an apparatus for melting particulate polymeric material includes a melting grid and a molten polymer reservoir beneath the grid . the apparatus has a lateral cross - sectional contour defined by walls . further included is a distribution device having upper and lower surfaces and adapted to the contour of the molten polymer reservoir , which device is disposed in the molten polymer reservoir in proximity to the grid . the device has an internal reservoir formed between the upper and lower surfaces ; a perimetrical surface joining the upper and lower surfaces and providing the device with height ; at least two fluid distribution pores , each having one end in communication with the internal reservoir and another end disposed in the circumferential surface ; and an injection tube providing fluid flow communication between the internal reservoir and an external supply of fluid .