Boilers are made in different designs and sizes. They are basically used in heating water to generate steam. Steam produced is then used for various functions, for instance power generation in energy business, drying, humidification, sterilization among others. Most steam locomotives use boilers. Some of the boilers developed include haystack boilers, fluid boilers and water tube boilers.
A tube steam boiler is the oldest and the basic type of boiler. In this boiler fuel is burnt inside a furnace. Hot gases pass from a furnace through a single or many fire tubes passing through a closed water container. Through thermal conduction, heat from these gases reaches the water surrounding the tubes. This results to heating, causing saturated steam to evolve from the water which naturally rises up. It is then collected in the steam dome. This steam is channeled through the steam outlet and gets superheated in order to dry the steam by heating it to superheated steam. Thereafter this steam is concentrated to cylinders of a steam engine. In some cases it is directed to turbines for generation of electricity through mechanical work. Water is served into the fire tube steam boiler via a water inlet. The exhaust gases can be disposed through a chimney or used to preheat the fed water. This is recommended in order to increase efficiency of the boiler.
The boiler is designed with distinct features making it more suitable and efficient. It has small tubes which offer larger surface area for heating, the tank is also made cylindrical since it is a strong practical shape for practical container. This boiler is self-pressure controlled since steam pressure in the drum raises boiling temperature of water reducing production of steam. Safety valves are used to release steam to avoid a lethal pressure which may build up. In addition to safety reasons, fusible plugs are placed over the firebox. These plugs melt at a lower temperature than that of firebox plates therefore alerting operators by the noisy escape of steam. Water tubes are installed in the boiler to increase the heating surface. A baffle of firebricks is fitted inside the firebox to direct flow of gases up in to the top of firebox before being allowed to flow into the fire tubes. This balances heat between the upper and lower fire tubes thereby increasing its efficiency.
Corrosion can be prevented by providing a physical link between the firebox and boiler. In this case ties are used to prevent the boiler casing from warping. The boiler can be maintained through regular or periodic inspection, general overhaul and washout of boiler components and parts. Excessive cycling which results to lose in efficiency should be minimized by use of condensing and non-condensing modulating boilers or by setting temperature controllers.
Industries make use of boilers in the running of their daily operations. This improves their effectiveness and reliability. Boilers play a vital role in generation of energy, drying, humidification and sterilization. This implies that they should be well maintained and safety measures taken to safeguard operators, environment and the external community from any danger that may arise from operation of the boilers. There are different boiler designs and modifications are made to suit the need and required standards of various industries.