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Aug. 2,1938. A. Sommer 2,125,860
PROCESS AND APPARATUS/FOR PRODUCING A PULVERULENT BUILDING MATERIAL
Filed March 24, 1937 2 Sheets-Sheet 1
Aug. 2, 1938. A. Sommer 2,125,860
. PROCESS AND APPARATUS FOR PRODUCING A PULVERULENT BUILDING MATERIAL
Filed March 24, 1937 2 Sheets-Sheet 2.
Patented Aug. 2, 1938 2,125,860
UNITED STATES PATENT OFFICE
PROCESS AND APPARATUS FOR PRODUC-
ING A PULVERULENT BUILDING MATE-
Albert Sommer, Zurich, Switzerland, assignor to
'. the firm "Straba" Strassenbaubedarfs-Ak-
tiengesellschaft, Zurich, Switzerland
Application March 24, 1937, Serial No. 132,729
In Germany July 25, 1936
14 Claims. (Cl. 94—43)
The present invention relates to a process and apparatus for producing a pulverulent building material from a mixture of clouds or mists formed by atpmization of pulverulent and fluid
6 or liquefied constituents.
According to my own atomization process described, in my Reissue Patent #20,119, a pulverulent constituent is atomized in a mixing chamber in form of a mist or cloud and mixed
10 With a mist or cloud of fluid or liquefied constituents, the particles of the different constituents being thereby caused to settle on one another, as a result of which a pulverulent mixture is obtained as final product.
15 To utilize the process for bituminizing a filler (i. e., a pulverulent or fine grain mineral substance) to be adapted for building purposes, particularly for road construction, a relatively large quantity of liquefied constituent, such as
20 bitumen, must be incorporated in the pulverulent mineral substance. This I found entails difficulties, since the liquefied constituent has the tendency to form lumps when precipitated immediately after mixing.
25 This invention, therefore, has for its' object to provide a process and means which will obviate these difficulties and whereby it will be
• possible to more effectively utilize my atomization process in instances when relatively high
30 percentages of fluid or liquefied constituents are employed. This is accomplished by directing a current of air onto the atomized particles while in a state of suspension, which is adapted to grip the aggregates of the mixture at the
35 point of their injection and to carry the mixture through centrifugal dust separators.
This current of air may, when necessary, be cooled, so as to cool the aggregates during the mixing action. In this manner the particles
40 of the mixture before they have time to settle
down, are held in suspension and cooled by the
air current, preferably produced by suction, long
.'• enough to lose their stickiness and are thereby
prevented from conglomerating, rendering the
45 mixture perfectly fit for storing until put to
use, when, by pressure, heating or otherwise, the
binding property of the mixture can be restored,
To carry out my new process I employ an
apparatus which in principle is known but which
50 for the purposes of the present invention has certain novel features.'
With the known apparatuses of this kind the pulverulent substance is injected by a nozzle into a mixing chamber by compressed air, whereby
55 it is atomized into the form of a mist or cloud. At the same time fluid or • liquefied substances are similarly atomized in the mixing. chamber, wherein the different clouds are caused to become intimately mixed with one another, and
60 from Which the final mixture, after settling
down in the chamber, is dropped out through the openings in the bottom of the mixing chamber. ••-.''.
According to this invention, my apparatus comprises in addition to the means hereinbefore '8 mentioned, controllable inlet passages for the substances to be atomized, and means whereby an air current is caused to grip the mixture to hold the'particles thereof in a state of suspension, and to carry off said mixture through 10 suitable centrifugal dust separators in which it is "separated from the air.
