WO2005070313A1

WO2005070313A1 - Microdermabrasion device

Info

Publication number: WO2005070313A1
Application number: PCT/GB2004/002908
Authority: WO
Inventors: Philip Ball
Original assignee: Crystal Clear International Limited
Priority date: 2004-01-21
Filing date: 2004-07-05
Publication date: 2005-08-04
Also published as: GB0415034D0; EP1706048A1; GB2410191B; GB0401550D0; GB2410191A

Abstract

The present invention relates to a microdermabrasion device for skin treatment (1) comprising: a handset housing a nozzle head (5) and having handle means for manipulating the handset; a nozzle (16) in the nozzle head for supplying a stream of micro-particulate material to the skin surface in use of the device; a headspace around the nozzle, separating the nozzle from an outlet port in the handset which contacts the skin in use of the device; means for pulling a vacuum in the headspace; means for withdrawing debris from the headspace and away from the handset, the nozzle communicating at its downstream end with the headspace and at its upstream end with a flow line having at least two limbs, a first limb communicating in use of the device with the atmosphere, and a second limb communicating in use of the device with a reservoir of micro-particulate material, the first and second limbs being arranged with respect to each other such that the pulling of a vacuum in the headspace when the outlet port is positioned against the skin surface causes an airflow from the atmosphere to the headspace through the first limb of the flow line, and causes material from the reservoir to be drawn into the flow line by means of a venturi effect at the junction of the first and second limbs of the flow line.

Description

MICRODERMABRASION DEVICE

The present invention relates to a device for microdermabrasion. The present invention also relates to the field of skin treatment and to improvements in an apparatus for carrying out micro-abrasion, in particular microdermabrasion and more particularly to provide improvements to the handset used to carry out microdermabrasion, its construction and use in hygienic skin treatments without anaesthetic.

The treatment of skin tissue by means of microdermabrasion, that is to say the bombardment of the skin with a stream of small particles, has long been recognised to have improving effects on the skin and this technology has found application in both medical and cosmetic contexts.

A number of devices are well known in the art for use in aesthetic applications in the field of skin treatment. These devices include devices used for abrasively removing layers of human skin in such a way as ultimately to obtain aesthetic improvements to the skin being treated. Depending on the application and the desired end result, such superficial skin abrasion may range from a light abrasion, where the outermost layers of the epidermis are removed, to a much deeper abrasion, where the dermis is involved.

Treatment with such devices is termed a microdermabrasion procedure and may be used to remove the epidermal skin layer, or selected portions of the epidermal skin layer, such as the stratum corneum. Removal of all or selected portions of the epidermal layer from a treatment area may stimulate underlying skin tissue, which may in turn serve the desirable outcome of freshening or toning the skin.

A microdermabrasion procedure may also be used to remove portions of the dermal skin layer from a treatment area. Removing portions of the dermal skin layer may remove undesired skin pigmentation or blend the colour of the treatment area more closely to match the skin pigmentation of adjacent skin. A microdermabrasion procedure may be used to freshen or tone the skin, to treat wrinkles, such as ageing wrinkles, to treat stretch marks, and/or to treat skin blemishes. Skin blemishes which may be susceptible to microdermabrasion treatment include, but are not limited to, certain forms of keratoses, acne, scar tissue, calluses, melasma, hyper- pigmentation, photo- or sun- damaged skin, and tattoos.

During a microdermabrasion procedure, the hand piece of a microdermabrasion apparatus may be guided over a treatment area. One type of microdermabrasion machine depends on an oscillating abrasive tip or platform to remove skin tissue (US-A-6241739 and US-A6283978). Some prior art machines use vacuum suction to remove debris (US 2003060834). In other microdermabrasion techniques, abrasive particles are projected from a supply receptacle across the treatment area using compressed air or gas. The particle may abrade and remove portions of the skin, and a vacuum may be used to draw the abrasive particles and removed skin into a waste receptacle. The vacuum may typically range from about 10cm to about 50cm of mercury, and stretch the skin causing local vasod ilatation.

The use of compressed air or gas to propel the abrasive particles against the skin, and a vacuum line to remove them and any debris from the skin, is common to microdermabrasion machines of the prior art (for example US-A-5810842, US-A-5037432 and GB-A-2319480).

