All Terms 4 Flashcards
1
Q
HYDRAULIC COUPLING
A
A fluid connection between a prime mover and the machine it drives. It uses the action of liquid moving against blades to drive the machine.
2
Q
HYDRAULIC HEAD
A
The force exerted by a column of liquid expressed by the height of the liquid above the point at which the pressure is measured. Although head refers to a distance
3
Q
HYDROCARBONS
A
Organic compounds containing only hydrogen and carbon atoms in various combinations.
4
Q
HYDROGEN CYCLE
A
A complete course of cation
5
Q
HYDROGEN DAMAGE
A
A type of corrosion occurring beneath a relative dense deposit. This type of damage can only occur if hydrogen was present in the metal. Failure takes place at
6
Q
HYDROGEN INDUCED CRACKING
A
Caused by the introduction of hydrogen during the welding process.
7
Q
HYDROGEN ION
A
A portion of the molecule of water containing one atom of hydrogen which has a positive electric charge.
8
Q
HYDROGEN
A
ION CONCENTRATION
9
Q
HYDROLOGIC CYCLE
A
The cycle of water from evaporation through condensation to precipitation.
10
Q
HYDROLYSIS
A
A chemical reaction between a mineral and water that results in dissolution of the mineral.
11
Q
HYDROMETER
A
Floating instrument used to measure specific gravity of a liquid.
12
Q
HYDRONIC SYSTEM
A
A re
13
Q
HYDROPHILIC
A
Having an affinity for water.
14
Q
HYDROSTATIC PRESURE
A
The pressure at any point in a liquid at rest
15
Q
Hydroxyl
A
The term used to describe the anionic radical (OH
16
Q
HYGROMETER
A
Instrument used to measure degree of moisture in the atmosphere.
17
Q
HYGROSCOPIC
A
Ability of a substance to absorb and release moisture and change physical dimensions as its moisture content changes.
18
Q
ICE CREAM CABINET
A
Commercial refrigerator which operates at approximately
19
Q
18°C
A
used for storage of ice cream.
20
Q
IGNITION QUALITY
A
The ability of a fuel to ignite when it is injected into the compressed
21
Q
IMMISCIBLE
A
Not capable of mixing (as oil and water).
22
Q
IMPEDANCE (Z)
A
The quantity in an AC circuit that is equivalent to resistance in a DC circuit, inasmuch as it relates current and voltage. It is composed of resistance plus a purely AC
23
Q
IMPELLER
A
A rotating set of vanes designed to impart rotation to a mass of fluid.
24
Q
IMPINGEMENT
A
High
25
INDUCTANCE
The process when a second conductor is placed next to a conductor carrying AC current (but not touching it), the ever
26
INDUCTION
The capture of part of the ambient air by the jet action of the primary air stream discharging from a controlled device.
27
INDUCTION HEATING
Heating by combined electrical resistance and hysteresis losses induced by subjecting a metal to varying magnetic field surrounding a coil carrying alternating
28
INDUCTIVE LOADS
Loads whose voltage and current are out
29
of
phase. True power consumption for inductive loads is calculated by multiplying its voltage, current, and the power
30
INDUCTOR
A fundamental element of electrical systems constructed of numerous turns of wire around a ferromagnetic or air core.
31
INERT GAS
A gas that does not readily enter into or cause chemical reactions.
32
INFILTRATION
Air flowing inward as through a wall, crack, etc.
33
INFLUENT
The solution which enters an ion
34
INHIBITOR
An additive used to retard undesirable chemical action in a product. It is added in small quantities to gasoline’s to prevent oxidation and gum formation, to lubricating oils
35
INORGANIC MATERIAL
Are substances not derived from living things.
36
INRUSH CURRENT
The current that flows the instant after the switch controlling current flow to a load is closed. Also called "locked rotor current".
37
INSTANTANEOUS RATE
Method for determining when load shedding should occur. Actual energy usage is measured and compared to a present kilowatt level. If the actual kilowatt
38
INSULATION, THERMAL
Material which is a poor conductor of heat
39
INSULATOR
A material of such low electrical conductivity that a flow of current through it can usually be neglected. Similarly, a material of low thermal conductivity, such as that used
40
INTERCOOLED CYCLE
Refers to a gas turbine employing two compressors. The compressed air from the first compressor is cooled before being discharged to second compressor.
41
INTERCOOLING
Removal of heat from compressed gas between the compression stages.
42
INTERGRANULAR CRACKING
Cracking or fracturing that occurs between the grains or crystal in a polycrystalline aggregate. Also called intercrystalline cracking. Contrast with
43
INTERMITTENT BLOWDOWN
The blowdown is taken from the mud drum, waterwall headers or the lowest point of circulation.
44
INTERSTAGE DIFFERENTIAL
In a multistage HVAC system, the change in temperature at the thermostat needed to turn additional heating or cooling equipment on.
45
ION
An atom or radical in solution carrying an integral electric charge, either positive (cation) or negative (anion).
46
ION EXCHANGE
A reversible process by which ions are interchanged between solids and a liquid.
47
ION EXCHANGE RESIN
Cross linked polymers that form salts within ions from aqueous solutions.
48
IONIC STRENGTH
A measure of strength of a solution based on both the concentrations and valences of the ions present.
49
IONIZATION
The process of separation of a molecule into its electrically charged atoms or parts.
50
IRON
A metallic element found as an impurity in water in very small amounts. Also a metal which is widely used in the construction of HVAC and plumbing equipment
51
IRON BACTERIA
Are filementous organisms encountered in iron
52
ISENTROPIC PROCESS
A process carried out reversibly without energy interchange as heat. Also a processes carried out with no entropy change.
53
ISOBARIC OR ISOPIESTIC PROCESS
A process carried out at constant pressure.
54
ISOCHORIC PROCESS OR ISOMETRIC
A process during which the specific volume remains constant.
55
ISOMETRIC PROCESS
A process carried out at constant volume.////////////////////////////
56
ISOTHERMAL
Changes of volume or pressure under conditions of constant temperature.
57
ISOTHERMAL EXPANSION AND CONTRACTION
Action which takes place without a temperature change.
58
JET COMPRESSOR
A device employing a ventury tube so that a high pressure stream flowing through the nozzle creates a lower pressure or a vacuum into which the gas to be
59
compressed flows. The gas is discharged from the nozzle with the expanded high
pressure medium.
60
JOULE
English Scientist James Prescott Joule (1818
61
JOULE
The unit used to measure heat, work, and energy in the metric system. Its symbol is J. It is the amount of energy required to move an object of 1 kg mass to a height of 1 m. Also
62
called a newton
metre.
