Silos grain

Finely divided combustible solids, if intimately mixed with air, can explode. Several disastrous explosions have occurred in grain silos. 

Test Station, China Lake, Caiif (Refs 3 vapor clouds were once considered a way-out technique. A cloud of volatile fuel, mixed with air, is discharged and then detonated on a target, with the same violent expin that characterized grain-silo dust explns or blast, when a propane tank truck blows up. This kind of expln can level a city block. 

Nitrogen dioxide is a reddish-brown gas that is heavier than air. It typically exists in the atmosphere as an equilibrium mixture with nitrogen tetroxide. As a relatively stable free radical, it can be found in ambient air at high concentrations near a source such as automobile exhaust or an electric arc. High concentrations are also found in grain silos. The chemical and physical properties of nitrogen dioxide are summarized in Table 8-1. 

It is sometimes possible to use judiciously placed drain holes to create a preferred flow path for subsequent grouting. Such procedures were used to control seepage into the underground portion of a grain silo, in a job done by Denver Grouting Services, Inc. 

Table 4.4 Analysis of grain taken from different levels in a grain silo...

Coal Mine, Munitions Factory Grain Silo, Hay Storage Facility... 

CLASS DIVISION 1 Combustible Dusts (Metals [Div. 1 only], Coal, Grain) Coal Mine, Munitions Factory Grain Silo, Hay Storage Facility... 

Roberts, A. W. 1988b. Some aspects of grain silo wall pressure research-influence of moisture content on loads generated and control of pressures in tall multi-outlet silos. Proceedings of the 13th International Powder and Bulk Solids Conference, Chicago. 

It is not necessary for a material to be a fluid for it to flow. Wheat, rice, corn, barley, and soybeans most certainly flow to and from grain silos. It is possible to analyze these products for moisture, protein, oil, and hardness while they are flowing at a surprisingly high rate of speed (2). 

Figure 3.25 (a) Flyash silo with buckle arrested by hopper impacting the ground (b) grain silo en route to... 

D. F. Themer, Failures of Reinforced Concrete Grain Silos, Transactions of the ASME Journal of Engineering for Industry, pp. 460 to 477, May 1969... 

It has been reported that thermal stresses may cause failures or even a collapse of grain silo structures [2]. Some results of earlier investigations on a steel storage silo in the USA have showed that a drop of ambient temperature over 4 °C per day accompanied by low external temperature (tg < -9°C) may cause a serious catastrophe [3]. Effects of temperature on a steel silo model [4] and also full-scale structures [5], [6] have been studied both in theory and experimentally. It has been stated that thermal actions on cylindrical reinforced concrete silo bin produce the following forces [7] ... 

Fig. 2. Temperature distribution across the wall thickness of grain silo in operation during heating and cooling phase of wall exposition to daily temperature variations (series 2).

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