prEN ISO 21049
(Main)Pumps - Shaft-sealing systems for centrifugal and rotary pumps (ISO/DIS 21049:2010)
Pumps - Shaft-sealing systems for centrifugal and rotary pumps (ISO/DIS 21049:2010)
2018-06-15 Project abandoned as ISO abandoned the project.
Pumpen - Wellendichtungssysteme für Kreiselpumpen und rotierende Verdrängerpumpen (ISO/DIS 21049:2010)
Pompes - Dispositifs d'étanchéité de l'arbre pour pompes centrifuges et rotatives (ISO/DIS 21049:2010)
Črpalke - Sistemi grednih tesnilk za centrifugalne in rotacijske črpalke (ISO/DIS 21049:2010)
General Information
Relations
Standards Content (Sample)
SLOVENSKI STANDARD
01-maj-2010
ýUSDONH6LVWHPLJUHGQLKWHVQLON]DFHQWULIXJDOQHLQURWDFLMVNHþUSDONH ,62',6
Pumps - Shaft-sealing systems for centrifugal and rotary pumps (ISO/DIS 21049:2010)
Pumpen - Wellendichtungssysteme für Kreiselpumpen und rotierende
Verdrängerpumpen (ISO/DIS 21049:2010)
Pompes - Dispositifs d'étanchéité de l'arbre pour pompes centrifuges et rotatives
(ISO/DIS 21049:2010)
Ta slovenski standard je istoveten z: prEN ISO 21049
ICS:
21.140 Tesnilke, mašilke Seals, glands
23.080 ýUSDONH Pumps
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.
EUROPEAN STANDARD
DRAFT
NORME EUROPÉENNE
EUROPÄISCHE NORM
March 2010
ICS 83.140.50; 23.080; 23.100.60 Will supersede EN ISO 21049:2004
English Version
Pumps - Shaft-sealing systems for centrifugal and rotary pumps
(ISO/DIS 21049:2010)
Pompes - Dispositifs d'étanchéité de l'arbre pour pompes Pumpen - Wellendichtungssysteme für Kreiselpumpen und
centrifuges et rotatives (ISO/DIS 21049:2010) rotierende Verdrängerpumpen (ISO/DIS 21049:2010)
This draft European Standard is submitted to CEN members for parallel enquiry. It has been drawn up by the Technical Committee
CEN/TC 12.
If this draft becomes a European Standard, CEN members are bound to comply with the CEN/CENELEC Internal Regulations which
stipulate the conditions for giving this European Standard the status of a national standard without any alteration.
This draft European Standard was established by CEN in three official versions (English, French, German). A version in any other language
made by translation under the responsibility of a CEN member into its own language and notified to the CEN Management Centre has the
same status as the official versions.
CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia,
Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland,
Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland and United Kingdom.
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 supporting documentation.
Warning : This document is not a European Standard. It is distributed for review and comments. It is subject to change without notice and
shall not be referred to as a European Standard.
EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION
EUROPÄISCHES KOMITEE FÜR NORMUNG
Management Centre: Avenue Marnix 17, B-1000 Brussels
© 2010 CEN All rights of exploitation in any form and by any means reserved Ref. No. prEN ISO 21049:2010: E
worldwide for CEN national Members.
Contents Page
Foreword .3
Foreword
This document (prEN ISO 21049:2010) has been prepared by Technical Committee ISO/TC 115 "Pumps" in
collaboration with Technical Committee CEN/TC 12 “Materials, equipment and offshore structures for
petroleum, petrochemical and natural gas industries” the secretariat of which is held by AFNOR.
This document is currently submitted to the parallel Enquiry.
This document will supersede EN ISO 21049:2004.
Endorsement notice
The text of ISO/DIS 21049:2010 has been approved by CEN as a prEN ISO 21049:2010 without any
modification.
