ISO 20480-3:2021
(Main)Fine bubble technology — General principles for usage and measurement of fine bubbles — Part 3: Methods for generating fine bubbles
Fine bubble technology — General principles for usage and measurement of fine bubbles — Part 3: Methods for generating fine bubbles
This document describes methods for generating fine bubbles.
Technologie des fines bulles — Principes généraux pour l'utilisation et la mesure des fines bulles — Partie 3: Méthodes pour générer des fines bulles
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INTERNATIONAL ISO
STANDARD 20480-3
First edition
2021-09
Fine bubble technology — General
principles for usage and measurement
of fine bubbles —
Part 3:
Methods for generating fine bubbles
Technologie des fines bulles — Principes généraux pour l'utilisation et
la mesure des fines bulles —
Partie 3: Méthodes pour générer des fines bulles
Reference number
ISO 20480-3:2021(E)
© ISO 2021
---------------------- Page: 1 ----------------------
ISO 20480-3:2021(E)
COPYRIGHT PROTECTED DOCUMENT
© ISO 2021
All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication may
be reproduced or utilized otherwise in any form or by any means, electronic or mechanical, including photocopying, or posting on
the internet or an intranet, without prior written permission. Permission can be requested from either ISO at the address below
or ISO’s member body in the country of the requester.
ISO copyright office
CP 401 • Ch. de Blandonnet 8
CH-1214 Vernier, Geneva
Phone: +41 22 749 01 11
Email: copyright@iso.org
Website: www.iso.org
Published in Switzerland
ii
© ISO 2021 – All rights reserved
---------------------- Page: 2 ----------------------
ISO 20480-3:2021(E)
Contents Page
Foreword .iv
Introduction .v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Examples of methods for generating fine bubbles . 3
4.1 Swirling flow system (for microbubble generation) . 3
4.2 Static mixer system (for microbubble generation) . . 3
4.3 Ejector system . . 4
4.4 Venturi system . 5
4.5 Pressurized dissolution system (for microbubble generation) . 6
4.6 Mechanical shear system . 7
4.7 Micropore system . 8
4.8 Surfactant addition micropore system . 8
4.9 Microporous shear system. 9
4.10 Heat separation system . 10
4.11 Mixed vapor condensation system . 11
4.12 Swirling flow system (for ultra fine bubble generation) . 11
4.13 Pressurized dissolution system (for ultra fine bubble generation) .12
4.14 Static mixer system (for ultra fine bubble generation) . 13
4.15 Electrolytic system . 14
4.16 Ultrasound (cavitation) system . 15
4.17 Other methods . 15
Annex A (informative) Other examples of methods for generating fine bubbles .16
Bibliography .17
Index .18
iii
© ISO 2021 – All rights reserved
---------------------- Page: 3 ----------------------
ISO 20480-3:2021(E)
Foreword
ISO (the International Organization for Standardization) is a worldwide federation of national standards
bodies (ISO member bodies). The preparation work for International Standards is typically carried
out through ISO technical committees. Each member body interested in the subject which involves
a technical committee established has the right to be represented in that committee. International
organizations, the governmental and the non-governmental, in liaison with ISO, also take part in the
work. ISO closely collaborates with the International Electrotechnical Commission (IEC) on all the
matters related to electrotechnical standardization.
The procedures used to develop this document and those intended for its further maintenance are
described in the ISO/IEC Directives, Part 1. In particular, the different approval criteria needed for the
different types of ISO documents should be noted. This document was drafted in accordance with the
editorial rules of the ISO/IEC Directives, Part 2 (see www.iso.org/directives).
Attention is drawn to the possibility that some elements of this document may include patent rights.
ISO shall not be responsible for identifying any or all such patent rights. Details of any patent rights
identified during the development of the document will be described in the Introduction and/or on the
ISO list of patent declarations received (see www.iso.org/patents).
Any trade name used in this document is mere information given for the convenience of users and does
not constitute an endorsement.
For explaining the voluntary nature of standards, meanings of terms specific to ISO and
expressions related to conformity assessment, as well as information on ISO's adherence to
the World Trade Organization (WTO) principles in the Technical Barriers to Trade (TBT), see
www.iso.org/iso/foreword.html.
This document was prepared by ISO/TC 281, Fine bubble technology.
