Process Glossary.

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Index

A | B | C | D | E | F | G | H | I | J | K | L | M | N | O | P | Q | R | S | T | U | V | W | X,Y,Z

A

 

ABMA

American Boiler Manufactures Association.

ABSORPTION SYSTEM

Refrigeration system that uses lithium bromide as the refrigerant and steam as the means to pressurize the refrigerant.

ACID

The hydrogen form of an ion.

ACID CLEANING

Procedure for removal of waterside deposits in which an acid based material is used as the primary cleaning agent.

ADSORPTION

Physical adhesion of molecules or colloids to the surface of solids without chemical reaction.

AERATION

Process of introducing air into water.

AEROBIC ORGANISM

An organism that requires oxygen for its respiration.

AIRBORNE CONTAMINANT

Solids or gases brought into an open cooling system water in the air flowing through the tower.

ALGAE

Simple plants.  Under conditions favorable for their growth, they mature into colonies and produce mats of similar masses.

ALKALINITY

Bicarbonate, carbonate or hydrate amounts in water.   Usually expressed as "M" alkalinity to a methyl orange titration end point or "P" alkalinity to a phenolphthalein end point.

AMBIENT TEMPERATURE

1.  Outdoor temperature as reported by periodic readings.  2.  Also known as the dry bulb temperature, measured in the regular manner with conventional instruments.                                                       

AMINE

A class of chemical inhibitor used to control rate of corrosion in condensate return piping and related components.  See FILMING AMINE, MORPHOLINE, NEUTRALIZING AMINE AND SOY AMINE.

AMORPHOUS

With a definite crystalline structure.  Atoms or molecules not arranged in a definite pattern.

AMPHOTERIC

A metal oxide that will dissolve in both an acid or alkaline environment, i.e., aluminum, zincs.

ANALYSIS

Separation and measurement of component parts.

ANAEROBE

Type of microorganism which can exist without air or free oxygen.

ANION

Ion which carries a negative charge.

ANODE

Region of lower potential in a corrosion cell.  Area of corrosion where metal is removed.

ANODIC INHIBITOR

Corrosion inhibitor that forms a thin protective film over anode in a corrosion cell.

ANTIFOAM

Class of chemical treatment used in water to limit foaming of system water.

ANTIPRECIPITANT

Chemical that retards the precipitation of insoluble salts, usually by interposing itself in the crystal structure.

ANTISCALANT

Chemical that reacts with impurities to change chemical structure or which alters the action of the impurities.

ANTISEPTIC

Chemical that retards the growth of microorganisms.

APPROACH

Temperature difference, in degrees, between the water leaving a cooling tower and the wet bulb temperature of the air entering the cooling water.

AQUEOUS

Using water as a solvent.

ASME

American Society of Mechanical Engineers.

ATOM

The smallest unit of matter retaining the characteristics of an element.

ATOMIC WEIGHT

Method of comparing weight of an atom with that of an oxygen atom.  Oxygen has an atomic weight of 16; hydrogen has an atomic weight of 1.

ATTRITION

Breakage or wear of ion exchange resins.

AUTOCLAVE

A chamber for sterilizing with steam under pressure.

B

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BACK PRESSURE

Pressure exerted against a flow.

BACKWASH

Upward flow of water through a resin bed to cleanse, expand and classify the resin.

BACTERIA

Large group of one cell microorganisms.  Some strains can produce very adhesive, dense slime type deposits on waterside surfaces of heat exchanger in cooling system.

BASE

The hydroxyl form of a cation or a compound that can neutralize an acid.

BASIN

Lower area of system which system water collects, i.e., bottom area of cooling tower.

BED

Area in an ion exchanger containing resin or exchange medium.

BED DEPTH

Height of resinous material in bed exchanger after exchanger has been properly conditioned for operation.

BED EXPANSION

Effect produced during backwashing of exchanger.

BED VOLUME

The amount of space occupied by the resin bed in cubic feet or gallons.

BHP

See BOILER HORSEPOWER.

BICARBONATE ALKALINITY

Presence in a solution of hydroxyl (OH-) ions resulting from the hydrolysis of carbonates and bicarbonates.

BINDER

Substance which causes particulates to bond together.

BIOCIDE

Group of internal chemical treatments used to control growth of microorganisms (algae, bacteria, fungi) in cooling tower and closed loop systems.

BIOFILM

An aggregate of microorganisms in which cells adhere to each other and/or to a surface.   Biofilms may form on living or non-living surfaces, and represent a prevalent mode of microbial life in natural, industrial and hospital settings.

BIOLOGICAL DEPOSIT

Deposits of microorganisms, or by-products of their life processes, on waterside surfaces.

BLEED

Intentional draining of a portion of system water from cooling tower recirculating system to drain.  Means of controlling concentration of dissolved solids in system water.

BLEED RATE

Rate at which water is bled from cooling tower recirculating system.

BLISTER

Partial or complete failure of boiler tube due to overheating.

BLOWDOWN

Intentional wasting or draining of water from boiler system to waste.  Means to removing sludge from system and also controlling concentration of dissolved solids in system water.

BOD

Also known as Biological Oxygen Demand, a chemical procedure.

BOILER CODE

A set of rules and specifications for designing, constructing, inspecting and operating boilers.

BOILER HORSEPOWER

By definition, the generation of 34.5 lbs. steam/hour from and at 212F°.  By common acceptance, 10 sq. ft. of heating surface is one rated power horsepower.

BRINE

A salt solution, generally sodium chloride.

BTU

Stands for British Thermal Unit.

C

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Ca

Chemical symbol for calcium.

CaCO3

Chemical symbol for calcium carbonate.

CaH

Symbol for calcium hardness.

CALCIUM BICARBONATE

Results of chemical reaction between carbon dioxide, calcium carbonate and water.

CALCIUM CARBONATE

The precipitant resulting from heating of the water that contains calcium bicarbonate.

CAPACITY

Absorption ability possessed by ion exchange material.

