AU622771B2 - A foaming device - Google Patents

Description

i COMMONWEALTH OF AUSTRALIA All Patents Act 1952 COMPLETE SPECIFICATION

(ORIGINAL)

lass Int. Class Application Number Lodged Complete Specification Lodged Accepted Published Priority 6 March 1989 *,Related Art S'eName of Applicant S**Address of Applicant ,.,.Actual Inventor(s) *'.:*Address for Service MONTURAS S A :Guitard 43, 08014, Barcelona, SPAIN :Pedro Pares Montaner Pedro Castell6 Roig RICE CO., Patent Attorneys 28A Montague Street BALMAIN NSW 2041 SComplete Specification for the invention entitled: A FOAMING DEVICE The following statement is a full description of this invention including the best method of performing it known to us/me:- 1q- The invention relates to a foaming device, applicable to a delivery conduit of a spray member for a foamable liquid finely divided in the form of a divergent jet emerging from an outlet orifice of the delivery conduit, said foaming device being susceptible of being located in front of said orifice.

For many uses, parcicularly for the cleaning, washing and polishing of metal, wood, glass or of surfaces of other materials, it has been known for some time now to use spray members, such as spray guns for applying a fine dispersion of .00t5 an appropriate liquid on such surfaces.

It has become customary more recently to replace the said fine sprayed liquid dispersion with a foamed liquid.

Various solutions have been provided to face up to these new demands and they are usually based on the incorporation 30 of a foam generating device in a spray member.

One of such solutions is described in FR-2.429.614 where one of such generating devices is disclosed. The said device comprises, as a particularly important item, a grille mounted either in a frame or on the outer more open surface of a funnel-shaped arrangement. The sprayed liquid is forced through the grille and is thus foamed. This solution was an interesting contribution, although it suffers from the drawback that the grille and the frame or the funnel are made from different materials, making manufacture thereof more expensive. Furthermore the device in question frequently disperses the sprayed foam in an undesirable way.

EP-A-0 024 333 discloses a foam dispenser in which the liquid to be sprayed is forced through outlet orifices differentiated from one another by arms converging at the centre of the passage area and extending from one side to the other of the frame around the orifices. This dispenser lacks guiding means extending beyond the foam formation means, i.e.

beyond the said arms. Therefore, this dispenser also lacks 2 means for concentrating the foamed liquid.

The invention provides a device of the type indicated at the beginning with which the above drawbacks are overcome and the performance is improved. This device is characterised in that it comprises a tube having a first free outer open end and a second inner open end adapted to face said orifice, said second open end having a plurality of mutually non-contacting arms extending from the inner surface of the tube and having a free end, said arms being orientated generally inwardly towards the centre.

Preferably according to the invention said tube has a substantially cylindrical inner surface determining an ideal axis and the ratio of the height thereof to the inner diameter thereof lies between 1:1 and 3:1.

In a preferred development of the invention, there is a ,o first set of arms and a second set of arms. each arm of one 0 0,,0 of the sets being interspaced between two arms of the other set, with the arms of the first set being longer than the arms of the second set.

It is also contemplated that said arms are equidistantly eeoc spaced apart.

According to a further preferred feature of the invention, the inner surface of the tube is provided with short 0.: generally dihedral shaped protuberances situated between each pair of adjacent arms.

In a further development of the invention, the free end 0*0.

of each of said arms is provided on either side with a res- S pective divergent plane parallel to the axis of the inner cylindrical surface of the tube and furthermore each of said arms is provided, on the side facing the inner second open end, with a convex surface from which a bevelled surface leads to the corresponding free end.

Further advantages and features of the invention will be appreciated from the following description in which there is disclosed, without any limiting nature, a preferred embodiment of the invention with reference to the acompanying drawings, in which: Figure 1 is a partial elevation view of a soray gun 3 provided with the device of the invention, shown in cross section.

Figure 2 is a longitudinal section view, on a larger scale, of the device mounted on the spray gun.

Figure 3 is a view of the device looking towards the first outer open end thereof, showing also the rocking cover.

Figure 4 is a view of the device looking towards the second inner open end thereof.

Figure 5 is a cross section view along the line V-V of Figure 4.

Figure 6 is a view, on a large scale, of one of the arms 0 of the device, looking towards the free end thereof.

Figure 7 is a cross section view along the line VII-VII of Figure 6.

I 15 Figure 8 is a similar view to Figure 2, on a smaller S; scale, showing the out-of-service position of the device.

K The foaming device 2 of the present invention is for use in connection with a spray member 4 for foamable liquid.

such as a spray gun. Said member 4 is provided with known pumping means for the foamable liquid contained in a con- 1 tainer 6 to be sprayed in a finely divided form outwardly in a divergent jet, which emerges from the outlet orifice 8 of V a nozzle 10 which terminates the delivery conduit 12 of the S" liquid spray member 4.

