Document 99ZzkJLoxQn0k9O6r2kwJXddD

952 CHAPTER 67 1965 Guide And Data Book Air, return: air returned from conditioned or refrigerated space, point or a flash point above 150 F'as determined by American air, saturated: moist air in which the partis] pressure of the Society for Testing Materials Method D93. water vapor b equal to the vapor pressure of water at the exiatingyrc brine, electrolytic: any brine capable of causing rhomi^l de temperature. Hus occurs when dry air and saturated water vdpcSr" 1 ' composition of one of two rfiwwmilar metals by electrolysis, coexist at the same dry-bulb temperature. brine cooler: evaporator for cooling brine in an indirect system, air, standard: air with a density of 0.075 lb per cu-ft and an-*-., brine expansion tank: a vented reservoir in a closed circulating absolute viscosity of 0.0379X10-* lb per (ft) (sec).'Thb i/ 1 brine system for the accommodation of volume expansion of brine substantially equivalent to dry air at 70 F and 29.92 ini Kg4---^ due to temperature change. barometric pressure. brine return tank: a reservoir in an open circulating brine sys air, supply: the quantity of air delivered to each or any space ^ ... tem for the storage of brine at the pump suction and for inspec in the system, or the total delivered to all spates in the system!" tion of the condition and flow of brine. air ventilation: the quantity of supply air required to maintain brine tank: in an ice plant, the main freezing tank in which the the desired quality of air within a designated space. - --------- cans are immersed while ice is being produced. In a brine drcu-- air tunnel: a refrigerated tunnel with rapid air circulation lating system, a storage tank or haJanf* tank for brine. In domes through which the product to be frozen is passed. . air washer: a water spray system or device for cleaning; humidifying, or dehumidifying the air. algae: a minute fresh water plant growth which forms a,scum oo the surfaces of recirculated water apparatus, interfering with fluid flow and heat transfer. , :; analyzer: device in high side of absorption system for increas ing the concentration of refrigerant in the vapor entering-rectifier or condenser.' ... anemometer: an instrument for measuring the velocity-of a fluid. approach: in an evaporative cooling device, the difference'be^- tween the average temperature of the circulating water leaving the device, and the average wet-buib temperature of the entering tic and commercial fields, a container surrounding the evaporator and filled with brine for storing refrigeration or for equalizing'tern; perature at various points of the evaporator, especially In ice cream cabinets. British thermal unit (Bta): the Btu is defined as 778.177 foot pounds if it is related to the IT calorie in such a way that 1 IT calorie'per (kg) (C deg) -- 1 Btu per (lb) (F deg); with''lib" * 453.5924g. Approximately, it is the heat required to raise the' temperature of a pound of water from 59 F to 60 F. banker: space in refrigerator given to ice or cooling element? bypass: a pipe or duct, usually controlled by valve or damper, for conveying a fluid around an element of a system! - calibration: process of dividing and numbering the scale of an. instrument: also of correcting or determining the error of-an existing scale, or of evaluating one quantity in terms of readings of another. aspect ratio: in air distribution outlets, the ratio of the-lengtb of the core opening of a grille, face, or register to the width.* * In rectangular ducts, the ratio of the width to the depth! calorie: heat required to raise the temperature of 1 gram of: water 1 C, actually from 4 C to 5 C. Mean calorie 1/I00 part of the heat required to raise 1 gram of water from 0 to. 100 C. ? aspiration: production of movement in a fluid by suction created by fluid velocity. ....... atomize: reduce to fine spray. attenuation: the sound reduction process in which sound energy is absorbed or diminished in intensity as'the result of energy con version from sound to motion or heat. baffle: a surface used for deflecting-fiuids, usually in the form' of a plate or walL barometer: instrument used for-measuring atmospheric pres-; sure. - i - ... Uut heater: a set of heat transfer coils or sections used to heat' air which is drawn or forced through it by a fan. . ': blow (throw): in 'air distribution, the distance an air stream' travels from an outlet to a position at which air motion along the axis reduces to a velocity of. 50 fpm. For unit heaters, the Hiataraa an air stream travels from a heater without a perceptible rise due to temperature difference, and toss of velocity. boiler: a closed vessel in which a liquid is heated or vaporized, boiler heating surface: aQ of the surface of the heat-transfer' apparatus in contact on one side with the .water or wet steam being heated and on the other side mth the gas or refractory be-, ing cooled, in which the fluid being heated forma.part of the circulating system, this surface, to be measured on the side re ceiving heat. (Stationary Steam-Generating Units, ASMS Power TcstCodes, PTC 4-1946.) . calorimeter: device for measuring beat quantities, such .as machine capacity, beat of combustion, specific heat, vital heat,beat leakage, etc. Also device for measuring quality (or moisture content) of steam or other vapor. capacitor: a device, the primary purpose of which is to introduce capacitance into an electric circuit. capacity: the usable output of a system or system component in which only losses occurring in the system or component are charged against it. ... capacity, heat: the amount of heat necessary to raise the tern-, perature of a given mass one degree. Numerically, the mass multi plied