Boiler glossary A

ABRADANT -- A substance, usually in powdered form, used for grinding.
ABSOLUTE PRESSURE-- Pressure above zero pressure; the sum of the gauge and atmospheric pressures.
ACCELERATED FATIGUE TEST -- The application, mechanically, of simulated operating loads to a machine or component to find the limit of safe fatigue life before it is reached in service.
ACCEPTABILITY -- When single results are obtained in two laboratories and their difference is less than or equal to the reproducibility, the two results shall be considered as acceptable and their average, rather than either one separately, shall be considered as the estimated value of the tested property. If the two results differ by more than the reproducibility, both shall be considered suspect. See Repeatability and Reproducibility
ACID CLEANING -- The process of cleaning the interior surfaces of steam boiler units by filling the unit with a dilute acid accompanied by an inhibitor to prevent corrosion and by subsequently draining, washing, and neutralizing the acid by a further wash of alkaline water.
ADIABATIC -- A process in which there is no heat transfer, thus its temperature-entropy graph is a vertical straight line, and thus entropy is constant during the process.
AIR ATOMIZING OIL BURNER -- A burner in which compressed air is introduced to the fuel oil gun to break of the oil into a fine spray.
AIR DEFICIENCY -- Insufficient air. More air is required for complete combustion of the fuel.
AIR-FUEL RATIO -- The ratio of air weight to fuel wight consumed in a furnace.
AIR PUMP -- A reciprocating or centrifugal pump used to remove air, and some tomes the condensate, from the condenser of a steam plant.
AIR VENT -- A valved opening in the top of the highest drum of a boiler or pressure vessel for venting air.
ALKALINITY -- Represents the amount of carbonates, bicarbonates, hydroxides and silicates or phosphates in the water. See pH VALUE
ALLAN VALVE -- A steam-engine slide-valve, in which a supplementary passage increases the steam supply to the port during admission to reduce the wire-drawing.
ALLOWABLE WORKING PRESSURE -- The maximum pressure for which the boiler was designed and constructed; the maximum gauge pressure on a complete boiler and the basis for the setting on the pressure relieving device protecting the boiler.
ALUMINA -- Except in a few sections, this impurity in the boiler water is not troublesome.
AMINE -- Chemical used to control corrosion in condensate system.
ANION -- A negatively charged ion.
ANODE -- The positive electrode of an electrochemical cell where electrons are donated and oxidation occurs.
ANSI -- American National Standards Institute. The coordinating organization for federal national standards system.
API -- American Petroleum Institute. The API degree is related to the specific gravity scale by

ANTHRACITE BUCKWHEAT COAL -- A hard natural coal, containing little volatile matter, commonly used in mechanical types of firing equipment.
ARRESTER -- A device to impede the flow of large dust particles or sparks from a stack, usually screening at the top.
ASH PIT -- A pit or hopper located below a furnace where refuse is accumulated and from which refuse is removed at intervals.
ASME -- American Society of Mechanical Engineers.
ASTM -- American Society for Testing Materials. Grade and quality specifications for petroleum products are determined by ASTM test methods.
AUTOMATIC VENT DAMPER -- A thermally or electrically actuated damper, located on a furnace or boiler vent that closes when the heating equipment is between firing cycles.
ATOMIZER -- A device by means of which a liquid is reduced to a very fine spray.
ATOMIZATION CHARACTERISTICS -- The ability of an oil to be broken up into a fine spray by some mechanical means.
ATOMIZING STEAM -- Low-pressure steam that is introduced to the fuel oil gun to break of the oil into a fine spray.
AUXILIARY ENGINE -- An engine that provides electric power.