CA2028505A1 - Hollow shell deflection reading system - Google Patents
Hollow shell deflection reading systemInfo
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- CA2028505A1 CA2028505A1 CA 2028505 CA2028505A CA2028505A1 CA 2028505 A1 CA2028505 A1 CA 2028505A1 CA 2028505 CA2028505 CA 2028505 CA 2028505 A CA2028505 A CA 2028505A CA 2028505 A1 CA2028505 A1 CA 2028505A1
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- kiln
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- variations
- rotation
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Abstract
ABSTRACT OF THE DISCLOSURE
A direct reading ovality sensing and recording system for attachment to the outer surface of the steel shell of a kiln or like rotary processing equipment, utilizes a so-called dial (or depth) testing indicator (DTI) mounted upon a short chordal bridge. The instrument directly measures fluctuations in the distance between the surface of the kiln shell and the centre of the bridge. The digital electronic output from the DTI is recorded in a data logger, during the rotation of the kiln, under normal working conditions. The primary use of the system is to accurately measure the actual conditions of flexing of the steel shell, with a view to optimizing the service life of the refractory lining carried in the interior of the kiln. Additionally, a qualitative indication of kiln alignment at the respective pier supports can also be ascertained. In the case of high temperature kilns, where a high thermal gradient acting on the structure of the chordal bridge may produce transient deformation thereof, so as to affect the DTI readings, the system facilitates quantitative evaluation of such thermal deformation, so that the readings may be correspondingly compensated.
A direct reading ovality sensing and recording system for attachment to the outer surface of the steel shell of a kiln or like rotary processing equipment, utilizes a so-called dial (or depth) testing indicator (DTI) mounted upon a short chordal bridge. The instrument directly measures fluctuations in the distance between the surface of the kiln shell and the centre of the bridge. The digital electronic output from the DTI is recorded in a data logger, during the rotation of the kiln, under normal working conditions. The primary use of the system is to accurately measure the actual conditions of flexing of the steel shell, with a view to optimizing the service life of the refractory lining carried in the interior of the kiln. Additionally, a qualitative indication of kiln alignment at the respective pier supports can also be ascertained. In the case of high temperature kilns, where a high thermal gradient acting on the structure of the chordal bridge may produce transient deformation thereof, so as to affect the DTI readings, the system facilitates quantitative evaluation of such thermal deformation, so that the readings may be correspondingly compensated.
Description
20~8~
HOLLOW SHELL DEFLECTION READING SYSTEM
TECHNICAL ~IELD
This invention is directed to a system for measuring the local deflections taking place in the shell of a hollow rotating body, and in particular, that of a rotary kiln; and it lncludes a distance measuring and recordal apparatus for such system.
BACKGROUND TO l'HE INVENTION
The operation and service life of the refractory lining of a hot rotary kiln is heavily dependent upon the operating characteristics of the steel shell of the kiln, in which the lining is installed.
Hot rotary kilns, such as cement kilns and the like, may be several hundred feet in length, having a comparatively thin steel shell ranging from eight to twenty feet in diameter, supported on a series of steel tires, carried upon supporting rollers. The rollers in turn are mounted upon a series of tall piers of sequentially diminishing height, which provides the desired downslope between the inlet and the outlet of the kiln.
The typical daily throughput of a cement kiln is generally such that heavy financial penalties are incurred when the kiln is inoperative; futhermore, the rebricking of the refractory lining is prohibitively expensive. Thus, a strong incentive exists to optimize the working conditions of the kiln, to achieve maximum service life of the refractory lining, and to minimize down time.
Owing to the conditions of operating at high temperatures while revolving slowly about its polar axis, with a dynamically varying load passing along its length, the kiln shell has a series of pads interposed between the shell and the tire, with a clearance provided between the pads and the tire (when cold) to allow for differential thermal expansion between shell and tire under normal operating conditions.
The refractory lining is generally installed within 2~2~0~
the shell of the kiln in a dry laid condition i.e. without mortar, depending upon the arch principal to keep it locked in a continuous arc.
Excessive flexing of the kiln shell in its rotation can permit or induce flexing of the arch to the extent that the arch fails, and collapses.
Dynamic changes of curvature of a kiln shell during its operating rotation are affected by a number of factors:
1. The size of the supporting steel tires in regard to their diameter, thickness and width.
2. The size of the supporting rollers in regard to their diameter and width.
HOLLOW SHELL DEFLECTION READING SYSTEM
TECHNICAL ~IELD
This invention is directed to a system for measuring the local deflections taking place in the shell of a hollow rotating body, and in particular, that of a rotary kiln; and it lncludes a distance measuring and recordal apparatus for such system.
BACKGROUND TO l'HE INVENTION
The operation and service life of the refractory lining of a hot rotary kiln is heavily dependent upon the operating characteristics of the steel shell of the kiln, in which the lining is installed.
Hot rotary kilns, such as cement kilns and the like, may be several hundred feet in length, having a comparatively thin steel shell ranging from eight to twenty feet in diameter, supported on a series of steel tires, carried upon supporting rollers. The rollers in turn are mounted upon a series of tall piers of sequentially diminishing height, which provides the desired downslope between the inlet and the outlet of the kiln.
The typical daily throughput of a cement kiln is generally such that heavy financial penalties are incurred when the kiln is inoperative; futhermore, the rebricking of the refractory lining is prohibitively expensive. Thus, a strong incentive exists to optimize the working conditions of the kiln, to achieve maximum service life of the refractory lining, and to minimize down time.
Owing to the conditions of operating at high temperatures while revolving slowly about its polar axis, with a dynamically varying load passing along its length, the kiln shell has a series of pads interposed between the shell and the tire, with a clearance provided between the pads and the tire (when cold) to allow for differential thermal expansion between shell and tire under normal operating conditions.
The refractory lining is generally installed within 2~2~0~
the shell of the kiln in a dry laid condition i.e. without mortar, depending upon the arch principal to keep it locked in a continuous arc.
Excessive flexing of the kiln shell in its rotation can permit or induce flexing of the arch to the extent that the arch fails, and collapses.
Dynamic changes of curvature of a kiln shell during its operating rotation are affected by a number of factors:
1. The size of the supporting steel tires in regard to their diameter, thickness and width.
2. The size of the supporting rollers in regard to their diameter and width.
3. The axial spacing of the tires along the kiln.
4. The dead (self weight) loading and live loading (moving charge), the latter being variable.
5. The operational radial clearance gap between the tire and the shell.
6. The steady state temperatures of the shell and respective supporting components.
7. The strength of the shell and its associated components.
8. The alignment of the shell upon its supporting rolls. .
The significance and effect of each of the above factors can vary from kiln to kiln, and even from time to time for the same kiln.
Measurement of kiln shell deflections, taken during normal operations of the kiln, was taught by Kareby, in U.S.
Patent No. 2,676,867. This showed the use of a chordal beam, physically secured to the exterior of the kiln shell at a selected point, by way of a chain extending about the shell.
