Patent Grant
8814059
The present invention relates to an atomizing device, comprising an atomizing body with at least one inlet for receiving a fluid under increased pressure, and with at least one set of outflow ports for allowing the fluid to escape on a delivery side with forming of a vapour, wherein imaginary central axes of the outflow ports directed in a flow direction enclose a mutual angle in order to intersect each other at an intersection. The invention also relates to a method for manufacturing an atomizing device.
An atomizing device of the type described in the preamble is usually applied to form a vapour or mist of finely distributed droplets, in some cases with a relatively narrow size distribution, from a liquid. In addition, such an atomizing device can be applied to form a dispersion or colloidal solution of a fluid in a further fluid.
An atomizing device of the type described in the preamble is known from European patent EP 1.644.129. The known device comprises an atomizing body which is formed from two substantially plate-like substrates, respectively of silicon and glass, which are firmly connected to each other. On a first side the atomizing body comprises an inlet for a liquid for vaporizing and a set of outflow ports on an opposite delivery side. Situated therebetween is a liquid chamber into which a liquid for vaporizing is admitted at an operating pressure in the order of 50-300 bar.
The liquid can escape from the liquid chamber via a set of outflow ports on the delivery side, wherein these outflow ports are oriented at an angle relative to each other. A set of liquid jets making said angle relative to each other and meeting at an intersection outside the body are thus formed on the delivery side. As a result of the collision of the two liquid jets they divide into small droplets at and close to the intersection and thus form a vapour. This process is also referred to as the “impinging jet” principle and has for instance been described by Savart (1833) and Taylor (1959).
Such a device is suitable for many applications for forming a colloidal vapour in air from a fluid, varying from more or less high-quality inhalers for pharmaceutical products, which must provide a very accurate spray pattern with a droplet size within narrow limits in order to optimally enhance absorption of the pharmaceutical product by the body via the airways, to nozzles for spray cans and pumps, in which droplet size is usually greater and in particular less critical. Terms such as vaporizing, spraying, nebulizing and similar terms are otherwise deemed equivalent within the scope of the present patent application and, accordingly, terms such as spray, vapour, aerosol and mist are deemed mutually interchangeable.
In the known device the outflow ports open onto a free main surface of the vaporizing body, which forms an outer boundary of the atomizing body and extends between an upper side and an lower side thereof. Unavoidable tolerances in a manufacturing process of the atomizing body in which this main surface is formed will hereby be of unmistakable influence on a channel length, and thereby on an outflow resistance of the outflow ports. This is the case particularly because the known atomizing body, among other places on the vulnerable delivery side, is released from a greater whole by cleaving, cutting or sawing during manufacture. Not only can this bring about irregularities in the edge of the body, and thereby of the outflow ports, it can also cause contamination of the passage system in the atomizing body due to the entry of substrate particles and applied additives, which may result in blockage and loss. This sets high requirements in respect of the sawing or similar separating process, as indicated in EP 1.644.129. Furthermore, as a result of unavoidable dimensional tolerances the distance from the intersection to the outflow ports may thus possibly vary from atomizing body to atomizing body. This can result particularly in an undesirable asymmetry of the outflow ports. These parameters influence the vaporizing pattern of the device, which has an adverse effect on the reproducibility of the device as a whole and, in the most extreme case, can also result in loss.
The present invention has for its object, among others, to provide an atomizing device of the type stated in the preamble in which such fluctuations are avoided, or at least the influence thereof on operation of the device is significantly reduced, and which moreover allows of considerably simpler precision manufacture. In further aspects the invention has for its object to provide an atomizing device with a fitting envelope and method for manufacture thereof.
In order to achieve the first stated object, an atomizing device of the type described in the preamble has the feature according to a first aspect of the invention that the atomizing body comprises a vaporizing space which is open on the delivery side and into which the at least one set of outflow ports opens, wherein the intersection of the central axes of the outflow ports is located outside the vaporizing space, that the atomizing body comprises at least a first substrate with a substantially flat main surface and a second substrate with a substantially flat main surface, which are mutually connected on their main surfaces, and that at least one of the at least one inlet, the set of outflow ports and the vaporizing space is formed at least partially on at least one of the two said main surfaces.
The edges of the thus present vaporizing space lie outside the reach of the outflow ports. A length, orientation and morphology of the outflow ports is therefore not influenced by variations on or of these edges. The intersection of the two liquid jets is also situated wholly outside the atomizing body and beyond the influence of possible variations in the edges of the vaporizing space. The invention is based here on the insight, among others, that an outflowing liquid jet will form a boundary layer on a boundary surface with a roof and bottom of the vaporizing space, where a speed of the outflowing liquid jet will be low to zero relative to a centre of the liquid jet, whereby no or hardly any changes in speed or variations in flow resistance will occur as a result of possible variations in a distance over which the vaporizing space protrudes relative to the outflow ports.
