Special Purpose Gear Units for Petroleum, Chemical and Gas Industry Services

ANSI/API STANDARD 613

FIFTH EDITION, FEBRUARY 2003 ERRATA, DECEMBER 5, 2005

REAFFIRMED, AUGUST 2007

Special Purpose Gear Units for Petroleum, Chemical and Gas Industry Services

Downstream Segment

ANSI/API STANDARD 613

FIFTH EDITION, FEBRUARY 2003 ERRATA, DECEMBER 5, 2005

REAFFIRMED, AUGUST 2007

SPECIAL NOTES

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Copyright © 2003 American Petroleum Institute

FOREWORD

API publications may be used by anyone desiring to do so. Every effort has been made by the Institute to assure the accuracy and reliability of the data contained in them; however, the Institute makes no representation, warranty, or guarantee in connection with this publication and hereby expressly disclaims any liability or responsibility for loss or damage resulting from its use or for the violation of any federal, state, or municipal regulation with which this publication may conflict.

Suggested revisions are invited and should be submitted to the standardization manager, American Petroleum Institute, 1220 L Street, N.W., Washington, D.C. 20005.

iii

CONTENTS

Page

1. GENERAL 1

   1. Scope 1

   2. Applications 1

   3. Alternative Designs 1

   4. Conflicting Requirements 1

   5. Definition of Terms 1

   6. Reference Publications 3

   7. Standards 3

   8. Units of Measure 3

2. BASIC DESIGN 3

   1. General 3

   2. Rating 5

   3. Casings 8

   4. Casing Connections 10

   5. Gear Elements 11

   6. Dynamics 13

   7. Bearings and Bearing Housings 20

   8. Lubrication 22

   9. Materials 22

   10. Nameplates and Rotation Arrows 23

3. ACCESSORIES 23

   1. General 23

   2. Couplings and Guards 23

   3. Mounting Plates 24

   4. Controls and Instrumentation 25

   5. Piping and Appurtenances 26

   6. Special Tools 26

4. INSPECTION, TESTING, AND PREPARATION FOR SHIPMENT 26

   1. General 26

   2. Inspection 26

   3. Testing 28

   4. Preparation for Shipment 30

5. VENDOR’S DATA 32

   1. General 32

   2. Proposals 32

   3. Contract Data 33

APPENDIX A SPECIAL PURPOSE GEAR UNITS DATA SHEETS 35

APPENDIX B REFERENCES 45

APPENDIX C COUPLINGS FOR HIGH SPEED GEAR UNITS 47

APPENDIX D RATED LOAD CURVES FOR THRUST BEARINGS

WITH STANDARD 6  6 SHOES 49

APPENDIX E MATERIAL SPECIFICATIONS FOR SPECIAL PURPOSE

GEAR UNITS PAGE 53

APPENDIX F VENDOR DRAWING AND DATA REQUIREMENTS 55

APPENDIX G RESIDUAL UNBALANCE WORK SHEETS 61

APPENDIX H GEAR INSPECTION (INFORMATIVE) 73

APPENDIX I INSPECTOR’S CHECKLIST 77

APPENDIX J RATING COMPARISON API 613 VS. AGMA 2101 81

APPENDIX K SHAFT END SIZING METHOD 85

APPENDIX L TYPICAL MOUNTING PLATES 87

Tables

1. Driver Trip Speeds 3

2. Shaft Assembly Combinations 5

3. Minimum Gear Service Factors 6

4. Material Index Numbers and Maximum L/d Ratios 7

5. Allowable Bending Stress Number, Sa 7

6. Minimum Tubing Wall Thickness 9

7. Drain Pipe Sizes 10

8. Pitch Line Velocities 12

9. Casing Vibration Levels 20

10. Maximum Severity of Defects in Castings 27

1. Gear Unit Housings 54

2. Shafts, Pinions, and Gear Wheels 54

3. Fabricated Gears 54

1. Allowable Contact Stress Per API 82

2. Allowable Bending Stress Per API 82

3. AGMA Grade 1 Allowable Stress Numbers 83

Figures

1. Shaft Assembly Designations (for Parallel-shaft, Single-and

   Double-helical One- and Two-stage Speed Increasers and Reducers) 4

2. Shaft Rotation Designations 5

3. Material Index Number, Through Hardened 7

4. Allowable Bending Stress Number, Sa 8

5. Typical Torsiograph Modification 13

6. Undamped Critical Speed Map 15

7A Typical Mode Shapes—SI Units 16

7B Typical Mode Shapes—Customary Units 16

8 Back-to-back Locked-torque Test (Typical) 31

C-1 Couplings for Gear Units 48

1. Rated Load Curves for Thurst Bearings with Standard 6  6 Shoes:

   Outside Diameters from 5 in. – 8 in. 50

2. Rated Load Curves for Thrust Bearings with Standard 6  6 Shoes:

Outside Diameters from 9 in. – 15 in. 51

1. (Blank) Residual Unbalance Work Sheet 63

2. (Blank) Residual Unbalance Polar Plot Work Sheet 64

3. Sample Residual Unbalance Work Sheet for Left Plane 65

4. Sample Residual Unbalance Polar Plot Work Sheet for Left Plane 66

5. Sample Residual Unbalance Work Sheet for Right Plane 67

6. Sample Residual Unbalance Polar Plot Work Sheet for Right Plane 68

7. Work Sheet—Customary 69

8. Polar Plot—Customary 70

9. Work Sheet—SI 71

10. Polar Plot—SI 72

1. Tooth Alignment (Lead) Modification of Helical Pinion 74

2. Profile Modification 75

