Pumps—Shaft Sealing Systems for Centrifugal and Rotary Pumps

API STANDARD 682 FOURTH EDITION, MAY 2014

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Contents

Page

1. Scope 1

2. Normative References 1

3. Terms, Definitions, and Symbols 3

   1. Terms and Definitions 3

   2. Symbols 12

4. Sealing Systems 13

   1. Seal Categories, Types, and Arrangements 13

   2. Objectives 15

   3. Specifying and/or Purchasing a Sealing System 15

5. General 23

   1. Unit Responsibility 23

   2. Dimensions 23

6. Design Requirements 23

   1. Common Design Requirements (All Categories) 23

   2. Design Requirements (Category-specific) 45

7. Specific Seal Configurations 48

   1. Arrangement 1 Seals 48

   2. Arrangement 2 Seals 49

   3. Arrangement 3 Seals 52

8. Accessories 54

   1. General 54

   2. Piping for Seal Auxiliary Systems 56

   3. Components of Seal Auxiliary Systems (if Specified in Annex G) 59

9. Instrumentation 72

   1. General 72

   2. Temperature-indicating Gauges 72

   3. Thermowells 73

   4. Pressure Indicators 73

   5. Transmitters and Switches 73

   6. Level Indicators 74

   7. Flow Instruments 74

   8. Relief Valves 74

   9. Pressure Control Valves 75

   10. Pressure Amplifiers 75

10. Inspection, Testing, and Preparation for Shipment 75

    1. General 75

    2. Inspection 75

    3. Testing 76

    4. Preparation for Shipment 80

11. Data Transfer 81

    1. General 81

    2. Data Requirement Forms 82

    3. Datasheet 82

    4. Inspector Checklist 82

Contents

Page

Annex A (informative) Recommended Seal Selection Procedure 83

Annex B (informative) Typical Materials and Material Specifications for Seal Chamber and Mechanical