By making use of an assembly of two substrates combined on their main surface for the atomizing body, the whole structure can be arranged superficially with a high degree of precision and freedom of form in order to thus create a device with a precisely determined, readily reproducible vapour pattern.
Substrate residues, which are released during a sawing process when the atomizing body is separated from a larger whole, are moreover less likely to penetrate the passage system of the atomizing body because the outflow ports are located at a distance from the saw cut. It is thus not necessary to resort to time-consuming and cost-increasing special sawing methods such as in the prior art device, and it is possible if desired to suffice with standard separating techniques such as sawing, (laser) cutting and cleaving. In the design of the outflow ports it is moreover not necessary to take into account a possible fracture line tolerance or similar fluctuations in the manufacturing process, since in the atomizing device according to the invention the side surface onto which the outflow ports open does not bound the atomizing body as such.
A particular embodiment of the atomizing device is characterized here according to the invention in that said substrates form a roof and a bottom of the vaporizing space which extend over at least a first distance beyond the set of outflow ports, and that the intersection of the imaginary central axes of the outflow ports lies at a second distance from the set of outflow ports, this second distance being greater than the first distance. A further embodiment is more particularly characterized in that the second distance is at least about 100 micrometers greater than the first distance. The roof and the bottom thus protrude beyond the outflow ports and receive the vaporizing space therebetween, although the intersection is sufficiently far removed for the break-up of the fluid into small droplets to encounter no, or hardly any, obstruction from the presence of the vaporizing space.
In order to limit an outflow resistance of the fluid, a further preferred embodiment of the atomizing device according to the invention has the feature that a length of the outflow ports is smaller than a transverse dimension thereof, in particular between one and ten times smaller. By thus keeping the outflow ports relatively short in comparison to their diameter an outflow resistance thereof is at least substantially minimal, and thereby a pressure drop over the outflow port during operation, this enhancing the vapour pattern and allowing a lower operating pressure. A particular embodiment of the atomizing device according to the invention has the feature in this respect that the outflow ports have a transverse dimension greater than about 20 micrometers and a length of less than 20 micrometers.
A further preferred embodiment of the atomizing device according to the invention has the feature that a liquid chamber is formed at least partially on at least one of the two said main surfaces, which liquid chamber is in open communication with the at least one inlet and with the at least one set of outflow ports, and that the liquid chamber extends at least substantially as far as an outflow opening of the outflow ports. A length of the outflow ports is here reduced substantially to a minimum in practical manner so that a pressure drop over the port is minimal. Such a structure can be realized with a high degree of precision making use of for instance lithographic techniques as used in semiconductor technology or with micro-electro-mechanical systems (MEMS), micro-nano technology and other high-precision techniques such as LiGA (Lithographie-Galvanoformung-Abformung), precision injection moulding, micro-moulding, electroforming and stereolithography. Particular use can be made here of printing techniques in which a precision stamp acts on a hot, curable substrate, in particular of a thermoplastic plastic.
Such a stamp can for instance be manufactured by imaging and etching the positive surface structure thereof in a (silicon) substrate with a high degree of precision and by using the semiconductor substrate as a casting mould for a body of metal, in particular nickel, to be cast or deposited therein. This metal body then forms the precision stamp to be used, which acts on a hot plastic substrate, for instance of polycarbonate, for the purpose of arranging the described structure of the atomizing body therein, which then cures. Such a precision stamp can otherwise also be realized in numerous other ways within the scope of the invention. If the structure of a series of vaporizing bodies is here pressed simultaneously in a substrate and the individual vaporizing bodies are only separated later, the invention here also provides the advantage that such as separating step will not influence the integrity and operation of the outflow ports, and moreover leaves space for simple, standard separation.
Such techniques also clear the way for more complex outflow port structures which further optimize the operation of the device. A further preferred embodiment of the atomizing device according to the invention has in this respect the feature that the outflow ports are provided in respective wall parts of the atomizing body, which wall parts are oriented at an angle relative to each other and extend at least substantially transversely of a central axis of the outflow port provided therein. The relative orientations and dimensions of both the wall parts and outflow ports can be determined within highly precise limits, whereby it is possible to aspire to and also actually achieve an optimal vaporization. A further particular embodiment of the atomizing device has the feature here that the imaginary central axes of the outflow ports enclose a mutual angle of between 30 and 120 degrees.
A further preferred embodiment of the atomizing device according to the invention is characterized in that the wall parts comprise outflow openings of the outflow ports, wherein the outflow openings are oriented at least substantially transversely relative to the respective imaginary central axes of the outflow ports. A disruptive influence of the outflow port on the spray pattern can thus be reduced, particularly in the case of a relatively short channel length in an outflow port. This has also been found in practice to be a significant advantage relative to the known atomizing device, wherein the outflow openings lie at what is clearly a non-right angle relative to the flow direction through the outflow ports.