63
JOULE
THOMSON EFFECT
64
JOURNAL
That part of a shaft or axle that rotates relative to a radial bearing.
65
KATA THERMOMETER
Large
66
KELVIN SCALE (K)
Thermometer scale on which unit of measurement equals the Celsius degree and according to which absolute zero is 0 degree, the equivalent of
67
freezes at 273.16 K. and boils at 373.16 K. The relationship
TK = TC + 273.16
68
KEROSINE
a light, hydrocarbon fuel or solvent.
69
KILO CALORIE
This is the amount of heat (energy) necessary to raise the temperature of 1 kg of water 1°C. (Kilo calorie = kcal)
70
KILO CALORIE
This is the amount of heat (energy) necessary to raise the temperature of 1 kg of water 1°C. (Kilo calorie = kcal)
71
KILOGRAIN
A unit of weight
72
KILOVOLT AMPERE
Product of the voltage times the current. Different from kilowatts because of inductive loads in an electrical system. Abbreviated: kVA kilo watts is equal to KVA
73
KILOWATT
A metric unit of power equal to approximately 1.34 horsepower.
74
KILOWATT
HOUR
75
KINETIC ENERGY
The ability of an object to do work by virtue of its motion. (Water moving in a pipe has kinetic energy.) The energy terms that are usually used to describe the
76
KING VALVE
Liquid receiver (refrigeration only) service valve.
77
KIRCHOFF’S SECOND LAW
The law stating that, at each instant of time the increase of voltage around a close loop in a network is equal to the algebraic sum of the voltage drop.
78
KNOCK
In a spark ignition engine, uneven burning of the fuel/air charge that causes violent, explosive combustion and an audible metallic hammering noise. Knock results from
79
KRAFT PROCESS
A wood
80
pulping process in which sodium sulfate is used in the caustic soda pulp
digestion liquor. Also called Kraft pulping or sulfate pulping.
81
kW DEMAND
The maximum rate of electric power usage required to operate a facility during a period of time, usually a month or billing period. Often called "demand".
82
kWh CONSUMPTION
The amount of electric energy used over a period of time
83
LAG
A delay in the effect of a changed condition at one point in the system, on some other condition to which it is related. Also, the delay in action of the sensing element of a control,
84
due to the time required for the sensing element to reach equilibrium with the property being controlled
i.e., temperature lag, flow lag, etc.
85
LAMINAR FLOW
A non
86
LANGELIER SATURATION INDEX
An index (SI) based upon the pH of saturation of calcium carbonate
87
scaling. A positive index indicates scaling tendencies
a negative one means corrosion tendencies. (Langlier Index = pH
88
LATENT HEAT
Change of enthalpy during a change of state, usually expressed in Btu per lb. With pure substances, latent heat is absorbed or rejected at constant pressure.
89
LATENT HEAT
Heat energy absorbed in process of changing form of substance (melting, vaporization, fusion) without change in temperature or pressure.
90
LATENT HEAT OF CONDENSATION
Amount of heat released (lost) by a pound of a substance to change its state from a vapor (gas) to a liquid.
91
LATENT HEAT OF FUSION
The heat required to change 1.0 kg of a substance from the solid to the liquid state.
92
LATENT HEAT OF VAPORIZATION
The energy required to produce saturated vapor from saturated liquid at constant pressure per unit mass of fluid.
93
LAW OF PARTIAL PRESSURE, DALTON’S
Each constituent of a mixture of gases behaves thermodynamically as if it alone occupied the space. The sum of the individual pressures
94
LEADING EDGE
Refers to the point where the steam enters the blade of an impulse turbine.
95
LEAK DETECTOR
Device or instrument such as a halide torch, an electronic sniffer
96
LEAKAGE
In water treatment, it refers to the passing of impure steam or boiler water through the drum internals.
97
LEAKAGE
In water treatment, the phenomenon in which some of the influent ions are not adsorbed and appear in the effluent when a solution is passed through an under regenerated
98
LIGHT CRUDE OIL
A crude oil of relatively high API gravity (usually 40°C degrees or higher).
99
LIGHT EMITTING DIODE
A low current and voltage light used as an indicator on load management equipment. Abbreviated: LED.
100
LIME
A common water treatment chemical.
101
LIME
SODA SOFTENING
102
LINE VOLTAGE
In the control industry, the normal electric supply voltages, which are usually 120 or 240 volts.
103
LIQUEFACTION
The change of state from a gas to a liquid. (The term liquefaction is usually used instead of condensation when referring to substances which are in a gaseous state at
104
LIQUID
Substance whose molecules move freely among themselves, but do not tend to separate like those of gases.
105
LIQUID ABSORBENT
Chemical in liquid form which has the property to "take on" or absorb other fluids. Glycol is such a liquid and widely use in the petroleum chemical industry
106
LIQUID IMPINGEMENT
Material removal due to action of an impingement stream of a fluid.
107
LIQUID INDICATOR
Device located in liquid line which provides a glass window through which liquid flow may be watched.
108
LIQUID LINE
Tube which carries liquid refrigerant from the condenser or liquid receiver to the refrigerant control mechanism.
109
LIQUID LINE CHARGING VALVE
The line used for charging from the high side of the refrigeration system.
110
LIQUID NITROGEN
Nitrogen in liquid form which is used as a low temperature refrigerant in expendable or chemical refrigerating systems.
111
LIQUID PENETRANT INSPECTION
A type of nondestructive inspection that locates discontinuities that are open to the surface of a metal by first allowing a penetrating dye or
112
LIQUID RECEIVER
Cylinder (container) connected to condenser outlet for storage of liquid refrigerant in a system.
113
LIQUID RECEIVER SERVICE VALVE
Two or three
114
LIQUID
VAPOR VALVE REFRIGERANT CYLINDER
115
LIQUOR
Solution used in absorption refrigeration.
116
LITHIUM BROMIDE
A chemical used in combination with water in absorption cooling systems.
117
LOAD
The amount of heat per unit time imposed on a refrigeration system or the required rate of heat removal.
118
LOAD (AIR CONDITIONING)
The amount of heat per unit time imposed on a refrigeration system or the required rate of heat removal.
119
LOAD TURBINE (GAS)
Is the turbine which is directly coupled to the load, which can only be the case with a multishaft gas turbine arrangement.
120
LOCKED ROTOR CURRENT
See "Inrush Current".
121
LONGITUDINAL SEAM
A riveted or welded seam along the longitudinal axis of a boiler shell or drum.
