US2684267A - Asphalt pressure injection system and mechanism for asphalt mixing plants - Google Patents

Description

July 20, 1954 w. M. MADSEN 2,684,267 ASPHALT PRESSURE INJECTION SYSTEM AND MECHANISM FOR ASPHMT MIXING PLANTS Filed Dec. 12 ,I 1949 2 Sheets-Sheet l INVENTOR.

`WA LTER M. MADSEN f ATTORNEY w. M. MADSE'N ASPHALT PRESSURE INJECTION SYSTEM AND MECHANISM FOR ASPHALT MIXING PLANTS July 20, 1954 Filed Dec. l2, 1949 '2 Sheets-Sheet 2 INVENToR. WALTER M. MAosEN ATTORNEY Patented July 20, 1954 ASPHALT PRESSURE INJECTION SYSTEM AND MECHANISM FOR ASPHALT MIXING PLANTS Walter M. Madsen, Alhambra, Calif., assignor to Madsen Iron Works, Inc., Huntington Park, Calif., a corporation of California Application December 12, 1949, Serial No. 132,488

7 Claims.

The present invention relates generally to material mixing apparatus such as utilized for mixing of -aggregates and a liquid, and is more particularly concerned with improved means for the injection of the liquid into the aggregate.

More specifically, the present invention has a particular utility in the mixing of road building and paving materials, where a mineral aggregate such as sand, gravel, granite, or rock pieces of various sizes are mixed with a binding material such as a bituminous or asphalt material. In its general aspect, the present invention seeks to provide novel means for adding a predetermined charge of the binding material within a relatively short period of time, and further seeks to inhibit dribble of the binding material into the aggregate when the discharge of binding material is terminated. The dribble of binding material is undesirable since it causes spots or collections of free binding material to fall directly on top of the aggregate and because this may occur at or near the end of the mixing cycle. Thus, the dribbled binding material is not adequately mixed so as to incorporate it uniformly throughout the aggregate mass. When the material containing these spots or collections of free binding material is laid on the roadway, wet spots eventually are formed due to traflic kneading and capillary movement aided by the heat of the sun.

With the foregoing in mind, the present invention has for `one object the provision of improved means in lconnection with mixing apparatus for injecting the binding material, wherein continuously operating pumping means may be utilized for delivering the binding material under pressure, and discharge of the binding material may be controlled without the necessity of having to stop the pumping means.

A further object is to provide in such apparatus, improved means for controlling the discharge of the binding material, which is so arranged that dribble of the binding material will be prevented.

Still another object is to provide improved unitary control means for simultaneously controlling the action of the pumping means for the binding material, vand the shutting off of discharge of the binding material in such a manner as to inhibit dribbling into the aggregatewith which it is mixed.

Still another object is to provide a novel distribution and spray means for directing the binding material into the aggregate of a mixer, such means being so arranged that the spray nozzle may be elevated at the conclusion of the injection period so as to -prevent dribble of binding material into the aggregate.

Further objects of the invention will be brought out in the following -part of the specification, wherein detailed -description is for the purpose of fully disclosing the invention without placing limitations thereon.y

Referring to the drawings, which are for illustrative purposes only:

Fig. 1 i-s a side elevational view of apparatus embodying the present invention, portions. being cut away to disclose certain details of construction;

Fig. 2 is a sectional view of the same, taken substantially on line 2-2 of Fig. 1; and

Fig. 3 is an enlarged detailed section through the binding material distributor pipe, taken substantially on line 3-3 of Fig. 1.

Referring generally to the drawings, the improved apparatus of the present invention comprises gener-ally an aggregate weigh box A supported above a pug mill or mixer B, and a binding agent charge determining and discharge mechanism as generally indicated at C. These elements, together with associated weighing mechanisms and control members are conventionally associated and mounted in a suitable frame structure (not generally shown) to form a unit assemblage which may be handled, shipped, and installed as a part of a complete mixing plant installation.

As shown in Fig. 1, the weigh box A is of conventional construction and in practice is supported `by suitable weighing mechanism (not shown) which permits the weighing of required amounts of aggregate in the weigh box by the operator. The weigh box has a ared bottom which terminates in a discharge opening closed by a suitable gate valve I Il supported at its ends for swinging movement to opened and closed positions on pivots =I I.

The pug mill or mixer B comprises a hollow body I2 which forms a pair of mixing chambers within which parallel shafts I3 and I4 are rotatably mounted. These shafts are each provided with a plurality of mixing paddle assemblies I5 which are spaced along the shafts and project radially therefrom, the assemblies coacting to mix the material deposited into the mixing chambers. The hollow body I2 is open at its top where it is connected with a rectangular collar I6 constructed of chnanel members. The upper side of the collar I6 connects with the lower edge of a dust protective housing I'I of sheet metal construction which surrounds it and..

encloses the lower end of the weigh box A so as to form a substantially enclosed connection between the weigh box and the interior of the mixer B.

