ISO/FDIS 15783

ISO/TC 115/SC 1
Secretariat: BSI
Date: 2025-12-012026-xx
Seal-less rotodynamic pumps — Class II — Specification
Pompes rotodynamiques sans dispositif d'étanchéité d'arbre — Classe II — Spécifications
FDIS stage
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ii
Contents
Foreword . v
Introduction . vi
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 2
4 Design . 5
4.1 General . 5
4.2 Prime movers . 6
4.3 Critical speed, balancing and vibrations . 9
4.4 Pressure-containing parts . 10
4.5 Branches, nozzles and miscellaneous connections . 13
4.6 External forces and moments on flanges (inlet and outlet) . 14
4.7 Branch (nozzle) flanges . 14
4.8 Impellers . 14
4.9 Wear rings or equivalent components . 14
4.10 Running clearance . 14
4.11 Shafts . 15
4.12 Bearings . 15
4.13 Circulation flow . 16
4.14 Nameplates . 17
4.15 Direction of rotation . 17
4.16 Couplings for magnetic drive pumps . 17
4.17 Baseplate . 18
4.18 Monitoring . 19
5 Materials. 19
5.1 Selection of materials . 19
5.2 Material composition and quality . 20
5.3 Repairs . 20
6 Testing . 20
6.1 General . 20
6.2 Material tests . 20
6.3 Pump test and inspection . 20
7 Preparation for despatch . 23
7.1 Surface protection . 23
7.2 Securing of rotating parts for transport . 24
7.3 Openings . 24
7.4 Pipes and auxiliaries . 24
7.5 Identification . 24
8 Information for use . 24
Annex A (informative) Data sheet for magnetic drive pumps and canned motor pumps . 25
Annex B (informative) External forces and moments on flanges . 30
Annex C (informative) Enquiry, proposal and purchase order . 31
Annex D (informative) Documentation after purchase order . 32
Annex E (informative) Typical circulation piping plans and characteristics for canned motor
pumps and magnetic drive pumps . 33
iii
Annex F (informative) Internationally accepted materials for pump parts . 39
Annex G (informative) Checklist . 48
Bibliography . 50

iv
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.
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).
ISO draws attention to the possibility that the implementation of this document may involve the use of (a)
patent(s). ISO takes no position concerning the evidence, validity or applicability of any claimed patent rights
in respect thereof. As of the date of publication of this document, ISO [had/had not] received notice of (a)
patent(s) which may be required to implement this document. However, implementers are cautioned that this
may not represent the latest information, which may be obtained from the patent database available at
www.iso.org/patents. ISO shall not be held responsible for identifying any or all such patent rights.
Any trade name used in this document is information given for the convenience of users and does not
constitute an endorsement.
For an explanation of the voluntary nature of standards, the meaning of ISO specific terms and expressions
related to conformity assessment, as well as information about 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 Technical Committee ISO/TC 115, Pumps, Subcommittee SC 1, Dimensions
and technical specifications of pumps., in collaboration with the European Committee for Standardization
(CEN) Technical Committee CEN/TC 197, Pumps,in accordance with the Agreement on technical cooperation
between ISO and CEN (Vienna Agreement).
This second edition cancels and replaces the first edition (ISO 15783:2002), which has been technically
revised. It also incorporates the Amendment ISO 15783:2002/Amd.1:2008.
The main changes compared to the previous edition are as follows:
— — Normative references were extensively revised. Some references have been updated.
— — Liquid properties were added in 4.2.14.2.1.
— — Definition of rigid support added in Note of Table 1table 1.
— Annex F— Annex F was extensively revised. Hastelloy alloy was also added to Table F.1Table F1.
— 4.13.1— 4.13.1 and 4.13.34.13.3 paragraphs were added to Annex Ginformative Annex G;;
— — Bibliography was extensively revised.