Seal Components 111

Annex C (informative) Mechanical Seals Datasheets 127

Annex D (informative) Seal Codes 132

Annex E (normative) Mechanical Seals Data Requirement Forms 137

Annex F (informative) Technical Tutorials and Illustrative Calculations 140

Annex G (normative) Standard Piping Plans and Auxiliary Hardware 183

Annex H (informative) Inspectors' Checklist for All Seals 230

Annex I (normative) Seal Qualification Testing Protocol 231

Bibliography 254

Figures

1. Seal Configurations 16

2. Arrangement 1: One Seal per Cartridge Assembly 17

3. Arrangement 2: Two Seals per Cartridge Assembly with a Liquid Buffer Fluid 18

4. Arrangement 2: Two Seals per Cartridge Assembly with or Without a Gas Buffer Fluid 19

5. Arrangement 3: Two Seals per Cartridge Assembly with a Liquid Barrier Fluid 20

6. Arrangement 3: Two Seals per Cartridge Assembly with a Gas Barrier Fluid 21

7. Arrangement 1 Type A Seals 22

8. Arrangement 1 Type B Seals 22

9. Arrangement 1 Type C Seals 22

10. Retention of Seal Components in Vacuum Services and Arrangement 3 Inner Seal 25

11. Seal Chamber Types 26

12. Seal Chamber Register Concentricity 29

13. Section Showing Seal Gland Plate Shoulder 29

14. Seal Chamber Face Runout 30

15. Mechanical Seal Piping Connections 34

16. Plastic Plug with Center Tab and Example of Warning Tag 34

17. Seal Chamber/Gland Plate for Vertical Pumps 34

18. Mating Joint Gasket 35

19. Seal Sleeve Runout 36

20. Auxiliary Sleeve Arrangement 38

21. Seal Sleeve Attachment by Shrink Disk 39

22. Seal Sleeve Attachment by Split Ring 40

23. Clamped Faces 40

24. Distributed Flush Systems 47

25. Attachment of Key Drives to Shaft 47

26. Section Showing Containment-Seal Chamber Bushing for 2CW-CS and 2NC-CS Configurations 51

27. Seal Testing Sequence 77

1. Seal Selection Logic 107

2. Group II Seal Arrangement Selection Chart 108

   Contents

   Page

3. Conversion of mg/m3 to ppmv at 25 °C (77 °F) and Atmospheric Pressure 109

4. Temperature Correction Factor for Figure A.3 110

B.1 Relative PV Comparisons for Seal Face Combinations 121

1. Estimated Gas Leakage for 50 mm Shaft at 0.7 bar, Expressed in Normal Liters per Minute 142

2. Estimated Liquid (Water) Leakage for 50 mm Shaft at 2.75 bar, Expressed in Cubic

   Centimeters per Minute 143

3. Illustration of Alternative Vapor Pressure Margin Calculation Options 145

4. Illustration of Vapor Pressure Margin Calculation Methods as Applied to Propane 145

5. Illustration of Balance Ratio Measurement Points 149

6. Gland Plate Model 156

7. System Model. 156

8. Pipe System Friction Curves 157

9. Tubing System Friction Curves 158

10. Circulating Device Performance and System Resistance in Tubing System Curves 160

11. Circulating Device Performance and System Resistance in Pipe System Curves 160

12. Typical Required Flush Flow for Arrangement 3 CW Seals Without Heat Soak Considered and a Pumped Fluid Temperature of 54 °C (130 °F) 161