by the specific heat. capacity reducer: in a compressor, a device such as.a clearance pocket, movable cylinder head, or suction bypass, by which com-, pressor capacity can be adjusted without otherwise changing the operating conditions. capillarity: the action by which the surface of a liquid where it is in contact with a solid (as in a slender tube) is raised or lowered. capillary tube: in refrigeration practice a tube of gmAli internal diameter used as a liquid refrigerant flow control or expansion, device between high and low sides; also used to transmit pressure from the sensitive .bulb ,of some temperature controls to.the operating element. Centigrade: a thermometric scale in which the freezing point of water is called 0 deg and its boiling point 100 deg-at normal atmospheric pressure (14.696 pei). Direct Beating Surface is generally understood to be'theboder, Keating surface subject to direct radiation from'the surface of the grate, or from the surfaces of oil or gas burners."-'- change of air: introduction of new, cleansed or recirculated air to conditioned space, measured by the number of complete' changes per unit time. Indirect Beating Surface is' the boiler heating surface within the flues. .' change of state: change from one phase, such as solid, liquid, or gas, to another. , boiler horsepower: the equivalent evaporation of 34^5 Ib'-of water per hr from and at 212 F. This is equal to a heat output'of, 970.3 X 34.5 - 33,475 Btuh. , , " ; boiling point: the temperature at which the vapor pressure,of a liquid equals the absolute external pressure at the liquid-vapor interface. bore: inside diameter of a cylinder, i, brazed: joined by fusion using-a spelter on the order of brass. This is considered equivalent to bard soldering. ... . . breaker strip: a relatively poor conductor of heat used to join the liner and outer shell of an internally refrigerated container such as'a refrigerator. brine: any liquid cooled by the refrigerant and-used for .the transmission of heat without a charge in its state, having no flah charge: amount of refrigerant in a system; to put in the re frigerant charge. fhttl: to apply refrigeration moderately, as to meats, without- freezing. i chilled cargo: cargo maintained at an assigned temperature above its freezing point. ' rhitling room: room where products are cooled prior to cold storage. chimney effect: the tendency of air or gas in a duct or other vertical passage to rise when heated due to its lower density compared with that of the'surrounding air or gas. In'buildings, the tendency toward displacement caused (by the difference in temperature) of internal heated air by unheated outside air due to the difference in density of outside and inside air. Terminology clearance: space m cylinder not occupied by piston at end of compression stroke, or volume of gas remaining in cylinder at point; measured in percentage of piston displacement..; coefficient of discharge: for an air diffuser, the ratio of net area or effective area at vena contracts of an orifieed air stream tothe free area of the opening. coefficient of expansion: the change in length per unit length or the change in volume per unit volume, per deg change in tempera ture. coefficient of performance (heat pomp): ratio of heating effect produced to the energy supplied---beating effect 'and energy supplied expressed in the same thermal units.' t of performance (refrigerating uni): .ratio of the refrigeration produced to the work supplied--refrigeration and work each expressed in the same thermal units. cofl: a f*v>lng or heating element made of pipe or tubing: -'. direct expansion: coQ using the direct method of refrigerar- tion. !-v cold storage: a trade or process of preserving perishables on a Urge scale by refrigeration. ' comfort chart: a chart showing effective temperatures with drybulb temperatures and humidities (and sometimes air motion) by which the effects of various air conditions on human comfort may be compared. comfort line: a line on the comfort chart showing relationbetween the effective temperature and the percentage of adults feed ing comfortable. compression: in a compression refrigeration system, a process by which the pressure of the refrigerant is increased.. compression, compound: see compression, multistage. , compression multistage: compression in two or more- steps, as where the discharge of one compressor is connected with -the suction of another. . compression, ratio of: ratio of absolute pressures after and be fore compression. .- -: compression, wet: a system of refrigeration in which some Bquid refrigerant is mixed with vapor entering the compressor so as to cause the discharge vapors from the compressor to be saturated rather than superheated. y, compressor, booster: a compressor for very low pressures, usually discharging into the suction line of another compressor! compressor, centrifugal: a nonpositive displacement compres sor which depends for pressure rise, at least-in part, oo cen trifugal effect. compressor, compound: a compressor in which compression is accomplished by stages, as in two or more cylinders. compressor, mechanical refrigerant:-a specific machine; ,with or without accessories, for compressing a given refrigerant vapor. compressor, open-type: a compressor with a shaft or other mov^ ing part extending through a casing to be driven by an outside source of power, thus requiring a stuffing box, shaft seals or equivalent rubbing contact between a fixed and moving part. - 1 compressor, positive~displacement: a compressor, in .which in! crease in vapor pressure is attained by changing the internal volume of the compression chamber. , compressor, reciprocating: a positive displacement