Unitary electromagnetic flowmeter with sealed coils

An electromagnetic flowmeter unit interposable between the flanged ends of upstream and downstream pipes in a line carrying a fluid whose flow rate is to be measured, the flanged ends being bridged by bolts which encage the unit and subject it to a compressive force to effect a fluid seal, said unit comprising:

• A a non-magnetic metal spool having end flanges to provide a flow conduit having a longitudinal flow axis, said spool having a strength sufficient to withstand the pressure of the fluid and said compressive force;
• B an insulating inner liner for said spool;
• C a cylindrical housing formed of ferromagnetic material surrounding said spool and concentric therewith, said housing having end plates mating with the flanges of the spool to create an annular inner chamber between the spool and the housing;
• D a pair of thin coils in said chamber adjacent the inner surface of the housing at diametrically opposed positions with respect to said flow conduit, said coils surrounding a coil axis intersecting said flow axis at right angles thereto;
• and
• E a pair of electrodes mounted on said spool at diametrically-opposed positions along an electrode axis which is perpendicular both to the flow axis and the coil axis, said inner chamber being filled with a potting compound to seal said coils and said electrodes therein.