Dry-process porcelain enamelling of cast iron and like articles

Claim 1

IN A METHOD FOR COATING, WITHOUT HEATING DURING THE COATING OPERATION, A METAL ARTICLE WITH A SUBSTANTIALLY EVEN LAYER OF PORCELAIN ENAMEL OVER AN EXTENSIVE AREA OF THE SURFACE THEREOF WHEREIN SAID ARTICLE IS HEATED PRIOR TO THE COATING OPERATION TO A TEMPERATURE ABOVE THE MELTING POINT OF SAID ENAMEL AND ENAMEL POWDER IS DEPOSITED ON SAID SURFACE TO BE MELTED AND FORM SAID LAYER, THE STEP OF PREHEATING SAID ENAMEL POWDER IN A CONTAINER IN HEAT EXCHANGE RELATION WITH BUT SEPARATED FROM A SOURCE OF HEAT WHEREBY DIRECT CONTACT OF SAID ENAMEL WITH THE SOURCE OF HEAT IS PREVENTED PRIOR TO DEPOSITION ON THE SURFACE OF SAID ARTICLE THE ENAMEL BEING HEATED TO A TEMPERATURE BELOW THE SINTERING TEMPERATURE OIF SAID ENAMEL POWDER BUT SUFFICIENTLY HIGH TO PREVENT SUBSTANTIAL COOLING OF SAID ARTICLE UPON CONTACT WITH SAID ENAMEL POWDER.