Any feedback or questions on this document should be directed to the user’s national standards body.
The complete list of these bodies is available at www.iso.org/members.html.
A list of all the parts in ISO 20480 series can be found on the ISO website.
iv
© ISO 2021 – All rights reserved
---------------------- Page: 4 ----------------------
ISO 20480-3:2021(E)
Introduction
Until now the terminology, method and corresponding technology for the generation of fine bubbles
have not been standardized. The new project to standardize the terminology of fine bubble generating
systems and the corresponding technology is thought to have significant influences on the market as
follows:
— convenience of customers when purchasing or using fine bubble generating system and its techniques
will be improved, and owing to the improvement of their convenience, it can be expected to boost
fine bubble industries;
— standardization of terminology will enhance commonality in the field of generating system
performance. Improvement in performances in hardware and software will also prospectively lead
to market growth of the manufacturing industries of fine bubble generating system;
— standardization of terminology will enable the application markets to be boosted in creating new
markets, as well as unifying existing markets.
In addition to existing fine bubble technology standards, by specifying "common terms" of generation
principles, it will allow best practices to use common terms for fine bubble generating systems as well
as the market expansion is expected.
v
© ISO 2021 – All rights reserved
---------------------- Page: 5 ----------------------
INTERNATIONAL STANDARD ISO 20480-3:2021(E)
Fine bubble technology — General principles for usage and
measurement of fine bubbles —
Part 3:
Methods for generating fine bubbles
1 Scope
This document describes methods for generating fine bubbles.
2 Normative references
The following documents are referred to in the text in the sense that some or all of their content
constitutes requirements of this document. For dated references, only the edition cited applies. For
undated references, the latest edition of the referenced document (including any amendments) applies.
ISO 20480-1, Fine bubble technology — General principles for usage and measurement of fine bubbles —
Part 1: Terminology
ISO 20480-2, Fine bubble technology — General principles for usage and measurement of fine bubbles —
Part 2: Categorization of the attributes of fine bubbles
3 Terms and definitions
For the purposes of this document, the terms and definitions given in ISO 20480-1 and ISO 20480-2,
and the following apply.
ISO and IEC maintain terminological databases for the use in standardization at the following addresses:
— ISO Online browsing platform: available at https:// www .iso .org/ obp
— IEC Electropedia: available at http:// www .electropedia .org/
3.1
flow path
passage that conveys fluid
[SOURCE: ISO 5598:2020, 3.2.302]
3.2
cavitation
formation and collapse of bubbles in a liquid when the pressure falls to or below the liquid vapour
pressure, the collapse releases energy, sometimes with an audible sound and vibration
[SOURCE: ISO 16904:2016, 3.7]
3.3
Venturi tube
device which consists of a convergent inlet which is conically connected to the cylindrical part called
the “throat” and an expanding section called “divergent” with a conical shape
1)
[SOURCE: ISO 5167-1:— , 3.2.5]
1) Under preparation. Stage at the time of publication ISO/DIS 5167-1:2021.
1
© ISO 2021 – All rights reserved
---------------------- Page: 6 ----------------------
ISO 20480-3:2021(E)
3.5
impeller
spinning disc in a centrifugal pump with protruding vanes, which is used to accelerate the fluid in the
pump casing
[SOURCE: ISO 13501:2011, 3.1.51]
3.6
solubility
maximum mass of a solute that can be dissolved in a unit volume of solution measured under equilibrium
conditions
[SOURCE: ISO 17327-1:2018, 3.16]
3.7
surfactant
surface active substance that reduces the surface tension of the solution
[SOURCE: ISO 8124-7:2015, 3.7]
3.8
critical micelle
state of maximum concentration of dispersing agent before micelles form
[SOURCE: ISO 14887:2000, 3.4]
3.9
ultrasound
high frequency (over 20 kHz) sound waves which propagate through fluids and solids
[SOURCE: ISO 20998-1:2006, 2.22]
3.10
self-priming
suction of fluid into flow path without using a mechanism for feeding pressure
3.11
nozzle
structure that accelerates and releases fluid
3.12
porous membrane
membrane containing pores (voids)
3.13
non-condensable gas
air and/or other gases which is not liquefied under the conditions of a saturated steam
[SOURCE: ISO 11139:2018, 3.183]
3.14
electrolysis
process in which electric current is used to promote a chemical reaction
Note 1 to entry: In the case of water, the separation reaction generating hydrogen and oxygen is a typical example.