Any feedback or questions on this document should be directed to the user’s national standards body. A
complete listing of these bodies can be found at www.iso.org/members.html.
v
Introduction
This International Standarddocument is the first of a series dealing with technical specifications for seal-less
pumps; they correspond to two classes of technical specifications, Classes I and II, of which Class I is the more
severe requirements.
Where a decision may be required by the purchaser, or agreement is required between the purchaser and
manufacturer/supplier, the relevant text is highlighted with • and is listed in Annex Gannex G.
vi
Seal-less rotodynamic pumps — Class II — Specification
1 Scope
This International Standarddocument specifies the requirements for seal-less rotodynamic pumps that are
driven with permanent magnet coupling (magnet drive pumps) or with canned motor, and which are mainly
used in chemical processes, water treatment and petrochemical industries. Their use can be dictated by space,
noise, environment or safety regulations.
Seal-less pumps are pumps where an inner rotor is completely contained in a pressure vessel holding the
pumped fluid. The pressure vessel or primary containment device is sealed by static seals such as gaskets or
O-rings.
Pumps will normally to recognized standard specifications (e.g. ISO 5199, explosion protection,
electromagnetic compatibility), except where special requirements are specified herein.
This International Standarddocument includes design features concerned with installation, maintenance and
operational safety of the pumps, and defines those items to be agreed upon between the purchaser and
manufacturer/supplier.
Where conformity to this International Standarddocument has been requested and calls for a specific design
feature, alternative designs maycan be offered providing that they satisfy the intent of this International
Standarddocument and they are described in detail. Pumps which do not conform with all requirements of
this International Standard maydocument can also be offered providing that the deviations are fully identified
and described.
Whenever documents include contradictory requirements, they are applied in the following sequence of
priority:
a) a) purchase order (or inquiry, if no order placed), see Annexes Cannexes C and DD;;
b) b) data sheet (see Annex Aannex A)) or technical sheet or specification;
c) c) this International Standarddocument;
d) d) other standards.
2 Normative references
The following documents are referred to in the text in such a way 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 76, Rolling bearings — Static load ratings
ISO 281, Rolling bearings — Dynamic load ratings and rating life
ISO 25178-601, Geometrical product specifications (GPS) — Surface texture: Areal — Part 601: Design and
characteristics of contact (stylus) instruments
Commented [eXtyles1]: The match came back with a
different title. The original title was: Geometrical Product
Specifications (GPS) — Surface texture: Profile method —
ISO 3744, Acoustics — Determination of sound power levels and sound energy levels of noise sources using sound
Nominal characteristics of contact (stylus) instruments
pressure — Engineering methods for an essentially free field over a reflecting plane
Commented [eXtyles2]: eXtyles Inline Standards Citation
Match reports that the normative reference "ISO 25178-601"
is not cited in the text.
ISO 3746, Acoustics — Determination of sound power levels and sound energy levels of noise sources using sound
pressure — Survey method using an enveloping measurement surface over a reflecting plane
ISO 5199, Technical specifications for centrifugal pumps — Class II
ISO 7005--1, Pipe flanges — Part 1: Steel flanges for industrial and general service piping systems
ISO 7005--2, Metallic flanges — Part 2: Cast iron flanges
ISO 7005--3, Metallic flanges — Part 3: Copper alloy and composite flanges
ISO 9906, Rotodynamic pumps — Hydraulic performance acceptance tests — Grades 1, 2 and 3
ISO 25178-601, Geometrical product specifications (GPS) — Surface texture: Areal — Part 601: Design and
characteristics of contact (stylus) instruments
IEC 60034-1, (all parts), Rotating electrical machines — Part 1: Rating and performance
EN 12162, Liquid pumps — Safety requirements — Procedure for hydrostatic testing
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
ISO and IEC maintain terminology databases for use in standardization at the following addresses:
— ISO Online browsing platform: available at https://www.iso.org/obp
— IEC Electropedia: available at https://www.electropedia.org/3.1
3.1
magnetic drive pump
MDP
pump in which the shaft power of the drive is transferred to the impeller of the pump by means of a permanent
magnetic field, which passes through a containment barrier (shell) to an inner rotor having permanent
magnets or an induction device
3.2 3.2
canned motor pump
CMP
pump in which the stator of an electric motor is separated from the rotor by a sealed containment barrier
(liner)
Note 1 to entry: The rotor runs in the liquid being pumped or in another liquid.
