DE1475160A1 - Pressurized gas atomizer for spraying liquids - Google Patents

Description

, Socie "te ¹ Anonyme de Machines Electrostatiques, 150, boite postale, 6frenol) le (Isere) / France

"Compressed gas atomizer for spraying liquids"

British priority dated September 27, 1963 from British Patent Application No. 38 172/63

The invention relates to a compressed gas atomizer for spraying liquids, in particular for dusting is determined by objects with finely divided liquid particles such as paint.

The pressurized gas atomizer proposed here is now according to the invention characterized by - within the atomizer body, Containing chamber with separate inlets, through which the liquid to be atomized on the one hand and the relevant Gas, on the other hand, into the chamber at a rate leading to at least partial atomization of the liquid are to be entered, and with at least one of the atomized liquid particles conveyed in the gas stream from the Chamber draining outlet · Preferably here is an organ

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provided that the liquid particles have an electrostatic ' Charge conveyed.

The inlets of this atomizer can face each other with the gas and liquid flows guided by them, or they can also enclose a Y-angle. The atomizer chamber can take various forms, for example cylindrical, the inlets provided separately for the gas and liquid flows in the side walls of the chamber and the outlet for the atomized liquid particles at one end. Instead, the chamber can also be annular be designed, its two side walls are each equipped with at least one inlet for the gas in question or the liquid to be atomized. In this latter embodiment, the multiple number of inlets for the liquid to be atomized open onto the circumferential inner wall and the gas inlets open onto the circumferential outer wall of the injection chamber. This arrangement is expediently made so that one gas inlet is opposite a liquid inlet »In addition, additional gas inlets can be provided that are not necessarily opposite liquid inlets, so that gas inlets may be present in a greater number than liquid inlets» Of course, it is also possible to to convey the gas to the inlets provided on the inner wall and the flow ¹ IgICeXt to the inlets in the outer wall

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According to a particularly preferred embodiment, show the outlet (s) leaving the chamber is one or more, each in the form of one directly connected to the chamber openings held in a narrow passage «, Instead however, the outlet (s) going out from the chamber can also have one or more each to a further, one outlet nozzle opening limiting chamber having leading passages

The electrostatic charge can be applied to the particles to be sprayed by applying a high DC voltage to the spray chamber or, instead, to the inlet (s) is applied through which the liquid to be sprayed is fed to the chamber, whereby this liquid is already is electrostatically charged prior to its entry into the chamber and prior to its atomization. Instead of that, however, "" Can apply this electrostatic charge to the particles already atomized after they have left the chamber. Furthermore In practice, air is usually used as the nebulizer gas, while other gases can of course also be used is.

Other features of the pressurized gas atomizer proposed here and advantages achieved by them will be apparent from the following description of the drawing, the compressed air atomizer of according to the invention in several exemplary selected embodiments schematically illustrated

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Pig. 1 to 7 show, in simplified cross-sectional images, various embodiments of the compressed air atomizer according to FIG the invention.

Figs. 8 to 13 each provide practical examples in longitudinal section ■ "• Exemplary embodiments of compressed air atomizers according to the invention Art.

The one in Pig. 1 reproduced compressed air atomizer a Serstäuberkörper 1 made of insulating material, in which a generally cylindrical chamber 2 is formed. Passages 5 and 4 are provided diametrically opposite one another opposite points open into chamber 2. Duron den Inlet 3 becomes a gas, for example air, at high speed passed and through the inlet 4 the relevant liquid to be atomized, such as paint, is conveyed. Gas and liquid thus enter the chamber 2 in opposing currents or jets and become so whirled together and mixed, creating the fluidity is atomized and then under the drive dee Gaeetromes the Chamber 2 leaves through the outlet opening 5. The atomized liquid particles are created by means of a high equilibrium tension Electrostatically charged to the chamber 2. Via a conductor 6, which is connected to the chamber wall opposite the outlet. This tension lttdt »unionst i the thin skin of fluid that forms on the chamber wall. '

and then-up the atomized particles.

