consists of identical upper and lower chamber portions 18 and 20 respectively the portions 18 and 20 are vertically related with the portion 18 being directly above the portion 20 wherein a vertical spacing 22 exists between the upper and lower chamber portions within the spacing 22 an endless conveyor 24 is located upon which the heated part to be cooled indicated at 26 is supported the conveyor 24 is supported upon rollers 28 fig2 and the conveyor is driven by a conventional motor drive system not shown the conveyor 24 is air pervious as the cooling air from the lower chamber portion 20 must pass therethrough and the conveyor 24 may include a plurality of openings or may be formed of an open flexible material such as chain link or the like both the upper chamber portion 18 and the lower chamber portion 20 are horizontally divided by plates 30 fig3 wherein approximately one half of the volume of a chamber portion exists on each side of the associated plate 30 with reference to fig3 the chamber portions located the greatest distance from the conveyor 24 constitute air supply manifolds 32 while the portion of the chambers closest to the conveyor 24 constitute air exhaust manifolds 34 the air supply conduits 36 include a variable speed fan insert 38 fig3 and pressurized air from the air supply system 14 passes through conduit branches 40 and volume control dampers 42 through ports 44.