Abstract: A reciprocating assembly for applying vapor steam to the surface of a multi-width conveyor belt, having a frame to support the belt, to clean and sanitize the conveyor belt, includes, a housing having two ends, with the housing enclosing an endless chain member positioned within the housing and powered by a motor member, with the chain member having a cam member extending outwardly from the endless chain, a reciprocating block member supports a nozzle, with the block member having a cam guide notch structurally arranged to be engaged by the cam member extending from the endless chain member. The housing ends are engageable with vertical housing supports to mount the assembly to the conveyor belt frame to predeterminely control the reciprocating movement of the nozzle between the edges of the conveyor belt.