This is a revision of the 2015 edition of the standard. In this edition standard units and equations, graphs, illustrations, and technical requirements were updated and clarified throughout the document. ANSI/HI 3.1-3.5. offers a basic educational overview on rotary pumps, design and application considerations related to the selection of the right rotary pump for a specific industry use as well as the installation, maintenance and operating procedures. The standard addresses seven basic types of rotary pumps:Sliding vanePiston, axialFlexible memberLobeGearCircumferential pistonScrewThis standard applies to industrial/commercial rotary positive displacement pumps. It includes types and nomenclature; definitions; design and application; and installation, operation, and maintenance. It does not include standards on magnetic drives for sealless pumps (see ANSI/HI 4.1-4.6 Sealless, Magnetically Driven Rotary Pumps for Nomenclature, Definitions, Application, Operation, and Test) nor rotary pumps primarily used for fluid power applications. For information on rotary pump tests, see ANSI/HI 3.6 Rotary Pump Tests.A comprehensive overview of features and attributes of rotary pumps is presented in Sections 3.1.1 through 3.1.7.2.2, which contain descriptive material covering the basic technologies highlighted in Figure 3.1. These include a description of each configuration, typical applications, and general operating ranges for commercially available designs for viscosity, flow, and pressure. Operating ranges stated represent only a single hydraulic parameter and do not indicate that all maximum conditions can be met simultaneously. Suppliers should be contacted for such details.