ISO/FDIS 24826

• Status: Not Published
• ICS: 75.180.10 - Exploratory, drilling and extraction equipment
• Technical Committee: ISO/TC 67/SC 4 - Drilling and production equipment
• Drafting Committee: ISO/TC 67/SC 4/WG 1 - Drilling equipment
• Current Stage: 5020 - FDIS ballot initiated: 2 months. Proof sent to secretariat
• Start Date: 30-Sep-2026
• Completion Date: 30-Sep-2026

Overview

ISO/FDIS 24826:2026 is an international standard developed by ISO/TC 67/SC 4 that addresses requirements for mud pumps used in the oil and gas industries, including operations focused on lower carbon energy solutions. The standard is relevant for both drilling and production activities and provides comprehensive specifications covering the design, verification, quality control, installation, operation, and maintenance of single-action piston mud pumps. These pumps play a vital role in circulating drilling fluids, ensuring safe and efficient drilling processes, and supporting both conventional and lower carbon energy applications.

Key Topics

• Design and Verification: The standard provides detailed criteria for the design of mud pumps, emphasizing safety, reliability, and conformity with operational requirements. Design verification processes, including finite element analysis (FEA) and validation against performance requirements, are critical components.
• Technical Specifications: Key parameters such as rated input power, maximum pump pressure, displacement, liner size, materials, and component tolerances are defined to ensure consistency and performance.
• Quality Control and Marking: There are stringent requirements for material traceability, inspection, testing, and product marking to ensure quality and compliance with international regulations.
• Installation, Operation, and Maintenance: Guidelines for proper storage, packing, transportation, installation, and regular maintenance are included to maximize operational life and safety.
• Health, Safety, and Environmental (HSE) Requirements: Provisions for safety covers, protection for exposed parts, and clear safety marking enhance operator safety and facilitate best practices in the field.
• Documentation: Comprehensive documentation, including inspection reports, quality records, and technical specifications, must be maintained and provided.

Applications

ISO/FDIS 24826 is applicable to a wide range of operations in oil, gas, and lower-carbon energy projects where drilling, production, and injection processes require reliable and safe mud pumping equipment. Typical practical applications include:

• Onshore and Offshore Drilling: Specification and procurement of mud pumps for exploratory and production wells in various geographies.
• Workover Operations: Supporting intervention tasks where mud pumps are critical to maintaining downhole pressure.
• Lower Carbon Energy Projects: Applicability in geothermal and carbon capture and storage (CCS) projects that use similar drilling technologies, enhancing compatibility with modern energy transition strategies.
• Equipment Manufacturing and Procurement: Providing a unified reference for suppliers, OEMs, and purchasers to ensure that mud pumps deliver consistent performance, comply with safety standards, and are compatible globally.
• Maintenance and Operations: Facilitating consistent maintenance regimes and troubleshooting, reducing downtime and equipment failure.

By adopting ISO/FDIS 24826, organizations can assure stakeholders of adherence to internationally recognized practices, reduce operational risks, and streamline procurement and maintenance processes.

Related Standards

ISO/FDIS 24826 makes reference to several other important international standards to ensure comprehensive coverage and facilitate interoperability, including:

• ISO 148-1: Charpy impact testing for metallic materials
• ISO 492 and ISO 5753-1: Tolerances and internal clearances for rolling bearings
• ISO 6336 Series: Gear load capacity calculations for spur and helical gears
• ISO 9934 Series: Magnetic particle testing principles and equipment
• ISO 10423: Drilling and production equipment for wellhead and tree applications
• ISO 14693: Drilling and well-servicing equipment

Organizations procuring or manufacturing mud pumps for use in oil and gas, geothermal energy, or CCS projects should ensure compliance not only with ISO/FDIS 24826 but also related standards for materials, testing, and safety.

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Keywords: ISO 24826, mud pumps, oil and gas industry, drilling equipment standard, lower carbon energy, quality control, safety requirements, equipment maintenance, technical specification, international standard, API compliance, drilling rig components

FINAL DRAFT
International
Standard
ISO/TC 67/SC 4
Oil and gas industries including
Secretariat: ANSI
lower carbon energy — Drilling,
Voting begins on:
production and injection equipment
2026-09-30
— Mud pumps
Voting terminates on:
2026-11-25
Industries du pétrole et du gaz, y compris les énergies à faible
teneur en carbone — Équipements de forage, de production et
d'injection — Pompes à boue
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
BEING ACCEPTABLE FOR INDUSTRIAL, TECHNO­
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.
Reference number
FINAL DRAFT
International
Standard
ISO/TC 67/SC 4
Oil and gas industries including
Secretariat: ANSI
lower carbon energy — Drilling,
Voting begins on:
production and injection equipment
— Mud pumps
Voting terminates on:
Industries du pétrole et du gaz, y compris les énergies à faible
teneur en carbone — Équipements de forage, de production et
d'injection — Pompes à boue
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.
© ISO 2026
IN ADDITION TO THEIR EVALUATION AS
All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication may
BEING ACCEPTABLE FOR INDUSTRIAL, TECHNO­
LOGICAL, COMMERCIAL AND USER PURPOSES, DRAFT
be reproduced or utilized otherwise in any form or by any means, electronic or mechanical, including photocopying, or posting on
INTERNATIONAL STANDARDS MAY ON OCCASION HAVE
the internet or an intranet, without prior written permission. Permission can be requested from either ISO at the address below
TO BE CONSIDERED IN THE LIGHT OF THEIR POTENTIAL
or ISO’s member body in the country of the requester.
TO BECOME STAN DARDS TO WHICH REFERENCE MAY BE
MADE IN NATIONAL REGULATIONS.
ISO copyright office
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Phone: [phone]
Email: [e-mail]
Website: www.iso.org
Published in Switzerland Reference number
ii
Contents Page
Foreword .v
Introduction .vi
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 2
4 Symbols and abbreviations . 3
4.1 Symbols .3
4.2 Abbreviated terms .3
5 Functional specification . 3
5.1 General .3
5.2 Mud pumps type description .4
5.3 Functional requirements . .4
5.3.1 General .4
5.3.2 Necessary functional parameters .4
5.3.3 Other parameters or requirements .4
5.4 User/purchaser selections .4
6 Technical specification . 5
6.1 General .5
6.2 Design criteria .5
6.2.1 General .5
6.2.2 Design conditions .5
6.2.3 Series and main parameters .5
6.2.4 Technical parameters and rating values .6
6.2.5 Scope of the primary load-carrying components and expendable items .7
6.2.6 Materials .7
6.2.7 Design requirements .8
6.2.8 Design Verification . 15
6.2.9 Design validation .16
6.2.10 Design document .16
7 Supplier/manufacturer requirements .16
7.1 Test and inspection .16
7.1.1 Hydrostatic test .16
7.1.2 Factory acceptance test .17
7.1.3 Type test . .18
7.1.4 Records . 20
7.2 Marking . 20
7.2.1 Requirements of marking . . 20
7.2.2 Method of marking . 20
7.2.3 Nameplate . .21
7.3 Quality control .21
7.3.1 General .21
7.3.2 Visual examination .21
7.3.3 Non-destructive testing (NDT) .21
7.3.4 Quality inspection . 22
7.4 Documentation . 23
7.4.1 Record retention . 23
7.4.2 Documentation to be kept by the supplier/manufacturer . 23
7.4.3 Documentation to be delivered with the equipment . 23
8 Storage, packing and transportation .24
8.1 General .24
8.2 Storage .24
8.3 Packing and transportation .24

iii
9 Installation, operation, and maintenance .25
9.1 Basic requirements . 25
9.2 Installation . 25
9.3 Preparation before operation . 25
9.4 Operation principle of mud pump . 26
9.5 Trouble symptoms of mud pump . 26
Annex A (informative) Nomenclature of principal parts of piston mud pump .28
Annex B (informative) The pinion shaft dimensions of mud pump .35
Annex C (informative) Example of marks .36
Annex D (informative) Configuration of mud pump .37
Bibliography .39