13. Typical Required Flush Flow for Arrangement 3 CW Seals with Heat Soak Considered and a

    Pumped Fluid Temperature of 176 °C (350 °F) 161

14. Typical Required Flush Flow for Arrangement 3 CW Seals with Heat Soak Considered and a

    Pumped Fluid Temperature of 260 °C (500 °F) 162

15. Typical Required Flush Flow for Arrangement 3CW Seals with Heat Soak Considered and a

    Pumped Fluid Temperature of 371 °C (700 °F) 162

16. Calculation Points for Piping Plan 53A Systems 165

17. Pressure Alarm Without Temperature Bias 169

18. Barrier Liquid Pressure versus Accumulator Gas Volume 170

19. Barrier Liquid Pressure Against Barrier Liquid Volume 171

20. Drive Collar Holding Capability 178

1. Instrument Symbols 184

2. Equipment Symbols 185

3. Standard Seal Piping Plan 01 186

4. Standard Seal Piping Plan 02 187

5. Standard Seal Piping Plan 03 188

6. Standard Seal Piping Plan 11 189

7. Standard Seal Piping Plan 12 190

8. Standard Seal Piping Plan 13 191

9. Standard Seal Piping Plan 14 192

10. Standard Seal Piping Plan 21 193

11. Standard Seal Piping Plan 22 194

12. Standard Seal Piping Plan 23 195

13. Standard Seal Piping Plan 31 197

14. Standard Seal Piping Plan 32 198

15. Standard Seal Piping Plan 41 199

16. Standard Seal Piping Plan 51 200

17. Standard Seal Piping Plan 52 201

    Contents

    Page

18. Standard Seal Piping Plan 53A 203

19. Standard Seal Piping Plan 53B 205

20. Standard Seal Piping Plan 53C 207

21. Standard Seal Piping Plan 54 209

22. Standard Seal Piping Plan 55 210

23. Standard Seal Piping Plan 61 211

24. Standard Seal Piping Plan 62 212

25. Standard Seal Piping Plan 65A 213

26. Standard Seal Piping Plan 65B 214

27. Standard Seal Piping Plan 66A 215

28. Standard Seal Piping Plan 66B 216

29. Standard Seal Piping Plan 71 217

30. Standard Seal Piping Plan 72 218

31. Standard Seal Piping Plan 74 219

32. Standard Seal Piping Plan 75 221

33. Standard Seal Piping Plan 76 223

1. Standard External Barrier/Buffer Fluid Reservoir 225

2. Alternative External Barrier/Buffer Fluid Reservoir. 226

3. Typical Installation of a Piping Plan 23 Circulation System 227

4. Typical Installation of a Barrier/Buffer Fluid Reservoir 228

H.1 Inspectors' Checklist 230

1. Water Test Parameters 244

2. Propane Test Parameters 245

3. Caustic (NaOH) Test Parameters 246

4. Mineral Oil Test Parameters for Applications Between 5 °C and 176 °C (23 °F and 348.8 °F) 247

5. Mineral Oil Test Parameters for Applications Between 176 °C and 400 °C (348.8 °F and 750 °F) 248

6. Seal Manufacturer Qualification Test Procedure 249

7. Seal Manufacturer Qualification Test Procedure for Containment Seals 250

8. Seal Manufacturer Qualification Test Procedure for Gas Barrier Seals 251

9. Mechanical Seal Qualification Test Form (1CW, 2CW-CW, 3CW-FB, 3CW-FF, and 3CW-BB) 252

10. Mechanical Seal Qualification Test Form (2CW-CS, 2NC-CS, 3NC-FF, 3NC-BB, and 3NC-FB) 253

Tables

1. Clearances Between Rotary and Stationary Components 28

2. Symbols and Size for Seal Chamber and Gland Plate Connections 33

3. Minimum Sleeve Thickness in the Area of Component-drive Set Screws 37

4. Minimum Requirements for Auxiliary Piping 57

5. Minimum Pipe Wall Thickness 58

6. Minimum Tubing Wall Thickness 58

7. Conditions Affecting Cooling Water System Design 61

8. Approximate Densities of Materials Found in Process Streams 63

9. Sizing of Bladder Accumulators 66

10. Nameplate for Bladder Accumulator 69

1. R-phrase Grouping Table 105

2. H Statement Grouping Table 106

Contents

Page

1. Materials Standards 112

2. Miscellaneous Materials Specifications 117

3. Typical Temperature Limits for Seal Face Materials 118

4. Typical Temperature Limits for Secondary Seals 122

5. Typical Hardness Range for Selected Secondary Seals 125

1. Example of an Arrangement 1 Mechanical Seal Code 132

2. API 610 Mechanical Seal Code (Obsolete) 135

1. Pipe and Tube Dimensions for System Loss Calculations 157

2. Typical Hardness Ranges for Set Screw Materials 179

3. Typical Hardness Ranges for Pump Shaft Materials 179

4. Estimated Sleeve Axial Loads 179

1. Organization of Qualification Testing 233

2. Qualification Test Fluid and Pumped Fluid Selection Chart 237

3. Seal Qualification Test Parameters 241

Pumps—Shaft Sealing Systems for Centrifugal and Rotary Pumps

1. Scope

   
   

   This standard specifies requirements and gives recommendations for sealing systems for centrifugal and rotary pumps used in the petroleum, natural gas, and chemical industries. See A.1.1 and A.1.2. It is the responsibility of the purchaser or seal vendor to ensure that the selected seal and auxiliaries are suitable for the intended service condition. It is applicable mainly for hazardous, flammable, and/or toxic services where a greater degree of reliability is required for the improvement of equipment availability and the reduction of both emissions to the atmosphere and life-cycle sealing costs. It covers seals for pump shaft diameters from 20 mm (0.75 in.) to 110 mm (4.3 in.).

   
   

   This standard is also applicable to seal spare parts and can be referred to for the upgrading of existing equipment. A classification system for the seal configurations covered by this standard into categories, types, arrangements, and orientations is provided.

   
   

   This standard is referenced normatively in API 610. It is applicable to both new and retrofitted pumps and to pumps other than API 610 pumps (e.g. ASME B73.1, ASME B73.2, and API 676 pumps).

   
   

   This standard might also be referenced by other machinery standards such as other pumps, compressors, and agitators. Users are cautioned that this standard is not specifically written to address all of the potential applications that a purchaser may specify. This is especially true for the size envelope specified for API 682 seals. The purchaser and seal vendor shall mutually agree on the features taken from this standard and used in the application.

   
   

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 Recommended Practice 520 (all parts), Sizing, Selection, and Installation of Pressure-relieving Devices in Refineries

API Standard 526, Flanged Steel Pressure Relief Valves

API Standard 610, Centrifugal Pumps for Petroleum, Petrochemical and Natural Gas Industries

API Standard 614 Lubrication, Shaft-sealing and Control-oil Systems and Auxiliaries for Petroleum, Chemical, and Gas Industry Services

ASME V 1, ASME Boiler and Pressure Vessel Code, Section V, Non-destructive Examination

ASME VIII, ASME Boiler and Pressure Vessel Code, Section VIII, Rules for the Construction of Pressure vessels

ASME IX, ASME Boiler and Pressure Vessel Code, Section IX, Welding and Brazing Qualifications

ASME B1.1, Unified Inch Screw Threads (UN and UNR Thread Form) ASME B1.20.1, Pipe Threads, General Purpose, Inch

ASME B16.11, Forged Fittings, Socket-welding and Threaded

ASME B16.20, Metallic Gaskets for Pipe Flanges—Ring Joint, Spiral-wound, and Jacketed

1 ASME International, 3 Park Avenue, New York, New York 10016-5990, www.asme.org.

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