US-A-5037432 describes an apparatus which is used to remove surface portions of human tissues in an adjustable manner, and essentially comprises a tool provided with a supply tube along which abrasive reducing substances (particles) are propelled under pressure. A through- hole in the head disposed along the axis of the tube permits the substances to abrade the region of tissue facing the hole. A collection tube in which is created a depression is provided for the purpose of removing under suction both the reducing substances, and the portions of tissue removed during the treatment. This apparatus employs both a compressed gas and a vacuum line. GB-A-2319480 also involves a combination of compressed gases and vacuum to project abrasive particles at the skin, and remove used abrasive and skin debris from the treatment area. US-A-659259 is designed for microdermabrasion and suction massage and uses exclusively a vacuum supply to perform both functions, back- flushing being carried out by connecting various portions of the unit to a pressurised output of the source of vacuum.

EP-A-0324448 discloses device for making micro-abrasions, particularly on human tissue, which includes a handle having an aperture that is intended to be positioned on the surface to be treated, and means for the metered supply of reducing substances in a pneumatic carrier to the aperture of the handle. The supply means comprises only a vacuum source.

US Patent No. 5810842 discloses a device for microdermabrasion using a flow of a mixture of air and reducing substances, the device comprising a casing with a vacuum pump and a compressor at an interior of the casing. The device further comprises a control footswitch for actuating the compressor, a mixing bulb and a collecting bulb at an exterior of the casing, and a hand piece extending between the mixing bulb and the collecting bulb.

WO-A-97/11650 describes an device for microdermabrasion comprising a first container for unused micro-crystals, a second container for used micro-crystals, a handset provided with a delivery aperture for delivering unused micro-crystals to skin and for receiving used micro-crystals and skin debris, and second means adapted to withdraw used crystals from the skin via a vacuum inlet.

WO-A-99/23951 discloses a device for making micro-abrasions including a handle having an inlet passage and an outlet passage communicating with an aperture in said handle. The aperture in use is adapted to be positioned on a surface to be treated, such as the skin, and a pneumatic means provides a variable supply of abrasive particles to the aperture of the handle. The pneumatic means includes a vacuum source having a suction outlet that is operatively connected to the outlet passage of the handle and an exhaust outlet that is operatively connected to the inlet passage of the handle, thereby to cause the abrasive particles from the supply container to flow through the handle.

EP-A-0992221 discloses a particle beam flow abrasion system including machinery for creating a vacuum and positive pressure.

United States Patent No. 6562050 discloses a hand piece for use in a microdermabrasion system, the hand piece including a control line that allows the user to control activation of the compressor, a vacuum line and a compressor line. The microdermabrasion system includes a vacuum pump, compressor and a mixing bottle. A pressure sensor is used to detect pressure changes in the system for use in activating/deactivating the compressor. Prior art microdermabrasion devices suffers from one or more of the following disadvantages: they are bulky and/or of complex construction and/or have a plurality of lines connecting the nozzle or handle with the rest of the device comprising the vacuum pump, compressor and/or micro- particle reservoir; they do not provide the user with good control over the micro-particle flow, or else control of micro-particle flow is only achieved by complex and/or costly means; the device is difficult to keep sterile and/or clean, particularly when recharging the micro-particle reservoir.

One particular drawback of certain prior art systems is that the sterility of the various components in the microdermabrasion apparatus is difficult to ensure, without the use of complicated and expensive processes. US-A- 6322568 describes an attempt to overcome the problems of lack of guaranteed sterile conditions. The apparatus disclosed comprises a compressor, a vacuum pump, and three detachable one-piece components, including a mixing bottle, a collecting bottle for the abraded particles, and a hand piece to touch the tissue to be treated. These components are preferably made of glass or plastic material and can be easily sterilised. Potential drawbacks of such an apparatus include the fact that the air pressurisation is performed by a compressor placed inside the apparatus, making it necessary to sterilise the air in the system to avoid the compressor being infected by bacteria which would eventually be conveyed onto the patient's skin, during treatment, by the pneumatic system. While the above-mentioned one-piece components may be sterilised after the apparatus has been used, this reduces the utilisation of the apparatus significantly. A further drawback is that contamination can occur when the mixing bottle is filled with new abrasive particles, or when the collecting bottle is emptied.

