WO2025095776A1

WO2025095776A1 - Trigger operated foam sprayer, sprayer head and foam nozzle therefor

Info

Publication number: WO2025095776A1
Application number: PCT/NL2024/050601
Authority: WO
Inventors: Paulo Nervo; Manouk Petronella Maria VERSCHURE
Original assignee: Dispensing Technologies BV
Current assignee: Dispensing Technologies BV
Priority date: 2023-10-30
Filing date: 2024-10-30
Publication date: 2025-05-08
Anticipated expiration: 2026-04-30
Also published as: NL2036149B1

Abstract

The invention relates to a trigger operated foam sprayer comprising, a reservoir, a foam nozzle, and a pump mechanism with a trigger. The foam nozzle has a foam outlet and a liquid inlet orifice at a distance from the foam outlet for creating a liquid jet in the direction of the foam outlet along a liquid path, the liquid inlet orifice defining a primary flow direction coinciding with a central axis of the orifice. The foam nozzle further comprises a baffle disposed in the liquid path, wherein the baffle comprises an impingement surface which is oriented at a first angle, which is an acute internal angle, with respect to the primary flow direction. The invention also relates to such a foam nozzle by itself.

Description

TRIGGER OPERATED FOAM SPRAYER, SPRAYER HEAD AND FOAM NOZZLE

THEREFOR

The invention relates to a trigger operated foam sprayer. In particular, the trigger operated foam sprayer is of a prolonged or continuous spraying kind. Such sprayers generally comprise a reservoir for containing a liquid to be foamed and a sprayer head connected to the reservoir. The sprayer head may comprise a pump mechanism and a trigger for operating the pump mechanism. Operation of the trigger causes the pump mechanism to eject liquid from the reservoir through a nozzle. The sprayer head of a foam sprayer generally also comprises a foam nozzle for creating a foam of the liquid upon ejection of the liquid through the nozzle.

Prolonged or continuous type trigger operated sprayers are known. As an example, trigger sprayers marketed by the applicant under the name Flairosol ® are capable of producing a prolonged or even continuous spray. For an example of such a sprayer, reference is made e.g. to US 9,714,133 B2 of the current applicant. In general, such trigger sprayers have a method of buffering energy introduced into the sprayer by movement of the trigger, and for releasing the energy over a prolonged or even continuous period of time until the trigger is no longer operated and the energy is slowly used up. The prolonged or continuous trigger sprayers are in general very well usable, and very popular since they allow easy application of various substances and give the spray impression comparable to that of an aerosol using a pressurized container.

Foam nozzles adapted for use with trigger sprayers in general are known, for instance from US 5,647,539 and US 4,463,905. However, the disclosed trigger sprayers in these documents are not prolonged or continuous trigger sprayers, and the foam nozzles proposed in them are not sufficiently adapted to create foam from such a sprayer.

In fact, it has been a challenge however, to dispense foam of a desirable quality from a sprayer of the above-described type, a challenge with which the current application may be concerned.

The foam nozzles of US 5,647,539 and US 4,463,905 each have a foam outlet and a liquid inlet orifice at a distance from the foam outlet.

US 4,219,159 discloses a foam-generating element for use in conjunction with a trigger-actuated dispenser. It includes a tubular foam forming chamber arranged between an orifice and a mesh. The foam forming chamber has a diameter that is substantially larger than that of the orifice. Two spaced apart parallel interrupter rings protrude radially inwardly from a wall of the foam forming chamber and are struck when the liquid spray fans out after leaving the orifice.

EP 0 505 571 Bl discloses a foaming nozzle having the shape of an elliptical cylinder mounted coaxially in the leading end portion of a spray nozzle of a sprayer. The foaming nozzle is intended to spray a foam having a cross-section of a transversely elongated band shape, which is adapted to spray a fungusproofing detergent in joints between tiles. In one embodiment, a pair of baffle plates protrude a short distance from opposite sides in the middle of a peripheral wall of the foaming nozzle to render the band of foam thinner in the middle and denser at the ends.

According to the invention, the liquid inlet orifice is adapted to create a liquid jet in the direction of the foam outlet along a liquid path. The liquid inlet orifice defines a primary flow direction which coincides with its central axis. The foam nozzle further comprises a baffle disposed in the liquid path, wherein the baffle extends in front of the liquid inlet orifice and comprises an impingement surface. The impingement surface intersects the central axis of the liquid inlet nozzle at a first angle, which is an acute internal angle.

The proposed foam nozzle has an entirely different operational principle than those of the prior art. In particular, the prior art nozzles function by creating a conically diverging spray of liquid from the orifice, and having the spray interact with a mesh. The conically diverging spray consists of many smaller droplets, each of which independently interacts with air to form a part of the foam which is ultimately dispensed through the mesh.

The foam nozzle as described herein however, does not create such a conically diverging spray of liquid from the orifice. In fact, the orifice is adapted to create a liquid jet which diverges in no more than one direction transversal to the primary flow direction. In particular, the liquid jet may be substantially unidirectional, may diverge in at most one direction to create a flat fan shape, and/or may not substantially diverge conically. Travelling along a liquid path which substantially coincides with the central axis of the liquid inlet orifice, the liquid jet impinges on the impingement surface of the baffle. This causes the jet to splash apart into droplets, which interact with air to form a foam. Due to the angle of the impingement surface, the jet is deflected, but allowed to pass towards the outlet in a deflected course towards the foam outlet.

