Milk foaming device equipped with a calibrated air passage

Abstract

The milk frothing device (2) comprises a mixing section (6) including a mixing chamber (13), a hot water / steam inlet port, and a main flow conduit connecting the hot water / steam inlet port to the mixing chamber (13); a closing section (27) movable relative to the mixing section (6) between a closed position in which the closing section (27) closes the mixing chamber (13) and the main flow conduit and an open position in which the mixing chamber (13) and the main flow conduit are open; a milk supply conduit (22) and an air supply conduit connected to the main flow conduit; and a sealing gasket (25) extending around the mixing chamber (13) and the main flow conduit. Figure 3

Description

Title of the invention: Milk frothing device provided with a calibrated air passage Technical field

[0001] The present invention relates to the field of automatic coffee machines, and more particularly to the field of milk frothing devices intended to cooperate with automatic coffee machines. State of the art

[0002] Document WO2005 / 063093 discloses a milk frothing device comprising:

[0003] - a mixing part comprising a mixing chamber provided with an orifice outlet, a steam inlet and a main flow conduit connecting the steam inlet to the mixing chamber,

[0004] - a closing part movable relative to the mixing part between a position closing position in which the closing portion closes the mixing chamber and the main flow duct and an open position in which the mixing chamber and the main flow duct are open and accessible for cleaning,

[0005] - a milk supply pipe connected to the main flow pipe,

[0006] - an air supply duct connected to the main flow duct, and

[0007] - a seal arranged at a junction zone between the mixing part and the closing portion and extending around the mixing chamber and the main flow conduit.

[0008] The main flow duct is more particularly configured such that a flow of steam in the main flow duct from the steam inlet orifice and to the mixing chamber generates a vacuum in the milk supply duct and a vacuum in the air supply duct and causes a suction of milk and air into the main flow duct.

[0009] The particular configuration of the milk frothing device described in document WO2005 / 063093, and more particularly of the mixing part and the closing part, allows easy cleaning of the milk frothing device.

[0010] However, according to document WO2005 / 063093, the seal is formed by a covering piece, which is generally flat and which is made of flexible material, and the milk supply duct, the main flow duct and the mixing chamber are partly delimited by said covering piece. Thus, the milk proteins, contained in the milk flowing in the milk supply duct milk and the main flow duct, are likely to deform the covering part and therefore modify in particular the passage section of the main flow duct.

[0011] However, such a modification of the passage section of the main flow duct is likely to modify, over time, the quantity of air introduced into the main flow duct, which can lead to obtaining a milk foam having a consistency which is not firm and creamy enough, and for example too liquid. Summary of the invention

[0012] The present invention aims to remedy all or part of these drawbacks.

[0013] The technical problem underlying the invention consists in particular in providing a milk frothing device which can be easily dismantled and cleaned, whilst guaranteeing that milk froth of an appropriate consistency is obtained.

[0014] To this end, the present invention relates to a milk frothing device intended to cooperate with an automatic coffee machine, the milk frothing device comprising:

[0015] - a mixing part comprising a mixing chamber provided with an orifice of outlet, a hot water / steam inlet and a main flow conduit connecting the hot water / steam inlet to the mixing chamber,

[0016] - a closing part movable relative to the mixing part between a position closing position in which the closing portion closes the mixing chamber and the main flow duct and an open position in which the mixing chamber and the main flow duct are open and accessible for cleaning,

[0017] - a milk supply pipe connected to the main flow pipe,

[0018] - an air supply duct connected to the main flow duct, and

[0019] - a seal arranged at a junction zone between the mixing part and the closing portion and extending around the mixing chamber and the main flow conduit.

[0020] The air supply duct comprises a calibrated air passage, for example annular, configured to define a maximum air flow rate in the air supply duct which is independent of the seal.

[0021] The presence of such a calibrated air passage makes it possible to avoid the admission of too large a quantity of air into the mixing chamber, and therefore the obtaining of a milk foam which is too aerated and / or provided with bubbles of large diameters.

[0022] Furthermore, the fact that the maximum air flow defined by the calibrated air passage is independent of the seal makes it possible to control the quantity of air admitted into the main flow duct, since such a quantity of air is not likely to be altered by milk proteins flowing into the main outflow duct.

[0023] Thus, the milk frothing device according to the present invention can be disassembled and cleaned easily, while ensuring that milk froth of an appropriate consistency is obtained.

[0024] The milk frothing device may further have one or more of the following features, taken alone or in combination.