122
LOW SIDE
The refrigerating system from the expansion point to the point where the refrigerant vapor is compressed
123
LOW TEMPERATURE CUTOUT, REFRIGERATON
A pressure or temperature actuated device with sensing element in the evaporator, which will shut the system down at its control
124
LOW VOLTAGE
In the control industry, a power supply of 25 volts or less.
125
LOW
SIDE FLOAT VALVE
126
Refrigerant control valve operated by level of liquid refrigerant in low
pressure side of system.
127
LOW
SIDE PRESSURE
128
LOW
SIDE PRESSURE CONTROL
129
LUBRICANT
A substance
130
LUBRICANT, BONDED FILM
(see lubricant, bonded solid).
131
LUBRICANT, BONDED SOLID
A solid lubricant dispersed in a continuous matrix of a binder or attached to a surface by an adhesive material.
132
LUBRICANT, CHLORINATED
A lubricant containing a chlorine compound that reacts with a rubbing surface at elevated temperatures to protect it from sliding damage, (see extreme
133
LUBRICANT, SYNTHETIC
A lubricant produced by synthesis rather than by extraction or refinement.
134
LUBRICATION, AERODYNAMIC
(see gas lubrication).
135
LUBRICATION, AEROSTATICS
(see pressurized gas lubrication).
136
LUBRICATION, BATH
(see lubrication, flood).
137
LUBRICATION, BOUNDARY
A condition of lubrication in which the friction and wear between two surfaces in relative motion are determined by the properties of the surfaces and by
138
LUBRICATION, DRIP FEED
A system of lubrication in which the lubricant is supplied to the bearing surface in the form of drops at regular intervals.
139
LUBRICATION, DRY FILM
Lubrication that involves the application of a thin film of solid lubricant to the surface or surfaces to be lubricated.
140
LUBRICATION, FLOOD
A system of lubrication in which the lubricant is supplied in a continuos stream at low pressure and subsequently drains away.
141
LUBRICATION, FULL FILM
A type of lubrication wherein the solid surfaces are separated completely by an elstohydrodynamic fluid film.
142
LUBRICATION, MELT
Lubrication provided by steady melting of lubricating species. Also phase
143
LUBRICATION, MIST
Lubrication by an oil mist produced by injecting oil into a gas stream.
144
LUBRICATION, OIL FOG
(see mist lubrication).
145
LUBRICATION, OIL RING
A system of lubrication for horizontal shafts. A ring of larger diameter rotates with the shaft and collects oils from a container beneath.
146
LUBRICATION, PAD
A system of lubrication in which the lubricant is delivered to a bearing surface by a pad of felt or similar material.
147
LUBRICATION, PRESSURIZED GAS
A system of lubrication in which a gaseous lubricant is supplied under sufficient external pressure to separate the opposing surfaces by a gas
148
LUBRICATION, SOLID
FILM
149
LUBRICATION, SPLASH
A system of lubrication in which the lubricant is splashed onto the moving parts.
150
LUBRICATION, THICK FILM
(also known as flood lubrication).
151
LUBRICATION, THIN FILM
(also known as boundary lubrication).
152
LUBRICATION, VAPOR
PHASE
153
LUBRICATION, WASTE
A system of lubrication in which the lubricant is delivered to a bearing surface by cloth waste or yarn.
154
LUBRICATION, WICK
A system of lubrication in which the lubricant is delivered to a bearing surface by means of a wick.
155
LUBRICITY
The ability of a lubricant to reduce wear and friction, other than by its pure viscous properties.
156
MAGNESIUM
A scale forming element found in some boiler feed water.
157
MAGNETIC FIELD
The region within which a body or current experiences magnetic force.
158
MAGNETIC FLUX
The rate of flow of magnetic energy across or through a surface.
159
MAGNETIC IRON OXIDE (Fe3O2)
Partially oxidized iron.
160
MAGNETIC PARTICLE INSPECTION
A nondestructive method of inspection for determining the extent of surface cracks and similar imperfection in ferromagnetic materials.
161
MAGNETIC POLE
The area on a magnetized part at which the magnetic field leaves or enters the part. It is the point of maximum attraction in a magnet.
162
MAGNETIC REFRIGERATION
Where very low temperatures are obtained by using paramagnetic salts with magnets.
163
MAKEUP WATER
Water fed to a system to replace that which is lost
164
for example, water fed to a boiler to replace that lost as steam or condensate
water fed to a cooling tower to
165
MALLEABILITY
The characteristic of metals that permits plastic deformation in compression without fracture.
166
MANGANESE
A metallic element occasionally found in very small amounts as an impurity in well
167
MANIFOLD, SERVICE
Chamber equipped with gauges and manual valves, used by service technicians to service refrigerating systems.
168
MANIFOLDING
A method of circulating the refrigerant through separate rows of tubes and mostly used with direct
169
MANOMETER
A device to measure small to moderate pressure differentials. Device is general constructed from glass or plastic tubes filled with water, oil, alcohol or other suitable
170
MANOMETER
An instrument for measuring pressures: especially a U
171
MANUAL FROST CONTROL
Manual control used to change operation of refrigerating system to produce defrosting conditions.
172
MASS
The quantity of matter in a body as measured by the ratio of the force required to produce a given acceleration, to the acceleration.
173
MASTER (CENTRAL) CONTROL
Control of all outlets from one point.
174
MCM
Thousand circular mill used to describe large wire sizes.
175
MECHANICAL SEALS
A mechanical device used to control leakage from the stuffing box of a pump. Mechanical seals are usually made of two flat surfaces, one of which rotates on a
176
MECHANICAL WEAR
Removal of material due to mechanical process under conditions of sliding, rolling, or repeated impact. Included are abrasive wear, fatigue wear and adhesive
177
MELTING POINT
For a given pressure, the temperature at which the solid and liquid phases of the substance are in equilibrium.
178
MELTING POINT
Temperature at atmospheric pressure at which a substance will melt.
179
MEMBRANE
A barrier, usually thin, that permits the passage only of particles up to a certain size or of special nature.
180
MEMBRANE
A thin sheet or layer.
181
MERCAPTAN
A compound chemically similar to alcohol, with sulfur replacing the oxygen in the chemical structure. Many mercaptans have an offensive odor and are used as
182
METALLURGICAL FACTOR
The condition of the metal, such as inclusions, chemical segregation’s, cold work and others, which have an impact upon the rate of electrochemical
183
MICA
A silicate material used with high pressure gauge glasses on boilers.
184
MICROBAR
A unit of pressure equal to 1 dyne/cm2 (one millionth of the pressure of the atmosphere).