CARBON DIOXIDE

Corrosive gas found in most surface and ground water supplies.  Released in the chemical reactions that occur in boiler system water.

CARBONATE ALKALINITY

See "P" ALKALINITY.

CARBONATE CYCLE

A method of internal boiler water treatment in which calcium carbonate is precipitated in the presence of an organic polymer dispersing agent.

CARBONIC ACID

Acid produced from the mixture of carbon dioxide and water.

CARRY OVER

Condition which develops in boiler water resulting in solids and/or chemical treatment being carried out of the system as part of the steam.

CATALYSIS

Addition of a material (catalyst) that does not take a direct part in a chemical reaction, but serves to increase the rate of the reaction.

CATHODE

Region of higher potential in a corrosion cell.

CATHODIC INHIBITOR

Corrosion inhibitor that forms a protective film on the cathode surface of a corrosion cell.

CATHODIC POLARIZATION

Method of inhibiting corrosion by preventing the diffusion, or flow of oxygen, to the cathode site of a corrosion cell.

CATION

Ion which carries a positive electrical charge.

CAVITATION

Metal attack resulting from high flow velocity, variable pressure situations in water containing dissolved or entrained gas.   Evidence of cavitations is often deep circular pits.

CENTRIFUGAL SYSTEM

Compressor type cooling system.

CHANNELING

The flow of water or solution taking the "least line of resistance" through a resin bead.

CHELANT

A sequestrant that prevents an ion from exhibiting its normal properties by complexing (bonding) with it.

CHEMICAL
OXYGEN DEMAND

Amount of oxygen, expressed in parts per million, consumed under specified conditions in the oxidation of organic matter contained in water.

CHLORIDE

Acid radical contained in both surface and ground water supplies.

CHLORIDE TEST

Test performed on water sample to determine total amount of chlorides present.  Results expressed in ppm.   Recommended upper limits to which chlorides can build in system water provides a method for controlling waterside deposits.  Amount of chloride in system water compared to chloride content of makeup or feedwater, provided the means of determining 'cycles of concentration' at which a system is operating.

CHLORINATED PHENOLIC

Non-oxidizing biocide used to control growth of microorganisms in cooling tower recirculating system water.

CHLORINATOR

A device used to meter chlorine into a cooling water at a preselected rate.

CHLORINE

Oxidizing type biocide.  Used to control growth of microorganisms in cooling tower system water.

CHLORINE DEMAND

Amount of chlorine, expressed in parts per million, required to achieve chlorination.

CHLORINE RESIDUAL

Amount of available chlorine present in the system water at any specific time.

CHROMATE

Anodic type corrosion inhibitor that forms a highly passive film of ferric and chromate oxide on the anode of a corrosion cell.

CIRCULATING
HOT WATER SYSTEM

System in which water is heated and circulated through a system of piping, or to a heat exchanger.  In circulating through the system, heat in water is transferred and utilized for space heating, heating of potable water and/or used to clean and sanitize.

CLARIFICATION

External treatment processes which removes suspended solids, turbidity, color and colloidal matter from makeup water.

CLOSED SYSTEM

System in which water is continuously recirculated and loss of water from the system is less than 5% of recirculating rate.

COAGULATION

To bring together small particles into a single large mass which can be filtered or settled out of solution.

COALESCENCE

Process describing the growing together of several different particulates into one larger body.

COD

Abbreviation for CHEMICAL OXYGEN DEMAND.

COGENERATION

The production of both steam and electricity in the same plant.

COLLODIAL

Composed of extremely small size particles which are not removed by normal filtration.

CONC

Abbreviation for concentration.

CONDENSATE

Water condensed from steam.

CONDENSATE POLISHER

Ion exchange resins being used to remove or exchange ions as well as to filter condensate for reuse in steam cycle.

CONDENSATE TANK

Tank or reservoir in a steam boiler system to which condensate flows and collects.

CONDENSER

Heat exchanger in cooling system in which refrigerant gas gives up heat to tower recirculating water.

CONDUCTANCE

A measure of the ability of water to conduct an electric current.

CONDUCTIVITY

The ability of electrical current to flow through water as a measure of its ion content in mhos/cm or micromhos/cm.

CONDUCTIVITY TEST

Test made on any water sample with a conductivity meter to determine amount of total solids present.  Results expressed in 'micromhos', 'mho' or 'conductivity'.   Test results are utilized to control solids in system water within limits to prevent deposition.

CONTAMINATE

Any solid, gas or liquid in system water that is foreign and not normally found under the conditions of operation.

CONTINUOUS BLOWDOWN

Intentional, controlled, continuous flow of boiler system water taken from the top or upper section of boiler to drain.

CONVECTION

Transference to heat by circulation of the heated parts of gas or liquid whereby heated portions are lighter and rise vertically.

COOLING POND

Large body of water (pond or small lake) to which cooling water is pumped and heat contained in water is released to atmosphere by natural evaporation.

COOLING RANGE

Numerical difference between temperature of water entering top of cooling tower and the temperature of water leaving the basin or sump of the tower.

COOLING TOWER

Device for the evaporative cooling of water by contact with air.  Achieved partially by an exchange of latent heat resulting from evaporation of some of the circulating water, and partially by transfer of sensible heat to the air.

COPOLYMER

Polymerization of different monomers on the backbone of a polymer or on its branch chains.

CORROSION

Electrochemical process in which a difference in electrical potential develops between metals or between different sites of the same metal.  The difference in potential results in metal being removed at the anode site.

CORROSION CELL

Two points on different metals, or different sites of the same metal, consisting of an anode and cathode.   Difference in electrical potential between the two points results in metal being removed at the anode site.

CORROSION COUPON

Test metal strip used to measure the rate of corrosion.

CORROSION PRODUCTS

Metal removed as a result of the corrosion process.

CORROSION STRIP

See CORROSION COUPON.

COUNTER FLOW TOWER

Tower where air movement and hot water mix at 180°to each other with air moving vertically through tower fill packing.

CREVICE CORROSION

Corrosion taking place where specific area is isolated from bulk solution, i.e., flange area.

