DE916638C - Method and device for atomizing liquid or dusting powdery substances in finely divided form - Google Patents

Description

P. 175)

ISSUED AUGUST 12, 1954

S 25931 r / 85 g

Henri Coanda, Paris

has been named as the inventor

is used

The invention relates to a method and a device for atomizing liquid or Dusting powdery substances in finely divided form.

In the method according to the invention, the physical process referred to as the Coanda effect is used used for atomization and / or atomization, in which to generate a high negative pressure one side on the outside of the gap opening of a gas stream under low pressure protruding lip is arranged.

The device according to the invention consists of one with compressed air or another under pressure standing gas supplied system of suction and pressure nozzles, on which gaps are provided, which enable the Coanda effect to occur.

These nozzles are designed in the manner of Venturi tubes, and the compressed air or the compressed Gas passes through a gap, the mouth lip of which is at a steadily increasing distance with respect to the The exit direction of the gap is extended into a flow channel, the Coanda effect occurring.

As is known, a fluid that emerges through a gap formed in this way nestles tightly against the extended lip, increasing its exit speed and creating a vacuum, through which air is sucked in. This Coanda effect is used by the compressed air or the compressed gas entrains an additional amount of air and / or the material to be atomized, regardless of whether this air or the Zer

dust is mixed with the atomizing air or the atomizing gas or not.

The device according to the invention essentially comprises a pressurized gas source, consisting either of a pressurized gas cylinder or another compression device, also a system of tubes, which can be either fixed or telescopically structured around one or more axes pivotable or flexible, and one or more of the type a venturi tube shaped nozzles, which cooperate with circular, narrow, at least approximately mounted in the vicinity of the constricted nozzle part columns whose a mouth lip of the outlet axis of the gap is extended in such a way in a continuously increasing distance with respect to that it to the exit axis of a preferably between 25 and 50 ⁰ lying angle forms.

In a first embodiment of the Erfindungsao object is described, the gap within a nozzle through which emerges the compressed air or the compressed gas, wherein the elongated orifice lip of this gap has gap with respect to the exit direction of a lying between 25 and 50 ⁰ angle. In the interior of this nozzle sits an axially arranged tube through which the substance to be atomized or atomized, for example a liquid or a powder, is fed. This tube is preferably designed in the manner of a Venturi tube, and its mouth edge is set back with respect to the mouth edge of the pressurized gas channel. The compressed air or the compressed gas now pulls additional air with it when it exits the compressed gas duct, and the substance to be atomized or atomized is carried away by the total amount of air composed of the compressed air and the entrained secondary air, whereby it is due to the action such a large amount of pressurized air or gas is atomized into very fine particles. This is particularly the case when the material to be atomized is supplied in the form of a very thin layer, as in an exemplary embodiment to be described later.

In a second embodiment, several nozzles designed according to the Coanda effect are arranged, namely one or more primary nozzles of small dimensions and a second nozzle into which the material to be atomized is blown in from the first nozzle. Both nozzles are for example operated simultaneously with compressed air, which passes through a circular gap according to the Coanda effect exits, so that the compressed air emerging from each gap also air or that from the upstream Nozzle sweeps away any material that has already been atomized. The liquid or liquid to be atomized the powder to be atomized is taken from a container through which the one sucked in by the first nozzle Air sweeps through. This container may contain means for stirring the too atomizing good present.

Means can also be provided on the device according to the invention, which breakdown the liquid to be atomized or the powder to be atomized in extraordinary facilitate fine particles so that these particles can more easily be kept in suspension. the however, means given in the further description for this purpose are not intended to be part of the invention whose main feature is based on applying the Coanda effect to a nozzle system, with the use of air or other gas masses under low pressure on the one hand, allow large masses of air or gas to be carried away and, on the other hand, intimate mixing these large masses with a powder to be atomized or a liquid to be atomized is possible. The invention is also directed to a combination of one type of venturi with a gap formed for the Coanda effect or a gap formed through which the Compressed air or the compressed gas passes through it and here secondary air or with the to atomizing liquid or air laden with the powder to be atomized.

The subject matter of the invention is intended below Hand of the drawing will be explained in more detail. It shows

Fig. Ι an enlarged view of a nozzle acting according to the Coanda effect,

Fig. 2 shows a device according to the invention using the nozzle of FIG. 1, partly in Section, partly in the side view,

3 shows a schematic side view of a device with a compressor and two nozzles,

FIG. 4 is an enlarged view of the nozzles according to FIG. 3, specifically in longitudinal section.

FIGS. 5 and 6 show a schematic representation of two preferred embodiments of the device for atomizing the liquid, too

7 and 8 are schematic representations of two preferred embodiments of a device for atomizing powder.

