Plant Maintenance

There is always a degree of uncertainty in selecting instrumentation for difficult or corrosive environments. Material selection for chemical compatibility involves a strained decision between cost and equipment reliability and longevity. The other major uncertainty is whether the instrument is appropriate for the application – will it repeatedly give truly representative readings all it’s operating life? This article presents a list of instrumentation successfully used in a range of difficult and chemically demanding environments.

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The cyclo-drive gearbox is a variation of a planetary gearbox. They have the added advantage of not using gear teeth to drive the shafts; rather they use an internal offset cam arrangement to drive rolling pins that turn a cycloidal wheel inside the gearbox. The rollers are capable of taking 500% overload without breaking the gearbox. One other benefit of the cyclo-drive gearbox for users is that many models are grease filled and do not use oil.

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Acid Sparge And Acid Sparging. When you want to introduce acid directly into a liquid below its surface a sparge pipe is used. It is necessary to select materials that are compatible with the chemicals and the process. This article explains the issues to address when selecting the sparge pipe materials for injecting acid into a process reactor and what to consider when designing and installing the sparge pipe into such vessels or tanks.

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Air Mover And Air Amplifier problems! Touted as great maintenance savers and a very efficient means of moving large volumes of air, they can in fact be extremely energy hungry. Based on using a small amount of compressed air to draw through a large amount of entrained air they can cause huge energy waste if an air compressor is run in order for the air mover to operate. It is wasteful to install an air mover on a plant air system unless the air compressor is always running well under peak demand.

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Budgets represent plans or expectations for the future! They are a means to plan, forecast, coordinate and control the activities needed to achieve the business’ objectives. The budget document contains the amount of money that has been allocated to achieve those goals and the timing of its spending. Budgets cover the planned use of men, materials, external resources and management effort that is expected to be sufficient to hit the targets. Once the budget is finalised it becomes a tool to feedback how the actual progress is going compared to what was expected. [Read more…]

Tracking belts on bucket elevators and short belt conveyors. Flexible, flat belts are used on bucket elevators and belt conveyors to carry loose, bulk product. The belt is stretched tight from head drum to tail drum and the friction generated on the turning head drum is used to drive the belt and carry the product. The belt must run true on the end pulleys (drums) and stay within the sides of the equipment structure. If the belt runs off the drums, buckets will be destroyed and belt edges frayed. In the worst cases the belt runs off the pulleys resulting in a breakdown repair. Proper and long- lived tracking of belts is critical for trouble-free operation. [Read more…]

Bag house dust bag selection. The dust bags within a bag house must handle the process conditions they experience. The choice of bag materials is usually based on the cheapest fabric that will handle the conditions for a minimum of 3 to 5 years’ operation. The selection of the bag materials requires a good understanding of the process temperature, moisture content, chemical reactions with the bag fibre, dust loading effects and behaviour of the dust bags in operation. [Read more…]

One method to clean particles from a liquid or gas is to pass it through a filter. The filter is a screen that traps and holds the contaminants on its surface while allowing the fluid to twist its way past the build-up and screen. The screen can be used until the back- pressure from the collected contaminants choke it so severely that the fluid flow falls drastically. At that point the screen must be cleaned. This article explains how membrane and leaf filtration processes work and the critical factors that produce successful filtration results. [Read more…]

In some process situations, mechanical level sensors are the best choice for the environment or are stipulated by law (as in boilers). To operate these devices requires the physical contact of the process being measured. They provide solid indisputable proof that a process condition has been achieved. Provided the mechanical mechanism is connected and working properly, these devices provide the most believable proof that a level in a vessel, tank or silo is actually what the instrument is saying it is. [Read more…]

A computerised maintenance management system (CMMS) is the maintenance department’s most important tool. It provides insight into the behaviour of the facility’s individual assets, i.e. the plant and equipment. For a CMMS to be of use it must be used as an information ‘bank’ that can be investigated. There are 9 really good reasons to use a CMMS. And each one of them alone makes a CMMS worth having. [Read more…]

When oil in gearboxes become contaminated there is a rapid loss of bearing operating life. It is critical that metal particles, dirt, sand, oxidisation products, etc be removed from the oil before they gouge and tear-up the finely toleranced machine parts. Oil replacement, contamination prevention and oil filtration are common practices religiously adopted by the best in the equipment reliability management business. This article explains the fine requirements for successful contamination control to insure long trouble- free equipment life. [Read more…]

Steam boilers not used for power generation and of smaller size and energy output are termed packaged boilers. The heat source is usually either electric coils or a burning fuel. When a flame is used to heat the water it is known as a fired packaged boiler. Fired boilers are considered efficient steam generators with about 85% of the available energy converted to steam. They can be of water-tube or fire-tube design. Boilers incorporate many key aspects of heat transfer to create steam from water. This article describes how fired boilers work and their key components. [Read more…]

Heat is energy and its nature is to flow from a state of high excitement to one of low excitement. Heat is transferred from a hot place to a cold place by convection, conduction or radiation. This article explains the three modes of heat transfer and provides simple examples of each. Methods to reduce and increase heat transfer are also presented. [Read more…]

The electrical conductivity (and its opposite, resistivity) of water based solutions indicate its electrical current carrying ability. High conductivity occurs when many charged atoms and ions are in the water. This typically means the presence of dissolved metals, salts, acidic or alkali chemicals. Conductivity probes are used to measure the total level of charged particles present. This article explains how conductivity probes work and their application in boiler water treatment and management. [Read more…]

A spinning pump impeller provides the means to draw incoming product through the pump, energise it, and then force it out under pressure. The impeller coverts the electrical energy from the motor into hydraulic energy of the liquid. It does this by taking the liquid into the center of the impeller and flinging it outward at high speed. To efficiently continue to do this the impeller must remain in the same condition as it was when first installed. If the impeller deteriorates the conversion from electrical to hydraulic energy becomes inefficient. Power is wasted, flow and pressure fall and the pump cannot do its designed duty. [Read more…]