BS ISO 3857-4:2012 pdf download – Compressors, pneumatic tools and machines — Vocabulary — Part 4: Air treatment
1 Scope
This part of ISo 3857 identifies the terms andprovides the definitions for the vocabulary used inthe air-treatment field.
2Terms and definitions
2.1
absorption
process of attracting one substance into the massofanother，so that the absorbed substancecombines with the absorbent
2.2
activated alumina
highly porous and granular form of aluminium oxidehaving preferential adsorptive capacity for moisturefrom gases, vapours and some liquids
2.3
activated carbon
any form of carbon characterized by high adsorptivecapacity for gases and vapours
2.4
actual vapour pressure
partial pressure exerted by the vapour under theactual temperature condition of the environment
2.5
adiabatic
expansion or compression of a gas without loss orgain of heat content
2.6
adsorption
physical process in which the molecules of a gas,vapour or liquid adhere to the surface of a solid
2.7
aerosol
suspension in a gaseous medium of solid particles,liquid particles or solid and liquid particles havingnegligible fall-velocity/settling-velocity
2.8
aftercooling
removal of heat from the air after compression iscomplete
2.9
agglomerate
group of two or more particles combined, joined orformed into a cluster by any means
2.10
ambient temperature
temperature of the environment surrounding theequipment
2.11
attritionscouringscoring
wear caused by rubbing or friction
2.12
breakthrough
moment atwhich acontaminant is detecteddownstream of an adsorbent
2.13
brownian motion
random movement of very small particles (less than0,2 um) caused by bombardment of those particlesby gas molecules
Note 1 to entryAs a result of this random or spiralmovement,the particles describe paths much greaterthan their actual size and are, therefore, easier to trap.
2.14
channel
subset, defined by an upper and a lower limit, of data for the full spectral range of a particle counting instrument in which the particle counts are stored
2.15
coalescing
action of uniting small droplets
2.16
coincidence error
error which occurs because at a given time morethan one particle is contained in the measurementvolume of a particle counter
Note 1 to entry The coincidenceerror leads to ameasured number concentration which is too low and avalue for the mean particle diameter which is too high.
[SOURCE:EN 14799:2007,3.17]
2.17
colony-forming unitCFU
unit by which the culturable number is expressed
2.18
condensate
liquid formed in the compressed air
2.19
condensation
process of changing a vapour into liquid
2.20
contaminant
any solid, liquid, or gas,which adversely affects thesystem
[SOURCE: ISO 5598:2008，3.2.124,modified —The wording of the definiton has been modified.]
2.21
contamination level
amount of solid, liquid or gas present in thecompressed air
2.22
culturable number
number ofmicro-organisms, singlecellsoraggregates able to form colonies on a solid nutrientmedium
2.23cyclone
device for separating mixed size particles from agas stream by the use of a vortex
2.24
deliquescence
spontaneous process whereby a soluble solid material absorbs water and becomes liquid
2.25
depth type filtration
filtration accomplished by flowing a fluid through afilter medium providing a tortuous path to capturethe contaminants
2.26
desiccant
substance with the ability to remove water fromcompressed air
EXAMPLESilica gel (SiO2) or activated alumina(AlzO3).
2.27
desorption
physical process in which the molecules of a gas,vapour or liquid are removed from the surface of asolid
2.28
dew point
temperature at which water vapour begins tocondense
[SOURCE: ISO 5598:2008,3.2.196]
2.29
dew point,atmospheric
dew point at atmospheric pressure
2.30
dew point, pressure
dew point at the specified pressure
2.31
differential pressure
difference in value between two pressures occurringsimultaneously at different measurement points
[SOURCE: ISO 5598:2008,3.2.202]
2.32
diffusion
movement of gas molecules,or small particles,caused by a concentration gradient