Although some apparatus in the prior art are provided with an optional foot pedal which is adapted to enable a higher pressure or more intensive effect when in use, generally existing designs do not allow for significant flexibility of use, or ease of control. Thus, skin-treatments which can be administered are limited, or at least difficult to vary in a controlled manner. Furthermore, as soon as the treatment aperture is removed from the skin, microdermabrasion particles tend to scatter from the aperture until the apparatus is completely switched off, or the vacuum pump and/or air compressor have run down after being switched off.

It is an object of the present invention to overcome or ameliorate one or more of the aforesaid disadvantages. It is therefore an object of the present invention to provide an improved form of microdermabrasion device. In particular, it is an object of the present invention to provide a microdermabrasion device which is not bulky or difficult to use, which is not encumbered by a multiplicity of flow lines, which comprises means for controlling micro-particle flow, and which is relatively easy to keep clean and/or sterile, in particular when recharging or changing the micro-particle reservoir.

Accordingly, and from the point of view of a beauty salon, where the recipient of such a microdermabrasion treatment is expecting a relaxing experience, all the prior art devices possess drawbacks, which can be generalised to the following areas:

• Apparatus is bulky and ergonomically difficult for a beauty technician to manipulate/control. • Control of abrasive emission is inconsistent, with slow and variable response to controls.

• Sterile operating conditions are difficult to achieve, making a hygiene guarantee difficult.

Therefore, it would be useful to provide a simple, user friendly device which enables a controlled and adjustable removal of superficial skin surface by the projection of an abrasive stream onto the skin surface under sterile conditions.

According to the present invention, there is provided a microdermabrasion device for skin treatment comprising:

• a handset housing a nozzle head and having handle means for manipulating the handset; • a nozzle in the nozzle head for supplying a stream of micro- particulate material to the skin surface in use of the device;

• a headspace around the nozzle, separating the nozzle from an outlet port in the handset which contacts the skin in use of the device;

• means for pulling a vacuum in the headspace;

• means for withdrawing debris from the headspace and away from the handset, the nozzle communicating at its downstream end with the headspace and at its upstream end with a flow line having at least two limbs, a first limb communicating in use of the device with the atmosphere, and a second limb communicating in use of the device with a reservoir of micro- particulate material, the first and second limbs being arranged with respect to each other such that the pulling of a vacuum in the headspace when the outlet port is positioned against the skin surface causes an airflow from the atmosphere to the headspace through the first limb of the flow line, and causes material from the reservoir to be drawn into the flow line by means of a venturi effect at the junction of the first and second limbs of the flow line.

The microdermabrasion device of the invention has a number of significant advantages in relation to prior art devices and systems. The transfer of material from the reservoir to the skin surface is effected by means only of a vacuum in the headspace. The invention does not require the use of a separate compressor. Rather, the invention is operable simply by connection of the headspace to a vacuum line. The absence of a compressor in the device of the invention means that the device is relatively small compared to some prior art devices, and is relatively easier to manipulate, both due to its size and the absence of any compressor line. It should be appreciated that the device of the invention is intended primarily for use in cosmetic applications and, in particular, in beauty salons and the like. Space and manoeuvrability are important considerations in such business environments, and so the absence of a compressor provides a significant advantage in this respect.

The device of the invention also has the advantage that the flow of micro- particulate material is easily controlled by the user. This could of course be achieved by controlling the strength of the vacuum pulled in the headspace by means of the vacuum pump setting or some other suitable controller. However, advantageously, the micro-particulate material flow can be controlled simply by lifting the outlet port from the skin surface. Slight such lifting will decrease the flow of micro-particulate material, and complete removal of the outlet port from the skin surface will dramatically reduce the flow, or shut the flow off altogether, as the vacuum pulled in the headspace will simply draw air in through the outlet port, and the venturi effect between the first and second limbs will be minimal or non-existent as the air flow in the first limb is reduced or stopped. When the outlet port is placed against the skin surface, it is also possible to control to some extent the micro-particulate material flow by partially closing the communication between the first limb of the flow line and the atmosphere, for example by placing a finger (or other closure means, possibly connected to the device) over a part of the flow line first limb end. However, in order for highly satisfactory control in this regard to be achieved, it is desirable to provide a second point of communication between the flow line and the atmosphere.

Accordingly, the invention provides a microdermabrasion device as described hereinabove, wherein the flow line is provided downstream of the second limb with a third limb communicating with the atmosphere.