CROSS CONTAMINATION

Intermixing of one resin with another of an opposite charge or of two water streams.

CROSS FLOW TOWER

Tower in which air movement and hot water mix at 90°or cross to each other with air moving horizontally through the fill packing and falling water.

CROSS LINKAGE

The connection between two or more polymer chains to tie them together, as is done by DVB.

Cu

Chemical symbol for copper.

CUPROUS METAL

Metal containing copper.

CUPROUS OXIDE

Passivated oxide state of copper.

CYCLES OF
CONCENTRATION

Ration between the amount of dissolved solids in makeup water and amount of dissolved solids in system water.

CYCLOHEXYLAMINE

Neutralizing type amine.  Used to help control rate of corrosion in condensate return system of steam boiler.

D

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DEAERATOR

External treatment equipment in which boiler feedwater is heated to 212F°+ for the purpose of releasing dissolved oxygen from the water.

DEALKALIZATION

External treatment process by which natural alkalinity or raw makeup water is lowered.

DEFOAMER

See ANTIFOAM.

DEIONIZATION

General term which embraces the removal of all charge ionizable salts (both organic and inorganic) from solution.

DEIONIZE

To remove ions from solution.

DEIONIZER

External treatment process in which raw makeup water, under pressure, passes through a membrane and in the process dissolved solids are removed.

DELINGNIFICATION

Loosening of surface fibers in cooling tower wood members causing a weakening of the timber.

DEMINERALIZE

Removal from solution or inorganic salts by means of adsorption by ion exchange.

DEPOLARIZATION

Any change in the potential of either the anode or cathode or both, which increases the driving force of the corrosion reaction.

DEPOSITION

General term describing accumulation of matter on waterside surface of heating or cooling equipment.   Can be hard scale, sludge, iron oxide, foulants, biological deposits.

DESIGN TONNAGE

Parameters for which a cooling tower is built.  Expressed as cooling a given GPM flow of water entering the tower at a specified temperature-cooling through a given range-leaving the tower at the required temperature.

DEVELOPED TONNAGE

Actual amount of cooling being performed by system.   If system was designed for a 10°cooling range, and water falling through tower is cooled by 5°F, system would have developed tonnage of 50%.

DEW POINT

Temperature at which a given mixture of air and water will have a relative humidity of 100% saturation.

DEZINCIFICATION

Leaching of zinc from brass.

DI  WATER

Useable discharge from dionizer.

DIFFUSION

Spontaneous process of equalization of physical states, i.e., one gas liberated in another.

DISCICCANT

Moisture absorbing material, i.e., quick lime, silica gel, activated alumina.  Used to control condensation in boiler during dry lay-up.

DISPERSANT

Chemical which causes particulates in water to remain in suspension.

DISSOCIATE

The process of ionization of an electrolyte or a salt upon being dissolved in water, forming ions of cation and anion.

DISSOLVED MATTER

Matter, exclusive of gases, present in water.

DISSOLVED OXYGEN

Oxygen which has been freed from compounds contained in natural water supplies.

DISSOLVED SOLIDS

Minerals in surface and ground water supplies which have been dissolved from contact with earth’s surface.

DISTRIBUTION DECK

Area on top of cooling tower into which water, containing heat, is dumped.

DISTRIBUTION SYSTEM

Mechanical method of uniformly distributing hot water over the fill area inside the tower preparatory to cooling.   Low pressure spray through the piping and nozzles is normally used in counter-flow tower, and gravity drop in cross-flow tower.

DRIFT

Water droplets which are entrained in the airstream as it passes through the tower.  Water entrained is carried out of the tower and lost to the atmosphere.

DRIFT ELIMINATOR

Baffling in cooling tower that causes hot air, with entrained droplets, to change direction a number of times causing the droplets to hit eliminator surfaces and fall back into the tower water.

DRUM VENT

Valve on the top of boiler drum.  Used to vent air from boiler at "start up" or when boiler is cooling down.

DRY BULB

Ambient temperature of air measured in standard manner with conventional instruments.

DRY LAY-UP

Period during which equipment or system is non-operational and all water drained and system is left dry.

DS

Abbreviation for dissolved solids.

E

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ECONOMIZER

Heat exchanger placed in gas passage between boiler and stack.  Designed to recover heat.

EDTA

Abbreviation for ETHYLENEDIAMINE TETRAACETIC ACIDChemical referred to as a "chelant".  Forms heat stable complex with calcium, magnesium, iron and copper.

EDUCTOR

A device that, by flow of water through it creating a vacuum, draws a solution into the water stream passing through it.

EFFLUENT

Flow of water out of a tank or from system.

ELECTRIC BOILER

Unit for production of steam by heating water with electrical resistance elements, or by passing AC current through the water between electrodes.

ELECTRODES

Conductive materials placed in water solution which have a positive or negative charge.

ELECTROLYTE

Material that when dissolved in water form ions which are capable of carrying current.

ELECTRON

A sub atomic particle with a negative electrical charge.

ELECTRONEUTRALITY

Where the positive electrical charge equals the negative charge.

ELUTION

To remove ions from a resin by passing other ions in solution of higher concentration or affinity through the resin bed.

EMULSION

A colloidal dispersion of one liquid in another.

ENTHALPY

Total heat content, which is the sum of the sensible heat of the air and water vapor, plus the latent heat of vaporization of the water.

ENTRAINED

To carry or draw along.  The transport of water in a gas or vapor stream.

EQUATION

An expression of a reaction using chemical symbols.

EQUILIBRIUM

The stage in a reversible reaction when there is no driving force in either direction.

EQUILIBRIUM REACTIONS

Interaction of ionizable compounds in which the products obtained tend to revert to substances from which they were formed until a balance is reached in which both reactions and product are present in definite ratios.

EQUIVALENT

Equal valance.

EROSION

Form of corrosive attack associated with metal removal due to high water velocity.

ETHYLENEDIAMINE TETRAACETIC ACID

See EDTA.

EUTROPHICATION

The process by which a lake ages.

