The Model WSM-04 is a centrifugal dryer intended for use in Class 1, Division 1, Groups C and D hazardous (classified) locations. Its function is to remove liquid (primarily lubricants) from oil well drill cuttings. The lubricant-laden cuttings are fed into a charging hopper at the top of the unit and flow into a space between a cone and a conical basket with screen. The cone and screen rotate in the same direction at slightly different speeds. The centrifugal force moves the liquid through the screen and is aided by the speed differential and a set of flights on the cone. The liquid flows out through the screen and into a trough or launder area in the main base where discharge ports are located. The solids are moved down by gravity through discharge areas inboard of the liquids trough. The main drive motor is a 75hp vertical explosion-proof motor. A belt drive is used to transmit power to the driven sheave mounted to an external shaft of the gear case assembly. An internal shaft is driven through a series of gears. The external shaft drives the basket/screen assembly. The internal shaft drives the cone assembly. The gear set provides the speed differential between the two shafts. A hollow pinion shaft extends out of the bottom of the gear case assembly and is coupled to a fixed plate (input hub) at the base of the unit. The coupling used is a T.B. Woods Sure-Flex coupling and consists of two metal coupling flanges and a two-piece toothed rubber coupling which is held together by a metal ring. The pinion shaft does not normally rotate. A planetary gear set revolves around the pinion shaft. If foreign material enters the hopper and jams the basket/screen assembly or the cone, this will cause the pinion and top coupling flange to rotate. The teeth of the rubber coupling give way since the bottom coupling flange is bolted to the plate at the base of the unit. Once the coupling teeth shear, the jammed rotating assembly can spin freely. Since the speed differential between the basket/screen assembly and the cone is eliminated, the likelihood of damage to the gear case components is minimized. The circulating oiling system is a closed system. Gear oil is fed to the gear case assembly through the center of the pinion shaft. The gear case is oil-filled, such that all bearings and gears are immersed in lubricant. The system includes a 1/2hp explosionproof motor that drives the oil pump, a filter assembly, vacuum and pressure gauges, check valves and an explosion-proof pressure switch along with an explosion-proof flowswitch. To eliminate the potential for any percussion sparking in the space between the basket/screen and the cone, in the event of a jam in the dryer, the center rubber components of the Woods coupling fail in order to protect the gear drive. The inclusion of the Woods coupling, is to prevent thermal ignition or ignition due to percussion sparking. The drive belts accumulation of electrostatic charges, which is inherent in a friction driven application, is addressed by using belts that have adequate electrical conductivity. The belts specified are Dayco Corp. Gold Label Cog-Band belts or equivalent there to. These design features are taken specifically to meet the requirements for use in Class 1, Division 1, Groups C and D hazardous locations.