DRAFT INTERNATIONAL STANDARD ISO/DIS 21049
ISO/TC 115/SC 3 Secretariat: ANSI
Voting begins on: Voting terminates on:
2010-03-25 2010-08-25
INTERNATIONAL ORGANIZATION FOR STANDARDIZATION • МЕЖДУНАРОДНАЯ ОРГАНИЗАЦИЯ ПО СТАНДАРТИЗАЦИИ • ORGANISATION INTERNATIONALE DE NORMALISATION
Pumps — Shaft-sealing systems for centrifugal and rotary
pumps
Pompes — Dispositifs d'étanchéité de l'arbre pour pompes centrifuges et rotatives
[Revision of first edition (ISO 21049:2004)]
ICS 23.080; 23.100.60; 83.140.50
ISO/CEN PARALLEL PROCESSING
This draft has been developed within the International Organization for Standardization (ISO), and
processed under the ISO-lead mode of collaboration as defined in the Vienna Agreement.
This draft is hereby submitted to the ISO member bodies and to the CEN member bodies for a parallel
five-month enquiry.
Should this draft be accepted, a final draft, established on the basis of comments received, will be
submitted to a parallel two-month approval vote in ISO and formal vote in CEN.
To expedite distribution, this document is circulated as received from the committee secretariat.
ISO Central Secretariat work of editing and text composition will be undertaken at publication
stage.
Pour accélérer la distribution, le présent document est distribué tel qu'il est parvenu du
secrétariat du comité. Le travail de rédaction et de composition de texte sera effectué au
Secrétariat central de l'ISO au stade de publication.
THIS DOCUMENT IS A DRAFT CIRCULATED FOR COMMENT AND APPROVAL. IT IS THEREFORE SUBJECT TO CHANGE AND MAY NOT BE
REFERRED TO AS AN INTERNATIONAL STANDARD UNTIL PUBLISHED AS SUCH.
IN ADDITION TO THEIR EVALUATION AS BEING ACCEPTABLE FOR INDUSTRIAL, TECHNOLOGICAL, COMMERCIAL AND USER PURPOSES, DRAFT
INTERNATIONAL STANDARDS MAY ON OCCASION HAVE TO BE CONSIDERED IN THE LIGHT OF THEIR POTENTIAL TO BECOME STANDARDS TO
WHICH REFERENCE MAY BE MADE IN NATIONAL REGULATIONS.
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 SUPPORTING DOCUMENTATION.
©
International Organization for Standardization, 2010
ISO/DIS 21049
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©
ii ISO 2010 – All rights reserved
ISO/DIS 21049
Contents Page
Foreword . vi
Introduction . vii
1 Scope . 8
2 Normative References . 8
3 Terms and Definitions . 10
4 Sealing systems . 22
4.1 Seal categories, types and arrangements . 22
4.2 Objectives . 24
4.3 Specifying and/or purchasing a sealing system . 24
5 General . 32
5.1 Unit responsibility . 32
5.2 Dimensions. 32
6 Design requirements . 32
6.1 Common design requirements (all categories) . 32
6.2 Design requirements (category-specific) . 59
7 Specific seal configurations . 62
7.1 Arrangement 1 seals . 62
7.2 Arrangement 2 seals . 63
7.3 Arrangement 3 seals . 66
8 Accessories . 69
8.1 General . 69
8.2 Piping for seal auxiliary systems . 71
8.3 Components of Seal Auxiliary Systems (if specified per Annex G) . 75
9 Instrumentation . 90
9.1 General . 90
9.2 Temperature-indicating gauges . 90
9.3 Thermowells . 91
9.4 Pressure indicators. 91
9.5 Transmitters and Switches . 91
9.6 Level indicators . 92
9.7 Flow instruments . 92
9.8 Relief valves . 93
9.9 Pressure control valves . 93
9.10 Pressure amplifiers . 93
10 Inspection, testing and preparation for shipment . 94
10.1 General . 94
10.2 Inspection . 94
10.3 Testing . 95
10.4 Preparation for shipment . 100
11 Data transfer . 101
11.1 General . 101
11.2 Data Requirement Forms . 102