185
MICROFILTRATION
A membrane filtration process, which forces water through a porous barrier. Pores are usually between 0.1 to 20 m m, when used for water purification. For filtering
186
Micron
A unit of length, the thousandth part of 1 mm of the millionth of a meter.
187
Microprocessor
A small computer used in load management to analyze energy demand and consumption such that loads are turned on and off according to a predetermined program.
188
MILD STEEL
A low
189
MILL SCALE
A natural black iron oxide coating loosely adhering to the interior of new piping or tubes.
190
MINERAL
A naturally occurring inorganic substance having specified chemical composition and crystalline structure.
191
MISCIBILITY
The ability of two liquids, not mutually soluble, to mix.
192
MIX BED DEMINERALIZER
Having a mixture of cation and anion exchange resin in the same housing.
193
MIXTURE
A physical blend of two or more substances.
194
MODULATING
Type of device or control which tends to adjust by increments (minute changes) rather than by either "full on" or "full off" operation.
195
MODULATING CONTROL
A mode of automatic control in which the action of the final control element is proportional to the deviation, from set point, of the controlled medium.
196
MODULATING REFRIGERATION CYCLE
Refrigerating system of variable capacity.
197
MODULUS OF ELASTICITY (E)
The measure of rigidity or stiffness of a material.
198
MOISTURE INDICATOR
Instrument used to measure moisture content of a refrigerant.
199
MOLLIER DIAGRAM
An enthalpy
200
entropy or enthalpy
pressure chart showing the thermodynamic properties of a fluid.
201
MONOMER
A molecule, usually an organic compound, having the ability to join with a number of identical molecules to form a polymer.
202
MOTOER CONTROL CENTER
A single metal enclosed assembly containing a number of motor controllers and possibly other devices such as switches and control devices.
203
MUD DRUM
A pressure chamber of a drum or header type located at the lower extremity of a water tube boiler and fitted with blowoff valve.
204
MULLION HEATER
Electrical heating element mounted in the mullion. Used to keep mullion from sweating or frosting.
205
MULTIPLE STAGE COMPRESSOR
Compressor having two or more compressive steps. Discharge from each step is the intake pressure of the next in series.
206
MULTIPLE SYSTEM
Refrigerating mechanism in which several evaporators are connected to one condensing unit.
207
MULTI
SHAT GAS TURBINE
208
MULTISTAGE COMPRESSION REFRIGERATION SYSTEM
Where the refrigerant is vaporized and condensed alternately and is compressed in the vapor phase.
209
MULTISTAGE THERMOSTAT
A thermostat which controls auxiliary equipment for heating or cooling in response to a greater demand for heating or cooling.
210
NAPHTA
A volatile, flammable liquid hydrocarbon distilled from petroleum and used as a solvent or fuel.
211
NATURAL CIRCULATION
The circulation of a boiler caused by differences in density. Also referred as thermal or thermally induced circulation.
212
NATURAL CONVECTION
Movement of a fluid caused only by temperature differences (density changes).
213
NATURAL DRAFT COOLING TOWER
Cools water by moving air at low velocities.
214
NATURAL GAS
A highly compressible, highly expandable mixture of hydrocarbons having a low specific gravity and occurring naturally in gaseous form. Besides hydrocarbon gases,
215
NATURALLY ASPIRATED
A term used to describe a diesel engine in which air flows into the engine by means of atmospheric pressure only.
216
NC
Normally closed contacts of a relay.
217
NEGATIVE CHARGE
The electrical potential which an atom acquires when it gains one or more electrons
218
NET POSITIVE SUCTION
The difference between total pressure and vapor pressure in a fluid flow, expressed in terms of equivalent height or "head".
219
NEUTRAL
The circuit conductor that is normally grounded or at zero voltage difference to the ground.
220
NEUTRALIZATION NUMBER
An ASTM number given to quenching oils that reflect the oil’s tendency toward oxidation and sludging.
221
NEUTRALIZER
A substance that will combine with an acid or alkali chemically, thus removing the acidity or alkalinity.
222
NEUTRALIZING AMINES
Are amines used to neutralize the acid generated by the dissolution of carbon dioxide.
223
NEWTON
The unit of force in the metric system. A newton is the force required to accelerate an object of 1 kilogram mass to a velocity of 1 meter per second in 1 second.
224
NIPPLE
A short, threaded tubular coupling, used for making connections between pipe joints.
225
NITROGEN BLANKETING
Used with wet standby, where the space above the water level is filled with nitrogen at about 5 to 10 psig in order to keep the oxygen out.
226
NITROGEN DIOXIDE
Mildly poisonous gas (NO2) often found in smog or automobile exhaust
227
NO
Normally open contacts of a relay.
228
NOBEL METAL
A chemically inactive metal, such as gold.
229
NO
FROST FREEZER
230
Low
temperature refrigerator cabinet in which no frost or ice collects on freezer surfaces or materials stored in cabinet.
231
NOISE
Any undesired sounds, usually of different frequencies, resulting in an objectionable or irritating sensation.
232
NOMINAL SIZE
A designated size that may be different from the actual size.
233
NOMINAL SIZE TUBING
Tubing measurement which has an inside diameter the same as iron pipe of the same stated size.
234
NON
CARBONATED HARDNESS
235
NON
CODE INSTALLATION
236
NON
CONDENSABLES
237
NON
DESTRUCTIVE INSPECTION (NDI)
238
NON
FERROUS ALLOY
239
NON
FROSTING EVAPORATOR
240
NON
MECHANICAL REFRIGERATION
241
NON
REACTIVE SILICA
242
Is a polymeric form of silica
thermally unstable which reverts to normal silica when heated. Difficult to detect, but may be present when boiler feedwater
243
NORMAL CARRYOVER
Refers to the carryover which occurs in any boiler operating under the best conditions.
244
NORMAL CHARGE
Thermal element charge which is part liquid and part gas under all operating conditions.
245
NORMALLY OPEN
(OR NORMALYCLOSED) The position of a valve, damper, relay contacts, or switch when external power or pressure is not being applied to the device. Valves
246
NTU
Nephelometric turbidity unit. A light
247
NUCLEATE BOILING
The even boiling of water in which steam bubbles are formed within the boiler water gradually and are evenly distributed rather than being suddenly formed and
248
OCCLUSION
An absorption process by which one solid material adheres strongly to another, sometimes occurring by coprecipitation.
249
OCTANE RATING
A classification of gasoline according to its antiknock qualities. The higher the octane number or rating, the greater are the antiknock qualities of the gasoline.
