| 摘要 |
The invention relates to an electromagnetic flow meter (1) comprising an outer tube (4), an inner tube (5) made of an insulating material and having flanges (6) which contact the ends of the outer tube (4), a magnetic coil system (7) situated between the internal faces of the outer and inner tube (4, 5) for generating a magnetic field which is perpendicular to the direction of flow of the fluid, as well as measuring electrodes (8) which traverse the inner tube (5). To cut production costs at least the inside of the inner tube (5) consists of polyethylene or high-density polyethylene instead of the polytetrafluoroethylene or chloroprene elastomer usually used to date. The invention also relates to a simple method of production of said flow meter, according to which the inner tube (5) is made from two end sections (19, 20) having flanges (6) and a cylindrical middle section (18) which is positioned between the end sections (19, 20). After the cylindrical section (18) has been inserted into the outer tube (4) one end (23) of one end section (20) is joined to one end (23) of said cylindrical section (18), which before being inserted into the outer tube (4) is provided with the magnetic coil system (7) and the measuring electrodes (8). The inner tube sections (18-20) are preferably joined by butt-welding with heat reflectors. |
