Counterflow drum mixer for making asphaltic concrete and methods of operation
US5538340A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Dec 14, 1993 |
| Grant date | Jul 23, 1996 |
| Priority date | — |
| Expiry date | Dec 14, 2013 |
Classification
- Technology area (CPC E)Fixed Constructions
- CPC primaryE01C2019/109
- WIPO fieldCivil engineering
- WIPO sectorOther fields
Abstract
An inclined counterflow rotating drum mixer has a burner head intermediate an aggregate inlet at one end of the drum and an asphaltic concrete discharge at the opposite end of the drum. A fan supplies secondary air to the burner through a motive tube having an opening in communication with a mixing chamber between the burner head and the discharge end of the drum to aspirate gases from the mixing chamber for flow through the burner flame. The aspiration creates a negative pressure in the mixing chamber, causing a reverse flow of a portion of the combustion gases from the dryer chamber into the mixing chamber for preheating RAP input to the mixing chamber. RAP is also preheated by providing a preheat chamber adjacent the flame zone but segregated from direct contact with the flame to preheat the RAP. Hot and dried virgin aggregate is mixed with the RAP in the preheat chamber and valves are provided to prevent gases evolved from the RAP in the preheat chamber from flowing into the drying chamber.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.