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 document 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 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 67, Oil and gas industries including lower carbon
energy, Subcommittee SC 4, Drilling, production and injection equipment.
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 document has been prepared by users/purchasers and suppliers/manufacturers of mud pumps
and is intended for use in the petroleum and natural gas industries worldwide. This document provides
requirements and information to both parties in the selection, manufacturing, testing and use of mud pumps.
Furthermore, this document addresses supplier specifications and provides the components composition
diagram of the mud pump (see Annex A).

vi
FINAL DRAFT International Standard ISO/FDIS 24826:2026(en)
Oil and gas industries including lower carbon energy —
Drilling, production and injection equipment — Mud pumps
1 Scope
This document provides the requirements for the design, design verification and confirmation, quality
control, product marking, storage, packaging and transportation, installation, operation and maintenance of
single-action piston mud pumps utilized in the petroleum and natural gas industries.
This document applies to the components of mud pumps, including the power end and fluid end components.
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 148-1, Metallic materials — Charpy pendulum impact test — Part 1: Test method
ISO 492, Rolling bearings — Radial bearings — Geometrical product specifications (GPS) and tolerance values
ISO 780, Packaging — Distribution packaging — Graphical symbols for handling and storage of packages
ISO 4986, Steel and iron castings — Magnetic particle testing
ISO 5753-1, Rolling bearings — Internal clearance — Part 1: Radial internal clearance for radial bearings
ISO 6336-1, Calculation of load capacity of spur and helical gears — Part 1: Basic principles, introduction and
general influence factors
ISO 6336-2, Calculation of load capacity of spur and helical gears — Part 2: Calculation of surface durability
(pitting)
ISO 6336-3, Calculation of load capacity of spur and helical gears — Part 3: Calculation of tooth bending strength
ISO 6336-5, Calculation of load capacity of spur and helical gears — Part 5: Strength and quality of materials
ISO 9934-1, Non-destructive testing — Magnetic particle testing — Part 1: General principles
ISO 9934-2, Non-destructive testing — Magnetic particle testing — Part 2: Detection media
ISO 9934-3, Non-destructive testing — Magnetic particle testing — Part 3: Equipment
ISO 10423, Petroleum and natural gas industries — Drilling and production equipment — Wellhead and tree
equipment
1)
ISO 14693:2003 , Petroleum and natural gas industries — Drilling and well-servicing equipment
MSS SP-55, Quality Standard for Steel Castings for Valves, Flanges and Fittings and Other Piping Components —
Visual Method for Evaluation of Surface Irregularities
1) Withdrawn.
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
mud pump
key equipment used to pump drilling fluid to downhole during the process of drilling or workover
Note 1 to entry: Generally, it is the positive displacement reciprocating pump.
3.2
fluid cylinder
shell in which valve assembly, liner, suction manifold and discharge manifold are installed and through
which high pressure fluid is passed
3.3
valve pot
inside the cylinder, where the valve assembly and valve spring are installed
3.4
discharge pulsation dampener
airtight container with sufficient air/nitrogen mounted at the discharge manifold of pump
3.5
discharge relief valve
relief valve is set to ensure the pump discharge pressure does not exceed a certain allowable value
3.6
stroke
moving distance of piston from the front starting point to the back-end point during the operation of mud
pump
3.7
pump speed
number of reciprocating motions per minute for a piston
3.8
rated pressure
maximum pressure allowed by a mud pump at a specified size of liner
Note 1 to entry: The rated pressure of the mud pump varies with the liner size.
3.9
maximum pump pressure
maximum working pressure allowed by a mud pump at the minimum size of liner
Note 1 to entry: The maximum pump pressure of a mud pump has only one value.
3.10
discharge pressure nonuniformity
ratio of the maximum fluctuating pressure to the average pressure in the mud pump discharge manifold
3.11
primary pressure-containing components of fluid end
components of the fluid end through which the discharge pressure is carried, except expendable parts and
seals
3.12
consumable parts
parts are designed to be used up, depleted, or worn out during the normal operation of mud pump and needs
to be regularly replaced or replenished
3.13
maintenance
measures which are taken to maintain the service performance of the equipment
Note 1 to entry: Including inspection, adjustment, cleaning, lubrication, testing, consumable parts replacement, etc.
4 Symbols and abbreviations
4.1 Symbols
rated pressure under a certain liner bore
P
η overall efficiency of the pump
rated input power
N
rated flow rate under a certain liner bore
Q
Q theoretical flow rate of the pump at a certain liner bore
i number of liners or pistons
F the area corresponding to a certain liner bore
S stroke
n pump speed
D liner bore
rated flow rate under each liner
Q
rated pump impulse under each liner
n
4.2 Abbreviated terms
FEA finite element analysis
NDT non-destructive test
PQR procedure qualification record
OEM original equipment manufacturer
5 Functional specification
5.1 General
The user/purchaser shall prepare a functional specification to order products that conform to this document,
and to specify the requirements and operating conditions of mud pump. The user/purchaser shall specify
the units of measurement for the data provided. This information is used by the supplier/manufacturer to
recommend the mud pumps for application conditions.

5.2 Mud pumps type description
The user/purchaser shall order the triplex or quintuplex mud pump according to the production
requirements.
5.3 Functional requirements
5.3.1 General
The user/purchaser should clarify the known and expected application parameters and requirements.
5.3.2 Necessary functional parameters
The user/buyer shall specify the following application parameters:
— rated power;
— maximum displacement;
— maximum pump pressure;
— ambient operating temperature.
5.3.3 Other parameters or requirements
The user/buyer should specify the following parameters or requirements:
— mud density and pH value;
— shipping requirements;
— requirements for delivery documents;
— testing and acceptance requirements;
— others.
5.4 User/purchaser selections
The user/purchaser selections shall be specified as follows:
— the connecting thread of metric pumps is metric thread, and the liner piston is also metric thread;
— the specifications of the liner and piston assembled inside the mud pump before the mud pumps delivery;
— the internal gear lubrication oil pump or external electric lubrication oil pump shall be determined. If an
external electric lubrication oil pump is used, the voltage, frequency, and explosion-proof requirements
of the motor;
— mechanical spray pump or electric spray pump shall be determined. If an electric spray pump is used, the
voltage, frequency, and explosion-proof requirements of the motor;
— the forged pulsation dampener or cast pulsation dampener;
— the shear pin relief valve or the spring reset relief valve.

6 Technical specification
6.1 General
The supplier/manufacturer shall prepare a technical specification to respond to the requirements in the
functional specification, or to identify in detail the differences from the requirements in the functional
specification.
6.2 Design criteria
6.2.1 General
The design of the mud pump shall meet its intended applications and reliability requirements. Each
component of the mud pump shall be capable of safely transmitting the specified loads and power. The
design of the mud pump shall ensure the safe operation of the equipment. The supplier/manufacturer shall
demonstrate the product conformity to the design and performance requirements specified in 6.2.8 and
6.2.9.
6.2.2 Design conditions
The following design conditions shall apply:
— the mud pump is designed to operate under continuously working conditions;
— the series and main technical parameters of the mud pump should conform to the provisions of 6.2.3;
— a low-temperature impact test at -20 °C shall be required for the materials of the primary pressure-
containing components of fluid end of the mud pump. The design load capacity of the fluid end is the
maximum discharge pressure, and the design load capacity of the power end is the maximum load of the
piston rod under the rated pressure corresponding to the minimum liner bore;
— the design load capacity of the fluid end is the maximum discharge pressure, and the design load capacity
of the power end is the maximum load of the piston rod under the rated pressure corresponding to the
minimum liner bore;
— line pipe thread shall not be used for connection for discharge pipe line of fluid end, when the size of
connection is greater than 50 mm (2 in) or the rated pressure value is greater than 34,5 MPa (5 000 psi).
6.2.3 Series and main parameters
The series, rated input power and main parameters of the mud pump should conform to the specifications
listed in Table 1.
Table 1 — Series and main parameters of mud pump
Maximum pump pres- Maximum theoretical displace-
Rated input power
sure ment
Series
kW(hp)
MPa (psi) L/s
500 373 (500) 27,6 (4 000) 35
800 597 (800) 34,5 (5 000) 38,5
1 000 746 (1 000) 34,5 (5 000) 40
1 300 969 (1 300) 34,5 (5 000) 42,5
1 600 1 193 (1 600) 34,5 (5 000) 46
1 600 1 193 (1 600) 51,7 (7 500) 46
2 200 1 641 (2 200) 51,7 (7 500) 65
NOTE The mud pump series are expressed in imperial horsepower (hp).

