level of liquid steel inside mould during casting time is continuously measured, be it open or close casting. depending upon the type of casting, measured level in mould drives the strand speed (in open casting) or, opens/closes the tundish slidegate (in closed casting) so as to meet the casting speed given to the strand withdrawal motors.
this following pics show the physical elements necessary to measure mould level in a continuous casting machine.
in the first pic, at the center is the mould, at the bottom we have the detector, and at the top lies the radioactive source.
the picture above shows the mould of square billet sized 150mm . i created this in visual studio to understand start of casting steps, as the mould gets filled, dummybar withdrawal, filling up of mould to reach the target of around 150mm in detected range, the auto withdrawal start, auto regulation of level to meet the target level.
the pic below shows the schematic mould setup in CCMs; the mould water flow is also shown along with AMLC detection details.
it is a Co-60 radiation source, which normally has a good working life of 6 to 8 years, beyond which there may be some significant loss of radiation that may affect the performance of the AMLC (Auto Mould Level Control system) of casting machines.
gamma radiation from this source reaches the detector (NaI- sodium iodide crystal combined with multipliers and/or amplifiers). this detector is actually a geiger counter that counts the amount of radiation by converting it into pulses.
depending upon the amount of steel that interferes the path of radiation from source to detector, there is a proportionate loss of radiation detected by the detector. higher the interference, higher the loss. the system is calibrated using a solid-steel-calibration-block which simulates full mould level (by attenuating the radiation from reaching the detector), and without that block for empty mould level (this latter allows maximum radiation to reach detector).
once the amount of pulses for full and empty mould are registered, it now becomes an interpolation between these two levels, indirectly proportional to the pulses received for any intermediate levels of liquid steel in mould.
the indepth details shall be looked into but later on another post. :-)
this following pics show the physical elements necessary to measure mould level in a continuous casting machine.
in the first pic, at the center is the mould, at the bottom we have the detector, and at the top lies the radioactive source.
in the second pic, the center has mould, at the right is radioactive source that looks like a round canister, at the left lies the detector. the orange coloured box is the electrical cable connectors housing of Mould-Electro Magnetic Stirrer (M-EMS, not to be confused with Micro ElectroMechanical Systems of electronics industry).
this following, third-pic of this post shows radioactive source from the casters side (while the first shown from secondary metallurgy units' or turret side). radiation warning sign is very much clearly visible in this pic below.
the picture above shows the mould of square billet sized 150mm . i created this in visual studio to understand start of casting steps, as the mould gets filled, dummybar withdrawal, filling up of mould to reach the target of around 150mm in detected range, the auto withdrawal start, auto regulation of level to meet the target level.
the pic below shows the schematic mould setup in CCMs; the mould water flow is also shown along with AMLC detection details.
gamma radiation from this source reaches the detector (NaI- sodium iodide crystal combined with multipliers and/or amplifiers). this detector is actually a geiger counter that counts the amount of radiation by converting it into pulses.
depending upon the amount of steel that interferes the path of radiation from source to detector, there is a proportionate loss of radiation detected by the detector. higher the interference, higher the loss. the system is calibrated using a solid-steel-calibration-block which simulates full mould level (by attenuating the radiation from reaching the detector), and without that block for empty mould level (this latter allows maximum radiation to reach detector).
once the amount of pulses for full and empty mould are registered, it now becomes an interpolation between these two levels, indirectly proportional to the pulses received for any intermediate levels of liquid steel in mould.
the indepth details shall be looked into but later on another post. :-)
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