1. Mounting Plate with Subplates 87

2. Mounting Plate without Subplates 88

Special Purpose Gear Units for Petroleum, Chemical, and Gas Industry Services

1. General

   1. SCOPE

      This standard covers the minimum requirements for spe- cial-purpose, enclosed, precision single- and double-helical one- and two-stage speed increasers and reducers of parallel- shaft design for petroleum, chemical and gas industry ser- vices. This standard is primarily intended for gear units that are in continuous service without installed spare equipment. Gear sets furnished to this standard shall be considered matched sets.

      Note: The purchase of a spare set of gear rotors or a complete gear unit does not mean that the equipment is spared.

      This standard includes related lubricating systems, con- trols, instrumentation, and other auxiliary equipment. This standard is not intended to apply to gear units in general-pur- pose service, which are covered by API Std 677; to gears inte- gral with other equipment, such as integrally geared compressors covered by Std 617 or Std 672; or to gears other than helical.

      Note: A bullet () at the beginning of a 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 data sheets (see Appendix A); otherwise, it should be stated in the quota- tion request or in the order.

      
      

   2. APPLICATIONS

      The following gear-driven applications may be covered by this standard:

      1. Speed increasers, including those for centrifugal compres- sors, axial compressors, blowers, rotary positive displacement compressors, separators, and centrifugal pumps.

      2. Speed reducers, including those for reciprocating com- pressors, rotary positive displacement compressors, centrifugal compressors, centrifugal pumps, extruders, gener- ators, and fans.

      
      

   3. ALTERNATIVE DESIGNS

      The vendor may offer alternative designs. Any exceptions to the standard including, alternate design differences from this standard, shall be clearly stated in the proposal as required by 5.2.1.

      
      

   4. CONFLICTING REQUIREMENTS

      In case of conflict between this standard and the inquiry, the inquiry shall govern. At the time of the order, the order shall govern.

      1

      
      

   5. DEFINITION OF TERMS

      Terms used in this standard are defined in 1.5.1 through 1.5.38.

      1. axially (horizontally) split refers to casing joints that are parallel to the shaft centerline.

      2. The bending stress number (S) corresponds to the likelihood of fatigue cracking at the tooth root filet. If this stress is excessive, it may lead to failure of the gear teeth.

      3. critical speed is a shaft rotational speed at which the rotor bearing support system is in a state of resonance (see 2.6.1).

      4. The use of the word design in any term (such as design horsepower, design pressure, design temperature, or design speed) should be avoided in the purchaser’s specifica- tions. This terminology should be used only by the equipment designer and the manufacturer.

      5. gauss levels refers to the magnetic field level of a component measured with a “Hall effect” probe, with no interference from adjacent magnetic part or structures.

      6. gear refers to either the pinion or the gear wheel.

      7. The gear service factor (SF) is the factor that is applied to the tooth pitting index and the bending stress number, depending on the characteristics of the driver and the driven equipment, to account for differences in potential overload, shock load, and/or continuous oscillatory torque characteristics.

      8. gear unit is the complete power transmission assembly including the housing, gears, and bearings.

      9. gear unit rated power is the maximum power specified by the purchaser on the data sheet and stamped on the nameplate (see 2.2.1).

      10. gear wheel (bull gear) refers to the lowest speed rotor.

      11. A hunting tooth combination exists for mating gears when a tooth on the pinion does not repeat contact with a tooth on the gear wheel until it has contacted all the other gear wheel teeth.

      12. informative element: Describes part of the stan- dard which is provided for information and to assist in the understanding or use of the standard. Compliance with an informative part of the standard is not mandated.

          Note: An appendix may be informative or normative as indicated.

      13. lead modification: A calculated machined devia- tion of the pinion and/or the gear wheel tooth flank from the