Note 2 to entry: The shaft power is transmitted by means of an electromagnetic field.
3.3 3.3
seal-less rotodynamic pump
pump design in which the impeller shaft also carries the rotor of either a canned induction motor or a
synchronous or an asynchronous magnetic drive
Note 1 to entry: The design does not use a dynamic shaft seal as a primary containment device. Static seals are the
means used for containing the fluid.
3.3.1 3.3.1
hydraulic end
end of the pump which transfers mechanical energy into the liquid being pumped
3.3.2 3.3.2
lubrication
flow necessary in a magnetic drive in the area between the inner magnet and the containment shell, or in a
canned motor between the rotor and the sleeve, for dissipation of the heat due to inherent Eddy current losses
in metallic containment shells and frictional heat generation from bearings, and for lubrication.
Note 1 to entry: Internal pump bearings are lubricated and cooled by the pumped fluid or an external, compatible
flushing fluid.
3.3.3 3.3.3
close coupled
coupling arrangement in which the motor is supplied with a flange adapter which mounts directly
onto the casing or body of the pump and in which the outer magnet ring is mounted onto the motor shaft
3.3.4 3.3.4
air gap
radial distance between the inner diameter (ID) of the outer magnet assembly and the outer diameter
(OD) of the containment shell
3.4 3.4
break-out torque
torque load applied to the drive shaft with the rotor locked at the point at which magnetic decoupling occurs
3.5 3.5
magnetic coupling
device which transmits torque through the use of magnet(s) attached to the drive and driven shafts
3.6 3.6
inner magnet ring
rows of magnets operating within the containment shell, driven by the outer magnet ring (3.7)
Note 1 to entry: The inner magnet ring is mounted on the same rotating element as the pump impeller.
3.7 3.7
outer magnet ring
rows of permanent magnets securely fixed to a carrier, evenly spaced to provide a uniform magnetic field
Note 1 to entry: outer magnet ring, while rotating, transmits power through a containment shell, driving the inner
magnet ring or torque ring.
3.8 3.8
Eddy currents
electrical currents generated in a conductive material when strong magnetic fields are rotated around it
3.8.1
eddy current drive
Commented [eXtyles3]: The term "eddy current drive" is
used only in terms and definitions section
asynchronous magnetic coupling consisting of a permanent outer magnet ring and an inner torque ring
containing a network of conductive rods supported on a mild steel core
Note 1 to entry: The rotating outer magnet ring generates eddy currents in the copper rods which convert the core to an
electromagnet. The electromagnet follows the rotating outer magnet ring but at a slightly slower speed due to slip.
3.8.53.8.1 3.8.2
Eddy current loss
power loss resulting from Eddy currents (3.8)
Note 1 to entry: The energy in these Eddy currents is normally dissipated as heat due to the electrical resistance of the
material.
3.8.3
torque ring
Commented [eXtyles4]: The term "torque ring" is used
only in terms and definitions section
laminations and conductors mounted on the rotor in which electric currents are induced in an eddy current
drive
3.8.93.8.2 3.8.4
decouple
failure of a synchronous magnetic coupling (3.5) to rotate synchronously, or the stall condition of an eddy
current drive
3.9 3.9
Containment
3.9.1 3.9.1
sheath
thin-walled hermetically sealed enclosure fitted to the inner rotor enclosing the inner magnet ring (3.6) (MDP)
or rotor laminations (CMP)
Note 1 to entry: See Figures 1Figures 1 and 22.