By having first and third limbs communicating with the atmosphere respectively upstream and downstream of the connection between the second limb and the first limb, the user is provided with an even greater degree of control over the micro-particulate material flow in the device of the invention simply by using a finger (or other closure means) to close or partially close the first or third limb from the atmosphere.

Although in most practical situations it is envisaged that the user will manually close the connection between the first or third limb and the atmosphere, it is of course within the scope of the invention that mechanical or other means could be provided to make a more controlled or measurable closure possible, thereby effecting even greater control over the micro-particulate material flow. Such mechanical means may comprise, for example a lever or piston operated closure means.

Preferably, the third limb is of larger average cross section than the first limb in the region upstream of the third limb. In that case, when both first and third limbs are communicating with the atmosphere (with the device of the invention operational but in standby mode) the resulting airflow occurs mainly via the third limb, thus minimising or preventing the flow of air in the first limb upstream of the third limb which would otherwise cause particulate material to be drawn through the second limb of the flow line by a venturi effect. When the third limb is closed to the atmosphere air is then drawn from the atmosphere through the first limb, and the resulting venturi effect at the junction of the first and second limbs causes particulate material to flow in the device.

In order to achieve optimum venturi effect, it is preferable that the second limb of the flow line be at least approximately perpendicular to the first limb at the point where first and second limbs join.

It is also preferred that the first limb be provided with a constriction in the region of or at the point where the first and second limbs join in order to achieve optimum venturi effect. The headspace around the nozzle head is conveniently provided by means of a shroud covering the nozzle head and having within it an outlet port for contacting the skin in use of the device. In some embodiments of the invention, for example for treating larger areas of the body, the nozzle head may be provided with more than one nozzle, and the outlet port may be enlarged, and may have dimensions commensurate with, larger than, or only slightly smaller than, the area circumscribed by the plural nozzles.

In use of the device the second limb of the flow line communicates with a reservoir of micro-particulate material. Preferably, the reservoir is closed except for its point of communication with the flow line. This communication may be by means of a line connecting the handset with a separate reservoir. However, preferably the handset is provided with means for mounting a suitable reservoir of micro-particulate material.

Because the device of the invention relies only on a vacuum source, and not on a separate compressor, to withdraw particulate material from the reservoir, there arises another significant advantage of the invention, namely that the reservoir can be provided in sealed (if necessary hermetically sealed) form with a single openable or puncturable port for connecting to the second limb of the flow line. When one container has been emptied, it can simply be removed and replaced with another. The present invention relies exclusively on a source of vacuum to create a closed airflow which picks-up inert abrasive particles housed within a simple device before the air/abrasive particle mixture thus created is caused to impinge on a targeted surface immediately beneath an aperture in a shroud which confines the emerging air/abrasive particle mixture stream, and encloses an outlet for a vacuum line along which the abrasive particles, after impact on the targeted surface, and any surface debris created by the impacts, are recovered by the same air stream that impinged upon the skin and are subsequently extracted by passage through filters prior to being exhausted to ambient. The abrasive particles are introduced to the system from a sealed single treatment container inserted in a docking port within the device and replaced after each treatment. The abrasive is only caused to drawn into the airflow when the shroud of the device is pressed onto the surface to be treated, effectively closing the air-flow system. The filter for the exhaust air stream may be housed with the vacuum pump in a remote cabinet. The invention is hygienic and extremely easy to control by the operator. When used in the microdermabrasion process the apparatus of the invention can be used without anaesthetising the patient.

DESCRIPTION OF DRAWINGS

The invention will be now be more particularly described with reference to the following drawings: Figure 1 shows a simplified schematic diagram of a microdermabrasion device in accordance with the invention;

Figure 2 shows in more detail the interior arrangement of the device shown in of Figure 1 ;

Figure 3 shows the device of Figures 1 and 2 in operation against the surface of a skin tissue, and depicts the air flow in the device in use; and#

Figure 4 shows an alternative nozzle arrangement for treating larger areas.

