Advanced technology: use "two-meter method" to accurately detect the end face runout of the big gear ring

(I) Introduction: Big gear ring is the key

to the stable operation of rotary kiln. Rotary kiln is the core equipment of cement, building materials, metallurgy, chemical industry and other industries. It has the characteristics of large size, heavy operation load and other characteristics, coupled with the impact of thermal conditions in the production process. Many factors, such as the shape and position relationship between the components, the mutual force and the temperature change, are superimposed and interfered with each other, which affects and destroys the stable operation of the rotary kiln. According to the different functional characteristics of each component, the rotary kiln can be divided into the following parts:

support system: the main components are supporting wheel group and wheel belt; its core function is to support the rotary kiln (to maintain the roundness of the kiln cylinder) and position (to maintain the correct straightness of the rotary kiln);

Drive system: the main components are big gear ring, pinion, reducer, etc.; the core function is to provide stable rotation driving force;

Axial force balance: the main component is the hydraulic catch wheel system, whose core function is to maintain the balance of the overall axial force of the rotary kiln, so that the kiln shell can move up and down periodically, so as to ensure the reasonable change range of the working parts of the driving components and supporting components;

Kiln shell: keep reasonable mechanical dimensions (thickness, straightness, roundness, etc.) and mechanical properties (pay attention to the thickness wear of the shell, fatigue crack of the weld, etc.).

As far as the driving system is concerned, whether the overall installation quality is good or not is directly related to the stability and reliability of the rotary kiln operation; the big gear ring is the key component in the driving system, which has large overall dimensions, heavy single weight and high manufacturing precision (material, heat treatment, processing precision, etc.); In addition, whether the initial installation accuracy of the big gear ring and the kiln shell is good (the coaxiality and perpendicularity of the big gear ring and the shell) is the basic factor for the overall installation quality of the subsequent pinion alignment and positioning, reducer and other driving systems.

Under normal circumstances, the general method for end face runout (end face runout for short) detection is to set up a dial indicator so that its pointer points vertically to the end face of the big gear ring. Use the slow drive device to rotate the kiln body for one circle and read the readings of the dial indicator at the average points of each circle (generally 8 or 12 points), and then carry out the subsequent calculation. It should be noted that during the rotation of the rotary kiln (no matter what driving mode is adopted), due to the interaction force generated by the dynamic contact among the kiln body (base plate, iron block), wheel belt and supporting wheel, the rotary kiln will inevitably produce unpredictable slight (millimeter-level) upward (high-end) or downward (low-end) axial displacement. This tiny displacement value is directly mixed into the reading of the end-jump dial indicator, resulting in serious distortion of the measurement results.

(3) Solution: Two-table Method-Accurate Elimination of Axial Interference

Are there any measures to eliminate this "inevitable" and "unpredictable" interference factor? ccement.com/news/2601/richtext/img/697089054d7f11315318.png">

(3) slowly drive the rotary kiln for one cycle, read and record the values of the two meters at each point.". Note that the and B tables should be read at the same time, and the data should be recorded in the following table.

(4) Calculate the algebraic difference between Table A and Table B. Note the position correspondence, A1-B7, A2-B8..

The key point is to calculate the algebraic difference in step (4) above, which is the key to the logic of the "two-table method":

① The end face runout of the corresponding point of the diameter of the large gear ring presents "reverse symmetry", which is a basic feature of the large gear ring;

② During the whole measurement process of one rotation of the rotary kiln, whenever the rotary kiln has a slight axial movement to the high end or the low end, the amount of movement is recorded in Table A and Table B at the same time, and is cleared when the "algebraic difference" is calculated.

Therefore, the end face runout measured by the two-gauge method is an accurate value that completely excludes the axial movement of the kiln body.

in the industry that is more convenient, The efficient operation method is evolved from the classical two-table method, but it avoids the suspension operation on site. A brief description is as follows:

(3) Calculate the algebraic difference (d) of the corresponding values in Table A and Table B, i.e., D1 = A1-B2, D2 = A2-B3.. where S/n is the average of the measurement errors.

(4) Conclusion and Practical Popularization

" Two-table Method "through ingenious layout design And the interference problem of the axial movement of the rotary kiln on the end face runout measurement is fundamentally solved. Although more preparation work is needed in operation, the accuracy of the data provided by the method is incomparable to that of the traditional single table method, and the method is a key technical means for ensuring the installation accuracy of the big gear ring, improving the installation qualification rate and the working efficiency, and ensuring the long-term stable operation of the rotary kiln. It is suggested that it should be seriously popularized and used in equipment installation and important maintenance projects.

Based on the above logical principle (method 2), Tangshan Youdu Science and Technology Co., Ltd. Its practical advantages are as follows:

1) when the high-precision eddy current sensor (repeatability 0.3

) is used for detection, the sensor probe is close to but not in contact with the big gear ring (spacing is about 5mm), so it is not affected by the oil stain on the surface, the kiln can be rotated continuously during measurement, and the traditional method of "stopping the kiln and checking the meter" at each point is not needed. The operation process is safe and convenient, and the measurement result is accurate and efficient. Under normal circumstances, the detection of end face runout can be completed by one slow drive of rotary kiln, and the operation time can be shortened by at least three times.

4) The software system of the instrument integrates the data acquisition, screening, analysis, calculation and adjustment suggestions (including the adjusted point position and the corresponding data) of the above steps, which reduces the error of manual operation and calculation to the greatest extent and significantly improves the detection efficiency. The company is willing to provide special technical services or testing instruments for relevant production enterprises and professional maintenance units.