The apparatus also comprises suitable cooling means whereby the mixture may be cooled during the mixing period and other •improvements 15 which will be more fully described hereinafter. In the accompanying drawings which form part of this specification and in which similar reference characters denote corresponding parts:
Fig. 1 is a diagrammatic elevation of one em- 20 bodiment of the apparatus used for carrying out my process; ,
Fig. la is a diagrammatic showing of the bitumen heater and pipes;
Pig. 2 is a top plan view thereof; 25
Kg. 3 is an enlarged sectional elevation of the bitumen atomizing nozzle; Pig. 4 is a cross section thereof; Pig. 5 is-a vertical section of a feeding device for the pulverulent constituents; and 30
Pig. 6 is a vertical section thereof at a right angle to Pig. 5.
I denotes a bitumen heater from which leads a pipe 2 into a bitumen pump 3. Prom the latter the bitumen is conveyed through a pipe 4 35 to an intermediate receptacle 5 in which, as will be presently described, through a circulating system the bitumen is maintained at constant tem'perature. Leading from this receptacle is an overflow pipe 6 which is connected to a return 40 pipe.'7 leading into the heater 1. Contrary to the hitherto known construction, the intermediate receptacle is arranged at a higher eleva-, tion than the injection nozzle, so that the bitumen may flow by its own gravity into the 45 nozzle, instead of, as hitherto, being forced down by compressed air which often causes disturbances, i
A pipe 8 leads from the intermediate receptacle 5 into the bitumen atomizing nozzle 10 carried by 50 the nozzle casing 9. This pipe 8 is connected to a mouthpiece 11 of the bitumen atomizing nozzle 10, as will be hereinafter more fully described. I2 is a motor which serves to drive an air compressor 13. An air tube 14 leads from compressor 13 55 through an oil separator 15 into the air heater Iti and a tube 17 leads from said air heater 16 into the nozzle casing 9 and is connected to the mouthpiece 18 of said bitumen atomizing nozzle 10. The bitumen is sucked up by means" of pump 3 '60
'from the bitumen heater ( through pipe 2 and led into the intermediary receptacle 5 through pipe 4. A portion of the bitumen flows through the overflow pipe 6 and the return pipe T back into the
5 bitumen heater I, while another portion thereof flows through pipe 8 to the nozzle 10 in which the atomization is effected.
By using the overflow pipe 6 and the return pipe 7, not only is a continuous circulation of the
10 bitumen afforded, but both the temperature of the latter and the pressure with which it is discharged from the receptacle 5 are held constant. By preheating the air in the air heater 16 the atomization of the bitumen is greatly enhanced.
15 The pulverulent constituent is charged into a funnel-shaped receptacle I9 at the lower end of which is provided a feeder 20, the construction and operation of which will be hereinafter fully described and whereby the pulverulent constttu
20 ent is uniformly fed into a funnel-shaped receptacle 21 mounted below the same, to be passed therefrom to the compressed air nozzle 22. One or more compressed air nozzles 22 carried by the nozzle casing 9 are adapted to atomize the pul
25 verulent constituents discharged from the receptacle 21. The nozzles 10 and 22 for the bitumen and pulverulent substances, respectively, are spaced according to the requirements so that the atoms or minute particles of the atomized pul
** verulent and bituminous substances become Intimately mixed, or settle upon one another. This mixing action also continues in the chamber 23. At the bottom of said chamber are provided a number of suction funnels 24, 24', 24", 24'", from
M which lead suction pipes 25, 25', 25", 25'", into a common pipe 26, which latter communicates through passages 27, 28, with centrifugal or similar dust separators 29, 30, of well known construction.
40 In the present example two dust separators are provided, although the number is.optional, depending upon the size of the plant. In these dust separators the air is separated, In well known manner, from the dust particles of the" mixture •
48 and the latter allowed to sink to and accumulate at the bottom, from which the mixture, through pipes II, 12, and sluices 33, 34, Is discharged into bags 38, 36 (Fig. 1). The separation of the mixture particles from the air cannot be effectively
60 accomplished by means of filters or like separators because of the tendency of the particles to clog therein. Nor are electric separators practical because of the relatively high cost thereof. I have found that the well known centrifugal dust sep
55 arators are most advantageous for the purpose of this process.
