US3004717A - Apparatus for producing an aerosol - Google Patents

Description

Oct. 17, 1961 Filed April 25, 1958 K. FLURY APPARATUS FOR PRODUCING AN AEROSOL In. Me n' Y" 3 Sheets-Sheet 1 A TfQfP/VE v5 K. FLURY 3 Sheets-Shea? 2 Oct. 17, 1961 APPARATUS FOR PRODUCING AN AEROSOL Filed April 25, 1958 Oct. 17, 1961 v K. FLURY 3,004,717

APPARATUS FOR PRODUCING AN AEROSOL Filed April 25, 1958 3 Sheets-Sheet I5 Irv/emi 3,004,717 Patented Oct. 17, 1961 3,004,717 APPARATUS FOR PRODUCING AN AERQSOL Karl Flury, Adliswil, Zurich, Switzerland, assignor to Defeusor AG, Zurich, Switzerland Filed Apr. 25, 1958, Ser. No. 731,014 Claims priority, application Switzerland Apr. 27, 1957 3 Claims. (Cl. 239-224) This invention relates to an apparatus for producing an aerosol. The apparatus comprises a driving motor, an impeller driven by the same for producing an air current and, also driven by the same motor, a centrifugal disk adapted to throw out to a film a liquid supplied thereto, being broken up in mist droplets by the air current striking axially over the periphery of the centrifugal disk.

In contradistinction to known appliances of the type, the apparatus according to the invention is principally characterized in that the diameter of the centrifugal disk is smaller than that of the impeller with centrifugal action.

Further features of the invention will appear from the following description and claims, taken in conjunction with the accompanying drawing which shows several forms of embodiment incorporating the invention.

In said annexed drawing:

FIG. 1 shows partly in elevation and partly in longitudinal section a first form of embodiment of the apparaatus according the invention;

FIG. 2 shows in similar representation a fragmentary view of a part of a second form;

FIG. 3 shows partly in elevation and partly in axial longitudinal section the fore part of an apparatus for producing an aerosol according to a third form;

FIG. 4 is a fragmentary view of the apparatus, seen from the righthand side in FIG. 3;

FIGS. 5, 6 and 7 are sectional views showing modified forms of jets;

FIG. 8 shows partly in side view and partly in axial longitudinal section the fore part of a last form.

The essential constructional features and advantages of the apparatus shown in FIG. 1 are as follows: an electric motor a located within an internal casing part b having vanes c which extend substantially parallel to the rotary axis of the motor. With the aid of said vanes c the internal casing part b is removably inserted into an external or forward casing part d. The casing parts b and d have, provided therebetween, an air guiding channel 2 of circular cross-section gradually decreasing towards and opening at top in FIG. 1. a

A rear casing part 1 is detachably secured to the forward casing part a by means of screws g. The said two casing parts have clamped therebetween the peripheral margin of a circular air baffle plate h. The rear end of the motorshaft i carries an impeller k of the centrifugal action-type which is arranged between said baflle plate h and the internal casing part b. The rear casing part 1 has openings for the intake of air which is then forced by the impeller into the channel e and blown out through a circular gap at the forward end of the casing. As apparent from FIG. 1, the channels imparts to the air current a motion component converging towards the axis of the motor.

The forward end of the motor shaft i carries two centrifugal disks l which, when at rest, elastically engage each other peripherally. Said disks are disposed immediately in front of the respective end of the casing, i.e. outside it, the diameter of the disks substantially coinciding with that of the casing part b. The air current issuing from the channel e flows in axial direction of the disks l past the peripheral edge thereof. The diameter of the disks is much smaller than that of the impeller k.

The motor shaft i is hollow and serves to supply the liquid into the space between the two disks 1. The forward end of the hollow shaft i is sealed by a screw m, whereas the rear end thereof communicates with a liquid tank n. Within the tank It there is a flexible hose 0 which at one end is pushed over a nipple p fixed to the casing part 1, the other end thereof dips into the tank down to its lowest level. From the nipple p, the liquid arrives at a regulating valve r, the outlet orifice of which is governed by a threaded spindle s. From the valve r, the liquid flows through a bellows t into the hollow space of the shaft i. The rear end of the shaft 1'. carries a hub it having a slip ring v. A flange ring y joined to the bellows t has a slip ring at which bears against the slip ring v under the action of a spring 2 so as to ensure at all times a perfect seal between the stationary bellows t and the rotating shaft i.

