摘要:
An apparatus for controlling the angular velocity and slope angle of a hot mix asphalt drum as a function of the temperature gradient across the drum outlet. Uneven gas outlet temperature indicates that the veil of RAP (Recycled Asphalt Pavement) in the drum is insufficient. The veil is increased by increasing drum speed. The complete recycled asphalt pavement hot mix asphalt plant uses uneven gas outlet temperatures to change drum operating parameters.
摘要:
A drum mixer is useful in the continuous production of asphalt paving composition, and has provision for the accurate control of the final temperature of the composition being produced. The drum mixer comprises a fixedly mounted cylindrical sleeve disposed in a generally horizontal orientation, and rotating blades for conveying the heated aggregate longitudinally through the interior of the sleeve. An opening is provided in the side wall portion of the sleeve, and a box-like enclosure covers the opening and mounts a plurality of sensor mounting tubes, so as to permit one or more sensors to be positioned at a location within the enclosure. The enclosure is located where the blades or mixing action in the sleeve will supply a regular flow of the aggregate into the enclosure, and so that the aggregate then slides over the sensors. The sensors are thus subjected to a representative portion of the aggregate, and they are protected from both the radiant heat of the burner and the physical abuse of the mixing action.
摘要:
An asphalt manufacturing assembly (10) is disclosed that includes a rotatable cylindrical dryer drum (11) having an opening (14) in the front (12) for receiving virgin asphalt aggregate and for permitting the exhaust of fumes and an opening (18) in the back (13) for discharging the heated aggregate and for permitting the introduction of air. A burner (41) adjacent the back (13) introduces a flame and heat into the dryer drum (11). A longitudinal air conduit (22) is formed by a stationary annular shroud (20) around the back portion of the dryer drum (11) that extends longitudinally beyond the dryer drum back end (13). The shroud (20) includes two controllable discharge openings (24,25). The assembly (10) further includes a separate rotatable cylindrical mixer drum (51) having a materials inlet (54) for receiving the aggregate discharged from the dryer drum (11), reclaimed asphalt pavement, liquid asphalt and fines and a discharge opening (58) for discharging asphalt. A scavenger fan ( 95) is disposed generally between the two drums (11,51). Each drum (11,51) further includes a plurality of longitudinally and radially projecting paddles (28,32) attached to each's back end (13,53).
摘要:
Method and apparatus for producing mixtures containing bitumen, in which the material to be treated is conveyed by the force of gravity through a slit-type space between two vertically arranged heated surfaces.
摘要:
An asphaltic mix storage system has an improved conveying apparatus including a housing which is upwardly inclined from the horizontal so as to extend from approximately ground level to the top of a storage container. The conveying apparatus also includes a drag-type conveyor in the housing comprising an endless conveyor chain having spaced apart conveying blades carried thereby with the lower edges of the conveying blades in sliding engagement with the lower wall of the housing. The forward faces of the conveying blades and the lower wall of the housing define an acute angle therebetween to prevent carryover of asphaltic mix beyond the discharge chute at the upper end of the apparatus.
摘要:
A closed, pressurized dust return system for introducing aggregate dust into a stream of liquid asphalt is provided. Aggregate dust is dispensed through a valve from a receiving chamber into a mixing housing. The aggregate dust enters the mixing housing at an intermediate location therein. The liquid asphalt is introduced into the mixing housing through a separate conduit at a location thereon above the point of entry of the aggregate dust. The liquid asphalt and the aggregate combine within the mixing housing to form a slurry composition. A heating jacket substantially surrounds the mixing housing and a system for preventing liquid asphalt from backing up into the receiving chamber is also provided. The dust return system is particularly useful in an asphalt plant using a baghouse.
摘要:
An asphalt drum drying and mixing plant capable of using recycled pavement aggregate material includes two interacting drums, each being heated to different temperatures. A first drum is a parallel flow drying and mixing drum. The recycled material is introduced at the intake or feed end of this first drum and dried and heated to a comparatively low temperature in a first region of the first drum. A burner of relatively lower heat generation capacity furnishes heated gases. The recycled material is protected by supplying the gases through a cylindrical combustion chamber within which the fuel is completely burned such that no luminous gases enter the drum and contact the recycled material. A second, adjacent region of the parallel flow drum is the mixing region. The recycled material is transferred to the mixing region with close control over the temperature at which the material enters the mixing region. The parallel flow drum also has an intermediate feed chute through which virgin aggregate material is added. The virgin aggregate is heated in a counterflow drum to a temperature higher than the recycled material and the temperature of the final mix is controlled by changing the temperature of the virgin material. The exhaust from the mixing region is introduced as secondary air into the counterflow drum burner assembly. From the counterflow drum all gases are passed to a cleaning system including a cyclone separator and a baghouse filter. From the cyclone separator and the baghouse filter separated material and fines are routed into the mixing region together with liquid asphalt cement.
摘要:
A process for the fixation of hydrocarbons found in contaminated oily soil. The contaminated oily soil is used as a component in a cold mix asphaltic concrete. The soil is mixed with asphalt roof cuttings containing fibers and mineral aggregate to form a mixture. This mixture is coated with a cold mix emulsion to form an asphaltic concrete. The hydrocarbons do not leach from the set concrete.
摘要:
In a dryer apparatus including an elongated rotatable drum having an input end and an output end, a burner for directing hot gases into the input end of the drum, and an aggregate feed mechanism for supplying aggregate particles into the drum adjacent the input end and for conveying the aggregate particles toward the output end, an assembly adapted to introduce reclaimed asphalt pavement particles into the dryer includes an inner drum for introducing reclaimed asphalt pavement particles into the elongated drum at a position adjacent the output end of the elongated drum and for moving the recycled asphalt pavement particles within the elongated drum in a direction counter to the direction of flow of the hot gases so that the hot gases heat the recycled asphalt pavement particles during travel of the recycled asphalt pavement particles within the inner drum assembly. The inner drum is mounted for rotation with the elongated drum and has an inlet end, an outlet end, and flighting for moving the recycled asphalt pavement along the inner drum from the inlet end toward the outlet end such that recycled asphalt pavement falls from the outlet end of the inner drum into the elongated drum and mixes with aggregate particles which are introduced into the drum adjacent the input end. The particles are heated by the hot gases moving in and around the inner drum as well as by conduction heating carried out via the flighting within the inner drum.
摘要:
A drum mixer is provided for producing an asphaltic composition. The drum mixer utilizes a first heat source located at an intermediate position within the drum mixer for producing a first current of hot gases directed towards the entry end of the drum mixer. The drum mixer also utilizes a second heat source located at the discharge end of the drum mixer for producing a second current of hot gases directed towards the entry end. Virgin aggregate is introduced into the drum mixer at the entry end of the drum mixer and is heated by the first current of hot gases. Recycle material is introduced into a mixing zone within the drum mixer between the first heat source and the discharge end. The heated virgin aggregate combines with the recycle material in the mixing zone and is further heated by the second heat source. Liquid asphalt is mixed with the virgin aggregate and recycle material in the mixing zone and the product is removed from the drum mixer at the discharge end.