The beam carried a feeler or feeling member, providing contact with the outer surface of the shell, and being responsive to radial deflections of the shell surface, relative to the secured chordal beam.
Relative movement of the feeler to the chordal beam was `::
~2~
translated into movement of a recording member such as pen or pencil against a drum mounted chart. Rotation of the chart drum was provided by a hanging weight, so as to maintain the chart drum rotationally static during its orbiting of the kiln polar axis. The displacement of the recording member in response to radial deflections of the kiln shell as it rotated were translated by a mechanical linkage into repositioning of the recording member in a polar direction, relative to the chart drum, to thus give a trace upon the chart, proportional to the extent of radial deflections of the shell and of the feeler.
This early work was not without merit, but was subject to mechanical inaccuracies, while the apparatus was difficult to install and reposition on the kiln shell.
Subsequent work, along the same lines, carried out by the HOLDERBANK company was based upon a mathematical development published by G. R~SENBLAD "Radiale Deformation von Drehofenmanteln" ZRG7 (1954) publication No. 4 wherein the mathematical relationship between shell deformation, and shell .-ovality is expressed as follows:
w = 2(a-b) where a = major radius of shell b = minor radius of shell.
and where d - extent of deformation = a-b (i.e. the greatest difference between elipse radii) From Rosenblad Wa = 2(a-b) = q' 3 d2/l . ~ m.m.
In the case oE kilns having diameter d less than 2 meters 3 / ~ [L + /l 2 (L/d) 2 + 7 / 2 4 (L/d)4 + l5/ (L/d) 6 ] 1 ~ 2 where d = kiln shell external diameter (meters) L = Basic chordal length of measuring beam (one meter) ~ = greatest deflection measurement (mm) To enabl.e comparisons of ovality for kilns of different diameters, the relative ovality Wr is used, wherein the actual ovality is expressed as a percentage of the kiln 2~23~
internal diameter:
where Wr = Wa . 100 %
dn dn being the kiln internal dlameter in meters.
It has been established in the past, in practice, that to avoid an undue rate of kiln lining wear as a consequence of kiln flexure, the ovality of the shell must stay below certain limits. The limit on acceptable ovality increases with kiln diameter.
Thus for kilns up to 3.5 meters diameter the upper limit of relative ovality is approximately 0.3 %. Greater values of ovality will lead to undue wear or the collapse of the refractory arch.
For kilns of 6 meters diameter the upper safe limit of ovality is approximately 0.5 %. In the past the Holderbank organization relied upon an instrument known as the "Shelltest" instrument. This comprises a one meter chordal beam secured to the outer surface of the kiln shell, generally by magnets, having a centre mounted feeler pin to contact the shell surface below the centre of the beam, and a precision gear transmission to multiply the displacement of the feeler pin by a multiplying factor such as 15.
In the Shelltest instrument, a development of the Kareby arrangement, a pencil marker is displaced laterally as an output of the multiplier mechanism, and a graphic chart carried upon a disk is provided to receive the pencil markings, the chart being rotated by the rotation of the kiln, under the influence of a stabilizing ballast weight.
The output of the prior art Shelltest instrument comprises a so-called polar diagram, matched to the rotation of the kiln shell and having a roughly circular trace, the radial variations of which from a three inch base circle represent the multiplied shell displacement.
In attempting to use diagrams such as those of Kareby or the Shelltest system for purposes of calculating relative ovalit~, it will be understood that inaccuracies arising from . . . ~ ~ . ., ---`` 2 0 ~
factors such as the width of the pencil trace can seriously adversely affect the accuracy of the result, with consequent inability to reliably determine whether or not kiln ovality lies within or outside prescribed safe limits as referred to above, to ensure the satisfactory service life of the refractory lining.
The deficiencies of the prior instruments are compounded by the fact that it is usual practlce to make three characteristic deflection traces on each chart, with the distinct possibility that the traces may partially overlap or o~er-run each other, to further complicate the extraction of accurate information therefrom. It should be born in mind that the ovality measurements being made consist of radial deviations of the polar trace from a theoretical line representing the undeformed outer periphery of the shell. In the case of Shelltest this is on a paper disc some 6 inches in diameter.
The drawbacks of the later Shelltest prior art system, in regard to accuracy are accentuated by the use of a precision motion multiplying device, with its inherent backlash, and vulnerability to general abuse and the adverse effect of a high temperature environment and variation therein, of the kiln.
Furthermore, the deflection measuring and multiplier device, and the di.sc recording means therefor are expensive and heavy, and have been known co dislodge the magnetic mounts by which the 1-meter bridge adheres to the outer surface of the shell.
SUMMARY OF THE INVENTION
The present invention provides a simple, reliable system for directly and accurately measuring and recording the radial deflections taking place in a rotatlng shell, such as a kiln shell, enabling the provision of highly accurate graphs, plotting radial shell deflection for the respective rotational positions of the shell. --2 ~
The apparatus o~ the system can be readily installed and repositioned upon a kiln shell rotating at relatively high speeds, under fully operational conditions for the kiln.
The present invention thus provides a method for determining variations in the radial deflection of a cylindrical shell during its rotation upon supporting rollers, comprising the steps of securing a deflection sensor in spaced relation from a surf~ce portion of the shell to directly monitor variations in the distance of the surface of the shell from the sensor, and recording the distance variation during rotation of the shell.
The present invention further provides a method of directly and accurately measuring radial deflections of a rotating shell, to obtain an accurate graphic representation of shell ovality.
The apparatus of the present system preferably includes a deflection sensor comprising an electronic instrument having a digital read-out, preferably used with a short beam constituting an external chord of the shell, and recordal means for recording the read-out values of the deflection sensor during rotation of the shell.
In the preferred embodiment the short beam is secured by magnetic mounting means in spac.ed relation upon the periphery of the shell, the beam preferably also supporting a data logger for recording the digital readout of the electronic DTI.
With the preferred data logger/instrument combination the variations in distance measured by the DTI are recorded at selected time intervals, and stored in an on-golng basis for later transfer to a computing device for subsequent compilation.
The total readings, comprising as many as 42 sets of data, with each set containing up to 100 readings, may be held in the logger instrument. The data is provided in a form suitable for being directly imported into a computer equipped with a popular, standard spread sheet program such as LOTUS
2~2~
1-2-3 (T.M.), for ease of data manlpulation and for graphing.
The present method may be used with the shell in a heated, operational condition.
The tabulated readings of DTI digital values can be readily plotted as a graph or graphs, on a time basis. This may be readily converted to a rotational basis, in terms of the position of the shell. -In the case of the high temperature kilns, a high thermal gradient acting on the structure of the chordal bridge or beam, may cause it to deform or bow, with a transient deformation, as the beam heats up from an air ambient condition towards the temperature of the shell.
Such transient thermal deformation distorts the value of the DTI readings that are then obtained, as if the shell had "pushed out".