This particular arrangement has the advantage that it is able to provide foam of a desirable quality even when the velocity of the liquid is relatively low. This makes the foam nozzle particularly desirable for e.g. continuous or prolonged trigger sprayers, which often have a lower liquid velocity than conventional trigger operated sprayers. Of course, the lower velocity may also be used in conventional trigger sprayers to e.g. facilitate dosing, reduce the amount of energy needed per unit time for dispensing, or prevent pressure build up in the liquid, or some other reason.

The liquid inlet orifice may be configured to produce a substantially unidirectional jet of liquid, i.e. one which does not substantially diverge, and is coherent. Alternatively, the liquid inlet orifice may be configured to produce a liquid jet diverging in exactly one direction transversal to the primary flow direction, i.e. a liquid jet that has a flat fan shape. The jet diverging in no more than one dimension means that the jet itself is one-dimensional or two-dimensional. Therefore, the liquid inlet orifice, either alone or in combination with its sprayhead, may be configured to create a one- or two-dimensional jet.

In both cases, the speed of the liquid is relatively high as compared to traditional nozzles which use conically, three-dimensional sprays coming from the orifice. It is believed this increased speed causes increased foaming performance in combination with a baffle as described herein. In that regard, it is noted that creation of a three-dimensional, e.g. conical spray pattern may significantly slow down the liquid.

In some trigger sprayers, a foam is made by using a relief in the area through which the liquid flows, either before or after the liquid inlet orifice, the relief being shaped to cause the liquid to spin or move even more chaotically, in order to cause it to diverge. In any case, as described herein the foam nozzle is configured, either in and of itself, in particular in combination with the sprayer head with which it cooperates, to create the unidirectional jet, which therefore does not diverge.

A relatively uniform spread of foam across the area in which the baffle causes it to dispense, can be achieved if the impingement surface of the baffle is substantially smooth. Smooth may herein be defined as absent of any channels, grooves, ribs or other such surface modifiers which would conventionally be used to cause spin or chaotic movement. Chaotic movement could for instance be caused by a surface having an angular profile. Therefore, such an angular profile may be absent. Depending on the liquid being dispensed, the required smoothness may differ, however the skilled person is readily able to decide for each liquid whether or not a surface modifier is present, i.e. effective in modifying the interaction with the liquid by locally changing the direction thereof, or whether the surface is considered smooth.

The impingement surface may be straight along at least a first direction along the impingement surface. In a second direction along the impingement surface, perpendicular to the first direction, the impingement surface may principally also be straight, so that the impingement surface is substantially flat. However, it is also possible that in this second direction the impingement surface is curved or angled as will be described below.

Accordingly, the baffle may cause the liquid jet to diverge, but not so much split into two or more separate jets or sprays. Of course, the baffle may be adapted in other ways to produce this effect. In general, it would be sufficient for the impingement surface to be oriented at the defined angle, so that liquid is substantially deflected into generally the same, diverging but not splitting spray of foam. The liquid jet created by the liquid inlet orifice is relatively narrow. This has the effect that the liquid, as it leaves the orifice, is surrounded not by more liquid, but by open space often filled with air. This increases already the air-liquid interaction and may therefore increase foaming performance.

In other words, the liquid jet may be free to move towards the baffle, and thereby not be slowed down by e.g. side walls of a channel, and may not in particular encounter a traditional flow resistance. After all, as the jet moves through the air, there is no properly defined flow influenced by the conduit, channel, etc. through which the liquid flows. Regardless, as a result of the jet being free to move, the liquid arrives at the baffle at a relatively large velocity, so that foaming performance may be further increased.

Sufficient space, to be filled e.g. with air, can be created if the nozzle defines a foam chamber into which the liquid inlet orifice debouches, and which holds the baffle and which opens in the foam outlet. The foam chamber may be larger in cross sectional area than the liquid jet. This may be established by comparing e.g. an average diameter of the liquid jet with a characteristic cross sectional dimension of the chamber, e.g. the diameter or diagonal, in the same plane.

The impingement surface of the baffle may be defined as that surface upon which the liquid jet impinges when the trigger sprayer is operated, i.e. when jet the is ejected from the liquid inlet orifice. In general, the impingement surface would extend to some extent in every direction around the area of impingement. The impingement surface may in particular extend at least in a direction pointing away from the liquid inlet orifice, as that is where the liquid will move after impingement. In other directions, the impingement surface may not be as relevant.

The liquid path is defined most clearly as it leaves the liquid inlet orifice, as it runs directly in the center of the jet made when the foam nozzle is operated. The liquid path continues until it reaches the baffle, and is then defined as a geometric center of the thus produced foam spray pattern. In general, the liquid path is thus a combination of at least two substantially straight lines, the first defined by the jet, the second defined by the liquid after it leaves the baffle.

The liquid inlet orifice defines the primary flow direction as coinciding with an axis running through the center of the orifice. Accordingly, the primary flow direction is contained within the beginning of the liquid path, at least there where it has just left the liquid inlet orifice.

In case of a unidirectional jet, the primary flow direction and the beginning of the liquid flow path coincide. In case of a two-dimensional, e.g. flat fan shaped jet, the primary flow direction coincides with the geometric center of the spray. To further increase foaming performance, the foam nozzle may further comprise a mesh at the foam outlet.

