US3362078A - Method of and apparatus for the drying and heating of gravel and crushed stone - Google Patents

Method of and apparatus for the drying and heating of gravel and crushed stone Download PDF

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Publication number
US3362078A
US3362078A US545160A US54516066A US3362078A US 3362078 A US3362078 A US 3362078A US 545160 A US545160 A US 545160A US 54516066 A US54516066 A US 54516066A US 3362078 A US3362078 A US 3362078A
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United States
Prior art keywords
bath
drying
particles
melt
heating
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Expired - Lifetime
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US545160A
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English (en)
Inventor
Kamper Erich
Gulden Heinrich
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Essener Teerschotter GmbH
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Essener Teerschotter GmbH
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    • E—FIXED CONSTRUCTIONS
    • E01—CONSTRUCTION OF ROADS, RAILWAYS, OR BRIDGES
    • E01C—CONSTRUCTION OF, OR SURFACES FOR, ROADS, SPORTS GROUNDS, OR THE LIKE; MACHINES OR AUXILIARY TOOLS FOR CONSTRUCTION OR REPAIR
    • E01C19/00—Machines, tools or auxiliary devices for preparing or distributing paving materials, for working the placed materials, or for forming, consolidating, or finishing the paving
    • E01C19/02—Machines, tools or auxiliary devices for preparing or distributing paving materials, for working the placed materials, or for forming, consolidating, or finishing the paving for preparing the materials
    • E01C19/05—Crushing, pulverising or disintegrating apparatus; Aggregate screening, cleaning, drying or heating apparatus; Dust-collecting arrangements specially adapted therefor
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F26—DRYING
    • F26B—DRYING SOLID MATERIALS OR OBJECTS BY REMOVING LIQUID THEREFROM
    • F26B17/00—Machines or apparatus for drying materials in loose, plastic, or fluidised form, e.g. granules, staple fibres, with progressive movement
    • F26B17/02—Machines or apparatus for drying materials in loose, plastic, or fluidised form, e.g. granules, staple fibres, with progressive movement with movement performed by belts carrying the materials; with movement performed by belts or elements attached to endless belts or chains propelling the materials over stationary surfaces
    • F26B17/04—Machines or apparatus for drying materials in loose, plastic, or fluidised form, e.g. granules, staple fibres, with progressive movement with movement performed by belts carrying the materials; with movement performed by belts or elements attached to endless belts or chains propelling the materials over stationary surfaces the belts being all horizontal or slightly inclined
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F26—DRYING
    • F26B—DRYING SOLID MATERIALS OR OBJECTS BY REMOVING LIQUID THEREFROM
    • F26B3/00—Drying solid materials or objects by processes involving the application of heat
    • F26B3/18—Drying solid materials or objects by processes involving the application of heat by conduction, i.e. the heat is conveyed from the heat source, e.g. gas flame, to the materials or objects to be dried by direct contact
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F26—DRYING
    • F26B—DRYING SOLID MATERIALS OR OBJECTS BY REMOVING LIQUID THEREFROM
    • F26B3/00—Drying solid materials or objects by processes involving the application of heat
    • F26B3/18—Drying solid materials or objects by processes involving the application of heat by conduction, i.e. the heat is conveyed from the heat source, e.g. gas flame, to the materials or objects to be dried by direct contact
    • F26B3/22—Drying solid materials or objects by processes involving the application of heat by conduction, i.e. the heat is conveyed from the heat source, e.g. gas flame, to the materials or objects to be dried by direct contact the heat source and the materials or objects to be dried being in relative motion, e.g. of vibration