250
OCTYL ALCOHOL
ETHYL HEXANOL
251
OFFSET
Term used to describe the difference between the set point and the actual operating or control point.
252
OHM
The unit of electrical resistance equal to the resistance through which a current of 1 ampere will flow when there is potential difference of one volt across it.
253
OHM’S LAW
The relationship between current and voltage in a circuit. It states that current is proportional to voltage and inversely proportional to resistance. Expressed algebraically,
254
in DC circuits I=E/R
in AC circuits I=E/Z.
255
OIL
A liquid of vegetable, animal, mineral, or synthetic origin that feels slippery to the touch.
256
OIL BINDING
Condition in which an oil layer on top of refrigerant liquid may prevent if from evaporating at its normal pressure temperature.
257
OIL GROOVE
A channel or channels in a bearing to improve oil flow through the bearing.
258
OIL RING LUBRICATION
A system of lubrication for horizontal shafts. A ring of larger diameter rotates with the shaft and collects oils from a container below.
259
OIL SEPARATOR
Device used to remove oil from gaseous refrigerant or steam.
260
OIL, MINERAL
A refined hydrocarbon oil without animal or vegetable additives.
261
OIL, MULTIGRADE
An oil having relative little change in viscosity over a specified temperature range.
262
OIL, NEUTRAL
A lubricating oil obtained by distillation, not treated with acid or with alkali.
263
OIL, TURBINE
An oil used to lubricate bearings in a steam or gas turbine.
264
ONCE
THROUGH BOILER
265
A steam generating unit usually operated above the critical pressure in which there is no re
circulation of the working fluid in any part of the unit.
266
ON
OFF CONTROL
267
OPEN CIRCUIT
The absence of a direct connection between two points in an electrical network.
268
OPEN CYCLE
A gas turbine arrangement, in were the exhaust gases from the turbine are exhausted to the atmosphere without any further treatment.
269
OPEN RE
CIRCULATING WATER SYSTEM
270
A system, using continuously circulated water as a heat
transfer medium, in which the water is exposed at one point to the atmosphere for
271
OPERATING POINT
The value of the controlled condition at which the controller actually operates. Also called control point.
272
OPERATING PRESSURE
Actual pressure at which the system works under normal conditions. This pressure may be positive or negative (vacuum).
273
ORGANIC GROWTH
A substance resulting from the growth of biological organisms such as fungi, algae, and slime bacteria.
274
ORGANIC MATERIAL
Contain carbon and usually hydrogen and are derived from living things.
275
ORGANIC OXYGEN SCAVENGERS
These are organic compounds such as hydroquinone and ascorbate to remove dissolved oxygen from the boiler feedwater and condensate.
276
ORIFICE
Accurate size opening for controlling fluid flow.
277
ORSAT ANALYZER
A furnace atmosphere analysis device in which gases are absorbed selectively (volumetric basis) by passing them through a series of pre
278
OSHA
Occupational Safety and Health Administration.
279
OSMOSIS
The passage of water through permeable membrane separating two solutions of different concentration
280
OUTSIDE AIR OPENING (HVAC)
Any opening used as an entry for air from outdoors.
281
OVERCURRENT DEVICE
A device such as a fuse or a circuit breaker designed to protect a circuit against excessive current by opening the circuit.
282
OVERFLOW PIPE
A pipe installed at a top of a tank to enable the liquid within to be discharged to another vessel when the tank is filled to capacity.
283
OVERLOAD
A condition of excess current
284
OVERRIDE
A manual or automatic action taken to by pass the normal operation of a device or system
285
OXIDATION
The reaction of an element or substance with oxygen, e.g., iron is oxidized by reaction with oxygen to form rust (iron oxide).
286
OXIDIZING AGENT
Any substance such as oxygen, or chlorine, that will readily add (take on) electrons.
287
OXIDIZING ATMOSPHERE
A furnace atmosphere with an oversupply of oxygen that tends to oxidize materials placed in it.
288
OXIDIZING BIOCIDE
An agent, such as chlorine, which will kill bacteria by the chemical process of oxidation.
289
OXYACETYLENE WELDING
An oxyfuel gas welding process in which the fuel gas is acetylene.
290
OXYGEN CONCENTRATION CELL
(see differential aeration cell).
291
OXYGEN CONCENTRATION CELL
The surface area in contact with the media of higher oxygen concentration becomes the cathodic area, and the area with the lower oxygen
292
OXYGEN PITTING
Damage caused due to the presence of oxygen in the feedwater. Damage results are small pit
293
OXYGEN SCAVENGER
A substance that will absorb oxygen by chemical reaction.
294
OZONE
Triatomic oxygen (03). Sometimes used in cold storage or air conditioning installations as an odor eliminator. Can be toxic in certain concentrations.
295
PACKAGE UNITS, (REFRIGERATION)
Complete refrigerating system including compressor, condenser and evaporator located in the refrigerated space.
296
PACKED COLUMN
A tower filled with small objects, designed to obtain large surfaces per volume between rising vapors and a descending liquid.
297
PACKING
Material made usually of woven animal, plant, mineral or metal fiber and some type of lubricant, placed in rings around the shaft of a pump and used to control leakage from
298
PACKING
The fill in a confined space in a stripping vessel, ranging from simple shaped units such as rocks or slats to complex shapes that provide large surface area per unit volume.
299
PACKING GLAND
The metal part that compresses and holds packing in place in a stuffing box.
300
PARALLEL CIRCUIT
One where all the elements are connected across the voltage source. Therefore, the voltage on each element is the same but the current through each may be
301
PARTIAL PRESSURES
Condition where two or more gases occupy a space and each one creates part of the total pressure.
302
PASCAL
The accepted metric unit of measurement or pressure and stress component in the measurement of viscosity. A Pascal is equal to a force of 1 Newton acting an area of 1
303
PASCAL'S LAW
Pressure imposed upon a fluid is transmitted equally in all directions.
304
PASSIVATING (ANODIC) INHIBITORS
A material capable of forming a protective oxide film on metal surfaces.
305
PASSIVATION
The process of rendering a metal surface chemically inactive, either by electrochemical polarization or by contact with a passivating agent.
306
PASSIVATOR
A type of corrosion inhibitor that appreciably changes the potential of a metal to a more noble (positive) value.
307
PASSIVATOR
A type of corrosion inhibitor that appreciably changes the potential of a metal to a more positive value.
308
PASSIVE
ACTIVE CELL
309
PASSIVITY
A condition on metal surfaces that inhibits electrochemical action between the metal and its environment, such as with boiler water.
