| 摘要 |
1,042,970. Controlling soaking pit furnaces; gas burners. LOFTUS ENGINEERING CORPORATION. Dec. 9, 1963 [March 28, 1963], No. 48546/63. Headings F4B and F4T. A high velocity gas burner 4 for heating a soaking pit 2 comprises a gas duct 15, two annular concentric air chambers 10, 11 discharging air through orifices 12, 13 in a refractory baffle 6, and a flap valve 40 controlling the flow of air from a duct 7 into the air chambers 10, 11. In one position of the flap valve 40 the chamber 10 only is supplied with air, in another position the other chamber 11 only is supplied and in a third position both chambers are supplied. The orifices 12, 13 are arranged in two circles concentric with the gas duct 15 but in a modification, Figs. 4, 5 (not shown), the orifices are arranged in a single circle, there being two orifices 12a between each two orifices 13a. The air is supplied by a blower 20 and is heated by a recuperator comprising two sets of steel tubes 18 positioned in a flue 19 of the soaking pit. The gas is supplied by a line 14 and is controlled by a valve 30 actuated by a motor 26 operated by an amplifier and temperature indicator 25 responsive to a thermocouple 24 disposed in the soaking pit. The air flow is automatically controlled in accordance with the gas flow by a butterfly valve 36 actuated by a motor 39 connected pneumatically or hydraulically to a gas-air ratio controller 35 responsive to the pressures on the upstream and downstream sides of orifice plates 31, 32 in the gas and air supply lines. The flap valve 40 controlling the flow of air into the air chambers 10, 11 of the burner is actuated by a motor 45 electrically energized by a gas flow recorder 47 receiving through tubes 33, 48 the differential pressure at the orifice plate 31 in the gas line. At the start of an ingot-soaking process the air and gas are delivered at maximum capacity and the flap valve 40 directs the air into both chambers 10, 11. At a preset temperature of the indicator 25 the gas valve 30 gradually closes and the temperature of the pit decreases so that consequently the gas valve again opens. This cycle is repeated. When the gas flow is less than two-thirds of the maximum rate the recorder 47 operates the flap valve to stop the flow to the inner chamber 11. When the ingots reach the desired temperature the flap valve 40 is thrown through 180 degrees to open the flow of air to the inner chamber 11 and stop the flow to the outer chamber 10. |