Definitions

  • Our present invention relates to a method of and apparatus for the drying of granular minerals such as crushed stone, gravel and the like and, especially, comminuted minerals adapted to be combined with a bituminous binder in tar road-paving compositions and the like.
  • Still another object of this invention is to provide an improved apparatus for the heating and drying of mineral granules adapted to obviate the aforementioned disadvantages of earlier systems.
  • the melt is composed of one or more relatively low-melting metals which are maintained in a bath at a temperature above the boiling point of water while the mineral granules are conveyed substantially continuously along the surface of this bath relative to the melt or in entrainment therewith from an input side of the melt, at which the granules are deposited upon the surface, to an output side at which the granules are removed.
  • the melt can be a lead-tin alloy having a melting point advantageously below 200 C. (e.g., 67% tin, 33% lead).
  • the heating of the mineral is effected by direct contact with the metal bath upon which the granules float so that a high heattransfer efficiency is obtained.
  • relative displacement of the bath and the granules in accordance with a specific aspect of this invention greatly facilitates the uniformity of the heating.
  • an apparatus for the heating of granular minerals in the manner set forth comprises an open-top pan or trough containing a metallic melt in the manner described, inlet or feed means at one side of the bath for depositing the granular minerals upon the surface thereof, means on another side of the bath for discharging the dried granules, and means for conveying the floating mineral granules along the surface of the bath between the feed means and the discharge means.
  • the granules can be transported along the bath surface by movement relatively thereto or by entrainment with the melt so that the transport or conveying means can include circulating means for establishing a current of the molten metal across the bath from the feed means to the discharge means.
  • Such circulating means may have one or more pumps providing a molten-metal circulation path drawing the melt from the discharge side and returning it to the feed side.
  • the melt remains substantially stationary while endless conveyor means is disposed above the surface and is provided with plates adapted to sweep just slightly above the surface and carry the granules toward the discharge side.
  • the endless conveyor means is so constructed and arranged that there is substantially no movement of the molten mass.
  • the rake plates of the conveyor means depend from one or more belts or chains disposed above the melt to a level just above the surface of the melt and suflicient to engage the granules floating upon this surface.
  • the transport speed is so selected with respect to the temperature of the melt that a complete dnying is effected. It has been found, surprisingly, that under the conditions described there is substantially no adhesion of the molten mass to the solid phase namely, the mineral granules.
  • FIG. 1 is a diagrammatic vertical cross-sectional view through a preferred type of apparatus for carrying out the present invention.
  • FIG. 2 is a fragmentaary longitudinal cross-sectional view through a modified mineral-drying system.
  • FIG. 1 of the drawing we show a particularly advantageous embodiment of an apparatus for the drying of particular minerals with a minimum formation of dust which comprises a trough, pan or other receptacle 2 recharving a molten-metal bath 3 preferably of the lead-tin alloy mentioned above.
  • the bath 3 surmounts a furnace chamber 1 formed by thermally insulating and preferably refractory walls 4 at one end of which is provided an array of gas burners represented at 5.
  • any conventional combustion means e.g., for atomized liquid fuels, powdered-solid fuels or the like
  • any conventional combustion means e.g., for atomized liquid fuels, powdered-solid fuels or the like
  • an outlet 4 is provided in connection with a chimney hood 7 whose duct 7 communicates with a stack or waste-heat recovery system.
  • the combustion gas thus heats the bath by passing along the bottom of the receptacle.
  • feed means represented by a chute adapted to deposit a layer of particulate minerals M upon the surface S of the bath. Since the bath has a specific gravity substantially in excess of the specific gravity of the rock, the mineral particles, granules or chips float upon the surface S and may be conveyed therealong in the direction of arrow D toward an outlet or discharge means 8 at the opposite longitudinal end of the bath.
  • the discharge means 8 is constituted by a ramp lying substantially at the level of surface S and adapted to receive the crushed-rock chips or gravel transported across the surface S.
  • the transport means here includes an endless conveyor 9 carried by a pair of rollers 9a and 9b overlying the surface .S of the metal bath 3 so that a stretch 9' of the conveyor means is substantially parallel to the surface from the inlet means 6 to the discharge means 8.
  • scraper plates of baflles 10 From the endless conveyor 9, there depends scraper plates of baflles 10 which terminate at a level L slightly above the surface S so that these plates can entrain the granules M without material movement of the molten metal to sweep the granules across the surface S of the bath and carry them onto the ramp 3.
  • a motor 9c is provided to drive the conveyor 9 and is provided with speed control means 9d which can be adjusted in accordance with the moisture content of the mineral particles to set the conveyor speed such that complete drying is effected in a single pass of the minerals across the surface of the path 3.
  • speed control means 9d can be adjusted in accordance with the moisture content of the mineral particles to set the conveyor speed such that complete drying is effected in a single pass of the minerals across the surface of the path 3.
  • the direct contact of the particles with the liquid metal ensures a high rate of heat transfer to the latter and thus a rapid drying of the thin layer of mineral particles disposed upon the surface of the bath.
  • the trough 22 containing the bath 23 of molten metal is again disposed above a furnace chamber 21 but the transport of the mineral particles M from the inlet chute 26 to the outlet ramp 28 is effected by a stream of molten metal.
  • a circulating pump 29c is provided in a circulationpipe system 29 whose inlet 29a is disposed under a perforated collecting plate 291) and whose outlet 29c is disposed substantially at the level of surface S of the bath at the opposite end thereof.
  • the pumping action of the circulating means causes a surface current of molten metal (represented by arrow D) to convey the particles M across the surface S to the collecting plate 2% at which the liquid is separated from the mineral particles which proceed along the discharge ramp 28, the liquid being recirculated to the mouth 29c of the recirculating means.
  • a method of drying particulate stone without loss of fine fractions and without development of dust which comprises the steps of: heating a bath of molten lead-tin alloy having a melting point greater than the boiling point of water and less than 200 C. and a specific gravity greater than that of the stone; depositing the stone particles in a thin layer upon the surface of said bath at a temperature above the boiling point of water whereby said stone floats upon said bath; transporting said particles across said surface from an inlet side to a discharge side of the bath at a rate such that said particles remain upon said surface for a time sufficient to effect a substantially complete drying of the particles and thereafter removing said particles from said melt.
  • An apparatus for the drying of particulate minerals comprising: receptacle means for retaining a hot liquid bath having a specific gravity in excess of that of the mineral and a free upper surface; inlet means at one side of said bath for depositing a thin layer of particles of said mineral upon said surface; discharge means at another side of said bath for removing dried mineral particles from said surface; and transport means for displacing said particles along said surface from said inlet means to said discharge means, said transport means including liquid-circulating means for generating a current of liquid of limited depth only across the surface of said bath entraining said particles from said inlet means to said outlet means.