EVAPORATION  LOSS

Portion of tower recirculating water lost to the atmosphere in the process of rejecting heat from tower recirculating water.  Amount lost varies depending on level of heat contained in tower water.

EVAPORATIVE CONDENSER

System in which condenser or heat exchanger is located in the cooling tower.  Water is sprayed from nozzles above condenser, while air is blown across condenser tubes or coil.  Refrigerant, inside condenser tubes, is cooled due to the extraction of heat from the refrigerant gas caused by the evaporation of water on the outside of the condenser tubes.

EVAPORATIVE COOLING

Cooling by evaporation of water, heat for which is supplied by air.

EVAPORATOR

Heat exchanger in which chill water or air gives up heat it contains to refrigerant gas.

EXCHANGE SITE

Reactive groups on an ion exchange resin.

EXHAUSTION

State in which resin in water softener is no longer capable of ion exchange.

EXOTHERM

Giving off heat in reaction or solution of a substance.

EXTERNAL TREATMENT

Any process of procedure which removes or reduces solids or gases from water before it enters the boiler or cooling tower system water.

EXTRAPOLATION

Extending information beyond the point where proven data is available.

F

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FAN

An air foil rotating to move air through cooling tower.  Mounted on top of tower (induced draft) or side of tower (forced draft).

FAN STACK

Tower fan housing.

Fe

Chemical symbol for iron.

FEEDWATER

Water feed to boiler. Can be a mixture of condensate and raw makeup, all condensate, or all raw makeup depending on operating conditions.

FERRIC OXIDE

Metal removed in corrosion of iron bearing metal.

FERROUS METAL

Metal constructed from iron, i.e., cast iron, nickel, iron, galvanized steel, silicon, stainless steel.

FILL

Structural material within cooling tower that facilitates contact between water and air.  See FILL PACKING, SLATS, SPLASH PACKING, TOWER FILL.

FILL PACKING

Fill material such as cross-fluting designed to distribute water in thin film in a cooling tower.

FILMING AMINE

Class of inhibitor used to control corrosion in condensate return portion of steam boiler system.  Forms an adherent non-wettable organic film on metal surface thereby preventing contact between metal surface and corrosive condensate water.

FILMING INHIBITOR

General term applied to any treatment which forms an adherent non-wettable film on metal surface preventing contact between metal and system water.

FILTER

Porous media through which a liquid may be passed to effect removal of suspended matter.

FILTRATE

Liquid which passes through a filter.

FILTRATION

External treatment process in which water passes over a filter bed of granular material to effect removal of suspended matter.

FINES

Resin particles smaller than 50 mesh.

FIRE TUBE BOILER

Term used to describe a boiler in which tubes are surrounded by water and fire, and gases pass through inside of boiler tube.

FLASH TANK

Tank into which blowdown from boiler is introduced.  Part of water flashes into steam; remainder is removed from tank as a liquid.

FLOC

Clump of solids formed in water.

FLOCCULANT

Chemical which attaches itself to foulant particles creating a low density, light, fluffy floc that will have little tendency to adhere to metal surfaces.  Floc usually settles or precipitates in the solution.

FMA

Abbreviation for free mineral acid or, sum of the mineral acids.

FOAMING

Small, stable, noncoalesing bubbles formed on water surface in boiler.  Extreme foaming is leading cause of ‘carryover’.

FOG

Symbol for fats, oil and grease in water analysis.

FORCED DRAFT TOWER

Type of cooling tower in which air intake is at bottom and air is forced up and through tower.

FOULANT

Term loosely used to define any type deposit composed of silt, organics, particulates scrubbed from atmosphere, microbiological deposition, dirt, etc.

FREE AVAILABLE CHLORINE

Refers to any unreacted chlorine present in system water.

FREE BASE

The regenerated form of a weak base anion resin.

FREE CO2

Dissolved carbon dioxide gas in water.

FREEBOARD

The space above the resin bed to accommodate resin expansion in backwash step of regeneration.

FUNGICIDE

Chemical that kills fungi.

FUNGUS

A simple plant, containing no chlorophyll and not differentiated into roots, stems or leaves.

G

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GALVANIC CORROSION

Corrosion that occurs when two dissimilar metals are in contact with solution.

GALVANIC SERIES

Table listing metals according to their ability to resist corrosion.

GENERAL CORROSION

Metal attack that is uniformly distributed over a surface.  See  UNIFORM CORROSION and UNIFORM THINNING.

GPD

Symbol for gallons per day.

GPG

Symbol for grains per gallon.

GPH

Symbol for gallons per hour.

GRAPHITIZATION

Selective loss of iron from cast iron.

GRAVIMETRIC

Measurement by weight.

GREENSANDS

Neutrally occurring materials composed primarily of complex silicates, which possesses ion exchange properties.

GROOVING

Term describing corrosion of condensate piping due to carbonic acid attack.  Characterized by development of a groove or flat area in the bottom portion of condensate piping.

GROUND WATER

Portion of water which percolates into the earth's crust and collects in subterranean pools and underground rivers.  Source of well and spring water.

H

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H

Symbol for hardness.

HANDHOLE

An opening in boiler drum or water leg which permits limited visual inspections of internal waterside surfaces.

HARDNESS

A characteristic of water quality generally accepted to represent the total concentration of calcium and magnesium ions.

HARDNESS TEST

Test performed on water sample to determine the presence or absence of the elements of calcium or magnesium.  Results expressed in ppm.  Calcium and magnesium minerals are the principal cause of scale deposits.

HEAT EXCHANGER

Equipment in which heat is transferred from one medium to another.

HEAT LOAD

Amount of heat dissipated in a cooling tower measured in BTU's.

HEAT PUMP

Closed loop system used to extract low-level heat from one medium, normally air or water, boost its temperature and release it into another medium.

“HIGH HEAD"

Term used loosely to indicate pressure of refrigerant gas in compressor higher that it should be at a specified load condition.

HIGH PRESSURE BOILER

Relative term used to indicate boiler operating pressure.  Generally indicates boiler operating at or above 600 psig.

