Literature

Featured Articles

Product Brochures

Papers

The following index lists papers written by staff members of Walker Process Equipment. These papers are intended to provide a perspective and insight into the features of various types of equipment used in the water and wastewater industry.

General

Circular Collector Mechanisms

Drives for Circular Collector Mechanisms

  • Spur Gear Drives - Plant Profiles of Continuously Operating Drives for over 60 Years:
    Ottawa, Illinois WWTP
    Bellevue, Nebraska WTP, Metropolitan Utilities District
    Flagstaff, Arizona, Lake Mary WTFP
    Omaha, Nebraska, Metropolitan Utilities District Florence WTP
  • Spur Gear Turntable Bearing
    July 2002: This paper discusses the Walker Process® turntable bearing with replaceable raceway insert system component materials, possible modes of failure, L10 Life determination,  abrasive wear, contamination, and lubrication considerations.
  • Circular Collector Hydraulic Drives
    January 2006.  This paper examines collector drives employing hydraulic motors and their benefits and disadvantages compared to more conventional electric motor drives and variable frequency controls.
  • Overturning the Overturning Moment Attributed to Water and Wastewater Collectors
    July 2002.  This paper looks at the thrust and radial loads, and overturning moments applied to collector mechanisms.  A typical sewage primary collector, secondary collector, or thickener seldom if ever sees large overturning moments applied to the mechanism.  The question, ‘Why then are bearing designs for high overturning moments applied to this equipment?’ is considered and some answers proposed.
  • Just How Precise is Your 'Precision Gear'
    July 2002.  This paper questions the level of precision of collector drive gears and bearings lacking a definition of ‘Precision’ by the American National Standards Institute, ANSI,  issued standards such as those by the American Gear Manufacturers Association, AGMA, or the American Bearing Manufacturers Association, ABMA. 
  • Drive Lubrication Related to Maintenance Considerations
    July 2002.  This paper discusses maintenance categories related to lubrication and directed by expected equipment performance, service life, and replacement cost.  The type of lubricants and frequency of relubrication or lubricant change out are discussed in light of preventive and predictive maintenance plans.
  • Condensate Removal Systems
    September 2014: This paper discusses various condensate removal systems for clarifier and thickener drives for water and wastewater circular clarifier mechanisms, compares and discusses several methods used to mitigate water infiltration and condensation, and the effectiveness of each method.
  • Comparison of Clarifier Drives
    March 2000: This paper examines the comparative Precision, Metallurgy and Material Rating of gearing offered by Walker Process Equipment and other manufacturers in the water and wastewater industry. Also discusses, with examples, the corrosion resistance of steel, ASTM A536 Gr. 80-60-03 and ASTM A536 Gr.120-90-02.
  • Lubrication of Clarifier Drives - Why Oil Is Preferred Over Grease
    July 2001: This paper examines issues concerning the lubrication of clarifier drives, why oil should be preferred over grease, how the type of lubricant affects maintenance, removal of condensate and other contaminants and the life of the gearing and bearings.
  • A Brief History of the Walker Process Equipment Spur Gear Drive
    June 2002: This paper examines the history of some of the unique design features built into the Walker Process spur gear drive. Some of the topics examined are: pressure angle, aspect ratio, the split spur gear ring, use of cast iron housings, compliance with ANSI/AGMA and the features of the main bearing.
  • Drive Comparison - Walker Process Equipment Replaceable Wire Races vs. Gothic Arch Combination Gear and Bearings
    February 2003: This paper provides direct comparisons of clarifier drives that utilize replaceable wire races and those that use the gothic arch combination gear and bearings. Within the paper are summaries that compare main bearing design, gear design and quality, housings, corrosion resistance, lubrication, and maintenance.This paper examines issues concerning the lubrication of clarifier drives.
  • Automatic Condensate Removal System
    January 2006: This paper describes the Walker Process Equipment Automatic Condensate Removal System (ACRS) that may be used on Walker Process Spur Gear Drive Mechanisms
  • Four Point Contact Slewing Bearing Lubrication & Maintenance
    May 2006: This paper compares the maintenance and lubrication recommendations of the slewing ring manufacturers and the maintenance and lubrication recommendations of component drive assemblers for slewing rings used in their drives. These recommendations do not agree in many important or critical procedures. References are presented from the manufacturers' literature so that the reader can verify the points at which the manufacturer and the assembler diverge.
  • The Drive for Today - and Many Tomorrows
    Revised April 2008: This paper describes the anthology of the various gear rating criteria which have traditionally been used in our industry, including several revisions to AGMA and ANSI/AGMA standards, and how Walker Process has reacted to fulfillment of total conformance with the latest versions, ANSI/AGMA 2001 (Spur Gears) and 6034 (Worm Gears). This upgrade of materials, quality and production machinery has enabled Walker Process to claim the superior split ductile iron ANSI/AGMA Class Q6 precision gear with replaceable races offered in this industry. Also included is a comparative chart of the features offered by various manufacturers.

Anaerobic Digestion

Rotating Biological Contactors (RBCs)

  • A Discussion about Rotating Biological Contactors (RBCs)
    October 2011: This paper discusses the viability of RBCs as an alternative to other processes BOD removal and Nitrification applications and addresses some of the issues raised by those who are cautious about this technology.

Solids Contact Clarifiers

  • The MC ClariFlow - The Ultimate Upflow Solids Contact Clarifier
    December 1999: This paper describes the newest version of the family of ClariFlow upflow solids contact clarifiers, citing the advanced features which are embodied into the design, why they are a true advancement, and also provides recent installations in varying processes, with contact references.

Grit Removal

  • Rolling Grit - Product User Testimonial
    January 2000: This paper provides a description and testimonial of a Rolling Grit installation at the Fox Metro Water Reclamation District serving Aurora, IL and four surrounding communities.

Archive

On-Farm Biogas Recovery Systems - Plant Profiles