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Fig. 2 shows another embodiment in which the outgoing from the chamber 2 outlet 5 leads to a further chamber 7 \ which in turn merges into an outlet opening 8, which is' connected to the outlet 5 in flight. This further chamber 7 enables a suitable mixture of gas and liquid and leads to an even stronger atomization of the latter. The embodiment shown in FIG. 3 differs from the embodiment according to FIG. 2 only in that the outlet opening θ in the rare wall of the chamber 1 is arranged at a right angle to the outlet 5, instead of being axially aligned with it, as in FIG Embodiment of Fig. 2 is the case.

In the embodiment shown in FIG. A , the outlet from the chamber 2 has a passage 5a which meets with a transverse passage 8a forming the outlet opening. the vibration cavities form, which further refine the atomization of the sprayed particles "

In the case of the in VIg. Further embodiment shown is 5 iu of the atomized liquid of the chamber 2, feeding inlet 4 at right angles to the inlet 3, is introduced via which the Oaa concerned in the chamber 2, and in axial alignment with the AftalasBQffnung 5. Aueβerdem the high extends

Pleiter C ₁ * Χ% de «the elektroatatisohe charge the Flüa-

'if -. ίΐ '' ■

L _r jjfitkeltattlloh * is imposed through the liquid inlet 4

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Pig, 6 brings an embodiment in which the outlet from the chamber 2 comprises three passages 5a, 5b and 5c, which are inclined at an angle to each other. The high-voltage conductor 6 extends through the liquid inlet 4 ·· Bei Of course, in all of these exemplary embodiments described above, several inlets leading to the chamber 2 can also be used 3 and 4 must be provided for both the gas in question and the liquid to be atomized

In Fig. 7, an embodiment is shown, which has a nebulizer chamber 2a in einform. The one to be atomized Inlet 4 carrying liquid is divided into two branches 4a, which are attached to one another on the inner wall of hanging chamber 2a open diametrically opposite points. The inlets 3 introducing the gas are on the outer wall of the annular chamber 2a each arranged opposite the liquid inlets 4. If desired, more than two radially arranged liquid inlets can be used 4a can be provided with a corresponding number of (yes inlets 3) opposite them. Also additional gas inlets can be provided so that the number of gas inlets is greater than the number of liquid inlets is. The conductor 6 for the electrostatic charging of the liquid to be atomized is on the wall of the liquid inlet 4 connected upstream of chamber 2a. A plurality of outlets 5 lead away from the ing chamber 2a and are arranged at regular intervals on a circular line and connected to the upper wall of the Bingkanimer 2a

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Pig. Figure 8 shows a practical embodiment of a nebulizer according to the invention with one at its upper end provided atomizer body 10, which is provided with a retaining cap 11 is secured via a connecting thread 12. The atomizer body 10 is hollow and contains a shaft 13 an enlarged head piece 13a, the circumference of which is seated on a shoulder 14 at the upper end of the atomizer body.10. That extended head piece 13a is provided with a ring kaumer 15, the four inlets 16 in its wall for equal distances the liquid to be atomized and four inlets 17 for the possesses the nebulizer gas in question. Each liquid inlet 16 is arranged opposite a gas inlet 17. The liquid inlets 16 are connected to a central bore 18, the extends axially along the shaft 13 and through which the liquid to be atomized is introduced. The gas inlets 17 are connected to axially aligned bores 19, which in turn are connected to the space 20 between the inner wall of the atomizer body pers 10 and the outer surface of the shaft 13 la are connected The gas is introduced into this space 20 via the connection 21 and then via the bores 19 and inlets 17 of the annular chamber 15 supplied. On top of the enlarged head piece 13a rests a disk 22, six of which are evenly spaced from one another Passages 23 1st, which the ring-

A seal 24 can be provided between the disk 22 and the outer part of the enlarged head piece 13a of the shaft 13. This of β ere Tell dee _r header 13a is reduced in its height, to the formation

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and to facilitate cleaning of the inlets 17. Above the disc there is a nozzle 25 which is designed with a nozzle outlet opening 26 in the form of a slot and which contains a further chamber 27 which is in communication with the outlets 23 of the disc 22. The various parts are held together by means of the retaining cap 11. The shaft 13, the disk 22 and the nozzle 25 can be made of an insulating material or ceramic. The atomizer body 10 and the retaining cap 11 can also be produced from an insulating material. The middle bore 18 is made electrically conductive by being lined with a metal tube 28 to which the high DC voltage is applied for electrostatic charging of the coating material.When this atomizer is in operation, the atomizing gas and the liquid to be atomized are fed into the chamber through inlets 17 and 16, respectively 15 introduced and atomized and electrostatically charged in it, whereupon the then atomized liquid particles in the gas stream carrying them flow through the outlets 23 into the further chamber 27, in which further atomization takes place, whereupon the atomized liquid then passes the nozzle outlet slot 26 in divergent or slit-shaped form Spray jets left.

