Identification of mechanical problems and symptoms.
Bez kategorii / 20 stycznia 2017

All rotary kilns have many rotation surfaces working together that has to be set with high geometrical precision.  Any damage of working components will accelerate very fast if the geometry is not maintained properly. The alignment inspections of all components are a very good solution to find the problems before it starts. The maintenance routine should be performed regularly daily, weekly, monthly and yearly. Mechanical kiln inspection We can divide the kiln design to: 2-pier units and multiple pier units. The 2-pier is geometrically simpler solutions. It is composed with four big support rollers with shafts and bearing. All components are design to be as mechanically frictionless as possible. Also the load is evenly distributed to supports.  The multiple pier design means three or more supports. The design is quite the same but more components making more difficulties to maintenance work. Identification of mechanical problems is a very wide subject in this area. To provide continuous operation and costs effectiveness the alignment inspections are recommended. The rotary kiln mechanical condition largely depends on supports. Geometrical deviation, movement, settlement of supports has direct influence on the general operation of the working equipment and components. Kiln’s supports are normally design and made…

Misalignment
Bez kategorii / 20 stycznia 2017

When the support rollers are not in a correct geometrical position the rotating load is different for each pear, each roller. This condition has strong influence over kiln service life. Misalignment causes the same overloading stress condition like crank in the shell. The difference is that the bend of shell creates overload stress once per revolution of kiln, not correct position of kiln axis has a negative impact on a permanent basis. This geometrical situation can lead to many serious damages like cracks, refractory lining failure, hot bearings, under-tire shims cracks, rollers shaft damage, high amperage during operation. Deformation of kiln shell? always when the kiln shell is misaligned precise alignment measurement should be performed. The kiln shell misalignment is very difficult o detect visually in contrast to cracks or heat damage. Precise measurement are necessary. The first sign, symptom of axis deviation often can be a rise in amperage usage during operation. As even small deviation can lead to big damages alignment measurement and data obtained has to be very precise and reliable.  This kind of work is generally carried out by outside companies, sometimes by Cement Plant crew. When the user identify the shell geometry problem it is…

Damage caused by heat
Bez kategorii / 20 stycznia 2017

Rotary kiln shell tends to heat damage. The “hot spot” formation can appear every time when refractory fall at some part of shell segment. Sometimes it looks like red spot on shell surface. The size is from couple of centimeters up to much larger area. Also some other symptoms like blisters on the surface is a very important warning that should never be ignored. To monitor thermal distribution of kiln shell the Cement Plants crew generally use infrared thermal scanners. These equipment linked with advanced software allows to show both actual, real-time temperature and history data in order to perform analysis. Thermal scanner is a very important preventive maintenance tools that allows to detect potential cause of problems with klin shell deformation. With proper data analysis adequate steps can be taken long before kiln shell damage. The overheated part of shell is just the beginning of problems. After overheating the “hot spot” shrink and flatten. It may cause the bending of the shell or even shorten it. The most common extreme cases is “crank shaft” and “dog leg” formations. The overheated parts creates deviations in kiln shell. These, in turn causes other problems. At the area where the hot spot…

Kiln Alignment – Preventative Maintenance Strategy.
Bez kategorii / 20 stycznia 2017

Based on our experience we can distinguish six different concepts of rotary kiln maintenance. Aligning and inspecting the kiln with these knowledge the user can ensure long time of operation – unexpected stoppages reduced to minimum.  Ignoring these 6 issues equals more damages of rotary equipment. The components like support rollers are very often ignored by the users of rotary kiln. It is not possible to operate kiln without taking care of rollers and its foundations. Many people look differently to rotary equipment then housing, base plates or concrete support around. But truth is the solid supports is the key of maintenance-free operation. With a poor foundation the kiln failure will appear very quickly. Rotary kiln alignment The rotary kilns are design to work for a very long time. Because rotation speed is quite slow all components needs some time to get damage, but want to ensure long service life of rotary kiln most of all the user has to take care of proper geometry of components. First and a very important parameter is a base slope. If it is not correct can wear taper shape of rollers and tires. Irregular surface shape cause incorrect axial kiln balance or at…

Hot Kiln Alignment – the most important part of preventative maintenance.
Bez kategorii / 20 stycznia 2017

Alignment measurement taken during normal rotary kiln operation (hot kiln alignment) became industry standard these days. There are many different type of services and different methods of alignment/measurement available. Some of them use the movement of the machinery as an advantage other treat kiln’s operation as an obstacle. From maintenance point of view alignment starts with the kiln erection. None of the manufacturers (vendors) does not provide any support with regard to the correct geometry and alignment of the kiln after installation. The Customer must take care of it by yourself. Have to monitor kiln condition all the time. All deviation, misalignment  caused by installation work or operating conditions can shorten the life time of many components. Generally the Customer (Cement Plant) has a very short warranties time after kiln erection. A good solution in that case is to have an agreement with third party company for hot kiln alignment services after first few years of kiln operation. In that way it is possible to avoid excessive and premature wear. Also the geometrical and operation analysis can start at a very early stage. During erection the alignment is very often monitored internally. When the kiln in normal operation (hot condition)…

Rotary Kiln Shell Inspection
Bez kategorii / 20 stycznia 2017

Main rotary kiln inspection starts with the shell. Then it proceeds to each support, sealing and drive system (girth gear, pinion, coupling, gearbox, redactor, lubrication etc.). This basic (visual) inspection should be scheduled daily. All changes from previous control procedure should be recorded and analyzed by experienced diagnostician. Three main areas of stress that you should focus during kiln shell inspection is: cracks, thermal crank (shell temperature distribution) and other kiln shell problem caused by misalignment. Cracks The most serious sign of shell stress is crack appearance on steel shims area (chair pads). There are two kind of shell cracks: Longitudinal cracks – running parallel to kiln axis. It is usually a result of concentration of stress caused at a weld attachment. This kind of cracks are generally found in the shell close to under-tire shell segment and steel shims welded to the shell. The stress on that part is very high. When stress is getting higher (due to kiln geometry, axis, rollers skewing, inclination, higher amperage  etc.) all weld attachment should be inspected regularly.  Another cause of longitudinal cracks could be also excessive flexing of the shell. Circumferential cracks – generally appear close to circumferential weld connections (shell segments)…