[0025] According to one embodiment of the invention, the milk frothing device further comprises an air flow adjustment device configured to adjust an air flow flowing in the air supply duct. Such a configuration of the milk frothing device according to the present invention, and more particularly the presence of the air flow adjustment device, allows a user to adapt the consistency of the milk foam obtained according to his wishes. The user can for example adjust the air flow introduced into the mixing chamber in order to obtain a more or less firm milk foam.

[0026] According to one embodiment of the invention, the main flow duct is entirely delimited by the mixing portion and the closing portion. Thus, the milk proteins contained in the milk flowing in the main flow duct are not likely to deform the latter, and therefore to have an impact on the quantity of air introduced into the mixing chamber.

[0027] According to one embodiment of the invention, the air flow adjustment device comprises:

[0028] - a flow adjustment member, such as a flow adjustment knob, mounted movably, and for example mounted mobile in translation or even according to a helical movement, according to a direction of movement and configured to occupy a plurality of adjustment positions offset from each other according to the direction of movement, and

[0029] - a sealing element, for example annular, partially delimiting a passage air flow having a passage section which varies according to the position occupied by the flow adjustment member.

[0030] Such a configuration of the air flow adjustment device makes it possible to easily adjust the quantity of air introduced into the main flow duct by moving the flow adjustment member into an adjustment position corresponding to the desired foam consistency.

[0031] According to one embodiment of the invention, the calibrated air passage is located downstream of the air flow adjustment device, and for example downstream of the air flow passage.

[0032] According to one embodiment of the invention, the air flow adjustment device comprises at least one air intake opening, the air flow passage being configured to fluidly connect the at least one air intake opening to the calibrated air passage.

[0033] According to one embodiment of the invention, the flow rate adjustment member is movable between a maximum adjustment position in which the passage section of the air flow passage is maximum, and a minimum adjustment position in which the passage section of the air flow passage is minimum, and for example zero or substantially zero.

[0034] According to one embodiment of the invention, the air flow adjustment device comprises a support portion fixed to the closure portion and configured to support the flow adjustment member, the flow adjustment member being mounted to move relative to the support portion.

[0035] According to one embodiment of the invention, the sealing element is fixed to the flow rate adjustment member. Such an arrangement of the sealing element allows easy mounting of the air flow adjustment device.

[0036] According to one embodiment of the invention, the sealing element and the support portion delimit the air flow passage.

[0037] According to one embodiment of the invention, the at least one air intake opening is defined by a functional clearance between the flow adjustment member and the support portion.

[0038] According to one embodiment of the invention, the flow rate adjustment member comprises a manipulation part configured to be manipulated by a user so as to move the flow rate adjustment member in the direction of movement.

[0039] According to one embodiment of the invention, the support portion comprises an insertion hole, and the air flow adjustment device further comprises a passage restriction member, such as a pin or a needle, housed at least partly in the insertion hole, the insertion hole and the passage restriction member delimiting the calibrated air passage. Such a configuration of the calibrated air passage allows easy cleaning of the milk frothing device according to the present invention, and in particular of the calibrated air passage, by removing the passage restriction member from the insertion hole and then cleaning in particular the passage restriction member and the insertion hole.In addition, such a configuration of the calibrated air passage significantly limits the risks of obstruction of the calibrated air passage since the successive movements of the flow adjustment member in the direction of movement have the consequence of evacuating, from the calibrated air passage, any particles, such as dust particles, retained in the calibrated air passage.

[0040] According to one embodiment of the invention, the insertion hole has a diameter greater than one millimeter, preferably greater than 1.5 millimeters.

[0041] According to one embodiment of the invention, the passage restriction member comprises a lower end portion which is housed in the insertion hole.

[0042] According to one embodiment of the invention, the passage restriction member is elongated and extends in a direction of extension which is substantially parallel to the direction of movement.

[0043] According to one embodiment of the invention, the passage restriction member is integral in movement with the flow adjustment member. Thus, the passage restriction member is mounted to move in the insertion hole in the direction of movement.

[0044] According to one embodiment of the invention, the support part comprises a bearing surface, for example provided on an upper end face of the support part, which is annular and against which the sealing element is capable of being compressed.

[0045] According to one embodiment of the invention, the support part comprises a recess which is formed in the bearing surface provided on the support part and which partially delimits the air flow passage. The recess may, for example, extend radially relative to a central axis of the bearing surface.

[0046] According to one embodiment of the invention, the mixing part comprises an upper face in which the main flow conduit is arranged and into which the mixing chamber opens.

