All Terms Flashcards
ABRASION
The wearing away of a surface by rubbing, as with sandpaper on wood.
ABRASION RESISTANCE
The ability of a material to resist surface wear.
ABRASIVE EROSION
Erosive wear caused by the relative motion of solid particles which are entrained in a fluid, moving nearly parallel to a solid surface.
ABSOLUTE HUMIDITY
Amount of moisture in the air, indicated in kg/kg of dry air.
ABSOLUTE PRESSURE
Total pressure measured from an absolute vacuum. It equals the sum of the gauge pressure and the atmospheric pressure corresponding to the barometer.
ABSOLUTE PRESSURE
Air at standard conditions (70°F air at sea level with a barometric pressure of 29.92 in Hg) exerts a pressure of 14.696 psi. This is the pressure in a system when the pressure gauge reads zero. So the absolute pressure of a system is the gauge pressure in pounds per square inch added to the atmospheric pressure of 14.696 psi (use 14.7 psi in environmental system work) and the symbol is “psia”.
ABSOLUTE TEMPERATURE SCALE
A scale of temperature measurement in which zero degrees is absolute zero.
ABSOLUTE ZERO
A hypothetical temperature at which there is total absence of heat. Since heat is a result of energy caused by molecular motion, there is no motion of molecules with
ABSOLUTE ZERO TEMPERATURE
Temperature measured from absolute zero (
ABSORBENT
A material which, due to an affinity for certain substances, extracts one or more such substances from a liquid or gaseous medium with which it contacts and which changes physically or chemically, or both, during the process. Calcium chloride is an example of a solid absorbent, while solutions of lithium chloride, lithium bromide, and ethylene glycols are liquid absorbents.
ABSORBER
That part of the low side of an absorption system, used for absorbing vapor refrigerant.
ABSORPTION
A process whereby a material extracts one or more substances present in an atmosphere or mixture of gases or liquids accompanied by the material’s physical and/or chemical changes.
ABSORPTION TOWER
A tower or column, which effects contact between a rising gas and a falling liquid, so that part of the gas may be taken up by the liquid.
ACCELERATION
The rate of change of velocity, as a function of time. Expressed in m/s.
ACCELERATION DUE TO GRAVITY
The rate of increase in velocity of a body falling freely in a vacuum. Its value varies with latitude and elevation. The International Standard is 9.81 m/s^2
ACCEPTABLE WELD
A weld that meets all of the requirements and the acceptance criteria prescribed by the welding specifications.
ACCESSIBLE HERMETIC
An assembly of motor and compressor, inside a single bolted housing unit.
ACCUMULATOR
Storage tank which receives liquid refrigerant from evaporator and prevents it from flowing into suction line before vaporizing.
ACETONE
A filler added to acetylene cylinders, capable of absorbing 25 times its own volume of acetylene.
ACID
Literally hitter, but chemically the state of a water solution containing a high concentration of hydrogen ions.
ACID ATTACK
Caused by an incomplete flushing after an acid cleaning process of boilers or similar equipment.
ACID CLEANING
The process of cleaning the interior surfaces of steam generating units by filling the unit with dilute acid accompanied by an inhibitor to prevent corrosion and by
ACID RAIN
Atmospheric precipitation with an pH below 5.6 to 5.7.
ACID SOAK
A method of acid cleaning, in which the acid is pumped into the boiler and rests there for a period of time.
ACIDIC
The reaction of a substance with water resulting in an increase in concentration of hydrogen ions in solution (see acid).
ACIDIFIED
The addition of an acid (usually nitric or sulfuric) to a sample to lower the pH below 2.0. The purpose of the acidification is to “fix” a sample so it will not change until it is
ACIDITY
Represents the amount of free carbon dioxide, mineral acids, and salts (especially sulfates of iron and aluminum) which hydrolyze to give hydrogen ions in the water. The
ACOUSTIC
A term pertaining to sound, or the science of sound.
ACTIVATED CARBON
Is a specially processed carbon, used as a filter drier. Commonly used to clean air.
ACTIVATED SLUDGE
An aerobic biological process for conversion of soluble organic matter to solid biomass, removable by gravity or filtration.
ACTIVE STORAGE PILE
A method of stockpiling coal, sometimes called live storage. The pile is located outside the plant but adjacent to it, and usually contains four or five days of
ACTUATOR
The portion of a regulating valve, which converts mechanical, fluid, thermal, or electrical energy
ADIABATIC
Occurring with no addition or loss of heat from the system under consideration.
ADIABATIC CHANGE
A change in the volume, pressure, or temperature of a gas, occurring without a gain of heat or loss of heat.
ADIABATIC COMPRESSION
Compressing a gas without removing or adding heat.
ADIABATIC COOLING
A method in which paramagnetic salts are pre
ADIABATIC EFFICIENCY
The ratio of actual work output of a heat engine to the ideal output.
ADIABATIC EXPANSION
The expansion of a gas, vapor, or liquid stream from a higher pressure to a lower pressure, with no change in enthalpy.
ADJUSTABLE RESISTOR
A resistor whose value can be mechanically changed, usually by the use of a sliding contact.
ADSORBENT
A material which has the ability to cause molecules of gases, liquids or solids to adhere to its internal surfaces without changing the adsorbent physically or chemically.Adsorption is the adhesion of atoms, ions or molecules from a gas, liquid or dissolved solid to a surface. This process creates a film of the adsorbate on the surface of the adsorbent. This process differs from absorption, in which a fluid is dissolved by or permeates a liquid or solid.