For governing the amount of liquid to be atomized, the valve spindle s can be turned by means of a knob a and hence also be adjusted axially. Another knob b coaxial to the knob a has an abutment c for the knob a. A restraining spring d has for its duty to render the knob b adjustable only by overcoming appreciable frictional forces, in any case much more diflicultly than the knob a. The knob a allows setting of the amount of liquid from zero up to a maximum value which is fixed by the momentary setting of the knob b and in dependence of the properties of the liquid to be atomized. The fluid tank It is secured against the lower part of the housing 1 by means of diametrically opposite tension levers 2' through the intermediary of an elastic ring f and after release of the levers e may be removed. In order to provide for easy insertion of the fluid the tank n is provided with a filling opening which is closed by a cap g. This cap g is made of an elastic synthetic material and seats in a sleeve having a sieve bottom h secured in the filling opening in the tank It and which is secured in place due to its elasticity. The sieve bottom h serves to filter the fluid inserted in the tank n. Arranged with the closing screw m in front of the disks 1 is a hood in adapted to serve also as flow cone for the aerosol being produced.

Swivably and detachably mounted on the casing part d are the two limbs of a stirrup-shaped supporting member n, each of which being offset twice in opposite directions. One elbow 0' of each limb can rest against the rear casing part 7, as shown in FIG. 1.

With shaft i rotating and valve 1- open, by the action of the centrifugal disks, liquid will be drawn from the tank It into the hollow space of the shaft i and thrown out between the disks 1, the liquid being spread to a thin film. Simultaneously the impeller k produces by its centrifugal action an air current which impinges on the liquid film substantially at right angles, breaking the same up into tiny mist droplets forming an aerosol in the air current. For the atomizing performance of the apparatus it is of decisive importance that the diameter of the disks 1 be smaller than that of the impeller k. Thus it will be achieved that, when leaving the casing, the blowing force of the air current in axial direction of the shaft i is greater than the centrifugal force of the liquid droplets leaving the disks 1. Hence the droplets will be safely engaged by the air current and carried along.

If the sealing and slip rings v and x must be replaced, all that has to be done is to loosen the screws g and to remove the rear casing part 1 from the casing part d, whereupon the baflle plate It may be readily taken out in order to expose the impeller k for possible cleaning or dusting. If the motor a is to be removed, the internal casing part I) together with motor, impeller and disks can be withdrawn reaiwards from the casing part d. The vanes c thereby serve for guiding the part b in the part d. In service condition of the apparatus, the

vanes c will, however, serve to stabilize the current of air, to prevent the same turning round the rotary axle of the centrifugal disks, which would impair the production of mist.

The described manner of attaching the tank It has the advantage that a possible shrinkage or swell of the sealing ring f does not adversely affect the tightness or dismountability. With the tank n removed from the casing part f, the liquid to be atomized may be, if necessary, suckedup by means of a hose or directly out of another container, say, a canister. If the supporting member 11' is arranged in a position inversely to that shown so that its two limbs interchange their places, the apparatus may be mounted on the marginal portion of a canister provided with handles in such a way that said member is pushed through one of said handles.

The form shown in FIG. 2 is distinguished from that described by the fact that only a single centrifugal disk p is provided instead of two disks 1. This single disk is bell-shaped, situated symmetrically to the rotary axis of the shaft i and open towards the respective end of the casing, i.e. against the outlet of the air flow. The extreme peripheral edge of the disk p acts exactly identically as the peripheral edge of each of the disks 1. The atomizing efficiency of the form according to FIG. 2 is practically the same as in the first form.

When atomizing aqueous liquids with the forms described hereinbefore it may happen that a portion of the liquid droplets on being thrown off the disks cannot traverse the air flow owing to the centrifugal action without being entirely engaged by the air current and carried away.

To obviate this disadvantage, according to the invention, a ring of stationary lamellae is arranged radially outside the peripheral edge of the centrifugal disk and in the path of the air flow.

The liquid particles, which otherwise would escape outwards, will be retained by these lamellae, to be then, by the air flow, blown off the lamellae in the desired direction.

Examples of embodiment of this type are illustrated in FIGS. 3-7, in which like reference characters indicate like parts as in FIG. 1.

