synonymGrain depot(Customary name of grain storage enterprises) Generally refers to grain warehouses
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A special building for storing grain.It mainly includes warehouses, freight yards (or sun yards), metering, transportation, stacking, cleaning, loading and unloading, ventilation, drying and other facilities, and is equipped with measuring, sampling, inspection and testing instruments.
Chinese name
Grain warehouse
Meaning
Special buildings for grain storage
Embryonic form
Bag shaped grain storage pit
Classification
Category 4
Bunker type
Housing and silos
Considerations
Grain type, storage capacity, construction cost, etc
A special building for storing grain.The bag shaped grain storage cellars during the Yangshao Culture period in China are the embryonic form of grain warehouses.By the Zhou Dynasty and the Spring and Autumn Warring States Period, more formal grain warehouses had appeared.It can be seen from the unearthed pottery barns and pottery kilns of the Eastern Han Dynasty that there were two kinds of grain warehouses prevailing in the Han Dynasty: round and square. "Round and square are called" kilns ", both of which are elevated, supported by wooden columns to prevent underground moisture and floods, and with windows to facilitate ventilation, reflecting a rather reasonable design idea more than a thousand years ago.The Hanjia Warehouse in the Sui and Tang Dynasties and the eight large warehouses in Beijing in the Ming Dynasty have further improved their facilities and are famous large grain warehouses in history.The grain warehouse in ancient Egypt was a cylindrical building with a round roof. Some of them had wooden platforms under them to protect the grain from ants and other pests. The platform base was paved with salt. The upper hole of the warehouse was the place where the grain was stored.Although the form and structure of grain warehouses have changed greatly in modern times, they are basically developed on the basis of the above ancient types.
The design of grain warehouse shall consider such factors as grain type, storage capacity (storage capacity) and construction cost, and the structure shall mainly meet the conditions required for safe storage of grain and technological operation of grain warehouse.The site selection and layout shall take into consideration such factors as abundant food sources, convenient transportation, sufficient energy, and high and cool terrain.
classification
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According to the tasks undertaken, national grain depots can be divided into the following four categories: ① grain storage depots.It is located in grain producing areas and mainly receives grain requisitioned from agricultural producers by the state.Generally, house type warehouses are mainly used, and the size of warehouses should be matched to meet the needs of receiving multiple varieties of grain. ②Transit grain depot.It is located at the transportation hub, mainly receiving the grain transported from the storage warehouse or port, and then transferring it to the supply warehouse or reserve warehouse after short-term storage.Mainly silo. ③Supply grain depot.Located in large and medium-sized cities, industrial and mining areas orcash cropThe grain consumption areas such as the district mainly receive the grain transferred from the receiving warehouse or the transit warehouse to be supplied to the grain processing plant or processed locally as finished grain or feed, and then supplied to the grain store for sale.Mainly silo. ④Reserve grain depot.Grain depots set up by the state to store necessary grain to cope with serious natural disasters and other special circumstances.Generally, it is better to have room type warehouse or underground warehouse with good moisture-proof, heat insulation, airtight or ventilation conditions.
Bunker type
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storehouse
Due to different structures, China's housing warehouses can be divided into: ① basic types of housing warehouses.Rectangular plane layout, double slope roof, mostly 20 meters long span single storey buildings, with large effective area and load storage capacity, each building has a capacity of 2500 tons.It can be packed or enclosed in bulk for easy cleaning, fumigation and disinfection, overturning grain piles and mechanized loading and unloading of grain. ②Arch house type warehouse.The double slope roof of the house type warehouse is replaced by an arched roof made of bricks. The arches are in three forms: circular arc, parabola and suspension line.Single curved arch refers to the arch made in one direction on the horizontal axis;The large-span brick arch roof, in addition to being arched in the horizontal axis, is also made of small arch type twin arches (or arch waves) in the longitudinal axis, called double arches.This kind of granary building saves wood, is very solid, and has good airtight conditions for fumigation, but it is difficult to construct. ③Thin shell warehouse.The shell structure is made of bricks to replace the small roof capacity of the house type warehouse, which can be used for the storage of small batches of grain.