Are at in Fig, 9 shown Ausführungeform to those of thirty. 8 provide the appropriate file with the same accessory . In this embodiment, too, four atomizer heads have a double atomizer body 10, a retaining cap 11 and

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a middle shaft 13 with an enlarged head piece 13a, in which a hanging chamber 15 is formed and the liquid to be atomized and the gas in question are supplied to the chamber 15 Inlets 16 and 17 are equipped as before. At this ■ ^ embodiment is, however, instead of a disk 22 on top of the enlarged head piece 13a of the shaft 13 a nozzle 30 arranged and with a plurality of outlet openings in the form of narrower Slits 31 are provided which are inclined outwardly with respect to the axis of the shaft and through which the atomized liquid is passed directly from the annular chamber 15. For example, six such outlet openings 31 can be used in the same way Be provided distance from each other. Each outlet opening 31 can have a Durohmesser of about 0.55min and opposite the The longitudinal axis of the atomizer head can be inclined at an angle of approximately 19. In the modified embodiment shown in FIG the nozzle 30 is equipped with outlet openings arranged in two rings, the inner ring 31a having three or has more equally spaced holes inclined by 10 ° with respect to the axis of the atomizer head, while the outer ring 31b at least three also at the same distance arranged to one another, to the axis of the atomizer head by 35 ° has inclined holes. The holes can now have a diameter of about 0.45.

In the case of the in fig. 11 brought embodiment, the parts 8 and 9 are provided with the same reference numerals as in Fig. 8 and 9, insofar as they correspond to these, is on top of the expanded Head piece 13a of the Sohaftes 13 a curved nozzle 32 is arranged,

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containing a Ringkarumer 15a, chamber 15 is provided for along with the enlarged in the '■ ·' ■ head 13a of the shaft 13 ring 'a everywhere annular chamber greater axial dimension. A plurality of inclined outlet openings in the form of narrow passages 33 are arranged around the tip of the nozzle, which protrudes forward from the retaining cap 11 of the spray head . has about 0.55 mm and is inclined by 60 ° with respect to the longitudinal axis of the spray head.

»12 shows another embodiment of an atomizer head, basically the same structure as that of the.Pig. In this embodiment, however, the curved nozzle is furthermore equipped with a central passage 34, which has a larger diameter than the narrow passages 33 owns. Within the central bore 18 through which the liquid to be atomized flows in, there is a valve 15 with a Valve head 37 displaceably arranged. The end 36 of this valve 35 adjoining the nozzle 32 is pointed to a nozzle needle, which inserts into the central passage 34 and closes it. The valve needle 35 is made of a metal; to them the high DC voltage is applied to electrostatically charge the coating material

The valve needle is axially movable from the position shown, in which the passage 34 is closed by the valve end 36 up to positions 'in which the valve end 36'

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pulled out of the passage 34 and access to the passage 34 is at least partially exposed. The annular outlet 38 from the central bore 18 closes when the valve end 36 is pulled out of the passage 34. In the position shown in the drawing, in which the middle passage 34 closed by the end 36 of the valve 35 and the Outlet 38 is completely open, the liquid pressure in the chamber 18a, to which the bore 18 is widened upwards, is greater than the pressure in the ring quay 15, and the atomizer works in the same way as the embodiment of Fig. 11, to spray the liquid through the passages 33 · When the end of the valve needle 35 comes out of the central passage 34 in is retracted to a position in which both this central passage 34 and the annular outlet 38 are open, the supply of liquid through the outlet 38 is reduced and the air pressure in the bores 19 and inlets' 17 is reduced greater than the liquid pressure in the chamber 18a. Then the atomized liquid stops flowing out of the passages 33, and the atomized liquid flows out of the chamber 18a around the valve pin through the central passage 34 "and" only air is discharged from the outer passages 33. The atomized liquid is in the central passage 34 through dae the pointed end 36 of the valve needle is electrostatically charged