TTabablele 1 1 ((ccoonnttiinnueuedd))
Maximum pump pres- Maximum theoretical displace-
Rated input power
sure ment
Series
kW(hp)
MPa (psi) L/s
2 200 1 641 (2 200) 69,0 (10 000) 65
3 000 2 237 (3 000) 51,7 (7 500) 76
3 000 2 237 (3 000) 69,0 (10 000) 76
NOTE The mud pump series are expressed in imperial horsepower (hp).
6.2.4 Technical parameters and rating values
6.2.4.1 Relationship among main parameters
The relationship among main parameters can be expressed as follows:
PN /Q (1)
00 0
where
P is the rated pressure at a certain diameter of liner bore, in megapascal (MPa);
η is the total pump efficiency. It is the product of mechanical, volumetric and hydraulic efficiencies.
In general, η ≈ 0,90;
N is the rated input power, in kilowatt (kW);
Q is the rated displacement at a certain diameter of liner bore, in litres per second (L/s).
6.2.4.2 Pump theoretical displacement
The theoretical displacement of pump can be expressed as Formula (2):
QiFSn/(6010 ) (2)
where
Q is the theoretical displacement of pump at a certain diameter of liner bore, in litres per second
(L/s);
i is the liners or pistons number;
F is the corresponding area at a certain diameter of liner bore in square millimetre;
S is the stroke in millimetre (mm);
n is the pump speed per minute (spm).
Formula (2) can be rewritten as Formula (3)
82
Qi1,309 10 DSn (3)
where D is the diameter of liner bore in millimetres.
In Formula (2) and Formula (3), the rated pump speed n is substituted for n. The rated displacement Q of
0 0
pump at specified diameter of liner bore can be calculated by Formula (4):
82
Qi1,309 10 DSn (4)
0 0
is the rated displacement in litres per second (L/s);
Q
is the rated pump speed per minute (spm).
n
6.2.4.3 Rated input power
For the rated input power, see 6.2.3 and Table 1.
For the pinion shaft dimensions of mud pump, refer to Annex B.
6.2.4.4 Maximum pump pressure
For the maximum pump pressure, see 6.2.3 and Table 1. If the rated pressure P at the minimum or the
smaller diameter of liner, calculated by Formula (1), exceeds the maximum pump pressure, the maximum
pump pressure shall be selected for rated pressure at the diameter of liner bore.
6.2.5 Scope of the primary load-carrying components and expendable items
6.2.5.1 The components that bear the main load at power end are considered as the primary load-carrying
components at the power end, including the frame, pinion shaft, gear, crankshaft, bearing, main bearing
bolt, connecting rod and crosshead pin, etc.
6.2.5.2 The primary pressure-containing components of fluid end include fluid cylinder, discharge
manifold, discharge five-way, the shell of discharge filter, the shell of discharge pulsation dampener and the
spool of discharge relief valve, etc.
6.2.5.3 The expendable items generally include crosshead extension rod wiper, cylinder liner, piston, valve
assembly, valve spring and rubber parts of fluid end.
6.2.6 Materials
6.2.6.1 The materials specified in this document refer to the metallic materials of the main load-carrying
components, and other non-metallic materials may refer to other related standards. All materials shall
be selected by the supplier/manufacturer and conform to the requirements outlined in the functional
specifications. The supplier/manufacturer shall have written specifications for all materials used in the
primary load-carrying components.
6.2.6.2 For metal materials specified in the supplier/manufacturer specification, the followings shall be
considered:
a) chemical composition;
b) mechanical property:
1) tensile strength;
2) yield strength;
3) hardness.
6.2.6.3 The material requirements of the primary pressure load-carrying components shall be in
accordance with ISO 14693:2003, Clause 6 and low temperature impact testing shall be performed
according to the requirements specified in ISO 148-1. The minimum average Charpy impact energy of three
full-size test pieces tested at the specified (or lower) temperature shall be 27 J, with no individual value less
than 20 J.
6.2.6.4 The material test reports provided by the material supplier or manufacturer can be used to verify
the consistency between the materials and the specifications.
6.2.7 Design requirements
6.2.7.1 Gears
For the gear transmission mud pump, gears shall be single reduction, either helical or herringbone. The gear
load calculation shall conform to ISO 6336-1, ISO 6336-2, ISO 6336-3 and ISO 6336-5. During the calculation,
the application factor shall not be lower than 1,25; the safety factor for bending strength shall not be less
than 2,0, and the safety factor for contact strength shall not be less than 1,25. The accuracy grade of the gears
shall ensure that the tooth-surface contact pattern is not less than 60 % along the tooth length direction and
not less than 45 % along the tooth height direction.
6.2.7.2 Bearing
6.2.7.2.1 Bearing as the primary load–carrying components, rolling bearings are recommended. The
tolerance class of rolling bearings shall not be less than the normal tolerance class specified in ISO 492. The
radial clearance of the main bearings and pinion shaft bearings shall not be more than Group Gr3 specified
in ISO 5753-1.
6.2.7.2.2 The reasonable service life for bearings shall not be less than 20 000 hours, under the rated input
power and rated pump speed.
6.2.7.3 Lubrication
The gear, bearing, crosshead, crosshead guide of mud pumps shall be fully lubricated. The mud pump should
preferably adopt a combination of forced lubrication and splash lubrication. There are generally two forced
lubrication solutions: built-in lubrication and external electric lubrication. In case the user/purchaser does
not specify, the built-in lubrication should be preferentially implemented.
6.2.7.4 Crosshead, crosshead extension, and piston rod connection-contacting flat faces and pilot
diameters
On triplex mud pumps, all rod connections among the crosshead, crosshead extension, and piston rod that
affect rod alignment shall have tolerances that do not exceed those shown in Figure 1.

Key
1 contacting face diameter
a
Contacting flat faces or mating rod connections, and crosshead extension shall be perpendicular to centreline
of rod with a tolerance of 0,000 5 m/m (0.0005 in./in.) of face diameter.
b
Concentricity tolerance between pilot diameter’s centreline and theoretical centreline of rod shall not exceed
0,13 mm (0.005 in.).
Figure 1 — Crosshead, crosshead extension, and piston rod connection-contacting flat faces and
pilot diameters for mud pumps
6.2.7.5 Piston rod and piston body bore
6.2.7.5.1 Sizes and dimensions
Mud pump piston rod and piston body bore shall be in conformance with the size and dimension stated in
Figure 2 and Table 2.
Table 2 — Mud pump fluid end piston rod and piston body bore
Dimensions in millimetres
Piston rod
Connection
From
Nominal
Piston
number be-
Piston rod di- shoulder Shoulder
con-
rod end
tween piston Piston bore
ameter to thread diameter
nection
Thread size
length
and Piston
start
diameter
rod
A B ±1,6 D ±0,4
C
max
SA-2 25,4 25,32 to 25,38 106,4 38,1 50,8 1-8UNC-2A 25,40 to 25,48
SA-3 25,4 25,32 to 25,38 106,4 38,1 50,8 M24-6g 25,40 to 25,48
SA-4 38,1 38,02 to 38,07 138,1 47,6 82,6 1 -8UN-2A 38,10 to 38,18
SA-5 42,0 41,92 to 41,97 148,0 65,0 90,0 M39×3-6g 42,00 to 42,08
NOTE 1 The No. SA-2 & SA-4 is used on the imperial mud pump.
NOTE 2 The No. SA-3 & SA-5 is used on the metric mud pump.

