BOILER MOUNTINGS & ACCESSORIES:
• Boiler mountings are primarily intended for the safety of the boiler and for complete control of steam generation process.
Boiler Accessories :
• Boiler accessories are installed to increase the efficiency of the boiler plants to help in proper working of boiler unit.
• Dead weight safety valve.
• Spring loaded safety valve
• Fusible plug
• Pressure gauge
Dead Weight Safety Valve:
Dead Weight Safety Valve:
• Weights are placed sufficiently in the weight carrier.
• The total load on the valve includes the weight of the carrier, the weight of the cover, the weight of the discs and the weight of the valve itself.
• When the steam pressure exceeds the normal limit, the valve along with the weight carrier is lifted off its seat.
• Thus the steam escapes through the discharge pipe.
Spring Loaded Safety Valve:
• The steam pressure a cts below the valves.
• When the steam pres sure is normal the valves are held in their seats tightly by the spring force.
• When the steam presssure in the boiler exceeds the working pressu re, both valves are lifted off their seats.
• Thus the steam from the boiler escapes the boiler and steam pressure is reduced.
• The blow off pressure is adjusted by loosening or screwing the nut.
• Under normal workin g conditions, the fusible plug is completely covered with water.
• Hence the temperature of the plug is not increased appreciably du ring combustion process.
• When the water level falls below the safe limit the fusible plug is unc overed from water and exposed to steam.
• The furnace heat over heats the plug and it melts the fusible me tal and
copper plug falls down.
• Due to this water st eam mixture rushes into the furnace and the fire is extinguished.
Bourdan Tube Pressure Gauge
• The steam pressure is applied to the
• The elliptical cross section of the tube to straighten out slightly.
• The closed end of the Bourdon tube moves.
• This movement actuates the toothed sector and pinion rotates.
• The pointer is mounted on the pinion. Hence the pointer moves on the graduated dial in clockwise, to indicate the steam pressure.
Water Level Indicator
• To know the water level in the boiler the handles of the steam cock and water cock are kept in vertical positions.
• Water rushes through the bottom casting and steam rushes through the upper casting to the gauge glass tube.
• The level of water corresponds to the water level in the boiler.
DIFFERENCES BETWEEN BOILER MOUNTINGS AND ACCESSORIES:
Mountings are fitted for the safety of the boiler.
They form integral parts of the boiler
They are usually mounted on the boiler shell
A boiler should not be operated without mountings
Accessories are fitted to increase the efficiency
They are not integral part of the boiler
They are usually installed outside the boiler shell
A boiler can be operated without accessories