ADSORPTION
A material which has the ability to cause molecules of gases, liquids or solids to adhere to its internal surfaces without changing the adsorbent physically or chemically.Adsorption is the adhesion of atoms, ions or molecules from a gas, liquid or dissolved solid to a surface. This process creates a film of the adsorbate on the surface of the adsorbent. This process differs from absorption, in which a fluid is dissolved by or permeates a liquid or solid.
ADVECTION
The transfer of heat by horizontal movement of air.
AERATION
Exposing to the action of air, like blowing air through water before discharging to a river.
AEROBIC
A condition in which “free” or dissolved oxygen is present in water.
AERODYNAMIC NOISE
Also called generated noise, self
generated noise
is noise of aerodynamic origin in a moving fluid arising from flow instabilities. In duct systems, aerodynamic
AGGLOMERATE
The clustering together of a few or many particles into a larger solid mass.
AGITATOR
A device used to cause motion in confined fluids.
AIR
A substance containing by volume approximately 79% nitrogen 20.95% oxygen, .94% argon, traces of carbon dioxide, helium, etc.
AIR CHANGES
A method of expressing the amount of air leakage into or out of a building or room in terms of the number of building volumes or room volumes exchanged.
AIR COIL
Coil on some types of heat pumps used either as an evaporator or a condenser.
AIR CONDITIONER
They are basically refrigeration devices cooling air and rooms rather then food compartments.
AIR CONDITIONER, UNITARY
An evaporator, compressor, and condenser combination
AIR CONDITIONING
The process of treating air to simultaneously control its temperature, humidity, cleanliness, and distribution to meet the requirements of the conditioned space.
AIR CONDITIONING UNIT
An assembly of equipment for the treatment of air so as to control, simultaneously, its temperature, humidity, cleanliness and distribution to meet the
AIR CONDITIONING, COMFORT
The process of treating air so as to control simultaneously its temperature, humidity, cleanliness and distribution to meet the comfort requirements
AIR COOLER
A factory
AIR DIFFUSER
A circular, square, or rectangular air distribution outlet, generally located in the ceiling and comprised of deflecting members discharging supply air in various directions
AIR DIFFUSION AERATORS
They are aerators into which air is pumped into the water through perforated pipes, plates, or any other method.
AIR DUCT
A tube or conduit for conveying air from one place to another.
AIR FLOTATION
A process of accelerating sedimentation, by introducing air into the water, this lowers the density of the water, and increases the differences in the densities of the
AIR GAP
The space between magnetic poles, or between the rotating and stationary assemblies in a motor or generator.
AIR HANDLER
The fan blower, heat transfer coil, filter, and housing parts, of a system.
AIR PURGE
The removal of undesired matter by replacement with air.
AIR SATURATED
Moist air in which the partial pressure of the water vapor is equal to the vapor pressure of water at the existing temperature. This occurs when dry air and saturated
AIR VENT
Valve, either manual or automatic, to remove air from the highest point of a coil or piping assembly.
AIR, AMBIENT
Generally the air surrounding the object.
AIR, DRY
Air without contained water vapor.
AIR, OUTDOOR
Air taken from outdoors and, therefore, not previously circulated through the system.
AIR, RECIRCULATED
Return air passed through the conditioner before being again supplied to the conditioned space.
AIR, REHEATING
In an air conditioning system, the final step in treatment, in the event the temperature is too low.
AIR, RETURN
Air returned from conditioned or refrigerated space.
AIRBORNE SOUND
Sound which reaches the point of interest by radiation through the air.
AIR
COOLED CONDENSER
ALCOHOL BRINE
A water and alcohol solution, which remains as a liquid below 0°C.
ALGAE
A minute fresh water plant growth which forms a scum on the surfaces of recirculated water apparatus, interfering with fluid flow and heat transfer. Lower form of plant life,
ALKALI
A substance having marked basic properties. Applying to hydroxides of potassium, sodium, lithium, and ammonium. They turn red litmus to blue. Includes hydroxides of the
ALKALINE
Having a pH greater than 7.
ALKALINITY
An expression of the total basic anions (hydroxyl groups) present in a solution. It also represents, particularly in water analysis, the bi
ALLEN TYPE SCREW
A screw with a recessed hex shaped head.
ALLOY
A substance having metal properties and being composed of two or more chemical elements of which at least one is a metal.
ALLOY STEEL
Steel containing specific quantities of alloying elements (other than carbon)and commonly accepted amounts of manganese, copper, silicon, sulfur, and phosphorus).
ALTERNATING CURRENT (AC)
Electric current in which the direction of the current alternates or reverses. In a 60 Hertz (cycle) current, the direction of current flow reverses in
ALTERNATOR
A device which converts mechanical energy, into alternating current.
ALTIMETER
An instrument used to measure the height above a reference point, such as ground or sea level.
ALUM
Is an aluminum sulfate or filter alum. Acts in the range of 5.0 to 8.0 pH.
ALUMINA
Aluminum oxide occasionally found as an impurity in water in very small amounts.
AMBIENT AIR TEMPERATURE
Temperature of fluid (usually air) which surrounds object on all sides.