It is known that the atomization of liquids can be effected by by means of a stream of air, tears off particles from a liquid mass and moves them in any direction hurls away. In general, atomization takes place by means of a nozzle emerging from a nozzle Air or steam jet. The nozzle acts, for example, via a type of Venturi nozzle or directly in that it is provided above the outlet opening of the channel of the liquid to be atomized. In both cases, a negative pressure is created at the exit point of the liquid, through which the liquid is torn away and more or less finely divided in the process. The exit speed of the air or steam jet exiting under pressure is dependent on the pressure prevails in this jet shortly before it emerges from the nozzle. The liquid can then be used act via the mass of the jet, which depends on its surface and its speed, if you force the jet against the much slower flow of the emerging from the opening Allows liquid to impinge. Through this

On impact, the smaller amount of liquid is broken up and thrown away in the form of more or less homogeneous droplets in the direction of the steam jet.
The entrainment of the liquid can also be achieved via the contact surface of the entrainment jet and the liquid to be entrained, in the latter case the entire mass of a cylindrical jet is only slightly utilized. ίο If the cylindrical jet is a hollow jet, however, the mode of action is completely different because the ratio between mass and contact area with the liquid is smaller. If the thickness of the cylinder jacket of the jet is extremely small, the contact surface with a liquid surrounding it becomes very large, the liquid particles are carried away without impact, which means that these particles are very homogeneous and very fine and are very well distributed in the overall jet that emerges. The efficiency of this process is then extremely high. The above statements naturally also apply to the atomization of powder or similar substances.

According to FIG. 1, a stream coming from the compressed gas duct 2, for example compressed air, enters an annular gap 1, from where it flows out into the hollow cylinder 3. A gap edge 4 is extended to a lip 5 which forms a lying between 25 and 50 ⁰ angle to the opening direction of the gap 6. 1 According to the Coanda effect, the outflow speed accelerates around the sharp edge 7, and a high negative pressure is formed along the wall 8 of a cylinder 8 ', which is the extension of the lip 5. As a result of this negative pressure, air 9, which enters the convergent part 10, is sucked in, as a result of which the mass of the entrainment air exiting through the compressed gas duct 2 and the gap increases without, however, significantly reducing the flow rate.

A suction pipe 11 for the liquid is built into the interior of the cylinder 8 '. To the touch area the liquid brought up in the tube 11 with the liquid flowing through the hollow cylinder 3 To enlarge air is the mouth 12 of the tube

11 internally divergent, so that the through the suction pipe 11 brought up liquid along the walls of the divergent Part unfolded. The rapidly moving air layer, which is opposite to the hollow cylinder 3 Surrounding somewhat recessed, divergent mouth 12 of the tube n, which tears along its length the wall of the divergent mouth

12 moving particles along with it and hurls them to form a mixture consisting of liquid particles 13 and air 14 Outside.

At the outlet of the divergent mouth 12 there is a negative pressure, whereby the Liquid necessarily at a speed in the same direction as that which arrives with the air 9 being carried away, and there is then only an acceleration of one in Fluid movement instead of a sharp transition from speed Zero to the speed of the entrainment jet.

Since the entrained layer becomes extremely thin, the surface pressure of the liquid allows it not to maintain a continuously uniform surface, and the thin layer of liquid breaks up into homogeneous droplets and is thus carried away into the final jet. When the air supply is turned off, for example by means of a diversion installed in front of the air inlet, disappears the negative pressure prevailing at the outlet of the divergent part 12 immediately, and the liquid also stops moving immediately.

In the atomizer shown in an overall view in FIG. 2, an opening 15 is provided which serves to divert the air. If this opening is open, the device stands still; becomes the opening but closed, for example by holding up the thumb, the air sets its own Away in the device in the manner described above.

An atomizer of the type described does not require high pressures, because the utilization of the Coanda effect allows the use of relatively low pressures.

If a liquid of sufficiently high viscosity is used, the can on the container 16, the contains the liquid to be atomized, pressure exerted via line 17 by means of a pressure regulator (not shown in the figure) are regulated.

The device shown in Fig. 1 and 2 is not limited to liquids, but can can also be used for powdery substances.

In Fig. 3 and 4, a second embodiment of a device is shown, which makes it possible by applying the physical process known as the Coanda effect to one with compressed air or compressed gas fed system of suction and pressure nozzles either an atomization or a Dusting or both at the same time. This system of nozzles is preferred swiveling and possibly adjustable, so that it is brought to a certain height can be.

Because by means of a system of nozzles that utilize the Coanda effect by suction, large Masses of air can be carried away, these air masses can be particles of liquid and suspend solid substances and carry them up to certain distances.

The entire system of the second embodiment according to the invention can either be carried or be driven.