Use is generally made in the stated techniques of a starting substrate on which different processes are performed. A further particular embodiment of the atomizing device according to the invention has the feature that the outflow ports are formed monolithically with at least one of the roof and the bottom of the atomizing body. At least one of the two walls as well as the port structure and the inlet are here formed integrally. Further assembly steps and mutual alignments, which could otherwise detract from ease of manufacture and the accuracy of the device, are thus avoided. Using stereolithography in a polymer resin or modern laser-assisted manufacturing techniques, wherein for instance glass or a plastic is illuminated locally and only the illuminated parts are etched away, the whole atomizing body can, if desired, be formed in wholly monolithic manner, i.e. integrally.
A further particular embodiment of the atomizing device has the feature here that the atomizing body comprises at least one substantially plate-like substrate of a material taken from a group comprising plastics, metals, semiconductor materials, in particular silicon, ceramic materials and glass, and that the at least one inlet and the outflow ports are arranged on a main surface of at least one of the at least one substantially plate-like substrate. Said materials are at least highly compatible with the above stated high-precision and semiconductor techniques. The desired internal structure of the atomizing body can thus be realized on the surface, for which purpose it is possible to resort to surface techniques proven in semiconductor technology and in many high-precision processing methods. The surface can then be covered with a further substrate and hermetically connected thereto.
In order to prevent blocking of the outflow ports, a further embodiment of the atomizing device according to the invention has the feature that the inlet is provided with an inlet filter. Such an inlet filter comprises for instance a grid and has passage openings with a transverse dimension of typically more than 20 micrometers. Such a grid can advantageously be formed monolithically together with the inlet and outflow ports in said at least one substrate.
In order to form a finely distributed vapour from a liquid or other fluid, the fluid must be carried through the outflow ports under increased pressure. For this purpose a further particular embodiment of the atomizing device according to the invention has the feature that pressure means are provided for the purpose of presenting the fluid to the at least one inlet at an operating pressure of 1 to 20 bar, at least below about 50 bar. In the device according to the invention such a relatively limited pressure is found to be sufficient for a satisfactory aerosol pattern without having to make use of volatile substances such as propellants or alcohol in order to improve the aerosol pattern. The device according to the invention has moreover been found to be particularly suitable for forming a non-inhalable vapour such as is particularly desirable for vaporizing for instance personal hygiene products such as deodorant, skin sprays and hair spray, and domestic (cleaning) products. In a vapour produced by this embodiment an average droplet size lies manifestly above a critical limit of about 10 micrometers, whereby an inhalable fraction of the thus formed vapour is exceptionally small or even absent. This makes a significant contribution toward the safety and the enjoyment of use for the end user.
In addition to a monolithic structure realized with semiconductor precision, the invention is also suitable for low-precision implementation, whereby a considerable cost price reduction can be achieved and less stringent manufacturing conditions are required. A second aspect of the invention therefore has for its object, among others, to provide an atomizing device which, while retaining at least some of the above stated advantages, can be realized at relatively low cost price and with relatively simple manufacturing techniques.
In order to achieve this object, an atomizing device comprising an atomizing body with at least one inlet for receiving a fluid under increased pressure and with at least one set of outflow ports to allow the fluid to escape on a delivery side with forming of a vapour, wherein imaginary central axes of the outflow ports directed in a flow direction enclose a mutual angle in order to intersect each other at an intersection, wherein the atomizing body comprises a vaporizing space which is open on the delivery side and into which the at least one set of outflow ports opens, which vaporizing space is bounded on opposite sides transversely of a delivery side and wherein the intersection of the central axes of the outflow ports is located outside the vaporizing space, has the feature according to the invention that the atomizing body comprises on the delivery side an insert which, at least in a plane formed by the central axes, bounds a cup-like recess which forms the vaporizing space, wherein the set of outflow ports is arranged in opposite wall parts of said recess. Such an insert can be manufactured individually as a separate component and then assembled with the other part of the atomizing body. The requirements set herefor are not per se stringent. A particular embodiment is characterized in this respect in that the insert comprises a metal plate part, and more particularly that the recess is punched into the plate part. Such a plate part and punching technique are relatively low-precision and can be realized in a relatively simple production environment.
In a further embodiment the atomizing device according to the invention is characterized here in that the wall parts extend from a concave surface, in particular a cylindrical surface or a spherical surface. Such a spherical form has the advantage here relative to a cylindrical form that the outflow ports are always correctly aligned relative to each other so that both liquid jets will always strike each other at the intersection. Although the final vapour pattern may here become slightly askew, this will not be perceptible, or hardly so, for many applications and so not pose a problem. With other forms, such as an angular wall or cylinder wall, the mutual alignment of the outflow ports is more precise in order to ensure that the liquid jets actually meet each other.
