The present invention relates to a ionising device, to be used for enriching air flows with ions, and in particular hot air flows coming from hairdryers, hand-dryers or similar devices.
It is known that creation and admission of electrically charged particles into an air flow enables exploitation of different advantages in terms of air treatment and treatment of the objects that are impinged on by such an air flow.
In particular, application of a given amount of ions to a hot air flow coming from a hairdryer enables better results to be obtained on the hair in terms of drying and "tidiness", mainly due to the fact that the electrostatic charges carried by the hot air flow carry out neutralisation of the charges present on the hair thus reducing the mutual adhesion degree and therefore promoting hair stretching during drying (and ultimately preventing formation of tangles, frizzy hair and so on).
More generally, the beneficial effects of ions in the air consist in sanitation and neutralisation of the polluting agents and smells, as well as in bringing physical welfare to users of apparatuses such as hand-dryers, hairdryers or similar devices.
A hairdryer with an electric heating resistor and an ionising device according to the preamble of claim 1 is disclosed in
While the above described known art has been widely used in different application variants, it however has some drawbacks, above all in terms of density of the charge generated in the hot air flow.
In fact, the different "tip" geometries presently known often are not able to generate a sufficient amount of ions, due both to a too low voltage (that at all events cannot overcome a given threshold, beyond which production of ozone starts) and to the fluid-dynamic conditions in which the tip itself is.
In other words, while generation of charged particles around the "tips" of known type occurs, either these charges are generated in an insufficient number or they are forced to follow a trajectory inside the air flow that leads them to "become exhausted" by impact against obstacles inside the heating instrument; in this manner the generated ions do not succeed in coming out of the heating instrument and actually they do not succeed in exerting any effect on the object that is being submitted to drying.
It is an aim of the present invention to manufacture a ionising device and a support equipped with such a ionising device and a heating resistor equipped with such a ionising device capable of obviating the above mentioned drawbacks.
In particular, the present invention aims at conceiving a ionising device generating a high amount of electrically charged particles and able to disperse them in the most efficient manner from a fluid-dynamic point of view in the hot air flow.
In parallel, the present invention aims at manufacturing a ionising device that can be easily and cheaply mounted on a wide range of supports for heating resistors, and is therefore able to define a heating resistor (for hairdryers, hand-dryers or the like) which is very efficient both in air heating and in air ionisation.
Finally, the present invention relates to creation of a ionising device of proved reliability, simple mounting a low production costs.
The foregoing and further aims are achieved by an electric heating resister with an ionising device in accordance with the present invention having the features recited in the appended claims and hereinafter illustrated in an embodiment thereof given by way of non-limiting example with the aid of the accompanying drawings, in which:
With reference to the drawings, an ionising device is generally denoted at 1 and it substantially comprises at least one dispersion tip 1 which is adapted to generate and disperse a predetermined amount of electrically charged particles in a flow (which flow in turn will typically be a hot air flow emitted by a hairdryer and the like, or more generally an air flow that is submitted to heating through a heating resistor); then suitable electric supply means 3 is present which connects the dispersion tip 12 to an electric energy source.
A potential reference body 4 is interposed between the dispersion tip 2 and the electric supply means 3, so as to amplify the electrostatic effect of ionic generation (or more generally the electrostatic effects linked to the electrostatic-potential difference between the dispersion tip 2 and the electric energy source).
Unlike known ionising devices that practically do not oppose any "electric mass" to the tip, the present invention provides an additional circuit element interacting with the dispersion tip so as to increase efficiency and homogeneity in producing electric charges in the air flow.
Depending on the amount of electric charges that are wished to be generated, the presence of several dispersion tips 2 can be provided, as shown in the drawings for example; in these cases, each dispersion tip will have its respective extension axis, and preferably these extension axes will be mutually parallel.
These dispersion tips 2 are connected to the potential reference body 4.
Conveniently, the dispersion tip 2 is made of an electrically conductive material and has a tapering course defining a main extension axis 2a; at the same time, the potential reference body 4 is rigidly connected to the dispersion tip 2 and is therefore made of an electrically conductive material that is coincident with the material of the dispersion tip 2.
In other words, the dispersion tip 2 and the potential reference body 4 constitute a single piece which is then connected to the electric supply means 3.
With reference to the drawings, it is possible to see that the potential reference body 4 can be made according to different geometries, depending on current requirements but it must be always sized and positioned such as to exert the above described amplification effect.
In one of the possible embodiments herein illustrated, the potential reference body is a laminar body extending in a lying plane 4a substantially parallel to the main extension axis 2a and preferably containing the main extension axis 2a.
In addition, in another embodiment herein shown the potential reference body 4 is a laminar body extending in a lying plane 4a substantially transverse (and preferably perpendicular) to the main extension axis 2a.