310
PATHOGENIC BACTERIA
Disease
311
PEAK DEMAND
The greatest amount of kilowatts needed during a demand interval.
312
PEAK LOAD PRICING
A pricing principle that charges more for purchases that contribute to the peak demand and, thereby, cause the expansion of productive capacity when the peak
313
utility or on or near the daily peak of the utility. The latter requires special meters
the former does not.
314
PEAKING LOAD
Is the electrical load drawn on the system during high power usage. Usually on very hot or cold days or during the supper hour.
315
PELTIER EFFECT
When direct current is passed through two adjacent metals one junction will become cooler and the other will become warmer. This principle is the basis of
316
PERFECT GAS
A hypothetical gas obeying the relation pv = RT.
317
PERMANENT GASES
Cryogenic refrigerants.
318
PERMEABILITY
The ability of a body to pass fluid under pressure.
319
PETROLEUM OIL
(see mineral oils).
320
pH
The negative logarithm of the hydrogen
321
ion concentration of a solution
simply a measure of the relative acidity or alkalinity of a water solution. (pH 1 very acidic
322
pH OF SATURATION (pHs)
The pH at which a sample of water is saturated with a specific salt
323
PHASE
Part of an AC voltage cycle. Residential electrical service is 2
324
phase
commercial facilities are usually 3
325
PHIAL
Term sometimes used to denote the sensing element on a thermostatic expansion valve.
326
PHOSPHATE
An ion, compound, or salt containing phosphorus and oxygen, such as sodium phosphate (Na3P04).
327
PHOSPHATE TREATMENT
An internal boiler water treatment method to reduce calcium in the boiler with low hardness feedwater.
328
PHYSICAL STABILITY
The quality which an ion
329
PHYSICAL WATER TREATMENT
Refers to the treatment of removing dissolved gases from the boiler feedwater, using steam.
330
PIG IRON
High
331
PILOT DUTY RELAY
A relay used for switching loads such as another relay or solenoid valve coils. The pilot duty relay contacts are located in a second control circuit. Pilot duty
332
relays are rated in volt
amperes (VA).
333
PIPE SCALE
Rust or mill scale found on the interior of water pipe.
334
PIT
Corrosion localized in a small spot.
335
PITOTE TUBE
An open ended tube arrangement to face against the current of a stream of fluid
336
PITS
Petroleum Industry Training Service. (Canada)
337
PITTING
Localized corrosion of a metal characterized by small blisters under which holes have perforated the metal.
338
PLASTICITY
The ability of a substance to be deformed without rupturing.
339
PLENUM CHAMBeR
An air compartment connected to one or more distributing ducts.
340
PLENUM CHAMBER
Chamber or container for moving air or other gas under a slight positive pressure.
341
PNEUMATIC
Operated by air pressure.
342
PNEUMATIC
ELECTRIC (PE) SWITCHES
343
pOH
An expression of the alkalinity of a solution
344
the negative logarithm of the hydroxyl
ion concentration.
345
POINT, CRITICAL
Of a substance, state point at which liquid and vapor have identical properties
346
POLARITY
The direction of current flow in a DC circuit. By convention, current flows from plus to minus. Electron flow is actually in the opposite direction.
347
POLARIZE
In corrosion, to develop a barrier on the anodic or cathodic surface, disrupting the corrosion process.
348
POLE
An electrical connection point. In a panel, the point of connection. On a device, the terminal that connects to the power.
349
POLYELECTROLYTE
A water
350
POLYMER
A chemical compound formed by the adjoining of many molecules of the same characteristics
351
POLYMERIC DISPERSANT
A water
352
soluble polymer that acts as a suspending agent
that is, it promotes suspension of particles in water so that they resist settling.
353
POLYPHOSPHATE
A chemical compound formed by the adjoining of phosphate ions, hence a polymer of phosphate.
354
POLYTHROPIC PROCESS
A nonadiabatic reversible process characterized by the equation of path, pv = constant.
355
POROUS VASE
A vase having a porous construction, which was used to cool its content.
356
POSITIVE CHARGE
The electrical potential acquired by an atom which has lost one or more electrons
357
POTENTIAL ENERGY
The energy, that a body has by virtue of its position or state, enabling it to do work. (Water in a reservoir has potential energy by virtue of its elevation above
358
POTENTIAL TRANSFORMER
A voltage transformer. The voltage supplied to a primary coil induces a voltage in a secondary coil according, to the ratio of the wire windings in each
359
POTENTIOMETER
An electromechanical device having a terminal connected to each and to the resistive element, and a third terminal connected to the wiper contact. The electrical
360
POUR POINT
The lowest temperature at which a lubricant can be observed to flow under specified conditions. For oil, the pour point is a temperature
361
POUR
POINT DEPRESSANT
362
POWER (P)
Expressed in watts (W) or kilowatts (kW), and is equal to:
363
POWER ELEMENT
Sensitive element of a temperature
364
POWER FACTOR (pf)
A quantity that relates the volt amperes of an AC circuit to the wattage (power = volt
365
POWER FACTOR CHARGE
A utility charge for "poor" power factor. It is more expensive to provide power to a facility with a poor power factor (usually less than 0.8).
366
POWER FACTOR CORRECTION
Installing capacitors on the utility service’s supply line to improve the power factor of the building.
367
ppb
equals 0.001 ppm. (Parts per billion)
368
PRECIPITATE
An insoluble reaction product
369
PRECIPITATING (CATHODIC) INHIBITORS
The are chemicals which form insoluble precipitates that are able to coat and protect surfaces. They are less durable then the passivating
370
PRECIPITATION
A process whereby salts drop or come out of a water solution.
371
PRECISION PHOSPHATE TREATMENT
A phosphate treatment based upon maintaining 2 to 4 ppm of phosphate and 15 to 50 ppm of hydrate alkalinity in the boiler.
372
PREDICTING METHOD
A method for determining when load shedding should occur. A formula is used to arrive at a preset kilowatt limit. Then the actual amount of energy
373
PREIGNITION
A condition in an internal combustion engine characterized by a knocking sound and caused by the fuel
374
PRESSURE
The normal force exerted by a homogeneous liquid or gas, per unit of area, on the wall of its container.
375
PRESSURE DROP
Pressure loss in fluid pressure, as from one end of a duct or pipe to the other, due to friction, dynamic losses, and changes in velocity pressure.
376
PRESSURE GAUGE
Instrument for measuring the pressure exerted by the contents on its container.
377
PRESSURE HEAD
The height to which liquid can be raised by a given pressure (sometimes referred to as pump head).
378
PRESSURE MOTOR CONTROL
Device which opens and closes an electrical circuit as pressures change.