AMBIENT CONDITIONS
The conditions of temperature, pressure, and humidity, existing around an instrument.
AMBIENT NOISE
The normal sound in a room or other location.
AMINE
A chemical use in water treatment as a filming or neutralizing agent to protect the metal parts.
AMMETER
An instrument for measuring the magnitude of electric current flow.
AMMETER SHUNT
A low
AMMONIA
Chemical combination of nitrogen and hydrogen (NH3). Ammonia is a very efficient refrigerant and identified as R
AMORPHOUS
A solid not having a repetitive three
AMPACITY
A wire’s ability to carry current safely, without undue heating. The term formerly used to describe this characteristic was current capacity of the wire.
AMPERAGE
An electron or current flow of one coulomb per second, past a given point in a circuit.
AMPERE
The unit used for measuring the quantity of an electrical current flow. One ampere represent a flow of one coulomb per second.
AMPERE HOUR
A term used for rating battery capacity. As stated, an ampere for an hour
AMPERE TURNS
A term used to measure magnetic force. It represents the product of amperes, times the number of turns of the coil, in an electromagnet.
AMPLIFICATION
The process of obtaining an output signal greater than the input signal, through auxiliary power controlled by the input signal. The process of increasing the
AMPLITUDE
The maximum instantaneous value of alternating current or voltage. It can be in either a positive or negative direction. The greatest distance through which an oscillating
ANAEROBIC
A condition in which “free” or dissolved oxygen is not present in the water.
ANEMOMETER
An instrument for measuring the velocity of a fluid.
ANGLE VALVE
A type of globe valve design, having pipe openings at right angles to each other. Usually one opening on the horizontal plane and one on the vertical plane.
ANNEAL
To soften by heating and allowing to cool slowly.
ANNEALING
A process of heat treating metal, to get the desired properties of softness and ductility, (easy to form).
ANODE
In electrolysis or electrochemical corrosion, a site where metal goes into solution as a cation leaving behind an equivalent of electrons to be transferred to the opposite
ANODIZING
The treatment of a metal surface whereby the metal is made anodic.
ANSI
American National Standard Institute, which is an organization defining standards for computer language.
ANTI KNOCK VALUE
A premature explosive combustion, as the detonation of the fuel air mixture in an internal combustion engine, produces a characteristic knock. The Anti Knock
ANTICIPATING CONTROL
One which, by artificial means, is activated sooner than it would be without such means, to produce a smaller differential of the controlled property. Heat
ANTICIPATORS
A small heater element in two
ANTIFOAM AGENTS
The reduction of carry over by the addition of polymerized esters, alcohol’s, and amides. The antifoam agent is absorbed on the steam generating surface
ANTIFOULANTS
Are materials which prevent fouling from depositing on heat transfer equipment. Materials that prevent deposits forming
ANTIFREEZE
Compounds of glycol’s or alcohol’s, that lower the freezing point of cooling water systems.
ANTIOXIDANT
A substance which when added in small amounts to petroleum products, will delay or inhibit undesirable changes
APPARENT (EMF)
The apparent voltage, as measured by the drop in pressure due to a current flowing through a resistance.
APPARENT WATTS
The product of volts times amperes, in an alternating current circuit.
AQUEOUS
Watery. A substance containing water.
AQUIFER
A porous, subsurface geological structure carrying or holding water.
ARC
A flash, caused by an electric current ionizing a gas or vapor.
ARC BRAZING
A brazing process in which the heat required is obtained from an electric arc.
ARC FURNACE
An electric furnace, in which heat is produced by an arc between two electrodes.
ARC WELDING
A group of welding processes which produce coalescence of metals by heating them with an arc, with or without the application of pressure, and with or without the
ARC WELDING
A process where coalescence is obtained by heating with an electric arc.
ARMATURE
the rotating part of an electric motor or generator. The moving part of a relay or vibrator.
ARMATURE AIR GAP
The air space between the stationary and rotating parts of a motor or generator, through which magnetic lines of force pass.
ARMATURE BACK AMPERE TURNS
The magnetic field produced by current flowing in the armature winding, that opposes and reduces the number of magnetic lines of force,
ARMATURE BAR
Copper bars used in place of wire windings, in large armatures, generators, or motors.
ARMATURE CIRCUIT
The path that the current takes, in flowing through the windings from one brush to another.
ARMATURE COIL
The loop or coil of copper wire, placed on the armature core, and forming part of the winding.
ARMATURE CORE
The laminated iron part of the armature, formed from thin sheets or disks of steel, on which the windings are placed.
ARMATURE CURRENT
The current flowing from the armature of a generator, to the armature of a motor. Not including the current taken by the shunt field.
ARMATURE DEMAGNETIZATION
The reduction in the effective magnetic lines of force, produced by the armature current.
ARMATURE REACTION
The effect, that the magnetic field produced by the current flowing in the armature, has on the magnetic field produced by the field coils.
ARMATURE REGULATING RESISTORS
Are resistors, designed to regulate the speed or torque of a loaded motor, by placing a resistance in the armature or power circuit.
ARMATURE RESISTANCE
The resistance of the wire used in the windings of the armature, measured between the rings or brushes, or from positive to negative terminals.
ARMATURE SLOT
The groove or slot in the armature core, into which the coils or windings are placed.
ARMATURE TESTER
Any device used for locating faults or defects in the armature winding.
