Patent ID: 7959398

Claim:
An apparatus for rotary dumping of rail cars, comprising: a dumping facility having an interior and an exterior; a material receiving pit disposed within the interior of the dumping facility, the pit having a dumpside and a backside; a rotational frame disposed at least partially in the pit, the rotational frame configured to dump a load from a rail car during rotational motion of the rotational frame shifting along a path of travel between an upright position wherein the load is retainable in the rail car and a dumping position wherein the load clears the rail car; a backside airflow diverter disposed within the pit adjacent the backside of the pit, wherein the backside airflow diverter includes an upper surface; a backside hood for removing contaminated air from the backside of the pit; at least two baffles including a first baffle and a second baffle disposed on the rotational frame and supported by a baffle support, the at least two baffles each presenting a leading edge that is configured to contact the backside airflow diverter during at least a portion of the rotational motion, the first baffle coming into contact with the upper surface of the backside diverter prior to the second baffle as the rotational frame moves along the path of travel from the upright position to the dumping position, the leading edges of the two baffles being separated by a first distance along the upper surface of the backside diverter, the first baffle, the second baffle, the baffle support and the backside airflow diverter defining a first interbaffle space when the first baffle and the second baffle are in contact with the backside airflow diverter; the pit being subject to spike increases in pressure initiated by the load exiting the rail car and entering the pit, the spike increases in pressure traveling into the backside hood an attenuating distance from a primary hood intake before being attenuated, the attenuating distance being that distance from the primary hood intake at which the pressure within the backside hood is less than or equal to the pressure in the interbaffle space; and at least one secondary air intake positioned to pass through the upper surface of the backside diverter into the backside hood the air intake at a location at least the attenuating distance from the primary hood intake.