Electromagnetic flowmeter and manufacture method of same

An apparatus comprising:

• a ceramic measuring tube through which fluid to be measured flows,
• a pair of electromagnetic coils disposed on an outer surface of said measuring tube at substantially a central longitudinal region thereof at diametrically opposite positions and generating a magnetic field in a direction perpendicular to a direction of flow of said fluid,
• a pair of measuring electrodes fixed to said outer surface of said measuring tube at substantially said central longitudinal region thereof at diametrically opposite positions and having electrode axes perpendicular to both said direction of flow of said fluid and said direction of said magnetic field, said measuring electrodes being fixed by a reaction product due to an interface reaction with said ceramic measuring tube under heating, and
• a pair of metallic shields fixed to said outer surface of said measuring tube in surrounding relation to said measuring electrodes by a reaction product due to an interface reaction with said ceramic measuring tube under heating,
• wherein said ceramic measuring tube is formed of at least one material selected from alumina and zirconia, and said measuring electrodes and said shields are formed of at least one material selected from an alloy containing molybdenum-manganese as a main constituent and an alloy containing tungsten-manganese as a main constituent.

An apparatus comprising:

• a ceramic measuring tube through which fluid to be measured flows,
• a pair of electromagnetic coils disposed on an outer surface of said measuring tube at substantially a central longitudinal region thereof at diametrically opposite positions and generating a magnetic field in a direction perpendicular to a direction of flow of said fluid,
• a pair of measuring electrodes fixed to said outer surface of said measuring tube at substantially said central longitudinal region thereof at diametrically opposite positions and having electrode axes perpendicular to both said direction of flow of said fluid and said direction of said magnetic field, said measuring electrodes being fixed by a reaction product due to an interface reaction with said ceramic measuring tube under heating, and
• a pair of metallic shields fixed to said outer surface of said measuring tube in surrounding relation to said measuring electrodes by a reaction product due to an interface reaction with said ceramic measuring tube under heating,
• wherein said ceramic measuring tube is formed of at least one material selected from alumina, zirconia, sialon, silicon nitride and silicon carbide, and said measuring electrodes and said shields are formed of at least one material selected from alloys containing titanium and an aluminum silicon base alloy;
• wherein a content of said alloy is in a range of 1% to 10% titanium;
• and
• wherein said alloy containing titanium contains silver-copper as a main constituent thereof.