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Permanent Inspection of Your Rotary Kiln

Basing on many years of experience in the field of rotary drum inspections - in particular of cement kilns, ZMP engineers have developed a system of permanent supervision of key parameters of this type of objects.
The main assumptions for the system were: simplicity of its operation on the user's side as well as innovation and advancement of the analytical and diagnostic tools implemented in it, operating in the background, completely independent of the will of the user.
As a result, a product was created, including software that is adapted for use on smartphones, thanks to which the user is immediately informed (via SMS message) about significant irregularities and / or anomalies in the mechanical conditions of the rotary drum, and after starting the mobile application user can view selected details, limited only to highly processed and valuable information, so that he can take an immediate and proper reaction.

the genesis of the idea

Periodical inspections of rotary drums in order to assess their mechanical condition are performed with consistency dependant on the importance of role that these objects are taking in the production chain and depending on the pace of anticipated wear of their components, but usually not more often than every few months, and in some extreme cases - even only every few years. Such a frequency gives the opportunity to assess the condition of an object at a precisely defined point on the time axis and for strictly defined operating conditions. However, it does not give the possibility of continuous evaluation, considering the changes of production conditions. Therefore, it also does not give, what is equally important, the possibility of unequivocally genesis the causes and the moment of occurrence of potential damages.
This limitation in the inference back, i.e. the inability to capture a specific point in time, in which the given defect was initiated, is a basic drawback of periodic diagnostics, carried out sporadically and constitutes a significant disadvantage in relation to continuous monitoring.
A kind of a substitute for continuous mechanical monitoring of rotary drum condition are, more and more often used on rotary kilns systems for scanning the shell temperature, or systems used for continuous measurement of migration of live rings. In the first case, however, we do not get any valuable feedback on the influence of the current temperature distribution of the shell on the operation of the key mechanical elements of the kiln. We do not know what value reaches the crank of the geometric axis of the kiln coming from the temperature disturbances and what consequences it results in terms of both the load on the shell and the load on the components of the support system (live rings, support rollers). We also do not have the view of the impact of possible uneven temperature distribution on the perimeter of the shell on the load of the drive section components. Their effectiveness is therefore limited to the assessment of the internal lining condition and indirect assessment of the quality of the production process.
In the case of migration measurement - very often it is not related to the difference between the temperature of the shell and the temperature of the live ring. Stresses in the material of the shell are also not calculated, i.e. effects associated with excessive migration (excessive under ring clearance - ovalization) or lack of migration (interference). Such a measuring system records only the lack of clearance (interference), but it does not inform the user what kind of stresses the pressure causes. It is also known that in the case of ring jam on the shell the stress in the material of the shell usually exceeds the value of few hundreds of MPa and cause immediate and permanent deformation, or even degradation, in this they are one of the additional sources of damage to the internal lining.
This gives the market view on which we have a choice or the possibility of using very advanced and comprehensive methods for mechanical evaluation of the drum condition, which due to high costs are realized only individually and by specialized companies – in a strictly defined period, or relatively basic information systems - monitoring only selected, basic parameters of the object, mainly those related to the production process, less often those related to the area of mechanics, in addition without analysis of their mutual correlation.
This gap and competences of ZMP became a catalyst for the development of a system that combines the principle of continuous monitoring of selected parameters of the object with their simultaneous processing for the information relevant to the mechanics, and thus from the point of view of strength of individual components of the machine, where the obtained values, especially stresses, unambiguously compare with the limit values - acceptable for the used material.

construction and operating principle of the system

The system is built of modules:
  • control unit (quantity = 1), which supervises the rotational speed of the object, initiates measurements in the remaining modules, controls the correct operation of these modules, collects data from all modules and sends them to the data server (to ZMP),
  • measuring type PIER (quantity = number of supports of the drum), which collects "on request" of the control module data from sensors located on a given support, where as standard supervised are:
    - circumferential migration of the ring in relation to the shell (indirectly under ring clearance),
    - dynamic deflection of support rollers shafts (indirectly so-called hidden component of shell geometrical axis),
    - axial run out of live ring (indirectly its wobbling and axial expansion of the kiln shell),
    - axial positions of support rollers (indirectly directions of axial impact of the support rollers on the object),
    - shell temperature (average value and circumferential distribution),
    - temperature of live ring,
    - temperatures of support rollers bearings (by direct or indirect measurement),
  • measuring type GR (quantity = 1), which collects "on-request" from the control module, data from sensors located on the drive section, where supervised are:
    - radial run out of the gear rim (indirectly the variability of the meshing clearance with the pinion),
    - axial run out of the gear rim (indirectly its wobbling and axial position in relation to the pinion),
    - vibrations of selected bearings (values like: RMS and peak and selected harmonic components).
Data (measured by the measuring modules) are transferred and collected in the control unit. There, a software with sophisticated analytical algorithms makes them further processed and as a result, we get:
  • stresses in the shell,
  • stresses in the rollers’ shafts
  • stresses in the rings,
  • Hertz’ stresses in the contact area of the rings’ and rollers’ raceways, in each case distinguishing the source, which may be:
    - nominal load,
    - crank of the shell geometric axis,
    - ovalization of the cross-section, depending on the under-ring clearance (concerns only stresses in the shell).
These stresses are compared on a regular basis with the permissible values for the used materials and in case of exceeding these limits, the system generates relevant messages.
The system also calculates:
  • under ring clearance, and in the case of a lack of clearance, estimates the pressure and stress value associated with this interference,
  • dynamic deflections of support rollers shafts,
  • crank value of shell geometrical axis (hidden component of eccentricity) and the values of forces from additional loads generated by this crank,
  • wobbling of the live rings and gear rim.
The values of these parameters are also compared to the permissible values, where they are calculated mainly from strength dependencies. Limit values and general principles adopted for their determination are given in the User's Manual (provided with the system), and the details of the system and its components as well as the analytical application are presented as part of the training accompanying the system implementation process for a given facility.

