| 摘要 |
<p>1,069,868. Removing waste products in industrial processes. LANDBOUWWERKTUIGEN-EN MACHINEFABRIEK H. VISSERS N.V. Dec. 8, 1965 [Jan. 14, 1965], No. 62046/65. Heading F4X. Vapours generated by an electric welding operation are withdrawn upwardly through an exhaust flue 3 by a fan 6, and a valve 4 in the exhaust flue is opened automatically after a predetermined time when the welding current is switched on and closed after a predetermined time when the welding current is switched off. The valve shown is operated by an electromagnet 5 energized by a transformer coil 9 arranged around the cable 7 which feeds current to the welding electrodes; and the electric circuit includes a relay 10 adapted to delay opening or closing of the valve until a predetermined time has elapsed. The arrangement avoids repeated operation of the valve during an intermittent welding operation, e.g. when forming a chain of welds. A single exhaust flue may serve a plurality of welding units (Fig. 2) and may include a further valve (12) loaded by a weight and adapted to open to admit atmospheric air if the pressure in the exhaust flue falls to a predetermined value.</p> |