Dimensions in millimetres
Key
1 piston rod
2 piston sealing ring
3 piston
4 piston nut
a
The structure and dimension of thread recess and shoulder are based on the options of supplier/manufacturer.
Figure 2 — Mud pump fluid end piston rod and piston body bore
6.2.7.5.2 Thread
The thread on the piston rod end and piston nut shall conform to the sizes stated in Table 2.
6.2.7.6 Mud pump cylinder valve pot
6.2.7.6.1 Size and dimension
Cylinder valve pot shall be in accordance with the size and dimension requirements stated in Figure 3 and
Table 3.
Table 3 — Mud pump valve pot
Dimensions in millimetres
Valve pot dimension Spring mounting dimension
Pot size
A Cmin D E F Gmin Jmin L M N
4 111,1 34,9 120,7 20,6 69,9 104,8 69,9 50,8 76,2 95,3
5 127,0 38,1 136,5 33,3 76,2 123,8 79,4 69,9 95,3 108,0
6 142,9 44,5 152,4 33,3 82,6 133,4 85,7 69,9 95,3 114,3
7 158,8 50,8 168,3 33,3 88,9 142,9 95,3 69,9 95,3 120,7
8 177,8 57,2 187,3 33,3 95,3 152,4 98,4 69,9 95,3 127,0
Figure 3 — Mud pump valve pot
6.2.7.6.2 Spring mounting dimension
Valve pot spring mounting dimensions shall conform to dimensions L, M and N in Figure 3 and Table 3.
6.2.7.7 Mud pump liners
6.2.7.7.1 Liner bores
The specification of liner size (see Figure 4, size A) should be selected by metric system or imperial system.
The metric liner size should be an integer with zero digit and shall increase by each 10 mm (see Table 4). In
imperial system, bore of mud pump liners 152,4 mm in diameter and larger shall be supplied in 6,35 mm

increments; bores smaller than 152,4 mm in diameter shall be supplied in 12,7 mm increments (see Table 5).
Bore tolerances shall be as noted in Figure 4.
Dimensions in millimetres
Figure 4 — Mud pump liner
Table 4 — Metric liner bore diameter serials
Dimensions in millimetres
a
Liner bore 90 100 110 120 130 140 150 160 170 180 190
a
The dimensions not listed in the table may be applied as well, on the condition that they fully conform to the requirements of
6.2.7.7.1.
Table 5 — Imperial liner bore diameter serials
in 3.50 4.00 4.50 5.00 5.50 6.00 6.25 6.50 6.75 7.00
Liner
a
bore
mm 88,90 101,60 114,30 127,00 139,70 152,40 158,75 165,10 171,45 177,80
a
The dimensions not listed in the table may be applied as well, on the condition that they fully conform to the require-
ments of 6.2.7.7.1.
6.2.7.7.2 The surface roughness and hardness of Inner bore for liner
The surface roughness of liner bore shall be not greater than R 0,20 μm.
a
For bi-metal liners, its inner surface hardness shall be 60 HRC to 65 HRC.
For ceramic liners, the zirconia content of their inner sleeves shall be not less than 25 %, and the surface
hardness of their inner sleeves shall be not less than 87 HRA.
6.2.7.7.3 Chamfer
The inside edge of liners on the piston entering end shall be chamfered as shown in Figure 4.
6.2.7.8 Piston
The piston body bore shall be in accordance with Figure 2 and Table 2. Piston outside diameters shall be
conformed to the provisions of liner bore diameter in 6.2.7.7.1 and Figure 4.

6.2.7.9 Discharge flange
The discharge flange shall conform to the size and dimension requirements of Table 6 and ISO 10423. The
actual bore diameter of the flange can be less than or equal to the nominal size of the flange.
Table 6 — Discharge flange
Max. pump pressure 27,6 MPa 34,5 MPa 51,7 MPa 69,0 MPa
34,5 MPa 69,0 MPa
Flange Type
6B 6BX
Flange Nominal Size 103 mm or 130 mm
6.2.7.10 Suction flange
The size and dimension of suction flange shall conform to the requirements of Figure 5 and Table 7. Bolt
holes shall be equally spaced on bolt circle diameter.
Dimensions in millimetres
Figure 5 — Suction flange
Table 7 — Sizes and dimensions of suction flange
The diameter of
Bolt circle dia
The number of
bolt hole
Flange size OD T Thread size
bolt holes
(BC)
(d)
mm(in.) mm mm mm mm mm n
+2
15,
200 (8) 337,0 ± 0 3 285,8 M24 12
25,5
�0
05,
+2
15,
250 (10) 406,5 ± 0,3 30 362,0 M24 12
25,5
�0
05,
+2
15,
300 (12) 457,0 ± 0,3 400,0 28,5 M27 12
�0
05,
6.2.7.11 Connecting flange at the bottom of the pulsation dampener
Connecting flange at the bottom of the pulsation dampener shall conform to the requirements of ISO 10423.
According to the rated pressure of the pulsation dampener, the type 6B flange of 103 mm 34,5 MPa or the
type 6BX flange of 103 mm 69,0 MPa shall be selected.
6.2.7.12 Discharge relief valve
6.2.7.12.1 Discharge relief valve types
Mud pump shall be equipped with discharge relief valve for safety. Discharge relief devices typically include
types such as shear pin relief valve, spring reset relief valve, and rupture discs. The user/purchaser shall
specify which type to use.
6.2.7.12.2 Connection types
The outlet and inlet of discharge relief valve should adopt either union or flange connection.
6.2.7.12.3 Sizes and dimensions
The outlet and inlet of discharge relief valve shall have the following sizes and dimensions of union or flange:
a) when the union connection is adopted, unions with the nominal size of 80 mm (3 in) shall be selected;
b) when the flange connection is adopted, the flange shall conform to the requirements of ISO 10423.
According to the rated pressure of the relief valve, the type 6B flange of 79 mm (3 1/8 in) × 34,5 MPa
or the type 6BX flange of 78 mm (3 1/16 in) × 69,0 MPa or the type 6BX flange of 52 mm (2 1/16 in) ×
69,0 MPa shall be selected.
6.2.7.12.4 Discharge relief valve precision
The pressure error of the discharge relief valve shall be less than ±10 % of the nominal bleed pressure.
6.2.7.13 Discharge pressure gauge
6.2.7.13.1 Connection types
The discharge pressure gauge of the mud pump should be an anti-vibration pressure gauge with a union or
flange connection.
6.2.7.13.2 Sizes and dimensions
When the union connection is adopted, unions with the nominal size of 50 mm (2 in) shall be selected.

When the flange connection is adopted, the flange shall conform to the provisions of ISO 10423. According to
the maximum pump pressure, the type 6B flange of 52 mm (2 1/16 in) × 34,5 MPa or the type 6BX flange of
52 mm × 69,0 MPa shall be selected.
The dial diameter of the pressure gauge shall be at least 100 mm (4 in). The pressure shall be measured
within the range of 25 % to 75 % of the full scale of the pressure gauge. The accuracy of the pressure gauge
or pressure sensor shall not exceed ±2,5 % of the full scale.
6.2.7.14 Discharge pulsation dampener volume
For 500 and 800 series mud pumps, the volume of the discharge pulsation dampener shall not be less than
45 L. For mud pumps above 1 000 series, the volume of the discharge pulsation dampener shall not be less
than 75 L.
6.2.7.15 Health, safety, environment (HSE) requirements
6.2.7.15.1 For all exposed rotating parts such as the outer part of pinion shaft shall be provided with a
safety cover.
6.2.7.15.2 A protection cover shall be provided for the opening hole on the frame above the liners.
6.2.7.15.3 Overflow observation holes shall be designed at the rubber-sealed parts of the fluid end that
are frequently disassembled. The operator can detect whether there are leaks at each seal and replace the
sealing rings in a timely manner.
6.2.7.15.4 Protection cover shall be provided for the exposed sensors.
6.2.7.15.5 As minimum, mud pump shall be equipped with tools of sockets for bolts connection, cylinder
liner li
...