In the further embodiment shown in FIG. 13, the charging of the liquid particles is completed by a corona discharge from a ring electrode adjoining the passages 33. Dieee construction is about ähnlieh of education

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leadership form the pig. 12, with the exception that the middle bore 34 is omitted from the nozzle 32 and the valve 35 UDi the nozzle tip is shortened «In this embodiment there is the shaft 13 made of metal, and the nozzle 32 is surrounded by a metal sleeve 39 which has a sharp edge 40 which protrudes from the surface of the nozzle'32 and that with the shaft 13 is in contact. the latter in turn flies to the DC charging source, so that the liquid discharged from the passages 33 is charged by the edge 40 The amount of liquid, which is mixed with the atomizing air to get out of the The nozzle to be sprayed through the outlets 33 is determined by the pressure or diameter of the liquid inlets 16 and Air inlets 17 controlled, and the liquid can with the valve 35 must be completely cordoned off.

Of course, the particular number and arrangement of passages and exit openings in the above play back anything W passed various embodiments are merely exemplary in nature and can be varied widely · The number of outlet openings and the types of their arrangement is significant for the definition of the spray and the spray pattern ·

In all the embodiments of FIGS. 8 to 13, the

Diameter of the enlarged head piece 13a between 12 and 50 mm «The volumetric dimensioning of the gas compared to that to be sprayed In the embodiment, liquid is equal to. 8 to. \ ' 11 in the Bndstrahl about 60 ι 1, but can "form" in the execution 12 and 13 may be variable. The gas velocity "*

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through the mixing chamber is between about 60 and 300 m / sec and the liquid velocity is about 30 m / sec. The speed of the spray jet emanating from the nozzle is also between 60 and 300 m / sec and largely depends on the pressure drop in the mixing chamber and between the mixing chamber and outside air.The atomizer works as an internal mixer and allows about 90 fa atomization of the liquid in the or the mixing chambers «A thin liquid film is formed on the wall of these chambers and the outlet openings, which is detached and atomized by electrostatic forces at the outlet edges of the outlets from which the spray jet emanates.

The DC high voltage can be generated by means of an electrostatic generator, which is a. Provides an output voltage of around 100 kV. However, it is possible to achieve the atomization by the atomizer according to ^ he invention, even without the use of electrostatic forces, so that the application of a voltage to the atomizing {DC not necessarily necessary. The atomizer head proposed here is not only easy to manufacture and assemble, but also easy to disassemble for easy cleaning.

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Claims (1)