[0047] According to one embodiment of the invention, the mixing part comprises a receiving groove which is provided in the upper face of the mixing part and in which the sealing gasket is housed.

[0048] According to one embodiment of the invention, the mixing portion comprises a support wall which extends around the mixing chamber and the main flow duct and which partly delimits the receiving groove, the support wall projecting from the upper face of the support portion and the closing portion being configured to bear against the support wall. The presence of such a support wall limits the risks of milk leaking towards the seal, and therefore the risks of degradation of the latter by the milk proteins contained in the milk flowing in the main flow duct.

[0049] According to one embodiment of the invention, the mixing portion and the closing portion are generally circular and extend substantially coaxially when the closing portion occupies the closed position.

[0050] According to one embodiment of the invention, the mixing portion comprises an air intake channel configured to be closed by the closing portion, the air intake channel connecting the air supply duct to the main flow duct and the seal extending around the air intake channel.

[0051] According to one embodiment of the invention, the air intake channel is provided in the upper face of the mixing part.

[0052] According to one embodiment of the invention, the closing part comprises the air supply duct. Such an arrangement of the air supply duct makes it possible to substantially limit the risks of alteration of the air supply duct by the milk proteins contained in the milk flowing in the main flow duct, and therefore to guarantee the admission of a controlled quantity of air into the mixing chamber.

[0053] According to one embodiment of the invention, the junction zone is flat. Such a configuration of the milk frothing device according to the present invention allows easy assembly of the milk frothing device.

[0054] According to one embodiment of the invention, the mixing part comprises the milk supply conduit. Such an arrangement of the milk supply conduit makes it possible to substantially limit the risks of alteration of the milk supply conduit by the milk proteins contained in the milk flowing in the milk supply conduit, and therefore to guarantee the admission of a controlled quantity of milk into the mixing chamber.

[0055] According to one embodiment of the invention, the mixing part is in one piece.

[0056] According to one embodiment of the invention, the milk supply conduit comprises a calibrated flow passage configured to define a predetermined milk flow rate in the milk supply pipe. These arrangements ensure that a predetermined quantity of milk is admitted into the mixing chamber, and therefore that milk foam of an appropriate consistency is obtained.

[0057] According to one embodiment of the invention, the predetermined milk flow rate defined by the calibrated flow passage is independent of the seal. As a result, the quantity of milk admitted into the main flow conduit is independent of the seal, and is not likely to be altered by milk proteins flowing into the main flow conduit.

[0058] According to one embodiment of the invention, the main flow duct comprises a section restriction forming a milk and air suction system based on the venturi effect. In other words, the main flow duct is configured such that a flow of hot water / steam in the main flow duct from the hot water / steam inlet and into the mixing chamber generates a vacuum in the milk supply duct and a vacuum in the air supply duct and causes milk and air to be sucked into the main flow duct. Such a configuration of the milk frothing device makes it possible to control the amount of air and the amount of milk admitted into the mixing chamber, without requiring the presence of complex and expensive admission means.

[0059] According to one embodiment of the invention, the milk supply conduit opens into the main flow conduit near the section restriction.

[0060] According to one embodiment of the invention, the air intake channel opens into the main flow duct near the section restriction.

[0061] According to one embodiment of the invention, the main flow duct comprises:

[0062] - a first portion of conduit which is located upstream of the section restriction and which extends to the section restriction, the first portion of conduit having a passage section which decreases in the direction of the section restriction, and

[0063] - a second portion of conduit which is located downstream of the section restriction and which extends from the section restriction, the second portion of conduit having a passage section which increases towards the mixing chamber.

[0064] According to one embodiment of the invention, the main flow duct is configured to allow a first mixing of the steam, milk and air coming respectively from the hot water / steam inlet, the milk supply duct and the air intake channel, before their arrival in the mixing chamber.

[0065] According to one embodiment of the invention, the seal is continuous.

[0066] According to one embodiment of the invention, the seal has a section constant. The seal could however have a non-constant section to improve the seal between the mixing part and the closing part in the event of significant deformation of the latter.

[0067] According to one embodiment of the invention, the mixing chamber is of the cyclonic type and extends vertically, the main flow duct opening into an upper part of the mixing chamber and the outlet orifice being located in a lower part of the mixing chamber. Such a configuration of the mixing chamber promotes the mixing of air, milk and hot water or water vapor introduced into the mixing chamber.

[0068] According to one embodiment of the invention, the main flow duct opens tangentially into the mixing chamber. Such a configuration of the main flow duct promotes the mixing of air, milk and hot water or water vapor introduced into the mixing chamber.

