| 摘要 |
1,044,415. Inking apparatus. BROOKHIRST IGRANIC Ltd. March 16, 1965 [March 30, 1964], No. 11102/65. Heading B6C. [Also in Division H2] In an electrostatic arrangement for suppressing ink mist in a printing press and comprising a high voltage conductor adjacent an earthed ink transferring roller of the press, means respond to the occurrence of an arc between the conductor and roller to interrupt the power supply to the conductor to extinguish the arc and, after a timed interval, to restore the power supply. In Fig. 1 the conductors 6 are supplied by a voltage regulating transformer 1PT through a voltage doubling rectifier circuit 15 ...20 when the contacts 1TR1 of a time relay 1TR close with a time delay. In the event of arcing between conductors 6 and earthed rollers, indicated at 7, the current flowing in the secondary circuit of the transformer is sufficient for a control relay 1CR to open its contacts 1CR1. The relay 1TR is de-energized and opens its contacts 1TR1 without delay to interrupt the supply. The relay 1CR then releases and relay 1TR recloses with a time delay to restore the supply. In a modification, Figs. 2 and 3 (not shown), the control relay is connected to the saturating winding 12 of the transformer and effects the interruption of the supply when the voltage across the winding falls due to excessive current in the secondary winding 11 of the transformer. Fig. 5 (not shown) illustrates an arrangement having a stepping switch to finally interrupt the supply after a predetermined number of arcs have occurred. In a further arrangement, Fig. 6 (not shown), the power supply is finally interrupted if arcs occur at a predetermined rate, an increment of charging current being received by a capacitor each time an arc occurs and the supply is interrupted. The capacitor can discharge slowly through a resistor, but if the rate of arc occurrence is high then the capacitor is sufficiently charged to cause a Zener diode or neon glow tube to breakdown so that a relay is operated to prevent automatic restoration of the supply.
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