API 681 : 1996 : R2010

Section 1 - General
1.1 Scope
1.2 Alternative designs
1.3 Conflicting requirements
1.4 Definition of terms
1.5 References
1.6 Unit conversion
Section 2 - Basic design
2.1 General
2.2 Casings
2.3 Casing connections
2.4 External forces and moments
2.5 Rotating elements
2.6 Mechanical shaft seals
2.7 Dynamics
2.8 Bearings, bearing housings, and lubrication
2.9 Materials
2.10 Nameplate and rotation arrows
Section 3 - System design
3.1 Ring liquid system
3.2 Controls and instrumentation
3.3 Drivers and transmissions
3.4 Couplings and guards
3.5 Belt drives
3.6 Mounting plates
3.7 Piping
3.8 Special tools
Section 4 - Inspection, testing, and preparation for
      shipment
4.1 General
4.2 Inspection
4.3 Testing
4.4 Preparation for shipment
Section 5 - Vendor's data
5.1 General
5.2 Proposals
5.3 Contract data
Appendix A - Liquid ring vacuum pump and compressor
             system data sheets
Appendix B - Liquid ring vacuum pump schematic
Appendix C - Shaft deflection schematic
Appendix D - Liquid ring vacuum pump ring liquid flow
             schematics
Appendix E - Mechanical seal and piping arrangement
             schematics
Appendix F - Material list
Appendix G - Liquid ring vacuum pumps and compressors
             vendor drawing and data requirements
Appendix H - System considerations, operating variables,
             and test performance conversion

This standard defines the minimum requirements for the basic design, inspection, testing, and preparation for shipment of liquid ring vacuum pump and compressor systems for service in the petroleum, chemical, and gas industries.