By taking successive readings at 360 intervals, the effect of the therma]. gradient can be readily detected, graphically or statistically, and the DTI values correspondingly corrected. AS the transient thermal effects lie along a sensibly straight line curve, determination of the curve, from readings taken 360 apart, enables offsetting allowances to be accurately calculated and applied. This thermal gradient correction is generally only of significance for surface temperatures at about 700F or higher.
BRIEF DESCRIPTION OF THE DRAWINGS
Certain embodiments of the prior art, and of the pres-ent invention are described by way of illustration, without limitation of the invention to the illustrations thereof, reference being made to the accompanying drawings, wherein:
Figure 1 is a side elevation showing a typical kiln arrangement, to which the prior art and the present system is applied;
Figure 2 is a side elevation of a prior art graphic multiplier and polar diagram recorder;
Figure 3 is a prior art polar diagram as obtained from 20~Q~
the Figure 2 device;
Figure 4 is an ovality limit diagram showing the limits .
of acceptable ovality for a range of kiln diameters;
Figure 5 is an end view of a shell portion having an apparatus for the deflection measuring and recordal system of the present invention mounted upon a magnetically secured chordal beam;
Figure 6 is a diagrammatic end view of a typical shell-support roller arrangement;
Figure 7 is a plot of a normal ovality curve, on a base of shell rotational positions;
Figures 8-12 are plots of particular eccentricity curves for specific shell conditions;
Figure 13 is a plot of actual measurements from a kiln shell, using the present invention; and, Figure 14 is a plot similar to Figure 13~ for a kiln shell, showing the transient effects of high thermal gradient upon the beam.
BEST MODE OF THE CARRYING OUT THE INVENTION
Referring to Figure 1, a hot kiln 20, carried upon piers 22, 24, 26 and 28 has tires 29 mounted upon pairs of rollers 31 carried on the piers, for rotation of the shell 27 about its polar axis.
In Figure 2 the prior art "SHELLTEST" device 33 is mounted upon a chordal bearn in a fashion similar to the pres-ent invention. A body por~ion 34 secured to the supporting beam (not shown) has a feeler pin 35 connecting with a mechan-ical multiplier arrangementi to displace a recordal pencil 37 against a paper card 39 rnounted upon shaft 41, ballasted upright durlng rotation of the shell by weight 43.
The feeler pin 35 bears against a portion 45 of the kiln shell.
In operation, as the kiln portion 45 rotates, it is deformed, causing the feeler pin 35 tc move, as with deflection ~h. This translates into movement of the pencil 37 2~285~
g ,.
across card 39 by a distance M~h where M is a mechanical multiplicant factor with a value such as 15. The shaft 41 being free to rotate, and being ballasted by weight 43 to remain vertical, in the position shown, therefore rotates, relative to the body portion 34, due to the circular displacement of the body portion 34 with the rotating kiln.
This in turn draws the card 39 arcuately past the pencil 37, so as to draw a trace.
Thus, referring to Figure 3, the prior art circular card 39 has a polar deformation plot 41 drawi.ng thereon. The actual deformation, as an ovality, is represented by the difference in radii a and b, being one fifteenth of the dimension represented on the card, when the multiplicand factor M of the mechanism is 15.
It will be evident that an undue degree of accuracy is required in order to extract deflection readings from the polar diagrams that can provide qualitatively reliable values of relative ovality, of sufficient accuracy to place reliance therein in regard to the ovality limit diagram of Figure 4.
Referring to Figure 4, this empirical relation showing the acceptable range of relative ovality, and its variance with shell diameter has been established, and is generally accepted as valid in the industry. . The median value of acceptable relative ovality w ranges from about 0.3% to about 0.5%. Thus the shaded area of the figure represents a working range of acceptable ovality. Ovality values lying above the shaded area indicate undue clearances of the tire and undue flexing of the shell, with an increased probability of failure of the refractory lining.
Values of relative ovality lying below the shaded area generally indicate inadequate clearances between tire and shell, again with the probability of the occurrence of undue wear of the refractory liner.
Referring to Figure 5, the apparatus 40 of the present system is shown mounted on a portion of shell 17 of a kiln.
The apparatus 40 comprises a one meter bridge 42 having a DTI
2~2~
(Dial, Distance or Depth) Test Indicator 43 and data logger 44 mounted thereon.
Magnetic clamps 45 secure adjustable bridge supports 46 to the shell 27.
Adjustable clamps 48 facllitate setting of the bridge 42 in accordance with the diameter of shell 27, and may also permit coarse adjustment for the DTI 43. The DTI 43 is a precision electronic instrument, readily available in a number of commercial models from many manufacturers, having a digital readout that is connected to data logger 44.
The data logger 44 incorporates a timing clock, to provide a time base for each recorded value of the read out provided by DTI 43. Thus, each recorded value of deflection has a corresponding recordal time, which is directly related to the shell rotational position. The data storage facility of the data logger enables the storing of total readings in excess of 4000, for a full logging of a large kiln. These accumulated values of defelection can be downloaded to a computer, for handling by a standard spreadsheet such as LOTUS
1-2-3 (T.M.).
Figure 6 shows the typical arrangement of a shell 27, a tire 29, and a pair of support rollers 31, with indication of the salient points of the shell, as referred to in the following description of Figure 7 through 12.
Thus, with the Top of Shell (Top Dead Centre or TDC) as the location of the system apparatus ~0, upon rotation of the system apparatus ~0 passes sequentially clockwise to the 3-o'clock position, over the right roller 31 to the Bottom Dead Centre (BDC) position. From there past the left roller 31 to the 9-o'clock position, and from there, back to the TDC
starting location.
The arrangement, mass and interconnection of the respective system components and their mode of mounting enables the apparatus to be mounted and respositioned, even at relatively high peripheral speeds, as high as 130 feet per minute, on a 16-foot diameter kiln, for example, and under 2~2~
full operating conditions.
Figure 7 shows a so-called Normal Curve, wherein the shell 27 is well centred on its rolls, and the relative ovality is reasonably within limits.
Referring to the Figure 8 characteristic curve the large spread of eccentricity values indicates either an unduly heavily loaded pier (i.e. probable high live load) or an undersized tire, or that the support rollers are holding the kiln unduly high.
Figure 9 indicated the probability of an underloaded pier (with adjacent piers probably overloaded).
Figure 10, showing a large spread of eccentricity values is probably indicative of an excessive clearance gap between tire 29 and shell 27.
Referring to Figure 11, the curves A and B are taken at the same position along the shell, at the same "cross section", but 180 apart from each other, on the shell periphery, and indicate the shell to be bowed at this support.
In the case of Figure 12, the abrupt change in -curvature is indicative of a crack in the shell plate.
The foregoing interpretations of the characteristic curves yield rapidly available commentaries concerning the kiln support and rotational system, and the rapid and totally accurate eccentricity values may be used to accurately and directly determine shell ovalities, in relation to the acceptable ovality values of Figure 4.