In Fig. 3, an air compressor 21 blows over the telescopically arranged tubes 22 compressed air after a rotatably arranged about the axis of the tubes 22 Tube 23 to which a tube 25 is attached by means of a toggle lever or joint 24. the Air is supplied to the nozzles 28 and 27, which are designed in the manner of Venturi tubes, by means of the pipeline 25

and a diversion 26, in which a control slide 2Ö ^{6 is} installed, fed. The compressed air penetrates into the nozzles 27 and 28 through gaps, which are designed as mentioned above in order to utilize the Coanda effect and are denoted by 47 and 46 in FIG. The compressed air passing through the gap 46 entrains additional air 29 in the nozzle 28 in addition to the air 30 coming from the nozzle 27. The mixture formed in the nozzle 28 exits at 31. The negative pressure generated in the convergent part of the nozzle 27 in turn entrains an air mass 32 charged with the substance particles to be spread through the hose 33. The hose 33 is in turn connected to a telescopic arrangement 34 which emerges from the container 35 in which the substance to be spread is located. At the bottom of this container 35 holes 3 and ^{6 are} made through which the air enters. This air sweeps past an agitator 36, which is supposed to maintain a possibly regular supply of the substance to be spread, which is located in the container 35.

By means of the ropes 37, which lie on the pulleys 41 and 42, it is possible to move the tube 23 around to move its vertical axis. About the vertical adjustment of the telescopically arranged tubes 22 to be able to follow, small chains 40 are attached to the ends of the ropes 37, the links of which are attached to the Housing of the fixed compressor 21 can be hooked. To move the tube 25 in order to enable the longitudinal axis of the joint 24, one is actuated by cables 43 and chains 39 double-armed lever 38 is provided.

From Fig. 4, in which the arrangement of the nozzles 27 and 28 is shown schematically in longitudinal section it can be seen how the air coming from the pipe 25 and the bypass 26 clears the gaps 46 and 47 feeds. The extended mouth lip of the gap 46 is provided with small surfaces 45 and at the same time forms the inner wall of the convergent part of the venturi tube formed nozzle 28. The one coming through the line 25 and exiting through the gap 46 As a result of the Coanda effect, air forms along the wall formed by these small areas 45 a negative pressure which sucks in the air 29, 30 coming from the outside.

In the nozzle 27, the entrainment process takes place in the same way, but instead of pure air, a Air mass 32 in which the particles of the substance to be spread are suspended, entrained. This air mass 32 is withdrawn from the container 35 via the hose line 33.

In Fig. 5 and 6 is the aforementioned device for atomizing a substance, which then is carried away by the suction air. This device preferably consists of a device through which the sucked-in air flows Container 53 rotating disk 49. The disk 49 rotates about its axis 50; these In the embodiment shown in FIG. 5, rotation is generated by that in line 59 Negative pressure, through which the air coming from 54 is sucked in, causes. This air will through the fixed blades 52 to the movable ones attached to the underside of the disk 49 Paddles S1 passed so that the disk 49 rotates. That coming from the container 55 via the line 56 and accumulating in the center of the disk 49 Liquid to be spread is thrown off in the direction of the arrows 57 as a result of the centrifugal force. The one between the blades 52 and 51 Air passing through meets the effect of centrifugal force when it enters the container 53 thrown away liquid, with which it mixes and which it after the zone 58 of the Container 53 and from there to line 59 is carried away. Fig. 6 shows a modified atomizing device. Only the drive device is different from that of the device according to FIG. 5, namely is the movement to be transmitted to the disk 49 by means of a two conical pinion gear Friction gear 60 causes. The transmission 60 is via a belt pulley seated on the shaft 61 63 driven by a motor (not shown in the drawing). A tight housing 62 protects the transmission 60.

7 and 8 are two preferred embodiments the devices for entrainment of powdery or granular substances shown.

According to FIG. 7, a constriction 66 is arranged on a nozzle formed in the manner of a Venturi tube and consisting of a boundary surface 64 and a double cone 65. At the edge of this constriction 66 there are columns 66 ^& . The air coming from 69 and rising after the pipe 76 reaches its highest speed in the constriction 66 and consequently its best suction capacity.

A container 67 contains pulverulent or granular material to be atomized 68, which is continuously brought to the gaps 66 ⁶ by the agitator 72 . The mixture consisting of air and the entrained substance is fed via line 76 to nozzles 27 and 28 (FIG. 4). The double cone 65, which is arranged axially to the delimiting surface 64, is fastened on the rod 70 carried by the bracket 71.

