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CA1060278A - Production of aggregate material coated with bituminous binder - Google Patents

Production of aggregate material coated with bituminous binder

Info

Publication number
CA1060278A
CA1060278A CA245,552A CA245552A CA1060278A CA 1060278 A CA1060278 A CA 1060278A CA 245552 A CA245552 A CA 245552A CA 1060278 A CA1060278 A CA 1060278A
Authority
CA
Canada
Prior art keywords
region
mixing
chamber
aggregate
aggregate material
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired
Application number
CA245,552A
Other languages
French (fr)
Inventor
Dennis Jervis
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Frederick Parker Ltd
Original Assignee
Frederick Parker Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Frederick Parker Ltd filed Critical Frederick Parker Ltd
Application granted granted Critical
Publication of CA1060278A publication Critical patent/CA1060278A/en
Expired legal-status Critical Current

Links

Classifications

    • EFIXED CONSTRUCTIONS
    • E01CONSTRUCTION OF ROADS, RAILWAYS, OR BRIDGES
    • E01CCONSTRUCTION OF, OR SURFACES FOR, ROADS, SPORTS GROUNDS, OR THE LIKE; MACHINES OR AUXILIARY TOOLS FOR CONSTRUCTION OR REPAIR
    • E01C19/00Machines, tools or auxiliary devices for preparing or distributing paving materials, for working the placed materials, or for forming, consolidating, or finishing the paving
    • E01C19/02Machines, 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
    • E01C19/10Apparatus or plants for premixing or precoating aggregate or fillers with non-hydraulic binders, e.g. with bitumen, with resins, i.e. producing mixtures or coating aggregates otherwise than by penetrating or surface dressing; Apparatus for premixing non-hydraulic mixtures prior to placing or for reconditioning salvaged non-hydraulic compositions
    • E01C19/1013Plant characterised by the mode of operation or the construction of the mixing apparatus; Mixing apparatus
    • E01C19/1027Mixing in a rotary receptacle
    • E01C19/1031Mixing in a rotary receptacle the mixture being discharged continuously
    • EFIXED CONSTRUCTIONS
    • E01CONSTRUCTION OF ROADS, RAILWAYS, OR BRIDGES
    • E01CCONSTRUCTION OF, OR SURFACES FOR, ROADS, SPORTS GROUNDS, OR THE LIKE; MACHINES OR AUXILIARY TOOLS FOR CONSTRUCTION OR REPAIR
    • E01C19/00Machines, tools or auxiliary devices for preparing or distributing paving materials, for working the placed materials, or for forming, consolidating, or finishing the paving
    • E01C19/02Machines, 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
    • E01C19/10Apparatus or plants for premixing or precoating aggregate or fillers with non-hydraulic binders, e.g. with bitumen, with resins, i.e. producing mixtures or coating aggregates otherwise than by penetrating or surface dressing; Apparatus for premixing non-hydraulic mixtures prior to placing or for reconditioning salvaged non-hydraulic compositions
    • E01C19/1013Plant characterised by the mode of operation or the construction of the mixing apparatus; Mixing apparatus
    • E01C19/1027Mixing in a rotary receptacle
    • EFIXED CONSTRUCTIONS
    • E01CONSTRUCTION OF ROADS, RAILWAYS, OR BRIDGES
    • E01CCONSTRUCTION OF, OR SURFACES FOR, ROADS, SPORTS GROUNDS, OR THE LIKE; MACHINES OR AUXILIARY TOOLS FOR CONSTRUCTION OR REPAIR
    • E01C19/00Machines, tools or auxiliary devices for preparing or distributing paving materials, for working the placed materials, or for forming, consolidating, or finishing the paving
    • E01C19/02Machines, 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
    • E01C19/10Apparatus or plants for premixing or precoating aggregate or fillers with non-hydraulic binders, e.g. with bitumen, with resins, i.e. producing mixtures or coating aggregates otherwise than by penetrating or surface dressing; Apparatus for premixing non-hydraulic mixtures prior to placing or for reconditioning salvaged non-hydraulic compositions
    • E01C2019/1081Details not otherwise provided for
    • E01C2019/1095Mixing containers having a parallel flow drum, i.e. the flow of material is parallel to the gas flow

Landscapes

  • Engineering & Computer Science (AREA)
  • Architecture (AREA)
  • Civil Engineering (AREA)
  • Structural Engineering (AREA)
  • Road Paving Machines (AREA)
  • Preparation Of Clay, And Manufacture Of Mixtures Containing Clay Or Cement (AREA)

Abstract

Abstract of the Invention:

The invention relates to a process for coating aggregate material with .epsilon. bituminous binder for use in the construction of roadways and the like. In order to minimise the formation of dust, the material is first mixed in an undried, unheated condition with cohesion-promoting additives, such as lime or asbestos, then transferred into a region where it is subjected to the passage of heated gases flowing in the same direction as the material, which is then brought into contact with liquefied bitumen.