A typical set of shell eccentricity values, as plotted in Figure 13, and obtained from a test carried out on an actual, operating kiln are given below.
A series of seventy two readings, taken at equal time intervals representing one revolution of the shell are given, for a total of six locations adjacent one of the shell tires.
The locations are located adjacent the tire for a selected pier and the shell support bearings, being positioned on the "uphill" and the "downhill" sides of the tire, and at three such locations mutually located at 120 in~ervals, A, B, C about the shell periphery.
- 2~28~
Kiln Diameter: 3,607 meters OD; 3.505 meters ID
Pier#4 Uphill Downhill A B C A B C
%Oval0.500.26 0.32 0.50 0.32 0.32 Range1.010.53 0.65 1.02 0.65 0.65 MaxØ460.27 0.30 0.46 0.28 0.30 Min.-0.55-0.26 -0.35 -0.56 -0.36 -0.35 Maximum change in Dia.: 13.4 mm at BDC: 10.7 mm 10.100.24 0.07 0.10 0.19 -0.03 20.210.26 0.09 0.190.23 -0.01 30.290.26 0.11 0.250.26 0.02 40.350.24 0.14 0.310.27 0.05 50.390.23 0.16 0.360.27 0.07 60.420.20 0.18 0.400.25 0.10 70.440.28 0.20 0.430.23 0.13 80.450.16 0.22 0.450.21 0.15 90.460.11 0.24 0.460.19 0.18 100.460.07 0.25 0.460.14 0.20 110.450.03 0.27 0.460.08 0.23 120.44-0.01 0.28 0.260.04 0.25 130.43-0.05 0.29 0.45-0.01 0.27 140.42-0.08 0.30 0.44-0.05 0.30 150.400.12 0.30 0.43-0.11 0.29 160.39-0.16 0.26 0.41-0.15 0.24 17 0.37 -0.19 0.200.39 -0.19 0.18 18 0.35 -0.21 0.160.36 -0.23 0.13 19 0.33 -0.24 0.100.34 -0.26 0.08 0.31 -0.25 0.050.32 -0.29 0.03 21 0.28 -0.26 0.010.29 -0.32 -0.02 22 0.26 -0.26 -0.040.25 -0.34 -0.02 23 0.23 -0.26 -0.030.21 -0.35 0.00 24 0.20 -0.25 -0.00 0.18 0.36 0.02 0.18 -0.24 0.04 0.15 -0.35 0.07 ~2~
260.15-0.22 0.08 0.13 -0.34 0.11 270.13-0.19 0.120.11 -0.32 0.14 280.11-0.16 0.150.09 -0.29 0.16 290.09-0.12 0.160.09 -0.26 0.17 300.09-0.09 0.160.10 -0.23 0.18 310.10-0.04 0.160.12 -0.18 0.19 320.120.00 0.160.15 -0.14 0.20 330.170.04 0.160.20 -0.08 0.20 340.180.07 0.160.20 -0.03 0.20 350.180.11 0.160.20 0.02 0.20 360.170.15 0. lS0.190.06 0.19 370.150.18 0.140.17 0.11 0.18 380.130.21 0.130.16 0.15 0.16 390.110.23 0.120.14 0.19 0.15 400.090.25 0.100.11 0.22 0.13 410.060.26 0.090.08 0.25 0.11 420.030.27 0.070.05 0.28 0.09 43-0.010.27 0.060.00 0.29 0.07 44-0.040.25 0.040.04 0.29 0.05 45-0.070.23 0.02-0.07 0.29 0.02 46-0.100.19 -0.01-0.10 0.27 -0.01 47-0.130.14 -0.04-0.14 0.24 -0.04 48-0.170.07 -0.08-0.18 0.20 -0.08 49-0.200.02 -0.12-0.21 0.13 -0.13 50-0.24-0.02 -0.17-0.26 0.08 -0.18 51-0.28-0.05 -0.22--0.31 0.03 -0.24 52-0.33-0.08 -0.26-0.36 0.00 -0.29 53-0.38-0.11 -0.30-0.42 -0.03 -0.32 54-0.43-0.13 -0.33-0.47 -0.06 -0.34 55-0.48-0.14 -0.35-0.51 -0.09 -0.35 56-0.51-0.14 -0.35-0.54 -0.10 -0.34 57-0.54-0.14 -0.33-0.55 -0.11 -0.31 58-0.55-0.14 -0.31-0.56-0. ll -0.29 59-0.54-0.13 -0.29-0.54 -0.10 -0.26 60-0.52-0.11 -0.27-0.52 -0.08 -0.24 61-0.50-0.09 -0.25-0.50 -0.07 -0.23 62 -0.48-0.08 -0.25 -0.48-0.04 -0.23 -0.25*
63 --0.47-0.08 -0.25 -0.46-0.03 -0.22 64 -0.46-0.08 -0.26 -0.46-0.03 -0.23 65 -0.47-0.08 -0.26 -0.45-0.03 -0.24 -~
66 -0.48-0.07 -0.27 -0.46-0.04 -0.24 67 -0.50-0.06 -0.26 -0.47-0.05 -0.24 68 -0.50-0.03 -0.23 -0.48-0.05 -0.22 69 -0.490.00 -0.20 -0.47-0.02 -0.19 70 -0.440.04 -0.16 -0.440.01 -0.15 71 -0.390.08 -0.12 -0.330.05 -0.12 72 -0.270.11 -0.17 -0.180.09 -0.08 Average BDC
Ratio 0.37 0.30 0.75 0.80 0.35 *
-0.40 Delta Radius:
0.211 inches -Ovality is defined, as referred to above, as being twice the difference of major and minor radii of the elliptically deformed section of the kiln.
Using the Rosenblad mathematical relationship to determine ovality w w = 2(a-b) = ~/3 X (OD/L) 2 X deflection (1j The generic rela,tionship presented usually as a percentage of kiln inside diameter, is expressed % ovality = %w = w x ~.00 ID
Where ID = Kiln inside diameter (= 3.353 meters) a = Major ovality radius b = Minor ovality radius 2 ~
L = Base Length (Bridge span) = 1 meter This then yields plots on the Figure 4 ovality acceptability chart, for the respective tire locations.
Referring to Figure 14, this relates to a deflection or ovality plot for a single location, over the course of two full revolutions of the kiln.
With a kiln temperature at or above 700F, the bridge structure is sub~ect to a transient thermal gradient, causing an exaggeration of the shell deflection readings, as can be seen by the gradient of the line A-B. For stable thermal conditions, with no distortion of the fixture bridge 42 (Figure S) the maximum deflections, both positive and negative, should be constant, such that line A-B would parallel the X-axis.
With the transient temperature effect thus plotted for one station, correction factors may be applied to the deflection or 'C' values, both for the Figure 14 graphs, and for other plots taken at the other measurement stations, upstream and downstream of the tire, and about the kiln periphery, where the bridge is located at 120 intervals.