According to further aspect, the invention has for its object, among others, to provide an atomizing device with an atomizing body which is embedded in a fitting envelope, and a method for realizing this.
In order to achieve this object an atomizing device comprising an atomizing body with at least one inlet for receiving a fluid under increased pressure and at least one outflow port for allowing the fluid to escape on a delivery side with forming of droplets formed at least partially therefrom, wherein the atomizing body is received in an envelope comprising at least one envelope part with at least a part of a seating for the atomizing body, has the feature according to a further aspect of the invention that the atomizing body is able and adapted to capture a supplied radiation, thus forming heat, that the atomizing body in the seating is accessible to the supplied radiation, and that provided on a boundary surface between the envelope and the atomizing body is a boundary layer which has entered into heat-exchanging contact with the atomizing body and under the influence thereof has brought about a practically hermetic adhesion between the atomizing body and the envelope.
An adhesion of the envelope to the atomizing body, and thereby a mutual fixation and sealing, is thus achieved by providing said radiation after the atomizing body and the envelope have been joined together. A completely contact-free heating is thus possible, which takes place substantially locally and thereby leaves a mutual, initial positioning of the two parts intact and requires relatively little energy. The envelope adhered to the atomizing body herein moreover ensures a seamless seal with the atomizing body so that the atomizing body is fixed in the envelope in leakage-free manner and the device is ready for possible further finishing. As well as being used for non-inhalable sprays, such an envelope can also be applied for inhalable sprays and is in principle suitable for any type of atomizing body, varying from the above described type on the basis of colliding liquid jets to vaporizing bodies in which a fine vapour is formed from a liquid by so-called Rayleigh break-up or by atomization, as well as to emulsifiers with which liquids can be introduced colloidally into other liquids in order to thus realize various (co-)emulsions.
In a preferred embodiment the envelope comprises at least on a delivery side of the atomizing body a spacer part which is able and adapted, under all conceivable conditions, to maintain a distance from the seating in which the atomizing body is received. If a number of thus enveloped vaporizing bodies are stored together in a storage box or in other manner, i.e. not in a single packaging, an atomizing body is sufficiently recessed and protected in an envelope to prevent the vulnerable outflow ports of the atomizing body coming into contact with a part of another atomizing device during storage or transport.
A particular embodiment of the atomizing device according to the invention is characterized in that the at least one envelope part comprises a thermoplastic material and that the boundary layer comprises a top layer of the envelope part which is melted around the atomizing body. A further particular embodiment of the atomizing device according to the invention has the feature here that the envelope comprises at least two mutually connected envelope parts which bound the seating at the position of the atomizing body and are fused together, thus enclosing the atomizing body. Here the same advantages not only apply between the atomizing body and the envelope, but also between the envelope parts relative to each other. Making the envelope parts from the same at least compatible material moreover enhances a durable and seamless mutual fusing. For this purpose a further particular embodiment of the atomizing device according to the invention has the feature that the envelope parts comprise at least in the boundary layer a thermoplastic plastic, particularly one from a group of polyolefins and polyamides.
Such a fusing of the atomizing body can cause lateral shrinkage and stress around the seating. In order to prevent the envelope being pulled away from the atomizing body as a result thereof, a further preferred embodiment of the atomizing device according to the invention has the feature that the envelope part comprises on the main surface an edge part bounding the seating, and that the edge part is separated by a groove from a further-removed part of the envelope part. A possible tensile force which could otherwise be exerted on the adhesion of the atomizing body in the seating by the further-removed part of the envelope part is thus effectively interrupted by the groove. A further preferred embodiment of the atomizing device has the feature here according to the invention that the edge part at least substantially wholly surrounds the seating. A further embodiment more particularly has the feature that the groove has a depth which is at least substantially equal to a depth of the seating. An effective stress interruption is thus realized on all sides over at least substantially a full depth of the seating. A groove depth of roughly two thirds of the depth of the seating is here deemed to be sufficient.
Instead of via at least a boundary layer of a thermoplastic plastic, the adhesion between the envelope and the atomizing body can also be realized in other thermally activated manner. Use is made hereof in a further particular embodiment of the atomizing device according to the invention, which is characterized in that the boundary layer comprises a thermosetting glue layer which is applied between the envelope part and the atomizing body and which, in hardened state, connects the envelope part and the atomizing body. For the hardened boundary layer use can for instance be made of a thermally setting glue, such as for instance an epoxy glue, which has been thermally activated.