ISO/DISFDIS 24826:2026(en)
ISO/TC 67/SC 4
Secretariat: ANSI
Date: 2026-06-3009-15
Oil and gas industries including lower carbon energy — Drilling,
production and injection equipment — Mud pumps
Industries du pétrole et du gaz, y compris les énergies à faible teneur en carbone — Équipements de forage, de
production et d'injection — Pompes à boue
FDIS stage
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
EmailE-mail: [e-mail]
Website: www.iso.org
Published in Switzerland
ii
Contents
Foreword . iv
Introduction . v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 2
4 Symbols and abbreviations . 3
4.1 Symbols . 3
4.2 Abbreviated terms . 3
5 Functional specification . 4
5.1 General. 4
5.2 Mud pumps type description . 4
5.3 Functional requirements . 4
5.4 User/purchaser selections . 4
6 Technical specification . 5
6.1 General. 5
6.2 Design criteria . 5
7 Supplier/manufacturer requirements . 19
7.1 Test and inspection . 19
7.2 Marking . 23
7.3 Quality control . 24
7.4 Documentation . 26
8 Storage, packing and transportation . 27
8.1 General. 27
8.2 Storage . 27
8.3 Packing and transportation . 28
9 Installation, operation, and maintenance . 28
9.1 Basic requirements . 28
9.2 Installation . 29
9.3 Preparation before operation . 29
9.4 Operation principle of mud pump . 29
9.5 Trouble symptoms of mud pump . 30
Annex A (informative) Nomenclature of principal parts of piston mud pump . 32
Annex B (informative) The pinion shaft dimensions of mud pump . 41
Annex C (informative) Example of marks . 43
Annex D (informative) Configuration of mud pump . 44
Bibliography . 47

iii
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 document 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 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 67, Oil and gas industries including lower carbon
energy, Subcommittee SC 4, Drilling, production and injection equipment.
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.
iv
Introduction
This document has been prepared by users/purchasers and suppliers/manufacturers of mud pumps and is
intended for use in the petroleum and natural gas industries worldwide. This document provides
requirements and information to both parties in the selection, manufacturing, testing and use of mud pumps.
FurtherFurthermore, this document addresses supplier specifications and provides the components
composition diagram of the mud pump, (see Annex AAnnex A.).
v
Oil and gas industries including lower carbon energy — Drilling,
production and injection equipment — Mud pumps
1 Scope
This document provides the requirements for the design, design verification and confirmation, quality control,
product marking, storage, packaging and transportation, installation, operation and maintenance of single-
action piston mud pumps utilized in the petroleum and natural gas industries.
This document applies to the components of mud pumps, including the power end and fluid end components.
Note This document aligns with applicable laws and regulations of the destination countries and regions, such
as the European Union, Norway, the United States, etc.
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 148--1, Metallic materials — Charpy pendulum impact test — Part 1: Test method
ISO 492, Rolling bearings — Radial bearings — Geometrical product specifications (GPS) and tolerance values
ISO 780, Packaging — Distribution packaging — Graphical symbols for handling and storage of packages
ISO 4986, Steel and iron castings — Magnetic particle testing
ISO 5753--1, Rolling bearings — Internal clearance — Part 1: Radial internal clearance for radial bearings
ISO 6336--1, Calculation of load capacity of spur and helical gears — Part 1: Basic principles, introduction and
general influence factors
ISO 6336--2, Calculation of load capacity of spur and helical gears — Part 2: Calculation of surface durability
(pitting)
ISO 6336--3, Calculation of load capacity of spur and helical gears — Part 3: Calculation of tooth bending
strength
ISO 6336--5, Calculation of load capacity of spur and helical gears — Part 5: Strength and quality of materials
ISO 9934--1, Non-destructive testing — Magnetic particle testing — Part 1: General principles
ISO 9934--2, Non-destructive testing — Magnetic particle testing — Part 2: Detection media
ISO 9934--3, Non-destructive testing — Magnetic particle testing — Part 3: Equipment
ISO 10423, Petroleum and natural gas industries — Drilling and production equipment — Wellhead and tree
equipment
1)
ISO 14693:2003, , Petroleum and natural gas industries — Drilling and well-servicing equipment

1)
Withdrawn.
MSS SP-55, Quality Standard for Steel Castings for Valves, Flanges and Fittings and Other Piping Components —
Visual Method for Evaluation of Surface Irregularities
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
mud pump
key equipment used to pump drilling fluid to downhole during the process of drilling or workover
Note 1 to entry: Generally, it is the positive displacement reciprocating pump.
3.2 3.2
fluid cylinder
shell in which valve assembly, liner, suction manifold and discharge manifold are installed and through which
high pressure fluid is passed
3.3 3.3
valve pot
inside the cylinder, where the valve assembly and valve spring are installed
3.4 3.4
discharge pulsation dampener
airtight container with sufficient air/nitrogen mounted at the discharge manifold of pump
3.5 3.5
discharge relief valve
relief valve is set to ensure the pump discharge pressure does not exceed a certain allowable value
3.6 3.6
stroke
moving distance of piston from the front starting point to the back-end point during the operation of mud
pump
3.7 3.7
pump speed
number of reciprocating motions per minute for a piston
3.8 3.8
rated pressure
maximum pressure allowed by a mud pump at a specified size of liner
Note 1 to entry: The rated pressure of the mud pump varies with the liner size.

