An apparatus (2) for the impregnation of metal castings including an impregnation chamber (11) having an open end; a movable assembly (2) comprising a cover (20) for closing the open end of the impregnation chamber, a casting carrier (21), carrier transport means (22) for raising and lowering the casting carrier relative to the cover, and carrier rotating means (23); and transport means (24) for raising and lowering the movable assembly relative to the open end of the impregnation chamber. The impregnation chamber is partially filled with liquid sealant (30). The apparatus is operated to position the carrier in the impregnation chamber above the liquid sealant therein and develop a vacuum in the chamber, submerge the carrier (and castings therein) in the sealant, and then raise the carrier above the sealant level and rotate carrier to spin-off excess liquid sealant; the movable assembly is thereafter raised to unload impregnated castings.

In a conventional method of impregnating die-cast articles, the sealing property is not excellent due to air being dragged into the sealant. In the present invention, the dragging of air into the sealant is prevented by adjusting the pressure of the sealant storage vessel and the pressure of the impregnation vessel to substantially the same level and then flowing the sealant from the sealant storage vessel into the impregnation vessel. After impregnation, the sealant reenters the sealant storage vessel, and pressure is applied to the die-cast articles so as to remove excessive sealant from them.

A pressure vessel for use in impregnating porous articles comprising a support member for the articles, slidable between an upper position for degassing the articles and a lower position for impregnating the articles, a release mechanism operable from outside the pressure vessel to permit the support member to descend from the upper position to the lower position under gravity, and damping means at least partially within the pressure vessel for controlling descent of the support member.

An infrared burner with an extremely low pressure drop is described. The burner comprises a corrosion resistant mesh screen having a thick porous coating of ceramic fibers deposited thereon. In addition to a low pressure drop the burner has structural integrity and ability to generate energy at a high rate. The burner is produced by admixing ceramic fibers with a polymeric material which burns off upon heating.

An impregnating carbonizing process and apparatus which permit reduction in cost of consumable goods and can operate at a reduced cost and a heating and vacuum impregnating operation which requires a very long period of time can be performed on the outside of an expensive high pressure vessel to accomplish rapid carbonization and baking. The process comprises of inserting a porous shaped body of carbon and a block of impregnant into a specimen case, discharging gas from within the specimen case, heating the impregnant into a molten condition under a reduced pressure, inserting the specimen case into a high pressure vessel, admitting high pressure gas into the high pressure vessel and also into the specimen case so as to penetrate the impregnant into the shaped body of carbon, heating the shaped body to a high temperature, and discharging the high pressure gas to lower the pressure within the specimen case at a controlled rate in response to a pressure within the high pressure vessel to carbonize the impregnant. The apparatus is constructed to suitably carry out the process.