US2460884A - Art of mixing a plastic mass in a liquid - Google Patents

Description

5 1949' c. n. F. HJORT ETAL 2,460,884

ART OF MIXING A PLASTIC MASS IN A LIQUID Filfid April 5, 1944 2 Sheets-Sheet l .Z'n pen tans Carl [W fiedrur' f/fort, Oscar l zmr fmanueL .farsm,

Qiivrn ey c. a. F. HJORT ETAL ART OF MIXING A PLASTIC MASS IN A LIQUID 2 Sheets-Sheet 2 Filed April 5, 1944 3 &

Patented Feb. 8, 1949' ART OF MIXING A PLASTIC MASS IN A LIQUID Carl Ivar Fredrik Hjort, Djursholm, and Oscar Victor Emanuel Jansa, Nockeby, Sweden Application April 5, 1944, Serial No. 529,694 In Sweden June 19, 1943 8 Claims. (Cl. 259-36) The present invention relates to the art of mixing a plastic mass in a liquid, and it has for its object to provide an efficient mixing method and an apparatus for'carrying the method into effect which may be applied especially where great quantities of plastic material and liquid have to be intimately mixed and the costs of mixing the materials must be kept low.

According to the invention the desired mixture is produced by feeding a string of the plastic mass into a powerful jet or rapid stream of the liquid in such a manner as to cause the jet or stream to tear the string to particles and to bring along the particles thus torn loose according as the string enters into the space of action of the jet or stream.

The novel method may be used to particular advantage on such plastic masses which consist of solid particles held together by a small amount of liquid, for example plastic or moist clay, and it is intended primarily for mixing clay in Water for the purpose of producing a suspension, which may be applied as a binding agent on layers of sand, gravel and stone (macadam) on rods, starting and landing fields for aircraft, open places and the like, or which may be used in the manufacture of cement and porcelain or for other purposes. The method according to the invention may, however, advantageously be used also for mixing such plastic masses as asphalt, resin, pigmented pastes and the like with a thinner, as well as for emulsifying hydrocarbons in a liquid by using forrthe disintegrating jet the desired liquid mixed with a suitable emulsifier.

The invention will now be described more in detail having references to the accompanying drawings, in which Fig. 1 shows schematically in vertical section an embodiment of an apparatus according to the invention for mixing clay with water,

Fig. 2 shows on a larger scale a detail of the mouthpieces for the string of clay and the jet of water,

Fig. 3 shows schematically in side view and partly in section a complete stationary plant for suspending clay in water, whereas Fig. 4 shows the plant according to Fig. 3 in top view.

Referring to drawing Figures 1 and 2, the moist clay which is to be mixed in the water is introduced into a vertical feeding shaft l, which opens sideways into a vertical feeding chamber 2, containing a feeding screw 3 which is driven from a motor or other driving means, not shown. The axial forces acting on the feeding screw 3 are taken up by a combined axial and radial bearing 5 arranged in the detachable cover 4' of the feeding cylinder. The lower portion 6 of the feeding cylinder 2 tapers downwardly, ending with a downwardly directed cylindrical extruding mouthpiece 1, through which the plastic clay is spurted out in the form of a cylindrical string 8. The diameter of the extruding mouthpiece may, by way of example, be of the order of magnitude of 5 centimeters, and the spurting velocity of the string may be about 1 meters per second. The screw 3 is in the nature of a pump for mixing and extruding the plastic under pressure through the constricted mouthpiece I.

Arranged around the opening of the extruding mouthpiece I is a hollow ring 9, which forms a pressure-chamber to which water of a high pressure, for instance a pressure of 10 to 15 kg./cm. or more, is supplied from a pump or other pressure-water source, not shown. The pressurechamber ring 9 is provided on its inside with a slit-shaped downwardly and inwardly directed mouthpiece or nozzle opening l0, having a width of for instance one millimeter and a depth of for instance ten millimeters, through which nozzle water spurts out in the form of a powerful high-velocity jet of conical shape. Said jet strikes symmetrically from all sides on the string of clay 8 emerging from the extruding mouthpiece I and tears the string to particles according as the string emerges from the mouthpiece, said particles being immediately brought along by the water jet while mixing intimately with the water. The mixing ratio between the clay and the water is adjustable, in that the lower portion of the water nozzle l0 consists of an adjustable screw piece II, by the adjustment of which the amount of water may be increased or decreased.

