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This Plant Maintenance articles series relates to doing maintenance and care on operating plant and equipment. It includes coverage of maintenance engineering issues, and topics on the maintenance of process plant operating assets and industrial equipment.
The Plant Maintenance series of articles are provided with the permission of Feed Forward Publications and Lifetime Reliability Solutions.
NOTE: The series does not include coverage of related commercial or vendor software or database management applications.
Plant compressed air waste control. Every compressed air system will eventually develop leaks from connectors and redundant pipelines. Compressed air is very expensive to make. It is necessary to institute regular inspections for air leaks and fix them immediately.
Keywords: pressure loss, energy loss, air compressor, pressure switch. [Read more…]
Metering and dosing pump operation. Any positive displacement pump can be used as a metering or dosing pump. The purpose of these pumps is to inject a known volume of liquid into a process stream. The primary requirement is that over a given period of time the pump consistently delivers the same amount of liquid. Keyword: gear pump, piston pump, helical rotor pump, diaphragm pump, peristaltic (hose) pump, additive, dosing rate. [Read more…]
Is your scrubbing tower working? A wet scrubbing tower is used to clean odors, particles, mists and vapours from a gas stream. The gas is forced through the tower. As it moves from inlet to outlet it is washed and cleaned. The washing is done with suitable chemicals that remove the active components in the gas flow. The gas is cleaned to environmentally acceptable levels and discharged to atmosphere. Keywords: packed tower, packing, fill, mist eliminator. [Read more…]
Flow meters – don’t believe what they tell you. A flow meter is an instrument that measures the amount of fluid (liquid or gas) that passes through it. The meter in the pipe is the detecting device and increases the count when a specific quantity of fluid passes by. There are several types of flow meters in common use. They include magnetic flow meters, vortex flow meters, mass flow meters, turbine flow meters, rotor blade meters, paddle flow meters, and ultrasonic flow meters. Usual the quoted accuracy on the flow meter specification sheet is for water at 20oC. However when the meter is installed in a process application it is unlikely that the meter will meet the quoted accuracy without site-specific calibration. Keywords: calibration, certified test equipment, flow meter accuracy.
The manufacturer performs laboratory trials of its equipment to insure the flow meter meets their claims for accuracy. Since the manufacturer does not know where their meter will be used they standardise the tests by using water at known conditions. Unless the meter is used in a situation identical to the laboratory conditions the given accuracy is unlikely to be achieved. [Read more…]
What you will learn from this article.
Some plastics can be joined with glues or cements. One of the most common of these is PVC. PVC can be either unplasticised (uPVC) or chlorinated (cPVC). Some plastics can be dissolved and chemically bonded together. ABS plastic is such a plastic. [Read more…]
What you will learn from this article.
What you will learn from this article.
Agitated vessels and tanks are common throughout the process and chemical industries. A properly sized agitator with correct proportions to suit the tank will deliver well-mixed product. A correctly sized gearbox with well-chosen bearings and bearing arrangements will need only regular lubrication while giving years of trouble free service. [Read more…]
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The sole purpose of using process control in, say, the making of beer, is to detect what is happening during manufacture and to decide if something needs to be changed to insure the beer meets the necessary specification. The key words are ‘to detect’, ‘to decide’, ‘to change’ and ‘to meet specification’. A control loop can do all these things automatically. [Read more…]
What you will learn from this article.
Root Cause Analysis is a step by step method that leads to the discovery of a fault’s first or root cause. Every equipment failure happens for a number of reasons. There is a definite progression of actions and consequences that lead to a failure. An RCA investigation traces the cause and effect trail from the end failure back to the root cause. Much like a detective solving a crime. [Read more…]
What you will learn from this article.
A tornado can lift cars from the ground and hurl them hundreds of meters away. Chickens and ducks can be hurled kilometers away. The story of fish falling from the sky is explained by the power of a tornado to lift materials kilometers into the sky. The spinning vortex of air separates and segregates heavy and light objects. The heavy objects drop out sooner and the light objects are carried further. Cyclone separators and hydrocyclones work the same way. [Read more…]
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Why don’t you fall to the ground when you sit in a chair? Why doesn’t the roof fall in on top of you? We don’t expect these sorts of things to happen. But at times chairs fail and people fall to the ground and at times roofs fall on people. When structures are put under sufficient stress they will fail. [Read more…]
What you will learn from this article.
What you will learn from this article.
Clean, dry oil can extend equipment life between failure up to 8 – 10 times the normal operating life. Timken, the bearing manufacturer, reports that reducing water levels from 100 ppm (parts per million) to 25 ppm increases bearing life 2 times. British hydraulics research indicates that if solids contamination with particles larger than 5 microns (0.005 mm or 0.0002”) is reduced from the range of 5,000 – 10,000 particles per milliliter of oil to 160 – 320 particles, the machine life is increased 5 times. [Read more…]
Abrasion is the removal of material from a surface by the movement of material across its surface. The factors affecting abrasive wear are the surface properties of the item being worn away, the abrasive properties of the material moving across the surface and the characteristics of motion. [Read more…]