The intended absorption of radiation by the atomizing body can be of different nature in a physical sense. Use can thus be made of different forms of electromagnetic capture, wherein use is made of an electrical (semi)conductor material for the atomizing body. The chosen material and the nature and frequency of the radiation can be adjusted to each other relatively accurately in a manner such that electromagnetic absorption occurs in the atomizing body, wherein particles in the material are moved more rapidly and so rise in temperature. The frequency of the radiation must here be adjusted within relatively narrow limits to the particles for displacing. Such a mechanism occurs for instance in relatively high-frequency microwave radiation, and dipole materials which can be moved more rapidly thereby.
Use can also be made of the generation of induction currents in the atomizing body in order to increase the temperature thereof. It has been found in practice that particularly high local temperature increases can hereby be achieved in a short time which are sufficient for fusing of some envelope materials. With a view hereto, a further preferred embodiment of the atomizing device according to the invention has the feature that the atomizing body comprises an electrically conductive material, in particular one from a group comprising metals and semiconductor materials. The conductivity of these materials allows a supplied electromagnetic alternating field to be captured therein and to generate induction currents. Other than in electromagnetic resonance, the chosen frequency of the supplied radiation is less critical here, and can be significantly lower. In a further preferred embodiment the atomizing body herein has the feature that the atomizing body is formed at least partially from silicon. In addition to the electrical and thermal conductivity, this material provides many advantages from a production engineering viewpoint because modern semiconductor technology and micro to nanomechanics are widely adapted to this material.
In addition to such an electromagnetic capture, use can also be made of optical absorption within the scope of the invention. For this purpose a particular embodiment of the atomizing device according to the invention has the feature that the atomizing body is optically absorbent and that up to the atomizing body the envelope comprises at least a window which is substantially transparent to the supplied radiation. This embodiment is suitable for local heating of the atomizing body under the influence of light which is supplied with a sufficient power, for instance making use of a laser. Because the atomizing body here does not have to be electrically conductive per se, a wide range of optically absorbent materials can be applied for this purpose, including isolators.
Particularly for applications in inhaler devices, wherein on the delivery side of the atomizing body a transverse airflow is supplied to which the formed vapour is relinquished, a further preferred embodiment of the atomizing device according to the invention has the feature that the atomizing body is at least substantially plate-like and is bounded by at least substantially flat main surfaces onto which the at least one inlet and the at least one outflow port open, and that on the delivery side a main surface of the atomizing body at least substantially coincides with the main surface of the envelope part. The atomizing body thus lies substantially flush with the main surface of the envelope part so that the atomizing body disrupts a transverse airflow along the delivery side as little as possible.
A method for manufacturing an atomizing device, wherein an atomizing body is placed in a seating provided for this purpose in an envelope part and fixed therein, has the feature according to the invention that the atomizing body is placed in the seating in direct heat-exchanging contact with a boundary layer, that the atomizing body is subjected to radiation of a nature and frequency which is captured by the atomizing body with generation of heat, and that the atomizing body is fixed in the seating by causing the boundary layer to enter into a durable adhesion with at least the atomizing body under the influence of the heat developed in the atomizing body. A wholly contact-free and seamless fixation of the atomizing body in an envelope is thus possible, so that a hermetically sealed whole is finally obtained. This provides considerable advantages relative to conventional methods of manufacture wherein the atomizing body and the envelope must be glued via for instance a contact glue.
A particular embodiment of the method according to the invention herein has the feature that a first and a second envelope part envelop the seating on a mutual contact surface and are joined together to form a releasable assembly while enclosing the atomizing body, that use is made for the envelope parts of envelope parts which comprise a thermoplastic plastic on at least the contact surface, and that the assembly is subjected to a treatment with said radiation in order to fuse together the whole at least at the position of the atomizing body under the influence of the heat developed in the atomizing body. The atomizing body is here first enclosed releasably between the two envelope parts, wherein a certain degree of freedom is still present for a mutual repositioning and alignment. Once correctly assembled, the whole is then subjected to a contact-free heating step which avoids disruption of the mutual positioning of the components.
A further embodiment of the method according to the invention has the feature that the atomizing body is placed in the seating via a thermally setting boundary layer and that the boundary layer is set under the influence of the heat developed in the atomizing body. The envelope therefore need have no thermoplastic properties per se, and use can be made of a commercially available, thermally setting glue, for instance on epoxy basis, which is further activated in contact-free manner under the influence of heat relinquished by the atomizing body.
In a further particular embodiment the method according to the invention is herein characterized in that use is made for the atomizing body of an electrically conductive material, in particular a metal or semiconductor material, and that the assembly is subjected to electromagnetic radiation, in particular microwaves, of a nature and frequency which at least substantially passes through the envelope part but which is captured by the atomizing body with generation of heat. The at least one envelope part can here be integrally permeable to the supplied radiation, i.e. be fully transparent or at least translucent to the supplied radiation, or locally comprise a window which exposes the atomizing body to the supplied radiation. The envelope part on the one hand thus allows passage of the supplied radiation but softens and melts under the influence of the heat generated in the atomizing body on a boundary surface therewith.