ARMATURE VARNISH
Is a liquid put on the field and armature windings, to improve the insulation of the cotton covering on the wires.
ARMATURE WINDING
All of the copper wire placed on the armature, and through which the current flows.
AROMATICS
A group of hydrocarbons of which benzene is the parent. They are called “aromatics” because many of their derivatives have sweet or aromatic odorous.
ARTIFICIAL MAGNET
Is a manufactured magnet, which is distinguished from a natural occurring magnet.
ASHRAE
The American Society of Heating, Refrigeration, and Air Conditioning Engineers.
ASME
American Society of Mechanical Engineers.
ASME APPENDIX SECTION I
Explains matter which is mandatory, unless specifically referred to in the rules of the code, including formulas.
ASME BOILER CODE
The boiler code listing standards, specified by the American Society of Mechanical Engineers, for the construction of boilers.
ASME PART PEB SECTION I
Requirements for electric boilers.
ASME PART PFH SECTION I
Requirements for feedwater heaters.
ASME PART PFT SECTION I
Requirements for firetube boilers.
ASME PART PG SECTION I
General requirements for all methods of construction.
ASME PART PMB SECTION I
Requirements for miniature boilers.
ASME PART PVG SECTION I
Requirements for organic fluid vaporizer generators.
ASME PART PW SECTION I
Requirements for boilers fabricated by welding.
ASME PART PWT SECTION I
Requirements for watertube boilers.
ASME SECTION I
Power Boilers.
ASME SECTION II
Material specifications.
ASME SECTION III
Nuclear Power Plant Components.
ASME SECTION IV
Heating boilers.ASME SECTION IX ASME SECTION V
ASME SECTION VI
Recommended rules for the care and operation of heating boilers.
ASME SECTION VII
Recommended rules for the care and operation of power boilers.
ASME SECTION VII APPENDIX
Consists of conversion factors for converting Imperial units to SI Units.
ASME SECTION VII SUBSECTION C1
Rules for routine operation of power boilers.
ASME SECTION VII SUBSECTION C2
Operating and maintaining boiler appliances.
ASME SECTION VII SUBSECTION C3
Rules for inspection.
ASME SECTION VII SUBSECTION C4
Prevention of direct causes of boiler failure.
ASME SECTION VII SUBSECTION C5
Is partial rules for the design of installations.
ASME SECTION VII SUBSECTION C6
Operation of boiler auxiliaries.
ASME SECTION VII SUBSECTION C7
Control of internal chemical conditions.
ASME SECTION VIII
Pressure vessels.
ASME SECTION XI
Rules for inservice inspection of Nuclear Power Plant components.
ASPIRATING PSYCHROMETER
A device which draws sample of air through it to measure humidity.
ASPIRATION
Production of movement in a fluid by suction created by fluid velocity.
ASTM
American Society for Testing and Materials.
ASYNCHRONOUS
Not having the same frequency. Out of step, or phase.
ASYNCHRONOUS GENERATOR
An induction generator.
ASYNCHRONOUS MOTOR
An induction motor, whose speed is not synchronous with the frequency of the supply line.
ATMOSPHERE
Is the mixture of gases and water vapor surrounding the earth.
ATMOSPHERIC PRESSURE
Pressure exerted by the weight of the atmosphere
ATOM
The smallest complete particle of an element, which can be obtained, yet which retains all physical and chemical properties of the element.
ATOMIC NUMBER
The number of protons found in the nucleus of an atom, of an element.
ATOMIC WEIGHT
The weight of an elementary atom, in relation to the weight of an atom of hydrogen. A hydrogen atom being taken as 1.00g.
ATOMIZE
Process of changing a liquid to minute particles or a fine spray.
ATTEMPERATING WATER IMPURITY
Refers to turbine deposits caused by impurities in the water used for attemperators. (Chemicals used with attemperating water should be of the
ATTEMPERATOR
An apparatus for reducing and controlling the temperature of a superheater vapor or a fluid.
ATTENUATION
The sound reduction process in which sound energy is absorbed or diminished in intensity as the result of energy conversion from sound to motion or heat.
ATTRITION
The rubbing of one particle against another in a resin bed
AUTOMATIC CONTROL
The process of using the differences, between the actual value, and desired value, of any variable, to take corrective action, without human intervention.
AUTOMATIC CONTROLLER
A device that measures the value of a measured variable, and operates to correct or limit the deviation from a selected reference. Both measuring and
AUTOMATIC DEFROST
System of removing ice and frost from evaporators automatically.
AUTOMATIC EXPANSION VALVE (AEV)
A type of metering device that senses low
AUTOMATIC EXTRACTION UNIT TURBINE
Bleeds off part of the main steam flow at one, two, or three points. Valved partitions between selected stages control the extracted steam
AUTOMATIC FROST CONTROL
Control which automatically cycles refrigerating system to remove frost formation on evaporator.
AUTOMATIC GOVERNING SYSTEM
A system which correlates steam flow, pressure, shaft speed, and shaft output, for any one turbine unit.
AUTOMATIC ICE CUBE MAKER
Refrigerating mechanism designed to automatically produce ice cubes in quantity.
AUTOMATIC RESET (INTEGRATION)
Is a type of control, in which the controller output, changes at a rate proportional to the deviation or error. The output will continue to change
AUTOTRANSFORMER
A transformer in which both primary and secondary coils, have turns in common. The step up or step down of voltage, is accomplished by taps in common
AUXILIARY CONTACTS
A set of contacts that perform a secondary function, usually in relation to the operation of a set of primary contacts.