3.9.2 3.9.2
shell
hermetically sealed enclosure fitted within the total-gap between the inner magnet ring (3.6) and the outer
magnet ring (3.7rings) of an MDP and which provides for the primary containment of the pumped liquid
Note 1 to entry: See Figure 2Figure 2.
3.9.3 3.9.3
liner
hermetically sealed enclosure fitted to the ID of the stator assembly of a CMP and providing for the primary
containment of the pumped liquid
Note 1 to entry: See Figure 1Figure 1.
3.9.4 3.9.4
secondary containment
backup pressure-containing system using static seals only to contain leakage in the event of failure of the
primary containment by shell (3.9.2(3.9.2)) or by liner (3.9.3(3.9.3),), and including provisions to indicate a
failure of the containment shell or liner
3.9.5 3.9.5
drive shaft
outer shaft of the magnetic drive coupling
3.9.6 3.9.6
secondary control
minimization of release of pumped liquid in the event of failure of the containment shell (3.9.2(3.9.2)) or stator
liner
15783_ed2fig1.EPS
Key
1 hydraulic end
2 bearing
3 liner
4 terminal box
5 stator assembly
6 rotor sheath
7 rotor
Figure 1 — Example of a canned motor pump (CMP)
15783_ed2fig2.EPS
Key
1 hydraulic end
2 bearing
3 shell
4 bearing housing
5 rolling bearing
6 coupling
7 prime mover
8 baseplate
9 sheath: inner magnet ring
10 outer magnet ring
Figure 2 — Example of a magnetic drive pump (MDP)
274 Design
27.14.1 General
27.1.14.1.1 Characteristic curve
The characteristic curve shall indicate the permitted operating range of the pump. Pumps should have a stable
characteristic curve. In addition, the characteristic curves for the smallest and largest impeller diameters shall
also be shown.
Minimum and maximum continuous stable flows at which the pump can operate without exceeding the noise,
vibration and temperature limits imposed by this International Standard shall clearly be stated by the
manufacturer/supplier.
27.1.24.1.2 Net Positive Suction Head (NPSH)
•The NPSH required (NPSHR) shall be based on cold water testing as determined by testing in accordance
with ISO 9906 unless otherwise agreed.
The manufacturer/supplier shall make available a typical curve as a function of flow for water. NPSHR curves
shall be based upon a head drop of 3 % (NPSH3).
Correction factors for hydrocarbons shall not be applied to the NPSHR curves.
Pumps shall be selected such that the minimum NPSH available (NPSHA) in the installation exceeds the NPSHR
of the pump by at least the specified safety margin. This safety margin shall be not less than 0,5 m, but the
manufacturer/supplier may specify a significantly higher margin depending on factors including the
following:
— — size, type, specific speed, hydraulic geometry or design of the pump;
— — operating speed or inlet velocity;
— — the pumped liquid and temperature;
— — the cavitation erosion resistance of the construction materials.
27.1.34.1.3 Outdoor installation
The pumps shall be suitable for outdoor installation under normal ambient conditions.
•Local regulations or extraordinary ambient conditions, such as high or low temperatures, corrosive
environment, sandstorms, for which the pump is required to be suitable should be specified by the purchaser.
27.24.2 Prime movers
27.2.14.2.1 General
The following shall be considered when determining the power/speed requirements of the pump.
a) a) The application and method of operation of the pump. For example, in an installation intended
for parallel operation, the possible performance range with only one pump in operation, taking into
account the system characteristic.
b) b) The position of the operating point on the pump characteristic curve.
c) c) The circulation flow for lubrication of bearings and removal of heat losses (especially for
pumps with low rates of flow).
d) d) Properties of the pumped liquid (viscosity, solids content, density, specific heat, vapour
pressure).
e) e) Power loss, including slip loss through transmission (only magnet drive pumps).
f) f) Atmospheric conditions at the pump site.
g) g) Starting method of the pump:
— — if a pump (e.g., a stand-by pump) is started automatically then consideration shall be given to
whether the pump may start against a closed valve, or whether the pump may start against an open
valve or be pumping into an empty pipeline; i.e. operates within a pumping system in which the pump
pressure is provided only for pipeline friction losses.
h) h) For variable speed arrangements the minimum continuous speed shall be indicated by the
manufacturer/ supplier to ensure proper cooling and lubrication of the bearings.