[SOURCE: ISO/TR 15916:2015, 3.34]
2
© ISO 2021 – All rights reserved
---------------------- Page: 7 ----------------------
ISO 20480-3:2021(E)
4 Examples of methods for generating fine bubbles
4.1 Swirling flow system (for microbubble generation)
Liquid is made to swirl around the interior of a cylinder at a high speed, reducing the pressure near
the central axis of the cylinder and thereby causing gas to be sucked in from the outside. Within the
cylinder, centrifugal separation occurs where low-density gas is located at the centre and high-density
liquid is located at the cylinder wall. The gas column is pulverized by the fierce shear flow to produce
fine bubbles, see Figure 1.
Key
1 fine bubbles
2 liquid
3 gas column
4 swirling flow
5 gas
6 pump
Figure 1 — Schematic diagram of fine bubble generation using swirling flow system
4.2 Static mixer system (for microbubble generation)
This system does not use mechanical pulverization. The flow path has a complex structure, and the
circulatory drive force of the liquid produces a vortex flow which is primarily responsible for creating a
large viscous shear force that pulverizes the gas. Protrusions on the inner wall of the cylinder produce
vortex in the liquid flow, and the large bubbles carried along with the liquid are pulverized by the shear
force to produce fine bubbles, see Figure 2.
3
© ISO 2021 – All rights reserved
---------------------- Page: 8 ----------------------
ISO 20480-3:2021(E)
Key
1 fine bubbles
2 blade
3 gas column
4 guide vanes
5 gas
6 liquid
7 obstructions
Figure 2 — Schematic diagram of fine bubble generation using static mixer system
4.3 Ejector system
This system uses sudden narrowing and widening of the flow p
...
FINAL
INTERNATIONAL ISO/FDIS
DRAFT
STANDARD 20480-3
ISO/TC 281
Fine bubble technology — General
Secretariat: JISC
principles for usage and measurement
Voting begins on:
2021-06-24 of fine bubbles —
Voting terminates on:
Part 3:
2021-08-19
Methods for generating fine bubbles
Technologie des fines bulles — Principes généraux pour l'utilisation et
la mesure des fines bulles —
Partie 3: Méthodes pour générer des fines bulles
RECIPIENTS OF THIS DRAFT ARE INVITED TO
SUBMIT, WITH THEIR COMMENTS, NOTIFICATION
OF ANY RELEVANT PATENT RIGHTS OF WHICH
THEY ARE AWARE AND TO PROVIDE SUPPOR TING
DOCUMENTATION.
IN ADDITION TO THEIR EVALUATION AS
Reference number
BEING ACCEPTABLE FOR INDUSTRIAL, TECHNO-
ISO/FDIS 20480-3:2021(E)
LOGICAL, COMMERCIAL AND USER PURPOSES,
DRAFT INTERNATIONAL STANDARDS MAY ON
OCCASION HAVE TO BE CONSIDERED IN THE
LIGHT OF THEIR POTENTIAL TO BECOME STAN-
DARDS TO WHICH REFERENCE MAY BE MADE IN
©
NATIONAL REGULATIONS. ISO 2021
---------------------- Page: 1 ----------------------
ISO/FDIS 20480-3:2021(E)
COPYRIGHT PROTECTED DOCUMENT
© ISO 2021
All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication may
be reproduced or utilized otherwise in any form or by any means, electronic or mechanical, including photocopying, or posting
on the internet or an intranet, without prior written permission. Permission can be requested from either ISO at the address
below or ISO’s member body in the country of the requester.