AVAGADRO’S HYPOTHESIS
States that equal volumes of different gases, at the same temperature and pressure, will contain equal numbers of molecules.
AVAGADRO’S NUMBER (N)
The number of elementary units such as atoms, formula units, molecules, or ions, that constitute one mole of the said particle.
AVERAGING ELEMENT
A thermostat sensing element which will respond to the average duct temperature.
AXIAL FLOW COMPRESSOR
Uses rotor blades shaped like airfoils, to bite into the air, speed it up, and push it into the subsequent stationary blade passages. These passages are
AZEOTROPE
Having constant maximum and minimum boiling points.
BACK PRESSURE
Pressure in low side of refrigerating system
BACK SEATING
Fluid opening/closing such as a gauge opening or to seal the joint where the valve stem goes through the valve body.
BACK WORK RATIO
Is the fraction of the gas turbine work used to drive the compressor.
BACKGROUND NOISE
Sound other than the wanted signal. In room acoustics, the irreducible noise level measured in the absence of any building occupants.
BACKING RING
Backing in a form of a ring, generally used in welding of piping.
BACKWASH
The counter
BACTERIA
Microscopic unicellular living organisms.
BAFFLE
Plate or vane used to direct or control movement of fluid or air within confined area.
BAGHOUSE
A chamber containing bags for filtering solids out of gases.
BALLAST GAS
Are the nonflammable portion of the gas, such as carbon dioxide.
BAROMETER
Instrument for measuring atmospheric pressure. It may be calibrated in pounds per square inch, in inches of mercury in a column in millimeters or kPa.
BASE
An alkaline substance.
BASE METAL
The metal present in the largest proportion in an alloy. (Copper is the base metal in brass)
BASE METAL
The substrate metal that is coated or protected by a surface coating.
BASICITY
The ability of a substance to boost the pH after neutralizing all the acid species.
BATCH OPERATION
The utilization of ion
BAUDELOT COOLER
Heat exchanger in which water flows by gravity over the outside of the tubes or plates.
BEARING, AIR
A bearing using air as a lubricant.
BEARING, ALIGNING
A bearing with an external spherical seat surface that provides a compensation for shaft or housing deflection or misalignment.
BEARING, ANNULAR
Usually a rolling bearing of short cylindrical form supporting a shaft carrying a radial load.
BEARING, ANTI
FRICTION
BEARING, BABBIT
A bearing metal of non
ferrous material, containing several tin
based alloys, mainly copper, antimony, tin and lead.
BEARING, BALL
A rolling element bearing in which the rolling elements are spherical.
BEARING, BIG END
A bearing at the larger (crankshaft) end of a connecting rod in an engine.
BEARING, BIMETAL
A bearing consisting of two layers.
BEARING, BOTTOM END
(see bearing, big end)
BEARING, BUSH
A plain bearing in which the lining is closely fitted into the housing in the form of a bush, usually surfaced with a bearing alloy.
BEARING, CIRCULAR STEP
A flat circular hydrostatic bearing with a central circular recess.
BEARING, FIXED PAD
An axial or radial load bearing equipped with fixed pads, the surface of which a are contoured to promote hydrodynamic lubrication.
BEARING, FLOATING
A bearing designed or mounted to permit axial displacement between shaft and housing.
BEARING, FLOATING RING
A type of journal bearing that includes a thin ring between the journal and the bearing. The ring floats and rotates at a fraction of the journal rotational
BEARING, FLUID
(see hydrostatic bearing)
BEARING, FULL JOURNAL
A journal bearing that surrounds the journal by a full 360°.
BEARING, GAS
A journal or thrust bearing lubricated with gas.
BEARING, HALF JOURNAL
A bearing extending 180° around a journal.
BEARING, JOURNAL
A machine part in which a rotating shaft revolves or slides.
BEARING, MAGNETIC
A type of bearing in which the force that separates the relatively moving surfaces is produced be a magnetic field.
BEARING, MAIN
A bearing supporting the main power
BEARING, MITCHELL
(see tilting pad bearing).
BEARING, NEEDLE
A bearing in which the relatively moving parts are separated by long thin rollers that have a length
BEARING, NONCONTACT
A bearing in which no solid contact occurs between relatively moving surfaces.
BEARING, PEDESTAL
A bearing that is supported on a column or pedestal rather than on the main body of the machine.
BEARING, POROUS
Made from porous material, such as compressed metal powders, the pores acting either as reservoirs for holding or passages for supplied lubricant.
BEARING, ROLLER
A bearing in which the relatively moving parts are separated by rollers.
BEARING, RUBBING
A bearing in which the relatively moving parts slide without deliberate lubrication.
A roller
element bearing with one spherical raceway that automatically provides compensation for shaft or housing deflection or misalignment.
A bearing independent of external lubrication. These bearings may be sealed for life after packing with grease or may contain self
lubricating material.
BEARING, SLEEVE
A cylindrical plain bearing used to provide radial location for a shat, which moves axially. Sleeve bearings consist of one or more layers of bearing alloys, bonded to
BEARING, SLIDE
A bearing used or positioning a slide or for axial alignment of a long rotating shaft.
