US2720425A - Spreading devices - Google Patents

Description

Oct. 11, 1955 H. COANDA 2,720,425

SPREADING DEVICES Filed Dec. 18, 1951 4 Sheets-Sheet l INVENTOR HENRI CO ANDA Oct. 11, 1955 H. COANDA SPREADING DEVICES 4 Sheets-Sheet 2 Filed Dec. 18, 1951 FIG.2

IN VENTO R EIHENRI CoHNDR HT'I'DANLY Oct. 11, 1955 H. COANDA 2,720,425

SPREADING DEVICES Filed Dec. 18, 1951 4 Sheets-Sheet 5 FIG. 3

50 60 a g; 60b 63 INVENTOR H ENRI Q0 ANDA Oct. 11, 1955 co 2,720,425

SPREADING DEVICES Filed Dec. 18, 1951 4 Sheets-Sheet 4 INVENTOR HE NR1 CQANOA A? ENE-y United States Patent Ofiice 2,720,425 Patented Oct. 11, 1955 SPREADING DEVICES Henri Coanda, Paris, France, assignor to Ste. Sebac Nouvelle, S. A., Lausanne, Switzerland, a corporation of Switzerland Application December 18, 1951, Serial No. 262,269

Claims priority, application France May 5, 1951 Claims. (Cl. 302-63) The invention relates to improvements in or relating to spreading devices and more specially toan apparatus capable of performing either atomization or pulverization or simultaneously both these operations.

It is an object of the invention to provide a spreading device comprising the application of the physical phenomenon described in my U. S. Patent No. 2,052,869 and hereinafter referred to as the Coanda effect, for carrying along a considerable volume of gas, e. g. air, with the matter to be spread by using a limited amount of gas compressed at a reduced pressure.

It is another object of the invention to provide an apparatus capable of atomizing and/or pulverizing. a liquid and/ or a solid matter. Said apparatus comprises a set of suction and pressure nozzles supplied with gas under pressure and applying said Coanda effect for carrying along an additional amount of gas, said set being, in the preferred embodiment, adjustable in its orientation and capable of vertical displacement.

The Coanda efiect is apparent When a stream of fluid emerges from any container under a certain pressure through a slot, if one of the lips of the slot orifice is extended and recedes continuously from the direction of the axis of said slot i. e. from the direction of the axis of emergence of the fluid through said slot. Under such conditions, the fluid clings to said extended lip and tends to increase its velocity, producing accordingly an underpressure and therefore a suction andxan intake of gas.

As large volumes of gas can be carried along by suction through a system of nozzles utilizing the abovementioned Coanda effect, it is an object of the invention to carry in suspension in said large volumes of gas the particles of liquid or solid matter to. be spread, in order to blow said particles at a chosen distance.

The new apparatus according to the invention essentially comprises:

(a) a source of motive power and a compressor system driven by said source, said compressor system being e. g. of the centrifugal, the axial or the piston type;

(b) a first system of pipes and couplings which may be stationary, telescopic, jointed or adjustable in its orientation about one or several axes, and which can also be flexible;

(c) a set of nozzles supplied with compressed gas by said compressor system through said first system of pipes and couplings;

(d) a container containing the matter to be spread;

(e) means for discharging said matter in an atomized or pulverized form;

(f) means for sucking up the discharged matter;

(g) a second system of pipes and couplings disposed between said means for atomizing and pulverizing and said set of nozzles, said second system being also, in the preferred embodiment, telescopic and/or flexible.

According to the invention said nozzles are of the convergent-divergent type and are provided with annular slots inside the convergent portion thereof, said slots having one lip of their mouth extended in such a manner that said one lip recedes continuously from the direction of exit from the said gaps. The set of nozzles preferably comprises a first nozzle and a larger second nozzle into which said first nozzle discharges. The mutual positions and the relative dimensions of said nozzles are determined according to the particular requirements and the particular liquid or solid matter to be spread.

The means for atomizing or pulverizing the liquids which have subsequently to be carried along bythe suction gas stream through said second system of pipes and couplings preferably comprises a plate or disc rotating in a container through which the gas is sucked by said set of nozzles.

The rotation of the disc can be performed e. g. mechanically or by means of the gas sucked up through said set of nozzles, gas which would then act on appropriate means for imparting to said disc the desired speed of rotation. The liquid to be spread is fed in the vicinity of the center of said rotating disc, is broken into minute droplets, due to the centrifugal force, and is carried away in this state by the gas sucked through the nozzles.

The means for sucking up a pulverized solid matter to be spread may advantageously comprise a Venturi nozzle, the pulverized matter being fed near the throat thereof by said means for discharging said matter mentioned under paragraph e.

