13-09-2014, 10:57 AM
TROUBLESHOOTING OF ROTATING EQUIPMENTS THROUGH VIBRATION ANALYSIS
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ABSTRACT
The success of a company often depends on the safe, continued production by its machinery. Here occurs the importance of predictive maintenance. Predictive maintenance is the process of forecasting the errors in the machinery by inspecting the condition of the machine condition. Vibration analysis technique is the most important condition technique applied in real life. It is done by checking the machine vibration characteristics like displacement, acceleration, frequency, and spike-energy. The impedance troubles that may occur can be traced by analyzing the vibration characteristics. This will provide timely maintenance and prevent huge production loss and sudden shut down. In this project the condition of ball mill and attack scrubber fan at the PA plant at FACT COCHIN DIVISION are checked.
INTRODUCTION
The use of machinery vibration and technology advances that have been developed over the year makes it possible not only to detect when a machine is developing a problem, but to identify its specific nature of problem for the scheduled correction. When a machine fails or breakdown, the consequences can range from annoyance to financial distortion or personal injury and possibly loss of life. Thus vibration analysis is of great importance and it not only minimizes the need of extensive experience, but also makes it possible to detect the developing problems which are outside the range of human senses to touch and hearing. Here the introduction of vibration analysis and outline a simple, logical and systematic approach that has been proved successful in pinpointing the vast majority of most common day to day machine problems is done.
The vibration analysis we have done is a part of conditional monitoring techniques and it's mainly used for the improved performance of equipments. Using this we can predict the condition of the internal parts of the equipments. Thus this is a type of predictive maintenance techniques. We are mainly dealing with the vibration analysis on rotary equipments. It includes typical causes of vibration like misalignment of shafts, looseness, bearing faults, unbalance, oil fracture etc.
This project explains the vibration analysis, methodology, readings, and case studies of ball mill motor and scrubber fan motor
COMPANY PROFILE
The fertilizer industry has played a significant role in the development of agriculture in India. Majority of the rural population in India still depend on agriculture for their livelihood and agriculture and allied activities contribute about 30% of GDP of India, Growth and development of agriculture in India derives a significant stimulus from the fertilizer industry. Development and growth of this vital industry is crucial for the sustainable growth of agriculture and to ensure food security of the nation.
The Second World War which cut off traditional sources of import load grain, aggravated our problem and the famine condition that prevailed in some parts of the country made us sit and think. Chemical fertilizer was the answer, but we did not have technical know, raw materials or resources for setting up fertilizer plants. It was the a daring and far sighted administrator of Travancore (Kerala) Dr. C.P.RamaswamyIyer, had overcome the obstacles and paved the way for setting up chemical fertilizer factory, in a till then unheard village in Kerala with what little that was available and then adopting technology and raw materials that could be mustered up. The immediate objective was to grow more food using wonder replenished, chemical fertilizers. This is how F.A.C.T came to be founded in what is known as Udyogamandal, on the banks of river Periyar in 1944. It was then the first large scale factory in the entire country
The Fertilisers and Chemicals Travancore Limited (FACT) was incorporated in 1943. In 1947 FACT started production of Ammonium Sulphate with an installed capacity of 10,000 MT per annum at Udyogamandal, near Cochin. In the year 1960, FACT became a PSU and towards the end of 1962, Government of India became the major shareholder.
FACT has the widest range of fertilizers which is made available to the farmers spread over a wide area covering the entire south, straight fertilizers like Ammonium sulphate, Urea, MOP, and also complex fertilizers like Factomos 20-20-0-13. FACT produces NPK mixtures to suit all crops and all soils. FACT also manufactures various grades of bio-fertilizers.
From a modest beginning, FACT has grown and diversified into a multi-division/multi-function Organisation with basic interest in manufacture and marketing of Fertilisers and Petrochemicals, Engineering Consultancy and Design and in Fabrication and Erection of Industrial Equipments.
CONDITION MONITORING AND VIBRATION ANALYSIS
Condition monitoring is the activity of maintenance for monitoring the condition of the internals of any running equipment without disrupting the operation. The monitoring is done by collection of data of various parameters like rpm, operating temperature, lubrication condition, nature, noise and vibration level, power consumption level etc. Condition monitoring makes use of advanced technologies in order to determine equipment condition and potentially predict failure. It includes, but is not limited to technologies such as,
Vibration Measurement and Analysis
Infrared Thermograph
Oil analysis
Ultrasonic
Motor current Analysis
Condition monitoring is most frequently used as a predictive or condition-based technique. However, there are other predictive maintenance techniques that can also be used including the use of the human senses (look, listen, feel, smell etc), Machine performance monitoring and statically process control techniques.
The need that dominates the industrial maintenance scenes is asset effectiveness- the need to extract maximum profits from the minimum investment in plant and equipment. We achieve this through the use of condition monitoring technologies in the following ways:
By improving equipment reliability through the effective prediction (and then avoidance) of equipment failures.
By minimizing downtime through the integrated planning and scheduling of repairs indicated by other techniques.
By maximizing component life by avoiding the conditions that reduce equipment life.
By utilizing condition monitoring techniques to maximize equipment performance and throughput.
By minimizing condition monitoring costs.
VIBRATION MONITORING
Since the mid 1950's the measurement and analyses of vibration has become an increasing technique for monitoring machinery condition. All machines will have some vibration because of minor defects or result manufacturing tolerances. Therefore all machines have tolerance of vibration, which may be regarded as normal or inherent. When machinery vibration increases or become excessive, some mechanical trouble is usually the reason, the cause be unbalance worn gears or bearings looseness. Etc, each mechanical defect generates vibration is in its unique way. This makes it possible to identify a mechanical problem by simply measuring and noting its vibration characteristics. A good vibration analysis program makes it possible to detect an impending problem, analyze it cause and take appropriate correction action before the failure occurs.
Vibration due to oil whirl
Oil whirl is a condition peculiar to journal bearing. It manifests itself as a vibration of less than one-half of rotational speed. It is caused by a lightly loaded bearing riding up on its high-pressure wedge and going "up over the top and around". The journal is actually revolving inside its bearing in the opposite direction of rotation at about 45 percent of the rotating speed, comes from the average fluid velocity with some slippage.
When oil whirl become severe, there is a potential for the shaft to rub inside of the journal. This causes friction and subsequent localized heating. A rub is a symptom and can be caused by other factors, most notably by heavy imbalance or severe misalignment. The rub is a metal to metal contact and as such, shows best in the time domain. In frequency domain it is no clear. The most notable effect of rubbing is a localized temperature rise followed by metal particles in the oil. Both of these should be used as a supporting evidence to confirm a suspected rub. The analysis of rubbing based on vibration spectral data is not defined well enough to analyze this condition with confidence. The best indicator, in terms of vibrations, is an increase in the overall vibration level followed by observing the time domain view for evidence of metal-to- metal contact.
CONCLUSION
After completion of the project we have concluded that the benefit of Trouble Shooting through vibration analysis is as follows;
• It gives information about the changing condition of the equipment. Thus enabling the avoidance of total breakdown and reduced down time.
• Prediction of residual life enables the equipment to be stopped before they reach critical condition. Thus safe operation is ensured.
• Increased machine availability and utilization give greater output, face-lifting & higher returns on investment
• Improved production quality is achieved through conditioned monitoring and operation of equipment.
• Determination of the realistic delivery time based on actual condition of the plant improves customer relationship by minimizing unpredicted breakdown.
• Detection of the incipient fault and determination of plant condition enables forecasting maintenance demand.