Dust explosions occur when high concentrations of fine combustible particles in the atmosphere are ignited within an enclosed space. A wide variety of materials can generate a dust explosion including corn, 锯末, 煤炭, 药物, 染料, 金属, 塑料和橡胶. 即使是通常不被认为是可燃的材料, 比如阿司匹林或糖, 燃烧时是否会产生爆炸. Grain dust is an especially combustible hazard and can result in very violent and destructive explosions within grain elevators.
在美国, “谷物升降机”收到, 商店, 加工和运输各种农产品. Grain elevator facilities specifically employ bucket elevators to transport grains from the bottom of the elevator to a distributor at the top. 使用极大的滑轮, the vertical conveyor belt vigorously moves thousands of cubic feet of grain per hour during normal operation resulting in the formation of a combustible dust cloud inside the bucket elevator.
谷物提升机的轴承为滑轮时可能发生爆炸, 哪些通常安装在电梯外壳的外面, seize up and overheat causing the combustible dust inside the elevator to ignite. This can lead to a catastrophic explosion and significant property damage, injury, or loss of life.
尽管NFPA 61中概述的要求: Standard for the Prevention of Fires and Dust Explosions in Agricultural and Food Processing Facilities 能帮助减轻或防止谷物粉尘爆炸吗, 皇家88账户注册些保障措施通常不存在于农业设施中. 而不是, facility operators – whether they know it or not – rely on adequate lubrication to prevent the ignition of dusts from overheated bearings. 问题是, 当轴承没有正确润滑时, 粮食升降机可能发生火灾和爆炸.
A 粉尘危害分析 performed by Jensen Hughes consultants is a systematic review of potential fire, 闪火, or explosive grain dust hazards and the prevention plan to mitigate the risk. Part of the DHA consists of testing the dust using our one-cubic meter explosion chamber in order to quantify the explosibility of the dust. 该实验室还设有一个20-L Siwek爆炸室, capable of characterizing dust explosibility parameters such as explosion severity and ignition sensitivity.
例如, a forensic investigation of a 2019 grain elevator dust explosion in Illinois revealed improper lubrication as the cause of the explosion. The subject grain elevator had been built and installed for 10 years prior to the accident and had been operating without any incidents. The facility had well-documented records of grease being applied to the bearings at appropriate intervals. 事故发生前几个月, 然而, the facility switched greases for all its bearings because their supplier was no longer carrying the grease they had been using.
Laboratory testing as part of the forensic investigation showed that the base oil viscosity of the manufacturer-recommended grease was higher than that of the grease being used by a factor of four. 因此, the lubricant film between metal surfaces was much thinner than intended by the manufacturer which led to metal-to-metal contact inside the bearing. This, in turn, resulted in a bearing fire culminating in a grain dust explosion in the elevator. 幸运的是, 没有人在爆炸中受伤, 但该设施造成了重大的业务中断成本.
当设备更换润滑脂材料时, there is always the potential for incompatibility between the manufacturer-recommended grease and the new greasing agent. Many people in the industry rely on compatibility charts found in trade magazines and web pages to make important maintenance decisions. 然而, contradictions exist among some of these charts and very few provide the origin of the data or research used to establish the compatibility relationships.
The hazards associated with the change in grease could have been detected had the facility implemented a Management of Change (MOC) approach. Under the Occupational Safety and Health Administration’s (OSHA's) 过程安全 Management (PSM) standard, 实际上，某些皇家88娱乐需要执行MOC, but the methodology is applicable and beneficial to all facilities to minimize risks when implementing changes in process chemicals, 技术, 设备, 和程序.
This incident ultimately reinforces the importance of properly lubricating grain elevator bearings and verifying that the grease being used meets requirements set forth by bearing manufacturers to prevent grain dust elevator explosions. Even though the Illinois facility was greasing the bearings at an adequate frequency and had the maintenance records to prove it, operators were unaware of the hazards presented when the facility changed the greasing agent. 市面上有各种各样的润滑脂, the issue of grease compatibility is not straightforward and should be 经实验室测试确定.