BEARING, STEP
A plane surface bearing that supports the lower end of a vertical shaft.
BEARING, THRUST
A bearing in which the load acts in the direction of the axis of rotation.
BEARING, TILTING PAD
A pad bearing in which the pads are free to take up a position at an angle to the opposing surface according to the hydrodynamic pressure distribution over
BEARING, TRUNNION
A bearing used as a pivot to swivel or turn an assembly.
BELLOWS
Corrugated cylindrical container which moves as pressures change, or provides a seal during movement of parts.
BELLOWS SEAL
A type of mechanical seal that utilizes a bellows for providing secondary sealing.
BIMETAL STRIP
Temperature regulating or indicating device which works on principle that two dissimilar metals with unequal expansion rates, welded together, will bend as
BIMETALLIC COUPLE
A joint or union of two dissimilar metals.
BIOCIDE
A chemical used to control the population of troublesome microbes.
BLACK LIQUOR
The liquid material remaining from pulpwood cooking in the soda or sulfate papermaking process.
BLAST FURNACE GAS
Is the waste product from furnaces used to smelt iron ores.
BLEEDER VALVE
A valve designed to slowly relief a liquid or gas form system.
BLEEDING
Slowly reducing the pressure of liquid or gas from a system or cylinder by slightly opening a valve.
BLEEDOFF
The continuous removal of water from a re
BLEEDOFF RATE
The rate at which water is continuously removed from a system.
BLOWDOWN
In connection with boilers or cooling towers, the process of discharging a significant portion of the aqueous solution in order to remove accumulated salts, deposits and
BOILER
Closed container in which a liquid may be heated and vaporized.
BOILER FEED WATER
The total water fed to a boiler producing steam. This water is the mixture of return steam condensate and makeup water.
BOILER HORSEPOWER
The work required to evaporate 34.5 lb of water per hour into steam from and at 100°C.
BOILER LAY
UP
BOILING
(See vaporization)
BOILING OUT
The boiling of high alkaline water in boiler pressure parts for the removal of oil, greases, prior to normal operation or after major repairs.
BOILING POINT
The temperature at which the vapor pressure of a liquid equals the absolute external pressure at the liquid
BOILING TEMPERATURE
Temperature at which a fluid changes from a liquid to a gas.
BORE
Inside diameter of a cylinder.
BOURDON TUBE
Thin
BOYLES’ LAW
If the temperature on a gas is constant, the volume is inversely proportional to the pressure. By formula
BRANCH CIRCUIT
Wiring between the last overcurrent device and the branch circuit outlets.
BRASS
A copper
BRAYTON CYCLE (also referred to as the Joule Cycle)
A rotating machine in which compression and expansion take place. Gas turbine are such an example.
BRAZE
A weld produced by heating an assembly to suitable temperatures and by using a filler metal having a liquidus above 450°C. The filler metal is distributed between the closely
BRAZING, BLOCK
A brazing process in which the heat required is obtained from heated blocks applied to the parts to be joined.
BREAKTHROUGH
The first appearance in the solution flowing from an ion
BRINE
Water saturated with a chemical such as salt.
BRITISH THERMAL UNIT, (BTU)
The Btu is defined as the heat required to raise the temperature of a pound of water from 59° to 60°F.
BRITTLENESS
The tendency of a material to fracture without first undergoing significant plastic deformation.
BRONZE
A copper
BTU
British Thermal Unit.
BYPASS
A pipe or duct, usually controlled by valve or damper, for conveying a fluid around an element of a system.
BYPASS
Passage at one side of, or around, a regular passage.
BYPASS FEEDER
A closed tank that is installed in a system in “bypass,” that is, in a side stream taken off the system and leading back to the system rather than directly in
BY
PASS GOVERNING
CALCAREOUS COATING OR DEPOSIT
A layer consisting of a mixture of calcium carbonate and magnesium hydroxide deposited on surfaces being cathodically protected against
CALCIUM
A scale forming element found in boiler feedwater.
CALCIUM CHLORIDE
A substance used to obtain calcium chloride brine.
CALCIUM SULFATE
Chemical compound (CaSO4) which is used at a drying agent or desiccant in liquid line dryers.
CALIBRATION
A process of dividing and numbering the scale of an instrument
CALORIE
It is equal to the amount of heat required to raise the temperature of one gram of water one degree Celsius.
CALORIMETER
Device used to measure quantities of heat or determine specific heats.
CANGE OF STATE
Change from one phase, such as solid, liquid or gas, to another.
CAPACITANCE
The property of an electric current that permits the storage of electrical energy in an electrostatic field and the release of that energy at a later time.
CAPACITOR, (CONDENSER)
A device that can store an electric charge when voltage is applied.
CAPACITY
The adsorption activity possessed in varying degrees by ion
exchange materials. This quality may be expressed as kilograins per cubic foot, gram
milliequivalents per gram,
pound
equivalents per pound, gram
CAPILLARY
The name given to the thin tube attached to the bulb which transmits the bulb pressure changes to the controller or indicator. The cross sectional area of the capillary is
CAPILLARY TUBE
The capillary tube is a metering device made from a thin tube approximately 0.5 to 6 metre long and from 0.025 to 0.090 inches in diameter which feeds liquid directly
CARBON DIOXIDE
Compound of carbon and oxygen (CO2) which is sometimes used as a refrigerant. Refrigerant number is R
CARBON FILTER
Air filter using activated carbon as air cleansing agent.