The mesh may increase air-liquid interaction, thereby creating a foam of a more desirable quality. The mesh may for instance span the foam outlet completely or partially.

The mesh may be arranged at a second angle, which is an non-zero internal angle, with respect to the impingement surface. In an embodiment, the mesh is oriented perpendicularly to the primary flow direction. A relatively compact sprayer may be thus obtained. The mesh may also be arranged at an acute angle with respect to the impingement surface. That is to say, the second angle may be acute. In particular, the second angle may be chosen as a right angle, so that the liquid leaving the baffle interacts with it from a head-on direction, which may increase efficacy of the mesh, for instance by avoiding slowing down the liquid too much.

The angles defined in this application may be defined, unless stated otherwise, as seen in a lengthwise cross-sectional plane along which the baffle runs, the cross-sectional plane intersecting the liquid inlet orifice and the foam outlet and including the central axis of the orifice.

In an embodiment, the baffle projects from a side wall of the foam nozzle and the impingement surface extends past the central axis of the orifice. An elegant design may be thus obtained, which can be manufactured by mass production techniques such as injection moulding.

The baffle may include a control surface on a side of the impingement surface directed away from the liquid inlet orifice, which control surface is oriented at a third angle, which is an obtuse internal angle, with respect to the impingement surface. The control surface may connect to the impingement surface along the liquid path.

As the liquid impinges the impingement surface, it is deflected and starts travelling along the impingement surface. By placing a control surface after the impingement surface, the direction at which liquid is ejected as foam can be controlled. The third angle may or may not be obtuse, but if it is the control surface may aid in redirecting the liquid closer to the primary flow direction.

The angle may be defined with respect to the control surface at e.g. a free end thereof and/or on a side opposite the impingement surface. It is principally possible to have the control surface curve or even be angled between the end at which the angle is defined, and its connection to the impingement surface.

The angle may be chosen so that the control surface, preferably at least at a free end thereof, is parallel to the primary flow direction. As a result, foam may be directed substantially straight through the foam nozzle, which allows for a relatively compact and/or elegant design. As an example, the foam may be sprayed horizontally when the liquid inlet orifice is also horizontal - which it tends to be in the prior art.

Another method to define the position of the control surface, which may be alternative or additional to the third angle as defined above, is using a fourth angle, which is an internal angle, between the control surface, preferably at least at a free end thereof, and an extension of the impingement surface on the other hand, the fourth angle being larger than the first angle.

Accordingly, the control surface can be tilted upwards with respect to the impingement surface thereby increasing the escape angle (tilting upwards) as desired.

The control surface may be relatively effective in controlling the liquid flow direction if a transition between the impingement surface and the control surface is rounded, e.g. to create a fillet. Such a smooth transition aids the liquid in following the control surface. Accordingly, any smooth transition is of course covered.

The baffle may comprise an angled edge at a free end thereof, preferably at a free end of a control surface if it is present.

The angled edge may constitute a relatively sharp end to the baffle, which encourages the liquid to detach from the baffle and spray out from the foam outlet. The edge being angled prevents the liquid from changing direction at the free edge, so that the direction imparted by the control surface is substantially maintained.

The angled edge may be formed for instance by angling back the rear of the baffle, so that the rear surface of the baffle and the control surface or the impingement surface meet at the angled edge, which may present an acute angle, e.g. a fifth angle.

The impingement surface may be curved or angled, preferably in a direction transversal to the primary flow direction.

The particular shape of the impingement surface in that direction may aid in spreading the liquid transversally.

Transversally may herein be defined as transversal to the primary flow direction. The up and down direction, which are perpendicular to the transversal direction, may run in the earlier-defined lengthwise cross sectional plane, so that the transversal direction is perpendicular to that plane.

In case a two-dimensional jet is created, it is preferred if the spray fans out in the transversal direction, and not in the up and down directions. Needless to say, the orientation of the foam nozzle with respect to the horizon is not necessarily relevant for the definition of its constituents. Therefore, the up and down direction are defined relative to the respective components, and not to the horizon per se.

In order to form a relatively compact foam sprayer, said curvature or angle may be concave.

On the other hand, the curvature or angle may also be convex. A convex curvature may aid in tilting upwards the foam as it exits the foam outlet.

The foam nozzle may further comprise an air supply passage. The air supply passage may help, and be configured for, supplying air to the liquid travelling through the nozzle to enhance foaming.

Typically, the air supply passage may extend from the exterior of the foam nozzle towards the liquid path, e.g. to inside the foam nozzle, so that air from the exterior can be entrained.

The air supply passage may be arranged in several manners, but it is most effective when it allows air to interact with the liquid when it impinges on the baffle.

In particular, the air supply passage may be placed in a position which is transversal to the liquid path, transversal being defined as before. In such a location, it may allow air to be entrained by the liquid flow, thereby facilitating more air entering the nozzle for better foaming.

To allow sufficient air to be present when the jet impinges on the baffle, as seen along the liquid path, the air supply passage may be arranged upstream of the impingement surface, i.e. closer to the liquid inlet orifice than the impingement surface.

The air supply passage may for instance be arranged in a side wall of the foam nozzle, such as a side wall forming a foam chamber, but may additionally or alternatively comprise an aperture in the baffle. In such a case, there is more freedom in the design of the nozzle to allow for air to enter the passage. In particular, an inlet of the air supply passage may be arranged closer to the foam outlet, or may even be part of the foam outlet.