The modified embodiment of the device according to FIG. 7 shown in FIG. 8 consists of a convergent boundary surface 64, in front of which a conveyor belt 73 provided with holes 75 moves. The latter is driven by means of the rollers 74; An agitator 72 is mounted on the axis of one of the rollers 74 and vigorously agitates the atomized material 68 located in the container 67 for the purpose of regulating the supply of the same. The air 69 sweeps through the holes 75 made on the belt 73 and carries the fabric spread out on the belt 73 with it. If a part of the material has not been carried away, it is held back by the air entering ^{at the convergent part 7s 6;} the mixture consisting of air and the substance to be spread reaches the nozzles 27 and 28 via line 76 (FIG. 4).

Claims (14)

Patent claims: ι. Process for atomizing liquid or powdery substances in finely divided form by means of a pressurized gas stream, characterized in that under utilization the known device for beam deflection, which is suitable for generating a high negative pressure and in the Outside of the gap opening of the gas stream under low pressure on one side a lip protruding in the desired direction of deflection is arranged, in addition air sucked into the pressurized gas channel and the material to be atomized by this reinforced guest electricity is carried away. 2. Device for performing the method according to claim i, characterized in that the compressed gas channel (2) has a nozzle with an annular gap (1) and an inlet opening for the outside air and that a gap wall (4) to a projecting, to the mouth direction ( 6) of the pressure gas stream sloping lip (5) is extended, which forms a lying between 25 and 50 ⁰ angle to the opening direction (6). 3. Apparatus according to claim 2, characterized in that the compressed gas channel (2) in a hollow cylinder (3) opens, the outer wall of which is formed by the protruding lip (5) and the one for the supply of the atomizing material axially arranged supply pipe (11) surrounds ring-shaped, the mouth (12) is widened in a funnel shape and whose mouth edge is slightly set back from the mouth edge of the hollow cylinder (3) (Fig. Ι and 2). 4. Apparatus according to claim 2, characterized in that the compressed gas flow and the The atomizing material sucked in by it emerges through a nozzle (27, 28) which, in the manner of a Venturi tube is formed (Fig. 3 and 4). 5. Device according to one of claims 2 to 4, characterized in that the inlet opening for the additional outside air before annular gap (1) is narrowed in a funnel shape (Fig. ι and 2). 6. Apparatus according to claim 4 or 5, characterized in that it consists of several assembled, consists of individual devices similar to the overall device (Fig. 3 and 4). 7. Device according to one of claims 2 to 6, characterized by a compressor (21) for generating compressed gas, for example via pipelines to a venturi-shaped set trained nozzles is connected (Fig. 3). 8. Apparatus according to claim 7, characterized in that in the funnel-shaped narrowed part of the nozzle annular gaps (66 ^ft ) are attached, through which the compressed gas from the compressor (21) flows via the pipelines, a mouth lip of this column in continuously increasing Distance with respect to the exit axis of the compressed gas stream is lengthened (Fig. 7). 9. Device according to one or more of claims 2 or 4 to 7, characterized by a small primary nozzle (27) through which the compressed gas and the material to be atomized Existing mixture exits, and through a larger secondary nozzle (28) into which the from The mixture sucked in through the primary nozzle is displaced, with the secondary nozzle also having air sucks in, increases the speed of the mixture and this with accelerated speed flings out of the device (Fig. 3 and 4). 10. Apparatus according to claim 7 or 8, characterized in that the pipelines (22, 23, 25) vertically extendable, rotatable about the vertical axis and with respect to the horizontal Axis are pivotably arranged (Fig. 3) 11. The device according to claim 2 for atomization of liquids, characterized by a rotating disk (49) built into the pressurized gas flow, on the upper side of which the to be atomized Liquid is preferably supplied centrally via one or more supply pipes (56) is so that the thrown from the disc (49) liquid through the pressurized gas flow gets carried away. 12. The device according to claim 11, characterized by a mechanical device driving the rotary disk (49), e.g. B. a Friction gear (60), on the drive shaft of which a belt pulley (63) is attached (Fig. 6). 13. The device according to claim 11, characterized by movable blades arranged on the underside of the rotating disk (49) (51) and this upstream, on the atomizer container (53) fixed fixed blades (52) in the manner of turbine blades, so that the disk (49) rotates through the flow of pressurized gas is offset (Fig. 5). > ° 5 14. Device according to one of claims 7 to 9, in particular for atomizing a dry, powdery or granular substance, characterized by a storage container (67) which is connected to the pressurized gas channel (76) and contains the atomized material (68), the discharge openings of which are in the narrowest Gap (66 *) of the venturi-shaped nozzle of the compressed gas channel open out, and an agitator (72) built into the storage container (67 ) for conveying the preferably powdery material to be atomized (68) (FIG. 7). Referenced publications: German patent specification No. 657 397. For this purpose 2 sheets of drawings © 9536 8.54