CARBON TETRACHLORIDE
Colorless nonflammable and very toxic liquid used as a solvent. It should never be allowed to touch skin and fumes must not be inhaled.
CARBONACEOUS EXCHANGER
Ion
CARBONATE
An ion or salt of carbonic acid, containing carbon and oxygen such as calcium carbonate. (CaC03)
CARBONATE HARDNESS
That hardness caused in water by bicarbonates and carbonates of calcium, and magnesium.
CARBONATE
POLYMER TREATMENT
A treatment method using synthetic polymers, generally used with high hardness (60
70) ppm and high alkalinity.
CARBOXYLIC
A term describing a specific acidic group (COOH) that contributes cation
CARRYOVER
The moisture and entrained solids forming the film of steam bubbles, as a result of foaming in a boiler. This condition is caused by a faulty boiler water condition. See
CASCADE
A series of stages in which the output of one stage is the input of the next stage.
CASCADE SYSTEMS
Arrangement in which two or more refrigerating systems are used in series
ultra
low temperatures.
CATHODE
In electrolysis or electrochemical corrosion, a site on a surface where actions in solution are neutralized by electrons to become elements that either plate out on the surface
CATHODIC PROTECTION
A method of preventing corrosion by making the metal a cathode in a conducting medium by means of a direct electrical current that is galvanic.
CATHODIC PROTECTION
Reduction of corrosion rate by shifting the corrosion potential of the electrode towards less oxidizing potential by applying an external electromotive force.
CATION
A positively charged ion that migrates through the electrolyte toward the cathode under the influence of a potential gradient.
CATION
EXCHANGE SOFTENERS
CATIONIC
The condition of a polymer, colloid, or large particle having exchangeable anions on its surface and an opposite, positive charge on the substrata.
CAUSTIC CRACKING
A form of stress
corrosion cracking most frequently encountered in carbon steels or iron
chromium
CAUSTIC EMBRITTLEMENT
An obsolete term replaced by caustic cracking.
CAUSTIC SODA
A common water treatment chemical, sodium hydroxide.
CAVITATION
The formation and collapse, within a liquid, of cavities or bubbles that contain vapor or gas or both. In general, cavitation originates from decreases in static pressure in
CAVITATION EROSION
Progressive loss of original material from a solid surface due to continuing exposure to cavitation.
CELSIUS TEMPERATURE SCALE
A thermometric scale in which the freezing point of water is called 0°C and its boiling point 100°C at normal atmospheric pressure.
CENTANE NUMBER
A measure of ignition quality of a fuel or petroleum with reference to normal centane high
CENTRIFUGAL COMPRESSOR
Pump which compresses gaseous fluids by centrifugal force.
CENTRIFUGAL FORCE
On a centrifugal pump, it is that force which throws water from a spinning impeller.
CENTRIFUGAL PUMP
A pump consisting of an impeller fixed on a rotating shaft and enclosed in a casing, having an inlet and a discharge connection. The rotating impeller creates
CENTRIFUGAL PUMP
Pump which produces fluid velocity and converts it to pressure head.
CHANGE OF STATE
Condition in which a substance changes from a solid to a liquid or a liquid to a gas caused by the addition of heat. Or the reverse, in which a substance changes
CHANNELING
Cleavage and furrowing of the bed due to faulty operational procedure, in which the solution being treated follows the path of least resistance, runs through these
CHARGE
Amount of refrigerant placed in a refrigerating unit.
CHARGING BOARD
Specially designed panel or cabinet fitted with gauges, valves and refrigerant cylinders used for charging refrigerant and oil into refrigerating mechanisms.
CHECK VALVE
Device which permits fluid flow in one direction.
CHELATE
Is a molecule, similar to an ion exchanger, capable to withdraw ions from their water solutions into soluble complexes.
CHEMICAL CLEANING
Using a solvent solution to remove mill scale and corrosion products.
CHEMICAL FEEDLINE
The line which feeds the boiler treatment chemicals into the boiler.
CHEMICAL PRECIPITATION
When the chemicals react with the dissolved minerals in the water to produce a relative insoluble reaction product. A typical example of this takes place
with the lime
soda softening process.
CHEMICAL REFRIGERATION
System of cooling using a disposable refrigerant. Also called an expendable refrigerant system.
CHEMICAL STABILITY
Resistance to chemical change which ion
CHILL FACTOR
Calculated number based on temperature and wind velocity.
CHILLED
WATER SYSTEM
A re
circulating water system using water chilled in a refrigeration machine as a source for cooling.
CHILLER/HEATERS
A unit that supplies either chilled water for cooling or hot water for heating, (HVAC).
CHLORIDE
An ion, compound, or salt of chlorine, such as sodium chloride (NaCl) or calcium chloride (CaCl2).
CHLORINATION
A process in which chlorine gas or other chlorine compounds are added to the water for the purpose of disinfecting.
CHOKE TUBE
Throttling device used to maintain correct pressure difference between high
side and low
side in refrigerating mechanism. Capillary tubes are sometimes called choke
CHORDAL THERMOCOUPLE
A thermocouple installed in furnace tubes, designed to measure the effectiveness of water treatment within the boiler.
CIRCUIT
An electrical arrangement requiring a source of voltage, a closed loop of wiring, an electric load and some means for opening and closing it.