According to FIG. 3, the forward part of the hollow motor shaft i again has mounted thereon two centrifugal disks 1 resiliently engaging each other at their peripheral margins. Provided between said disks is a hollow space communicating through radial apertures 2 with the in her space of the hollow shaft i. A spacer 3 provided with radial passages is interposed between the disks l. One disk I lies against a hub 4 on the shaft i, and the other disk I has a cap '5 pressing against it by means of a screw m which threadedly engages the end of the shaft' i sealing its hollow space towards outside.

Mounted on a suitably reduced portion of the internal casing part b is an annular member 6 fitted with a ring of lamellae 7 which are firmly arranged radially and equidistantly outside the peripheral edge of the centrifugal disks I. Said lamellae project into the outlet gap of the air guiding channel 2 and extend to the outer casing part 0?. From FIG. 4 it can be seen that the lamellae 7 are radially inclined with respect to the shaft i so as to stand substantially at right angles to the moving direction in which the liquid particles impinging on the respective lamella would be thrown off the edge of the disks I if no air would flow through the channel e. The said moving direction of the liquid particles is the direction of the velocity vector Ve composed of a velocity component Vt derived from the rotation of the disks 1, which runs at a tangent to the circumference of the disks, and a velocity component Vr, also derived from the centrifugal force, which runs radially to said disks. Moreover, the lamellae 7 are so disposed in relation to each other that, seen in the direction of the velocity vector Ve from any peripheral point of the 4. disks 1, the lamellae 7 neighboring each other cannot be freely looked through therebetween, in other words, no liquid droplets from the periphery of the disks I can be thrown out between the lamellae 7.

The other parts of the apparatus, not illustrated in FIGS. 3 and 4, are designed similarly as in the form according to FIG. 1.

The action of the described apparatus is as follows: With motor a switched-on, the centrifugal disks 1 will start to rotate in the sense of the arrow R in FIG. 4. Incidentally by the centrifugal action of the disks, liquid from a tank (not shown in FIG. 3) will be drawn into the hollow space of the shaft i and thrown out between the disks 1, the liquid, upon passage through the narrow gap between the two disk margins, being spread to a thin film. Simultaneously the impeller (also not shown in FIG. 3) produces an air current through the channel e. The air current leaving the outlet gap of said channel blows substantially at right angles to the said liquid film, breaking it up in tiny mist droplets which are carried offin the air flow and form an aerosol, as shown at A in FIG. 3. Those droplets, properly engaged by the air flow, will impinge on the lamellae 7 and thus be prevented from flying further out radially. At the lamellae 7 condensate will form which, as the lamellae 7 are arranged in the air flow, is blown off and atomized also in fine mist droplets as shown at B in FIG. 3. At some distance from the described apparatus, the mist rays A and B coalesce.

Through the lamellae 7 the intended formation of mist is improved.

The form shown in FIG. 5 is distinguished from that described only in that the end of the lamellae 7 oriented in the direction of the air flow has a sloping limit. As a result, each lamella has a thin wedge end 8, on which the condensed liquid will be chiefly blown oif to form the mist rays B.

In the form according to FIG. 6, the lamellae 7b are likewise given a thin wedge end 8 which, however, due to inverse sloping end limitation of the lamellae is now disposed more inside. Another difference of the form according to FIG. 6 is that the lamellae 7b are arranged on an annular member 6a supported by the outer casing part d. Further, the lamellae 7b do not extend to the inner casing part b, but only to an additional ring member 10 adapted to subdivide the outlet gap of the air channel e into an inner and an outer section. The lamellae 7b only extend into the outer section of the outlet In the forms of embodiment so far suggested with two centrifugal disks, these are provided with oppositely inclined conical peripheral sections and formed of comparatively thin material. Upon rotation of the centrifugal disks, the conical peripheral portions tend to deflect outwards and are thus; separated from each other due to the centrifugal action. At high speeds, this involves the drawback that the gap between the peripheral edges of the two disks becomes intolerably large, as in such case undesirably great liquid droplets would be formed.