In addition to enabling corrections to be made to the effects of thermal transients upon the apparatus of the present invention, the precision of measurement also enables a skilled practitioner to interpret from the readings much significant information concerning various operating conditions that are affecting the kiln.
Thus, at point D of Figure 14 the discontinuity indicates displacement of the beam upon its mountings, the beam having moved closer to the shell surface.
The point E denotes passage of the beam and DTI
instrument over the left support roller.
Point F represents "BDC", the Bottom Dead Centre position.
Point G denotes passage of the beam and DTI instrument over the right support roller.
Point H denotes the 3-o'clock location and point I the 2~2~
The significance and effect of each of the above factors can vary from kiln to kiln, and even from time to time for the same kiln.
Measurement of kiln shell deflections, taken during normal operations of the kiln, was taught by Kareby, in U.S.
Patent No. 2,676,867. This showed the use of a chordal beam, physically secured to the exterior of the kiln shell at a selected point, by way of a chain extending about the shell.
The beam carried a feeler or feeling member, providing contact with the outer surface of the shell, and being responsive to radial deflections of the shell surface, relative to the secured chordal beam.
Relative movement of the feeler to the chordal beam was `::
~2~
translated into movement of a recording member such as pen or pencil against a drum mounted chart. Rotation of the chart drum was provided by a hanging weight, so as to maintain the chart drum rotationally static during its orbiting of the kiln polar axis. The displacement of the recording member in response to radial deflections of the kiln shell as it rotated were translated by a mechanical linkage into repositioning of the recording member in a polar direction, relative to the chart drum, to thus give a trace upon the chart, proportional to the extent of radial deflections of the shell and of the feeler.
This early work was not without merit, but was subject to mechanical inaccuracies, while the apparatus was difficult to install and reposition on the kiln shell.
Subsequent work, along the same lines, carried out by the HOLDERBANK company was based upon a mathematical development published by G. R~SENBLAD "Radiale Deformation von Drehofenmanteln" ZRG7 (1954) publication No. 4 wherein the mathematical relationship between shell deformation, and shell .-ovality is expressed as follows:
w = 2(a-b) where a = major radius of shell b = minor radius of shell.
and where d - extent of deformation = a-b (i.e. the greatest difference between elipse radii) From Rosenblad Wa = 2(a-b) = q' 3 d2/l . ~ m.m.
In the case oE kilns having diameter d less than 2 meters 3 / ~ [L + /l 2 (L/d) 2 + 7 / 2 4 (L/d)4 + l5/ (L/d) 6 ] 1 ~ 2 where d = kiln shell external diameter (meters) L = Basic chordal length of measuring beam (one meter) ~ = greatest deflection measurement (mm) To enabl.e comparisons of ovality for kilns of different diameters, the relative ovality Wr is used, wherein the actual ovality is expressed as a percentage of the kiln 2~23~
internal diameter:
where Wr = Wa . 100 %
dn dn being the kiln internal dlameter in meters.
It has been established in the past, in practice, that to avoid an undue rate of kiln lining wear as a consequence of kiln flexure, the ovality of the shell must stay below certain limits. The limit on acceptable ovality increases with kiln diameter.
Thus for kilns up to 3.5 meters diameter the upper limit of relative ovality is approximately 0.3 %. Greater values of ovality will lead to undue wear or the collapse of the refractory arch.
For kilns of 6 meters diameter the upper safe limit of ovality is approximately 0.5 %. In the past the Holderbank organization relied upon an instrument known as the "Shelltest" instrument. This comprises a one meter chordal beam secured to the outer surface of the kiln shell, generally by magnets, having a centre mounted feeler pin to contact the shell surface below the centre of the beam, and a precision gear transmission to multiply the displacement of the feeler pin by a multiplying factor such as 15.
In the Shelltest instrument, a development of the Kareby arrangement, a pencil marker is displaced laterally as an output of the multiplier mechanism, and a graphic chart carried upon a disk is provided to receive the pencil markings, the chart being rotated by the rotation of the kiln, under the influence of a stabilizing ballast weight.
The output of the prior art Shelltest instrument comprises a so-called polar diagram, matched to the rotation of the kiln shell and having a roughly circular trace, the radial variations of which from a three inch base circle represent the multiplied shell displacement.
In attempting to use diagrams such as those of Kareby or the Shelltest system for purposes of calculating relative ovalit~, it will be understood that inaccuracies arising from . . . ~ ~ . ., ---`` 2 0 ~
factors such as the width of the pencil trace can seriously adversely affect the accuracy of the result, with consequent inability to reliably determine whether or not kiln ovality lies within or outside prescribed safe limits as referred to above, to ensure the satisfactory service life of the refractory lining.
The deficiencies of the prior instruments are compounded by the fact that it is usual practlce to make three characteristic deflection traces on each chart, with the distinct possibility that the traces may partially overlap or o~er-run each other, to further complicate the extraction of accurate information therefrom. It should be born in mind that the ovality measurements being made consist of radial deviations of the polar trace from a theoretical line representing the undeformed outer periphery of the shell. In the case of Shelltest this is on a paper disc some 6 inches in diameter.
The drawbacks of the later Shelltest prior art system, in regard to accuracy are accentuated by the use of a precision motion multiplying device, with its inherent backlash, and vulnerability to general abuse and the adverse effect of a high temperature environment and variation therein, of the kiln.
Furthermore, the deflection measuring and multiplier device, and the di.sc recording means therefor are expensive and heavy, and have been known co dislodge the magnetic mounts by which the 1-meter bridge adheres to the outer surface of the shell.
SUMMARY OF THE INVENTION
The present invention provides a simple, reliable system for directly and accurately measuring and recording the radial deflections taking place in a rotatlng shell, such as a kiln shell, enabling the provision of highly accurate graphs, plotting radial shell deflection for the respective rotational positions of the shell. --2 ~
The apparatus o~ the system can be readily installed and repositioned upon a kiln shell rotating at relatively high speeds, under fully operational conditions for the kiln.
The present invention thus provides a method for determining variations in the radial deflection of a cylindrical shell during its rotation upon supporting rollers, comprising the steps of securing a deflection sensor in spaced relation from a surf~ce portion of the shell to directly monitor variations in the distance of the surface of the shell from the sensor, and recording the distance variation during rotation of the shell.
The present invention further provides a method of directly and accurately measuring radial deflections of a rotating shell, to obtain an accurate graphic representation of shell ovality.
The apparatus of the present system preferably includes a deflection sensor comprising an electronic instrument having a digital read-out, preferably used with a short beam constituting an external chord of the shell, and recordal means for recording the read-out values of the deflection sensor during rotation of the shell.
In the preferred embodiment the short beam is secured by magnetic mounting means in spac.ed relation upon the periphery of the shell, the beam preferably also supporting a data logger for recording the digital readout of the electronic DTI.
With the preferred data logger/instrument combination the variations in distance measured by the DTI are recorded at selected time intervals, and stored in an on-golng basis for later transfer to a computing device for subsequent compilation.
