they put a clamp with a length of rod on the end of the lance then dip at a said height,they then take a measurement of the dipped rod ,this measurement gives you the bath height which determines the lance heights when you blow the vessel.thankyou from a 26 year bos steelworker and now a coke oven worker DAM!!!
The measure is to the brick lined bottom of the B.O.F. vessel, not to the top of the bath. As the water cooled oxygen lance is lowered, it already blowing oxygen at supersonic speed into the furnace. Steel does build up on the end of the lance and must be removed from time to time. The lances must be taken out of service and repaired occasionally. The lance tip is concave and not flat and has holes at angles to "stir" the steel bath. From a 31 year steelworker.
MuellerNick, thanks for your possible answer to this question put before the world. I continue to wish someone out there who works directly with a BOF would come forth to explain exactly how they position the oxygen lance just above the molten iron. Till then, my nights are still restless pondering the answer!
@hudson501 My guess is that they monitor the pressure in the lance. If the oxygen leaves into free air, you have a certain pressure (depending on mass of oxygen passing through the lance). As soon as the lance dips into the iron, the pressure will rise. The deeper, the higher the backpressure. You can make that experiment with a glass of water and a straw. But I'm just guessing!
I'm sure it's just some sort of measuring system. they know how much iron they put in there (by volume). There fore they know how much distance there is from the top of the vessel to the top of the iron.
Thanks to you (salemcripple) and "chuckbass1" for highlighting how the oxygen lance may be positioned. This is one of those "unanswered questions of the universe" that few people know the answer to.
How do they know when the oxygen lance is just above the molten iron in the BOF process? I've always wondered about this and nobody I know seems to know!!!
Some day, perhaps when we're long gone, someone will come forth with the answer on how the lance is held just above the molten bath. Till then, I will toss and turn in my sleep pondering the potential answer.
Where I am, they have a device called an "Audio Reamer". To my best knowledge, this device is located in the upper sections of the ducting, and is tuned to send a signal when the lance is at the perfect height. Basically, there is a set range of frequencies it will look for, and the lance height is adjusted automatically based on this. This should keep the lance just above the bath at all times whilst on blow. 9 years too late but hopefully helps!
Found something, did a little digging: Audiometry is regarded as perhaps the most accurate method today. It is, like lance vibration, a simple technique reacting mainly to a single process phenomenon, in this case to the noise created by the oxygen jet. The equipment is, however, sensitive to dust contamination. The drawbacks are similar to the ones for lance vibration; the need for the lance tip to become submerged into the foam and a complete horizontal foam coverage within the vessel. Therefore, a usable signal is not obtained in the very early stages of the blow.
they put a clamp with a length of rod on the end of the lance then dip at a said height,they then take a measurement of the dipped rod ,this measurement gives you the bath height which determines the lance heights when you blow the vessel.thankyou from a 26 year bos steelworker and now a coke oven worker DAM!!!
The measure is to the brick lined bottom of the B.O.F. vessel, not to the top of the bath. As the water cooled oxygen lance is lowered, it already blowing oxygen at supersonic speed into the furnace. Steel does build up on the end of the lance and must be removed from time to time. The lances must be taken out of service and repaired occasionally. The lance tip is concave and not flat and has holes at angles to "stir" the steel bath. From a 31 year steelworker.
MuellerNick, thanks for your possible answer to this question put before the world. I continue to wish someone out there who works directly with a BOF would come forth to explain exactly how they position the oxygen lance just above the molten iron. Till then, my nights are still restless pondering the answer!
@hudson501
My guess is that they monitor the pressure in the lance. If the oxygen leaves into free air, you have a certain pressure (depending on mass of oxygen passing through the lance). As soon as the lance dips into the iron, the pressure will rise. The deeper, the higher the backpressure.
You can make that experiment with a glass of water and a straw.
But I'm just guessing!
I'm sure it's just some sort of measuring system. they know how much iron they put in there (by volume). There fore they know how much distance there is from the top of the vessel to the top of the iron.
Thanks to you (salemcripple) and "chuckbass1" for highlighting how the oxygen lance may be positioned. This is one of those "unanswered questions of the universe" that few people know the answer to.
lol, i think we need to get the nations top scientists on this problem ASAP. It could be a problem of grave importance!
Very instructive! Thanks for sharing.
How do they know when the oxygen lance is just above the molten iron in the BOF process? I've always wondered about this and nobody I know seems to know!!!
lol
Where is your operation?? is it in a time or a place?
I just assumed lol i'm not sure.
@daltonagre eu também.
Some day, perhaps when we're long gone, someone will come forth with the answer on how the lance is held just above the molten bath. Till then, I will toss and turn in my sleep pondering the potential answer.
Where I am, they have a device called an "Audio Reamer". To my best knowledge, this device is located in the upper sections of the ducting, and is tuned to send a signal when the lance is at the perfect height. Basically, there is a set range of frequencies it will look for, and the lance height is adjusted automatically based on this. This should keep the lance just above the bath at all times whilst on blow. 9 years too late but hopefully helps!
Found something, did a little digging: Audiometry is regarded as perhaps the most accurate method today. It is, like lance vibration, a simple technique reacting mainly to a single process phenomenon, in this case to the noise created by the oxygen jet. The equipment is, however, sensitive to dust contamination. The drawbacks are similar to the ones for lance vibration; the need for the lance tip to become submerged into the foam and a complete horizontal foam coverage within the vessel. Therefore, a usable signal is not obtained in the very early stages of the blow.