The disclosure relates to a machine for thermal treatment of bulk material, comprising: a stationary furnace which presents a support structure, and a plurality of pallet cars traveling through the furnace, said plurality of pallet cars together defining, at a lateral side thereof, a common engagement surface which extends through the furnace, wherein a gap is defined between the support structure of the furnace and the common engagement surface, said gap having a gap length, the machine further comprising: a sealing system comprising a series of leaf members which are partially overlapping, wherein each leaf member of the series of leaf members is connected to the support structure at a first end thereof, and self-biased into engagement with the engagement surface at a second, opposite, end thereof such that the series of leaf members, together, cover the gap over at least part of the gap length.