11.3 Data Sheet . 102
11.4 Inspector Checklist . 102
Annex A (informative) Recommended seal selection procedure . 103
A.1 Assumptions and instructions . 103
DRAFT 2010
ISO/DIS 21049
A.2 Tutorial clause . 119
A.3 Tutorial seal selection — Sheet 6 . 124
A.4 Alternative seal Arrangement selection method using Material Safety Data Sheet
information. . 125
Annex B (informative) Typical materials and material specifications for seal chamber and
mechanical seal components . 134
B.1 Materials standards . 134
B.2 Seal rings and mating rings . 141
B.3 Secondary seals . 145
B.4 Throat and throttle bushings . 150
Annex C (informative) Mechanical seal data sheets . 152
Annex D (informative) Seal codes . 157
D.1 Introduction . 157
Mechanical seal coding construction . 157
D.3 Historical mechanical seal codes . 160
Annex E (informative) Intentionally Left Blank . 163
Annex F (informative) Technical tutorials and illustrative calculations . 164
F.1 Seal leakage and leakage management . 164
F.2 Seal chamber temperature rise and flush . 170
F.3 Cartridge sleeve drive collar set screw loading . 206
F.4 Rotating or stationary flexible element selection . 209
F.5 Throat and throttle bushings . 211
Annex G (normative) Standard flush plans and auxiliary hardware . 213
G.1 General . 213
G.2 Symbol library . 214
G.3 Plan 01 . 216
G.4 Plan 02 . 217
G.5 Plan 11 . 218
G.6 Plan 12 . 219
G.7 Plan 13 . 220
G.8 Plan 14 . 221
G.9 Plan 21 . 222
G.10 Plan 22 . 223
G.11 Plan 23 . 224
G.12 Plan 31 . 225
G.13 Plan 32 . 226
G.14 Plan 41 . 228
G.15 Plan 51 . 229
G.16 Plan 52 . 230
G.17 Plan 53A . 232
G.18 Plan 53B . 234
G.19 Plan 53C . 236
G.20 Plan 54A . 238
G.21 Plan 54B . 239
G.22 Plan 61 . 240
G.23 Plan 62 . 241
G.24 Plan 65A . 242
G.25 Plan 65B . 244
G.26 Plan 71 . 245
G.27 Plan 72 . 246
G.28 Plan 74 . 247
G.29 Plan 75 . 249
G.30 Plan 76 . 251
G.31 Plan 99 . 252
G.32 External barrier/buffer fluid reservoir . 252
G.33 Plan 23 circulation system . 255
G.34 Barrier/buffer fluid reservoir . 256
iv © ISO 2009 – All rights reserved
DRAFT 2010
ISO/DIS 21049
Annex H (informative) Inspectors' checklist for all seals . 259
Annex I (normative) Seal qualification testing protocol . 260
I.1 General . 260
I.2 Hierarchy and attributes of sealing systems . 263
I.3 Scope of test . 265
I.4 Test procedure . 269
Annex J (normative) Mechanical seals data requirement forms . 285
Bibliography . 288
DRAFT 2010
ISO/DIS 21049
Foreword
ISO (the International Organization for Standardization) is a worldwide federation of national standards bodies
(ISO member bodies). The work of preparing International Standards is normally carried out through ISO
technical committees. Each member body interested in a subject for which a technical committee has been
established has the right to be represented on that committee. International organizations, governmental and
non-governmental, in liaison with ISO, also take part in the work. ISO collaborates closely with the
International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization.
International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 2.
The main task of technical committees is to prepare International Standards. Draft International Standards
adopted by the technical committees are circulated to the member bodies for voting. Publication as an
International Standard requires approval by at least 75 % of the member bodies casting a vote.
