ISO 7504:2015 pdf download – Gas analysis— Vocabulary
ISO 7504:2015 pdf download – Gas analysis— Vocabulary.
temperature at or below which, at a specified pressure, condensation from the gas phase will occur
Note 1 to entry: For pure substances, dew point and bubble point (4.2) coincide. At that temperature, the pressure equals the saturation vapour pressure (4.).
pressure and temperature condition at which the liquid phase is in equilibrium with the first appearing bubbles of gas
Note Ito entry: For pure substances, dew point (4.6) and bubble point coincide. At that temperature, the pressure equals the saturation vapour pressure (4.5).
single point in pressure-temperature space at which the composition (3.5) and properties of the gas and liquid phases In equilibrium are identical
Note I to entry: The pressure at this point is known as the ‘critical pressure pt” and the temperature as the ‘critical temperature Ta”, respectively,
Note 2 to entry: For a pure substance, the critical temperature Is thai temperature above which only the gas phase can exist irrespective o the applied pressure.
maximum pressure at which two-phase separation (condensation) can occur
Note Ito entry: The phase coordinates cricondenbar and crlcondentherm (4J,) apply to gas mixtures (with the binary system as the simplest case). For a gas mixture, the critical point (4.) is no longer the maximum pressure, as well as the maximum temperature for vapour•hquld coexistence (see FIgure 1).
Note 2 to entry: It Is the highest pressure in thetwo’phase envelopeand generally higherthan thecritical pressure.
Note 3 to entry: For a pure substance, cricondentherm (4.11)). crlcondc’nbar, and critical point (4,11) are represented by a single point. i.e. the critical point.
maximum temperature at which two’phase separation (condensation) can occur
Note 1 to entry: The phase coordinates cricondenbar (4.2) and cricondentherm apply to gas mixtures (with the binary system as the simplest case). For a gas mixture, the crltkalpoint (4.) Is no longer the maximum pressure, as well as the maximum temperature for vapour-liquid coexistence (see Figure 1).
Note 2 to entry: It is the highest temperature in the two-phase envelope and generally higher than the critical temperature.
Note 3 to entry: For a pure substance, crlcondentherm, crkondenbar (4.9), and critical point (4.11) are represented by a single point. i.e. the critical point.
complementary gas balance gas diluent gas malor gas matrix gas
component (13) of a gas mixture which is usually added at the completing step of the mixture preparation or used as a diluent in preparation of the mixture by dynamic method (f.4)
Nore 1 to entry: Generally, the particular application of the gas mixture determines the selectIon of the complementary gas.
Note 2 to entry: The complementary gas may also be a mixture (e.g. air).
undesired minor component (3.3) present in a parent gas (,3) and thus detectable in a gas mixture made of this parent gas
impurity .illectlng the intended use of a gas mixture
Note ito entry: The criteria for a critical impurity are given in ISO 19229.
impurity that is predicted to contribute more than 10% of the target uncertainty in the final gas mixture
gas or gas mixture with sufficiently low content of the component(s) (3.3) of interest, used to produce the zero response (0.12) of a given Instrument for a given range of content (14)
6 Terms relating to methods for the preparation of gas mixtures
method in which the mass of each component (3.3) present is determined by weighing
method In which the content (14) of each component (13) present Is determined by the Increase of pressure after its addition
static volumetric method
method which combines known volumes of two or more gases at the same pressure and temperature
method which combines two or more gas streams having known [low rates Into a single stream under specific conditions (pressure and temperature to be specified).