3.9 3.9
maximum pump pressure
maximum working pressure allowed by a mud pump at the minimum size of liner
Note 1 to entry: The maximum pump pressure of a mud pump has only one value.
3.10 3.10
discharge pressure nonuniformity
ratio of the maximum fluctuating pressure to the average pressure in the mud pump discharge manifold
3.11 3.11
primary pressure-containing components of fluid end
components of the fluid end through which the discharge pressure is carried, except expendable parts and
seals
3.12 3.12
consumable parts
parts are designed to be used up, depleted, or worn out during the normal operation of mud pump and needs
to be regularly replaced or replenished
3.13 3.13
maintenance
measures which are taken to maintain the service performance of the equipment
Note 1 to entry: Including inspection, adjustment, cleaning, lubrication, testing, consumable parts replacement, etc.
4 Symbols and abbreviations
4.1 Symbols
𝑃𝑃 rated pressure under a certain liner bore
η overall efficiency of the pump
𝑁𝑁 rated input power
𝑄𝑄 rated flow rate under a certain liner bore
Q theoretical flow rate of the pump at a certain liner bore
i number of liners or pistons
F the area corresponding to a certain liner bore
S stroke
n pump speed
D liner bore
𝑄𝑄 rated flow rate under each liner
𝑛𝑛 rated pump impulse under each liner
4.2 Abbreviated terms
FEA finite element analysis
NDT non-destructive test
PQR procedure qualification record
OEM original equipment manufacturer
5 Functional specification
5.1 General
The user/purchaser shall prepare a functional specification to order products that conform to this document,
and to specify the requirements and operating conditions of mud pump. The user/purchaser shall specify the
units of measurement for the data provided. This information is used by the supplier/manufacturer to
recommend the mud pumps for application conditions.
5.2 Mud pumps type description
The user/purchaser shall order the triplex or quintuplex mud pump according to the production
requirements.
5.3 Functional requirements
5.3.1 General
The user/purchaser should clarify the known and expected application parameters and requirements.
5.3.2 Necessary functional parameters
The user/buyer shall specify the following application parameters:
— — rated power;
— — maximum displacement;
— — maximum pump pressure;
— — ambient operating temperature.
5.3.3 Other parameters or requirements
The user/buyer should specify the following parameters or requirements:
— — mud density and pH value;
— — shipping requirements;
— — requirements for delivery documents;
— — testing and acceptance requirements;
— — others.
5.4 User/purchaser selections
The user/purchaser selections shall be specified as follows:
— — the connecting thread of metric pumps is metric thread, and the liner piston is also metric thread;
— — the specifications of the liner and piston assembled inside the mud pump before the mud pumps
delivery;
— — the internal gear lubrication oil pump or external electric lubrication oil pump shall be determined. If
an external electric lubrication oil pump is used, the voltage, frequency, and explosion-proof requirements
of the motor;
— — mechanical spray pump or electric spray pump shall be determined. If an electric spray pump is used,
the voltage, frequency, and explosion-proof requirements of the motor;
— — the forged pulsation dampener or cast pulsation dampener;
— — the shear pin relief valve or the spring reset relief valve.
6 Technical specification
6.1 General
The supplier/manufacturer shall prepare a technical specification to respond to the requirements in the
functional specification, or to identify in detail the differences from the requirements in the functional
specification.
6.2 Design criteria
6.2.1 General
The design of the mud pump shall meet its intended applications and reliability requirements. Each
component of the mud pump shall be capable of safely transmitting the specified loads and power. The design
of the mud pump shall ensure the safe operation of the equipment. The supplier/manufacturer shall
demonstrate the product conformity to the design and performance requirements specified in 6.2.86.2.8 and
6.2.96.2.9.
6.2.2 Design conditions
The following design conditions shall apply:
— — the mud pump is designed to operate under continuously working conditions;
— — the series and main technical parameters of the mud pump should conform to the provisions of
6.2.36.2.3;;
— — a low-temperature impact test at -20 °C shall be required for the materials of the primary pressure-
containing components of fluid end of the mud pump. The design load capacity of the fluid end is the
maximum discharge pressure, and the design load capacity of the power end is the maximum load of the
piston rod under the rated pressure corresponding to the minimum liner bore;
the design load capacity of the fluid end is the maximum discharge pressure, and the design load
— —
capacity of the power end is the maximum load of the piston rod under the rated pressure corresponding
to the minimum liner bore;
— — line pipe thread shall not be used for connection for discharge pipe line of fluid end, when the size of
connection is greater than 50 mm (2 in) or the rated pressure value is greater than 34,5 MPa (5 000 psi).
6.2.3 Series and main parameters
The series, rated input power and main parameters of the mud pump should conform to the specifications
listed in Table 1Table 1.
Table 1 — Series and main parameters of mud pump
Maximum pump Maximum theoretical
Rated input power
pressure displacement
Series
kW(hp)
MPa (psi) L/s
500 373 (500) 27,6 (4 000) 35
800 597 (800) 34,5 (5 000) 38,5
1 000 746 (1 000) 34,5 (5 000) 40
1 300 969 (1 300) 34,5 (5 000) 42,5
1 600 1 193 (1 600) 34,5 (5 000) 46
1 600 1 193 (1 600) 51,7 (7 500) 46
2 200 1 641 (2 200) 51,7 (7 500) 65
2 200 1 641 (2 200) 69,0 (10 000) 65
3 000 2 237 (3 000) 51,7 (7 500) 76
3 000 2 237 (3 000) 69,0 (10 000) 76
NOTE The mud pump series are expressed in imperial horsepower (hp).
6.2.4 Technical parameters and rating values
6.2.4.1 Relationship among main parameters
The relationship among main parameters can be expressed as follows:
𝑃𝑃 =𝜂𝜂 ×𝑁𝑁 /𝑄𝑄 (1)
0 0 0
where
𝑃𝑃 is the rated pressure at a certain diameter of liner bore, in megapascal (MPa);
𝜂𝜂 is the total pump efficiency. It is the product of mechanical, volumetric and hydraulic efficiencies. In general, η ≈
0,90;
𝑁𝑁 is the rated input power, in kilowatt (kW);
𝑄𝑄 is the rated displacement at a certain diameter of liner bore, in litres per second (L/s).
6.2.4.2 Pump theoretical displacement
The theoretical displacement of pump can be expressed as Formula (2)Formula (2)::
𝑄𝑄 =𝑖𝑖 ×𝐹𝐹 ×𝑆𝑆 ×𝑛𝑛/(60 × 10 ) (2)
where
Q is the theoretical displacement of pump at a certain diameter of liner bore, in litres per second (L/s);
𝑖𝑖 is the liners or pistons number;
F is the corresponding area at a certain diameter of liner bore in square millimetre;
S is the stroke in millimetre (mm);
𝑛𝑛 is the pump speed per minute (spm).
Formula (2)Formula (2) can be rewritten as Formula (3)Formula (3)
−8 2
𝑄𝑄 = 1,309 × 10 ×𝑖𝑖 ×𝐷𝐷 ×𝑆𝑆 ×𝑛𝑛 (3)
where 𝐷𝐷 is the diameter of liner bore in millimetres.
In Formula (2)Formula (2) and Formula (3)Formula (3),, the rated pump speed n is substituted for n. The
rated displacement Q of pump at specified diameter of liner bore can be calculated by
Formula (4)Formula (4)::
(4)
−8 2
𝑄𝑄 = 1,309 × 10 ×𝑖𝑖 ×𝐷𝐷 ×𝑆𝑆 ×𝑛𝑛 (4)
0 0
𝑄𝑄 is the rated displacement in litres per second (L/s);
𝑛𝑛 is the rated pump speed per minute (spm).
6.2.4.3 Rated input power
For the rated input power, see 6.2.36.2.3 and Table 1Table 1.
For the pinion shaft dimensions of mud pump, refer to Annex BAnnex B.
6.2.4.4 Maximum pump pressure
For the maximum pump pressure, see 6.2.36.2.3 and Table 1Table 1. If the rated pressure 𝑃𝑃 at the minimum
or the smaller diameter of liner, calculated by Formula (1) (1),, exceeds the maximum pump pressure, the
maximum pump pressure shall be selected for rated pressure at the diameter of liner bore.
6.2.5 Scope of the primary load-carrying components and expendable items
6.2.5.1 6.2.5.1 The components that bear the main load at power end are considered as the
primary load-carrying components at the power end, including the frame, pinion shaft, gear, crankshaft,
bearing, main bearing bolt, connecting rod and crosshead pin, etc.
6.2.5.2 6.2.5.2 The primary pressure-containing components of fluid end include fluid
cylinder, discharge manifold, discharge five-way, the shell of discharge filter, the shell of discharge pulsation
dampener and the spool of discharge relief valve, etc.
6.2.5.3 6.2.5.3 The expendable items generally include crosshead extension rod wiper,
cylinder liner, piston, valve assembly, valve spring and rubber parts of fluid end.
6.2.6 Materials
6.2.6.1 6.2.6.1 The materials specified in this document refer to the metallic materials of the
main load-carrying components, and other non-metallic materials may refer to other related standards. All
materials shall be selected by the supplier/manufacturer and conform to the requirements outlined in the
functional specifications. The supplier/manufacturer shall have written specifications for all materials used