Description

- ~06~)Z7~3 The invention is concerned with improvements in or relating to the production of coated aggregate material, in which suitably graded aggregate material is mixed with a bituminous binder to produce, for example, roadstone mixture.

In the production of coated aggregate material there arises the problem of dust formation and steps are necessary to prevent undue atmospheric pollution. It is considered essential that the uncoated aggregate material be in a heated condition when the liquefied bituminous binder is applied, to prevent premature solidification of the binder and consequent inadequate mixing and coating.

However, the heating of the uncoated material causes fine particles adhering to the aggregate to-be separated off and picked up by the stream of heating gases. Removal of the dust from the waste gas, preferably for return to the mixing stage, is expensive, involving costly filters, cyclones, washing apparatus, precipitators and the like. Frequently the control of dust emission to a level below the permitted 20 maximum represents as large a proportion of the production costs as do the actual heating and mixing operations.

It is an object of the present invention to provide a process for the production of coated aggregate materials which minimises the above disadvantages.

According to the invention there is provided a process for the production of aggregate material coated with a bituminous binder which comprises the steps of a) passing the aggregate material successively through first~ second and third mixing regions, b) mixing the undried unheated aggregate material
-2-~060278 with suitable cohesion-promoting additives in said first mixing region, c) subjecting the mixture to the heating effect of heated gases flowing in the same dir~ction as the mixture in said second mixing region, and d) adding a liquefied bituminous binder to the heated aggregate/additive mixture in said third mixing region to coat particles comprising said ag~regate material.

Conveniently, where the uncoated aggregate material is too dry to provide sufficient water vapour in the second and third mixing regions to prevent degradation of the material, water may be added to the material at the first mixing region. :

The invention further provides apparatus suitable for use in carrying out the above states process, comprising a cylindrical mixing chamber adapted to rotate about a lengthwise extending axis thereof, means to facilitate mixing of materials charged to said chamber as said materials pass 20 therethrough in a path parallel to said axis, the chamber having material input means and discharge means, a first mixing region at one end thereof in the vicinity of said input means, a second mixing region at an intermediate locality of the chamber and a third mixing region at an opposite end of the chamber in the vicinity of said discharge means, and being provided with a burner device arranged to direct a flow of heating gases from said second region towards said third region, the chamber being further provided with a partition wall partially dividing said first region from said second .~

6~Z78 region, and delivery means to supply liquefied binder to the third region thereof.

~ dvantageously the position of the burner device is adjustable within said second region. ~imilarly the position o~ the partition wall is adjustable to vary the effective lengthwise dimensions of the first and second regions according to operating conditions and it is convenient if the burner device and the partition wall are interconnected by suitable mounting arr~ngements for simultaneous adjustment.

~ he burner device may conveniently comprise a single burner or a plurality of burner units.

Conveniently the input means of the chamber provides facilities for charging aggregate material and cohesion-promoting additives separately, water being added to the additive charge if required.

It is also advantageous to provide for adjusting of the position of the binder delivery means within the third region of the chamber.

~here will now be described with re~erence to the accompanying drawing an apparatus according to the invention arranged to carry out the process according to the invention.
It will be understood that the description is given by way of example only and not by way of limitation of the invention.

~ he drawing shows a diagrammatic representation of the operating features of the apparatus.

: 4 :

.
': ' ' 106~278 ~ he apparatus comprises a mixing chamber 2 including a cylindrical wall 4 moun-ted for rotation abou-t a lengthwise extending axis by drive means (not shown). ~he chamber is mounted in a slightly inclined position, the angle of inclination being variable from the hori~ontal to assist in the passage of charged materials therethrough in a direction from left to right as viewed in the drawing. Mixing of the material during its passage is enhanced by the presence of lifters 6 on the interior of the wall 4, Input means at one end of the chamber comprise a chute 8 for directing undried aggregate material from a conveyor 10 into a first mixing region A of the chamber, together with cohesion-promoting additives, lime, asbestos, slate flour, or other substances such as resins and polymers selected according to the conditions of operation. Such additives are charged into the region A of the chamber from a pipe 12 together with the re~uired quantity of water.