In the latter case, when there is also a mesh, the air supply passage includes a part of the mesh. In this embodiment, the foam nozzle is less easily contaminated, as it requires at least less opening. Additionally or alternatively, a part of the mesh being used to let air in, may have the advantage that the thus formed air inlet is always open. The mesh itself is less likely to be clogged or otherwise contaminated, and may be cleaned by a user easily or regularly, and may also be cleaned automatically when foaming.

In an embodiment, a first distance is defined from the liquid inlet orifice to a free end of the baffle, and a second distance is defined between the free end of the baffle and the foam outlet. The first distance is larger than the second distance, preferably at least 5 times larger, more preferably at least 8 times larger, most preferably at least 10 times larger.

The applicant has found that a sufficiently large first distance as compared to the second distance increases foaming performance. The distances (first and second) may be measured along the primary flow direction.

The foam nozzle may be an insert or attachment part for attachment on a sprayer head of the trigger sprayer. Accordingly, the foam nozzle may be manufactured separately, from one or more parts, to be attached to a sprayer head. This may allow design optimization for mass production. Moreover, it may allow use of readily available sprayer head designs, augmented with the foam nozzle as described herein to create superior performing foam sprayers relatively quickly.

In an embodiment the sprayer head comprises a projection aligned with the liquid inlet orifice of the foam nozzle in a connected state of the nozzle, the liquid inlet orifice being arranged at a nonzero distance from the projection to form a chamber before the liquid inlet orifice.

The projection may be used to feed liquid along that projection towards the liquid inlet orifice. By allowing a non-zero distance between the projection and the inlet orifice, any chaotic or twisting effect imparted on the flowing liquid by the projection can be negated or diminished, so that the liquid inlet orifice may be better able to produce a unidirectional, non-diverging jet. Due to the presence of the non-zero distance, existing sprayer heads - even those with spin groves on head face of the projection - can be used with the foam nozzle described herein. The twist effect of the channel may be adequately or largely countered.

In the connected state, the foam nozzle may be inserted into, attached to or onto, or otherwise mounted to the sprayer head.

The invention also relates to a sprayer head for use in the trigger sprayer as described above. Moreover, the invention relates to a foam nozzle for use in the trigger sprayer and/or in the sprayer head as defined above. The associated advantages discussed previously apply to the sprayer head and to the foam nozzle mutatis mutandis.

The invention will be further elucidated with reference to the figures, in which:

Figure 1 shows schematically a cross sectional view of a prior art spray head with a foam nozzle; Figure 2A shows schematically a perspective view of a prior art foam nozzle, and figure 2B shows schematically a head on view of a prior art foam nozzle;

Figures 3A - 3D each show schematically presentations of the operational principle of the currently described foam nozzle and trigger operated sprayer;

Figures 4A and 4B each show schematically a cross sectional view of a spray head with a foam nozzle and that foam nozzle respectively;

Figures 5A and 5B each show schematically a cross sectional view of another spray head with an accompanying foam nozzle and that foam nozzle respectively;

Figure 6 shows schematically variations of foam nozzles;

Figures 7A - 7E show schematically more variations of foam nozzles;

Figures 8A - 8D each shows schematically a cross sectional view of variations of a foam nozzle, in which measurements are indicated;

Figures 9A - 9E each show schematically a cross sectional view of more variations of a foam nozzle; and

Figures 10A - 10B each show schematically a cross sectional view of still more variations of foam nozzle.

Throughout the figures, like elements have been referred to using like reference numerals. Like elements of different embodiments, examples or variations are referred to using the same reference numeral increased by one hundred (100), unless otherwise indicated.

Figure 1 shows a part of a trigger sprayer 1 with a sprayer head 4 and a foam nozzle 7 connected thereto, both of which are known from the prior art. The sprayer head 4 includes a threaded part 2 for connection to a reservoir (not shown) such as a bottle, can, or other kind of container. A dip tube 3 is provided to reach into the container and suck up liquid for dispensing. A pump mechanism 6 is operated by a trigger 5 to cause liquid to move through the dip tube 3 into the foam nozzle 8. The pump mechanism 6 is not described in detail, as many different pump systems are known and can be combined with the current disclosure. In the sprayer head 4 shown, a projection 8 is present for the liquid to flow around and along before reaching a liquid inlet orifice 9 of the foam nozzle 7. From the liquid inlet orifice 9 the liquid is sprayed through the foam outlet 10.

The prior art foam nozzle 7 may work in one of two ways, which are shown in more detail in figures 2A and 2B. In figure 2A, a nozzle is shown that has spin grooves 11 at the end face of its projection 8. The spin grooves are fed by inlet channels 98 along the projection 8, and lead to a spin chamber 99. Liquid forced to flow along the projection 8 enters the spin grooves 11 and gains a spinning, sometimes turbulent or chaotic character in the spin chamber 99, which causes it to exit the foam nozzle 7 in a conically diverging spray pattern, but also to mix with air in a pipe portion 12 of the foam nozzle 7 at the same time to create a foam. For adequate foaming performance, a nozzle configured in this way requires liquid flow of a relatively high speed. Otherwise, the spinning and/or turbulent or chaotic motion does not cause sufficient mixing with air because it does not sufficiently break up the liquid in droplets. Another example foam nozzle 7’, using reference numbers with an apostrophe for like elements, is shown in figure 2B. Figure 2B is a view into back of the nozzle 7’, shown without the projection . This renders visible four specifically shaped bodies 13 inside the nozzle, defining between them spin grooves 14 which direct liquid entering the nozzle 7’ inwards into a spin chamber 99’. From there, the liquid exits the spin chamber 99’ through the liquid inlet orifice 9’ to create a foam. The result is a turbulent spray which causes mixing with air, and which exits the inlet orifice 9’ in a three dimensional, conical spray pattern. Like the example of figure 2A, this configuration requires a relatively high liquid speed.

