| 摘要 |
Preheated liquid material is pumped into inlet (32) of electroheating cell (34) and, in turn, passes through an inlet end electrode body (98), a central electrode body (110), and an outlet end electrode body (118). The inlet end and central electrode bodies (98), (110) are separated by a conduit (62), and the central and outlet end electrode bodies (110), (118) are separated by a second conduit (84). The cross sectional area of the bore of the electroheating cell (34) varies along its length, being significantly greater in the vicinity of the electrode bodies than in the conduits (62, 84) . Conical-shaped passageways between the electro bodies (98, 110, 118) and the conduit (62, 84) are provided where there is a change in bore cross-section. The inlet and outlet end electrode bodies (98), (118) are earthed, whereas the central electrode body (110) is connected to a mains frequency alternating potential source (148). In use, liquid material flowing between the electrode bodies (98, 110, 118) in the electroheating cell (34) is heated by currents generated by the potential difference imposed by source (148). The current densities attained in the conduits (62, 84) are substantially higher than those in the passageways adjacent the electrode bodies (98, 110, 118) because the cross-sectional area of each conduit (62, 84) is smaller than the cross-sectional area of each of the electrode surfaces. The current densities are controlled so that material flowing through the electroheating cell is heated more while passing through the conduits than when in the vicinity of the electrode surfaces. <IMAGE> |