The total readings, comprising as many as 42 sets of data, with each set containing up to 100 readings, may be held in the logger instrument. The data is provided in a form suitable for being directly imported into a computer equipped with a popular, standard spread sheet program such as LOTUS
2~2~
1-2-3 (T.M.), for ease of data manlpulation and for graphing.
The present method may be used with the shell in a heated, operational condition.
The tabulated readings of DTI digital values can be readily plotted as a graph or graphs, on a time basis. This may be readily converted to a rotational basis, in terms of the position of the shell. -In the case of the high temperature kilns, a high thermal gradient acting on the structure of the chordal bridge or beam, may cause it to deform or bow, with a transient deformation, as the beam heats up from an air ambient condition towards the temperature of the shell.
Such transient thermal deformation distorts the value of the DTI readings that are then obtained, as if the shell had "pushed out".
By taking successive readings at 360 intervals, the effect of the therma]. gradient can be readily detected, graphically or statistically, and the DTI values correspondingly corrected. AS the transient thermal effects lie along a sensibly straight line curve, determination of the curve, from readings taken 360 apart, enables offsetting allowances to be accurately calculated and applied. This thermal gradient correction is generally only of significance for surface temperatures at about 700F or higher.
BRIEF DESCRIPTION OF THE DRAWINGS
Certain embodiments of the prior art, and of the pres-ent invention are described by way of illustration, without limitation of the invention to the illustrations thereof, reference being made to the accompanying drawings, wherein:
Figure 1 is a side elevation showing a typical kiln arrangement, to which the prior art and the present system is applied;
Figure 2 is a side elevation of a prior art graphic multiplier and polar diagram recorder;
Figure 3 is a prior art polar diagram as obtained from 20~Q~
the Figure 2 device;
Figure 4 is an ovality limit diagram showing the limits .
of acceptable ovality for a range of kiln diameters;
Figure 5 is an end view of a shell portion having an apparatus for the deflection measuring and recordal system of the present invention mounted upon a magnetically secured chordal beam;
Figure 6 is a diagrammatic end view of a typical shell-support roller arrangement;
Figure 7 is a plot of a normal ovality curve, on a base of shell rotational positions;
Figures 8-12 are plots of particular eccentricity curves for specific shell conditions;
Figure 13 is a plot of actual measurements from a kiln shell, using the present invention; and, Figure 14 is a plot similar to Figure 13~ for a kiln shell, showing the transient effects of high thermal gradient upon the beam.
BEST MODE OF THE CARRYING OUT THE INVENTION
Referring to Figure 1, a hot kiln 20, carried upon piers 22, 24, 26 and 28 has tires 29 mounted upon pairs of rollers 31 carried on the piers, for rotation of the shell 27 about its polar axis.
In Figure 2 the prior art "SHELLTEST" device 33 is mounted upon a chordal bearn in a fashion similar to the pres-ent invention. A body por~ion 34 secured to the supporting beam (not shown) has a feeler pin 35 connecting with a mechan-ical multiplier arrangementi to displace a recordal pencil 37 against a paper card 39 rnounted upon shaft 41, ballasted upright durlng rotation of the shell by weight 43.
The feeler pin 35 bears against a portion 45 of the kiln shell.
In operation, as the kiln portion 45 rotates, it is deformed, causing the feeler pin 35 tc move, as with deflection ~h. This translates into movement of the pencil 37 2~285~
g ,.
across card 39 by a distance M~h where M is a mechanical multiplicant factor with a value such as 15. The shaft 41 being free to rotate, and being ballasted by weight 43 to remain vertical, in the position shown, therefore rotates, relative to the body portion 34, due to the circular displacement of the body portion 34 with the rotating kiln.
This in turn draws the card 39 arcuately past the pencil 37, so as to draw a trace.
Thus, referring to Figure 3, the prior art circular card 39 has a polar deformation plot 41 drawi.ng thereon. The actual deformation, as an ovality, is represented by the difference in radii a and b, being one fifteenth of the dimension represented on the card, when the multiplicand factor M of the mechanism is 15.
It will be evident that an undue degree of accuracy is required in order to extract deflection readings from the polar diagrams that can provide qualitatively reliable values of relative ovality, of sufficient accuracy to place reliance therein in regard to the ovality limit diagram of Figure 4.
Referring to Figure 4, this empirical relation showing the acceptable range of relative ovality, and its variance with shell diameter has been established, and is generally accepted as valid in the industry. . The median value of acceptable relative ovality w ranges from about 0.3% to about 0.5%. Thus the shaded area of the figure represents a working range of acceptable ovality. Ovality values lying above the shaded area indicate undue clearances of the tire and undue flexing of the shell, with an increased probability of failure of the refractory lining.
Values of relative ovality lying below the shaded area generally indicate inadequate clearances between tire and shell, again with the probability of the occurrence of undue wear of the refractory liner.
Referring to Figure 5, the apparatus 40 of the present system is shown mounted on a portion of shell 17 of a kiln.
The apparatus 40 comprises a one meter bridge 42 having a DTI
2~2~
(Dial, Distance or Depth) Test Indicator 43 and data logger 44 mounted thereon.
Magnetic clamps 45 secure adjustable bridge supports 46 to the shell 27.
Adjustable clamps 48 facllitate setting of the bridge 42 in accordance with the diameter of shell 27, and may also permit coarse adjustment for the DTI 43. The DTI 43 is a precision electronic instrument, readily available in a number of commercial models from many manufacturers, having a digital readout that is connected to data logger 44.
The data logger 44 incorporates a timing clock, to provide a time base for each recorded value of the read out provided by DTI 43. Thus, each recorded value of deflection has a corresponding recordal time, which is directly related to the shell rotational position. The data storage facility of the data logger enables the storing of total readings in excess of 4000, for a full logging of a large kiln. These accumulated values of defelection can be downloaded to a computer, for handling by a standard spreadsheet such as LOTUS
1-2-3 (T.M.).
Figure 6 shows the typical arrangement of a shell 27, a tire 29, and a pair of support rollers 31, with indication of the salient points of the shell, as referred to in the following description of Figure 7 through 12.
Thus, with the Top of Shell (Top Dead Centre or TDC) as the location of the system apparatus ~0, upon rotation of the system apparatus ~0 passes sequentially clockwise to the 3-o'clock position, over the right roller 31 to the Bottom Dead Centre (BDC) position. From there past the left roller 31 to the 9-o'clock position, and from there, back to the TDC
starting location.
The arrangement, mass and interconnection of the respective system components and their mode of mounting enables the apparatus to be mounted and respositioned, even at relatively high peripheral speeds, as high as 130 feet per minute, on a 16-foot diameter kiln, for example, and under 2~2~
full operating conditions.
Figure 7 shows a so-called Normal Curve, wherein the shell 27 is well centred on its rolls, and the relative ovality is reasonably within limits.