The jet, which now consists of a mixture of water, clay and possibly air, enters the upper vertical portion of a bent pipe I 2, in which the jet is forced to change its direction of movement before it leaves the pipe through the lower vertical portion thereof. Larger particles possibly present in the mixture are deposited on the walls of the pipe, for example at the bends l3 and I4, where they are retained by inwardly projecting spikes or other catching members, in order to be subdivided immediately thereafter into smaller particles under the action of the following masses of liquid, so that the jet which leaves through the lower mouth of the bent pipe l2 will consist of an intimate mixture of water,

line particles of clay. and air. For the purpose of removing the air there is arranged below the outlet opening or the bent pipe l2 serving as a separator for larger particles an air separator in the form of an open vessel ll having evenly bent concave inner walls along which the clay suspension rushes upwardly while giving off the air, iinally passes over the edges of the vessel and drops into a collecting tank II. This air sep arator eliminates air bubbles by reversing the direction or flow oi the dispersion while exposing it to the air. From the latter the clay suspension, which is now relieved of air bubbles. may be pumped or transported in other manner to the place consumption.

In order to facilitate the passage of the plastic mass through the feed shait I liquid may be added to the plastic mass or the mass may be subjected to pressure. If desired, the powerful jet of liquid may be given some other shape than the shape of a conical shell, for instance the shape of a plane or bent disc which strikes the string of plastic materialtransversely of the direction of the string and "cuts the string to particles. The extruding mouthpiece for the string need not necessarily have a round opening nor does it need to be directed downwardly. but it may have an opening shaped in some other manner, for instance shaped as a squar and some other direction, for instance a horizontal direction.

In the embodiment illustrated in Figs. 3 and 4 the extruding mouthpiece for the clay is built together with the nozzle for the liquid toiorm an enclosed jet unit which is shown schematically only at 2!. Into the extruding mouthpiece the clay is pressed by means of a gear wheel pump 2i, positioned vertically above the mouthpiece. said pump being driven by means oia belt and a gearing from a motor 22 the speed of which may be adjustable. To the gear wheel pump 2| the clay is supplied through a vertical feeding-in funnel 23, in which a sieve 24 for removing stones and other larger solid particles is inserted. To enable adjustment oi the amount of clay fed pro unit of-time through the extruding mouthpiece into the enclosed jet of liquid without having to change the speed of the gear wheel pump there is provided a return pipe 26,

which connects the pressure side of the gear wheel pump with its suction side and in which a regulating valve 25 is provided. Pressure liquid enters the nozzle through the pipe 21 from a centrifugal pump 28 which is direct coupled to a motor 29. The mixture of clay and water obtained leaves the mixing apparatus through the outlet pipe 30. Over a three-way valve 3i said pipe may be connected to either one of two pipe branches l2 and 33, which pass vertically up through the bottom of corresponding sedimenting basins 3| and 35, said pipe branches being provided at their mouths each with a deflecting hub 3i and 31 respectively through which the jet of clay-suspension is deflected downwardly towards the underlying basin. Each of the sedimenting basins II and 35 is provided with an overflow 38 or 3! respectively over which the clay-slime, which is now relieved of larger solid particles, flows into a pump pit M. From the latter the clay-suspension is pumped by means of a pump ll to the place of consumption, which may be at a great distance from the clay mixin plant. For the purpose of reducing the wear, the pump ll is preferably provided with waterlubricated bearings, to which clean water is'supplied under a pressure which exceeds the pressureoi the slime of clay.

The two sedimenting basins ll and II are intended to be used alternately, so that when one basin is in use, the other basin may be relieved of its bottom sediments.

The liquid pump 28, which delivers pressure water to the nozzle, is intended in the first instance to be fed with clean water. As shown on the drawing there is, however, also a possibility of ieeding the pump with clay suspension through a pipe 42 which extends from the outlet pipe ll of the apparatus to a three-way valve 44 provided in the suction pipe 43 0f the liquid pump. By suitably adjusting the three-way valve N, a regulation of the consistency of the clay suspension which leaves the apparatus may obviously be obtained within wide limits while maintaining a satisfactory homogeneity of the g0 mixture. Since the pump 28 is thus sometimes fed with slime, it is preferably. just as is the pump ll, provided with bearings which may be r lubricated with water under super pressure.

The pipe 42 may, of course, alternatively be connected over a three-way valve and a branch pipe to that sedimenting basin 34 or 35, which for the moment is in use, or else the pipe may be arranged to such clay suspension from the pump pit ll.

unit 20 there is provided a shut-off valve 45, which renders it possible to press clean water from the pump 28 to the gear wheel pump 2! for flushing and cleaning purposes.

The plant illustrated in Figs. 3 and 4 i intended for stationary use, in that the mouthpieces for clay and water and the various machines are arranged in a frame which is carried by runners 46 for erection on the ground, preferably near the clay mine, the clay suspension produced being pumped from the mixing plant to the place of consumption. It is, however, also conceivable to arrange the apparatus transportable on a motor car or the like. the outlet pipe 30 being then preferably put in direct communication with spreading mouthpieces carried by the car, through which mouthpieces the clay suspension, according as it is produced, is spurted onto the ground while the vehicle is moving.

