Gas purging plug, gas purging system, method for characterization of a gas purging plug and method for purging a metal melt

Gas purging system comprising a gas purging plug (10) for metallurgic applications and a gas supply pipe (30) connected to the gas purging plug (10), the gas purging plug (10) comprising:

• a.) a ceramic refractory body (10k) with a first end (10u) and a second end (10o);
• b.) the second end (10o) is in a mounted position of the gas purging plug that is in contact with a metal melt;
• c.) the first end (10u) is at least partially covered with a metal cover (12.1), the metal cover (12.1) comprises an opening (16) to which optionally a gas supply adapter (20) is connected;
• d.) the gas purging plug (10) is designed in such a way, that a purging gas which is supplied via the gas supply pipe (30) to the opening (16) flows through the body (10k) and exits the body (10k) at the second end (10o);
• e.) and wherein at least one electronic sensor (70, 70.1, 70.2, 70.3, 70.4) is in direct contact with the gas purging plug (10), to detect an oscillation waveform of a mechanical vibration (81), whereas the electronic sensor (70, 70.1, 70.2, 70.3, 70.4) is an acceleration sensor;
• the gas purging system further comprises:
• f.) a data processing unit (80) for acquiring the oscillation waveform of a mechanical vibration (81) detected by the electronic sensor (70, 70.1, 70.2, 70.3, 70.4) of the gas purging plug (10) and for calculating a bubble index-signal (83) from the oscillation waveform of a mechanical vibration (81) detected;
• g.) a control unit (100);
• wherein the control unit (100) is configured to:
• display the bubble index-signal (83);
• and/or
• vary the volume flow (102) through the gas supply pipe (30) depending on the bubble index signal (83);
• and/or
• generate a warning signal (101) when the bubble index signal (83) lies outside a defined range.

Method for characterization of a gas purging plug (10), comprising the following steps:

• Setting an actual volume flow (300) of a gas through the purging plug (10);
• Acquiring an oscillation waveform of a mechanical vibration (81) at the actual volume flow (102) by at least one electronic sensor (70, 70.1, 70.2, 70.3, 70.4) in direct contact with the gas purging plug (10), whereas the electronic sensor (70, 70.1, 70.2, 70.3, 70.4) is a piezoelectric acceleration sensor;
• Calculating at least one bubble index component (301) from the acquired oscillation waveform of a mechanical vibration (81) at the actual volume flow (102);
• Storing at least one bubble index component (302).

Method for purging a metal melt (41) in a metallurgical vessel (40) with a gas, comprising the steps of:

• Setting an actual volume flow (401) of a gas through a purging plug (10) to a pre-determined value of an initial volume flow (102);
• Acquiring an oscillation waveform of a mechanical vibration (81) at the actual volume flow (102) by at least one electronic sensor (70, 70.1, 70.2, 70.3, 70.4) in direct contact with the gas purging plug (10), whereas the electronic sensor (70, 70.1, 70.2, 70.3, 70.4) is an acceleration sensor;
• and:
• Varying the volume flow (404) through the gas supply pipe (30) depending on the acquired oscillation waveform of the mechanical vibration (81);
• and/or
• Generating a warning signal (403) depending on the acquired oscillation waveform of the mechanical vibration (81).