The charge determining and discharge mechanism C for binding material which is to be mixed with the aggregate in the mixer B, will now be described. For such purpose, there is provided at one end of the mixer B, a receiving container or bucket |8 for the binding material. This bucket is in the present instance constructed in the form of a hollow cylindrical tank of sunlcient capacity to receive the charge of binding material which is to be injected into the aggregate and mixed therewith in the mixer B1. This bucket is provided at its top with a suspension lug i9 by which it may be connected by a shackle 2D or other suitable connector with a lever 2| forming a part of a weighing mechanism (not shown) for determining the proper amount of charge of binding material in the bucket.

Binding material is supplied to the receiving container or bucket I8 through a supply pipe 22 which connects with a source of supply and containsV a control valve 23 for controlling ow into the bucket.

The measured charge of binding material within the bucket i3 is injected into the aggregate in the mixer B by means of a pump 24 having a driving pulley 25 connected through flexible transmission means 25, such as a belt, witi a driving pulley 2l of an electric motor 28. The pump 24 and its driving motor 23 are mounted upon a suitable base 23 which may be separately supported or form a part of the main frame structure or the unit assemblage.

The inlet side of the pump 24 has an intake suction pipe 30 which. extends into the bucketr I8 and has its inlet end disposed adjacent the bottom oi the bucket.

The pump output is connected to a flange connection 3| with a distribution pipe 32 which is supported in the rectangular collar I and extends horizontally above the mixer B midway between the spaced shafts I3 and |4. This distributor pipe 32 is provided adjacent its end which is connected to the pump with a flexible joint 33 which permits the pipe 32 to be' rotated about its longitudinal axis. The distribution pipe 32 has a plurality of discharge nozzles 34- which are aligned longitudinally of the distributor pipe and spaced apart to form a series of outlets from which binding material delivered under pressure to the distributor pipe is sprayed into the aggregate contained in the mixer B.

In order to facilitate handling or the binding material, the pump 24 and its connections including the distributor pipe 32 are maintained in heated condition by a steam line 35 having an inlet connection 36. This steam line has a looped section 35a which extends into the pump intake suction pipe 33, and after being carried through a suitable steam jacket of the pump 24 passes through a section 35D which extends longitudinally of the distributor pipe 32 to an outlet and connection 3l.

Pumping action of the pump 24 isV controlled byv an air valve 33 having an inlet 39 in com'- munication with atmosphere, and an outlet 43 which connects with the intakesuction pipe 3S pump is thereby broken and although the pump is running, its pumping operation is thus rendered inactive, thus permitting the binding materia-l to be weighed Without danger of its being drawn into the pump and injected prematurely.

After the desired charge of binding material is accumulated in the bucket i8, the pumping action of the pump 24 is activated by closing the air valve 38. The prime of the pump is thereby completed and it will pump the binding material from the bucket IB and deliver it under pressure to the distributor pipe 32, from which it is dischargedinto the mixer B through the nozzles 34. Thisv will continue, of course, until the entire charge of binding material has been injected into the aggregate mixer B.

It will be appreciated that at the end of the injection period, when the pump 24 is again deactivated, the residue of binding material in the distributor pipe 32 would ordinarily continue to dribble through the nozzles 34 into the aggregate to' cause undesirable spots or collections of free binding material as previously discussed. In order to correct and overcome this undesirable condition, the distributor pipe 32 is arranged to be rotated as previously explained. During the injection of the binding material, the distributor pipe 32 is so positioned that the nozzles 34 will be directed downwardly at the bottom of the distributor pipe in the position shown in full lines in Fig. 3. At the conclusion of the injection of binding material, the distributor pipe is rotated by means of a lever 4| to a position which will carry the nozzles 34 through an angle of 90 degrees to a position projecting horizontally above the bottom of the distributor pipe 32, such position being shown in dotted lines. Any residual binding material clinging to the interior wall of the distributor pipe will thus accumulate in the lower portion thereof and dribble through the nozzles will be prevented.

The activation and deactivation of the pumping operation by control of the air valve 3S is coordinated with rotation 0f the distributor pipe 32 for changing the position of the nozzles 34 by means of a connecting linkage including a single actuating lever 42 which may be manipulated by the operator. As shown in Figs. l and 2, the lever 42 is slingably supported on a shaft 43 rotatably supported in frame members i4- 44. Also carried by the shaft 43 is a short lever arm 45 which will swing simultaneously with any swinging movement imparted to the lever 42.

As shown in Fig. 2, the lever 42 is connected with the outer end of lever 4| by means of a connecting link rod 43, and the outermost end of lever arm 45 connected with the outermost end of an actuating lever arm 4'! for the valve 38 by means of a link rod 48.