Referring to the Figure 8 characteristic curve the large spread of eccentricity values indicates either an unduly heavily loaded pier (i.e. probable high live load) or an undersized tire, or that the support rollers are holding the kiln unduly high.
Figure 9 indicated the probability of an underloaded pier (with adjacent piers probably overloaded).
Figure 10, showing a large spread of eccentricity values is probably indicative of an excessive clearance gap between tire 29 and shell 27.
Referring to Figure 11, the curves A and B are taken at the same position along the shell, at the same "cross section", but 180 apart from each other, on the shell periphery, and indicate the shell to be bowed at this support.
In the case of Figure 12, the abrupt change in -curvature is indicative of a crack in the shell plate.
The foregoing interpretations of the characteristic curves yield rapidly available commentaries concerning the kiln support and rotational system, and the rapid and totally accurate eccentricity values may be used to accurately and directly determine shell ovalities, in relation to the acceptable ovality values of Figure 4.
A typical set of shell eccentricity values, as plotted in Figure 13, and obtained from a test carried out on an actual, operating kiln are given below.
A series of seventy two readings, taken at equal time intervals representing one revolution of the shell are given, for a total of six locations adjacent one of the shell tires.
The locations are located adjacent the tire for a selected pier and the shell support bearings, being positioned on the "uphill" and the "downhill" sides of the tire, and at three such locations mutually located at 120 in~ervals, A, B, C about the shell periphery.
- 2~28~
Kiln Diameter: 3,607 meters OD; 3.505 meters ID
Pier#4 Uphill Downhill A B C A B C
%Oval0.500.26 0.32 0.50 0.32 0.32 Range1.010.53 0.65 1.02 0.65 0.65 MaxØ460.27 0.30 0.46 0.28 0.30 Min.-0.55-0.26 -0.35 -0.56 -0.36 -0.35 Maximum change in Dia.: 13.4 mm at BDC: 10.7 mm 10.100.24 0.07 0.10 0.19 -0.03 20.210.26 0.09 0.190.23 -0.01 30.290.26 0.11 0.250.26 0.02 40.350.24 0.14 0.310.27 0.05 50.390.23 0.16 0.360.27 0.07 60.420.20 0.18 0.400.25 0.10 70.440.28 0.20 0.430.23 0.13 80.450.16 0.22 0.450.21 0.15 90.460.11 0.24 0.460.19 0.18 100.460.07 0.25 0.460.14 0.20 110.450.03 0.27 0.460.08 0.23 120.44-0.01 0.28 0.260.04 0.25 130.43-0.05 0.29 0.45-0.01 0.27 140.42-0.08 0.30 0.44-0.05 0.30 150.400.12 0.30 0.43-0.11 0.29 160.39-0.16 0.26 0.41-0.15 0.24 17 0.37 -0.19 0.200.39 -0.19 0.18 18 0.35 -0.21 0.160.36 -0.23 0.13 19 0.33 -0.24 0.100.34 -0.26 0.08 0.31 -0.25 0.050.32 -0.29 0.03 21 0.28 -0.26 0.010.29 -0.32 -0.02 22 0.26 -0.26 -0.040.25 -0.34 -0.02 23 0.23 -0.26 -0.030.21 -0.35 0.00 24 0.20 -0.25 -0.00 0.18 0.36 0.02 0.18 -0.24 0.04 0.15 -0.35 0.07 ~2~
260.15-0.22 0.08 0.13 -0.34 0.11 270.13-0.19 0.120.11 -0.32 0.14 280.11-0.16 0.150.09 -0.29 0.16 290.09-0.12 0.160.09 -0.26 0.17 300.09-0.09 0.160.10 -0.23 0.18 310.10-0.04 0.160.12 -0.18 0.19 320.120.00 0.160.15 -0.14 0.20 330.170.04 0.160.20 -0.08 0.20 340.180.07 0.160.20 -0.03 0.20 350.180.11 0.160.20 0.02 0.20 360.170.15 0. lS0.190.06 0.19 370.150.18 0.140.17 0.11 0.18 380.130.21 0.130.16 0.15 0.16 390.110.23 0.120.14 0.19 0.15 400.090.25 0.100.11 0.22 0.13 410.060.26 0.090.08 0.25 0.11 420.030.27 0.070.05 0.28 0.09 43-0.010.27 0.060.00 0.29 0.07 44-0.040.25 0.040.04 0.29 0.05 45-0.070.23 0.02-0.07 0.29 0.02 46-0.100.19 -0.01-0.10 0.27 -0.01 47-0.130.14 -0.04-0.14 0.24 -0.04 48-0.170.07 -0.08-0.18 0.20 -0.08 49-0.200.02 -0.12-0.21 0.13 -0.13 50-0.24-0.02 -0.17-0.26 0.08 -0.18 51-0.28-0.05 -0.22--0.31 0.03 -0.24 52-0.33-0.08 -0.26-0.36 0.00 -0.29 53-0.38-0.11 -0.30-0.42 -0.03 -0.32 54-0.43-0.13 -0.33-0.47 -0.06 -0.34 55-0.48-0.14 -0.35-0.51 -0.09 -0.35 56-0.51-0.14 -0.35-0.54 -0.10 -0.34 57-0.54-0.14 -0.33-0.55 -0.11 -0.31 58-0.55-0.14 -0.31-0.56-0. ll -0.29 59-0.54-0.13 -0.29-0.54 -0.10 -0.26 60-0.52-0.11 -0.27-0.52 -0.08 -0.24 61-0.50-0.09 -0.25-0.50 -0.07 -0.23 62 -0.48-0.08 -0.25 -0.48-0.04 -0.23 -0.25*
63 --0.47-0.08 -0.25 -0.46-0.03 -0.22 64 -0.46-0.08 -0.26 -0.46-0.03 -0.23 65 -0.47-0.08 -0.26 -0.45-0.03 -0.24 -~
66 -0.48-0.07 -0.27 -0.46-0.04 -0.24 67 -0.50-0.06 -0.26 -0.47-0.05 -0.24 68 -0.50-0.03 -0.23 -0.48-0.05 -0.22 69 -0.490.00 -0.20 -0.47-0.02 -0.19 70 -0.440.04 -0.16 -0.440.01 -0.15 71 -0.390.08 -0.12 -0.330.05 -0.12 72 -0.270.11 -0.17 -0.180.09 -0.08 Average BDC
Ratio 0.37 0.30 0.75 0.80 0.35 *
-0.40 Delta Radius:
0.211 inches -Ovality is defined, as referred to above, as being twice the difference of major and minor radii of the elliptically deformed section of the kiln.
Using the Rosenblad mathematical relationship to determine ovality w w = 2(a-b) = ~/3 X (OD/L) 2 X deflection (1j The generic rela,tionship presented usually as a percentage of kiln inside diameter, is expressed % ovality = %w = w x ~.00 ID
Where ID = Kiln inside diameter (= 3.353 meters) a = Major ovality radius b = Minor ovality radius 2 ~
L = Base Length (Bridge span) = 1 meter This then yields plots on the Figure 4 ovality acceptability chart, for the respective tire locations.