Prime movers required as drivers for seal-less pumps covered by this International Standard shall have power
output ratings at least equal to the percentage of rated power input given in Figure 1Figure 3,, this value never
being less than 1 kW.
Where it appears that this will lead to unnecessary oversizing of the driver, an alternative proposal shall be
submitted for the purchaser's approval.
15783_ed2fig3.EPS
Key
X pump power input at rated conditions, kW
Y prime mover output, percentage of pump power input at rated conditions, %
Figure 3 1 — Prime mover output, percentage of pump power input at rated conditions
27.2.24.2.2 Magnetic drive pumps
When determining the permanent magnetic drive to be used, the following points shall be taken into
consideration in addition to the points a) to h) listed under 4.2.14.2.1.
a) a) The magnetic drive shall be selected for the allowed operating range with the selected impeller
diameter at operating temperature and taking into consideration the characteristics of the liquid to be
pumped.
•If the density of the liquid of the normal operation is below 1 000 kg/m special agreements between the
manufacturer/supplier and purchaser for testing and cleaning shall be made.
b) b) Heat generated by Eddy current losses, power losses in the shell, power losses in the bearings
and power losses due to liquid circulation shall be removed by pumped liquid or by supply of external
cooling fluid.
c) c) The magnetic material temperature shall be maintained at or below rated values for the
material used. Magnetic materials should not be subject to irreversible losses.
d) d) The irreversible magnetic losses at operating temperatures of the magnetic drive shall be
considered.
Fluids containing magnetically attracted particles should be avoided unless such particles can be effectively
removed.
Special arrangements may be provided to avoid formation of ice in air gaps when pumping cold liquids.
The magnetic drive shall be designed in such a manner that start-up will not cause the magnet assemblies to
decouple, see Figure 2.
Key
1 hydraulic end
2 bearing
3 shell
4 bearing housing
5 rolling bearing
6 coupling
7 prime mover
8 baseplate
9 sheath: inner magnet ring
10 outer magnet ring
Figure 2 — Example of a magnetic drive pump (MDP)
27.2.34.2.3 Canned motor pumps
Canned motors are generally cooled by circulation of pumped liquid or by the use of coolant liquid to remove
heat generated by the containment liner, Eddy current losses, motor electrical losses and mechanical losses.
Stator winding temperatures shall be maintained at or below values established for the grade of insulation
used, see Figure 3.
When rating a canned motor, the conditions listed below shall be taken into consideration in addition to points
a) to h) listed under 4.2.14.2.1::
— — power losses within the canned rotor;
— — power losses in the bearings;
— — power losses due to liquid circulation;
— — explosion protection requirements.
Manufacturers/suppliers shall specify external cooling requirements when required.
Stand-by units may require special arrangements for flushing and/or heating to prevent the settling out of
solids, or the formation of ice, or solidification or too low viscosity of the liquid to be pumped.
•The details of such arrangements should be agreed upon between the purchaser and manufacturer/supplier.

Key
1 hydraulic end
2 bearing
3 liner
4 terminal box
5 stator assembly
6 rotor sheath
7 rotor
Figure 3 — Example of a canned motor pump (CMP)
27.34.3 Critical speed, balancing and vibrations
27.3.14.3.1 Critical speed
The critical speed shall be calculated with liquid.
•For some pump types (e.g., vertical line shaft and horizontal multistage), the first critical speed may be below
the operating speed when agreed between the purchaser and manufacturer/supplier.
Particular attention shall be paid to the critical speed when the pump is to be driven at variable speed.
27.3.24.3.2 Balancing and vibration
27.3.2.14.3.2.1 General
All major rotating components shall be balanced.
