EP0703739B1 - Aerosol-foam dispenser head - Google Patents

Abstract

PCT No. PCT/EP94/01853 Sec. 371 Date Feb. 2, 1996 Sec. 102(e) Date Feb. 2, 1996 PCT Filed Jun. 7, 1994 PCT Pub. No. WO94/28759 PCT Pub. Date Dec. 22, 1994An aerosol-foam dispenser head is mounted on a container which holds a solution of an active substance and an insoluble, gaseous propellant, and which opens a valve in the container when actuated. The dispenser head has, at the near end of its outlet channel, a throttled aperture with a relatively small flow cross section. Located in the wall of the channel, downstream of the aperture is at least one opening connecting with the atmosphere, the cross section of the opening being significantly greater than that of the throttled aperture. Located at the far end of the channel is a fine-mesh grating or screen.

Description

The invention relates to a dispenser head for a foam aerosol according to the preamble of claim 1.

Foam aerosols are used, for example, in the household for cleaning carpets, tubs or the like, or also in the field of cosmetics for hair and body care. It is known to drive out the active substances for such aerosol foams with hydrocarbons and fluorinated chlorinated hydrocarbons. Fluorinated chlorinated hydrocarbons are increasingly rejected for environmental reasons. Hydrocarbons are flammable and therefore not harmless.

Compressible gases such as nitrogen or compressed air can be considered as safe blowing agents. While hydrocarbons dissolve in liquid active substances, this is not the case with nitrogen or compressed air. It is therefore difficult to use the pressure with such propellants Keep consumption of the active ingredients at a sufficient level in order to obtain an effective spray. Moreover, it is difficult with such pressure media to obtain desired aerosol foams in conventional valve-dispenser head combinations.

From US-A-5 054 688 a foam forming apparatus using a venturi has become known. Water is supplied to the nozzle centrally, while air is supplied via three circumferential side holes that open into the narrow area of the nozzle. In connection with such a Venturi nozzle it is also known to connect a tube to the nozzle in which a sieve is attached.

From US-A-5 085 371 a device has become known in which two throttle openings are arranged one behind the other in an elongated tube, the second having a larger cross section than the first and in which a diffuser with a sieve is arranged directly behind the second throttle opening . Such a device is used for fire extinguishers for foam formation.

From GB-A-2 024 049 a dispenser head of the type mentioned at the outset has become known, which can be placed as a one-piece component on a package containing an active substance solution, the component having a throttle opening of relatively small cross-section at the front end of a flow channel. In the wall of the flow channel behind the throttle opening there is at least one opening connected to the atmosphere, the cross section of which is significantly larger than that of the throttle opening. A fine-meshed grid or sieve is arranged at the rear end of the channel.

The invention has for its object to provide a dispenser head for a foam aerosol, with which liquid-insoluble propellant gases are effectively produced while maintaining sufficient propellant pressure at the end of the delivery of the active substance.

This object is achieved by the features of claim 1.

In the dispenser head according to the invention, an inner channel section is provided for receiving a tappet of a valve of a package containing a non-soluble gaseous propellant, the channel section having a throttle opening. The channel section is connected via a plurality of webs which are arranged at a distance in the circumferential direction to the interior of a hat-shaped or cap-shaped section which surrounds the channel section at a distance and to which the tubular flow channel is molded. The opening is formed between the webs and the cap-shaped section is sufficiently spaced from the side of the cap.

Particularly advantageous in the invention is the design of the one-piece head, in which the openings through which air is sucked in ejector-shaped are moved into the interior of the head, so that there is no impairment due to contamination or the like. In addition, due to the special type of application of the cylindrical section, the openings formed by the webs are placed very close to the throttle opening, so that intensive swirling can take place to form an effective and fine foam with the aid of the sieve at the end of the tubular channel.

According to one embodiment of the invention, a conical is at the transition of the cap-shaped section to the flow channel tapered passage is provided, and the webs are connected to the conical wall. In this way, the ejector effect comes about satisfactorily.

Four webs are preferably provided. According to another embodiment of the invention, they are formed on the outside of the channel section and gradually widen in the direction of the cap-shaped section.

In the dispenser head according to the invention, a throttle opening with a relatively small cross-section follows in the flow path behind the conventional valve for the aerosol pack. According to one embodiment of the invention, the cross section can have 0.2 to 1.5 mm, preferably approximately 0.6 mm. These diameters depend to a large extent on the nature of the substance to be foamed. As a result, the liquid active substance flows through the throttle opening at a relatively high speed and tears outside air from the lateral opening in the wall of the flow channel, which leads to the swirling and foaming of the active substance. According to an embodiment of the invention, the swirled and air-enriched jet can meet a sieve which is arranged at the end of the channel, as a result of which a compact foam or a surface foam emerges, depending on the distance to the object to be sprayed. According to a further embodiment of the invention, the sieve can preferably have a mesh size of less than 0.2 mm.

According to one embodiment of the invention, the sieve can be molded into a ring made of plastic, which is then inserted into a recess at the upper end of the channel section. The one-piece production of a sieve with A plastic ring or the like in the injection molding process is easily possible with conventional techniques. Alternatively, a sieve or the like can be attached to the end of a sleeve, which can then be fitted like a hat onto a hollow cylindrical pin which delimits the lower part of the flow channel and has the opening (s).