[0069] According to one embodiment of the invention, the mixing portion comprises a milk discharge conduit fluidly connected to the outlet orifice of the mixing chamber and configured to be located vertically above a container, such as a cup.

[0070] According to one embodiment of the invention, the milk frothing device comprises a milk reservoir comprising an upper opening, the part of mixture being arranged at the upper opening, and is for example housed at least partly in the milk tank.

[0071] According to one embodiment of the invention, the mixing portion comprises a mixing body configured to partially close the milk reservoir and to be removable from the milk reservoir.

[0072] According to one embodiment of the invention, the mixing body is provided with a tubular mounting portion configured to be mounted in the milk tank, and more particularly to be inserted into the milk tank via the upper opening of the milk tank.

[0073] According to one embodiment of the invention, the closure portion is configured to cover the mixing portion.

[0074] According to one embodiment of the invention, the milk supply conduit comprises a milk suction tube extending vertically and opening into a lower part of the milk tank.

[0075] According to one embodiment of the invention, the calibrated flow passage is located downstream of the milk suction tube.

[0076] According to one embodiment of the invention, the mixing portion and the closing portion are configured to close the milk tank and to be removable from the milk tank. In other words, the mixing portion and the closing portion form a cover configured to close the milk tank.

[0077] According to one embodiment of the invention, the milk frothing device comprises a holding system configured to hold the closure portion in the closed position. Such a configuration of the holding system makes it possible to avoid untimely movement of the closure portion towards the open position.

[0078] According to one embodiment of the invention, the holding system is configured to ensure compression of the seal when the closing portion is in the closed position. Such a configuration of the holding system makes it possible to improve the effectiveness of the seal, and therefore to limit the risks of fluid leakage at the seal.

[0079] According to one embodiment of the invention, the holding system is configured to press the closure part against the mixing part when the closure part is in the closed position, so as to compress the seal, and more particularly a sealing lip of the seal.

[0080] According to one embodiment of the invention, the holding system comprises a locking part, such as a locking ring, mounted to move between a release position in which the locking part allows movement of the closing part towards the open position and a locking position in which the locking part prevents movement of the closing part. towards the open position. Such a configuration of the holding system allows a user to easily immobilize the closing part in the closed position.

[0081] According to one embodiment of the invention, the closing part comprises a filling opening and a flap movable between an open position in which the flap at least partially releases the filling opening and allows milk to be introduced into the milk tank and a closed position in which the flap at least partially closes the filling opening.

[0082] According to one embodiment of the invention, the mixing part comprises a passage opening configured to be located opposite the filling opening.

[0083] According to one embodiment of the invention, the holding system is configured to removably fix, i.e. temporarily and reversibly, the mixing part and the closing part to the milk tank.

[0084] According to another embodiment of the invention, the milk frothing device comprises a connecting device which is separate from the holding system and which is configured to removably, i.e. temporarily and reversibly, fix the mixing part and the closing part to the milk container.

[0085] According to one embodiment of the invention, the locking part is annular and is rotatable relative to the closing part around an axis of rotation and between the release position and the locking position.

[0086] According to one embodiment of the invention, the locking part comprises at least one fixing member, such as a fixing ramp, configured to cooperate with at least one fixing element, such as a fixing lug, configured to be integral in rotation with the mixing part, and for example provided on the mixing part or on the milk tank, the at least one fixing member being configured to cooperate with the at least one fixing element during a rotation of the locking part from the release position to the locking position so as to move the locking part towards the mixing part, the locking part being configured to move the closing part towards the mixing part during a rotation of the locking part from the release position to the locking position.

[0087] According to one embodiment of the invention, the locking portion comprises a bearing face configured to move the closing portion towards the mixing portion upon rotation of the locking portion from the release position to the locking position.

[0088] According to one embodiment of the invention, the locking part and the closing part form a sub-assembly.

[0089] According to one embodiment of the invention, the milk frothing device comprises an immobilization device configured to immobilize in rotation the mixing part relative to the milk reservoir when the mixing part is received in the milk reservoir.

[0090] The present invention further relates to an automatic coffee machine comprising a hot water / steam outlet nozzle, a boiler producing hot water and / or steam to supply said hot water / steam outlet nozzle, and a milk frothing device according to the present invention, the hot water / steam inlet of the milk frothing device being connected to the hot water / steam outlet nozzle.