Figure 3A shows the principle employed in the current disclosure to create a foam spray. In general, a liquid jet 16 is created. The liquid jet may be unidirectional, i.e. not substantially diverging, or may be two-dimensional, i.e. diverging in one direction, but not in another creating a substantially flat fan shape. A housing 15 is shown in cross section, but as is visible the jet 16 does not touch the walls of the housing 15. In fact, the housing 15 is much wider than the jet 16, so the jet can move downwards (in figure 3A) along the housing 15 without losing much speed. Further downwards, the housing 15 forms a baffle 17 upon which the liquid impinges. The impinging causes the liquid to disperse to the left in a foam spray 19. In this example, although not strictly required, an air passage 18 is provided upstream of the baffle 17, so that air can be sucked in to interact with the jet as and after it impinges. Figure 3B shows a top view of the same configuration, which makes clear baffle causes the foam spray 19 to spread horizontally, i.e. to fan out.

It is principally possible to use a unidirectional, non-diverging jet 16 as shown in figures 3A and 3B. However, a jet 16’ that is in the shape of a flat fan, i.e. diverging in one dimension but not another, can also be used. In figures 3C and 3D this is shown, firstly from a top view of a nozzle, which may or may not have a protrusion 50 similar to protrusion 8, but which includes a liquid inlet orifice 52 in a wall 51. The liquid inlet orifice has a passage width w, much larger than a passage height h. The passage height h can be seen in the cross sectional side view of figure 3D. As is shown, the nozzle 52 causes the jet 16’ to spread out in the transversal direction (see figure 3C) but not in the up-down direction (see figure 3D). Accordingly, a two dimensional jet 16’ is created. The jet 16’ impinges on a baffle 17’, which is principally similar to the baffle 17 of figures 3A and 3B, to cause foaming to occur. It is of course possible to use any suitable technique for creating jets, rather than that shown here.

Figure 4A shows a trigger sprayer 101 which is similar to that of figure 1, but which includes features of the invention. In figures 4A and 4B, and following figures shows cross sections of sprayer heads and foam nozzles, only the most important parts are hatched. The sprayer head 104 of figure 4A differs from that of figure 1 in that it has an alternative foam nozzle 107. The foam nozzle 107 is shown in more detail in figure 4B. Figure 4B shows that the foam nozzle 107 has a liquid inlet orifice 109 and a foam outlet 110. The foam nozzle 107 is disposed around a projection 108, but the liquid inlet orifice 109 is disposed at a distance 121 at a distance therefrom. The distance 121 is not strictly required, but aids in avoiding spinning effects, for instance caused by the shape of the projection 108. In the currently shown example, a projection 108 with a spin chamber 199 is used. However, due to the distance 121 the spinning effect caused by the projection 108 is negated or reduced. As a result, the liquid inlet orifice 109 creates a better substantially unidirectional jet of liquid. Since the jet of liquid is unidirectional, it corresponds to the primary liquid flow direction 122, which in turn coincides with a central axis A of the liquid inlet orifice 109. After leaving the liquid inlet orifice 109 the jet follows the primary flow direction 122 along a liquid path. A baffle 120 is disposed in the liquid path in front of the orifice. The baffle is oriented at a first angle a (see later figures) with respect to the primary liquid flow direction 122 and intersects the central axis A at this first angle a. The first angle a is an acute internal angle. The liquid jet impinges on the baffle 120 at an impingement surface 131 thereof. After impinging, the liquid spreads out and moves generally along the baffle 120 to a free end thereof towards the foam outlet 110. In the meantime, due to impinging, the jet is broken up into droplets which interact with air to form a foam. Foaming is then increased using a mesh 124 spanning the foam outlet 110.

Along the baffle 120, downstream of the impingement surface 131, a control surface 132 is arranged. The control surface 132, at least the part thereof at the free end of the baffle 120, is at an angle with respect to the impingement surface 131. The transition between the impingement surface 131 and the control surface 132 is rounded to create a fillet, but can in general otherwise be smooth, so it displays a curvature 135. The control surface 132 causes the liquid to curve upwards (as seen in figure 4B) since it tends to follow the surface of the control surface 132. Accordingly, the liquid path is continued in a somewhat horizontal direction 123 after the control surface. Of course, since the liquid is at this time foaming, and because it has impinged on the baffle 120, the spray is much more dispersed than it was before impingement. The liquid flow path 123 is therefore less well defined, but in the geometric center of the foam pattern it may be affected by the control surface 132 as desired, for instance by curving the control surface 132 upwards with respect to the impingement surface 131. The orientation of the control surface 132 may be defined using an angle P between the control surface 132 and the impingement surface 131, as will be shown later. The angle is an obtuse internal angle in the example of figures 4A and 4B, but other angles may be chosen. In the currently shown example, the control surface 132 is parallel to the primary flow direction 122. However, it would also be possible to point the control surface 132 further upwards (as shown in figure 8C). The liquid is caused to detach from the baffle 120 by angling back a rear side 133 thereof. The rear side 133 meets the control surface 132 at an angled edge 134, which cause a relatively abrupt change in shape of the baffle, which the liquid cannot easily follow. As a result, the liquid detaches and continues on towards the foam outlet 110. The angled edge 134 can also be provided without control surface 132, by letting the impingement surface 131 and the rear side 133 meet at the angled edge 134.