~ he chute 8 enters the chamber through a stationary end wall 14. A burner device 16 is also mounted in the end wall 14 for limited sliding lengthwise movement. ~he device 16 is arranged to project into the chamber along the axis of rotation.

Also mounted in the end wall 14 is a delivery pipe 18 for liquefied bituminous binder. ~his pipe also extends into the chamber being arranged to lie parallel to the burner. ~he pipe 18 is also mounted for limited sliding movement in a lengthwise direction, but the most leftward (withdrawn) position of its discharge end 19 is arranged to lie to the right of the most fully extended position of the burner
3 device 16 (as viewed in thedrawing) by a dis-tance : 5 :

106~)Z78 corresponding -to the minimum length of a second mixing region B.

hrranged ~etween the regions A and B is a parti-tion wall 20 which partly divides the chamber at this poin-t. '~he wall is disc-shaped c~nd securely mounted upon the leading end portion of the burner device 16, leaving an annular passage around the periphery of the wall 20.

~ he second mixing region B is that portion of the chamber between the partition wall 20 and the discharge end 19 of the pipe 18. ~he region between the pipe end 19 and the discharge end of the chamber is the third mixing region.
A flue 22 takes off the hot gases and exhaust products and a discharge chute 24 carries away the coated aggregate material.

~ he operation of the apparatus described in this example is as follows.

Undried, uncoated aggregate material is conveyed into the chute 8 together with the required amount of additive, in the present example, lime, being about 2% of the dry weight of aggregate, which may be what is termed "base mix"
i.e. an intermediate layer in the construction of a road. If necessary, water will be added to the additives which are charged to the chamber 2 in the form of a slurry or dispersion. ~he material and additives which are both at ambient temperature are mixed together in the first mixing region, A, of the rotating chamber. ~he lifters 6 aid the thoroughness of this mixing.

~ he angle at which the chamber is tilted and the ingress of further material causes the already mixed material to move : 6 ~ 06~78 to the right a~d enter the second mixing region, B, through -the annular passage around the periphery of the partition wall 20.

Here the mixing action continues, but the mixed material is now subjected to the radia.ted heat a~d the heated gases issuing from the burner device 16. '~his causes the temperature of the material to rise to between 50 - 80C and for a considerable degree of drying-out to occur.

Further progress in a direction to the right of the drawing brings the new dried material into the third mixing region and into contact with liquefied bituminous binder supplied through the pipe 18. r~he binder has been liquefied by suitable heating means (not shown) not forming part of the present invention~

q'he burner device is regulated to maintain the material temperature at approximately an even level until the coated material is discharged by the chute 24, the gases and exhaust products leaving through the flue 22.

Where the aggregate material to be coated is, for example, a top or we æ ing surface quality, the material is charged at ambient tempera-ture as before. r~he mixing takes place as before, but it will be found advantageous to regulate the burner device to produce a temperature in the material of between 80 - 100C at the discharge end 19 of pipe 18. r~he temperature of the material as it traverses -the third mixing region a will then rise to, for example, 150 - 180~, or a similar temperature appropriate to the materials being used.

Where -the materials used demand a longer mixing time in : 7 :

1060~7~
the region A, i.e. the cold mixing region, the par-tition wall 20 and the burner device 16 will be in a position to the right of their permitted range of movement. In order to give the required amount of drying time before the third region C is reached, it will probably be necessary -to move the pipe 18 towards the right hand end of the chamber. The degree of penetration of the bituminous binder will determine how far the pipe can be positioned at the right hand end of its range to allow for adequate coating.

Alternatively where the materials require a comparatively lengthy drying operation, the burner 16 and the partition 20 may be moved towards the left to bring -the materials into the second mixing region at an earlier stage in their passage throu~h the chamber.

