| 摘要 |
A system and device for introducing gas into molten metal comprises: 1) a pump having a pump chamber and a discharge, 2) a gas-release device for releasing gas into the discharge, and 3) a flow-directing device to substantially reduce or eliminate the low-pressure zone behind the gas-release device. The pump creates a stream of molten metal through the discharge. The gas-release device, which is preferably a graphite tube, has an end extending into the discharge. Gas is introduced through the gas-release device into the discharge where it escapes into the molten metal stream passing therethrough. The flow-directing device is positioned behind the end of the gas-release device to eliminate the low pressure zone that normally forms there. During operation, the molten metal is diverted around the sides and bottom of the flow-directing device and the gas is dispersed within the molten metal, rather than being trapped in a low-pressure zone. The system may also comprise a metal-transfer device, such as a conduit extending from the pump outlet, for containing the molten metal stream. In that case, if the gas-release device releases gas into the metal-transfer device, the flow-blocking device is positioned within the metal-transfer device downstream of the gas-release device.
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