DETAILED DESCRIPTION OF THE INVENTION In more detail, Figure 1 shows the major desirable component parts of the invention in a schematically simplified form, comprising a vacuum pump (9) and filter/used abrasive container (8), remotely connected to a device (1 ) containing an abrasive container (2) by a flexible vacuum line (6). Figure 2 shows a cross section of one possible arrangement of the airways within the device. A channel (11 ) runs along the body of the device with outlets to atmosphere at points (12) and (13) and through the nozzle (16) in the head (5) of the device, where it protrudes centrally from the head (5) directly opposite the aperture (4) in the nozzle shroud (3). The size of outlet (12) is larger than that of outlet (13) and contains a course mesh filter to guard against abrasive particle escape. Channel 10 runs from the abrasive container docking port (15) to join with channel (11 ) between outlets (12) and (13). A separate channel (7) runs from the face of the device head (5) to a junction on the lower surface of the device where it connects with a flexible vacuum connection to the remote filter/abrasive collecting unit which in turn is connected to the vacuum pump. Figures 3a and 3b both show in cross section the shroud (3), which is an air-tight push fit, placed around the device head (5) to create a potentially air-tight chamber (14) with a single aperture (4) directly opposite the outlet of the nozzle (16), which is at the end of channel (11 ) protruding from the face of the head (5). Figure 3a shows the situation when the device (1 ) is held away from the surface and shroud aperture 4 remains open. Any vacuum applied to the chamber (14) via channel (7) will be dissipated via the aperture (4) in the shroud (3). Figure 3b shows the situation when the device (1) is held against a surface and the shroud nozzle (4) is effectively sealed creating an air tight chamber (14) around the nozzle (16). Any vacuum applied to the chamber (14) via channel (7) will cause an air flow along channel (11) drawn from outlets (12) and (13). Figure 4 shows an alternative form of the shroud (3) in cross section. This form of shroud is designed to diffuse the stream of abrasive particles projected onto the surface.

The apparatus of the present invention may be used with various fluid and transported media to etch, polish, abrade, clean or colour various surfaces including superficial areas of the human body. To improve the readers understanding of how it works an embodiment of the invention in which it is used to mildly abrade human skin tissue and remove debris, improve the appearance of the skin and stimulate healthy cell growth, a process known as microdermabrasion, will now be described in detail. The device exemplified in figures 1 to 3 is self-contained with the exception of a source of vacuum and an associated filter, which may be of microbiological grade, to isolate all debris resulting from the abrasion of skin tissue with abrasive particles, for subsequent safe disposal. A source of sterile abrasive powder (2) is designed to easily load into the device (1 ) and integrate with it via the docking port (15). The source of abrasive powder should dock simply but firmly with the device using any known means but preferably a push, screw or bayonet (push and screw) mechanism and most preferably a push mechanism. Prior to its incorporation into the device the abrasive powder container should be designed to serve as a container which is capable of being hermetically sealed. The abrasive particle container may be constructed from any suitable container material in a size that is consistent with the ease of manipulation of the device when the abrasive container is attached. It should, however, be of at least sufficient capacity for a single treatment of a single patient and will be within the range 10cc to 100cc, preferably 20 to 80cc, most preferably 50cc. In use, the abrasive container is replaced whenever a new patient starts a treatment, to avoid any possibility of cross contamination. The abrasive may be selected from any known abrasive particles, preferably alumina, aluminium trioxide or Corundum powder, most preferably aluminium oxide. The particle size of the abrasive should fall within the range 50 microns to 320 microns, preferably 100 microns to 250 microns, most preferably 150 microns to 220 microns.

The device itself (1 ) may be fabricated from any suitable rigid material such as nylon 66, glass filled nylon, ABS, Acetate preferably a material that is suitable for injection moulding. The various channels (7), (11 ) & (10) may be formed from any suitable flexible polymer tubing, such as Polyethylene, Polypropylene Neoprene or Nylon, capable of carrying a vacuum with a wall thickness of from 0.5mm to 3.0mm especially 1.0mm to 2.0mm and an internal diameter of from 2.0mm to 8.00mm preferably 2.0mm to 6.0mm. Connectors, T junctions and the nozzle (16) where it emerges from the device head (5) may be fabricated in any relatively hard and rigid material such as glass or ceramic. The entire system of channels is constructed in order to be easily replaceable. The nozzle shroud (3) is intended to be replaced after each treatment and is formed from any suitable relatively low surface energy material such as Teflon, Polythene or Propylene, which slides over the skin smoothly. Once the abrasive container is in place within the device, the nozzle shroud is in place, the device is connected to the filter/vacuum generating unit and the vacuum pump is switched on, the apparatus is ready to perform a dermabrasion treatment on a patient. At this stage although the vacuum pump is on and air is being withdrawn from the device via channel (7), because the shroud aperture (4) is open no vacuum is created in the chamber (14) formed by the nozzle shroud (3), and the abrasive powder is undisturbed. The operator aligns the aperture (4) in the nozzle shroud (3) with the area of the patient's skin to be abraded. Once this is done the device is brought into contact with the patient's skin and the shroud aperture is effectively closed. A vacuum builds up within the shroud chamber (14) and air is sucked into the system along channel (11 ) from outlets (12) & (13). However, whilst outlet (12) remains open the abrasive compartment remains undisturbed. The operator can now check that the shroud aperture (4) is directly over the area of skin to be treated and then gently close down outlet (12) forcing the air required to satisfy the vacuum being created in the shroud chamber (14) to be drawn increasingly from outlet (13). The rate of air intake by outlet (12) may be controlled by any known means but preferably by a simple finger operated bleed valve and most preferably by the operator's finger exerting greater or less pressure. Unlike outlet (12), the rate of air intake by outlet (13) is fixed during any treatment with the device but may be varied from treatment to treatment by changing the diameter of the outlet (13) within the range 0.5mm to 2.0mm.

