Apparatus and methods for controlling the temperature of exhaust gases in a drum mixer
AssigneeGencor Industries, Inc.
InventorDavid F. Brashears
Life of this patent
Estimating the term…
Abstract
A inclined rotary drum mixer has flights for forming a veiling pattern of particles across the width of the drum for a substantial axial extent. The drum has a burner for flowing hot gases of combustion in heat transfer contact with the particle or aggregate veil. A diverter or interceptor is disposed in the drum for interrupting the cascading or veiling pattern to define a channel for flow of hot combustion gases free of heat transfer contact with the particles of the veiling pattern. By controlling the magnitude of the channel formed by the interceptor or diverter, the average exhaust gas temperature of the exhaust gases may be controlled.
Claims34
Apparatus for mixing, heating and drying solid particles comprising:
- a drum mounted for rotation about an axis and having an inlet for supplying particles into the drum and an outlet for discharging the mixed, heated and dried particles from the drum;
- means for supplying hot gases of combustion for flow in a generally axial direction along the interior of the drum to heat the particles in the drum;
- an exhaust outlet for the hot gases within the drum;
- flighting extending longitudinally within said drum between said inlet and outlet for creating a veil of particles across the interior and along a longitudinally extending region of said drum in response to rotation of the drum about said axis and through which veil the hot gases of combustion flow in heat transfer relation with the particles;
- and
- longitudinally extending means within said drum and in said region for intercepting at least a longitudinal extent of the veil of particles within the drum to define a longitudinally extending channel substantially free of veiling particles such that a portion of the hot gases flowing along the drum bypasses the particle veil and passes through said channel.
Apparatus for mixing, heating and drying solid particles comprising:
- a drum rotatable about a generally longitudinal axis and having an inlet for supplying particles to the drum and an outlet for discharging the mixed, heated and dried particles;
- means for supplying hot gases of combustion for flow along the drum to heat the particles in the drum;
- means for displacing the particles along said drum between said inlet and said outlet;
- an exhaust outlet for the hot gases of combustion within the drum;
- flighting within said drum between said inlet and said outlet and responsive to rotation of said drum for creating a veil of particles within the drum in heat exchange relation with the hot gases flowing along said drum;
- and
- means within said drum for forming a channel through the particle veil substantially free of particles such that a portion of the hot gases flowing along the drum bypasses the particle veil and passes through said channel.
Apparatus for mixing, drying and heating solid particles comprising:
- a rotatable drum having an inlet for supplying particles to the drum and an outlet for discharging the mixed, dried and heated particles;
- means for supplying a stream of hot gases of combustion within the drum for disposition in heat transfer relation to the particles in the drum;
- an exhaust outlet for the hot gases within the drum;
- flighting within said drum for creating a veil of particles within the interior of the drum in response to rotation of the drum and through which veil the hot gases of combustion flow in heat transfer relation with the particles;
- and
- means for variably controlling the proportion of hot gases flowing in said drum in heat exchange relation with said particle veil to the total of the hot gases of combustion disposed within the drum such that the average temperature of the gases exhausting through said outlet can be controlled.
In an apparatus for mixing, heating and drying solid particles in a rotatable drum having flighting within said drum for creating a veil of particles in the interior of the drum and through which veil the hot gases of combustion flow, a method of controlling the exhaust gas temperature from the drum comprising the step of variably controlling the proportion of hot gases flowing in said drum in heat exchange relation with said particle veil to the total of the hot gases of combustion flowing through said drum by intercepting at least a part of the veil of particles within the drum to define a channel substantially free of veiling particles such that a portion of the hot gases flowing along the drum bypasses the particle veil and passes through said channel.
A method of drying aggregate material which comprises:
- scattering the material from an upper wall of an elongate chamber over a predetermined length of the chamber to generate a veil of substantially evenly distributed falling material in an interior space of the chamber and extending in thickness over substantially the predetermined length of the chamber;
- flowing hot drying gases longitudinally of the chamber through the chamber, the hot gases traversing the veil of falling materials for transferring heat energy from the hot gases to the falling materials to dry and heat the materials;
- forming within the length of the veil a channel substantially void of falling material longitudinally of and within the chamber, causing at least some of the hot gases to bypass the veil of falling materials;
- and
- gradually varying the cross-sectional area of the channel to vary the extent to which the hot gases bypass the materials in the veil of falling materials, such bypassing hot gases retaining heat energy for controlling the temperature of gases exhausting from the chamber.
Apparatus for modifying a veil of falling materials, the veil of materials being generated in a drying and heating region of a substantially horizontally disposed elongate drum of a drying and mixing apparatus, within which drum the drying and heating is effected by a stream of hot gases flowing longitudinally of the drum and traversing the length of the veil of falling materials, the apparatus for modifying the veil comprising:
- at least one baffle plate supported within the drying and heating region of said drum and extending at least partially through the veil of falling materials;
- and
- means for supporting the at least one baffle plate for pivotal movement about an axis disposed substantially parallel to the longitudinal axis of the drum, to change the projected area of the baffle plate with respect to the direction of the falling materials in the veil, whereby a pivotal movement of the at least one baffle plate creates a void of material in the veil below said baffle plate.
Apparatus for modifying a veil of falling materials, the veil of materials being generated in a drying and heating region of a substantially horizontally disposed elongate drum of a drying and mixing apparatus, said drying and mixing apparatus comprising means for generating a stream of hot gases to move longitudinally through said drum and through said veil of falling materials for drying and heating said materials and exit from said drum after having transferred heat energy to said materials, the veil modifying apparatus comprising:
- means, extending at least partially through the veil of falling materials, for deflecting materials from their path in the veil upon impingement of such materials with a projected area of said deflecting means, and for generating a channel void of said falling materials behind said projected area of the deflecting means to enable the hot gases traversing the veil of falling materials to flow through said channel without contacting such falling materials;
- and
- means for altering the size of said projected area of said deflecting means to change a cross-sectional area of said channel, thereby correspondingly altering the quantity of hot gases which flow through said channel, whereby heat conduction from said hot gases to said materials become altered as a result of the altered flow of such gases through said channel.
Apparatus for modifying a veil of falling materials generated in a drying and heating region of a substantially horizontally disposed elongate drum of a drying and mixing apparatus, within which drum the drying and heating is effected by a stream of hot gases flowing longitudinally of the drum and traversing the length of the veil of falling materials, the apparatus for modifying the veil comprising:
- at least one baffle plate supported within the drying and heating region of said drum for extending at least partially through the veil of falling materials;
- and
- a support for supporting said at least one baffle plate for pivotal movement about an axis disposed substantially parallel to the longitudinal axis of the drum, for changing the projected area of the baffle plate within and for creating a void below said baffle plate through the veil of falling materials.
Dependencies are inferred from the claim text.