HOT WELL

Closed or open tank in which condensate water is stored.

Hp

Stands for horsepower.

HYDRAULICS

A movement or action resulting from liquid flow.

HYDROMETER

A device to measure specific gravity of fluids.

HYDROPHILIC

Term which means to attract water.

HYDROPHOBIC

Term which means to repel water.

HYDROXYL

Term used to describe the OH radical.

HYPERBOLIC TOWER

Chimney or natural draft type cooling tower.

HYPOCHLORITE

Basic chemical containing chlorine.

I

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IMPINGEMENT

Metal attack usually due to turbulent flow of water high in dissolved or suspended solids or entrained gases.  Results in horseshoe shaped pits.

INDICATOR

Substance that gives visible change, usually of color, at a desired point in a chemical reaction.

INDUCED DRAFT TOWER

Cooling tower with air mover or fan on top of tower pulling air through the tower fill and out through the loop.

INFLUENT

A liquid flow into a system.

INHIBITOR

Generally used to indicate any chemical that aids in control of corrosion.  Also used to indicate some treatments which inhibit scale formation.

INORGANIC MATTER

Matter composed of other than plant or animal matter.

INTERFACE

Point where two substances are in contact one with another.

INTERLOCK

A device which will prevent one action from happening while another action is proceeding.

INTERNAL TREATMENT

Chemical treatment added to system water to aid in controlling corrosion, prevention of waterside deposits or control of microbiological growth.

ION

An atom or radical in solution carrying an integral electrical charge either positive (cation) or negative (anion).

ION EXCHANGE

The interchange of one ion in solution with another ion on an insoluble material.

IONIZATION

Dissociation of molecules into charged positive or negative particles.

IRON FOULING

Plugging of piping, nozzles, etc. with iron oxide or rust.

IRON OXIDE

Metal removed in corrosion process from iron bearing metals.

IRON RELATED BACTERIA

Uses the abbreviation of IRB and is a bacteria which assimilates iron and excretes its compounds in their life process.

J

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K

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L

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LANGELIER INDEX

An index used to determine the scaling or corrosive tendencies of water.

LATENT HEAT

Heat required to change a liquid into a vapor without change of temperature or pressure.

LAYERED OR
STRATIFIED BED

Resins with sufficient difference in density and hydraulic characteristics to be layered in the same tank in place of two separate tanks.

LEAKAGE OR SLIPPAGE

The amount of an ion or ions coming from a resin bead during the service cycle.

LEGIONELLA
PNEUMOPHILA

Legionella pneumophila is a motile, rod-shaped, gram-negative, aerobic, bacterium. It is considered to be a "facultative parasite," which has been identified as the leading cause of Legionnaires’ Disease.

LIGNIN

Major non-cellulose constituent of wood.

LIME SODA SOFTNER

Water softener employing calcium hydrate and sodium carbonate as the reacting chemicals.

LOAD

Term used to express the amount of steam produced by a boiler or heat being rejected by a cooling tower when compared to amount for which system was designed.  If producing or rejecting one half of its designed or rated capacity, system is said to be operating at 50% of load.

LOUVER

Baffle used for purpose of changing the direction of air flow in a cooling tower.  Also to prevent water droplets from splashing out of cooling tower on descent through the structure.

LOW BOILER PRESSURE

Relative term used to indicate boilers operating below 450 psig.

M

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"M" ALKALINITY

Water in which hydrogen ions (acid) predominate, causing pH to be somewhere in a pH range of 4.2-8.4.

MACROPOROUS

Having large pores.

MAGNETITE

The black magnetic, protective film of Fe3O4 normally present on surfaces of steel.

MAKEUP TUBE

Downcomer, supply tube are common tubes used to indicate tubes where circulation of water is down.

MAKEUP WATER

Treated or untreated water introduced into a system to replace any losses.

MANHOLE

Opening in boiler or tank that permits a man to crawl through for internal inspection.

MECHANICAL
DRAFT TOWER

Cooling tower in which air is constantly being moved over water falling through the tower by fans located on the side of the tower.

MEMBRANE

A barrier, usually thin, that permits passage only of particles up to a certain size or of specific nature.

METABOLIC

Undergoing or pertaining to a change in state.

METABOLIZE

To convert food, such as organic matter, to cellular material and gaseous by products by biological process.

MHO

Abbreviation for micromho.

MICROBIOCIDE

A chemical toxic to microorganisms.

MICROMHO

Basic unit of electrical conductance.

MICROORGANISM

Organisms that cannot be seen with the naked eye.  In water treatment they usually refer to organisms that grow in cooling tower environment, i.e., algae, bacteria, fungi.

MIL

Measurement of thickness or depth.  Term used in water treatment to express degree of metal loss due to corrosion.

MILL SCALE

Matter formed on iron or steel in the process of production.  Consists mainly of magnetic iron oxide.

MIXED BED
DEMINERALIZER

External treatment process consisting of a series or system of strong cation or strong anion, weak base anion, mixed bed decarbonator or vacuum deaerator exchange.

Mn

Chemical symbol for manganese.

MOLECULE

The smallest unit of matter retaining properties of a compound.

MOLYBDATE

Filming type of corrosion inhibitor that forms a passivating film on the anode of a corrosion cell.

MONOMER

A single reactive molecule capable of combining with another like itself or another different monomer to form a polymer.

MONOMOLECULAR

A film that is one molecule thick.

MORPHOLINE

Chemical treatment utilized to neutralize carbonic acid in condensate return portion of steam boiler system.

MPY

Abbreviation of mils per year.  Used to express rate of corrosion.

MUD DRUM

Lower drum of boiler where insoluble sludge collects.

N

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NACE

National Association of Corrosion Engineers.

NaCl

Chemical symbol for salt.

NATURAL DRAFT TOWER

Tower in which the air movement through it is dependant only upon atmospheric conditions.

NEGATIVE CHARGE

Electrical potential which an atom acquires when it gains one or more electrons.

NEUTRAL

In pH terms, 7; neither acid nor alkaline.