Attention is drawn to the possibility that some of the elements of this document may be the subject of patent
rights. ISO shall not be held responsible for identifying any or all such patent rights.
ISO 21049 was prepared by Technical Committee ISO/TC 115, Pumps, Subcommittee SC 3, Installation and
special applications, in collaboration with Technical Committee ISO/TC 67, Materials, equipment and offshore
structures for petroleum, petrochemical and natural gas industries, SC 6, Processing equipment and systems.
This second edition cancels and replaces the first edition (ISO 21049:2004), which has been technically
revised.
vi © ISO 2009 – All rights reserved
DRAFT 2010
ISO/DIS 21049
Introduction
This International Standard is based on the accumulated knowledge and experience of manufacturers and
users of equipment in the petroleum, natural gas and chemical industries, but its use is not restricted to these
industries.
Users of this International Standard should be aware that further or differing requirements may be needed for
individual applications. This International Standard is not intended to inhibit a vendor from offering, or the
purchaser from accepting, alternative equipment or engineering solutions for the individual application. This
may be particularly appropriate where there is innovative or developing technology. Where an alternative is
offered, the vendor should identify any variations from this International Standard and provide details.
The purpose of this International Standard is to assist purchasers with the selection and operation of
mechanical seals for pumps.
In this International Standard, where practical, US Customary units are included in brackets for information.
A bullet (z) at the beginning of a clause or subclause indicates that either a decision is required or further
information is to be provided by the purchaser. This information should be indicated on data sheets or stated
in the enquiry or purchase order (see examples in Annex C).
DRAFT 2010
ISO/DIS 21049
Pumps — Shaft-sealing systems for centrifugal and rotary
pumps
1 Scope
This International Standard specifies requirements and gives recommendations for sealing
systems for centrifugal and rotary pumps used in the petroleum, natural gas and chemical
industries. It is applicable mainly for hazardous, flammable and/or toxic services where a greater
degree of reliability is required for the improvement of equipment availability and the reduction of
both emissions to the atmosphere and life-cycle sealing costs. It covers seals for pump shaft
diameters from 20 mm (0,75 in) to 110 mm (4,3 in).
This International Standard is also applicable to seal spare parts and can be referred to for the
upgrading of existing equipment. A classification system for the seal configurations covered by
this International Standard into categories, types, arrangements and orientations is provided.
This International Standard is a stand-alone seal standard and is referenced normatively in
ISO 13709. It is applicable to both new and retrofitted pumps, and to pumps other than
ISO 13709 pumps (e.g. ASME B73.1, ASME B73.2 and API 676 pumps).
This International Standard might also be referenced by other machinery standards such as other
pumps, compressors and agitators. Users are cautioned that this International Standard is not
specifically written to address all of the potential applications that a purchaser may specify. This is
especially true for the size envelope specified for ISO 21049 seals. The purchaser and seal
vendor shall mutually agree on the features taken from this International Standard and used in
the application.