in the primary load-carrying components.
6.2.6.2 6.2.6.2 For metal materials specified in the supplier/manufacturer specification, the
followings shall be considered:
a) a) chemical composition;
b) b) mechanical property:
1) 1) tensile strength;
2) 2) yield strength;
3) 3) hardness.
6.2.6.3 6.2.6.3 The material requirements of the primary pressure load-carrying components
shall be in accordance with ISO 14693:2003, Chapter Clause 6 and low temperature impact testing shall be
performed according to the requirements specified in ISO 148-1. The minimum average Charpy impact energy
of three full-size test pieces tested at the specified (or lower) temperature shall be 27 J, with no individual
value less than 20 J.
6.2.6.4 6.2.6.4 The material test reports provided by the material supplier or manufacturer
can be used to verify the consistency between the materials and the specifications.
6.2.7 Design requirements
6.2.7.1 Gears
For the gear transmission mud pump, gears shall be single reduction, either helical or herringbone. The gear
load calculation shall conform to ISO 6336-1, ISO 6336-2, ISO 6336-3 and ISO 6336-5. During the calculation,
the application factor shall not be lower than 1,25; the safety factor for bending strength shall not be less than
2,0, and the safety factor for contact strength shall not be less than 1,25. The accuracy grade of the gears shall
ensure that the tooth-surface contact pattern is not less than 60 % along the tooth length direction and not
less than 45 % along the tooth height direction.
6.2.7.2 Bearing
6.2.7.2.1 6.2.7.2.1 Bearing as the primary load–carrying components, rolling bearings are
recommended. The tolerance class of rolling bearings shall not be less than the normal tolerance class
specified in ISO 492. The radial clearance of the main bearings and pinion shaft bearings shall not be more
than Group Gr3 specified in ISO 5753-1.
6.2.7.2.2 6.2.7.2.2 The reasonable service life for bearings shall not be less than 20 000 hours,
under the rated input power and rated pump speed.
6.2.7.3 Lubrication
The gear, bearing, crosshead, crosshead guide of mud pumps shall be fully lubricated. The mud pump should
preferably adopt a combination of forced lubrication and splash lubrication. There are generally two forced
lubrication solutions: built-in lubrication and external electric lubrication. In case the user/purchaser does
not specify, the built-in lubrication should be preferentially implemented.
6.2.7.4 Crosshead, crosshead extension, and piston rod connection-contacting flat faces and pilot
diameters
On triplex mud pumps, all rod connections among the crosshead, crosshead extension, and piston rod that
affect rod alignment shall have tolerances that do not exceed those shown in Figure 1Figure 1.
Key
1 contacting face diameter
a
Contacting flat faces or mating rod connections, and crosshead extension shall be perpendicular to centreline of rod with a
tolerance of 0,000 5 m/m (0.0005 in./in.) of face diameter.
b
Concentricity tolerance between pilot diameter’s centreline and theoretical centreline of rod shall not exceed 0,13 mm (0.005 in.).
Figure 1 — Crosshead, crosshead extension, and piston rod connection-contacting flat faces and pilot
diameters for mud pumps
6.2.7.5 Piston rod and piston body bore
6.2.7.5.1 Sizes and dimensions
Mud pump piston rod and piston body bore shall be in conformance with the size and dimension stated in
Figure 2Figure 2 and Table 2Table 2.
Table 2 — Mud pump fluid end piston rod and piston body bore
Dimensions in millimetres
Piston rod
Nomina
Connectio
From
l
n number
Piston shoulde
connect
Piston rod Shoulder
between Piston bore
rod end r to
ion diameter diameter
Thread size
length thread
piston and
diamet
start
Piston rod
er
A B ±1,6 C D ±0,4
max
SA-2 25,4 25,32 to 25,38 106,4 38,1 50,8 1-8UNC-2A 25,40 to 25,48
SA-3 25,4 25,32 to 25,38 106,4 38,1 50,8 M24-6g 25,40 to 25,48
SA-4 38,1 38,02 to 38,07 138,1 47,6 82,6 1 -8UN-2A 38,10 to 38,18
SA-5 42,0 41,92 to 41,97 148,0 65,0 90,0 M39×3-6g 42,00 to 42,08
NOTE 1 The No. SA-2 & SA-4 is used on the imperial mud pump.
NOTE 2 The No. SA-3 & SA-5 is used on the metric mud pump.
Dimensions in millimetres
Key
1 piston rod
2 piston sealing ring
3 piston
4 piston nut
a
The structure and dimension of thread recess and shoulder are based on the options of supplier/manufacturer.
Figure 2 — Mud pump fluid end piston rod and piston body bore
6.2.7.5.2 Thread
The thread on the piston rod end and piston nut shall conform to the sizes stated in Table 2Table 2.
6.2.7.6 Mud pump cylinder valve pot
6.2.7.6.1 Size and dimension
Cylinder valve pot shall be in accordance with the size and dimension requirements stated in Figure 3Figure 3
and Table 3Table 3.
Table 3 — Mud pump valve pot
Dimensions in millimetres
Spring mounting
Valve pot dimension
dimension
Pot size
A Cmin D E F Gmin Jmin L M N
4 111,1 34,9 120,7 20,6 69,9 104,8 69,9 50,8 76,2 95,3
5 127,0 38,1 136,5 33,3 76,2 123,8 79,4 69,9 95,3 108,0
6 142,9 44,5 152,4 33,3 82,6 133,4 85,7 69,9 95,3 114,3
7 158,8 50,8 168,3 33,3 88,9 142,9 95,3 69,9 95,3 120,7
8 177,8 57,2 187,3 33,3 95,3 152,4 98,4 69,9 95,3 127,0
Figure 3 — Mud pump valve pot
6.2.7.6.2 Spring mounting dimension
Valve pot spring mounting dimensions shall conform to dimensions L, M and N in Figure 3Figure 3 and
Table 3Table 3.
6.2.7.7 Mud pump liners
6.2.7.7.1 Liner bores
The specification of liner size (see Figure 4Figure 4,, size A) should be selected by metric system or imperial
system. The metric liner size should be an integer with zero digit and shall increase by each 10 mm (see
Table 4Table 4).). In imperial system, bore of mud pump liners 152,4 mm in diameter and larger shall be
supplied in 6,35 mm increments; bores smaller than 152,4 mm in diameter shall be supplied in 12,7 mm
increments (see Table 5Table 5).). Bore tolerances shall be as noted in Figure 4Figure 4.
Dimensions in millimetres
Figure 4— — Mud pump liner
Table 4 — Metric liner bore diameter serials
Dimensions in millimetres
a
Liner bore 90 100 110 120 130 140 150 160 170 180 190
a The dimensions not listed in the table may be applied as well, on the condition that they fully conform to the requirements of
6.2.7.7.1.
Table 5 — Imperial liner bore diameter serials
in 3.50 4.00 4.50 5.00 5.50 6.00 6.25 6.50 6.75 7.00
Liner
a m 101,6 114,3 139,7 152,4 158,7 165,1 171,4 177,8
bore
88,90 127,00
m 0 0 0 0 5 0 5 0
a
The dimensions not listed in the table may be applied as well, on the condition that they fully conform to the
requirements of 6.2.7.7.1.
6.2.7.7.2 The surface roughness and hardness of Inner bore for liner
The surface roughness of liner bore shall be not greater than 𝑅𝑅 0,20 μm.
𝑎𝑎
For bi-metal liners, its inner surface hardness shall be 60 HRC to 65 HRC.
For ceramic liners, the zirconia content of their inner sleeves shall be not less than 25 %, and the surface
hardness of their inner sleeves shall be not less than 87 HRA.
6.2.7.7.3 Chamfer
The inside edge of liners on the piston entering end shall be chamfered as shown in Figure 4Figure 4.
6.2.7.8 Piston
The piston body bore shall be in accordance with Figure 2Figure 2 and Table 2Table 2. Piston outside
diameters shall be conformed to the provisions of liner bore diameter in 6.2.7.7.16.2.7.7.1 and
Figure 4Figure 4.
6.2.7.9 Discharge flange
The discharge flange shall conform to the size and dimension requirements of Table 6Table 6 and ISO 10423.
The actual bore diameter of the flange can be less than or equal to the nominal size of the flange.
Table 6 — Discharge flange
Max. pump pressure 27,6 MPa 34,5 MPa 51,7 MPa 69,0 MPa
34,5 MPa 69,0 MPa
Flange Type
6B 6BX
Flange Nominal Size 103 mm or 130 mm
6.2.7.10 Suction flange
The size and dimension of suction flange shall conform to the requirements of Figure 5Figure 5 and
Table 7Table 7. Bolt holes shall be equally spaced on bolt circle diameter.
Dimensions in millimetres
Figure 5 — Suction flange
Table 7 — Sizes and dimensions of suction flange
Bolt circle The diameter
Flange The number
dia of bolt hole
OD T Thread size
size of bolt holes
(BC) (d)
mm(in.) mm mm mm mm mm n
+1,5
+2
200 (8) 337,0 ± 0 3 30 285,8 25, 5 M24 12
0 −0,5
+2 +1,5
250 (10) 406,5 ± 0,3 362,0 25, 5 M24 12
−0,5
+2 +1,5
300 (12) 457,0 ± 0,3 400,0 28, 5 M27 12
−0,5
6.2.7.11 Connecting flange at the bottom of the pulsation dampener
Connecting flange at the bottom of the pulsation dampener shall conform to the requirements of ISO 10423.
According to the rated pressure of the pulsation dampener, the type 6B flange of 103 mm 34,5 MPa or the type
6BX flange of 103 mm 69,0 MPa shall be selected.
6.2.7.12 Discharge relief valve
6.2.7.12.1 Discharge relief valve types
Mud pump shall be equipped with discharge relief valve for safety. Discharge relief devices typically include
types such as shear pin relief valve, spring reset relief valve, and rupture discs. The user/purchaser shall
specify which type to use.
6.2.7.12.2 Connection types
The outlet and inlet of discharge relief valve should adopt either union or flange connection.
6.2.7.12.3 Sizes and dimensions
The outlet and inlet of discharge relief valve shall have the following sizes and dimensions of union or flange:
