Abstract: A process is disclosed for the production of metal sheets enamelled with two layers, wherein the sheet is coated, before shaping, with a polymer suspension. The sheet is then dried and shaped, and optionally is coated with an enamel frit. The sheet is then fired at a temperature of 560 to 850 degrees C. The binder in the polymer suspension is preferably a material which burns completely at melting and stoving temperature.

Abstract: The measuring tube is for an electromagnetic flow meter and has a tube member made of a non-magnetic material that is provided with opposite through passages that have electrodes extended therethrough. An insulating lining of an enamel priming layer coats the inner surface of the tube member and fills the gaps between the electrodes and the tube member surfaces defining the through passages, the lining also including an covering enamel layer covering the priming layer surface that is within the tube member interior. The end faces of the electrodes that are in the tube member interior have the enamel material cleared therefrom. The priming layer may be formed by filling the tube member with a priming enamel slip, pouring out the slip material, cleaning the electrode end surfaces that are within the tube member interior and then heating to melt the slip material and then cooling. The covering layer may be formed by the same steps.