BS ISO 11057:2011 pdf free download Air quality — Test method for filtration characterization of cleanable filter media
1Scope
This International Standard specifies a standard reference test method for the comparative characterization ofpulse-jet cleanable filter media, to be used in filter elements (e.g. bag filters, pocket filters,cartridge filters)applied in dry gas cleaning under standardized test conditions.The main purpose of testing is to gaininformation about both the operational performance and the particle emission of cleanable filter media.
lt should be noted that while one test apparatus and operating method has been chosen and describedherein, it is recognized that other apparatus and operating arrangements can be found acceptable. In order fora candidate apparatus to become an equivalent apparatus,a comparison has to be performed with thestandard reference apparatus according to a specified procedure (6.1).The test procedure, the characteristicsof the required test facility, and the test conditions, as well as the evaluation and presentation of the results,are specified.
The results obtained from this test method are not intended for prediction of the absolute performance of full-scale filter facilities. However, they are helpful for the selection and development of appropriate cleanable fltermedia and the identification of suitable operating parameters.
Additional tasks such as verifying filter media concerning PM,s emissions , the classification of different mediaaccording to their filtration performance or the cleanability and durability of filter elements (i.e. projection ofbag lifetime) can be addressed using the test method specified.
2Terms and definitions
For the purposes of this document, the following terms and definitions apply.2.1
aerosol
suspension in a gaseous medium of solid particles,liquid particles or solid and liquid particles having anegligible falling velocity
[ISO 4225:1994[2],3.2]2.2
ageing
〈air quality) process applied to a filter medium to simulate long-term filter operationNOTE Examples of changes in process behaviour are pressure drop and cycle time.2.3
filter face velocity
flow rate (under operating conditions) of gas through the exposed flter area divided by that area
NOTE1 Other frequently used terms are: air-to-cloth ratio and gas-to-cloth ratio.
NOTE 2 Filter face velocity is often expressed in cubic metres per square metre hour, i.e. metres per hour. Alternativeunits are metres per minute or feet per minute (deprecated).
2.4
calibration
(air filtration characterization) comparison of a measuring device (e.g.an optical particle counter) with anotherinstrument for reference measurements using, for example, a reference test aerosol with the objective of anexact determination of an experimental parameter
2.5
clean gas
gas flow exiting the filter
2.6
cleanable filter medium
filter medium whose aerodynamic and particle collection characteristics are regeneratable or recoverable
2.7 Particle concentration
2.7.1
particle number concentration
(air filtration characterization) total number of particles per carrier gas volumeNOTE
Particle number concentration is expressed in particle numbers per cubic metre or reciprocal cubic metres.
2.7.2
particle mass concentration
total mass of particles per carrier gas volume
NOTE Particle number concentration is expressed in grams per cubic metre.
2.8
cycle time
《air quality) time between two cleaning pulses under defined operational conditions
2.9
detection limit of the clean gas concentration
(air fltration characterization,minimum concentration in the clean gas which can be unambiguouslydetermined by the described gravimetric method
2.10 dirty
gas
dust-loaded gas which is fed into the inlet side of the filter
2.11
dispersion air
gas flow necessary for the dispersion of test dust, i.e. for the transformation of test dust into an aerosolNOTE Dispersion air needs to be dry, oil-free, and at constant temperature and gas flow rate.
2.12
dust collection efficiency
mass of particulate material collected by the filter divided by the mass of inlet particulate material
2.13
equivalent particle diameter
(air filtration characterization) particle size obtained on the basis of a specific method of measurement, andexpressed in terms of the diameter of an “equivalent”sphere for that respective method
NOTE1 Examples of specific measurements are: projected area,surface area,volume,mass,settling velocity or