27.3.2.24.3.2.2 Horizontal pumps
Unfiltered vibration shall not exceed the vibration severity limits as given in Table 1Table 1 when measured
1)
on the manufacturer's/supplier's test facilities. . These values are measured radially at the bearing housing
at a single operating point at rated speed (±5 %) and rated flow (±5 %) when operating without cavitation.

1)
For in situ acceptance limits refer to ISO 20816-3.
The manufacturer/supplier shall determine the grade of balancing required in order to achieve acceptable
vibration levels within the limits specified in this International Standard.
NOTE This can normally be achieved by balancing in accordance with a minimum of class G6.3 of ISO 21940-11
Table 1 — Maximum allowable unfiltered vibration values Values in millimetres per second (mm/s)
Pump type and criterion
Pump arrangement
Canned motor pump Magnetic drive pump
Pump with rigid support
2,3 3,0
centreline height ≤ 225 mm
Pump with rigid support
3,0 4,5
centreline height > 225 mm
Pump with flexible support 3,0 4,5
NOTE 1 The values of vibration velocity filtered for rotating frequency and blade passing
frequency can be expected to be lower than given in the table.
NOTE 2 A rigid support is one where the lowest natural frequency of the combined machine
and support system in the direction of measurement is at least 25 % higher than the rotational
frequency. Any other support is considered flexible.
27.3.2.34.3.2.3 Vertical pumps
Vibration readings shall be taken on the top flange of the driver mounting on vertical pumps with rigid
couplings and near to the top pump bearing on vertical pumps with flexible couplings.
Vibration limits for both rolling and sleeve bearing pumps shall not exceed the vibration severity limits as
given in Table 1Table 1 during shop test at rated speed (±5 %) and rated flow (±5 %) operating without
2)
cavitation. .
27.44.4 Pressure-containing parts
27.4.14.4.1 Primary containment
Containment of the pumped liquid shall be by means able to withstand the stresses derived from the maximum
allowable working pressure and any dynamic effects of operation. The wetted materials shall be compatible
with each other and the pumped liquid, and shall be dimensioned to give an adequate working life.
It is recognized that several effective methods are suitable for the design of pressure-containing parts. These
may be based upon recognized national codes or upon other proven methods. To satisfy the acceptance
criteria, each design method shall
— — be a written procedure,
— — recognize limits of material stresses,
— — incorporate a checking stage, and
— — have been proven empirically or experimentally.

2)
For in situ acceptance limits refer to ISO 20816-3.

27.4.24.4.2 Secondary containment
Where containment of any leakage is considered to be desirable, the pump shall be provided with a secondary
containment.
The secondary containment shall be designed to allow installation of a sensor by the purchaser to indicate
change in status and either to shut-down the pump or to warn that attention and rectification is required. The
secondary containment shall sustain this condition when exposed to the pumped liquid for a minimum of 48 h.
It shall be capable of containment under the maximum allowable working pressure, temperature and any
dynamic effects from operation.
27.4.34.4.3 Secondary control
Where the liquid is less hazardous, but uncontrolled leakage is unacceptable for environmental or personal
comfort reasons, the pump shall be provided with a means to control leakage from the primary containment.
Secondary control shall provide a safe means to collect leakage from the primary containment and present it
in a manner that will allow its safe disposal. The manufacturer/supplier shall define the maximum allowable
working pressure and provide a disposal connection capable of discharging 20 % of the pump flow rate
without this pressure being exceeded.
27.4.44.4.4 Pressure-temperature rating
The maximum allowable working pressure of the pump at the most severe operating conditions shall be
clearly stated by the manufacturer/supplier. In no case shall the maximum allowable working pressure of the
pump exceed the flange rating.
The basic design pressure of the pump shall be at least a gauge pressure of 1,6 MPa (16 bar) at 20 °C when the
tensile requirements of the material permit.
