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A proximity switch is the common name for a range of detectors that generate an electrical signal when a physical mass cuts through their sensor field. Upon detection of an object, the electrical signal is sent to a controlling device and is used to monitor and control the operation of the equipment.
The practice of maintenance has been developing for the past 300 years. Since the start of the Industrial Revolution machinery and their control systems have played a critical part in our ability to produce consumer and industrial goods. Over that time different maintenance philosophies have developed in response to changing technology and increasing costs.
The progression in philosophies started with breakdown maintenance (BM), then to time-based maintenance such as preventative maintenance (PM) and shutdown maintenance. More recently condition-based maintenance (CM) has become significant. The next step is predictive maintenance. [Read more…]
This article discusses the use of vee-belt drives. It covers some basic theory of friction drives and lists 11 factors to be considered when using vee-belt drives. [Read more…]
This article explains the metal corrosion process including the basic chemistry of how metal loss occurs. Methods to control corrosion are also listed and explained. [Read more…]
When a control valve or manual valve is shut fast in a full pipeline of moving liquid, the liquid comes to a sudden stop. If the pipe suddenly starts banging and thrashing about you can be sure a water hammer was created. [Read more…]
This true story could have been a lot worse. A NB100 (4”) flanged plug valve was removed from a 98% sulphuric acid tank nozzle and returned to the supplier. When the valve was opened for inspection at the supplier’s workshop acid was sprayed over the repairman’s legs.
If 98% sulphuric acid lands on skin it immediately boils out the moisture in the skin and burns it. A review of the incident was conducted to learn from the accident and to put corrective measures into place. [Read more…]
This article explains the operation of peristaltic (hose) pumps and gives twelve points to be aware of when using them. [Read more…]
This article presents a basic explanation of electric motor construction and operation along with eleven problems that can be encountered with their use.
Most electric motors in industrial equipment are three phase alternating current induction motors. Induction is the creation of an electric current across a gap. Two types of induction motors are commonly used: squirrel-cage and wound-rotor. The names come from the way they are built. [Read more…]
In this article on pulse jet bag house dust collectors we cover twelve factors spanning their design and operation.
A bag house dust collector is used to separate dust from a dust-contaminated gas stream. The gas is filtered through bags made of fabric. The fabric traps and filters out the dust while the cleaned gas passes through. The fabric consists of either woven or intertwined (felted) fibres. The bag fibre is selected for its ability to give a long working life within the internal environment of the dust collector. [Read more…]
If you are ever in the fortunate position of developing a maintenance system from the beginning, the list below will help you focus your efforts. Maintenance systems in small business, develop by default and without much forethought. This list puts together, in one place, the important components of a workable maintenance system. [Read more…]
Changing out dust bags in reverse pulse dust collectors. The dust bags in pulse jet dust collectors require replacement if damaged and leaking or if blinded by the product. This work procedure indicates the process and methods to use to change-out and replace dust bags and cages in a dust collector. Keywords: tube plate, bag collar, air manifold, air plenum.
This quarter we would talk a little about bronzes, their properties and applications. One of our readers said they occasionally hear people refer to a brass bush when in fact they want a bronze bush and could we write something on this. Lets also look at the range of materials one may come across:
This article covers the conversion of the shaft bearings on a basket centrifuge from oil-bath to grease lubrication. [Read more…]
The temperature of a process is an important measure to know as it indicates whether or not the process is in control.
The selection of the temperature sensing method depends on
The watch keeper of old guarded their people and possessions. They were found walking about looking, listening, and watching for changes that signaled danger. Their job was to look for hazards and quickly raise the alarm before all of them were invaded and killed or captured into slavery. With sufficient warning the home group could rally to the defence and counter-attack the enemy.
Times haven’t changed that much. Instead of being invaded by the enemy we now get consumed by plant and equipment problems. If only there was an effective way to spot problems coming our way and mount a counter-attack before being overrun. [Read more…]