The geometry of the potential reference body 4 can be of any type, provided it is a laminar body and has a sufficient surface for exerting the amplification effect of the electrostatic-charge generation underlying the present invention; conveniently, selection of the geometric figure to be given to the potential reference body also takes place based on the perturbing effect that is wished to be given to the hot air flow grazing said body under operating conditions.
With reference to the accompanying drawings, the potential reference body 4 is shaped like a polygon (that depending on current requirements can be a trapezium, a parallelogram or a rectangle and so on); in particular, at least one "base" of this polygon (the minor base of said trapezium, for example) is positioned adjacent to the dispersion tip 2, so as to support it; it is also to be noted that the dispersion tip 2 itself is connected to the potential reference body without a break.
In order to ensure the necessary structural and functional coherence, a support 5 is also present which comprises at least one thin sheet (that is generally made of a heat-resistant and/or electrically insulating material and, depending on current requirements, can also be coated with mica or another anti-static material); support 5 defines an orientation axis 5a and conveniently the dispersion tip 2 is mounted on this support 5 in a staggered configuration relative to the support 5 itself.
Positioning of the dispersion tip 2 is determined in such a manner that the fluid-dynamics of the air flow grazing the support can be exploited; in fact, staggering is such selected that the trajectories of the ions generated in the vicinity are capable of bringing the ions themselves to the outside of the heating device, and at the same time staggering is such selected that the dispersion tip 2 is not placed to an excessively perturbing position for the flow.
Should support 5 include two or more thin sheets intersecting at a central axis (which axis can be defined as a mid-line axis which is oriented along and is coincident with the orientation axis 5a), the dispersion tip 2 would be conveniently mounted in a staggered configuration relative to at least two contiguous faces of at least two thin sheets of support 5.
Consistently with the above described positioning criterion, the dispersion tip 2 (or dispersion tips, when more than one of them are present) has a minimum transverse staggering value relative to at least one thin sheet of support 5; this minimum staggering value is at least proportional to a speed profile of a flow on support 5 and/or to a distance from one end of support 5 placed downstream of the flow; according to particularly appreciable embodiments of the present invention, said minimum staggering value is most preferably included between 3 and 12 mm.
In order to find an optimal compromise between efficiency of dispersion of the electric charges and perturbation of the hot air flow, the dispersion tip 2 and/or the potential reference body 4 of the present device can have different configurations; for instance, the main extension axis 2a of the dispersion tip 2 can be parallel to the orientation axis 5a of support 5, while the lying plane 4a of the potential reference body 4 can be parallel or normal to the orientation axis 5a of support 5.
Still with reference to the accompanying drawings, in
Depending on current requirements, the alternative embodiment shown in
It is also an aim of the present invention to provide an electric heating resistor, preferably to be used for heating hot air flows (and therefore suitable for installation in hairdryers, hand-dryers or similar machines); this heating resistor comprises:
Still with reference to the accompanying drawings, it is possible to see that the ionising device can be only one, or a double ionising device can be present which is disposed either on opposite faces of the same thin sheet, or on opposite sides of the same face of a given thin sheet or also on adjacent faces of different thin sheets, depending on current requirements.
Mechanical connection between the ionising device is conveniently ensured through suitable connecting means 6 which depending on requirements can be of any type; for instance, with reference to the drawings this connecting means 6 consists of a rivet means passing through a suitable hole in a thin sheet constituting the support 5 and adapted to electrically connect the potential reference body 4 and/or the dispersion tip 2 to the electric supply means 3.
It is to be noted that the described rivet means enables very quick assembly of the whole heating resistor, and simultaneously perform two functions (structural coherence and electric continuity).
The invention enables achievement of important advantages.
First of all, the particular construction architecture of the ionising device, on the one hand, allows an efficient exploitation of the electric potential difference thereby generating much more electric charges (dispersed in the air) as compared with the structures of known type and, on the other hand, also allows these electric charges to be discharged in the hot air flow so that they can reach the hot air outlet in a great amount (i.e. without impacting against the filaments of the heating resistor or the walls of the support, or in any case against other inner surfaces of the heating instrument).
Secondly, the present invention can be easily configured both as to its position along the extension axis of the support/resistor, and as to the height for insertion into the flow, so that it is adaptable to a great variety of geometries and/or extensions of the heating resistors and/or the supports.
In addition, advantageously, the presence of ionising devices in a single heating-resistor support can be doubled or multiplied; in this manner there is an exponential increase in the ionic density of the hot air emitted by the heating instrument.
Finally, the present invention enables manufacture of the supports for heating resistors and manufacture of the heating resistors themselves to take place at low production costs, which will involve low sale prices.
This list of references cited by the applicant is for the reader's convenience only. It does not form part of the European patent document. Even though great care has been taken in compiling the references, errors or omissions cannot be excluded and the EPO disclaims all liability in this regard.