Boiler is an important piece of machinery that is being on ship. It is used to generate steam and in turn this steam is used for various purposes like heating of fuel oil, laundry etc. Since Boiler is a pressurized vessel and it is needed all the time, proper functioning of this piece of equipment is always necessary. There are various mountings fitted on the sides of boiler, so that it can work properly and that too in a controlled manner. Boiler working is a nice topic to read and pdf boiler books are available in plenty In this article I have discussed about every mounting and discussed them in proper detail.
Safety Valves- They are two in number but can be three also, if the boiler has an super heater fitted inside it. This is a very important mountings fitted on the boiler and its proper function is prerequisite. If it is not maintained properly, its working is abysmally affected. Safety valve protects boiler from an uneven increase in pressure. It entails to be set up on a desired value that is safe enough and when pressure in boiler reaches to that level, it lifts up and releases the pressure developing inside the boiler. It is always set at a pressure which is 3% more than the boiler working pressure.
Read this also: Water Level Controller in Boiler
Main Steam Stop valve– This valve regulates the flow of steam to the distribution lines from boiler. It is slowly opened, so as to avoid any type of water hammering taking place in the distributing lines and damaging them. It is a Screw down non return valve and do not allow steam to come to the boiler back. Adjacent to it an auxiliary steam stop valve is also installed and it is used in case main Steam stop valve is damaged due any reason and making unfit for further use.
Feed Check Valve- Fresh water from hot well tank is supplied to the boiler with the help of these valves. These are also SDNR (Screw down non return valve) type of valve and have a flow that can only go in one direction. It avoids pressurized water inside the boiler to come out and damage the pump, pumping the fresh water.
Water gauges– This piece of equipment is used to measure the level of water inside the boiler. It is very important to keep an eye on the level of water inside the boiler, because if it goes below the normal level, then it can affect boiler working. There are two water level gauges provided in every boiler and one works as a standby type.
Pressure Gauges- To measure the pressure of steam that is being developed inside the boiler, pressure gauges are used. But they are not directly connected to boiler and reason behind this is that, direct steam can damage this piece of instrument. So, a coil which cools down the steam to low levels is used before this pressure gauge.
Salinometer Cocks- These cocks are used to for taking samples of boiler water for taking readings related to the presence of chemical inside the boiler. A cooling coil is also fitted for the high pressure boilers.
Blowdown Valve- This valve is used for purging the boiler. By purging we mean that, in course of time at the bottom of boiler various types of impurities like corrosion deposits, chemical starts accumulating. So, it becomes necessary to remove theses sediments and hence this process is called as the purging.
Scum Valve– Sometimes with feed water, some oil particles come inside the boiler. Now these oil particles starts floating at the top of the water level and this sometimes cause less heat transfer to water. A valve called as Scum is used in order to remove these oily particles and get rid of this problem creating stuff.