Methods for measuring furnace column curvature
Thread Content
Regarding the methods for measuring the curvature of furnace columns, I have always used the three-line method; this is what is described in textbooks at school, as well as in the factories I have visited before. The formula for it is: Curvature W = (a-b) + (c-a)k. I recently went to apply for a job at a company and was asked this question; I still said that the three-line method is used for measurement. But the interviewer said it was wrong; it should be the five-line method. Who knows what the formula for the five-line method is? Where are the five lines roughly located? (III) The positions of the upper horizontal bar, lower horizontal bar, and grating bricks; the curvature formula was derived based on the similarity of triangles. What about the five lines? How was the formula derived? ）
The five lines for furnace body expansion include additional lines for measuring expansion at the small burner (thermal expansion at the furnace top) and in the chute area. The three-line method is still used to specifically calculate the curvature of the furnace column. I have used a device for measuring the 7 lines of furnace body expansion, and the calculation of furnace column curvature also employs the three-line method
To measure the expansion of the furnace body, a five-wire or seven-wire system can be used; to be exaggerative, it is even more accurate to use a hundred-wire system for measuring such expansion (or furnace length). The question is: How many wires are used as the standard for measuring the curvature of the furnace column?
Personally, I think the three-line method is sufficient; what we need is to monitor the trend in changes in the curvature of the furnace column. High precision is not necessary; therefore, what matters is controllability rather than accuracy. Furthermore, for a curve, there is not much difference between measuring the fifth line and the third line.
Additionally, we can consider the issue of furnace column curvature from another perspective, that is, by performing a finite element analysis on the entire furnace column. Assume for now that the springs at the top and bottom of the furnace column are completely fixed. In that case, the point on this furnace column where the expansion pressure causes the greatest deformation must be the point with the maximum bending moment; therefore, this point should be located near the lower crossbeam. If you don’t believe it, you can create a 3D model to simulate this situation yourself.