The dust separators 29 and 30 may be jacketed for cooling purposes so that the air circulating therethrough may be effectively cooled.
•0 . The air freed from the particles of the mixture enters the conduit 17 communicating with the upper ends of the separators 29 and 30 and which conduit may also be jacketed for cooling-purposes. This conduit 3T is connected to the suction end of
95 a blower 38 which Is adapted to suck up the air and return it to the chamber 23 through a pipe 41 which too may be suitably cooled. This pipe terminates in the mixing chamber 23 at 41 (Fig. 2) close to the point at which the constituents
70 are atomized by their respective nozzles, so that the current of cooled air strongly agitates the clouds. Branching off the conduit 37 is a pipe 42 which communicates with the suction end of a second blower 43 by which the sucked up air is
75 forced through a pipe 44 into another dust sep
arator 45. From the latter the air is then allowed to pass out through an outlet 48. Such particles of the mixture, that may still be present in the air are discharged from said separator 47 through a sluice 48 into the funnel 19 receiving the pul- 5 verulent constituent.
A motor 49 drives the blowers 31 and 43. A motor 50 drives the pump 3 through belt 61 and pulley 52. The motor 50 is operatlvely connected by belt 53 and pulley 54 to a differential gearing 1° 55, which by sprocket gear 66, chain 57 and sprocket gear 58 drives the feeder 20. The shaft T9 of said feeder carries another gear 60, which by chain 61 and sprocket wheel 62 operates the sluice 48. 15
The construction of the bitumen atomizing nozzle 10 is shown in detail in Figs. 3 and 4.
This nozzle substantially comprises a cylindrical casing 63 provided with an inlet mouthpiece 11 for the admission of bitumen, and an inlet mouth- *° piece 18 for the admission of compressed air. Extending longitudinally through said casing is a tubular body 65 in which is borne the needle valve 66 of the nozzle. This tubular body 65 is threadedly mounted in a threaded bore provided at the *• upper end of said casing. The lower end of said body 65 projects through the lower open end of the casing 63. Mounted around the body 65 between mouthpieces II and 18 is a cup-shaped body 67 carrying suitable packing means. The ** upper end of the body 65 is provided with a • headpiece or flange 69 by means of which the same can be screwed up or down within the casing 63, so that, by an adjustment of the annular cross sectional area of the space 70 provided W between the lower end of the casing 63 and that of the tubular body 66, the discharge of air may be controlled. The body 65 can be secured in position within the casing 63 by a nut 71 working on the threaded end of the body 65, The latter 4* Is also provided longitudinally with internal thread in which works the needle valve 66 of the nozzle, which thus can be raised and lowered to vary the annular space 75 between the conical tip 73* of the needle valve 66 and the conical 41 inner wall of body 65. Thus, by adjusting the needle valve 66 longitudinally, the size of the opening through which the bitumen is discharged can be varied. The needle valve 66 is provided, with a serrated head or knob 66* whereby it can 49 be manipulated. Working on said needle is a nut 72 for tightening the same in adjusted position.
The packing, cup 67 is provided with a plurality of narrow silts 73 extending tangentially rela- w tive to the annular channel 74 formed between the body 65 and the walls of the cup 67. The compressed air entering through mouthpiece II passes through the slits 73 provided in said cup 17 into the annular channel 74 (Fig. 4) and 60 thence to the annular discharge passage 71 which surrounds the bitumen discharge passage 75. The silts being arranged tangentially relative to channel 74 Impart to the current a whirlr intc motion, thereby enhancing the atomization w of the bitumen.
• The bitumen admitted through the mouthpiece 11 enters through openings 65* the tubular body 15. The needle valve 66 is provided at its lower part with a plunger-like shoulder 77 in 70 which are formed slots 76 leading into the discharge chamber 71. These slots 76, as will be seen, are biased so as to impart to the bitumen as it is being discharged a twisting motion. The plunger-shaped shoulder 77 also serves to prop- 75