| 摘要 |
1,201,018. Removing waste products in industrial processes. BALZERS PATENTUND BETEILIGUNGS A.G. 23 July, 1969 [5 Aug., 1968], No. 37049/69. Heading F4X. A filter 4 is arranged in the exhaust line of a vacuum furnace 1 together with means for alternatively by-passing the filter. The furnace shown, for melting metals, is evacuated by a pump 3, and contains a crucible 16 surrounded by an induction coil 15. Metal condensing in the vapour cloud above the melt at one stage in the process, forms a powder which is carried away with the waste gases through the exhaust outlet 2 and is intercepted by the filter 4. The filter is annular with a central passage 9 closable by a flap valve 6 actuated by a lever 5. During the powder producing stage of the process the passage 9 is closed by the valve 6 so that the powder-laden gases must pass through the filter 4 to reach the exhaust outlet 11. At the termination of this stage in the process, the valve 6 is opened so that the waste gases may pass directly through passage 9 and chamber 10 to the exhaust duet 11, thus by-passing the filter whereby the full suction capacity of the pumps is then utilized for maintaining the vacuum in the furnace chamber 1. 18 is a shut-off valve for the furnace. |
