Specification for Pumping Units

API SPECIFICATION 11E

NINETEENTH EDITION, NOVEMBER 2013 EFFECTIVE DATE: MAY 1, 2014

ERRATA, AUGUST 2015

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Copyright © 2013 American Petroleum Institute

Foreword

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Contents

Page

1. Scope 1

2. Normative References 1

3. Terms, Definitions, Abbreviations, and Symbols 2

   1. Terms and Definitions 2

   2. Abbreviations and Symbols 4

4. Product Requirements 7

   1. Functional Requirements 7

   2. Technical Requirements 8

5. Beam Pump Structure Requirements 9

   1. General 9

   2. Design Loads for All Structural Members Except Walking Beams 9

   3. Design Stresses for All Structural Members Except Walking Beams, Bearing Shafts, and Cranks 10

   4. Design Loads for Walking Beam 10

   5. Maximum Allowable Stress for Walking Beams 11

   6. Other Structural Components 12

   7. Structural Bearing Design 13

   8. Brakes 13

6. Speed Reducer Requirements 14

   1. General 14

   2. Gear Reducers 14

   3. Chain Reducers 36

   4. Components 37

7. Product Identification 41

   1. Beam Pump Structure Nameplate 41

   2. Speed Reducer Nameplate 41

   3. Installation Markings 41

   4. Supplier/Manufacturing Requirements 42

8. Storage and Maintenance 42

   1. Shipping and Handling 42

   2. Lubrication 42

Annex A (informative) API Monogram 43

Annex B (normative) Beam Pumping Unit Designations 47

Annex C (informative) Recommended Data Forms 50

Annex D (informative)Torque Factor on Beam Pumping Units with Rear Mounted Geometry

Class I Lever Systems with Crank Counterbalance 55

Annex E (informative) Torque Factor on Beam Pumping Units with Front Mounted Geometry

Class III Lever Systems with Crank Counterbalance 67

Annex F (informative) Torque Factor on Beam Pumping Units with Front Mounted Geometry

Class III Lever System with Air Counterbalance 76

Contents

Annex G (informative) Torque Factor on Beam Pumping Units with Rear Mounted Geometry

Page

Class I Lever Systems with Phased Crank Counterbalance 83

Annex H (informative) Examples for Calculating Torque Ratings for Pumping Unit Reducers 93