The aforesaid and other objects, features and advantages of the invention will be more easily and fully understood from the illustration of the following embodiments of a spreading apparatus according to the invention, being understood that the invention is not restricted to the details of the illustrated and described embodiments but that is susceptible to modifications and adaptations.

In the attached drawings:

Figure l is a diagrammatic general view of an apparatus comprising a compressor system, a set of nozzles, a container with discharging and sucking means, a first and a second system of pipes and couplings;

Figure 2 is a cross-sectional view of said set of nozzles;

Figure 3 is a diagrammatic cross-sectional view of a portion of the spreading apparatus of Fig. 1, i. e. of an embodiment of the container with discharging and sucking up means for atomizing or pulverizing a liquid to be spread;

Figure 4 shows a modification of the device illustrated in Fig. 3;

Figure 5 is a diagrammatic view of a portion of the spreading apparatus of Fig. l, i. e. of an embodiment of the container with discharging and sucking up means for pulverizing a powder to be spread;

Figure 6 shows a modification of the device illustrated in Fig. 5.

The spreading apparatus illustrated in Figure 1 includes a compressor 21 blowing air (air being chosen, in the whole description of the preferred embodiments, as an example of the gas used for the spreading operation) through a telescopic system 22 of pipes or tubes towards a pipe 23 which may rotate, as hereinafter explained, around the axis of the highest tube of said system 22 of pipes. The pipe 23 carries by means of a swivel joint 24 a pipe 25. Leaving pipe 25 air arrives in the convergent- divergent nozzles 27 and 28, the supply to the nozzle 27 taking place through the pipe 26 including a regulator valve 26b.

The air emerges in the nozzle 27 and in the nozzle 28 through special slots which are best shown at 46 and 47 in Figure 2 and will be described hereinafter. The air passing through said slots 46 and 47 draws: along complementary air 29 due to the afore-mentioned Coanda elfect into the nozzle 28 in addition to the air 30 which arrives from the nozzle 27. The mixture leaves at 31.

The reduced pressure produced in the convergent por tion of the nozzle 27 sucks along in turn an amount of air 32 carrying in suspension particles of the matter to be spread and arriving through a flexible hose 33 which is coupled to a telescopic system 34 of pipes emerging out of a container 35 containing the matter to be dispersed and spread. At the bottom of said container 35 are provided openings 35b which allow intake air to arrive in said container 35 and pass in the vicinity of a stirring device diagrammatically shown in Fig. l, and referred to by the numeral 36 which helps maintain a regular supply or delivery of the matter to be spread contained in said container 35. Various embodiments of the container 35 and the stirring device 36 will be described hereinafter, reference being made to Figs. 3, 4, and 6.

A system of cables 37 having chains 40 at the extremity thereof running over pulleys 41 and 42 are provided for performing the orientation of the pipe 23 and accordingly the set of two nozzles 27 and 28 around the vertical axis of the system 22 of pipes. For the vertical displacement of the telescopic system 22, short chains 39 are attached to the ends of the cables 43, the links of said chains 39 being hooked to the body (not shown) which envelopes the fixed compressor 21 the compressed air causing the lifting of the nozzles and the telescopic system 22, said lifting being limited by the attaching of both chains 39 on the body of compressor 21. For the orientation around the horizontal axis of the swivel 24, a rocking lever 38 is provided, said lever being controlled by the cables 43 and the chains 39.

Figure 2, which is a diagrammatic section through the set of nozzles 27 and 28, shows how the compressed air arriving from the ducts 25 and 26 supplies the annular gaps or slots 46 and 47. The extended lip of the mouth of the slot 46 is provided with small surfaces or facets 45 which are flat in longitudinal section, said facets receding continuously from the direction of the axis of emergence of the compressed air through said slots. Said extended lip forms at the same time an inner wall surface for the emergent portion of the convergent-divergent nozzle 28. Air arriving from duct 25 and leaving through gap 46 produces an underpressure along the wall 45 and causes therefore the intake of air according to the arrows 30 and 29. r

In nozzle 27 the phenomenon of inducing additional air, due to the action of the compressed air 48 arriving through pipe 26 and emerging through the circular slot 47 in said nozzle 27, occurs in the same manner and for the same reasons, the extended lip of the mouth of said slot 47 being realized as the extended lip of the mouth of the slot 46, but, instead of pure air, a mass of air 32, in which the particles of the matter to be dispersed and spread are in suspension, is conveyed.

Figure 3 shows a modification of the assembly 35, 35b, 36 of Fig. l, embodying the preferred means for atomizing a liquid to be spread. The plate or disc 49 rotates around its axis 50, its rotation being realized by using the reduced pressure produced in the pipe 59 by the suction in the nozzle 27, said pipe 59 being connected to the pipe 34 of Fig. 1; said reduced pressure produces an intake of air through opening 54; said air is directed by the fixed blades 52 on the turbine blades 51 which are secured to the inferior side of the disc 49.