Fig. 1

zeigt einen Schnitt durch einen Spenderkopf nach der Erfindung.

Fig. 2

zeigt eine Draufsicht auf den Spenderkopf nach Fig. 1.

Fig. 3

zeigt vergrößert das obere Ende des Spenderkopfes nach Fig. 1 in abgewandelter Form.

The invention is explained in more detail below with reference to an embodiment shown in the drawings.

Fig. 1

shows a section through a dispenser head according to the invention.

Fig. 2

shows a plan view of the dispenser head of FIG. 1st

Fig. 3

shows enlarged the upper end of the dispenser head of FIG. 1 in a modified form.

The dispenser head 50 according to FIG. 1 is designed as a one-piece component 52 and is made of plastic material. It has a lower hat-shaped or cap-shaped section 54 and an upper sleeve-shaped or tubular section 56.

In section 54 there is a hollow cylindrical extension 58 which interacts with a valve (not shown) of an aerosol pack onto which the dispenser head 50 is placed. For example, lug 58 may interact with the tappet of an aerosol valve.

The transition from the interior of the cap-shaped section 54 to the channel 60 of the tubular section 56 is conical, as shown at 62. On the wall of the conical section 62 are four webs 64 arranged at the same distance, two of which can be seen. The webs 64 extend down to the outer wall of the tubular extension 58, whereby it is attached to the tubular section 56. The webs form openings 66 between them, through which air can flow along arrows 68.

The tubular extension 58 is closed at the upper end by a wall 70 in which a throttle opening 72 is provided, for example with a diameter of 0.6 mm.

The dispenser head 50 is used to dispense aerosol foams, such as those used for cleaning carpets and tubs or in the cosmetics sector. The corresponding active ingredient (a surfactant solution) is filled in a conventional aerosol pack and is under the pressure of a water-insoluble propellant, such as air or nitrogen. If the aerosol valve is opened by finger actuation of the dispenser head 50, active substance flows through the throttle opening 72 under pressure, air is thereby entrained within the cap-shaped section 54 and also flows into the channel 60. At the upper end of the sleeve section 56 according to FIG. 3, an annular recess can be formed 29 can be provided which receives a plastic ring 30 which is formed together with a fine-meshed sieve 32. For example, the sieve has a mesh size of preferably 0.2 mm or less and is made of plastic or metal.

As can be seen from FIG. 2, on the outside of the cap-shaped section 54 a pair of opposite wings 76 can be seen, the upper side of which also has a cross section triangular grooves that lie on a circular arc is provided. The wings 76 serve to grasp the dispenser head 50, for example with the index and middle fingers, in order to press the dispenser head 50 against the packaging and to actuate the aerosol valve (not shown).

Claims (9)

1. A dispensing head for a foam aerosol comprising a one-piece component (50) which is designed to be mounted on a pack containing an active substance solution, the component (50) comprising a flow restriction opening (72) of relatively small cross-section at the front end (looking in the direction of flow) of a flow passage (60), at least one opening (66) communicating with the atmosphere being provided in the wall of the flow passage behind the flow restriction opening (72), the cross-section of the opening (66) being distinctly larger than that of the flow restriction opening (72), and a fine-mesh sieve or wire being arranged at the rear end of the passage (60), characterized by the following features:

   - an inner passage section (58) for receiving the stem of a valve of a pack containing an insoluble gaseous propellent;

   - the passage section (58) comprises the flow restriction opening (72);

   - the passage section (58) is connected by several webs (64,66) peripherally arranged at intervals to the interior of the hat- or cap-like section (54) which surrounds the passage section (58) with a space in between and in which the tubular flow passage (60) is formed;

   - the opening (66) is formed between the webs (64) and

   - the cap-like section is at a sufficient distance from the top of the pack.
2. A dispensing head as claimed in claim 1, characterized in that the transitional zone from the cap-like part (54) to the flow passage (60) is provided with a conical aperture (62) and the webs (64) are connected to the conical wall.
3. A dispensing head as claimed in claim 1 or 2, characterized in that four webs (64) are provided.
4. A dispensing head as claimed in any of claims 1 to 3, characterized in that the webs (64) are formed on the outside of the channel section (58) and gradually widen towards the cap-like section (54).
5. A dispensing head as claimed in any of claims 1 to 4, characterized in that the flow restriction opening (24) has a diameter of 0.2 to 1.5 mm and preferably of the order of 0.6 mm.
6. A dispensing head as claimed in any of claims 1 to 5, characterized in that the wire (32) is formed in a ring (30) of plastic which is placed in a recess (28) at the upper end of the passage section (16).
7. A dispensing head as claimed in claim 6, characterized in that the ring is held in the recess by a press fit.
8. A dispensing head as claimed in any of claims 1 to 7, characterized in that the sieve is arranged at the end of a sleeve mounted on a hollow cylindrical projection of the component comprising the lateral openings and the flow restriction opening.
9. A dispensing head as claimed in any of claims 1 to 8, characterized in that the wire or sieve (32) has a mesh width of less than 0.2 mm.

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