ECCENTRIC SHEAVE -- The sheave of an
eccentric, often formed intergral with the shaft. (Reciprocating steam
engine)
ECCENTRIC STRAP -- A narrow split bearing, fitting on to an
eccentric sheave and bolted to the end of a valve rod, ect.; corresponds to the
"big end" of the connecting-rod.
ECONOMIZER -- A heat exchanger that transfers heat from the
gases of combustion to the Boiler Feedwater.
EDUCTER -- A device to draw air out.
EJECTOR -- A device for exhausting a fluid by entraining it by
a high-velocity steam or air jet.
ELECTRIC BOILER -- A boiler in which electric energy is used
as the source of heat.
Low voltage boilers are mainly heated by means of electric elements.
High voltage boilers are always heated by means of electrodes directly in the
water.
Element boilers often range from 20 to 3000 kW for a standard voltage of 400
Volt (3-phase). Electrode boilers range from 100kW to 1500kW for 400Volt and 1
to 60MW for a standard voltage of 10kV (3-phase).
EMERGENCY LOW WATER LEVEL TRIP -- A device that
shuts down the fuel supply when the water level in the boiler drops below its
operating level. This prevents burning out of tubes, boiler damage or possible
boiler explosion.
ENDOTHERMIC -- A process that absorbs heat.
ENTHALPY -- Thermodynamic property of a working substance
defined as H = U+PV, where
U = internal energy,
P = pressure and
V = volume of system. Useful in studying flow
process, replacing total heat.
ENTRAINMENT -- Transport of small liquid particles in vapor,
e.g., when drops of water are carried over in steam.
EVAPORATIVE CAPACITY -- The mass of steam at a stated
temperature and pressure produced in on hour from a unit area of heating
surface from feedwater at a stated temerarure, when steaming at the most
economical rate. Measured in kg/m² h (or lb/ft² h).
Also called evaporation rate.
EXCESS AIR -- Air supplied for combustion in excess
of the air theoretically required for complete combustion of the fuel.
EXHAUST GAS DAMPER -- Used to control the pressure in an
exhaust gas boiler. It bypasses the heat exhaust gases to reduce the steam
production in the exhaust gas boiler.
Nowadays a control valve normally dumps the excess steam to a dump
condenser.
EXOTHERMAL -- A process that gives out heat.
EXPANSION JOINT-- A junction that allows for expansion and
contraction.
EXPRESS BOILER -- In these boilers the tubes are made of
smaller diameter than those used in other boilers. The Yarrow express boilers
are of similar construction as the large tube Yarrow boilers with the exception
that the tubes are smaller in diameter and much more closely arranged.
EXTERNAL MIX STEAM ATOMIZER -- Is designed to make
full use of pressure jet atomization at high outputs and full use of blast
atomization at low outputs.
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