[0091] By automatic coffee machine, it is understood that the coffee machine comprises in particular an infusion chamber which can be supplied with ground coffee by a grain grinder incorporated in the machine, or an infusion chamber which can receive a capsule or a coffee pod or an infusion chamber formed by a spoon intended to be filled with ground coffee and emptied manually. Brief description of the figures

[0092] The invention will be better understood with the aid of the description which follows with reference to the appended schematic drawings representing, by way of non-limiting example, an embodiment of this milk frothing device.

[0093] [Fig.l] is a top perspective view of a milk frothing device according to the present invention.

[0094] [Fig.2] is a top view of the milk frothing device of [Fig.l].

[0095] [Fig.3] is a perspective view, truncated longitudinally, of the device of milk frothing from [Fig.l].

[0096] [Fig.4] is a perspective view of a seal of the milk frothing device of [Fig.l].

[0097] [Fig.5] is a partial perspective view from above of the milk frothing device of [Fig.l].

[0098] [Fig.6] is a top perspective view of a mixing portion of the milk frothing device of [Fig.l].

[0099] [Fig.7] is a partial top view of the mixing portion of [Fig.6] fitted with the seal of [Fig.4].

[0100] [Fig.8] is a partial perspective view from above of the mixing portion equipped with the seal of [Fig.4].

[0101] [Fig.9] is a partial perspective view, truncated longitudinally, of the milk frothing device of [Fig.l].

[0102] [Fig. 10] is a partial perspective view, truncated longitudinally, of the part of mixing of [Fig.6].

[0103] [Fig. 11] is a perspective view from above of a subassembly of the device of milk frothing from [Fig.l].

[0104] [Fig. 12] is a bottom perspective view of the subassembly of [Fig. 11].

[0105] [Fig.13] is a bottom view of the subassembly of [Fig.11].

[0106] [Fig. 14] is a partial perspective view from above of a device for adjusting air flow rate of the milk frothing device of [Fig.l].

[0107] [Fig. 15] is a perspective view from above of a support portion and a member of passage restriction of the air flow adjustment device of [Fig. 14].

[0108] [Fig. 16] is a partial perspective view from above of the adjustment device of air flow of [Fig.14].

[0109] [Fig. 17] is a top sectional view of the air flow adjustment device of the [Fig.14],

[0110] [Fig. 18] is a perspective view of an automatic coffee machine equipped with the milk frothing device of [Fig.l]. Detailed description

[0111] Figures 1 to 18 show a milk frothing device 2 intended to cooperate with an automatic coffee machine 3.

[0112] The milk frothing device 2 comprises a milk reservoir 4 delimiting an internal volume intended to contain milk and comprising an upper opening 5. The milk reservoir 4 may for example have a generally cylindrical shape, and have a circular cross-section. However, the milk reservoir 4 could also have a completely different shape, and for example have an oblong or rectangular cross-section.

[0113] The milk frothing device 2 further comprises a mixing portion 6 arranged at the upper opening 5. The mixing portion 6 more particularly comprises a mixing body 7 provided with an upper face 8 which is generally planar. The mixing body 7 is configured to partially close the milk reservoir 4 and to be removable relative to the milk reservoir 4. The mixing body 7 may for example comprise a tubular mounting portion 9 configured to be mounted in the milk reservoir 4, and more particularly to be inserted into the milk reservoir 4 via the upper opening 5 of the milk reservoir 4.

[0114] Advantageously, the milk frothing device 2 comprises an immobilization device configured to immobilize in rotation the mixing body 7 relative to the milk reservoir 4 when the tubular mounting portion 9 is received in the milk reservoir 4. The immobilization device may for example comprise immobilizing ribs 11 provided on an upper peripheral edge of the milk tank 4 and distributed around a central axis of the milk tank 4, and immobilizing grooves 12 provided on the mixing body 7 and configured to cooperate respectively with the immobilizing ribs 11.

[0115] The mixing body 7 further comprises a mixing chamber 13 which opens into the upper face 8 of the mixing body 7 and which is provided with an outlet orifice 14, and furthermore a main flow duct 15 formed in the upper face 8 of the mixing body 7 and opening into the mixing chamber 13. According to the embodiment shown in the figures, the mixing chamber 13 is of the cyclonic type and extends vertically, and the main flow duct 15 opens tangentially into the mixing chamber 13. Advantageously, the main flow duct 15 opens into an upper part of the mixing chamber 13, and for example into a high point of the mixing chamber 13, and the outlet orifice 14 is located in a lower part of the mixing chamber 13, and is for example located at a low point of the mixing chamber 13.