: 8 :

' ' ; : ' ., ' ~

Claims (9)

THE EMBODIMENTS OF THE INVENTION IN WHICH AN EXCLUSIVE
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. A process for the production of aggregate material coated with a bituminous binder comprising the steps of a) passing the aggregate material successively through first, second and third mixing regions, b) mixing the undried unheated aggregate material with suitable cohesion-promoting additives in said first mixing region, c) subjecting the mixture to the heating effect of heated gases flowing in the same direction as the mixture in said second mixing region, and d) adding a liquefied bituminous binder to the heated aggregate/additive mixture in said third mixing region to coat particles comprising said aggregate material.
2. A process according to Claim 1 comprising the further step of adjusting the length of the path of the material through each said mixing region.
3. A process according to Claim 1 wherein provi-sion is made for adding water to the material in the first region.
4. Apparatus for the production of aggregate material coated in a bituminous binder according to the process of claim 1, comprising a cylindrical mixing chamber adapted to rotate about a lengthwise extending axis thereof, means to facilitate mixing of materials charged to said chamber as said materials pass therethrough in a path parallel to said axis, the chamber having material input means and discharge means, a first mixing region at one end thereof in the vicinity of said input means, a second mixing region at an intermediate locality of the chamber and a third mixing region at an opposite end of the chamber in the vicinity of said discharge means, and being provided with a burner device arranged to direct a flow of heating gases from said second region towards said third region, the chamber being further provided with a partition wall partial-ly dividing said first region from said second region, and delivery means to supply liquefied binder to the third region thereof.
5. Apparatus as claimed in Claim 4 wherein the position of the burner device is adjustable.
6. Apparatus as claimed in Claim 4 wherein the position of the partition wall partially dividing the first region from the second region is adjustable to vary the length of the path of the material through the regions.
7. Apparatus as claimed in Claim 4 wherein the burner device comprises a plurality of burner units.
8. Apparatus as claimed in Claim 4 wherein the input means includes means for charging the aggregate mat-erial and the cohesion-promoting additives separately.
9. Apparatus as claimed in Claim 4 wherein the position of binder delivery means within the third region is adjustable.
CA245,552A 1975-02-22 1976-02-11 Production of aggregate material coated with bituminous binder Expired CA1060278A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
GB755675A GB1476097A (en) 1975-02-22 1975-02-22 Production of coated aggregate material

Publications (1)

Publication Number Publication Date
CA1060278A true CA1060278A (en) 1979-08-14

Family

ID=9835395

Family Applications (1)

Application Number Title Priority Date Filing Date
CA245,552A Expired CA1060278A (en) 1975-02-22 1976-02-11 Production of aggregate material coated with bituminous binder

Country Status (4)

Country Link
CA (1) CA1060278A (en)
DE (1) DE2606422A1 (en)
GB (1) GB1476097A (en)
IT (1) IT1055187B (en)

Families Citing this family (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4219278A (en) * 1978-01-23 1980-08-26 Mendenhall Robert Lamar Asphalt-aggregate drum mixing apparatus
FR2429039A1 (en) * 1978-06-21 1980-01-18 Graham Et Associates Pty Ltd K Bituminous aggregate prodn. - using control systems to improve product quality and consistency
US4245915A (en) 1979-02-22 1981-01-20 Bracegirdle P E Apparatus for making asphalt concrete
EP0046827B1 (en) * 1980-08-27 1985-04-03 Paul E. Bracegirdle Process and apparatus for making asphalt concrete
DE3423521A1 (en) * 1984-06-26 1986-01-02 ATS Asphalttechnik und Straßenbaugeräte GmbH & Co KG, 6236 Eschborn Method for preparing and producing an asphalt mix, re-using old asphalt material, and a device for implementing the method
FR2582329B1 (en) * 1985-05-24 1987-08-14 Ermont Sa PROCESS AND DEVICE FOR PRODUCING BITUMINOUS COATED PRODUCTS FROM AGGREGATES CONTAINING A HIGH QUANTITY OF FINES.
GB2343389A (en) * 1998-10-23 2000-05-10 John James Todd Method and apparatus for coating granules
CN104313979A (en) * 2014-09-24 2015-01-28 沈阳北方交通重工有限公司 Regenerated material lifting preheating device for microwave asphalt thermal regeneration mixing station
CN116905313B (en) * 2023-09-12 2023-12-05 福建省铁拓机械股份有限公司 Double-return-stroke internal circulation asphalt mixture drying roller

Also Published As

Publication number Publication date
IT1055187B (en) 1981-12-21
DE2606422A1 (en) 1976-08-26
GB1476097A (en) 1977-06-10

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