ISO copyright office
CP 401 • Ch. de Blandonnet 8
CH-1214 Vernier, Geneva
Phone: +41 22 749 01 11
Email: copyright@iso.org
Website: www.iso.org
Published in Switzerland
ii © ISO 2021 – All rights reserved
---------------------- Page: 2 ----------------------
ISO/FDIS 20480-3:2021(E)
Contents Page
Foreword .iv
Introduction .v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Examples of methods for generating fine bubbles . 3
4.1 Swirling flow system (for microbubble generation) . 3
4.2 Static mixer system (for microbubble generation). 3
4.3 Ejector system . 4
4.4 Venturi system . 5
4.5 Pressurized dissolution system (for microbubble generation) . 6
4.6 Mechanical shear system . 7
4.7 Micropore system . 8
4.8 Surfactant addition micropore system . 9
4.9 Microporous shear system.10
4.10 Heat separation system .11
4.11 Mixed vapor condensation system .12
4.12 Swirling flow system (for ultra fine bubble generation) .12
4.13 Pressurized dissolution system (for ultra fine bubble generation) .13
4.14 Static mixer system (for ultra fine bubble generation) .14
4.15 Electrolytic system .15
4.16 Ultrasound (cavitation) system .16
4.17 Other methods .17
Annex A (informative) Other examples of methods for generating fine bubbles .18
Bibliography .19
© ISO 2021 – All rights reserved iii
---------------------- Page: 3 ----------------------
ISO/FDIS 20480-3:2021(E)
Foreword
ISO (the International Organization for Standardization) is a worldwide federation of national standards
bodies (ISO member bodies). The preparation work for International Standards is typically carried
out through ISO technical committees. Each member body interested in the subject which involves
a technical committee established has the right to be represented in that committee. International
organizations, the governmental and the non-governmental, in liaison with ISO, also take part in the
work. ISO closely collaborates with the International Electrotechnical Commission (IEC) on all the
matters related to electrotechnical standardization.
The procedures used to develop this document and those intended for its further maintenance are
described in the ISO/IEC Directives, Part 1. In particular, the different approval criteria needed for the
different types of ISO documents should be noted. This document was drafted in accordance with the
editorial rules of the ISO/IEC Directives, Part 2 (see www .iso .org/ directives).
Attention is drawn to the possibility that some elements of this document may include patent rights.
ISO shall not be responsible for identifying any or all such patent rights. Details of any patent rights
identified during the development of the document will be described in the Introduction and/or on the
ISO list of patent declarations received (see www .iso .org/ patents).
Any trade name used in this document is mere information given for the convenience of users and does
not constitute an endorsement.
For explaining the voluntary nature of standards, meanings of terms specific to ISO and expressions
related to conformity assessment, as well as information on ISO's adherence to the World Trade
Organization (WTO) principles in the Technical Barriers to Trade (TBT), see www .iso .org/ iso/ foreword
.html.
This document was prepared by ISO/TC 281, Fine bubble technology.
Any feedback or questions on this document should be directed to the user’s national standards body.
The complete list of these bodies is available at www .iso .org/ members .html.
A list of all the parts in ISO 20480 series can be found on the ISO website.
iv © ISO 2021 – All rights reserved
---------------------- Page: 4 ----------------------
ISO/FDIS 20480-3:2021(E)
Introduction
Until now the terminology, method and corresponding technology for the generation of fine bubbles
have not been standardized. The new project to standardize the terminology of fine bubble generating
systems and the corresponding technology is thought to have significant influences on the market as
follows:
— convenience of customers when purchasing or using fine bubble generating system and its techniques
will be improved, and owing to the improvement of their convenience, it can be expected to boost
fine bubble industries;
— standardization of terminology will enhance commonality in the field of generating system
performance. Improvement in performances in hardware and software will also prospectively lead
to market growth of the manufacturing industries of fine bubble generating system;
— standardization of terminology will enable the application markets to be boosted in creating new
markets, as well as unifying existing markets.
In addition to existing fine bubble technology standards, by specifying "common terms" of generation
principles, it will allow best practices to use common terms for fine bubble generating systems as well
as the market expansion is expected.
© ISO 2021 – All rights reserved v
---------------------- Page: 5 ----------------------
FINAL DRAFT INTERNATIONAL STANDARD ISO/FDIS 20480-3:2021(E)
Fine bubble technology — General principles for usage and
measurement of fine bubbles —
Part 3:
Methods for generating fine bubbles
1 Scope
This document describes methods for generating fine bubbles.
2 Normative references
The following documents are referred to in the text in the sense that some or all of their content
constitutes requirements of this document. For dated references, only the edition cited applies. For
undated references, the latest edition of the referenced document (including any amendments) applies.