A further particular embodiment of the method according to the invention has the feature that use is made for the atomizing body of an optically absorbent material and that a high-energy light beam is directed at the atomizing body with a light source, in particular a laser. Here also the at least one envelope part can optionally be integrally transparent to the supplied laser radiation or locally comprise a window in which the atomizing body is visible. The heat which is released by the laser radiation being absorbed by the atomizing body also provides in this embodiment a seamless fusing of the atomizing body at the boundary surface with the envelope.
The invention also relates to an atomizing body as can be applied in the above described atomizing device according to the invention, and will now be further described on the basis of a number of exemplary embodiments and an accompanying drawing. In the drawing:
The figures are purely schematic and not drawn to scale. Some dimensions in particular are exaggerated to greater or lesser extent for the sake of clarity. Corresponding parts are designated in the figures with the same reference numeral.
A bottom part 10 of the atomizing body is formed wholly monolithically by etching from a silicon substrate and comprises, in addition to a bottom 11, a structure of walls 12-14 which together bound a liquid cavity 15. On a first inlet side liquid cavity 15 is in open communication with an inlet 16 which, if desired, is provided with a simultaneously formed inlet filter in the form of a grid structure etched out of the substrate. During operation a fluid for vaporizing is admitted via inlet 16 into the liquid cavity under increased pressure in the order of 1-20 bar, at least below 50 bar. The atomizing device comprises for this purpose pressure means and feed means (not further shown) outside the atomizing body.
On a delivery side bottom part 10 comprises a set of outflow ports 18 into which liquid cavity 15 debouches in order to allow a fluid in the form of two jets 31,32 directed toward each other to escape from a set of outflow openings 19, see also
Owing to the photolithographic masking techniques and etching processes taken from semiconductor technology the bottom structure shown in
If a liquid or other fluid is admitted into the atomizing body under increased pressure, the liquid will escape at the set of outflow ports 18 with forming of two liquid jets 31,32 which meet each other in or close to intersection S. As a result the colliding liquid jets 31,32 break up into fine droplets which are colloidally suspended in the ambient air to form a fine vapour 33. It has been shown that a size distribution of the thus formed vapour droplets lies within relatively accurate limits around 10 to 100 micrometers, whereby the device according to the invention is particularly suitable for non-inhalable sprays, both in propellant-containing spray cans and in propellant-free pumping cans.
Apart from the inlet pressure and the nature of the liquid, the vapour pattern depends mainly on the port structure 18,19 and the surface morphology of wall structure 13,14 of the atomizing body on the delivery side. Because these structures are determined in wholly photolithographic manner and with a high degree of precision, the device can be manufactured with an extremely high reproducibility, wherein the vapour pattern will not vary from device to device, or hardly so. Contributing to this is the fact that the vaporization in the device according to the invention takes place between a protective structure of projecting parts of roof 21 and bottom 11, which protrude a distance d3 beyond the side wall structure 13,14. This is shown in detail in
Owing to the invention the atomizing body comprises a vaporizing space 17 for receiving the liquid jets therein which is located outside outflow ports 18 and which is bounded on opposite sides by the roof and the bottom of the atomizing body, but which is fully open on the delivery side in order to allow escape of the set of liquid jets directed toward each other. The intersection S of the escaping liquid jets lies here at a greater distance from outflow ports 18 than the distance over which the roof and the bottom extend beyond outflow ports 18 and is thus outside the vaporizing space 17 bounded on either side by the roof and the bottom. A separating operation, wherein the atomizing body is separated from a larger whole along an outer edge of the roof and the bottom, hereby has hardly any influence on the operation, and in particular the vaporizing properties, of the atomizing body, whereby it can be manufactured on industrial scale with extremely high reproducibility and output.
Both bottom 11 and roof 21 of the atomizing body extend a distance d1 beyond outflow ports 18, while intersection S of colliding liquid jets 31,32 is located a distance d2 from the same ports 18. In this example the first distance d1 amounts to about 30 micrometers and the intersection lies about 60 micrometers from ports 18. A possible slight variation in the length d1 has been found in practice not to disrupt the vapour pattern of the device at all. Possible edge finishings or for instance variations in a cutting, sawing or cleaving process for separating the atomizing body from a larger whole here do not therefore affect the vapour pattern of the final device.