The closing down of outlet (12) in a controlled manner governs the concentration of abrasive particles in the airflow and may be affected in any ergonomically efficient manner from the simple application of finger pressure to the use of levered pads. Once outlet (12) is closed down the only source of air is outlet (13). Air drawn from outlet (13) along channel (11 ) towards the shroud chamber (14) passes the "T" junction with channel (10) leading to the abrasive particle container (2) and in so doing creates a venturi effect which entrains particles of abrasive, from the abrasive container (2), in the air stream which is sucked toward the shroud chamber and projected at the patient's skin beneath the shroud aperture. Once the mixture of air and abrasive particles has impacted with the skin it will be drawn away from the chamber, together with any skin debris, via channel (7) and the flexible vacuum connection.

The exact position of outlet (13) on the outer surface of the device is not critical providing it occurs after the "T" junction of channel (10) with channel (11 ). At all times the operator has complete control of the abrasive aerosol by means of a simple single finger trigger action and the proximity of the device's nozzle shroud to the patients skin surface being treated, enabling her/him to move over the entire skin surface and implement the dermabrasion treatment.

At the end of a session the vacuum pump (9) is switched off and the abrasive container (2) and nozzle shroud (3) are removed from the device and replaced with new sterile items. Because only one flow stream is involved, once an abrasive particle has impacted the patient's skin the unique pathway for the used abrasive/skin debris containing air stream is down stream from the shroud chamber (14) to the filter/collector (8) via channel (7), which never sees an abrasive particle before it has passed through the shroud chamber (14). Just as channel (7) never sees an abrasive particle that has not been through the shroud chamber (14) so the entire airway system up stream from the shroud chamber (i.e. channels (10) and (11 ) never see an abrasive particle after it has been in contact with the skin, thus ensuring that the sterility of the abrasive particles is preserved.

In other embodiments the apparatus may be used on skin to remove scar tissue, acne scars, skin pigmentation marks and tattoos or to abrade other surfaces. The only adjustments that may be required to the apparatus, as described above, to optimise its performance in these embodiments involves adjusting the absolute and relative air flows through the outlets (12) and (13) and in the design of the nozzle shroud (3). As will be clear from figure 3b, in operation when outlet (12) is closed the maximum airflow is dictated by the size of outlet (13) which can be varied from device to device to deliver different airflows. The diameter of inlet may be varied from 0.5mm to 2.0mm. At any fixed outlet (13) size the concentration of abrasive particles entrained in the airflow when it reaches the nozzle (16) will depend on the magnitude of the flow allowed in through the variable outlet (12). Thus by judicious selection of the size of outlet (13) and appropriate control of the airflow coming from outlet (12) all the parameters that define the abrasive efficiency of the device with any particular abrasive particle i.e. total number of particle impacts per second, and the impact speed (energy) of each particle, are under control.

Further adjustment may be needed, particularly when the device is used to microdermabrade sensitive superficial areas of the body. In such embodiments the nozzle shroud (3) may be modified to diffuse the path of the abrasive particles projected from the nozzle (5). Figure 4 shows suitable alternative nozzle shroud designs.

The flow line may be fabricated from any suitable material, for example Polyethylene, Polypropylene, Nylon or Neoprene. Channel junctions, connectors and endings may be fabricated from harder materials such as ceramic and glass.