types of messages

The system is equipped with two mutually complementary ways of notifying the user about the occurrence of exceeding the limit values:
  • SMS messages,
  • graphic messages generated in the application (directly on your smartphone).
SMS messages are sent to a strictly declared group of users (persons indicated as interested in the condition of the kiln), and the system distinguishes between two types of notifications:
  • warning / alert SMS – this is an information about exceeding the warning or critical level set by the system for a given supervised parameter,
  • custom SMS – this is an information about exceeding the level for a given parameter, the level being set by the user himself.
Graphic messages are designed to make it easier for users to find in the application (on the smartphone) the parameters and moments in time when these exceedances occurred.
Thanks to the link sent directly in the SMS message, you can quickly go to a mobile application which, after user identification, gives the possibility of a more detailed view of the numerical values of all key, supervised and calculated parameters, including viewing their limits.
The supervised values (measured - calculated) are arranged in columns corresponding to the subsequent supports of the kiln and are placed in colored frames, where the background and frame color mean respectively:
  • white background / green frame – no objections to the current value of a given parameter;
  • white background / orange frame – exceeding the level of warning alert for the current value of a given parameter;
  • white background / red frame – exceeding the level of critical alert for the current value of a given parameter.
In the case of summary (total) stresses calculated for the shell, rollers and rings, due to the superior importance of this factor, in addition to changing the color of the frame, the background color also changes.
After clicking on a given frame with a numerical value of any parameter, the user has the opportunity to review historical data in the form of daily, monthly or yearly charts, in all cases against the background of limit values.
The speed curve is also displayed on each graph (black line at the top).
Charts on a daily basis are enriched with additional symbols - message bubbles indicating the moment the system generates (sends) an SMS message (warning or alert level).
The user, by changing the system settings, but only on his individual user profile, has the option to stop the emission of SMS messages. This fact is noted by the system software.

system benefits, advantages of implementation

  • immediate information about the risk of damage to individual components of the supervised object;
  • access to data showing the current mechanical condition of the kiln from anywhere in the world, using a smartphone or any other device equipped with a web browser;
  • data security thanks to identification of individual users and their profile settings;
  • simplicity of application and legibility of displayed information on the user's side;
  • automation of measurements and their integration with sophisticated analytical methods, including strength calculations (currently the most advanced and specialized system for diagnostics of multi-support rotary drums from the point of view of their mechanics);
  • elimination of the costs of maintaining your own specialized diagnostics team and reducing the costs of hiring specialized external companies while ensuring continuous and substantive monitoring of the facility;
  • relatively low implementation and maintenance costs, with the option of system implementation in several stages;
  • the possibility of rational management of spare parts and consumables, as a result of observing trends of individual parameters of the drum, affecting the durability of its components;
  • a fuller understanding of the pace and causes of degradation processes (wear, disregulation of the system, etc.);
  • a fuller understanding of the relationship between individual object parameters and its mechanical state (correlation trend analysis).


  • large-size, multi-support (number of live rings three and more) rotary kilns (typical application);
  • other rotary drums, including 2-support objects (solution requiring individual selection of the range of monitored and calculated parameters);

implementation stages

  • comprehensive audit of the facility in the scope of the support system, shell and drive section, including the implementation of the necessary basic strength analyzes, to:
    - determine the object state,
    - set the strength limits for its individual components,
    - determine adjustment and / or repair actions suggested to implement before the installation of the system,
  • preparation and submission of a final price offer for agreed technical conditions of system implementation;
  • implementation of the system including:
    - installation and calibration of measuring sensors,
    - adaptation of software for the needs of a given facility,
    - startup of the system,
    - training of the Clients personnel in scope of:
    - using the system, interpreting the results,
    - correctly operate and maintain the system,
    - service and substantive support (to the extent agreed in the contract);
  • post-warranty service (on terms agreed in the contract).
Due to the policy of intellectual property protection, the above content has been limited to a necessary minimum. More detailed information on the principles of operation and implementation of DrSmart are shown during a direct or remote presentation. If you are interested in the system, please contact us to schedule a meeting.

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