Any liquid dropping from the reservoir 55, through the vaned pipe 56, on the central zone of the disc 49 will be spread in the direction shown by arrow 57 due to the centrifugal force produced by the rotation of said disc 49. On entering the chamber 53, the air having passed between the blades 52 and 51 meets the liquid having the centrifugal direction 57 and carries along said liquid towards the pipe 59, forming with said liquid a mixture in the space 58 of the chamber 53.

Figure 4 shows a modification of the system for delivering and atomizing the liquid to be spread described hereinabove. Same references refer to similar elements. Said modification comprises two reservoirs 55 and a different driving system for the disc 49, the blades 51 and 52 of Fig. 3 being replaced by a mechanical driving device e. g. a pair of bevel gears 60a and 60]; protected by a sealed casing 62 and receiving the driving force for the rotation of the disc 49, mounted on the same shaft 50 as the gear 60a, by means of a pulley 63 provided on the shaft 61 of the gear 60b, said pulley 63 being driven by the motor (not shown) driving the compressor 21.

Figure 5 is a diagrammatic view of a modification of the assembly 35, 35b and 36 of Fig. 1 embodying means for carrying along a pulverulent or granular matter to be spread.

An annular convergent-divergent system is formed by the elements 64 and 65, the throat of said system being indicated in 66. On the periphery of said throat are provided openings 66b. The concentrical setting of the element 65 relative to the element 64 is realized by means of a rod 70 carried by a yoke 71. The air arriving as shown by the arrows 69 and ascending towards the hose 76 reaches its optimum velocity in said throat 66 and therefore produces an intake of air through the open ings 66b.

A container 67 contains the pulverised or granular matter 68 to be spread, said matter being continuously supplied to the openings 66b by means of the agitator 72 which may be driven by any known means e. g. by the motor (not shown) driving the compressor or by clockwork.

The mixture of air and matter to be spread passes through hose 76 coupled to the hose 33 (of Fig. 1) and arrives to the nozzles 27 and 28 designed to spread said mixture.

Figure 6 shows a modification of the embodiment shown on Fig. 5, modification in which the means for carrying along a pulverulent or granular matter comprise a convergent duct 64 in front of which is provided an endless belt 73 having perforations 75. Said belt 73 is driven by, and moves over, rollers 74. A stirring device 72 is advantageously driven by one of said rollers 74 and stirs the pulverulent matter 68 of the container 67 in order to control the supply of said matter. Air arriving under the belt 73 passes through the perforations 75 as shown by the arrows 69 and carries along the matter 68 which arrives and is spread on the belt 73. The amount of matter which can not be carried along is stopped by the air which penetrates through the convergent duct 75b and the mixture of air and matter leaves by the hose 76 and reaches through the hose 33 the nozzles 27 and 28 which will spread said mixture, the sucking of air through 75b and through the perforations 75 being performed by the suction in the nozzles 27 and 28 due to the Coanda effect.

The apparatus according to the invention is particularly suitable for realizing a pulverisation and/or an atomization of matters used in agriculture, horticulture, forestry and in the treatment of animals but it may also be used for other purposes.

The invention is not restricted to the specific illustrated embodiment, but is subject to modifications and adaptations which will occur to those skilled in the art, and it should be understood that protection is sought for the invention as covered by the spirit and the language of the attached claims.

What I claim is:

l. A spreading device comprising in combination a source of compressed gas, a series of nozzles in axial alignment with and spaced from one another, each nozzle in said series comprising an inlet end, a convergent portion, a divergent portion and a discharge end, and having a circular slot in said convergent portion, means for delivering compressed gas from said source to said circular slot, said gas flowing through said slot into the nozzle, said slot having in an axial section through the nozzle an extended lip which continually recedes from the direction of emergence of said compressed gas through said circular slot, a container for the matter to be spread,

ra a

means for discharging said matter in a finely divided form and means for delivering said finely divided matter from said discharge means to the inlet end of the first of said series of nozzles.

2. A spreading device comprising in combination a source of compressed gas, a series of nozzles in axial alignment with and spaced from one another, each nozzle in said series comprising an inlet end, a convergent portion, a divergent portion and a discharge end, and having a circular slot in said convergent portion, means for delivering compressed gas from said source to said circular slot, said gas flowing through said slot into the nozzle, said slot having an extended annular lip which comprises, in an axial section through the respective nozzle, a series of straight segments progressively receding from the direction of emergence of said compressed gas through said circular slot, whereby gas flowing through said slot tends to cling to said extended lip and to increase its velocity, a container for the matter to be spread, means for discharging said matter in a finely divided form and means for delivering said finely divided matter from said discharge means to the inlet end of the first of said series of nozzles.

