BABCOCK & WILCOX BOILER -- A water tube boiler
consisting of a horizontal drum from which is suspended a pair of headers
carrying between them an inclined bank of straight tubes.
BACKWASH -- A stage in the regeneration cycle of a softener or
other ion-exchanger equipment during which water-flow through the unit is
directed upwards through the resin bed. This is done to clean and reclassify
the bed following exhaustion.
BAFFLE -- A plate used to prevent the movement of gases or
liquids in the direction that it would normally follow, and to direct it into
the desired path.
BALANCED DRAUGHT -- A system of air-supply to a boiler
furnace, in which one fan forces air through the grate, while a second,
situated in the uptake, exhausts the flue gas. The pressure in the furnace is
thus kept atmospheric, i.e., balanced.
BAROMETRIC DRAFT CONTROL -- A damper, mounted on the vent
stack of a furnace or boiler that maintains the draft at a constant level.
BARRING GEAR -- Arrangement for moving the
engine by manpower, used to turn the engine slowly for adjustment or
inspection.
BARRING MOTOR -- Motor connected to the barring gear in large
engines.
BENSON BOILER -- A high-pressure boiler of the once-through
type in which water is pumped through the successive elements of the heating
surface, fired by oil or gas.
BEVEL GEAR -- A system of toothed wheels connecting shafts
whose axes are at an angel to one other but in the same plane.
BIMETALLIC ELEMENT -- A device consisting of two different
metals fastened together which bends in a certain direction depending on the
temperature. Commonly used in thermostats.
BILGES -- The lowest part of the interior of a vessel's hull
where any internal water collects.
BLAST PIPE -- The exhaust steam pipe in the smoke box of an
locomotive-boiler, which terminals in a nozzle to provide draught by entraining
the flue gases in the steam-jet and exhausting them through the chimney.
BLOWDOWN VALVE -- Blow-down valves are fitted on the mud drum
and should the testing of boiler water indicate the need for blowing down, the
blow-down valves should be opened wide quickly for successive short periods in
order to remove any deposit and to prevent the choking of the valve or cutting
the valve plug or zeat. Boilers above 20 bar, at the superheater outlet are
fitted with double blow-down valves and the valve attached to the boiler must
be treated as a shut-off valve and is to be full open during blowing.
IMPORTANT. When boilers have water cooled furnace walls, the drain valves on
the water wall headers must never be opened when the boilers are steaming.
BLOWER -- A fan used to force air under pressure.
BLOW-OFF VALVE -- Also called bottom blowdown valve.
BLUE FLAME BURNER -- Some of the hot gases from the
flame are recirculated back to the inlet where they mix with and heat the
combustion air.
BOILER CAPACITY -- The weight of steam, usually expressed in
kg or lb/hr, which a boiler can evaporate when steaming at full load output.
BOILER COMPOSITIONS -- Chemicals introduced into boiler
feed-water to inhibit scale-formation and corrosion, or to prevent priming or
foaming. Examples are sodium compounds (such as soda ash), organic matter, and
barium compounds.
BOILER CRADLES -- The wrought-iron saddles or standards that
support cylindrical boilers of the Scotch marine type. Also called Keelson.
BOILER CROWN -- The upper rounded plates of a boiler of the
shell type.
BOILER FEED WATER PUMP -- Two pumps are normally installed,
one for operation and the other for stand-by purpose. The stand-by pump has to
start upon low pressure in the feed water line to the boiler.
BOILER HEATING SURFACE -- The area of the heat transmitting
surfaces in contact with the water or the steam in the boiler on one side and
the fire or hot gases on the other.
BOILER HORSE POWER -- One boiler horse power is equal to an
evaporation rate of 34.5 pounds (15.649kg) of water per hour from and at
212°F (100°C).
That is 33471.403...BTU/h (9.8095...kW).
Boilers in ships were not customarily rated in boiler horsepower.
BOILER SCALE -- A hard coating, chiefly calcium
sulphate, deposed on the surfaces of plates and tubes in contact with water in
a steam-boiler. If excessive, it leads to overheating of the metal and ultimate
failure.
BOILER SHELL -- The outer cylindrical portion of a pressure
vessel.
BOILING OUT -- The boiling of highly alkaline water in boiler
pressure parts for the removal of oils, greases, etc.
BOILERS -- Boilers are usually classified as
water-tube boilers or
fire-tube boilers. In the fire-tube boiler the combustion
occurs in heavy duty tubes and the flue gases carries off through smoke tubes.
In the water-tubes boiler the water flows in tubes surrounded by the combustion
gases.
BOTTOM BLOW VALVE -- A valve located near the bottom of the
boiler for the purpose of blowing off the mud and sediment.
BRACING -- The stay rods, stay bolts and stay tubes used in
supporting the flat surfaces in a boiler.
BRIDGEWALL -- A wall in a furnace over which the products of
combustion pass.
BTU --
British
Thermal Unit, the amount of energy required to raise one pound of water by
one degree Fahrenheit.
BUCK PLATES -- Steel plates used to tie together with tie-rods
the brickwork of a furnace.
BUCKSTAY -- A structural member placed against a furnace or
boiler wall to restrain the motion of the wall.
BULKHEAD -- A partition within a ship's hull or
superstructure. It may be transverse or longitudinal, watertight, oiltight,
gastight, or partially open. It may form part of the ship's subdivision for
seaworthiness or otherwise.
BURNER WINDBOX-- A plenum chamber around a burner that
maintains an air pressure sufficient for proper distribution and discharge of
combustion air.
BUSBAR -- A heavy, rigid conductor used as a common connection
for two or more electrical circuits.
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