo unit ventilation q ≤ 0.5m3/h?t, q ≤ 0.3m3/h?t tall silo.
3.3.4 To prevent phosphine gas Ignition and air resistance is too large, the wind speed in the annulus should generally be limited to 15m/s, the diameter of the main annulus should be greater than 100mm. 1998 in the construction of the new silo, the recommended main annulus inner diameter of φ125mm, the inner diameter of the annulus interface at the air inlet is φ65mm.
3.3.5 In the annulus fumigation, the current corresponding norms recommended or used in the production of The gas production method has cylinders of mixed gas method, phosphine warehouse outside the generator method and dynamic deliquescence method three, test and production application proved: insecticidal effect and fumigation concentration is related to the gas production method has nothing to do with the fumigation, but the fumigation cost is closely related to the gas production method. From the principle of "safety, economy, effectiveness and practicality", the "dynamic tidal decomposition" method is simple and safe to operate, and the cost is the lowest, so it has been widely popularized and applied.
3.4 Grain cooling system
Grain cooling system can be used for emergency treatment of hot grain, to prevent condensation, high-moisture grain storage, inhibition of insects and mold, maintain quality and other occasions. Its application is characterized by:
3.4.1 Direct cooling grain pile, grain cooling fast, bulk grain pile insulation is good, re-cooling interval is long, no need to build a special low-temperature warehouse.
3.4.2 Timely cooling, to stop the damp grain heat and mold, to extend the storage period, for dry ventilation and precipitation to win time.
3.4.3 Reasonable operation is the key point to determine the effectiveness of the valley cold, a note to choose a reasonable cooling and ventilation timing, try not to start in high temperature, high humidity; two to operate the equipment correctly, adjust the process parameters, so that the valley cooler in the economic state of operation, to solve the problem of cooling power consumption is too large.
3.4.4 Grain cooler is suitable for storage of slightly higher moisture or more sensitive to the temperature of the grain, such as the processing of high-quality rice for export, no low-temperature season or in the summer to deal with the heat of grain grain grain storage. Some people have done economic comparisons, the use of grain cooler grain pile cooling consumption of electricity is lower than the moisture loss caused by economic losses.
3.5 slow grading and anti-crushing device
When the grain quality is poor or high rate of waist bursting grain into the warehouse using machinery, especially the centralized into the grain silo type is taller, the grain drop is larger, it is very easy to form the automatic grading of the grain or serious crushing, the need to take to slow down the grading or anti-crushing measures.
The most effective measure to slow down the grading of impurities is to take the initiative to clean up and improve the quality of the grain into the warehouse, but the sieve in addition to the impurities will reduce the amount of grain, in the policy or the price can not make up for the loss of weight, some of the grain warehouse is reluctant to clean up. Passive measures are in the grain inlet to increase the fabricator, grain umbrella and other devices or take the center tube into the grain, multi-point grain, etc., but some devices can not achieve a better slow down the effect of grading.
The most effective link to reduce grain crushing should be to control the drying process parameters, that is, to choose the appropriate hot air temperature and precipitation rate, the wind temperature is too high, precipitation is too fast are prone to cause grain burst waist; followed by the control of grain in the elevation of the conveyor in the process of mechanical crushing; in the deep silo type of the inlet to increase the chute, telescopic tube or in the decompression pipe with deflector, etc., to slow down the fall of the grain into the silo speed, you can Control the crushing problem of the grain in the bin. According to the production and use of reflection, double funnel overflow, deflector to slow down the effect of broken better.
3.6 Grain silos should consider the mechanized operation of grain in and out
Grain depot storage of grain quantity, large volume, and sometimes need rapid turnover, in the design of the silo must be considered in and out of the grain, turning over the silo mechanization. This is particularly important for the port transit warehouse, processing plant raw materials warehouse, various uses of silos, large-capacity shallow round warehouse. But by the local economic development, traffic conditions, mode of transportation, labor prices and other factors.
In determining the grain in and out of the warehouse process, we must consider the warehouse structure and warehouse facilities, such as the size of the warehouse doors and windows and open the way, more than 6m grain pile of grain replenishment, the warehouse duct layout and in and out of the warehouse mechanical movement and other issues, and then determine the process of in and out of the warehouse, the selection of supporting machinery and equipment.
Bungalow warehouse low cost, but the grain in and out of the warehouse operation troublesome, long time, high cost, in developed countries belong to the proportion of silo type is not high, our country due to the limitations of national strength, the existing number of bungalow warehouse is more, in the future construction should also gradually reduce the number of bungalow warehouse. At present, China's bungalow silo into the grain is generally used mobile belt conveyor, there are also used in the warehouse machine or suction grain machine from the warehouse window for replenishment; out of the grain is generally used in the combination of bale picker and mobile conveyor, there is also the use of artificial way out of the grain.
Silos are more expensive, but the grain in and out of the warehouse quickly. Silo group is usually equipped with a working tower, tower set up lifting, cleaning, check catty, dust and other equipment, silo top and bottom are equipped with a horizontal conveyor, which completes the grain in and out of the warehouse operations.
Shallow round silo belongs to the transit - reserve warehouse type, its cost, in and out of the warehouse operation between the bungalow warehouse and silo, and the stability of the grain storage of large piles of grain is better than both. Shallow round silo into the grain by the elevator and the roof conveyor to complete; out of most of the grain rely on self-flow, by the bottom of the conveyor to take away, the remaining 20 to 30% of the grain by the loader, clearing machine, bale picker and suction grain machine and other ways to complete the unloading of the grain at this time the speed of the design of the equipment may not be able to reach the output and the time required.
In the current use, the shallow round silo reflects the most problems: shallow round silo as a reserve warehouse use, in and out of the grain process but according to the design of the transfer warehouse mode, machinery and equipment idle for a long time, high maintenance costs.
In short, the warehouse design should be combined with the grain storage technology and "four scattered" technology to ensure that the number of real food, good quality, to ensure that the country in urgent need of mobilization, use.