ISO 13577-3:2016 工業炉および関連する処理装置—安全性—パート3：保護および反応性雰囲気ガスの生成と使用 | ページ 6

3.1

safety shutdown

function that takes the TPE out of operation and brings it in a defined safe state

Note 1 to entry: The definition is different from safety shutdown according ISO 13574:2015, 2.166 which is applicable to ISO 13577-2.

3.2

flame failure

loss of flame from the normally detected position by any cause other than the action of de-energising the automatic shut-off valves system

Note 1 to entry: The term is used in ISO 13577-2.

3.3

gas generator

equipment that converts or modifies a fluid or a mixture of fluids (gaseous or liquid) into a gas which can be utilized as the controlled atmosphere within the thermo-processing equipment

3.4

endothermic generator

gas generator that produces atmosphere gas by an endothermic reaction

3.5

exothermic generator

gas generator that produces atmosphere gas by an exothermic reaction

3.6

combustible atmosphere gas

any gas mixture that is capable of forming ignitable mixtures with air or oxygen under the conditions of temperature and pressure used in the process, according to the lower explosion level (LEL) of the actual gas mixture

3.7

inert gas

non-combustible gas which will not support combustion and does not react at all

Note 1 to entry: Nitrogen, helium and argon are typical inert gases.

3.8

purge gas

gas which can be used to purge a TPE

Note 1 to entry: A purge gas can safely be used for pre- and post-purging of cold and hot enclosures of TPE.

Note 2 to entry: Typically, purge gases are nitrogen, argon, helium and lean exothermic gas.

3.9

safety purge volume

volume of purge gas needed to displace either air or a combustible gas from a furnace chamber/enclosure to achieve a volume fraction of 1 % or less oxygen and/or a non-combustible atmosphere gas and/or 25 % of the lower flammability limit

Note 1 to entry: Typically, this will be a volume equal to five times the volume of the thermo-processing equipment chamber to be purged, if the purging gas is an inert gas.

Note 2 to entry: Non-combustible atmosphere gas as defined in 3.6.

3.10

multi-turn valve

valve which, in order to operate from the fully closed to the fully open position, requires a number of revolutions of the operating key or handwheel to be completed

3.11

safe ignition temperature

<MAC> minimum temperature at which spontaneous, safe auto-ignition of combustible gases occurs

Note 1 to entry: The safe ignition temperature has been established at 750 °C.

3.12

toxic atmosphere gas

gas which, in addition to having asphyxiating properties, also acts as a poison

3.13

internal gas generator

gas generator integrated into or directly connected to a TPE

3.14

gas control equipment

centralized mounting of components such as: pipework, safety components, pressure and flow accessories, assembled in a functional unit

3.15

atmosphere gas

gas that is supplied into or formed in TPE in accordance with a defined specification for thermo-processes

Note 1 to entry: Atmosphere gas is used to react with the material processed or to avoid a reaction with the material processed.

3.16

process liquids

liquids that are supplied to TPE to create an atmosphere gas