The foam nozzle 107 is manufactured from two separate parts to facilitate injection moulding. A first part is a base part 126 which can be connected to the sprayer head 104 by extending over the projection 108 thereof. A front part 125 is in turn placed inside the base part 126. The base part 126 in this case defines the liquid inlet orifice 109, whereas the front part 125 defines the baffle and the foam outlet 110. The front part 125 in this case is substantially tubular, although that is not required, and the baffle 120 protrudes into the liquid path from a side wall of the front part 125.

The foam nozzle 107 also comprises an air supply passage 127, which in this case is arranged upstream of the impingement surface 131. The air supply passage 127 is arranged in a side wall of the base part 126, and is unobstructed by the front part 125. Of course, the air supply passage 127 could be arranged elsewhere, but it is beneficial if it allows a flow of air from the exterior towards the jet at or near the liquid inlet orifice 109, or at least upstream of the baffle 120. It is possible to arrange the supply passage transversal to the jet, but it may be placed in any position radially away from the primary flow direction 122.

The foam nozzle 107 essentially defines a foam chamber, in which the liquid inlet orifice 109 debouches. The baffle 120 is placed in the chamber, and the chamber opens to the foam outlet 110. The foam chamber is relatively large with respect to a cross sectional area of the jet before it impinges. As a result, air is present around the jet, to allow interaction between the two.

Figures 5 A and 5B shows a trigger sprayer 201 and foam nozzle 207 similar to that of figures 4A and 4B. Only the differences will be described for the sake of brevity. Instead of a traditional trigger sprayer, the trigger sprayer 201 of figure 5 A is of the continuous type, meaning that it can create a continuing spray when repeatedly operated. For this purpose, the trigger sprayer 201 includes the trigger head 204 with a trigger 205 which operates a pump mechanism 206, and a body 202 which can connect to a container (not shown). A dip tube 203 is also provided. Most importantly, the trigger head 204 includes a buffering means 230 in which liquid can be accommodated under pressure to allow continuous spraying. The exact operation of the trigger sprayer 201 is not addressed in detail, as several continuously spraying sprayers are known from the art, and they can be combined with the foam nozzle 207 as described herein as desired. The foam nozzle 207 itself (see for details figure 5B) is also similar to that of figure 4B, apart from having an extension 243 for cooperation with the sprayer head 204, and the position of the air supply passage 227, which in this case is directly after the liquid inlet orifice 209, transversally to the side.

It is however noted that substantial freedom exist in the design of the foam nozzle. For that reason, variations which can be applied across all examples, are shown in figure 6. Elements of previously presented variations are indicated with the same reference numeral suffixed with a letter in this figure. First, the foam nozzle 207 of figure 5B is shown (left two images in figure 6). Arrow V in the leftmost figure shows the view axis of the figures to the right, where the nozzle 207(A-C) is shown without a mesh 224. The foam nozzle 207 has, as seen in a head-on view into the nozzle 207 a planar impingement surface 231 of the baffle 220. The planar surface 231 can however be rotated around the primary flow direction, as seen in variations 207A, 207B and 207C. Each orientation would allow the foam to exit the foam outlet 210 a little differently, so that the design of the foam nozzle 207 is relatively flexible.

Further variations, which can also be applied to all examples shown herein, are shown in figures 7A - 7E. Elements of previously presented variations are indicated with the same reference numeral suffixed with a letter across these figures. Whereas in its simplest form (figure 7A) the impingement surface 231 is planar (i.e. flat), it is also possible to curve the impingement surface 231A, 23 IB either concavely 231A or convexly 23 IB, confer figures 7B and 7C respectively. Figures 7D and 7E both show the impingement surface 231C, 23 ID being angled, either convexly 231C or concavely 23 ID.

Figure 8A shows a foam nozzle 307 which is identical to that of figure 5B, but without the extension 234 of that foam nozzle. Figure 8A is used to show some dimensions that can be and are used for the examples in this application. For an explanation of the features of the foam nozzle 307, reference is made to the description of figures 5B and 4B. Figure 8A further shows a first angle a between the impingement surface 331 and the primary flow direction 322, as an acute internal angle. A second angle P spans between the impingement surface 331 and the mesh 324, and is also an acute internal angle. If no mesh 324 is provided, the second angle may be defined with respect to the plane of the foam outlet instead. A third angle y is indicated between the control surface 332 and the impingement surface 331. Finally, a fourth angle 5 is indicated between the control surface 332 and an extension of the impingement surface 331, also as an acute internal angle. The liquid inlet orifice 309 has a diameter defined as o. Other dimensions are the diameter d of the foam outlet 310, the height y until where the baffle 320 extends, and a first distance Li measured between the liquid inlet orifice 309 and a free end of the baffle 320, and a second distance L2 measured between the free end of the baffle 320 and the foam outlet 310. The first distance Li is larger than the second distance L2. Reference will be made to these measurements in the examples, in which suitable numerical values will be shown.