Patent claims: : 1 ./Druckgaszerstäuber for spraying liquids, ■ for example paints, characterized by a chamber (2) contained within the Zeratäuberkörpers (1) with separate inlets (3, 4) through which the 'liquid to be atomized on the one hand (4) and the gas in question, on the other hand, (3) are to be introduced into the chamber at a rate leading to an at least partial atomization of the liquid, and with at least one the atomized liquid particles conveyed in the gas stream out of the the , . .
Drain chamber / outlet (5) ο 2. Atomizer according to claim 1, characterized by a the Liquid parts create an electrostatic charge Organ (6) » 3. Atomizer according to claim 1 or 2, characterized in that the inlets (3, 4) with the gas and liquid flows guided by them are directed frontally towards one another (Fig. 1 to 4). 4. Atomizer according to claim 1 or 2, characterized in that the inlets (3, 4) with the gas and liquid flows guided by them include a V / angle (Fig. 5, 7) _e - 15 - " 9098 Q4 / 0088 BAD ORIGINAL 5. Atomizer according to one of claims 1 to 4, characterized in, that the chamber (2) is cylindrical and that the chamber (2) is provided separately for the gas and liquid flows Inlets (3, 4) in the side walls of the chamber and the outlet (5) for the atomized liquid particles are arranged at one end thereof (Figs. 1, 2). 6. Atomizer according to one of claims 1 to 4, characterized in that that the chamber (2a) is annular and its two side walls each with at least one Inlet (3 »4) are equipped for the gas in question or the liquid to be atomized (Fig. 7). 7. Atomizer according to claim 6, characterized in that the inlets (4) for the liquid to be atomized on the circulating Inner wall and the gas inlets (3) open on the circumferential outer wall of the annular chamber (2a) (Fig. 7). 8. Atomizer according to claim 6 or 7, characterized in that a gas inlet (3) each has a liquid inlet (4) opposite (Fig, 7). 9. Atomizer according to one of claims 6 to 8, characterized in that that additional gas inlets (3) are provided. 10 · Atomizer according to one of the preceding claims, characterized characterized in that the one or more from the chamber (2} 2a) BATHROOM ORIGINAL - 16 - 909804/0088 going outlets (5) one or more each in the form of a narrow passage directly connected to the chamber have retained openings. ο Atomizer according to one of Claims 1 to 9, characterized in that that the 'resp. the outlets from the chamber (2) one or more each to a further, a chamber (7) delimiting an outlet nozzle opening have passages (5) (Fig. 2), 12e atomizer according to one of the preceding claims, characterized characterized in that the outlet going out of the chamber (2) is a transverse one with one which forms the outlet opening passage (8a) has converging passage (5a), which two passages (5a, · 8a) into the atomization Sack parts (5b, 8b) which refine the sprayed particles and form vibration cavities end (Fig. 4) 13. Atomizer according to one of the preceding claims, characterized in that the chamber (2) to one of the to be sprayed Particles a high DC voltage imparting electrostatic charge can be applied (Fig. 1 to 4), 14. Atomizer according to one of claims 1 to 12, characterized in that the or the liquid to be sprayed inlets (4) leading to the chamber (2 $ 2a) to one of the. ! . BAD ORlGSNAL ■ 909804/0088 liquid to be sprayed before it enters the chamber and thus an electrostatic one before it is atomized Charge-conveying high DC voltage can be applied (Pig. 5 Ms 7). 15. Atomizer according to one of claims 1 to 12, characterized in that that an electrical system is provided that the atomized liquid particles after leaving the Chamber can impose an electrostatic charge. 16. Atomizer according to one of claims 7 to 9> characterized in that that within the atomizer body (10) a shaft (13) with an enlarged head piece (13a) is arranged is that with the gas inlets (17) in its outer wall and the inlets receiving the liquid to be sprayed fed through a bore (18) provided in the shaft (16) is equipped in its inner wall owning hanging chamber (15) (Fig. 8 to 13). 17 · Atomizer according to claim 16, characterized in that A disk (22) is seated on the enlarged shaft head piece (13a), the passages connected to the annular chamber (15) (23) which, on their side facing away from the annular chamber, open to another into an outlet nozzle opening (26) Guide chamber (27) (Fig. Θ). - 18 BATH ORIGINAL 9Ü980W009fl 18. Atomizer η. eh Ansijruch 16, dc characterized in that a nozzle (30) is placed on the enlarged shaft head piece (13a)
sits on, which is provided with several passages (31) connected to the ring kaiiimer (15) (Fig. 9 »10)» 19 · Atomizer according to claim 18, characterized in that the nozzle (32) has an annular cavity (15a) which is in communication with the cylinder (15) and extends its axial length, from which the outlets (33 ) away (Fig. 11 to 13) ο 20o atomizer according to claim 19 »characterized in that da3a in the bore (18) of the shaft (13) one for controlling the flow of the liquid to be sprayed through it axially adjustable nozzle needle (35) is arranged (Fig. 12, 13). 21. Atomizer according to claim 20, characterized in that theo ι the nozzle (32) is surrounded by a ring made of electrically conductive material for applying the low-voltage voltage 22, atomizer according to claim 20, characterized in that a central bore (3 *) is provided in the nozzle (32), in which the nozzle needle (35) with its end controls the liquid stream flowing through this bore (36) protrudes
(Fig. 12). - 19 - BAD ORIGINAL 30980-4 / 0088 U7516Ö 23 · atomizer, according to one of claims 20 to 22, characterized ^ marked that there is a DC voltage at the nozzle needle (35) 24 ". Atomizer according to one of Claims 16 to 19, characterized characterized in that the wall (28) of the shaft bore (18) ordered for the installation of a direct high voltage made of electrically conductive material (Fig. 8, 9, 11). BAD ORKMNAL 909804/0088