Because the structure of outflow ports 18 can thus be determined in wholly photolithographic, micromechanical or other manner with a very high degree of precision and particularly because a break line running therethrough does not have to be taken into account, ports 18 can be provided with a relatively short channel length. In the present example this is achieved in that liquid chamber 15 extends to a distance λ, of only about 5 micrometers from outflow openings 19 of outflow ports 18, see
An atomizing body of a second embodiment of an atomizing device according to the invention is shown in
At the position of their mutual intersection the jets entering each other break up into a fine vapour. This intersection here also lies outside the boundaries of a roof 21 and a bottom 11 formed by protruding parts of the two body parts 10,20, while outflow ports 18 lie within this boundary. Injection moulding techniques offer a great freedom of form, this being manifest here in, among other parts, the round outflow openings 19 and cylindrical outflow ports 18 used here. Although the accuracy of the thus obtained structure will be less than the extremely high precision of the semiconductor techniques and microsystem techniques applied for the first example, the accuracy has nevertheless been found to be amply sufficient for the purpose of thus manufacturing a suitable atomizing device in serial production at a relatively low cost price.
A third exemplary embodiment of an atomizing body of an atomizing device according to the first aspect of the invention is shown in
For the forming of an atomizing body from plastic use can optionally also be made of modern modelling techniques such as stereolithography and rapid prototyping, wherein, using a microprocessor-controlled laser, the atomizing body can be directly written three-dimensionally in optionally integral form in a (resin) liquid adapted thereto or be imaged therein using a set of masks, whereby the liquid cures locally in order to form the body. It is possible here to opt to form the bottom part separately from the roof part, although the whole atomizing body can also be formed as a monolithic whole from the resin in one operation. An example hereof is shown in
The figures here show the atomizing body from opposite perspective directions. The atomizing body thus comprises one monolithic whole 10 in which the desired vaporizing structure is imaged and formed using the above described techniques.
In addition to being embodied as a chip-like body which can be placed in a suitable envelope for handling purposes, the atomizing body can also be embodied as a larger whole which can for instance already be applied per se in a nebulizing device. A fifth exemplary embodiment of the atomizing device according to the invention gives an example hereof and is shown in
Both components 10,20 are manufactured with high precision by moulding (injection moulding) from a suitable plastic such as polycarbonate or an amorphous plastic, such as particularly a transparent, amorphous copolymer of both cyclical and linear olefins, commercially available under the name TOPAS COC. With this combination of material and technique micro-structured channels 16,18 with a width and depth in the order of 20 to 50 micrometers are feasible. Relatively high-quality nebulizers, which are for instance suitable for perfume and deodorant sprays, can thus be realized at relatively low cost price.
Arranged here with high precision on a main surface 21 of second part 20 directed toward base part 11 is a surface structure, which is shown in more detail in a bottom view of
The two parts 10,20 are hermetically connected to each other by means of thermo-bonding and then form a non-breakable closed whole as shown in
An atomizing body of a sixth embodiment of an atomizing device according to the invention is shown respectively in perspective view and in cross-section in
In this example wall part 10 comprises an insert, although it can optionally also be formed monolithically with adjacent part 20 of the atomizing body. Just as the other part 20 of the atomizing body, the insert can be manufactured from various materials, including particularly metals in addition to semiconductor materials, glass and plastic. In this example use is made of metal and the wall part comprises a plate-like metal part brought into the shown form with semi-cylindrical vaporizing space 17 via punching. Outflow ports 18 typically have a diameter of 20-50 micrometers and can be arranged in standing part 10 by means of electroforming or etching.
In this example wall part 10 also comprises an insert, although it can, if desired, also be formed monolithically with adjacent part 20 of the atomizing body. Just as the other part 20 of the atomizing body, the insert can be manufactured from various materials, including particularly metals in addition to semiconductor materials, glass and plastic. In the case of metal the cup-like, concave vaporizing space 17 is advantageously arranged in wall part 10 via punching. Such a concave form has an advantage relative to the cylindrical form applied in the previous example. This is because the outflow ports 18 in the concave form are always well aligned relative to each other so that the two liquid jets escaping therefrom will always strike each other properly. Although the overall jet pattern may then be slightly askew, this is not of real significance for many applications. In the case of other forms, such as a punched right angle or a cylindrical shape, the alignment is more critical.
For a practical final finishing the atomizing body 1 of an atomizing device, according to an embodiment of a second aspect of the invention, is supplied in an envelope 40, see
In this example the envelope comprises two shell parts 41,42 manufactured from a thermoplastic plastic, such as a polyamide or a polyolefin, for instance by injection moulding. The shell parts are both provided with cavities 44 and protrusions or pins 45, and fit precisely to each other, guided herein by a fitting of the pins or protrusions 45 in cavities 44. Both shell parts herein lie round a shared vaporizing cavity 43 in which an atomizing body can be received in at least substantially fitting manner.
According to an embodiment of a method according to the invention, the atomizing body is placed in one of the two envelope parts 41 in vaporizing cavity 43 and positioned accurately therein. Envelope part 41 is joined together with the second envelope part 42 in order to close the whole. The thus obtained assembly is then subjected to an electromagnetic radiation or laser radiation of a selected nature and frequency at a sufficiently high power to cause the temperature of the atomizing body to increase in contact-free manner.
