Pulp & Paper Stock Rotary Lobe Pumps

Define the Stock Reaching the Pump

Identify the pulp source and preparation stage, including dilution, mixing, and screening upstream. Stock chest transfer and process feed may require different operating points; specify the source, destination, and flow range for each duty.

Stock characteristics

Consistency and fiber condition. Provide dry-solids content with its measurement basis, fiber type and length, temperature, and observed flow behavior. Consistency alone does not establish pumpability.

Recycled stock

Fillers and residual contaminants. Describe mineral fillers, grit, and any metal, plastic, or long rejects remaining after preparation and screening.

Stock Chest Feeding, Entrained Air & Startup

Provide the chest level range, pump elevation, inlet dimensions, and mixing arrangement. Review whether stock reaches the inlet consistently during drawdown and after idle periods; a full chest does not by itself establish reliable feeding.

Describe foam, entrained air, and interruptions to liquid supply, with measurements where available. Assess their effect on delivered flow, priming, and seal support for the selected configuration. Review starting load and pressure using the actual stock and pipeline rather than a general consistency or suction-lift limit.

Mineral Fillers, Grit & Wetted Materials

Report filler and grit identity, concentration with its measurement basis, and particle sizes separately from fiber content. Review hard contaminants and upstream removal before selecting passage geometry; staples or other metal rejects should not be treated as ordinary pumpable fiber.

Match wetted metals, rotor coverings, seals, and any available replaceable wear components to the actual stock, additives, and cleaning chemicals at temperature. Include bleaching or other process chemicals where present; pH alone does not establish compatibility. Set inspection intervals using observed wear and duty conditions.

Fiber Bundles, Screening & Maintenance Access

Describe fiber length, bundles, stringy rejects, and any recurring blockage location. Review screening and stock preparation alongside the proposed pump’s passage dimensions; general solids-handling language does not establish that long fibers or rejects will pass.

Check drawings for cover removal, lifting, and access to seals and wear parts. Confirm which maintenance tasks can be completed without disconnecting pipework for the actual installation, including isolation, drainage, and cleaning before opening the pump.