The foaming device 2 is an integral unit and comprises Sessentially a tube 14 the inner surface 16 of which is prefe- .00 rably cylindrical, defining an axis 18. The tube 14 is S. provided with a first outer open end 20 and the second inner open end 22 which, in the operative position of the device 2, faces the orifice 8.

Said inner open end 22 has a plurality of arms 24, 26.

extending from the said inner surface 16 of the tube 14 and having a free end 28. Said arms 24, 26 do not contact each other and are orientated generally inwardly, i.e. radially towards the axis 18, but falling short thereof. Preferably said arms are equidistantly spaced apart.

There is preferably a first set of arms 24 longer than the arms 26 of a second set and each arm 24, 26 of one of the -4 sets is located between two arms 26, 24 of the other set.

With the said arrangement of the arms 24, 26, the second open end 22 has a major portion of the area thereof occupied by said arms, whereby a corresponding major portion of the divergent jet of foamable liquid emerging from the orifice 8 impacts against said arms, said liquid consequently becoming foamed.

To improve the interaction of the liquid and the arms, it is contemplated to provide low protuberances 30 on the inner surface 16 and said protuberances have a generally dihedral configuration, i.e. they have two flat surfaces converging in a sharp edge parallel to the axis 18 of the surface 16. Said dihedral protuberances 30 are preferably disposed between each pair of adjacent arms 24, 26.

5 Preferably (Figures 6 and the free end 28 of each p arm 24, 26 has two symmetrical flat lateral surfaces 32, each I of which is parallel to the axis 18 of the inner surface 16.

Furthermore the surface 36 on the side facing the second open end is convex and this convex surface 36 is connected to the e0 free end 28 by way of a bevelled surface 38. The configurl ation as described promotes the foaming of the liquid.

In turn, the tube 14 provides correct guiding of the I: already foamed liquid, as well as a substantial concentration of foam in the place to be treated, thereby avoiding undesired dispersions.

^The length of the tube 14 is preferably 1 to 3 times the inside diameter of the tube 14. Logically. the greater the ratio of said length to said diameter the greater will be the amount of liquid impacting against the inside of the tube before exiting from the first outer open end The impact of the liquid against the tube 14 causes various effects: in the first place said impact produces foam, which is the desired puroose; furthermore the said impact reduces the speed of the foamed liquid, which limits the range of the device, which may be a rather detrimental effect. Therefore, according to the characteristics of the jet provided by the nozzle 10, the characterfistics of the liquid to be foamed and even the features of the service it is desired to obtain, a tube having the most appropriate length/diameter ratio in the light of previous test results will be used, in each case.

The said tube 14 crosses through a rocking cover 40 hingedly attached to a nozzle holder 42. The cover may be fixed in the foaming position of Figures 2 and 3 by known means, such as for example a tab 44 of the cover 42 held between two protuberances 46 of the spray gun 4. On passing to the outof-service position of the device (Figure the cover 42 is retained in said position as a result of the so-called memory of the plastics material.

To facilitate the placing of the device 2 in the foaming position, the tube 14 is provided with a wider diameter portion 48 facilitating a press fit in the nozzle holder 42, which is provided with passages 50 to allow air to accede to the space between the nozzle 10 and the second inner open end 22.

Preferably the arms 24, 26 are spaced between 0.3 and mm from the orifice 8. In turn, the said arms are preferably 0 .40 from 0.3 to 1 mm wide.

o•

Claims (7)

1. A foaming device, applicable to the delivery conduit of a spray member for a foamable liquid finely divided in the form of a divergent jet emerging from an outlet orifice of the delivery conduit, said foaming device being adapted to be located in front of said orifice, characterised in that it comprises a tube having a first free outer open end and a second inner open end adapted to face said orifice, said second open end having a plurality of mutually non-contacting arms extending from an inner surface of the tube and having a free end, said arms being orientated generally inwardly towards the centre.

2. The device of claim 1, characterised in that said tube has a substantially cylindrical inner surface and the ratio of the inner diameter to the length thereof is between 1:1 and 1:3.

3. The device of claim 1 or 2, characterised in that i: I S"there is a first set of arms and a second set of arms each 20 arm of one of the sets being interspaced between two arms of the other set, with the arms of the first set being longer than the arms of the second set.

4. The device of any one of claims 1 to 3, characterised in that said arms are equidistantly spaced apart.

5. The device of one of claims 1 to 4, characterised in :that the inner surface of the tube is provided with short generally dihedral shaped protruberances situated between each pair of adjacent arms.

6. The device of any one of claims 2 to 5, characterised in that the free end of each of said arms is tapered having side surfaces which lie in planes which are parallel to the longitudinal axis of the inner cylindrical surface of the tube. TL~b 4 Dorz n

7 The device of any one of claims 2 to 6, charac- terised in that each of said arms is orovided, on the side facing the inner second open end, with a convex surface from which a bevelled surface leads to the corresponding free end Dated this 26 day of February 1990 MONTURAS S A S* Patent Attorneys for the Applicant SF.B. RICE CO. i 0 I :i