2 Normative References
The following referenced documents are indispensable for the application 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 7 (all parts), Pipe threads where pressure-tight joints are made on the threads
ISO 261, ISO general-purpose metric screw threads — General plan
ISO 262, ISO general-purpose metric screw threads — Selected sizes for screws, bolts, and nuts
ISO 286-2, ISO system of limits and fits — Part 2: Tables of standard tolerance grades and limit
deviations for holes and shafts
ISO 724, ISO general-purpose metric screw threads — Basic dimensions
ISO 965 (all parts), ISO general-purpose metric screw threads — Tolerances
8 © ISO 2009 – All rights reserved
DRAFT 2010
ISO/DIS 21049
ISO 7005-1, Metallic flanges — Part 1: Steel flanges
ISO 10438 (all parts), Petroleum, petrochemical and natural gas industries — Lubrication, Shaft-
sealing and control-oil systems and auxiliaries
ISO 13709, Centrifugal pumps for petroleum, petrochemical and natural gas industries
ISO 15649, Petroleum and natural gas industries — Piping
IEC 60079 (all parts), Electrical apparatus for explosive gas atmospheres
IEC 60529, Degrees of protection provided by enclosures (IP code)
1)
AISI, Standards, codes and specifications of the American Iron and Steel Institute
API RP 520 (all parts), Sizing, selection, and installation of pressure-relieving devices in
2)
refineries
API Std 526, Flanged steel pressure relief valves
3)
ASME V, ASME Boiler and pressure vessel code, Section V, Non-destructive examination
ASME VIII, ASME Boiler and pressure vessel code, Section VIII, Rules for the construction of
pressure vessels
ASME IX, ASME Boiler and pressure vessel code, Section IX, Welding and brazing qualifications
ASME B1.1, Unified inch screw threads (UN and UNR thread form)
ASME B1.20.1, Pipe threads, general purpose, inch
ASME B16.11, Forged fittings, socket-welding and threaded
ASME B16.20, Metallic gaskets for pipe flanges — Ring joint, spiral-wound, and jacketed
ASME B31.3, Process Piping
ASME B73.1, Specification for horizontal end suction centrifugal pumps for chemical process
ASME B73.2, Specification for vertical in-line centrifugal pumps for chemical process
ASME PTC 8.2, Centrifugal pumps, performance test codes
4)
AWS D1.1, Structural welding code — Steel
1)
Available from the American Iron and Steel Institute: 1140 Connecticut Ave., Suite 705, Washington, D.C.
20036, USA.
2)
Available from the American Petroleum Institute, 1220 L Street, NW, Washington, D.C. 20005-4070,
USA.
3)
Available from the American Society of Mechanical Engineers: Three Park Avenue, New York, NY
10016-5990, USA.
DRAFT 2010
ISO/DIS 21049
5)
EN 287 (all parts), Approval testing of welders — Fusion welding
EN 288 (all parts), Specification and approval of welding procedures for metallic materials
EN 13445 (all parts), Unfired pressure vessels
EPA Method 21, Appendix A of Title 40, Part 60 of the U.S. Code of Federal Regulations,
6)
Environmental Protection Agency, United States
7)
NEMA 250, Enclosures for electrical equipment (1 000 volts maximum)
8)
NFPA 70, National Electrical Code
Title 1, Part A, Section 112, U.S. National Emission Standards for Hazardous Air Pollutants
(NESHAPs) (Clean Air Act Amendment)
3 Terms and Definitions
For the purposes of this document, the following terms and definitions apply.
3.1
anti-rotation device
device used to prevent rotation of one component relative to an adjacent component in a seal
assembly
EXAMPLES Key, pin.
3.2
arrangement 1 seal
see 4.1.4
3.3
arrangement 2 seal
see 4.1.4
3.4
arrangement 3 seal
see 4.1.4
4)
Available from the American Welding Society, 550 N.W. Le Jeune Rd, Miami, FL 33126, USA.
5)
Comité Européen de Normalisation, 36, rue de Stassart, B-1050 Brussels, Belgium.
6)
Available from the National Archives and Records Administration, 700 Pennsylvania Avenue, N.W.,
Washington, D.C. 20408, USA.
7) th
Available from the National Electrical Manufacturers Association, 1300 North 17 Street, Rosslyn, VA
22209, USA.
8)
Available from the National Fire Protection Association, 1 Batterymarch Park, P.O. Box 9101, Quincy,
MA 02269-9101, USA.
9)
Environmental Protection Agency, Ariel Rios Building, 1200 Pennsylvania Avenue, N.W., Mail Code
3213A, Washington, D.C. 20460, USA.
10 © ISO 2009 – All rights reserved
DRAFT 2010
ISO/DIS 21049
3.5
atmospheric leakage collector
external reservoir arranged to capture liquid seal leakage from an arrangement 1 seal
3.6
auxiliary sleeve
separate sleeve mounted on the outer diameter of the seal shaft sleeve that facilitates assembly
of seal components.