With the connection as described above, movement of the lever 42 tothe full line position as shown in Fig. 2 operates to rotate the distributor pipe 32 so that the nozzles will be directed downwardly, and at the same time the valve 33 will be actuated to closed position so as to activate the pumping operation. Movement of the lever 42 in a countercl'ockwse direction to dotted line position will rotate the distributor pipe so as to elevate the-nozzles 34 as'previously explained and simultaneously operate to open the valve 38 and deactivate' or render the pumping operation inactive. A simple control' is thus alforded the operator`` for controlling injection of the binding material into the aggregate in the mixer B, without danger of.' prematurely injecting the binder material, and without the formation of spots or collection of free binding material in the aggregate as a result of the dribble from the nozzles which is eliminated in the present invention.

I claim:

1. Means for feeding and distributing a binding material into an aggregate for mixing therewith, comprising: a horizontal distributor pipe for said binding material having a discharge opening, said pipe being positioned above the aggregate with which the binding material is to be mixed and supported for rotational movement to a position in which said opening is directed downwardly for discharging binding material from the pipe bottom onto said aggregate, and another position with the opening directed horizontally 90 degrees from the first position to inhibit dribble of binding material therethrough; a continuously running pump for delivering binding material under pressure to said distributor pipe; means for activating and deactivating said pump with respect to its pumping action; and common actuating means for the pump activating and deactivating means, and for rotating said distributor pipe to vary the position of said opening.

2. Means for feeding and distributing a binding material into an aggregate for mixing therewith, comprising: a horizontal distributor pipe for said binding material having a discharge opening, said pipe being positioned above the aggregate with which the binding material is to be mixed and supported for rotational movement to a position in which said opening is directed downwardly for discharging binding material from the pipe bottom onto said aggregate, and another position with the opening directed horizontally 90 degrees from the rst position to inhibit dribble of binding material therethrough; a continuously running pump for delivering binding material under pressure to said distributor pipe; a valve for connecting and disconnecting the intake of said pump to atmosphere; and means for actuating said valve and rotating said distributor pipe in unison.

3. Means for feeding and distributing a binding material into an aggregate for mixing therewith, comprising: a horizontal distributor pipe for said binding material having a discharge opening, said pipe being positioned above the aggregate with which the binding material is to be mixed and supported for rotational movement to a position in which said opening is adjacent the bottom of the pipe for discharging binding material onto said aggregate, and another position with the opening elevated above the pipe bottom; a pump for delivering a charge of binding material under pressure to said distributor pipe; and means for starting and terminating the pumping action including a coordinating motion transmitting control connection with said pipe, whereby pumping action will start upon movement of said opening to the position adjacent the bottom of the pipe, and terminate the pumping action upon movement to said elevated position.

4. Means for feeding and distributing a binding material into an aggregate for mixing therewith, comprising: a horizontal distributor pipe for said binding material having a discharge opening. said pipe being positioned above the aggregate with which the binding material is to be mixed and supported for rotational movement to a position in which said opening is adjacent the bottom of the pipe for discharging binding material onto said aggregate, and another position with the opening elevated above the pipe bottom; means for delivering a charge of binding material under pressure to said distributor pipe; and means coordinated with the movements of said pipe controlling delivery of said charge.

5. Means for feeding and distributing a binding material into an aggregate for mixing therewith, comprising: a spray pipe through which liquid binding material may be discharged onto said aggregate; a continuously operable pump for delivering a predetermined charge of binding material under pressure to said spray pipe; an air valve connection on the inlet to said pump; and means for actuating said air valve to initiate and terminate the pumping action of the pump, and for inhibiting dribble of binding material onto the aggregate upon termination of the pumping action.

6. Means for feeding and distributing a binding material into an aggregate for mixing therewith, comprising: a spray nozzle supported for movement to a downwardly directed position for discharging -binding material into said aggregate, and an elevated non-dribble position; means for delivering a charge of binding material under pressure to said nozzle; means operable to control start and stop of the delivery of said charge; and means actuated simultaneously with said control for moving said nozzle to one of said positions at the start of a charge delivery, and to its other position at termination of charge delivery.

7. Means for feeding and distributing a binding material into an aggregate for mixing therewith, comprising: spray means through which liquid binding material may be sprayed onto said aggregate; means for measuring a predetermined charge of binding material; a pump for delivering the charge of binding material under pressure to said spray means; and means for simultaneously interrupting the action of said pump and inhibiting dribble of binding material through said spray means.

References Cited in the le of this patent UNITED STATES PATENTS Number Name Date 1,617,673 Dezurik Feb. 15, 1927 1,890,337 Ord Dec. 6, 1932 1,987,243 Madsen Jan. 8, 1935 2,013,360 Paris Sept. 3, 1935 2,081,472 Blood May 25, 1937 2,256,422 Brayer Sept. 16, 1941

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