379
PRESSURE OPERATED THERMOMETER
Temperature indicator which is controlled by bellows, a capillary or remote sensitive bulb.
380
PRESSURE REGULATOR, SUCTION (REFRI
GERATION COMPRESSORS)
381
PRESSURE SWITCH
Switch operated by a rise or drop in pressure.
382
PRESSURE VELOCITY
In moving fluid, the pressure capable of causing an equivalent velocity, if applied to move the same fluid through an orifice such that all pressure energy
383
PRESSURE, ABSOLUTE
Pressure referred to that of a perfect vacuum. It is the sum of gauge pressure and atmospheric pressure.
384
PRESSURE, ATMOSPHERIC
It is the pressure indicated by a barometer. Standard atmosphere is the pressure equivalent/////////
385
PRESSURE, CRITICAL
Vapor pressure corresponding to the substance's critical state at which the liquid and vapor have identical properties.
386
PRESSURE, GAGE
Gauge: Pressure above atmospheric.
387
PRESSURE, HYDROSTATIC
The normal force per unit area that would be exerted by a moving fluid on an infinitesimally small body immersed in it if the body were carried along with
388
PRESSURE, OPERATING
Pressure at which a system is operating.
389
PRESSURE, PARTIAL
Portion of total gas pressure of a mixture attributable to one component.
390
PRESSURE, SATURATION
The saturation pressure for a pure substance for any given temperature is that pressure at which vapor and liquid, or vapor and solid, can coexist in stable
391
PRESSURE, STATIC
The normal force per unit area that would be exerted by a moving fluid on a small body immersed in it if the body were carried along with the fluid. Practically, it is
392
PRESSURE, TOTAL
In the theory of the flow of fluids, the sum of the static pressure and the velocity pressure at the point of measurement. Also called dynamic pressure.
393
PRESSURE, VAPOR
The partial pressure exerted by the water vapor contained in air.
394
PRESSURE
HEAT DIAGRAM
395
PRESSURESTAT
A control which reacts to pressure changes in the evaporator.
396
PRESSURE
VELOCITY COMPOUNDING
397
PRETREATMENT
Also referred to as external treatment, consisting of treating the raw make
398
PRIMARY AIR
The initial air stream discharged by an air outlet (the air being supplied by a fan or supply duct) prior to any entrainment of the ambient air or for he purpose of
399
PRIMARY CONSTITUENTS
Refers to the category of dissolved solids present in water at a level of more then 5 mg/L.
400
PRIMARY CONTROL
A device which directly or indirectly controls the control agent in response to needs indicated by the controller. Typically a motor, valve, relay, etc.
401
PRIMARY ELEMENT
The portion of the controller which first uses energy derived from the controlled medium to produce a condition representing the value of the controlled variable
402
PRIMARY SYSTEM
A closed water system in which the water is circulated directly through a chiller for cooling or heat exchanger or boiler for heating.
403
PRIME MOVER
An engine or other device by which natural source of energy is converted into mechanical energy.
404
PRIMING
The phenomenon in which the level of water in a boiler is changed by bouncing rapidly. The result is, that boiler water will enter the steam flow.
405
PROCESS HOT WATER
Hot water needed for manufacturing processes over and above the "domestic hot water" that is for the personal use of industrial workers.
406
PROPANE
A paraffin hydrocarbon (C3H8) that is a gas at ordinary atmospheric conditions but easily liquefied under pressure.
407
PROPORTIONAL BAND
The range of values of a proportional positioning controller through which the controlled variable must pass to move the final control element through its full
408
PSI
Symbol or initials used to indicate pressure measured in pounds per square inch.
409
PSIA
Symbol or initials used to indicate pressure measured in pounds per square inch absolute. Absolute pressure equals gauge pressure plus atmospheric pressure. The "A" indicates
410
PSIG
Symbol or initials used to indicate pressure in pounds per square inch gauge. The "G" indicates that is gauge pressure and not absolute pressure.
411
PSYCHROMETER
An instrument for ascertaining the humidity or hygrometric state of the atmosphere.
412
PSYCHROMETRIC MEASUREMENT
Measurement of temperature pressure and humidity using a psychometric chart.
413
PSYCHROMETRY
The study of air
414
PULL DOWN
An expression indicating action of removing refrigerant from all or part of a refrigeration system.
415
PULSATION DAMPENER
Any gas or liquid charged, chambered device that minimizes periodic increases and decreases in pressure.
416
PULSE
ECHO TECHNIQUES
417
PUMP
A device that increases the pressure on a fluid or raises it to a higher level.
418
PUMP DOWN
The act of using a compressor or a pump to reduce the pressure in a container or a system.
419
PUMP, POSITIVE DISPLACEMENT
A pump that moves a measured quantity of fluid with each stroke of a piston or each revolution of vanes or gears.
420
PUMP, ROTARY
A pump that moves fluid by positive displacement, using a system of rotating vanes, gears, or lobes.
421
PUMP
DISCHARGE PRESSURE
422
The point of highest pressure in a re
circulating water system which is at the discharge side of the re
423
PURGING
Releasing compressed gas to atmosphere through some part or parts for the purpose of removing contaminants from that part or parts.
424
PURGING VALVES
Devices used to remove non
425
PYROMETER
A device for measuring temperatures above the range of liquid thermometers.
426
QUALITY
Weight fraction of the vapor in a vapor
427
QUICKLIME
Unslaked lime (calcium oxide).
428
RACEWAY
Any support system, open or closed, for carrying electric wires.
429
RADIANT HEATING
Heating system in which warm or hot surfaces are used to radiate heat into the space to be conditioned.
430
RADIATION
Transfer of heat by electromagnetic waves.
431
RAM AIR
Air forced through the condenser due to the rapid movement of steam from the turbine exit.
432
RANKINE SCALE
Name given the absolute (Fahrenheit) scale. Zero (0) R on this scale is
433
RANKINE TEMPERATURE
Degrees Fahrenheit plus 491.60.
434
RAPTURE MEMBRANE
A metal membrane (pressure relief device) designed to rapture at a predetermined pressure.
435
RAW MAKEUP WATER
Untreated water fed to a system to replace that lost.
436
RAW WATER
With water treatment it means untreated feedwater or water in its natural state, prior to any treatment.
437
REAGENT
A substance, chemical, or solution used in laboratory to detect, measure, or react with other substances, chemicals or solutions.
438
RE
CARBONATION
439
A process using carbon dioxide gas to stabilize and thereby prevent precipitation of calcium carbonate from cold process lime or lime
soda softened water.