[0116] As shown more particularly in [Fig.7], the main flow duct 15 comprises a section restriction 16 located for example in a central portion of the main flow duct 15, a first duct portion 15.1 which is located upstream of the section restriction 16 and which extends to the section restriction 16, and a second duct portion 15.2 which is located downstream of the section restriction 16 and which extends from the section restriction 16 and to the mixing chamber 13. Advantageously, the first duct portion 15.1 has a passage section which decreases in the direction of the section restriction 16, and the second duct portion 15.2 has a passage section which increases in the direction of the mixing chamber 13.

[0117] The mixing body 7 also comprises a connection end piece 17 configured to be connected to a hot water / steam outlet end piece of the automatic coffee machine 3, and more particularly to be fluidically connected to a boiler which equips the automatic coffee machine 3 and which is configured to produce hot water and / or steam. Advantageously, the connection end piece 17 extends radially relative to a central axis of the mixing body 7, and is configured to extend radially relative to the central axis of the milk tank 4.

[0118] The mixing body 7 further comprises a hot water / steam inlet orifice 21 which is fluidically connected to the connecting end piece 17 and which opens into the first conduit portion 15.1 and more particularly opposite the mixing chamber 13. The main flow conduit 15 is thus configured to fluidically connect the hot water / steam inlet orifice 21 to the mixing chamber 13, and to allow a flow of hot water / steam into the main flow conduit 15 and into the mixing chamber 13.

[0119] The milk frothing device 2 also comprises a milk supply conduit 22 fluidly connected to the main flow conduit 15, and therefore configured to be fluidly connected to the mixing chamber 13 via the main flow conduit 15. According to the embodiment shown in the figures, the mixing part 6 comprises the milk supply conduit 22, and more particularly the mixing body 7 and the milk supply conduit 22 are made in one piece.

[0120] As shown more particularly in [Fig. 3], the milk supply conduit 22 comprises a milk suction tube 22.1 extending vertically and opening into a lower part of the milk tank 4, and a calibrated flow passage 22.2 located downstream of the milk suction tube 22.1 and opening into the main flow conduit 15 at the section restriction 16. The calibrated flow passage 22.2 is more particularly configured to define a predetermined milk flow rate in the milk supply conduit 22.

[0121] According to the embodiment shown in the figures, the mixing body 7 further comprises an air intake channel 23 which is arranged in the upper face 8 of the mixing body 7 and which opens into the main flow duct 15 at the section restriction 16. The air intake channel 23 is thus configured to be fluidically connected to the mixing chamber 13 via the main flow duct 15.

[0122] The section restriction 16, described previously, induces an increase in the speed of the steam flowing in the main flow duct 15, which generates a depression in the milk supply duct 22 and in the air intake channel 23. The section restriction 16 is therefore more particularly configured to form a milk and air suction system based on the venturi effect. The main flow duct 15 is thus configured such that a flow of hot water / steam in the main flow duct 15 from the hot water / steam inlet 21 and into the mixing chamber 13 generates a vacuum in the milk supply duct 22 and a vacuum in the air intake channel 23 and consequently causes a suction of milk and air into the main flow duct 15 and a flow of the sucked milk and air into the mixing chamber 13. In addition, the second duct portion 15.2, which has a passage section which increases in the direction of the mixing chamber 13, promotes a first mixing of the steam, the milk and the air coming respectively from the hot water / steam inlet orifice 21, the milk supply duct 22 and the air intake channel 23, before their arrival in the mixing chamber 13.

[0123] The mixing body 7 further comprises a milk discharge conduit 24 fluidly connected to the outlet orifice 14 of the mixing chamber 13, and configured to allow discharge of hot milk and milk foam into a container, such as a cup, arranged vertically below the milk discharge conduit 24. Advantageously, the milk discharge conduit 24 is configured to extend radially relative to the central axis of the milk reservoir 4.

[0124] As shown more particularly in [Fig.4] and 7, the milk frothing device 2 comprises a seal 25 extending around the mixing chamber 13, the main flow duct 15 and the air intake channel 23. For this purpose, the mixing body 7 comprises a receiving groove 26 formed in the upper face 8 of the mixing body 7 and in which the seal 25 is housed.

[0125] According to the embodiment shown in the figures, the seal 25 comprises a seal body 25.1 housed entirely in the receiving groove 26, and a sealing lip 25.2 extending along the seal body 25.1 and projecting out of the receiving groove 26. Advantageously, the seal 25 is continuous and may for example have a constant section.