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  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Microbiology (AREA)
  • Architecture (AREA)
  • Civil Engineering (AREA)
  • Structural Engineering (AREA)
  • Manufacture And Refinement Of Metals (AREA)
  • Drying Of Solid Materials (AREA)
US545160A 1965-04-23 1966-04-25 Method of and apparatus for the drying and heating of gravel and crushed stone Expired - Lifetime US3362078A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
DEE0029169 1965-04-23

Publications (1)

Publication Number Publication Date
US3362078A true US3362078A (en) 1968-01-09

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US545160A Expired - Lifetime US3362078A (en) 1965-04-23 1966-04-25 Method of and apparatus for the drying and heating of gravel and crushed stone

Country Status (5)

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US (1) US3362078A (xx)
BE (1) BE679876A (xx)
FR (1) FR1476368A (xx)
GB (1) GB1106855A (xx)
NL (1) NL6605319A (xx)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3968013A (en) * 1974-09-12 1976-07-06 Hollis Engineering, Inc. System for cleaning work pieces with solvent
US3996949A (en) * 1974-09-12 1976-12-14 Hollis Engineering, Inc. Solvent cleaning system

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN111578673A (zh) * 2020-06-09 2020-08-25 济源市阳光兔业科技有限公司 一种用于兔饲料生产的烘干设备

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1520080A (en) * 1922-03-10 1924-12-23 Gulf Refining Co Recovering aluminum chloride
US1801263A (en) * 1929-03-30 1931-04-21 Algernon R Burnette Method of heating for drying, baking, distilling, and the like
US1803767A (en) * 1927-01-08 1931-05-05 George W O'keeffe Drying

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1520080A (en) * 1922-03-10 1924-12-23 Gulf Refining Co Recovering aluminum chloride
US1803767A (en) * 1927-01-08 1931-05-05 George W O'keeffe Drying
US1801263A (en) * 1929-03-30 1931-04-21 Algernon R Burnette Method of heating for drying, baking, distilling, and the like

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3968013A (en) * 1974-09-12 1976-07-06 Hollis Engineering, Inc. System for cleaning work pieces with solvent
US3996949A (en) * 1974-09-12 1976-12-14 Hollis Engineering, Inc. Solvent cleaning system
US4089339A (en) * 1974-09-12 1978-05-16 Hollis Engineering, Inc. Solvent cleaning system

Also Published As

Publication number Publication date
BE679876A (xx) 1966-10-03
FR1476368A (fr) 1967-04-07
GB1106855A (en) 1968-03-20
NL6605319A (xx) 1966-10-24

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