440
RECEIVER
An auxiliary storage receptacle for fluids.
441
RECEIVER DEHYDRATOR
Small tank which serves as liquid refrigerants reservoir and which also contains a desiccant so remove moisture. Used on most automobile air conditioning
442
RECEIVER HEATING ELEMENT
Electrical resistance mounted in or around liquid receiver. It is used to maintain head pressures when ambient temperature is low.
443
RECEIVER
DRIER
444
RECIPROCAL
A format defined by 1 divided by the complex number.
445
RECIPROCATING COMPRESSOR
Compressor which uses a piston and cylinder mechanism to provide pumping action.
446
RECORDING THERMOMETER
Temperature measuring instrument which has a pen marking a moving chart.
447
RECTIFIER
A device used to convert AC current into DC current.
448
RECUPERATOR
Equipment for transferring heat from gaseous products of combustion to incoming air or fuel. The incoming material passes through pipes surrounded by a chamber
449
RED WATER
Water that has a red, cloudy appearance caused by suspended red iron oxide.
450
REDOX POTENTIAL
A process designed to determine if a corrosion process will occur.
451
REDUCING ELBOW
A fitting that makes an angle between two joints of pipe and that decreases in diameter from one end to the other.
452
REDUCING FLANGE
A flange fitting used to join pipes of different diameters.
453
REDUCING NIPPLE
A pipe fitting that is threaded on both ends and decreases in diameter from one end to the other.
454
REDUCING TEE
A "T"shaped pipe fitting with openings of two different sizes. The relationship:
455
REDUCTION
Reduction is the addition of hydrogen, removal of oxygen, or the addition of electrons to an element or compound.
456
REED VALVE
Thin, flat, tempered steel plate fastened at one end.
457
REFRIGERANT
The fluid used for heat transfer in a refrigerating system, which absorbs heat at a low temperature and a low pressure of the fluid and rejects heat at a higher
458
REFRIGERANT
The working fluid used in refrigerators.
459
REFRIGERANT CHARGE
Quantity of refrigerant in a system.
460
REFRIGERANT CONTROL
Device which meters flow of refrigerant between two areas of a refrigerating system. It also maintains pressure difference between high
461
low
pressure side of the mechanical refrigerating system while unit is running.
462
REFRIGERATING CAPACITY
The ability of a system to remove heat as compared with the cooling effect produced by melting of ice.
463
REFRIGERATING EFFECT
The amount of heat transferred by one kg of refrigerant as it circulates in the refrigeration system.
464
REFRIGERATION
Controlled transfer of heat from a lower temperature to a higher temperature region.
465
REFRIGERATION OIL
Specially prepared oil used in refrigerator mechanism which circulates, to some extent, with refrigerant.
466
REFRIGERATOR
A device to transfer heat from a low temperature to a high temperature medium.
467
REGENERANT
The solution used to restore the activity of an ion exchanger. Acids are employed to restore a cation exchanger to its hydrogen form
468
REGENERATION
Restoration of the activity of an ion exchanger by replacing the ions adsorbed from the treated solution by ions that were adsorbed initially on the resin.
469
REGENERATIVE CYCLE
Is a gas turbine cycle employing a heat exchanger to recover some of the heat before discharging the gases from the gas turbine to the atmosphere, to recover
470
REGENERATIVE GAS TURBINE
Referring to a gas turbine employing heat exchanger between the compressor and the combustor for the purpose of recovering heat.
471
REJUVENATION
(see regeneration)
472
RELATIVE HUMIDITY
The amount of moisture the air holds relative to the maximum moisture the air can hold at the same temperature.
473
RELATIVE HUMIDITY
The ratio, expressed as a percentage, of the amount of water vapor present in a given volume of air at a given temperature to the amount required to saturate the
474
RELAY
An electromechanical switch that opens or closes contacts in response to some controlled action. Relay contacts can be normally open (NO) and/ or normally closed (NC).
475
RELAY, THERMAL
A switching relay in which a small heater warms a bimetal element which bends to provide the switching force.
476
RELIEF VALVE
Safety device on a sealed system. It opens to release fluids before dangerous pressure is reached. Also called pressure relief valve.
477
REMOTE SYSTEM
Refrigerating system in which condensing unit is away from space to be cooled.
478
RESET
A process of automatically adjusting the control point of a given controller to compensate for changes in outdoor temperature. The hot deck control point is normally reset
479
RESET RATIO
The ratio of change in outdoor temperature to the change in control point temperature. For example, a 2:1 reset ratio means that the control point will increase 1 degree
480
RESIDUAL
Means small amount of, like oxygen, sulfite, acid., etc..
481
RESISTANCE
The opposition which limits the amount of current that can be produced by an applied voltage in an electrical circuit, measured in ohms.
482
RESISTANCE, THERMAL
The reciprocal of thermal conductance.
483
RESISTIVE LOADS
Electrical loads whose power factor is one. Usually contain heating elements.
484
RESTRICTOR
A device for producing a deliberate pressure drop or resistance in a line by reducing the cross
485
RETURN
STEAM CONDENSATE
486
REVERSE CYCLE DEFROST
Method of heating evaporator for defrosting. Valves move hot gas from compressor into evaporator.
487
REVERSE CYCLE REFRIGERATION
A refrigeration system which uses reject heat to produce warmth.
488
REVERSE DEIONIZATION
The use of an anion
489
exchange unit and a cation
exchange unit
490
in that order
to remove all ions from solution.
491
REVERSE OSMOSIS
A process that reverses (by the application of pressure) the flow of water in the natural process of osmosis so that it passes from the more concentrated to the
492
REVERSIBLE PROCESS
A process by which a fluid is made to undergo a change of state and by traversing the path in exactly the reverse of the original path is returned to its original
493
REVERSING VALVE
Device used to reverse direction of the refrigerant flow depending upon whether heating or cooling is desired.
494
RINSE
The operation which follows regeneration
495
ROTARY COMPRESSOR
Mechanism which pumps fluid by using rotating motion.
496
RROSION, SELECTIVE
The selective corrosion of one or more components of a solid solution alloy.
497
RUNNING CURRENT
The current that flows through a load after inrush current. Usually called "full load current".
498
RUNNING TIME
Amount of time a condensing unit is run per hour or per 24 hours.
499
RUST
A visible corrosion product consisting of hydrated oxides of iron. Applied only to ferrous alloys.
500
RYZNAR STABILITY INDEX
An index based on calcium carbonate pH of saturation vs. actual pH to determine scaling or corrosion tendencies of a water (R.I. = 2 pHs).