[0126] The milk frothing device 2 further comprises a closure portion 27 configured to cover the mixing body 7 and to bear against the mixing body 7. The mixing body 7 may optionally comprise a support wall 7.1 which extends around the mixing chamber 13 and the main flow duct 15 and which internally delimits the receiving groove 26, the support wall 7.1 projecting from the upper face 8 of the mixing body 7 and the closure portion 27 then being configured to bear against an upper edge of the support wall 7.1.

[0127] As shown in [Fig. 3], the closure portion 27 is generally planar, and the seal 25 is thus arranged at a junction area between the mixing portion 6 and the closure portion 27 which is generally planar. According to the embodiment shown in the figures, the mixing portion 6 and the closure portion 27 are generally circular and extend substantially coaxially with the central axis of the milk tank 4.

[0128] The mixing portion 6 and the closing portion 27 are configured to close the milk tank 4 and to be removable relative to the milk tank 4. The mixing portion 6 and the closing portion 27 thus form a cover configured to close the milk tank 4.

[0129] According to the embodiment shown in the figures, the closing part 27 comprises a filling opening 28 configured to be located opposite a passage opening 29 provided on the mixing body 7 and opening into the milk tank 4, and a flap 31 which is movable, and for example pivotally mounted, between a open position in which the flap 31 at least partially releases the filling opening 28 and allows milk to be introduced into the milk tank 4 and a closed position in which the flap 31 at least partially closes the filling opening 28.

[0130] The closing part 27 is more particularly mounted to be movable relative to the mixing part 6 between a closing position in which the closing part 27 closes the mixing chamber 13, the main flow duct 15 and the air intake channel 23, and an opening position in which the mixing chamber 13, the main flow duct 15 and the air intake channel 23 are open and accessible for cleaning.

[0131] Advantageously, the milk frothing device 2 also comprises a holding system 32 configured to hold the closure portion 27 in the closed position and to ensure compression of the seal 25 when the closure portion 27 is in the closed position. The holding system 32 is more particularly configured to press the closure portion 27 against the upper face 8 of the mixing body 7 when the closure portion 27 is in the closed position, so as to compress the seal 25, and more particularly the sealing lip 25.2 of the seal 25. According to the embodiment shown in the figures, the holding system 32 is also configured to removably fix, that is to say temporarily and reversibly, the mixing portion 6 and the closure portion 27 to the milk tank 4.However, such attachment of the mixing part 6 and the closing part 27 to the milk tank 4 could be achieved by a connecting device separate from the holding system 32.

[0132] As shown in [Fig.3], the holding system 32 comprises a portion of locking 33, such as a locking ring, mounted to rotate relative to the closing portion 27 about an axis of rotation A and between a release position in which the locking portion 33 allows movement of the closing portion 27 towards the open position and a locking position in which the locking portion 33 prevents movement of the closing portion 27 towards the open position. The axis of rotation A is advantageously substantially parallel to, and for example collinear with, the central axis of the milk tank 4 when the mixing portion 6 is received in the milk tank 4 and the closing portion 27 occupies the closed position.

[0133] According to the embodiment shown in the figures, the closing portion 27 is configured to occupy an intermediate position located between the closing position and the opening position and in which the closing portion 27 rests on the sealing lip 25.2 of the seal 25 and is therefore located opposite the mixing chamber 13 and the main flow duct 15 and is spaced from the mixing part 6, and the holding system 32 is configured to move the closing part 27 from the intermediate position to the closing position and towards the mixing part 6, and thus to bring the closing part 27 closer to the mixing part 6, when the locking part 33 is moved from the release position to the locking position.

[0134] As shown in Figures 5 and 12, the holding system 32 further comprises a plurality of fixing members 34, such as fixing ramps or fixing grooves, provided on the locking part 33 and distributed around the axis of rotation A, and a plurality of fixing elements 35, such as fixing lugs or fixing notches, provided on the milk tank 4 and distributed around the central axis of the milk tank 4. The fixing elements 35 are configured to cooperate respectively with the fixing members 34 provided on the locking part 33 during a rotation of the locking part 33 from the release position to the locking position, so as to move the locking part 33 towards the mixing part 6. The fixing members 34 and the fixing elements 35 may for example form a bayonet or screw-nut type fixing system.According to the embodiment shown in the figures, the fixing members 34 are provided on an inner surface of the locking part 33, and the fixing elements 35 are provided on an outer surface of the milk tank 4.