ISO 20480-1, Fine bubble technology — General principles for usage and measurement of fine bubbles —
Part 1: Terminology
ISO 20480-2, Fine bubble technology — General principles for usage and measurement of fine bubbles —
Part 2: Categorization of the attributes of fine bubbles
3 Terms and definitions
For the purposes of this document, the terms and definitions given in ISO 20480-1 and ISO 20480-2,
and the following apply.
ISO and IEC maintain terminological databases for the use in standardization at the following addresses:
— ISO Online browsing platform: available at https:// www .iso .org/ obp
— IEC Electropedia: available at http:// www .electropedia .org/
3.1
flow path
passage that conveys fluid
[SOURCE: ISO 5598:2020, 3.2.302]
3.2
cavitation
formation and collapse of bubbles in a liquid when the pressure falls to or below the liquid vapour
pressure, the collapse releases energy, sometimes with an audible sound and vibration
[SOURCE: ISO 16904:2016, 3.7]
3.3
Venturi tube
device which consists of a convergent inlet which is conically connected to the cylindrical part called
the “throat” and an expanding section called “divergent” with a conical shape
1)
[SOURCE: ISO 5167-1:— , 3.2.5]
1) Under preparation. Stage at the time of publication ISO/DIS 5167-1:2021.
© ISO 2021 – All rights reserved 1
---------------------- Page: 6 ----------------------
ISO/FDIS 20480-3:2021(E)
3.5
impeller
spinning disc in a centrifugal pump with protruding vanes, which is used to accelerate the fluid in the
pump casing
[SOURCE: ISO 13501:2011, 3.1.51]
3.6
solubility
maximum mass of a solute that can be dissolved in a unit volume of solution measured under equilibrium
conditions
[SOURCE: ISO 17327-1:2018, 3.16]
3.7
surfactant
surface active substance that reduces the surface tension of the solution
[SOURCE: ISO 8124-7:2015, 3.7]
3.8
critical micelle
state of maximum concentration of dispersing agent before micelles form
[SOURCE: ISO 14887:2000, 3.4]
3.9
ultrasound
high frequency (over 20 kHz) sound waves which propagate through fluids and solids
[SOURCE: ISO 20998-1:2006, 2.22]
3.10
self-priming
suction of fluid into flow path without using a mechanism for feeding pressure
3.11
nozzle
structure that accelerates and releases fluid
3.12
porous membrane
membrane containing pores (voids)
3.13
non-condensable gas
air and/or other gases which is not liquefied under the conditions of a saturated steam
[SOURCE: ISO 11139:2018, 3.183]
3.14
electrolysis
process in which electric current is used to promote a chemical reaction
Note 1 to entry: In the case of water, the separation of hydrogen from oxygen is taken as an example.
[SOURCE: ISO/TR 15916:2015, 3.34]
2 © ISO 2021 – All rights reserved
---------------------- Page: 7 ----------------------
ISO/FDIS 20480-3:2021(E)
4 Examples of methods for generating fine bubbles
4.1 Swirling flow system (for microbubble generation)
Liquid is made to swirl around the interior of a cylinder at a high speed, reducing the pressure near
the central axis of the cylinder and thereby causing gas to be sucked in from the outside. Within the
cylinder, centrifugal separation occurs where low-density gas is located at the centre and high-density
liquid is located at the cylinder wall. The gas column is pulverized by the fierce shear flow to produce
fine bubbles, see Figure 1.
Key
1 fine bubbles
2 liquid
3 gas column
4 swirling flow
5 gas
6 pump
Figure 1 — Schematic diagram of fine bubble generation using swirling flow system
4.2 Static mixer system (for microbubble generation)
This system does not use mechanical pulverization. The flow path has a complex structure, and the
circulatory drive force of the liquid produces a vortex flow which is primarily responsible for creating a
large viscous shear force that pulverizes the gas. Protrusions on the inner wall of the cylinder produce
vortex in the liquid flow, and the large bubbles carried along with the liquid are pulverized by the shear
force to produce fine bubbles, see Figure 2.
© ISO 2021 – All rights reserved 3
---------------------- Page: 8 ----------------------
ISO/FDIS 20480-3:2021(E)
Key
1 fine bubbles
2 blade
3 gas column
4 guide vanes
5 gas
6 liquid
7 obstructions
Figure 2 — Schematic diagram of fine bubble generation using static mixer system
4.3 Ejector system
This system uses sudden narrowing and widening of the flow path, pro
...
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