ISO 21910-1-2020 pdf free.Fine bubble technology — Characterization of microbubbles — Off-line evaluation of size index.
1.This document specifies the evaluation method for the size index of microbubbles in microbubbledispersion. It is only applicable to microbubbles with or without shell in water within the rangefrom 1 um to 100 um. It describes the sampling methods from the point generating or dispersingmicrobubbles in the retention container to the detecting point of the measuring instruments.
2.Normative references:There are no normative references in this document.
3.Terms and definitions:For the purposes of this document, the following terms and definitions apply.
3.1
measurement time
period for a sequence of measuring process,whereas the size index and/or the number concentrationindex of the microbubbles can be assumed stable all through the period and reproducible over theperiods with similar measurement condition
Note 1 to entry: Measurement time is described by the starting time and the ending time, or by either of them andthe duration.
3.2.water diluent:homogeneous water which is used for dilution without causing any deleterious effects and whosenumber concentration of ultrafine bubbles is known.
Note 1 to entry: Water diluent is used to decrease the number concentration of ultrafine bubbles in a dispersionwithout changing their total number, state of aggregation with particles, size or surface chemistry.
Note 2 to entry: Water diluent is called blank water when its number concentration of ultrafine bubbles is knownto be zero and when it is used for the evaluation of ultrafine bubbles.[SOURCE: ISO 20298-1:2018,3.2]
3.3.retention time:period from the point generating or dispersing microbubbles in the retention container to the detectingpoint of the measuring instruments.
4.1 Requirements on the sample
Microbubbles should be present in pure water or can be in tap water if the numbers of contaminantparticles are much lower than those of microbubbles. The microbubbles should contain air, nitrogenand oxygen.In cases where they are surrounded with a coating, e.g. a lipid, other gas can be applied.The size range of microbubbles that can be measured depends on the specification of the measuringinstrument to be used as is the number or volume concentration range of microbubbles.The reliabilityof the results shall be confirmed for each measuring instrument.
Microbubbles which diameter is equal or larger than 10 um should be measured promptly (see 7.6.1).Microbubbles less than 10 um and microbubbles with shell may not need to be measured quickly.Thisclassification is referred to in ISO 20480-2.
4.2 Requirements on the sample transfer and measurement system
An appropriate sample transfer and measurement system which connects a microbubble generatingsystem and a measuring instrument enable to characterize unstable microbubble dispersion in wateras a size index.Because of the low bubble stability of microbubbles without shell and the decrease indispersibility of microbubbles with shell, it is recommended to have the measuring instrument in thevicinity of either the generating system or the dispersing system.The size index of microbubbles should be determined just after the sample transfer.Signal acquisitiontime of measuring instrument should be set at a minimum interval which is necessary for the detectionof sufficient signals from the microbubbles to determine its size index with good reproducibility.Beforeloading the sample into a measuring instrument, clean the inside of a generating system by rinsing itseveral times with water diluent to remove contaminants.Attention should be paid to avoid microbubbles to adhere to the inside of the tube which is used forloading to the measuring instrument.Before each measurement, it should be confirmed if microbubbles are dispersed homogeneously orsaturated in water at a trial run.ISO 21910 pdf download.