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Silo is required for long-term storage of crops. But silos are dangerous, and every year people are killed or injured in the process of filling and maintaining them. The equipment used is dangerous, and workers may fall from a tower silo ladder or work platform. Several fires have occurred over the years.
Dangers of the loading process
Filling a silo requires two tractors parked very close to each other, both running at full power and with live PTO shafts, one powering the silo blower and the other powering a forage wagon that unloads freshly cut forage into the blower. In this highly dangerous environment of spinning shafts and high-speed conveyors, the farmer must constantly rotate to check material flow and adjust speed, and turn all equipment on and off between loads.
In preparation for filling a silo, the unloader must be tilted upwards and any remaining forage at the base that the unloader could not pick up must be removed from the floor of the silo. This job requires the farmer to work directly under a machine weighing several tons, suspended fifty feet or more overhead from a short steel wire. If the unloader falls, the farmer can die instantly.
Dangers of the unloading process
Unloading also poses special hazards, due to the requirement that the farmer regularly climb into the silo to close an upper door and open a lower door, moving the unloader chute from room to room in the process. Fermentation of silage produces methane gas which over time displaces oxygen at the top of the silo. A farmer walking directly into a silo without any other warning could be suffocated by methane, pass out, and silently suffocate before anyone else knows what happened. If it is necessary to ventilate the silo with fresh air, a silo blower connected to the silo needs to be left on at all times, or a dedicated electric fan system to blow fresh air into the silo before anyone tries to enter. Once it is plugged into the unloader mechanism, the farmer must climb into the silo and stand directly on the unloader, reaching the blower spout to dig up the soft silage. After clearing a plug, the forage forks should be spread out in an even layer around the unloader so that the unloader does not immediately dig into the pile and plug again. During all these processes the farmer stands on or near a machine
Hats can easily kill them in seconds if they start accidentally. This can happen if someone in the barn inadvertently starts the unloading process while someone is in the silo working on the unloader.
Often, when unloading grain from the bottom of a silo or other opening, another worker will stand on top of the grain to ensure an even flow of grain from the silo "walking it down", sometimes unstable pockets of grain fall under the worker while walking; This is called grain entrapment because the worker can become completely submerged in the grain within seconds. Entrapment can also occur while the grain is moving or when workers clear large clumps of grain stuck to the sides of silos. This often results in death by suffocation.
Dangers of dry ingredients/bins
There have also been many incidents of bursting of ducts and buildings. If the indoor air becomes laden with fine-grained particles, such as grain dust, a spark can cause a dust explosion strong enough to blow apart concrete silos and surrounding buildings, usually setting the surrounding grain and buildings on fire. Sparks are often caused by rubbing against (metal) metal conduits; or due to static electricity produced by dust along ducts when over-dried.
The two main problems that will require silo cleaning in bins are 'bridging' and 'rat-holding'. Bridging occurs when the material passes over the unloading process at the base of the bin and blocks the flow of stored material into the unloading system by gravity. Rat-holing occurs when the material begins to stick to the sides of the bin. This will reduce the operating capacity of a bin as well as lead to cross-contamination of new material with old material. There are many ways to clean a bin, and many of them carry their own risks. However, acoustic cleaners became available in the early 1990s. They are non-invasive, have minimal risk, and can offer a very cost-effective way to keep a small particle bin clean.
- SZK is based on online information.
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