CIRCUIT BREAKER
A switch
CLAY
Finely suspended earth mineral sometimes found as an impurity in water.
CLEARANCE SPACE
Space between top of piston and the valve plate.
CLEARANCE VAPOR
The vapor remaining in the clearance space at the end of each discharge stroke.
CLOSED CYCLE
is the gas turbine arrangement, in which the exhaust is directed back again to compressor without coming in contact with the atmospheric air.
CLOSED FEEDWATER HEATER
An indirect
CLOSED RE
CIRCULATING WATER SYSTEM
A system using as a heat
transfer medium water that continuously circulates through closed piping and heat exchanger without
COCOAGULANT
A substance that promotes the clumping of particulate matter in water, forming a larger mass and thus promoting settling of particulates and clarification of the water.
COAGULATION
Is the process whereby finely divided particles of turbidity and color, capable of remaining in suspension indefinitely, are combined by chemical means into masses
COALESCENCE
The gathering together of coagulated colloidal liquids into a single continuous phase.
CODE INSTALLATION
Refrigeration or air conditioning installation which conforms to the local code and/or the national code for safe and efficient installations.
CO
EFFICIENT OF CONDUCTIVITY
COEFFICIENT OF EXPANSION
A measure of the change in length or volume of an oject, specifically, a change measured by the increase in length or volume of an object per unit
COEFFICIENT OF FRICTION
The dimensionless ratio of the friction force (F) between two bodies to the normal force (N) pressing these bodies together
COEFFICIENT OF PERFORMANCE (COP)
Ratio of work performed or accomplished as compared to the energy used under designated operating conditions.
COGENERATION
A term used to describe the combination of different thermodynamic cycles for the purpose of increasing all
CO
GENERATION GENERATION
a term applied to identify the generation of people interested in co
generation.
COLD
The absence of heat
COLD DECK
The cooling section of a mixed air zoning system.
COLD JUNCTION
That part of a thermoelectric system which absorbs heat as the system operates.
COLD PROCESS
A water treatment process carried out at room temperature.
COLD WALL
Refrigerator construction which has the inner lining of refrigerator serving as the cooling surface.
COLLOIDAL
A state of suspension in a liquid medium in which extremely small particles are suspended and dispersed but not dissolved.
COLLOIDS
Organic matter of very fine particle size, usually in the range of 10
5 to 10
7 cm in diameter. It tends to inhibit the formation of dense scale and results in the deposition of
COLUMN OPERATION
Conventional utilization of ion
COMBINED FEEDER CUTOFF
A device that regulates makeup water to a boiler in combination with a low
COMBINED STEAM
GAS PLANT
COMBINED TREATMENT
A method of physical treatment , followed by the addition of chemicals to remove oxygen.
COMBUSTION
The act or process of burning.
COMFORT CHART
A chart showing effective temperatures with dry
COMFORT COOLER
System used to reduce the temperature in the living space in homes. These systems are not complete air conditioners as they do not provide complete control of
COMFORT COOLING
Refrigeration for comfort as opposed to refrigeration for storage or manufacture.
COMFORT ZONE
(Average) the range of effective temperatures over which the majority (50 percent or more) of adults feels comfortable
COMMON NEUTRAL
A neutral conductor that is common to, or serves, more than one circuit.
COMPOSITION
The elements or chemical components that make up a material and their relative proportions.
COMPOUND
They are chemically combined elements with definite proportions of the component elements.
COMPOUND GAUGE
Instrument for measuring pressures both above and below atmospheric pressure.
COMPOUND REFRIGERATING SYSTEMS
System which has several compressors or compressor cylinders in series. The system is used to pump low pressure vapors to condensing
COMPRESSION
Term used to denote increase of pressure on a fluid by using mechanical energy.
COMPRESSION RATIO
Ratio of the volume of the clearance space to the total volume of the cylinder. In refrigeration it is also used as the ratio of the absolute low
the absolute high
side pressure.
COMPRESSION, ADIABATIC
Is compressing a gas without removing or adding heat.
COMPRESSOR
Pump of a refrigerating mechanism which draws a low pressure on cooling side of refrigerant cycle and squeezes or compresses the gas into the high
COMPRESSOR
The pump which provides the pressure differential to cause fluid to flow and in the pumping process increases pressure of the refrigerant to the high side condition.
COMPRESSOR DISPLACEMENT
Volume, in cubic inches, represented by the area of the compressor piston head or heads multiplied by the length of the stroke.
COMPRESSOR SEAL
Leak proof seal between crankshaft and compressor body in open type compressors.
COMPRESSOR SURGING
An instability of air flow with axial compressor on the first stages of these compressors. Air flow might even be reversed that point.
COMPRESSOR TURBINE
in terms of a gas turbine arrangement, it is the turbine which drives the compressor only.
COMPRESSOR, CLEARANCE POCKET
Small space in a cylinder from which compressed gas is not completely expelled. This space is called the compressor clearance space or
COMPRESSOR, ROTARY BLADE
Mechanism for pumping fluid by revolving blades inside cylindrical housing.
COMPRESSOR, SINGLE
STAGE
Compressor having only one compressive step between low
side pressure and high
COMRESSIBILITY
The ease which a fluid may be reduced in volume by the application of pressure, depends upon the state of the fluid as well as the type of fluid itself.
