US3053458A - Apparatus for producing an aerosol - Google Patents

Description

Sept. 11, 1962 K. FLURY 3,053,458

APPARATUS FOR PRODUCING AN AEROSOL Original Filed April 25, 1958 2 Sheets-Sheet 1 Fig. 1

Sept. 11, 1962 K. FLURY 3,053,458

APPARATUS FOR PRODUCING AN AEROSOL Original Filed April 25, 1958 2 Sheets-Sheet 2 d Fig.3 6

ATTORNEYJ' States Patented Sept. 11, 1962 Free 3,053,458 APPARATUS FOR PRODUCWG AN AEROSOL Karl Flury, Zurich, Switzerland. assignor to Defenser A.G., Zurich, Switzerland Original application Apr. 25, 1958, Ser. No. 731,014, now Patent No. 3,004,717, dated Oct. 17, 1961. Divided and this application Aug. 14, 1961, Ser. No. 131,124 6 Claims. (Cl. 239-216) 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.

This application is a division of application Serial No. 731,014 filed April 25, 1958, now Patent No. 3,004,717.

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:

FIGURE 1 shows partly in elevation and partly in longitudinal section a first form of embodiment of the apparatus according the invention;

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

FIGURE 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;

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

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

The essential constructional features and advantages of the apparatus shown in FIGURE 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 e of circular cross section gradually decreasing towards and opening at top in FIGURE 1.

A rear casing part 1 is detachably secured to the forward casing part d by means of screws g. The said two casing parts having clamped therebetween the peripheral margin of a circular air baffle plate h. The rear end of the motor-shaft i carries an impeller k of the centrifugal action-type which is arranged between said baffie plate It and the internal casing part b. The rear casing part 7" has openings for the intake of air which is then forced by the impeller into the channel 2 and blown out through a circular gap at the forward end of the casing. As apparent from FIGURE 1, the channel e 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 fiows in axial direction of the disks 1 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 l. The forward end of the hollow shaft i is sealed by a screw m, whereas the rear end thereof communicates with a liquid tank 11. 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 it into the hollow space of the shaft i. The rear end of the shaft i carries a hub u having a slip ring v. A flange ring y joined to the bellows t has a slip ring x which bears against the slip ring 11 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 knobb coaxial to the knob a 'has an abutment c for the knob 11'. 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 difiicultly than the knob a. 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 n is secured against the lower part of the housing 1 by means of diametrically opposite tension levers e 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 It 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 m 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 11, each of which being offset twice in opposite directions. One elbow 0' of each limb can rest against the rear casing part 1, as shown in FIGURE 1.

With shaft i rotating and valve r 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 l, 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 I 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 a, whereupon the baffle plate h 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 The knob a allows setting of the amount casing part b together with motor, impeller and disks can be withdrawn rearwards from the casing part d. The vanes thereby serve for guiding the part b in the part d. In service condition of the apparatus, the vanes 0 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 11 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 11 removed from the casing part 1, the liquid to be atomized may be, if necessary, sucked up by means of a hose 0 or directly out of another container, say, a canister. If the supporting member n 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 FIGURE 2 is distinguished from that described by the fact that only a single centrifugal disk p is provided instead of two disks I. 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 etficiency of the form according to FIG- URE 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 oh the lamellae in the desired direction.

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

According to FIGURE 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 inner space of the hollow shaft i. A spacer 3 provided with radial passages is interposed between the disks l. One disk l 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 in 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 a and extend to the outer casing part d. From FIGURE 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 1 if no air would flow through the channel 2. 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 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 1 can be thrown out between the lamellae 7.

The other parts of the apparatus, not illustrated in FIG- URES 3 and 4, are designed similarly as in the form according to FIGURE 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 FIGURE 4. Incidentally, by the centrifugal action of the disks, liquid from a tank (not shown in FIGURE 3) will be drawn into the hollow space of the shaft i and thrown out between the disks l, 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 FIGURE 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 off in the air flow and form an aerosol, as shown at A in FIGURE 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 FIGURE 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 FIGURE 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 off to form the mist rays B.

In the form according to FIGURE 6, the lamellae 7b are likewise given a thin wedge end 8 which, however, due to inverse sloping end limitation of the lamellae is new disposed more inside. Another difference of the form according to FIGURE 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 gap.

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 is claimed is:

1. Apparatus for producing an aerosol mist, comprising a motor-driven blower for producing an air current, two motor-driven centrifugal disks with peripheral edges engaging each other, means to supply a liquid axially between said disks, said liquid being thrown out in a film between the peripheral edges of said disks, means for guiding said air current axially over said peripheral edges of the disks for breaking up said film into mist droplets, and a ring of spaced stationary lamellae arranged around said peripheral edges of the disks in spaced relation and in the path of said mist droplets and in the air current, wherein a casing is provided for the blower and having an annular outlet gap for discharging said air current, said lamellae being arranged with one end engaging in said gap and with the other end protruding outside said casing.

2. Apparatus according to claim 1, wherein an annular member is provided with the lamellae provided thereon which rests on one of the Walls defining the outlet gap.

3. Apparatus according to claim 1, wherein a casing is provided in which the outlet gap is subdivided by an annular member into an inner and an outer section in one of which the lamellae engage.

4. Apparatus according to claim 1, wherein the lamellae are disposed substantially at right angles to the moving direction in which the liquid droplets would be drawn off the edges of the centrifugal disk in the absence of the air current.

5. Apparatus according to claim 4, wherein the lamellae are disposed with respect to each other in such a Way 6 as to overlap each other transversely to the direction in which the liquid droplets are thrown ofi the edges of the centrifugal disks in the absence of the air current.

6. Apparatus according to claim 1, wherein said other end of each lamellae has a sloping surface.

References Cited in the file of this patent UNITED STATES PATENTS 2,607,571 Hession Aug. 19, 1952 10 2,607,574 Hession Aug. 19, 1952 FOREIGN PATENTS 523,157 Canada Mar. 27, 1956

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