In the case of materials whose strength does not permit the basic design pressure for 1,6 MPa (16 bar) rating
at 20 °C, or where the pump is to be used at temperatures other than 20 °C, the pressure rating shall be
adjusted according to the stress-temperature characteristics of the material and shall be clearly stated by the
manufacturer/supplier.
The containment shell/liner shall be resistant to a pressure of 10 kPa (0,1 bar) absolute and designed for a
gauge pressure of 1,6 MPa (16 bar) at 250 °C in the case of metallic materials, and to a vacuum of 50 kPa
(0,5 bar) absolute and a gauge pressure of 1,6 MPa (16 bar) at 20 °C in the case of non-metallic materials.
27.4.54.4.5 Wall thickness
27.4.5.14.4.5.1 General
Pressure-containing parts, including containment shell/liner, shall be dimensioned so that they are capable of
withstanding the allowable working pressure at working temperature without deformation which interferes
with the safe operation of the pump. The test pressure shall not cause any permanent deformation in
accordance with 6.3.16.3.1. The casing shall also be suitable for the hydrostatic test pressure (see 6.3.16.3.1))
at ambient temperature.
•The corrosion allowance for all pressure-containing parts, excluding the shell/liner, shall be agreed upon
between the purchaser and manufacturer/supplier by consideration of corrosion rates for the liquids and
materials involved.
27.4.5.24.4.5.2 Magnetic drive pumps
The containment shell shall be made of corrosion-resistant material of not less than 1 mm thickness, which
shall include an allowance for any corrosion loss, as agreed upon by the purchaser.
27.4.5.34.4.5.3 Canned motor pumps
The minimum wall thickness of the liner shall be 0,3 mm and be of corrosion-resistant material.
27.4.64.4.6 Materials
The materials used for pressure-containing parts shall depend on the liquid pumped and the application of
the pump (see Clause 5clause 5).).
27.4.74.4.7 Mechanical features
27.4.7.14.4.7.1 Dismantling
The pump shall preferably be designed in back-pull-out construction in order to permit removal of the
impeller, shaft, magnetic drive and bearing assembly without disturbing the inlet and outlet flange
connections. Provision shall be made for easy separation of components (e.g.,. jackscrews).
27.4.7.24.4.7.2 Jackscrews
When jackscrews are supplied as a means of separating contacting faces, the mating face shall be counter-
bored to receive the jackscrews where damage to the surface offers a possibility of a leaking joint or a poor fit.
Socket head screws shall be avoided, if possible.
27.4.7.34.4.7.3 Heating and cooling jackets
Jackets for heating and cooling shall be provided where required.
Heating jackets shall be designed for an operating pressure of at least 600 kPa (6 bar) at 200 °C (steam) or
600 kPa (6 bar) at 350 °C (heat transfer fluid). Cooling jackets shall be designed for a minimum operating
pressure of 600 kPa (6 bar) at 170 °C.
The manufacturer/supplier shall specify when external heating or cooling is required. Annex EAnnex E gives
typical systems.
27.4.7.44.4.7.4 Pressure-containment gaskets
Pressure-containment gaskets shall be of a design suitable for the allowable working conditions and for
hydrostatic test conditions. They shall be confined to the atmospheric side to prevent blow-out.
27.4.7.54.4.7.5 External bolting
Bolts or studs connecting pressure-containing parts, such as pump casing and cover including magnetic
coupling or canned motor, shall have a minimum size of 12 mm.
NOTE If owing to space limitations, the use of M 12 bolts or studs is impractibleimpracticable, smaller bolts or studs
might beare permitted.
The bolting selected (property class) shall be adequate for the maximum allowable pressure using the normal
tightening procedures. If at some point it is necessary to use fasteners of special quality, interchangeable
fasteners for other joints shall be of the same quality.
27.4.7.64.4.7.6 Casing support for high temperatures
For applications of magnetic drive pumps other than of close coupled construction above a working
temperature of 350 °C, centreinecentreline support of the casing shall be provided.