Referring to Figure 14, this relates to a deflection or ovality plot for a single location, over the course of two full revolutions of the kiln.
With a kiln temperature at or above 700F, the bridge structure is sub~ect to a transient thermal gradient, causing an exaggeration of the shell deflection readings, as can be seen by the gradient of the line A-B. For stable thermal conditions, with no distortion of the fixture bridge 42 (Figure S) the maximum deflections, both positive and negative, should be constant, such that line A-B would parallel the X-axis.
With the transient temperature effect thus plotted for one station, correction factors may be applied to the deflection or 'C' values, both for the Figure 14 graphs, and for other plots taken at the other measurement stations, upstream and downstream of the tire, and about the kiln periphery, where the bridge is located at 120 intervals.
In addition to enabling corrections to be made to the effects of thermal transients upon the apparatus of the present invention, the precision of measurement also enables a skilled practitioner to interpret from the readings much significant information concerning various operating conditions that are affecting the kiln.
Thus, at point D of Figure 14 the discontinuity indicates displacement of the beam upon its mountings, the beam having moved closer to the shell surface.
The point E denotes passage of the beam and DTI
instrument over the left support roller.
Point F represents "BDC", the Bottom Dead Centre position.
Point G denotes passage of the beam and DTI instrument over the right support roller.
Point H denotes the 3-o'clock location and point I the 2~2~
9-o'clock location.
The lines J, K and L may be regarded as typical misalignment signatures, indicating that the kiln is non-symetrically deformed at the subject pier support rollers, due to lateral offset of the support rollers to one side, relative to the kiln "ideal" axis. This is referred to as a dog leg.
Thus it can be seen that the present system constitutes a tool of very large potential, in the hands of a skilled practitioner. furthermore, the results are substantially repeatable, and it is contemplated that the interpretation thereof probably also lends itself to computerization.
INDUSTRIAL APPLICABILITY
This apparatus and its method of use have worldwide industrial applicability wherever kilns and like rotating bodies, subject to deformation and wear, are in use.
The lines J, K and L may be regarded as typical misalignment signatures, indicating that the kiln is non-symetrically deformed at the subject pier support rollers, due to lateral offset of the support rollers to one side, relative to the kiln "ideal" axis. This is referred to as a dog leg.
Thus it can be seen that the present system constitutes a tool of very large potential, in the hands of a skilled practitioner. furthermore, the results are substantially repeatable, and it is contemplated that the interpretation thereof probably also lends itself to computerization.
INDUSTRIAL APPLICABILITY
This apparatus and its method of use have worldwide industrial applicability wherever kilns and like rotating bodies, subject to deformation and wear, are in use.
Claims (14)
1. A system for determining variations in the radial deflection of a thin cylindrical shell supported for rotation upon pairs of rollers, during rotation of the shell upon said rollers, said system including a short beam constituting a minor external chord of the shell, attachment means for removably securing the beam to an exterior surface portion of the shell; an electronic deflection sensor responsive to radial changes in the location of the shell outer surface relative to said beam; and recordal means for recording read out values of said deflection sensor during rotation of said kiln.
2. The system as set forth in claim 1, said deflection sensor comprising an electronic instrument having a digital read out.
3. The system as set forth in claim 2, said recordal means being mounted upon said beam for rotation therewith during operation of the kiln.
4. The system as set forth in claim 1, said attachment means comprising magnet means for removably securing the ends of said beam in readily detachable relation with an outer surface portion of said shell.
5. The system as set forth in claim 3, said recordal means including timing means, in use to record the successive readings of said deflection sensor at equal time intervals.
6. The system as set forth in claim 1, said recordal means having sufficient capacity to record eccentricity readings for the entire said shell, for subsequent read-out to a computer.
7. In a system for determining variations in the radial deflection of a cylindrical shell during its rotation upon supporting rollers, for assessment of conditions affecting the refractory lining within the shell the method comprising the step of securing a deflection sensor in spaced relation from a surface portion of the shell; actuating the deflection sensor during rotation of the shell, to monitor variations in the distance of the surface of the shell from the sensor, and recording variations during said rotation.
8. The method as set forth in claim 7 wherein said distance variations are recorded on a basis of lapsed time, during rotation of said shell.
9. The method as set forth in claim 8, wherein said distance variations are recorded at selected time intervals.
10. The method as set froth in claim 8, wherein the interior of said shell is heated, in operation.
11. The method as set forth in claim 8, including the step of plotting said radial deflections in relation to the rotation of said cylinder.
12. The method as set forth in claim 11, wherein said deflection sensor is successively repositioned along the length of said shell in positioned relation closely adjacent supporting tires of said shell, to obtain data accurately indicative of the extent of ovality developed by said shell, along the length thereof.
13. The method as set forth in claim 7, including taking readings of said variations at 360° succeeding rotational increments, to identify thermally induced variations in said readings due to changes in the temperature of attachment means securing said deflection sensor in spaced relation from said shell.
14. The method as set forth in claim 13, including correcting said variations, in accordance with said thermally induced variations.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA 2028505 CA2028505A1 (en) | 1990-10-25 | 1990-10-25 | Hollow shell deflection reading system |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA 2028505 CA2028505A1 (en) | 1990-10-25 | 1990-10-25 | Hollow shell deflection reading system |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA2028505A1 true CA2028505A1 (en) | 1992-04-26 |
Family
ID=4146253
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA 2028505 Abandoned CA2028505A1 (en) | 1990-10-25 | 1990-10-25 | Hollow shell deflection reading system |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA2028505A1 (en) |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2011058221A1 (en) * | 2009-11-11 | 2011-05-19 | Andritz Oy | Method for measuring and aligning a rotary cylindrical apparatus |
| CN105423880A (en) * | 2015-11-10 | 2016-03-23 | 长安大学 | Method for suspending main cable to measure bridge deflection |
| US9709332B1 (en) | 2016-03-09 | 2017-07-18 | Walter Gebhart | Self-aligning support system for a rotating body |
-
1990
- 1990-10-25 CA CA 2028505 patent/CA2028505A1/en not_active Abandoned
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2011058221A1 (en) * | 2009-11-11 | 2011-05-19 | Andritz Oy | Method for measuring and aligning a rotary cylindrical apparatus |
| US9234737B2 (en) | 2009-11-11 | 2016-01-12 | Andritz Oy | Method for measuring and aligning a rotary cylindrical apparatus |
| CN105423880A (en) * | 2015-11-10 | 2016-03-23 | 长安大学 | Method for suspending main cable to measure bridge deflection |
| CN105423880B (en) * | 2015-11-10 | 2017-11-24 | 长安大学 | A kind of method for hanging main push-towing rope measurement deflection of bridge span |
| US9709332B1 (en) | 2016-03-09 | 2017-07-18 | Walter Gebhart | Self-aligning support system for a rotating body |
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