on Maintenance Reliability

Orifice plate meter flow measurement. An orifice meter is a circular piece of metal plate placed between flanges in a pipe. In it is a square-edged round hole machined 0.5 to 0.8 pipe diameter in size. Pressure tapping points are placed either side of the plate at specified distances. The orifice causes a flow restriction and produces a pressure drop from one side of the hole to the other. The amount of pressure difference is proportional to the flow of fluid through the hole. The flow is calculated from the pressure difference and flow areas using accurate mathematical formulas. [Read more…]

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It’s important when resolving a problem that you address the problem and not a symptom of the problem. Determining the real problem is called finding the root cause. There are special techniques for determining the root cause of a problem. One technique is known as “The 5 Whys.” [Read more…]

Roller bearing vibration measurement is one of the major condition monitoring tools in regular use. By measuring the velocity, acceleration and frequencies emitted from a rolling bearing it is possible to tell its condition and the likelihood of imminent failure. The technology is well established and well proven but requires a good understanding of equipment vibration characteristics before a user can draw good interpretations from the results.

Keywords: out of balance, vibration analysis, bearing life [Read more…]

Dust control concepts. Industrial dust is the result of material escaping from the confines of a process or a storage location. The size of the problem depends on the dust’s characteristics and the means of its distribution. The best policy to control dust is to not let it escape from where it ought to belong. There are simple techniques that can be used to manage dust and prevent it from becoming a major health and environmental problem once the mechanism of creation and distribution are under stood. [Read more…]

Non-destructive testing of welds. Welding processes and methods can introduce contaminants and metallurgical defects into the weld. If a weld is required to withstand severe loading conditions and stresses it is critical to insure its quality meets minimum standards. Welds can be tested by destructive and non-destructive techniques. Most production is tested by use of non-destructive methods. The most common non-destructive tests to check welds are Visual Inspection, Liquid Penetrant, Magnetic Particle, Eddy Current, Ultrasonic, Acoustic Emission and Radiography. Keywords: NDT, quality control, non-conformance, verification, weld procedure. [Read more…]

Electric motor variable speed drives operation. Alternating current electric motor speeds can be changed by the use of a frequency converter. This device changes the frequency of the alternating current to the motor. This then changes the rotating speed of the motor’s internal magnetic field. The speed of the rotor responds accordingly and so allows for variable speed control of connected items. When these devices are used there are several issues that need to be addressed to insure successful selection and long-term operation. Keywords: VSD, precise speed control, over- speed, motor controller, frequency inverter. [Read more…]