Variations of the foam nozzle 307 of figure 8A will now be explained, by indicating only the differences with respect to the foam nozzle 307 of figure 8A.

Figure 8B shows a foam nozzle 407 identical to that of figure 8A, except for the fact that the control surface 432 and the impingement surface 431 now meet at an edge 435 instead of a curvature.

Figure 8C shows a foam nozzle 507 identical to that of figure 8A, except for that the control surface 532 is angled upwards, so that the fourth angle 5 is larger than the first angle a. This causes the foam to exit the foam outlet 510 in a more upwards direction. An angle e between the control surface 532 and the rear side 533 of the baffle 520 is also defined. The curvature between the control surface 532 and the impingement surface 531 is indicated with letter r.

Figure 8D shows a foam nozzle 607 identical that that of figure 8A, except for that no control surface is provided. Instead the impingement surface 631 continues unchanged until the free end of the baffle 620. This causes a relatively low exit of foam from the foam outlet.

Even more variations are possible, as exhibited in figure 9A, which shows a solid baffle 720 with a body 736 to create a relatively sturdy baffle 720 that may exhibit predictable dynamical behaviour when impinged by a jet. In this example no air inlet passage is present, which is a variation that may be applied to other variations alone or together with the solid baffle 720 having the body 736. The body 736 protrudes from the side wall of the foam nozzle 707, and has a front 737 and back 738 both of which are outside of the liquid flow path. The body extends between the front 737 and back 738 and fills the space completely, and it forms the impingement surface 731.

With reference to figure 9B, it is noted that air inlet passage 827 can also be made in e.g. the front part 825 of the foam nozzle 807. The base part 826 can in that case exhibit solid wall 840 without any perforations or recesses, as they are not needed for forming the air supply passage 827. As a further variation, the front part 825 is in this example provided over the base part 826 instead of inside it. This shows that in general, even across other variations, the front and base part 825, 826 can be attached in any suitable way, such as one inside the other or vice versa. These variations are independent of the position of the air supply passage 827. Also, the curvature between impingement surface 831 and control surface 832 is replaced by an edge 835. This is also the case in figures 9C - 9E described below.

With reference to figure 9C, it is noted that the air supply passage 927 can also be created by a suitable recess in the side wall of the front part 925 and the base part 926 or one of both, although the latter is not shown. In any case, no aperture needs to be made in the parts 925, 926 themselves, instead the air supply passage 927 may allow air to pass (see A) in between the front part 925 and the base part 926. As an alternative to the variation of figure 9C, the air supply passage can also be provided in the baffle, as is shown in figure 9D. Here, an aperture 927’ is present in the baffle 920’, which allows air to proceed upstream of the baffle 920’. The air may come from an upper part 941 ’ of the foam outlet 910’ whether or not it is provided with a mesh 924 ’ . In both cases, the front part 925, 925’ is provided over the base part 926, 926’.

With reference to figure 9E it is noted that the foam nozzle 1007 may have any suitable shape. In this figure, it is shown that the foam outlet 1010 can have a center line deviating from the primary flow direction 1022 with a distance L3, so that a larger space is available for foaming, and so that the foam may exit in approximately the middle of the foam outlet 1010. An air inlet passage 1027 similar to that of figure 9C is provided. Again, the front part 1025 is provided over the base part 1026.

Figures 10A and 10B show variations in which the foam nozzle 1107, 1207 is angled, so that an outflow direction 1144, 1244 is at a non-zero angle with respect to the primary flow direction 1122, 1222. This is achieved by creating an angle 1143, 1243 in the front part 1125, 1225. In figure 10A, the baffle 1120 is oriented so that its impingent surface 1131 is parallel to the outflow direction 1144, whereas in figure 10B it remains somewhat tilted downwards to increase the first angle a. Spray direction is controlled by the provision of a control surface 1232 at a fourth angle 5.

EXAMPLE

The foam nozzle in figure 8A was manufactured using 3D printing. Testing gave desirable foam performance. The foam was dry and relatively dense.

The dimensions of the foam nozzle were as follows:

First distance Li: 6.6 mm

Second distance L2: 0,5 mm height y: 1.8 mm diameter d: 4.5 mm orifice o: 0.28 mm radius of curvature r: 2 mm first angle a 25° second angle 65° third angle y 155° fourth angle 5 25° Depending on the liquid to be dispensed as a foam, these dimensions may be particularly desirable.

However, the foam nozzle is expected to operate also in the following cases.

The first distance Li can be between 2 and 20 mm, preferably between 5 and 10 mm, more preferably between 6 and 10 mm, such as around 6.6 mm.

The second distance L2 may be between 0,1 and 10 mm, preferably between 0,3 and 5 mm, more preferably between 0,3 and 1 mm, such as around 0,5 mm. As defined above, the second distance L2 may be smaller than the first distance Li.

The height y may be larger than 1 mm, preferably larger than 1.5 mm, such as around 1,8 mm. suitable upper bounds can be chosen, such as 2 mm, 5 mm or even 10 mm.

The diameter d may be between 2.5 and 25 mm, preferably between 4 and 15 mm, more preferably between 4 and 10 mm, such as around 4.5 mm.

The orifice o may measure between 0.10 and 1.5 mm, preferably between 0.20 and 1.0 mm, more preferably between 0.25 and 0.5 mm, such as around 0.28 mm.