3.7
back-to-back configuration
dual seal in which both of the flexible elements are mounted between the mating ring. The sealed
fluid is on the ID of the inner seal and the barrier or buffer fluid is on the OD of the inner and outer
seal.
3.8
balanced seal
mechanical seal in which the fluid closing forces have been modified through seal design
NOTE In this International Standard the seal balance ratio is less than 1 (see balance ratio calculation
in Annex F).
3.9
barrier fluid
externally supplied fluid at a pressure above the pump seal chamber pressure, introduced into an
Arrangement 3 seal to completely isolate the process liquid from the environment
3.10
barrier/buffer seal chamber
component or aggregate of components which form the cavity into which the outer seal of a
pressurized or unpressurized dual seal is installed and in which a barrier or buffer fluid is
circulated.
3.11
bellows seal
type of mechanical seal which uses a flexible metal bellows to provide secondary sealing and
spring loading
3.12
buffer fluid
externally supplied fluid, at a pressure lower than the pump seal chamber pressure, used as a
lubricant and/or to provide a diluent in an Arrangement 2 seal
3.13
cartridge seal
completely self-contained unit (including seal faces, flexible elements, seal gland plate sleeve
which is pre-assembled and preset before installation
3.14
category 1 seal
see 4.1.2
DRAFT 2010
ISO/DIS 21049
3.15
category 2 seal
see 4.1.2
3.16
category 3 seal
see 4.1.2
3.17
connection
threaded or flanged joint that mates a port to a pipe or to a piece of tubing
3.18
contacting seal
seal design in which the mating faces are not designed to intentionally create aerodynamic or
hydrodynamic forces to sustain a specific separation gap
NOTE Contacting seals can actually develop a full fluid film but this is not typical. Contacting seals do
not incorporate geometry, e.g. grooves, pads, face waviness, to ensure that the faces do not touch. The
amount of contact is generally very low and permits reliable operation with low leakage.
3.19
containment device
seal or bushing which is intended to manage leakage from the inner or outer seal and divert it to a
location determined by the user. See Annex F for further description
3.20
containment seal
special version of an outer seal used in Arrangement 2 and which normally operates in a vapour
(gas buffer or not buffer) but will seal the process fluid for a limited time in the event of an inner
seal failure. See 4.2
3.21
containment seal chamber
component or aggregate of components which form the the cavity into which the containment
seal is installed
3.22
containment seal chamber leakage collector
reservoir, connected by pipework to the containment seal chamber for the purpose of collecting
condensed leakage from the inner seal of an Arrangement 2.
3.23
crystallizing fluid
fluid which is in the process of forming solids or which may form solids due to dehydration or
chemical reaction
3.24
distributed flush system
arrangement of holes, passages, baffles, etc., designed to promote an even distribution of flush
fluid around the circumference of the seal faces.
NOTE these are normally required when piping plans provide flush into the seal chamber
12 © ISO 2009 – All rights reserved
DRAFT 2010
ISO/DIS 21049
3.25
drive collar
external part of the seal cartridge that transmits torque to the seal sleeve and prevents axial
movement of the seal sleeve relative to the shaft
3.26
dual mechanical seal
Arrangement 2 or Arrangement 3 seal of any type
3.27
dynamic sealing-pressure rating
highest pressure differential that the seal assembly can continuously withstand at the maximum
allowable temperature while the shaft is rotating
NOTE Thereafter, the seal retains its static sealing pressure rating.
3.28
dynamic secondary seal
secondary seal which is designed to slide or move relative to other components to allow axial
movement of the flexible element.
3.29
engineered seal
mechanical seal for applications with service conditions outside the operation scope of Type A, B
and C seals
NOTE Engineered seals are not required to meet any of the design or testing requirements of this
International Standard.