NEUTRALIZING AMINE

A class of inhibitors that neutralizes carbonic acid by elevating the pH of condensate water from acid to an alkaline state.

NITRATE

Nitrogen as nitrates.

NITRITE

An anodic inhibitor that induces metal to form its own impervious film at the anode site in a corrosion cell.

NOBLE METAL

Metals that are insoluble to any pH, i.e., titanium, molybdenum, nickel.

NON-FERROUS

Metal which does not contain any iron, i.e., cooper, brass, zinc, aluminum.

NON-OXIDIZING TOXICANT

Class of biocide that function by adsorbing onto the microorganism's cell wall.

NOZZLES

Water spouts in distribution decking of a cooling tower.  Breaks up the returning water into droplets and distributes them uniformly over the top of the fill.

NSF

National Sanitary Foundation

NTA

Abbreviation for Nitrilotriacetic Acid.  Used to prevent scaling in boilers and/or as an acid in selective metal deposit control, i.e., iron and manganese in both boilers and cooling towers.

O

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O2

Chemical symbol for oxygen.

"OFF THE LINE"

Term used to denote a system that is in short or long term layup.

“OH” ALKALINITY

See "P" ALKALINITY.

OHM

A unit of resistance to the passing electric current.

“ON LINE
STREAM CLEANING”

Method of removing waterside deposits while system remains in operation.

ONCE THROUGH SYSTEM

Any system in which water is only used once and then put to the drain.

OPEN
FEEDWATER HEATER

Tank in which feedwater is heated by steam, but where temperature does not go above atmospheric.

ORGANICS

Carbon containing compounds generally from vegetation or non-mineral origin.

ORGANO-TIN

Non-oxidizing "heavy metal" inorganic biocide used for the control of microorganisms in system water.

ORTHOPHOSPHATE

1.   Internal chemical treatment that functions as an anodic inhibitor or antiscalant.  2.  A sludge resulting from the revision of polyphosphate.

OSMOSIS

Process where water on one side of a membrane tries to pass through the membrane to dilute a salt solution on the other side in an attempt to equalize the concentration of salt on both sides.

OXIDATION

The addition of oxygen, the removal of hydrogen, or the loss of electrons.

OXIDE

A compound composed of metal and oxygen.

OXYGEN

An element occurring free as a colorless, tasteless, odorless gas.

OXYGEN SCAVENGER

Chemical used in treatment of boilers to reduce last traces of dissolved oxygen in system water.  Sodium sulfite most widely used type.

P

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"P" ALKALINITY

Water in which hydroxyl ions (alkaline) predominate, causing pH of system water to be above 8.2.  Also referred to as caustic, OH or carbonate alkalinity.

PACKAGED BOILER

A shop assembled steam boiler generator with necessary auxiliary equipment complete and ready to use.

PACKING

Slats, baffling or corrugated fill found inside the casing of a cooling tower.

PARAMETERS

Two figures indicating an upper and lower limit.

PARTICULATE MATTER

Any matter, exclusive of gases, existing in a non-liquid state of water.

PASSIVATION

The transformation of a metallic surface to a state in which it does not readily oxidize.  Usually accomplished by forming a protective film on metal surface.

pH

A measure of the concentration of hydrogen ions in water.  pH is a number between 0 and 14, denoting various degree of acidity or alkalinity.  Neutral water has a pH of 7.  Values below 7 and approaching 0 are increasingly acid while values from 7 to 14 are increasing alkaline.

PHOSPHATE

Chemical used in treatment of boilers that aids in prevention of scale type deposits.

PHOSPHONATE

1.  Cathodic corrosion inhibitor for ferrous metal.  2. Deposit control agent.

PITTING

Term that describes localized attack on metal surface.  Results in crater-like indentations in metal.

PITTING FACTOR

Ratio of a pit to the average depth of metal penetration.

PLANKTONIC

Floating or swimming in water.

PO4

Chemical symbol of phosphate.

POLORIZATION

Extent of potential change in volts, caused by net flow of current to or from an electrode.  When there is no difference in potential between the anode and cathode, corrosion ceases and the metal is said to be in a "passive" state.

POLYACRYLATE

Synthetic polymer formed from monomers.  Used as a boiler and cooling water dispersing agent.

POLYELECTROLYTE

A high molecular weight water soluble polymer with high charge density or multi-charged ions.

POLYMER

Synthetic chemicals with long chain molecules of repeating units.

POLYMERIZATION

The act of reacting monomers to form a long chain polymer.

POROSITY

The degree of openness or a sponge-like quality.

POSITIVE CHARGE

The electrical potential acquired by an atom which has lost one or more electrons.

POTABLE WATER

Water which meets drinking water quality standards.

PPB

Stands for parts per billion.

PPM

Stands for parts per million.

PRECIPITATE

Matter that has separated out of solution as a result of chemical reaction or physical change.

PRECIPITATING PROGRAM

A treatment program that results in precipitation from solution to scale forming contaminates in the form of non-adhering sludge.

PRESSURE DROP

Static pressure or amount of resistance in air or liquid caused by system piping or obstructions in system fabrication.

PRETREATMENT

Any process or procedure which removes or reduces solids or gases from water before it enters the system.

PRIMING

Spasmodic actions resulting in spouting or surging of boiler water into steam header or outlet.

PROCESS STEAM

Steam used to heat or operate some manufacturing process.

PROCESS WATER

Water used in a product or in manufacture of a product.

PUMPING HEAD

Energy required to raise water and overcome friction losses inherent in fabrication of the system.

Q

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QUAT

Stands for Quaternary ammonium cations that are positively charged polyatomic ions of the structure NR4+, R being an alkyl group. Unlike the ammonium ion (NH4+) and the primary, secondary, or tertiary ammonium cations, the quaternary ammonium cations are permanently charged, independent of the pH of their solution.

R

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RADIANT HEAT

Heat supplied by radiation without necessity of some medium transmission, i.e., heat from the sun.

RANGE

Numerical difference between the water temperature entering the cooling tower at the top, and the cold water leaving the basin or sump at the bottom of the tower.

