Boiler glossary G
|GALLOWAY BOILER -- A cylindrical boiler of the Lancashire
type, in which the two furnace tubes unite, at a short distance from the
grates, into a single arched oval flue, crossed by water tubes.
GALLOWAY TUBES --The inclined water tubes which cross the flue of a Galloway boiler to assist circulation and increase the heating surface.
GALVANIC CORROSION -- Accelerated corrosion of a metal because of an electrical contact with a more noble metal or nonmetallic conductor in a corrosive electrolyte.
GASOHOL -- A blend of finished motor gasoline containing alcohol (generally ethanol but sometimes methanol) at a concentration between 5.7 percent and 10 percent by volume.
GAS OIL -- European and Asian designation for No. 2 diesel fuel.
GAS TIP -- The part of a burner that discharges the gas fuel via one or more openings into the furnace.
GATE VALVE -- A stop valve using the wedge-and-double-seat principle. It may be used to control fluids containing some solids, for when wide open, it operates on a straight-through flow.
GAUGE GLASS -- The glass tube, or pair of flat glass plates, fitted to a water-gauge to provide a visual indication of the water-level in a boiler or a tank.
GAUGE COCKS -- Small test cocks fitted to the side of a vessel to ascertain the liquid level therein, as on many steam boilers.
GAUGE PRESSURE -- Of a fluid, the pressure as shown by a pressure gauge, i.e., the amount by which the pressure exceeds the atmospheric pressure, the sum of the two giving absolute pressure.
GEAR PUMP -- A small pump consisting of a pair of gear-wheels in mesh, enclosed in a casing, the fluid being carried round from the suction to delivery side in the tooth spaces; used for lubrication systems, etc.
GENERATING STATION -- A power plant.
GIRDER -- A beam, usually steel, to bridge an open space. Girders may be rolled sections, build up from plates, or of lattice construction
GLOBE VALVE -- A stop valve using the round-disk-and-seat principle. Used where the fluid controlled is comparatively clean.
GRADE -- Oil classification according to quality, generally based on ASTM specifications.
GRATE -- That part of a furnace which supports the fuel. It consists of fire bars or bricks so spaced as to admit the necessary air.
GRAVITY HEATING SYSTEM -- A system in which the heating medium circulates naturally because of the temperature difference between the supply and return medium.
GUNBOAT BOILER -- A boiler with limited height that made it possible to have the boiler installed entirely below the sea water line and hence protected from direct hits.