The concept of conveying solids with shaftless spirals has been used in Europe since the 1950's primarily for the agricultural industry. The use of this technology for vertical conveyance has been limited in the United States compared to their use in Europe. However, within the
past few years, shaftless screw conveyors have been increasing considered as a viable option for biosolids cake conveyance. Prior to 1999, the maximum vertical lift for a shaftless screw conveyor in North America was limited to 35 feet. Within the last three years, several large shaftless
screw installations have been installed within the United States. The McAlpine Wastewater Management Facility, City of Las Vegas Water Pollution Control Facility, and Clean Water Services, Durham recently replaced their existing cake conveyance systems with shaftless screw conveyor technology.
Two of these installations have pushed this vertical limit to beyond 45 feet. This paper provides a state-of-the-art look at shaftless screw conveyors, reports on the issues related to this technology, and provides valuable “hands on” design, control, and operating suggestions
that can be used in subsequent projects. In addition, this paper describes some of the unresolved issues currently facing shaftless screw conveyor technology.
Proceedings of the Water Environment Federation is an archive of papers published in the proceedings of the annual Water Environment Federation® Technical Exhibition and Conference (WEFTEC® ) and specialty conferences held since the year 2000. These proceedings are not peer reviewed. WEF Members: Sign in (right panel) with your IngentaConnect user name and password to receive complimentary access.