The invention is, of course, not limited to the embodiments shown, but various modifications are concievable without departing from the idea of the invention. Thus, the arrangements for removing larger solid particles and air from the be of other kinds than those shown on the drawings. when a clayis used. which contains a large percentage of stone and other solid particles, said impurities may be removed in a separate apparatus before the introduction of the clay into the mixing apparatus. In some cases separting means may be entirely dispensed with. Furthermore, there may be used for the shapin of the plastic mass to a string any other kind of shaping arrangement than that shown on the drawings, and in place of a mouthpiece or nozzle which produces a tree jet of liquid, some other arrangement for producing a jet stream of liquid of sufllcient rapidity may be used. Even other modifications are conceivable.

We claim:

1. An apparatus for producing a uniform dispersion of clay in liquid which comprises in combination an extruding mouth piece, means for extruding raw clay through said mouth In the outlet pipe 30 below the disintegrating 4 mixture 01 the plastic mass and the liquid may" piece in the form of a coherent plastic string, means for compressing water under a pressure of the order of at least about to kg./cm.=, nozzle means for forming a concentric high-velocity jet of said water and for directing it transversely against said string of clay in such fashion that a substantially uniform mixture of clay and water is produced, a common housing for said extruding mouth piece and said nozzle provided with an outlet for said mixture, a conduit for receiving said mixture from said outlet and means in said conduit for temporarily retaining any undispersed clay particles.

2. A method of making a dispersion of plastic material, such as moist clay, in a liquid such as water, which comprises feeding a coherent string of the plastic material into a powerful, highvelocity jet of the liquid in such a manner that the jet disintegrates the string to particles and carries along the particles as fast as the string enters the space of action of the jet or stream.

3. An apparatus for mixing a plastic material of the nature of moist clay with a liquid, which comprises a feeding chamber, an extruding mouthpiece forming a constricted exit for said feeding chamber, means for introducing said plastic material into said chamber, means in the nature of a pump mounted in said feeding chamber for compressing said plastic material and for extruding it under pressure through said mouthpiece in the form of a coherent string, a pump having a suction side and a pressure side for compressing a liquid under a pressure of the order of at least 10 to 15 kg./cm.", a nozzle mounted adjacent said mouthpiece, said nozzle being fed by said liquid from the pressure side of said pump and being so constructed and arranged as to direct a high-velocity jet of the liquid transversely against said plastic string in such manner that said string is disintegrated to produce a substantially uniform mixture of plastic and liquid, and a pipe for recycling part of said mixture to the suction side of said pump to be mixed with the liquid passing to said nozzle.

4. An apparatus for mixing a plastic material of the nature of moist clay with a liquid, which comprises a feeding chamber, an extruding mouthpiece forming a constricted exit for said feeding chamber, means for introducing said plastic material into said chamber, a pump having a suction side and a pressure side mounted in said feeding chamber for compressing said plastic material and for extruding it under pressure through said mouthpiece in the form of a coherent string, a valve controlled recycling pipe connecting the suction side with the pressure side of said pump to regulate the rate of extrusion of said plastic material, means for compressing a liquid under a pressure of the order of at least 10 to 15 kg./cm.=, a nozzle mounted adjacent said mouthpiece fed by said liquid and so constructed and arranged as to direct a high-velocity jet of the liquid transversely against said plastic string in such manner that said string is disintegrated to produce a substantially uniform mixture of plastic and liquid.

5. An apparatus for mixing a plastic material of the nature of moist clay with a liquid, which comprises a feeding chamber, an extruding mouthpiece forming a constricted exit for said feeding chamber, means for introducing said plastic material into said chamber, means in the nature of a pump mounted in said feeding chamber for compressing said plastic material and for extruding it under pressure through said constricted mouthpiece in the form of a coherent string, means for compressing a liquid under a pressure of the order of at least 10 to, 15 kg./cm. a nozzle mounted adjacent said mouthpiece fed by said liquid and so constructed and arranged as to direct a highvelocity jet of the liquid transversely against said plastic string in such manner that said string is disintegrated to produce a substantially uniform mixture of plastic and liquid, a common housing enclosing the extruding mouthpiece for the plastic and the nozzle for the liquid, an outlet conduit leading from said housing and a valve for controlling said outlet conduit; said valve being adapted, when closed, to force the liquid to pass backwardly through the extruding means for cleaning purposes.

6. The process of claim 2 wherein said high velocity jet is a concentric jet, the coherent string of plastic being fed into the center of said jet.

7. The process of claim 2 wherein said high velocity water jet is supplied by water under a REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Name Date Arnold Nov. 30, 1897 Dempsey June 19, 1923 Thomson Oct. 15, 1929 Pawling Mar. 1, 1932 Westberg'et al. Apr. 3, 1934 Johnson Nov. 29, 1938 FOREIGN PATENTS Country Date Germany Apr. 3, 1934 France a- July 8, 1937 Number Number

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