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Boiler glossary B |
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| 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. BLOWDOWN -- The periodic removal of water from a boiler to remove concentrations of sludges accumulating in the boiler. BLOWER -- A fan used to force air under pressure. BLOW-OFF VALVE -- A specially designed, manually operated, valve that connects to the boiler for the purpose of reducing the concentration of solids in the boiler or for draining purposes. Also called bottom blowdown. 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. 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. 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. 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. |
© 2007 Lars Josefsson Boilers