In the present example use is made for this purpose of microwave radiation at a frequency of about 2.5 GHz and a power of about 800 W. Within just seconds this results in a temperature increase on a boundary surface with the atomizing body in the order of several hundred degrees Celsius. At such a temperature the two thermoplastic envelope parts 41,42 fuse on at least the boundary surface with the atomizing body into a non-releasable, leakage-free whole. The thus enveloped atomizing body can for instance serve as spray nozzle in the atomizing device. On an inlet side the spray nozzle 40 comprises a cavity 46 which is in open communication with an inlet 16 of the atomizing body, while the spray nozzle is open on a delivery side in order to leave clear a system of outflow ports of the atomizing body.
Instead of being formed from two at least substantially symmetrical shell parts, such an envelope can also be formed from a base part 51 and a cap 52 fitting therein. An exemplary embodiment hereof is shown in
Cap 52 also forms a spacer part which is able and adapted to maintain under all conditions a distance from the seating 53 in which atomizing body 1 is enclosed. Atomizing body 1 hereby lies sufficiently recessed and protected in envelope 51,52 in order to prevent the vulnerable outflow ports 8 of an atomizing body 1 being able to come into contact with a part of another atomizing device during storage or transport. Instead of a continuous edge, as in this example, the spacer part can also comprise one or more protrusions, ribs or other profile on the top of the envelope, or be formed by a sufficient wall length from the top of the envelope to seating 53.
It is otherwise also possible to make use of an envelope of only a single envelope part, in which the atomizing body is accommodated and fixed in similar manner. An exemplary embodiment of an atomizing body with such an envelope is shown in
In order to prevent an atomizing body, once it has been adhered in seating 53, later being pulled loose as a result of lateral shrink or expansion of a surrounding part 58 of the envelope, the seating is surrounded by an edge part 56 which is in turn separated by a groove 57 from the adjacent part 58 of the envelope. Groove 57 has a depth which is at least substantially equal to that of seating 53, for instance at least roughly two thirds as deep, and forms an effective interruption in pull in the unlikely event of lateral stress in envelope part 51.
Such a tension relief is also applied in the exemplary embodiment of an atomizing body according to the invention shown in
After being joined together in the manner indicated, the whole is subjected according to the invention to a suitable radiation source, whereby the atomizing body will be heated and will generate heat to the wall of the seating 53 with which it is in heat-exchanging contact. As a result hereof the material of the wall will melt round the atomizing body and enter into a durable and seamless adhesion therewith. The wall of seating 53 is in this case also formed by an edge part 56 which is separated from a further-removed part of the envelope by a surrounding groove 57 in order to provide pull relief as specified above. Groove 57 is here arranged on an underside, i.e. a side remote from a delivery side, of the atomizing body so that the delivery side can be completely flat and turbulences or other disruptions of said transverse longitudinal flow on the delivery side are limited to a minimum during operation. If desired, anchoring cavities (not shown) can be provided in atomizing body 1, for instance by etching such cavities therein, so that the melted envelope material penetrates therein and provides an additional adhesion.
Although the invention has been further elucidated above with reference to only a few exemplary embodiments, it will be apparent that the invention is by no means limited thereto. On the contrary, many more variations and embodiments are possible within the scope of the invention for the person with ordinary skill in the art.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2000726 | Jun 2007 | NL | national |
| Filing Document | Filing Date | Country | Kind | 371c Date |
|---|---|---|---|---|
| PCT/NL2008/050438 | 6/30/2008 | WO | 00 | 11/16/2010 |
| Publishing Document | Publishing Date | Country | Kind |
|---|---|---|---|
| WO2009/002178 | 12/31/2008 | WO | A |
| Number | Name | Date | Kind |
|---|---|---|---|
| 5358179 | Lund et al. | Oct 1994 | A |
| 6113013 | Sand | Sep 2000 | A |
| 7152808 | Jenkins | Dec 2006 | B2 |
| 7219849 | Hedger | May 2007 | B1 |
| 20070063076 | Gopalan | Mar 2007 | A1 |
| Number | Date | Country |
|---|---|---|
| 2 851 483 | Aug 2004 | FR |
| 2 271 301 | Apr 1994 | GB |
| 7-323545 | Dec 1995 | JP |
| 10-146978 | Jun 1998 | JP |
| 2006-62373 | Mar 2006 | JP |
| WO 9823382 | Jun 1998 | WO |
| WO 2005014175 | Feb 2005 | WO |
| WO 2007062726 | Jun 2007 | WO |
| WO 2007104561 | Sep 2007 | WO |
| Entry |
|---|
| International Search Report, dated Apr. 7, 2009, from corresponding PCT application. |
| Number | Date | Country | |
|---|---|---|---|
| 20110049262 A1 | Mar 2011 | US |
