Special Purpose Couplings for Petroleum, Chemical and Gas Industry Services

API STANDARD 671

FOURTH EDITION, AUGUST 2007

ISO 10441:2007 (Identical), Petroleum, petrochemical and natural gas industries—Flexible couplings for mechanical power transmission—Special-purpose applications

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Copyright © 2007 American Petroleum Institute

API Foreword

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Contents Page

API Foreword ii

Foreword v

Introduction vi

1. Scope 1

2. Normative references 1

3. Terms and definitions 2

4. Statutory requirements 7

5. Coupling selection 7

6. Coupling design 9

7. Coupling ratings 11

8. Coupling requirements 12

   1. Metallic flexible-element couplings 12

   2. Machining 12

   3. Spacer 13

   4. Hub type 13

   5. Integral flanges 13

   6. Hubs 13

   7. Solo plate (idling adapter) 15

   8. Moment simulator 15

   9. Component fit tolerances and potential unbalance calculations 15

   10. Fasteners (including studs) 15

   11. Electrical insulation. 16

   12. Dynamics 16

9. Balance 17

   1. General 17

   2. Balancing methods 18

   3. Balance criteria 20

   4. Trim balance holes 23

10. Materials 24

11. Accessories 24

12. Manufacturing quality, inspection, testing and preparation for shipment 25

    1. Manufacturing quality 25

    2. Inspection and testing 25

    3. Inspection 26

    4. Testing 26

    5. Preparation for shipment 27

13. Vendor data 27

    1. General 27

    2. Proposals and contract data 28

Annex A (normative) Torsional damping couplings and resilient couplings 31

Annex B (normative) Gear couplings 34

Annex C (normative) Quill-shaft couplings 36

Annex D (informative) Factors for metallic element couplings 37

Annex E (informative) Example of the determination of potential unbalance 39

Annex F (informative) Examples of misalignments 43

Annex G (informative) Coupling tapers 44

Annex H (normative) Coupling guards 45

Annex I (informative) Procedure for residual unbalance check 47

Annex J (informative) Coupling datasheets 51

Bibliography 56

Foreword

ISO (the International Organization for Standardization) is a worldwide federation of national standards bodies (ISO member bodies). The work of preparing International Standards is normally carried out through ISO technical committees. Each member body interested in a subject for which a technical committee has been established has the right to be represented on that committee. International organizations, governmental and non-governmental, in liaison with ISO, also take part in the work. ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization.

International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 2.

The main task of technical committees is to prepare International Standards. Draft International Standards adopted by the technical committees are circulated to the member bodies for voting. Publication as an International Standard requires approval by at least 75 % of the member bodies casting a vote.

Attention is drawn to the possibility that some of the elements of this document may be the subject of patent rights. ISO shall not be held responsible for identifying any or all such patent rights.

ISO 10441 was prepared by Technical Committee ISO/TC 67, Materials, equipment and offshore structures for petroleum, petrochemical and natural gas industries, Subcommittee SC 6, Processing equipment and systems.

This second edition cancels and replaces the first edition (ISO 10441:1999), which has been technically revised.

Introduction

This International Standard was developed from the API Std 671, 3rd edition, 1998. It is intended that the 4th edition of API Std 671 will be identical to this International Standard.

Users of this International Standard should be aware that further or differing requirements may be needed for individual applications. This International Standard is not intended to inhibit a vendor from offering, or the purchaser from accepting alternative equipment or engineering solutions for the individual application. This may be particularly appropriate where there is innovative or developing technology. Where an alternative is offered, the vendor should identify any variations from this International Standard and provide details.

This International Standard requires the purchaser to specify certain details and features.

A bullet (●) at the beginning of a subclause or paragraph indicates that either a decision is required or further information is to be provided by the purchaser. This information should be indicated on the datasheet(s), typical examples of which are included as Annex J; otherwise it should be stated in the quotation request or in the order.

Petroleum, petrochemical and natural gas industries — Flexible couplings for mechanical power transmission — Special- purpose applications

1. Scope

   
   

   This International Standard specifies the requirements for couplings for the transmission of power between the rotating shafts of two machines in special-purpose applications in the petroleum, petrochemical and natural gas industries. Such applications are typically in large and/or high speed machines, in services that can be required to operate continuously for extended periods, are often unspared and are critical to the continued operation of the installation. By agreement, it can be used for other applications or services.

   
   

   Couplings covered by this International Standard are designed to accommodate parallel (or lateral) offset, angular misalignment and axial displacement of the shafts without imposing unacceptable mechanical loading on the coupled machines. It is applicable to gear, metallic flexible element, quill shaft and torsionally resilient type couplings. Torsional damping and resilient type couplings are detailed in Annex A; gear-type couplings are detailed in Annex B and quill shaft style couplings are detailed in Annex C.

   
   

   This International Standard covers the design, materials of construction, manufacturing quality, inspection and testing of special-purpose couplings.

   
   

   This International Standard does not define criteria for the selection of coupling types for specific applications.

   
   

   This International Standard is not applicable to other types of couplings, such as clutch, hydraulic, eddy-current, rigid, radial spline, chain and bellows types.

   
   

2. Normative references

The following referenced documents are indispensable for the application of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies.

ISO 262, ISO general-purpose metric screw threads — Selected sizes for screws, bolts and nuts

ISO 286-2, ISO system of limits and fits — Part 2: Tables of standard tolerance grades and limit deviations for holes and shafts

ISO 2491, Thin parallel keys and their corresponding keyways (Dimensions in millimetres)

ANSI Y14.2M1), Line Conventions and Lettering

ANSI/AGMA 90002), Flexible Couplings — Potential Unbalance Classification ANSI/AGMA 9002, Bores and Keyways for Flexible Couplings (Inch Series) ANSI/AGMA 9003, Flexible Couplings — Keyless Fits

1. American National Standards Institute, 25 West 43rd Street, 4th Floor, New York, NY 10036, USA.

2. American Gear Manufacturers Association, 500 Montgomery Street, Suite 350, Alexandria, VA 22314-1560, USA.