a) a) when the union connection is adopted, unions with the nominal size of 80 mm (3 in) shall be
selected；;
b) b) when the flange connection is adopted, the flange shall conform to the requirements of ISO
10423. According to the rated pressure of the relief valve, the type 6B flange of 79 mm (3 1/8 in) ×
34,5 MPa or the type 6BX flange of 78 mm (3 1/16 in) × 69,0 MPa or the type 6BX flange of 52 mm (2 1/16
in) × 69,0 MPa shall be selected.
6.2.7.12.4 Discharge relief valve precision
The pressure error of the discharge relief valve shall be less than ±10 % of the nominal bleed pressure.
6.2.7.13 Discharge pressure gauge
6.2.7.13.1 Connection types
The discharge pressure gauge of the mud pump should be an anti-vibration pressure gauge with a union or
flange connection.
6.2.7.13.2 Sizes and dimensions
When the union connection is adopted, unions with the nominal size of 50 mm (2 in) shall be selected.
When the flange connection is adopted, the flange shall conform to the provisions of ISO 10423. According to
the maximum pump pressure, the type 6B flange of 52 mm (2 1/16 in) × 34,5 MPa or the type 6BX flange of
52 mm × 69,0 MPa shall be selected.
The dial diameter of the pressure gauge shall be at least 100 mm (4 in). The pressure shall be measured within
the range of 25 % to 75 % of the full scale of the pressure gauge. The accuracy of the pressure gauge or
pressure sensor shall not exceed ±2,5 % of the full scale.
6.2.7.14 Discharge pulsation dampener volume
For 500 and 800 series mud pumps, the volume of the discharge pulsation dampener shall not be less than
45 L. For mud pumps above 1 000 series, the volume of the discharge pulsation dampener shall not be less
than 75 L.
6.2.7.15 Health, safety, environment (HSE) requirements
6.2.7.15.1 6.2.7.15.1 For all exposed rotating parts such as the outer part of pinion shaft shall be
provided with a safety cover.
6.2.7.15.2 6.2.7.15.2 A protection cover shall be provided for the opening hole on the frame above
the liners.
6.2.7.15.3 6.2.7.15.3 Overflow observation holes shall be designed at the rubber-sealed parts of the
fluid end that are frequently disassembled. The operator can detect whether there are leaks at each seal and
replace the sealing rings in a timely manner.
6.2.7.15.4 6.2.7.15.4 Protection cover shall be provided for the exposed sensors.
6.2.7.15.5 6.2.7.15.5 As minimum, mud pump shall be equipped with tools of sockets for bolts
connection, cylinder liner lifting and manual pump.
6.2.7.15.6 6.2.7.15.6 Grounding marks, lifting marks shall be set in easily observed positions.
6.2.7.15.7 6.2.7.15.7 The necessary safety warning nameplate or mark regarding operation or
maintenance shall be provided as well.
6.2.8 Design Verification
6.2.8.1 6.2.8.1 The supplier/manufacturer shall conduct design validation to verify that the
product design meets the supplier/manufacturer's design criteria. The purpose of design verification is to
ensure that the product design output meets the design input requirements.
6.2.8.2 6.2.8.2 Design verification activities may consist of one or more of the listed items:
a) a) conduct design calculations using alternative calculation methods to ascertain the accuracy of
the design results;
b) b) conduct a review of design drawings and documents through activities independent of the
design and development process, such as customer or third-party audits;
c) c) compare the new design with proven similar designs.
6.2.8.3 6.2.8.3 Design verification documents shall be documented. Typically, these
documents include FEA (finite element analysis) reports, customer or third-party audit records, and
calculation documents for the new design with similar designs.
6.2.8.4 6.2.8.4 All design verification documents shall be incorporated into the product design
documentation and approved by a qualified personnel other than the initial designer.
6.2.8.5 6.2.8.5 FEA shall be conducted on the pump frame, crankshaft and all primary load-
carrying components of the fluid end.
6.2.9 Design validation
6.2.9.1 6.2.9.1 The design validation testing of the mud pump design shall be conducted to
verify that the product design meets the performance requirements. The purpose of design validation is to
ensure that the product’s performance conforms to the intended application. Design validation shall be
completed before delivery.
6.2.9.2 6.2.9.2 Design validation activities may consist of one or more of the listed items:
a) a) prototype type test;
b) b) factory acceptance test (FAT);
c) c) tests required by standards and/or regulations;
d) d) on-site operation test and review.
6.2.9.3 6.2.9.3 Design validation documents shall be documented. Typically, these documents
include material test reports, NDT reports, testing records, FAT report, user/ purchaser use reports, etc.
6.2.10 Design document
The design document shall include the following:
a) a) design criteria;
b) b) engineering drawings and bill of materials;
c) c) design verification documents;
d) d) design validation documents.
7 Supplier/manufacturer requirements
7.1 Test and inspection
7.1.1 Hydrostatic test
7.1.1.1 General
Primary pressure-containing components of the fluid end shall be hydrostatic tested. The test pressure shall
be 1,5 times the maximum pump pressure. Cast components of the mud-pump suction hydraulic circuit shall
be hydrostatically tested in production to twice the manufacturer's rated suction pressure. For the suction
line by self-suction or charging by centrifugal pump, hydrostatic testing pressure should be 1,6 MPa. Clean
water, water with additives, or the fluid normally used in actual service shall be used as the test fluid. Tests
shall be performed on the completed part or assembly before painting.
7.1.1.2 Test procedure
The hydrostatic test shall be carried out as follows:
a) a) the primary pressure-holding period;
b) b) the reduction of the test pressure to zero;
c) c) thorough drying of all external surfaces of the item being tested;
d) d) the secondary pressure-holding period.
Both pressure-holding periods shall not be less than 10 mins, the timing of which shall not start until the test
pressure has been reached, the equipment and the pressure-monitoring gauge have been isolated from the
pressure source, and the external surfaces of the body members have been thoroughly dried.
7.1.1.3 Qualification
After each test cycle, the test item shall be carefully inspected for the absence of leakage or permanent
deformation. Failure to meet this requirement or premature failure shall be the cause for a complete
reassessment of the design, followed by repetition of the test.
7.1.2 Factory acceptance test
7.1.2.1 Accuracy test of discharge relief valve
The relief valves shall be sampled for static pressure bleeding tests. The sampling ratio for each batch shall be
no less than 20 %, and the number of sampled valves shall not be less than 2 pieces. If any non - conformant
valves are found in the sample, each relief valve in this batch shall conduct the pressure bleeding test. Sampling
tests can be resumed only after the product quality becomes stable.
The test pressure shall be set at least at three levels: the lowest, the medium, and the highest values of the
relief valve's nominal bleed pressures. The number of tests for each level shall be no less than 2 times. The
medium pressure can be any pressure between the lowest and the highest pressures. During the test, the
discharge test pressure shall be slowly adjusted to gradually increase until the relief valve bleeds and releases
pressure. The error of the bleeding pressure shall be less than ±10 % of the nominal bleed pressures.
7.1.2.2 Air tightness test of discharge pulsation dampener
Discharge pulsation dampener assembly shall be air tightness tested after final-assembling. After the bladder
of dampener assembly is pressurized to the maximum inflation pressure specified in the design, fill nitrogen
or compressed air; close the cut-off valve; and hold the pressure for 24 hours; air pressure drop shall be lower
than 0,20 MPa.
7.1.2.3 Inspection of gear tooth surface contact accuracy
The inspection of gear tooth surface contact accuracy shall be performed before running test of mud pump.
The tooth - surface contact pattern is not less than 60 % along the tooth length direction and not less than
45 % along the tooth height direction. The distribution of the contact pattern should tend to be in the medium
of the tooth surface, and there should be no contact at the tooth tip and the edges of the tooth width.
7.1.2.4 Running test
7.1.2.4.1 7.1.2.4.1 Before delivery, the mud pump shall conduct running test up to 4 hours,
including:
a) a) idle running test;
b) b) gradually loading test;
c) c) load running test no less than 80 % rated input power, continually run for at least 2 hours.
7.1.2.4.2 7.1.2.4.2 Temperature rise of the oil tank and bearing cover shall not exceed 60 °C, and
the maximum temperature shall not exceed 90 °C. Noise measurements of the mud pump shall be conducted
no less than two times, and the noise levels shall comply with the requirements specified in
clause 7.1.2.5clause 7.1.2.5. The mud pump shall run smoothly, without
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