Aluminium oxide is typically used as the inert abrasive during a microdermabrasion procedure in accordance with the invention.

Cynamins for aluminium oxide include alumina, aluminium trioxide, and corundum powder. The aluminium oxide used in a microdermabrasion procedure may be in the form of aluminium oxide particles. The inert aluminium oxide particles may be irregularly shaped. The aluminium oxide particles may have sharp edges. An electrode process may be used to form aluminium oxide particles having sharp edges. Sharp edged particles may have good abrasive properties when used as an abrasive in a microdermabrasion procedure. Aluminium oxide particles may be sieved so that the aluminium oxide particles are predominantly within a desired size range. Mesh screens may be used to isolate aluminium oxide particles with a desired effective diameter size range. The effective diameter size range for sharp edged aluminium oxide particles useful for microdermabrasion procedures may be from about 50 microns to about 320 microns. Commercially available aluminium oxide particles suitable for use in a microdermabrasion procedure typically include a percentage of fines.

Claims

1. A microdermabrasion device for skin treatment comprising:

• a handset housing a nozzle head and having handle means for manipulating the handset; • a nozzle in the nozzle head for supplying a stream of micro-particulate material to the skin surface in use of the device;

• means for pulling a vacuum in the headspace;

• means for withdrawing debris from the headspace and away from the handset, the nozzle communicating at its downstream end with the headspace and at its upstream end with a flow line having at least two limbs, a first limb communicating in use of the device with the atmosphere, and a second limb communicating in use of the device with a reservoir of micro-particulate material, the first and second limbs being arranged with respect to each other such that the pulling of a vacuum in the headspace when the outlet port is positioned against the skin surface causes an airflow from the atmosphere to the headspace through the first limb of the flow line, and causes material from the reservoir to be drawn into the flow line by means of a venturi effect at the junction of the first and second limbs of the flow line.

2. A microdermabrasion device according to claim 1 wherein the flow line is provided downstream of the second limb with a third limb capable of communicating with the atmosphere.

3. A microdermabrasion device according to claim 1 or claim 2, wherein the second limb is perpendicular to the first limb at the point where first and second limbs join.

4. A microdermabrasion device according to any one of claims 1 to 3 wherein the first limb is provided with a constriction at the point where first and second limbs meet.

5. A microdermabrasion device according to any one of claims 1 to 4 wherein the headspace is defined by a nozzle shroud surrounding the nozzle head and having within it the outlet port for contacting the skin surface.

6. A microdermabrasion device according to any one of claims 1 to 5 wherein the handset is provided with means for mounting a reservoir of micro-particulate material, and for allowing communication of the second limb of the flow line with the contents of the reservoir after such mounting has been made.

7. A microdermabrasion device according to any one of claims 1 to 6 wherein the reservoir is closed except at its point of communication with the flow line.

8. A microdermabrasion device according to any one of claims 1 to 7 comprising: a) a secure docking mechanism for a container of abrasive particles; b) a source of vacuum terminating adjacent to a nozzle; c) a network of channels whereby the source of vacuum creates an airflow which entrains abrasive particles from the container and draws them to the nozzle for projection; and, d) a shroud fitted around the nozzle and the source of vacuum with an aperture, closeable by holding the apparatus against a surface, directly opposite to the nozzle.

9. A microdermabrasion device according to claim 8 wherein the source of vacuum: a) provides an air-stream that can entrain abrasive particles from a docked abrasive container and projects them at the surface being treated through the nozzle outlet; and, b) removes used abrasive particles and any surface debris to a remote filter unit.

10. A microdermabrasion device according to claim 8 or claim 9 wherein: a) the nozzle outlet is attached to a first channel running toward the rear of the apparatus with a first, close to the nozzle, outlet and a second, more distant from the nozzle, outlet to the outer surface of the apparatus and a "T" junction with a second channel running to the abrasive container, situated between the first and second outlets; b) the source of vacuum is channelled through the apparatus, from a connection with a flexible supply line from a vacuum generator, to emerge adjacent to the nozzle inlet; and, c) the nozzle shroud fits over the nozzle and the source of vacuum adjacent to the nozzle and creates an air tight chamber connecting the airflow between the nozzle and the vacuum source when its aperture is closed.

11. A microdermabrasion device according to any one of claims 1 to 10 wherein the device comprises a docking mechanism for accommodating a reservoir with an air tight push fit.