27.54.5 Branches, nozzles and miscellaneous connections
27.5.14.5.1 Extent
This subclause is concerned with all liquid connections to the pump whether for operation or maintenance.
27.5.24.5.2 Inlet and outlet branches
Inlet and outlet branches shall be flanged and in the case of single-stage centrifugal pumps shall be designed
for the same nominal pressure, unless the pump manufacturer/supplier states that this is not so and
emphasizes the requirements for pressure relief.
27.5.34.5.3 Venting and draining
27.5.3.14.5.3.1 4.5.3.1 The entire unit, including casing, drive section and
manufacturer-supplied piping shall be self-venting or furnished with vent connections.
27.5.3.24.5.3.2 4.5.3.2 All areas containing pumped liquid, including vendor-supplied
piping, shall be drainable.
•The purchaser shall advise when he requires additional flushing connections to allow the unit to be flushed
prior to disassembly.
NOTE Connections for venting and draining are normally not drilled.
•The inquiry and/or order should state if connections for venting and draining are required to be drilled.
•For multistage pumps, draining devices should be agreed between the purchaser and manufacturer/supplier.
27.5.44.5.4 Pressure gauge connections
The connection of pressure gauges at the inlet and outlet branches shall be possible.
NOTE Pressure gauge connections are normally not drilled.
•The inquiry and/or order should state if pressure gauge connections are required to be drilled.
27.5.54.5.5 Closures
The material for the closures (plugs, blanks, blind flanges, etc.) shall be appropriate to the pumped liquid.
Attention shall be paid to the suitability of the material combinations for corrosion resistance and to minimize
the risk of seizure or galling of screw threads.
27.5.64.5.6 Auxiliary pipe connections
All auxiliary pipe connections shall be of adequate material, size and thickness for the intended duty.
The inside diameter shall be at least 8 mm and the wall thickness 1 mm. Greater diameters and wall
thicknesses are preferred.
Auxiliary piping shall be provided with detachable joints to permit easy dismantling.
•The type of connections shall be subject to agreement.
For connections ≥ DN 25, flanged connections shall be used and have a rating compatible with the service
pressure.
27.5.74.5.7 Connection identification
All connections for auxiliary piping shall be identified in the installation drawing in accordance with their duty
and function. It is recommended that this identification also be applied on the pump for use during installation.
27.64.6 External forces and moments on flanges (inlet and outlet)
•The method given in ISO 5199 shall be used unless another method is agreed between the purchaser and
manufacturer/supplier.
The purchaser is responsible for calculating the forces and moments exerted by the piping on the pump. The
manufacturer/supplier shall verify that these loads are permissible for the pump under consideration.
•If the loads are higher than permissible, the solution to the problem shall be agreed between the purchaser
and manufacturer/supplier.
27.74.7 Branch (nozzle) flanges
The flange envelope shall be of a size to enable flanges in accordance with the appropriate part of ISO 7005
(series) to be provided. If the pump manufacturer's/supplier's standard pattern entails a flange thickness
greater than that of the rating specified, the heavier flange can be supplied but it shall be faced and drilled as
specified. Good seating of the bolt head and/or nut on the back face of the cast flanges shall be ensured. Bolt
holes shall straddle the centreline.
27.84.8 Impellers
27.8.14.8.1 Impeller design
Impellers of closed, semi-open or open designs may be selected according to the application.
Cast or welded impellers shall consist of one piece, excluding wear rings.
Impellers fabricated by other means are permissible in special cases, i.e.,. for small impeller outlet widths or
special materials.
•This however requires agreement with the purchaser.
27.8.24.8.2 Securing of impellers
Impellers shall be securely fixed against circumferential and axial movement when rotating in the intended
direction. Impellers used in CMP units shall also be securely fixed against reverse rotation.
27.94.9 Wear rings or equivalent components
Where wear rings are fitted, they shall be renewable and securely locked to
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