3. In a spreading device comprising a source of compressed gas and a container for receiving the matter to be spread, a first nozzle and a larger second nozzle, each one of said nozzles comprising a convergent portion and divergent portion, said second nozzle being disposed in the alignment of said first nozzle and said convergent portion of said second nozzle following said divergent portion of said first nozzle and spaced at a distance therefrom, said convergent portion of said first nozzle and of said second nozzle being provided with a circular slot having in an axial section through said first and second nozzles an extended lip continuonsly receding from the axis of said circular slot, a first system of pipes for delivering said compressed gas to each said circular slot of said first nozzle and said second nozzle, means for discharging said matter to be spread in a finely divided form and cooperating with said container, suction means connected with said container, and a hose connecting said convergent portion of said first nozzle with said suction means.

4. A spreading device for liquid matter comprising in combination a source of compressed gas; at least one container for said liquid matter; a set of aligned and spaced nozzles, each nozzle in said set comprising a convergent portion, a divergent portion and a circular slot in said convergent portion, said slot having in an axial section through said nozzle an extended lip continuously receding from the axis of emergence of said compressed gas through said circular slot; a first system of pipes and couplings for delivering said compressed gas to each said circular slot; a vertical shaft; a housing having the general form of a body of revolution around said shaft; a horizontal plate secured to said shaft and disposed in said housing, said plate comprising an inferior side and a superior side; a first opening in said housing and forming an intake for gas; a second opening in said housing, said plate being disposed between said first opening and said second opening; a second system of pipes and couplings connecting said second opening with said convergent portion of one of said nozzles disposed at one extremity of said set; means for producing the rotation of said shaft; and delivery means delivering said liquid matter from said container on the superior side of said plate in the vicinity of the center thereof.

5. A spreading device as in claim 4 in which said inferior side of said plate carries a first set of blades and in which said housing carries a second set of blades cooperating with said first set of blades, said first opening in said housing being provided under said plate and between said blades in said second set of blades and said second opening being provided above said superior side of said plate.

6. A spreading device as in claim 4 in which said shaft is mechanically driven in rotation.

7. A spreading device for pulverulent matter comprising in combination a source of compressed gas, a hopper for said pulverulent matter, a stirring device in said hopper, a set of aligned and spaced nozzles, each nozzle in said set comprising a convergent portion, a divergent portion and a circular slot in said convergent portion, said slot having in an axial section through said nozzle an extended lip continuously receding from the axis of emergence of said compressed gas through said circular slot, a first system of pipes and couplings for delivering said compressed gas to each said circular slot, an assembly comprising a convergent portion, a throat and a divergent portion, said hopper being connected with and delivering said matter to said assembly; a second system of pipes and couplings connecting said assembly to said convergent portion of one of said nozzles disposed at one extremity of said set.

8. A spreading device for pulverulent matter comprising in combination a source of compressed gas, a hopper for said pulverulent matter, a stirring device in said hopper, a set of aligned and spaced nozzles, each nozzle in said set comprising a convergent portion, a divergent portion and a circular slot in said convergent portion, said slot having in an axial section through said nozzle an extended lip continuously receding from the axis of emergence of said compressed gas through said circular slot, a first system of pipes and couplings for delivering said compressed gas to each said circular slot, an assembly comprising a convergent portion, a throat: and a divergent portion, said hopper being connected with said assembly and delivering said matter to said assembly in the vicinity of said throat, a second system of pipes and couplings connecting said assembly to said convergent portion of one of said nozzles disposed at one extremity of said set.

9. A spreading device for pulverulent matter comprising in combination a source of compressed gas, a hopper for said pulverulent matter, a stirring device in said hopper, a set of aligned and spaced nozzles, each nozzle in said set comprising a convergent portion, a divergent portion and a circular slot in said convergent portion, said slot having in an axial section through said nozzle an extended lip continuously receding from the aXis of emergence of said compressed gas through said circular slot, an annular assembly comprising a convergent portion, a throat and a divergent portion, openings in said convergent portion, said hopper delivering said pulverulent matter into said convergent portion through said openings, a second system of pipes and couplings connecting said assembly to said divergent portion of one of said nozzles disposed at one extremity thereof.

10. A spreading device as claimed in claim 9 in which a moving belt passes in said assembly in said convergent portion thereof and in which said hopper delivers said pulverulent matter on said belt.

References Cited in the file of this patent UNITED STATES PATENTS 179,977 Turettini July 18, 1876 1,835,283 Crickmer Dec. 8, 1931 1,903,522 Uhn', Jr. Apr. 11, 1933 1,972,705 Crosthwait Sept. 4, 1934 FOREIGN PATENTS 766,498 France Apr. 16, 1934

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