compressor with a piston or pistons moving in a straight line but alternately in opposite directions. compressor, rotary: one in which compression is,attained in a cylinder by rotation of a positive displacement member. _ compressor, sealed .refrigerant: a mechanical compressor combination consisting of a compressor and a motor, both of which are enclosed in toe same housing, with no external shaft or shaft seals, the motor operating in the refrigerant atmosphere. - concentration: a number in percentage specifying the composi tion of a solution with respect to the constituent as lb of salt per gal of brine. condensate: the liquid formed by condensation of a vapor..In steam heating, water condensed from steam; in air conditioning, water extracted from air, as by condensation on the cooling bop of a refrigeration machine. , condensation: the process of changing a vapor into liquid By the extraction. of beat. Condensation of steam or water vapqr?ts effected in either steam condensers or in dehumidifying coils and the resulting water is called condensate: : 'u condenser: a vessel or arrangement of pipe or tiibing in which a vapor fa liquefied by removal <5 heat. 953 condenser, air-cooled refrigerant:. a condenser eooled<-hy natural or forced circulation of atmospheric air through it. : condenser, atmospheric - refrigerant:. condenser cocded -with water which ia exposed to the atmosphere. condenser, evaporative refrigerant: an assembly of heat trans fer elements in wnich a minor part of the heat transferred from the refrigerant vapor and liquid increases the sensible heat of an air stream forced through the heat transfer elements and the re; mwJrwHtfr evaporates water sprayed over the heat transfer ele ments. condenser, open sheQ-and-tobe: one in which the water passes in a film over the inner surfaces of the tubes, which are open to.the atmosphere. condenser, shell-and-coil refrigerant: one in which the refrig erant vapor is condensed in a closed shell, with the cooling water circulated through one or more continuous or assembled coils contained within the shell. :(` condenser, sheQ-and-tobe refrigerant: one in which the refrig erant vapor ia either bn the inside or on the outside of a group of straight parallel ,tubes within a closed shell, with the tubes terminating at each end in a'tube sheet. condenser, tube-in-tubc refrigerant: consists of one or more assemblies of two tubes, one within the other, in which the. re* frigerant vapor is condensed either in the annular space or in the inner tube. condenser, water-coded refrigerant: an assembly of elements by which the flows of refrigerant vapor and water are maintained in such a heat transfer relationship that the refrigerant vapor is condensed into a liquid and toe water is heated. condensing : a specific refrigerating machine combination for a given refrigerant, consisting of one or more power-driven compressors, condensers, liquid receivers (when required), and the regularly-furnished accessories. condensing ***, hermetically-sealed: a sealed condensing unit in which the motor-compressor housing is permanently sealed by welding or brazing, and is not provided with means of access for servicing internal parts in the field. condensing tmlt, mechanical: a complete high side of a refrig eration system including the motor in a unit assembly. condensing unit, sealed: a mechanical condensing unit, in which the compressor and compressor motor are enclosed in the same housing, with no external shaft or shaft seal, the compressor motor operating in the refrigerant atmosphere. condensing unit, service-sealed: a sealed condensing unit in which the motor-compressor housing is sealed by one or more gaskets and means of are provided for servicing internal parts in the field conductance, surface: the time rate of heat flow per unit area under steady conditions between a surface and toe ambient fluid for unit temperature difference between the surface and the fluid. conductance, thermal: the time rate of heat flow through a body per unit area from one of its bounding surfaces to the other for a unit temperature difference between the two surfaces, under steady conditions. The term is applied to specific bodies or construction3 as used, either homogeneous or heterogeneous, -`-nr) conduction, thermal: toe process of beat transfer through a material rmJhim in which-kinetic energy is transmitted by the particles of the material from particle to particle without gross displacement of the particles. -i conductivity, thermal: the time rate of heat-flow through-unit area of a homogeneous material under steady conditions when a unit temperature gradient, is maintained in toe direction .per pendicular to area. Materials are considered homogeneous when the value of the thermal,conductivity is not affected by variation in thickness or in size of sample within the range normally,used in construction. conductor, thermal: a material which readily transmits'heat1by means of conduction. , conduit: a tube or pipe used for conveying fluid. Also a tube or pipe in which wiree may be laid for protection. connecting rod: a device connecting the piston to a crank and used to change rotating motion into reciprocating motion, or vice versa, as from rotating crankshaft to reciprocating piston.,;., conservation of energy: the principle which, assumes that en ergy can be neither created oor destroyed. . , control: any device for regulation of a system or component-in normal operation, manual or automatic. If automatic, theimplica tion is that it is responsive to changes of pressure, temperature or other property whose magnitude is to be regulated. . control, anticipating: one which, by artificial means,is'activated