Annex I (informative) System Analysis 101

Annex J (informative) Product Nomenclature 102

Bibliography 103

Figures

1. Walking Beam Elements 11

2. Helical Gear Load Distribution Factor, Cm, for Helical and Herringbone Gears and

   Well-controlled Heat-treating Processes 18

3. Allowable Contact Fatigue Stress for Through Hardened and Tempered Steel Gears Sac for

   Helical and Herringbone Gears 20

4. Allowable Bending Fatigue Stress for Through Hardened and Tempered Steel Gears Sat 21

5. Helical Gear Load Distribution Factor, Km, for Helical and Herringbone Gears 26

6. Allowable Yield Strength Number for Steel and Nodular Iron, Say 30

7. Minimum Effective Case Depth for Flame or Induction Hardened Gears, he 32

8. Acceptable Flame and Induction Hardening Patterns 33

9. Effective Case Depth for Carburized Gears, he 34

10. Minimum Total Case Depth for Nitrided Gears, hc 35

11. Allowable Stress—Shafting 38

12. Beam Pump Structure Nameplate 41

13. Pumping Unit Reducer Nameplate 41

1. Rating Form for Crank Counterbalances 51

2. Pumping Unit Stroke and Torque Factor Form 52

3. Manufacturer's Gear Reducer Datasheet 53

1. Pumping Unit Geometry 56

2. Division of Dynamometer Card by Crank Angle Using Polished Rod Position Data 61

3. Torque Curves Using Torque Factors 64

4. Calculation Sheet—Clockwise Rotation 65

5. Calculation Sheet—Counterclockwise Rotation 66

1. Front Mounted Geometry, Class III Lever System 68

2. Division of Dynamometer Card by Crank Angle Using Polished Rod Position Data 72

3. Torque Curves Using Torque Factors 75

1. Pumping Unit Geometry 77

2. Division of Dynamometer Card by Crank Angle Using Polished Rod Position Data 81

3. Torque Curves Using Torque Factors 82

1. Rear Mounted Geometry, Class I Lever System with Phased Crank Counterbalance 84

2. Division of Dynamometer Card by Crank Angle Using Polished Rod Position Data 88

3. Torque Curves Using Torque Factors 91

4. Net Reducer Torque Calculation Sheet 92

J.1 Beam Pumping Unit Nomenclature 102

Contents

Tables

Page

1. Maximum Allowable Stresses in Pumping Unit Walking Beams of Structural Steel 12

2. Pumping Unit Reducer Sizes and Ratings 15

3. Speeds for Peak Torque Rating for Gear Reducers 15

4. Maximum Allowable Contact Stress Number Sac for Other Than Through Hardened and

   Tempered Steel Gears 19

5. Elastic Coefficient Cp for Gear/Pinion Material Combinations 19

6. Minimum Gear and Pinion Brinell Hardness Combinations for Through Hardened and

   Tempered Steel Gears 20

7. Allowable Bending Fatigue Stress, Sat (for Other Than Through Hardened and Tempered

   Steel Gears) 24

8. Yield Strength Factor, Ky 29

9. Allowable Key Stresses 39

10. Maximum Allowable Tensile Stress, Fasteners 40

B.1 Pumping Unit Designation 48

Introduction

This specification under the jurisdiction of the API Executive Committee on Standardization and was developed with oversight from API Subcommittee 11 on Field Operating Equipment. This specification is intended to give requirements and information to both parties in the design, selection, and manufacture of beam pumping units. Furthermore, this specification addresses the minimum requirements with which the manufacturer is to comply so as to claim conformity with this specification.

Users of this specification should be aware that requirements above those outlined in this specification may be needed for individual applications. This specification is not intended to inhibit a manufacturer from offering, or the user/purchaser from accepting, alternative equipment or engineering solutions. This may be particularly applicable where there is innovative or developing technology. Where an alternative is offered, the manufacturer should identify any variations from this specification and provide details.

Annex A contains information on the application of the API Monogram for those organizations licensed to API Specification 11E. Forms are provided in Annex C for rating of crank counterbalances (Figure C.1) and for recording pumping unit stroke and torque factors (Figure C.2). Recommendations and examples for the calculation and application of torque factors are contained in Annex D to Annex G, and examples for calculating torque ratings for pumping unit reducers are contained in Annex H. Recommendations and considerations for conducting a system analysis are contained in Annex I. Annex J contains an illustration of a typical beam pumping unit and the nomenclature associated with it.

Specification for Pumping Units

1. Scope

   
   

   This specification provides the requirements and guidelines for the design and rating of beam pumping units for use in the petroleum and natural gas industry. Included are all components between the carrier bar and the speed reducer input shaft. This includes the following:

   
   

   1. beam pump structures,

      
      

   2. pumping unit gear reducer, and

      
      

   3. pumping unit chain reducer.

   
   

   Only loads imposed on the structure and/or gear reducer by the polished rod load are considered in this specification.

   
   

   Also included are the requirements for the design and rating of enclosed speed reducers wherein the involute gear tooth designs include helical and herringbone gearing. The rating methods and influences identified in this specification are limited to single and multiple stage designs applied to beam pumping units in which the pitch-line velocity of any stage does not exceed 5000 ft/min and the speed of any shaft does not exceed 3600 rpm.

   
   

   This standard does not cover chemical properties of materials, installation and maintenance of the equipment, beam type counterbalance units, prime movers and power transmission devices outside the gear reducer, or control systems.

   
   

   See Annex A for product is supplied bearing the API Monogram and manufactured at a facility licensed by API.

   
   

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.

API Specification 11B, Specification for Sucker Rods

AGMA 908-B89 1, Geometry Factors for Determining the Pitting Resistance and Bending Strength of Spur, Helical and Herringbone Gear Teeth

AGMA 2001-D04, Fundamental Rating Factors and Calculation Methods for Involute Spur and Helical Gear Teeth

ANSI 2/AGMA 1012-G05, Gear Nomenclature, Definitions of Terms with Symbols

ASME B29.100 3, Precision Power Transmission, Double-Pitch Power Transmission, and Double-Pitch Conveyor Roller Chains, Attachments, and Sprockets—Incorporating ASME B29.1, ASME B29.3, and ASME B29.4

1 American Gear Manufacturers Association, 500 Montgomery Street, Suite 350, Alexandria, Virginia 22314, www.agma.org.

2 American National Standards Institute, 25 West 43rd Street, 4th floor, New York, New York 10036, www.ansi.org.