RATED TONNAGE

Thermal parameters for which a cooling tower was designed.

RAW WATER

Natural water as it comes from the environment or municipal water treatment plant.

REAGENT

Any substance which, from its capacity for certain reactions, is used in detecting, examining or measuring other substances.

RECEIVER

Tank or reservoir to which steam condensate flows and makeup water is introduced into boiler system.

REGENERANT

A chemical used to restore the ion exchange resin back to its desired form.

REGENERATION

Process by which an ion exchanger is restored to its operative form.  Water softener regeneration involves four steps; backwash, brining, slow rinse and fast rinse.

REHEAT

Returning partially expanded steam to a boiler so that additional heat is added before the steam passes through the final stages of a turbine.

RELATIVE HUMIDITY

Ration of water vapor pressure in the air to the saturated vapor pressure at the same temperature usually expressed as a percentage.  Also the number of pounds of water carried by one pound of dry air.

RESISTANCE

The property of opposing the flow of electric current.

RETURN

The warm water returned to top of cooling tower.

REVERSE OSMOSIS

The reverse flow of water through a membrane by applying pressure to overcome osmotic pressure.

RINSE

Step in regeneration of an ion exchanger.

RISER

The vertical section of piping that carries hot water to the top of the cooling tower.

RO

Abbreviation for reverse osmosis.

RYZNAR STABILITY INDEX

An index to determine the scaling and corrosion tendencies of water.

S

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SAC

Abbreviation for strongly acidic cation resin.

SALINITY

The presence of soluble minerals in water.

SAPONIFICATION

The hydrolysis of a fat or alkali.

SATURATED

The maximum amount of a substance that can be put into the solution.

SATURATED STEAM

Steam that is saturated with heat at a particular temperature and pressure.

SBA

Abbreviation for strongly basic anion resin.

SCALE

A hard adherent, crystalline layer or layers.  By analysis usually contains well over 50% of calcium and magnesium.

SCALE INHIBITOR

Term broadly used when referring to any treatment that reacts with calcium or magnesium ions preventing them from depositing as scale.

SEDIMENTATION

Gravitational settling of solid particles in a liquid.

SENSIBLE HEAT

Heat you can feel.  Heat required to change the temperature of air or water.

SEQUENTIAL

One action occurring followed by others in a given order.

SEQUESTRANT

Term used that describes any chemical that forms a stable, water soluble complex.

SESSILE

Permanently fixed or unable to move.

SETTLEABLE MATTER

Matter that will settle out of solution by gravity under low flow conditions.

SHOCK FEED

Introduction of a large quantity of chemical treatment into system water within a very short period of time.  Term usually used to describe feed of biocide into tower cooling system.

SHOT FEED

Chemical feed system in which water flow, from high to low pressure side, forces chemicals from a feed tank into the system.

SIGHT GLASS

Glass tube mounted on outside of boiler indicating the water level within the boiler.

SILICA

Element found in water.

SIO2

Chemical symbol for silica.

SKIMMER

See CONTINUOUS BLOWDOWN.

SLATS

Thin strips of wood or plastic suspended from frames inside cooling tower.

SLIME

A soft, sticky mucus-like substance originating from bacterial growth.

SLIMICIDE

Another term for biocide.

SLUDGE

Matter in solution or matter that collects at the bottom of boiler drum.

SLUDGE CONDITIONER

Natural or synthetic treatment that aids in preventing coagulation of system water particulates into a large floc or mass.

SLUG FEED

See SHOT FEED.

SO3

Chemical symbol for sulfite.

SODIUM CHROMATE

Filming type corrosion inhibitor

SODIUM SILICATE

Anodic corrosion inhibitor that hydrolyzes in water to form negatively charged colloidal particles which migrate to anodic site of corrosion cell.

SODIUM SULFATE

By product of reaction between sodium sulfite and dissolved oxygen.

SODIUM SULFITE

Treatment used to aid in reducing dissolved oxygen in steam boiler system.

SOFT WATER

Water that contains little or no calcium or magnesium.

SOFTENER

External treatment process in which calcium and magnesium (hardness) are removed and replaced with sodium by cation exchange.

SOLUBILIZING PROGRAM

A deposit control program in which deposit forming cations are complexed (tied up), held in solution and dispersed in colloidal form in system water.

SOLUBLE OIL

Anodic inhibitor that forms negatively charged particles which migrate to anode of corrosion cell and precipitate, with metal ions, onto the anode site.

SOY AMINE

 An acceptable food grade FILMING AMINE.

SPECIFIC GRAVITY

The ratio of the weight of a given volume of a substance to the weight of an equal volume of water at a fixed temperature.

SPECIFIC RESISTANCE

The resistance between opposite faces of a one centimeter cube of a given substance and expressed in ohm-cm3.

SPLASH PACKING

Type of cooling tower fill consisting of slats so arranged that water falling through the tower is broken up into small droplets thus achieving better contact with air.

SPORE

A cell in a resistant envelope, capable of developing into a normal organism.

SPRAY FILLED TOWER

Cooling tower in which breakup of water is dependent solely on spray nozzles.

SPRAY POND

System in which hot water in a cooling tower is pumped to a large pond or small lake, sprayed into the atmosphere through nozzles, and cooled by natural evaporation.

SRB

See SULFATE REDUCING BACTERIA.

SS

Chemical symbol for suspended solids.

STABILITY INDEX

See RYZNAR STABILITY INDEX.

STABLE WATER

Water which is neither scale forming nor corrosive.

STAGE HEATER

Device for heating feedwater.

STAND BY

Period during which system or equipment serves as a "back up".

STATIC

An ion exchange reaction occurring with a volume of liquid in contact with a volume of resin.

STEAM BOILER

Any device for the production of steam under pressure.

STEAM DRUM

The upper boiler drum where steam is produced and withdrawn.

STEAM GENERATOR

See STEAM BOILER.

STEAM HEADER

Large pipe, usually located on top of steam drum, through which steam exits a boiler.