The radius r may be larger than 0 mm, such as larger than 1 mm, preferably around 2 mm, or even larger.

The first angle a may be between 5° and 75°, preferably between 15° and 50°, more preferably between 20° and 30°, such as around 25°.

The second angle may be the difference between 90° and the first angle a, and/or may be between 10° and 100°, preferably between 30° and 80°, such as around 65°.

The third angle y may be the difference between 180° and the first angle a, and/or may be between 100° and 200°, preferably between 130° and 170°, such as around 155°.

The fourth angle 5 may be between 5° and 75°, preferably between 15° and 50°, more preferably between 20° and 30°, such as around 25°.

The fifth angle e defining the position of the rear surface of the baffle, may be smaller than 120°, preferably smaller than 100°, such as smaller than 90°. The fifth angle e may be larger than 0°.

The present invention is not limited to the embodiments, examples and variations shown, but extends also to other embodiments falling within the scope of the appended claims. Thus, it should be considered that variations shown together or alone, can also be combined with other variations, as is covered by the attached claims.

Claims

1. Trigger operated foam sprayer, preferably of the prolonged or continuous spraying kind, the sprayer comprising:

- a reservoir for containing a liquid to be foamed; and

- a sprayer head connected to the reservoir, the sprayer head comprising:

- a foam nozzle for creating a foam of the liquid upon ejection of the liquid through the nozzle; and

- a pump mechanism and a trigger for operation the pump mechanism, wherein operation of the trigger causes the pump mechanism to eject liquid from the reservoir through the foam nozzle, wherein the foam nozzle has a foam outlet and a liquid inlet orifice at a distance from the foam outlet for creating a liquid jet in the direction of the foam outlet along a liquid path, the liquid inlet orifice defining a primary flow direction which coincides with a central axis of the orifice, and wherein the foam nozzle further comprises a baffle disposed in the liquid path, wherein the baffle extends in front of the orifice and comprises an impingement surface which intersects the central axis of the orifice at a first angle, which is an acute internal angle.

2. Trigger sprayer according to claim 1, wherein the foam nozzle further comprises a mesh at the foam outlet.

3. Trigger sprayer according to claim 2, wherein the mesh is at a second angle, which is a non-zero internal angle, with respect to the impingement surface.

4. Trigger sprayer according to any one of claims 1-3, wherein the baffle projects from a side wall of the foam nozzle and wherein the impingement surface extends past the central axis of the orifice.

5. Trigger sprayer according to any one of the preceding claims, wherein the baffle includes a control surface on a side of the impingement surface directed away from the liquid inlet orifice, which control surface is oriented at a third angle, which is an obtuse internal angle, with respect to the impingement surface.

6. Trigger sprayer according to claim 5, wherein the control surface, preferably at least at a free end thereof, is parallel to the primary flow direction.

7. Trigger sprayer according to claim 5, wherein a fourth angle, which is an internal angle between the control surface, preferably at least at a free end thereof, and an extension of the impingement surface, is larger than the first angle.

8. Trigger sprayer according to any one of claims 5 - 7, wherein a transition between the impingement surface and the control surface is rounded.

9. Trigger sprayer according to any one of the preceding claims, wherein the baffle comprises an angled edge at a free end thereof, preferably at a free end of a control surface if it is present.

10. Trigger sprayer according to any one of the preceding claims, wherein the impingement surface is curved or angled, preferably in a direction transversal to the primary flow direction.

11. Trigger sprayer according to claim 10, wherein the curvature or angle is concave.

12. Trigger sprayer according to claim 10, wherein the curvature or angle is convex.

13. Trigger sprayer according to any one of the preceding claims, wherein the foam nozzle further comprises an air supply passage.

14. Trigger sprayer according to claim 13, wherein the air supply passage is placed in a position which is transversal to the primary flow direction.

15. Trigger sprayer according to claim 13 or 14, wherein as seen along the liquid path, the air supply passage is arranged upstream of the impingement surface.

16. Trigger sprayer according to any one of claims 13 - 15, wherein the air supply passage includes an aperture in the baffle.

17. Trigger sprayer according to any one of claims 13 - 16, including the mesh of claim 2, wherein the air supply passage includes a part of the mesh.

18. Trigger sprayer according to any one of the preceding claims, wherein a first distance is defined from the liquid inlet orifice to a free end of the baffle, and wherein a second distance is defined between the free end of the baffle and the foam outlet, and wherein the first distance is larger than the second distance, preferably at least 5 times larger, more preferably at least 8 times larger, most preferably at least 10 times larger.

19. Trigger sprayer according to any one of the preceding claims, wherein the foam nozzle defines a foam chamber into which the liquid inlet orifice debouches, and which holds the baffle and which opens in the foam outlet.

20. Trigger sprayer according to any one of the preceding claims, wherein the foam nozzle is an insert or attachment part for attachment on a sprayer head of the trigger sprayer.

21. Trigger sprayer according to any one of the preceding claims, wherein the sprayer head comprises a projection aligned with the liquid inlet orifice of the foam nozzle in a connected state of the nozzle, the liquid inlet orifice being arranged at a non-zero distance from the projection to form a chamber before the liquid inlet orifice.

22. Sprayer head for use in the trigger sprayer according to any one of the preceding claims.

23. Foam nozzle for use in the trigger sprayer according to any one of the preceding claims and/or for use in the sprayer head according to claim 22.