To circumvent this disadvantage, according to the invention, one of the centrifugal disks is of rigid design and provided at its peripheral portion with .a conical inner surface, the other disk being elastically pliable and has a conical peripheral portion which is inclined in the same direction as the conical inner surface of the rigid disk, engaging the same circumferentially under centrifugal action. i

A corresponding form is shown in FIG. 8, 'in which similar reference characters represent similar parts as portion 13 inclined towards the outlet gap of the air channel e. A second centrifugal disk 14 is also mounted on the shaft i and clamped between the hub 11 and a cap 15. A screw m threadedly engaging the end of the shaft i serves both to seal the hollow space thereof to the front and to press the cap 15 against the disk 14 which is of rigid design and has likewise a conical peripheral portion 16 inclined towards the outlet gap of the air channel 2. The peripheral portions 13 and 16 of the two disks 12 and 14 are consequently inclined in the same direction, the peripheral edge of the pliable disk 12 engaging the peripheral edge at the conical inner surface 16a of the rigid disk 14.

The hub 11 has a recess 17 from which radial passages lead into the space between the two disks 12 and 14. Through some radial apertures 19 the hollow space of the shaft communicates with the recess 17 in the hub 11 so that liquid therefrom can enter the space between said disks.

The design of the other parts (not shown) of the apparatus is similar as in the form according to FIG. 1.

The action of the described apparatus is as follows: With the motor switched-on, the centrifugal disks 12 and 14 start to rotate with the shaft i. Incidentally, due to centrifugal action of the disks, liquid from the tank (not shown in FIG. 8) will be drawn into the hollow space of the shaft i and thrown out between the disks 12 and 14. On passage through the narrow gap between the peripheral edges thereof, the liquid is spread to a thin film. At the same time, the impeller (also not shown in FIG. 8) produces an air current through the channel e. The air current leaving the channel e blows across the liquid film in axial direction to said disks past the peripheral edges thereof, thereby breaking up the liquid film into tiny mist droplets which are carried oif in the air current and form an aerosol.

On rotation of the said disks, one disk 12 thereof will be resiliently deformed under centrifugal action so that the conical peripheral portion 13 tends to deflect outwards and towards the conical inner face 16a of the disk 14. The latter is of such rigid design that its peripheral portion 16 practically undergoes no deformation. As a result, at increasing speed of the shaft i, the peripheral edge of the disk 12 will be pressed with growing force against the peripheral edge of the disk 14. In this way the gap, through which the liquid film is thrown out between said disks will not be widened under centrifugal action as opposed to the previous forms of the apparatus. Consequently, even at high speed of the disks, the desired slight thickness of the liquid film will be maintained so as to ensure under all circumstances the production of adequately fine droplets.

Due to the fact that the conical peripheral portions 13 and 16 of the disks 12 and 14 are inclined towards the outlet gap of the air channel 2 and hence directed against the air flow, with adequately strong air current, a more powerful breaking action upon the liquid film and thus finer atomizing of the liquid will ensue than in the case of inverse inclination of the conical peripheral portions. Under actual service conditions it has been shown that for the atomizing action the relative velocity between the liquid and the air blown in is decisive.

It is understood that the foregoing description is given merely by way of illustration and that variations may be made therein without departing from the spirit of my invention.

What I claim is:

1. Apparatus for producing an aerosol mist, comprising a motor-driven blower for producing an air current, two centrifugal disks driven by the motor and having peripheral edges engaging each other, means to supply a liquid axially between said disks, said liquid being thrown out in a film between the edges of said disks, and means for guiding said air current axially over said peripheral edges of the disks for breaking up said film into mist drops, one of said centifugal disks being rigid and provided at its peripheral portion with a frusto-conical inner face, the other disk having'an elastically pliable frusto-conical peripheral portion substantially complementary to the frusto-conical inner face of said rigid disk, the conical portion of said other disk being arranged generally internally of the frusto-conical portion of said rigid disk, the peripheral edge of said other disk approaching the peripheral edge of said rigid disk due to centrifugal action to define therewith an annular aperture of diminishing size under increased speed of rotation.

2. Apparatus according to claim 1, wherein the conical peripheral portions are inclined toward the direction of the air current.

3. Apparatus according to claim 1, wherein the elastically pliable centrifugal disk consists of synthetic resin.

References Cited in the file of this patent UNITED STATES PATENTS 976,350 Ehrsam et a1 Nov. 22, 1910 1,803,067 Major et a1. Apr. 28, 1931 2,607,575 Hession Aug. 19, 1952 2,716,306 Lear Aug. 30, 1955 2,778,679 Lear Jan. 22, 1957 FOREIGN PATENTS 898,413 Germany Nov. 30, 1953

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