STEAM PURITY

Measurement which expresses the amount of contamination, either organic or inorganic, contained in steam.

STEAM QUALITY

The ratio of the weight of vapor to total weight of the steam water mixture.

STEAM TRAP

A device for bleeding condensate out of a steam line without allowing steam to escape.

STOICHIOMETRIC

Chemical reaction that results in a change in chemical solution.

STRAINER

A screen to remove matter that would otherwise cause plugging or deposits.

SUBSTOICHIOMETRIC

1 to 1 ratio reaction.  See STOICHIOMETRIC.

SULFATE
REDUCING BACTERIA

Bacteria which assimilate oxygen from sulfate compounds, reducing to sulfide.

SULFITE TEST

Daily test performed on boiler system water to determine the amount of sodium sulfite present.  Results expressed in ppm.  When sulfite residual is within prescribed range-usually 20ppm-60ppm, it is assumed no dissolved oxygen is present and therefore, 'pitting' type corrosion is under control.

SUMP

See BASIN.

SUPER CRITICAL BOILER

Boiler operating at a pressure higher than the critical pressure, 3203.6 psig.

SUPER HEAT

The number of degrees Fahrenheit of steam above the temperature of saturated steam at some specified pressure.

SUPER HEATER

Tubes within a boiler through which saturated steam passes after leaving a boiler and where steam absorbs additional heat.

SUPER SATURATED

To contain more in solution than normal for a given temperature.

SUPPLY

Cooled water flowing from the basin or sump of a cooling tower.

SUPPORT MEDIA

A graded particle size, high density material such as gravel, anthrafil, quartz, etc. used to support the resin bed.

SURFACE BLOWDOWN

See CONTINUOUS BLOWDOWN.

SURFACE TENSION

The resultant attractive forces on molecules at the surface of a liquid, exerted by molecules within the liquid, that tends to make the surface contact to the smallest possible area.

SURFACE WATER

Water which has a short contact with the earth's surface collecting in streams, rivers, lakes and reservoirs.

SURFACTANT

Chemical that alters the surface and interfacial tension.

SURGING

See PRIMING.

SUSPENDED MATTER

1.  Finely dispersed particles of impurities of water, including industrial waste, silt, and organic substances.  2.  Mineral salts (hardness) that has precipitated out of solution due to the heat or other influences.

SYMBOSIS

Relationship between a microorganism and a host that is beneficial to both.

SYNERGISM

1.  A cooperative effort between two or more species of bacteria resulting in something the individual species could not accomplish alone.   2.  Blending together of two or more chemicals so that the total effect is greater than the sum of the single effect taken separately.

T

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TDS

Chemical symbol for total dissolved solids.  See TOTAL DISSOLVED SOLIDS.

TH

Chemical symbol for total hardness.

THRESHOLD TREATMENT

Control of scale type deposits by feeding of a sub-stoichiometric dosage of treatment to system water.

TITRATE

Determining the amount of a substance in solution by adding a measured amount of another substance to produce a desired reaction or end point.

TOC

Total Organics Carbon is the amount of carbon bound in an organic compound and is often used as a non-specific indicator of water quality or cleanliness of pharmaceutical manufacturing equipment.

TON

Term used to express capacity or size of a cooling system.  Equal to 15,000 Btu per hour.

TONNAGE

Term used to indicate rated capacity of cooling system.

TOTAL CHLORINE RESIDUAL

Total amount of chlorine present, without regard to type.

TOTAL DISSOLVED SOLIDS

Term indicating the total amount of dissolved solids present in a water sample.  Usually expressed as TDS in parts per million.

TOWER

See COOLING TOWER.

TOWER CIRCULATION PUMP

Pump that recirculates water to and from the cooling tower.

TOWER FILL

Tower which contains baffling inside used to increase break-up of water falling through tower into small droplets or sheets, and also to provide additional wetted surface.

TRICHLOROPHENATES

Non-oxidizing microbiocide.

TS

Chemical symbol for total solids.

TSS

Chemical symbol for total suspended solids.

TUBE

A hollow metal cylinder to convey liquids or gases.

TUBE SHEET

Area in boiler or heat exchanger to which tubes are affixed or fabricated.

TUBERCULATION

A hard, dense, scab-like deposit of metal oxide on metal surface.

TURBIDITY

A suspension of very fine colloidal size particulates that obscures light rays, but requires many days of sedimentation due to the small particulate size.

TURBINE

Rotary device, powered by boiler steam, whose function is to drive some other rotating piece of equipment.

TURNOVER

The mixing of lower and upper layers in a lake in spring and fall.  Caused by temperature and density equalization.

U

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UMHOS

Abbreviation for micromho.

UNDER
DEPOSIT CORROSION

Corrosion that takes place under any type of deposit due to the differential aeration or temperature.

UNIFORM CORROSION

See GENERAL CORROSION.

UNIFORM THINNING

Type corrosion in which metal is uniformly removed and thinned.  Generally associated with metal exposed to low pH or acid solution.

USDA

United States Department of Agriculture.

V

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VALANCE

The number of positive or negative charges on an ion.

VOLATILE AMINE

Treatment used to aid in control of corrosion in condensate system of boiler.

W

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WAC

Stands for weak acid cation resin.

WALL TUBE

Tube containing boiler water that shields refractory furnace walls by absorbing heat.

WATER FORMED DEPOSIT

Any accumulation of insoluble material derived from water or formed by the reaction of water upon surfaces in contact with water, i.e., scale, sludge, corrosion by-products or biological deposits.

WATER TUBE BOILER

Boiler in which water is on the inside of the boiler tubes and flame and gases are on the outside.

WET BULB TEMPERATURE

Temperature of saturated air.

WET LAYUP

Period during which system or equipment is non-operational and left full of water.

X, Y, Z

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ZEOLITE

A mineral composed of hydrated silicates of aluminum and sodium or calcium.

ZEOLITE SOFTENER

A term loosely used to designate a sodium regenerated ion exchange softener.

ZINC

A non-ferrous metal.

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