3.30
external circulating device
device located outside of the seal/buffer/barrier chamber to circulate seal chamber fluid through a
cooler or barrier/buffer fluid reservoir
3.31
face-to-back configuration
dual seal in which one mating ring is mounted between the two flexible elements and one flexible
element is mounted between the two mating rings and the pump process fluid is on the OD of the
inner seal and barrier of buffer fluid is on the ID of both the inner and outer seal.
3.32
face-to-face configuration
dual seal in which both of the mating rings are mounted between the flexible elements and the
pump process fluid is on the ID of the inner seal and barrier or buffer fluid is on the OD of both the
inner and outer seal
3.33
fixed bushing
cylindrical device with a close clearance to the shaft or sleeve which restricts flow between two
regions and which does not have a clearance on the outer diameter relative to the housing in
which it is mounted
DRAFT 2010
ISO/DIS 21049
3.34
fixed throttle bushing
one-piece cylindrical device that is fitted to the stationary part of the containment seal chamber
and has a radial clearance to a rotating component. It is used to help isolate one region from
another and assist in channelling liquid leakage to an exit port. The design is intended to maintain
a fixed radial clearance over the operating life of the seal. These devices have a low L/D ratio 0,2
or lower.
3.35
flashing
rapid change in fluid state from liquid to gas
NOTE In a dynamic seal, this can occur when frictional energy is added to the fluid as it passes
between the primary seal faces, or when fluid pressure is reduced below the fluid's vapour pressure
because of a pressure drop across the seal faces.
3.36
flashing hydrocarbon
flashing fluid
liquid hydrocarbon or other fluid with an absolute vapour pressure greater than 0,1 MPa [1 bar]
[14,7 psi] at the pumping temperature, or a fluid that will readily boil at ambient conditions
3.37
flexible element
combination of elements which accommodate axial movement of between rotating and stationary
parts
3.38
flexible graphite
exfoliated and recompressed graphite material used for static (secondary seal) gaskets in
mechanical seal design, from cryogenic to hot service
3.39
floating bushing
cylindrical device with a close clearance to the shaft or sleeve which restricts flow between two
regions and which has a clearance on the outer diameter relative to the housing in which it is
mounted to allow radial motion (“floating”) of the bushing should it come in contact with the
rotating shaft or sleeve
3.40
fluoroelastomer
FKM
saturated polymer in which hydrogen atoms have been replaced with fluorine. It is characterized
by excellent hydrocarbon and general chemical resistance.
3.41
flush, noun
fluid which is introduced into the seal chamber on the process fluid side in close proximity to the
seal faces and typically used for cooling and lubricating the seal faces and/or to keep them clean
14 © ISO 2009 – All rights reserved
DRAFT 2010
ISO/DIS 21049
3.42
gland plate
gland end plate
pressure retaining component(s) similar to a flange which connects the stationary assembly of a
mechanical seal to the seal chamber
NOTE A gland plate may consist of more than one pressure containing component for example the two
gland plates often used in a dual seal
3.43
hook sleeve
sleeve, with a step or hook at the product end, placed over the shaft to protect it from wear and
corrosion
NOTE The step is usually abutted against the impeller to hold it in place with a gasket between the
shaft and the step (hook).
3.44
inner seal
(Arrangement 2 and Arrangement 3) the seal closest to the pump impeller or process fluid
3.45
internally-mounted seal
seal configuration in which the seal is mounted within the boundaries of the seal chamber or
containment seal chamber or and gland plate
3.46
internal circulating device
device located in the seal buffer/barrier chamber to circulate fluid through a cooler or
barrier/buffer fluid reservoir
NOTE There are various designs to achieve radial or axial flow. The internal circulating device can be
integral with other seal parts or a separate part. (This device was formerly known as a “pumping ring”).
3.47
leakage concentration
measure of the concentration of a volatile organic compound or other regulated emission in the
environment immediately surrounding the seal
3.48
leakage rate
volume or mass of fluid passing through a seal in a given length of time
3.49
light h
...
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