Silo
It is a three-dimensional vertical deep silo, usually composed of three parts: working tower, silo group and receiving device, with large capacity, and most of them have high mechanization and automation devices.The working tower is generally a multi-storey buildingreinforced concreteOr the mixed structure is built, which is the operation center of the silo, with various equipment installed inside, such as conveying, weighing, cleaning, dust collection, diversion, etc.The grain is sent to each bin by conveyor after various processing steps.The silo is composed of three parts: the top layer, the bottom layer and the silo body.The top layer of the cylinder is used to place the bin top conveyor for grain feeding;The bottom layer of the barrel is used to arrange the bin bottom conveyor and grain chute for grain discharging;The silo body is used for grain storage.A certain number of silos form a silo group. Most of their combinations are determinant, with rows in the longitudinal direction and columns in the transverse direction. Usually, the number of rows is 2-4, and the number of columns is 4-8. The space between four adjacent silos is called star silo, which can also store grain.The receiving device mainly refers to the railway receiving device, highway receiving device and wharf receiving device connected to the station or wharf, and is composed of mechanical shovel, grain suction machine, belt conveyor and car tilt device.This type of bin has the advantages of good airtightness, high mechanization and automation, large capacity and less land occupation, and has been widely used in the world (seesilo)。
In addition, the main load-bearing structures of the underground silo, such as the silo wall and roof, are buried below the ground.Due to the good underground heat insulation and airtight conditions, it is conducive to the low temperature and dry storage of grain. Some of the perennial temperatures are below 20 ℃, and the grain is basically free from pests and microorganisms, which can maintain the grain quality for a long time.The underground warehouse also has the advantages of convenient construction and low cost.The earth silo is a simple silo with mud grass structure, which is suitable for areas with less rainfall.
Warehouse design
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The general requirements are: ② firm and durable.The warehouse shall be able to bear the lateral pressure of grain on the wall and the total pressure on the bottom of the warehouse to prevent cracking and sinking.Generally, masonry structure or reinforced concrete structure can be used, and steel plate silo can also be made of steel plate. ②moisture-proof.Warehouse wall, wall root and floor are usually the parts that are most likely to cause moisture and mildew of grain.Therefore, the warehouse should be located at a place with low groundwater level, dry foundation and smooth drainage around. The floor in the warehouse is generally higher than that outside the warehouse.Damp proof materials such as asphalt, asphalt felt or waterproof rubber shall be laid on the warehouse wall, floor and roof. ③Insulation.The level of the house type warehouse is the main way for external heat to enter the warehouse.Therefore, it is necessary to add roof thermal insulation layer or ceiling to increase thermal insulation performance.For manually refrigerated warehousesThermal insulation materialThermal resistance, thermal storage performance, etc.Common thermal insulation materials include rice husk, vermiculiteExpanded perlite、Polystyrene foamEtc. ④Ventilation.During grain storage, ventilation is sometimes required to cool down and dissipate moisture, and sealing is sometimes required to reduce the impact of external temperature and humidity on the grain in the warehouse.The ventilation problem is usually solved by setting windows and timely opening and closing in general room type warehouses.For grain stacks that need strong ventilation, there are specially designed ventilation warehouses and ventilation devices, such as radial ventilation devices, trench ventilation devices, etc. ⑤Air tight.When using low oxygen, high nitrogen or highcarbon dioxideDuring controlled atmosphere storage, the warehouse shall have sufficient air tightness to maintain the effective concentration and ratio of gas in the warehouse.The airtight warehouse shall be sprayed with proper sealant and sealing process.Common sealants are:Silicone rubberAsphalt rubber sealant,PolychloropreneRubber, styrene acrylic emulsion sealantPolyurethane foam, soft PVC copolymer glue coating, etc. ⑥Prevent rat and bird.For example, a bird proof window net and a rat proof door panel are provided.In addition, in order to meet the requirements of granary operation, there should also be auxiliary buildings such as working tower, drying tower or drying yard, and receiving device connecting the dock or station.