[0135] Advantageously, the locking portion 33 comprises a bearing face 36 (see in particular [Fig. 9]) which extends transversely to the axis of rotation A and which is configured to move the closing portion 27 towards the mixing portion 6 and parallel to the axis of rotation A during a rotation of the locking portion 33 from the release position to the locking position. The bearing face 36 is more particularly configured to slide on the closing portion 27 during a rotation of the locking portion 33 between the release position and the locking position. The bearing face 36 is annular and is configured to bear against a peripheral edge of the closing portion 27.

[0136] According to the embodiment shown in the figures, the locking part 33 is mounted in a captive manner on the closing part 27, such that the locking part 33 and the closing part 27 form a non-removable subassembly.

[0137] As shown more particularly in [Fig. 13], the milk frothing device 2 comprises an angular travel limiting device configured to limit an angular travel of the locking portion 33 relative to the closing portion 27. The angular travel limiting device may for example comprise one or more first end stop(s) 37 provided on the locking portion 33 and configured to prevent rotation of the locking portion 33, in a first direction of rotation, beyond the release position, and one or more second end stop(s) 38 provided on the locking portion 33 and configured to prevent rotation of the locking portion 33, in a second direction of rotation, beyond the locking position.

[0138] Advantageously, the holding system 32 is also configured to give the closing part 27 only one degree of freedom in translation in a translation direction D1, which is for example perpendicular to the junction zone and therefore parallel to the axis of rotation A, when the closing part 27 is moved between the intermediate position and the closing position. For this purpose, the holding system 32 comprises a first guide member 39, such as a hollow guide member, and a second guide member 41, such as a projecting guide member, secured respectively to the mixing part 6 and to the closing part 27 and configured to be mounted sliding one inside the other in the translation direction D1.

[0139] The first and second guide members 39, 41 have complementary and non-circular cross-sections, and are configured to guide the closure portion 27 in translation relative to the mixing portion 6 and in the translation direction D1 when the closure portion 27 is moved between the intermediate position and the closed position. According to the embodiment shown in the figures, the first guide member 39 delimits the passage opening 29 provided on the mixing body 7, and the second guide member 41 projects downwards from a lower face of the closure portion 27 and is configured to be introduced into the passage opening 29. However, according to an alternative embodiment of the invention, the first and second guide members 39, 41 could be offset laterally relative to the filling opening 28 and the passage opening 29.

[0140] As shown more particularly in [Fig. 17], the closing part 27 further comprises an air supply duct 42 connected to the main flow duct 15 via the air intake channel 23, and an air flow adjustment device 43 configured to adjust a flow rate of air flowing in the air supply duct 42. However, according to an alternative embodiment of the invention, the mixing part 6 could be devoid of the air intake channel 23, and the air supply duct 42 could be connected directly to the main flow duct 15.

[0141] According to the embodiment shown in the figures, the air flow adjustment device 43 comprises a support part 44 fixed to the closure part 27 and projecting from an upper face of the closure part 27, and a flow adjustment member 45, such as a flow adjustment knob, supported by the support part 44 and mounted movably, and for example mounted movably in a helical movement, relative to the support part 44 in a direction of movement D2 which may for example be substantially vertical when the milk frothing device 2 rests on a horizontal surface.

[0142] The flow rate adjustment member 45 and the support part 44 may for example extend coaxially with respect to each other, and the support part 44 may for example comprise two guide fingers 46 (see in particular [Fig. 14]) diametrically opposed and slidably mounted respectively in two helical guide grooves 47 provided on the flow rate adjustment member 45.

[0143] According to the embodiment shown in the figures, the flow rate adjustment member 45 comprises an adjustment part 45.1 which is configured to cover the support part 44 and which comprises an upper wall covering the support part 44 and a peripheral wall having a generally tubular shape and extending around the support part 44. As shown more particularly in [Fig.l], the flow rate adjustment member 45 further comprises a manipulation part 45.2 secured to the adjustment part 45.1 and configured to be manipulated by a user so as to move the flow rate adjustment member 45 in the direction of movement D2.

[0144] The flow rate adjustment member 45 is configured to occupy a plurality of adjustment positions offset from each other in the direction of movement D2. Advantageously, the direction of movement D2 is substantially parallel to the central axis of the milk tank 4 when the mixing portion 6 is received in the milk tank 4 and the closing portion 27 is in the closed position.

[0145] The air flow adjustment device 43 further comprises a sealing element 48 which is annular and which is fixed to the flow adjustment member 45. According to the embodiment shown in the figures, the support part 44 comprises a bearing surface 49, provided on an upper end face of the support part 44, which is annular and against which the sealing element 48 is capable of being compressed depending on the position occupied by the flow adjustment member 45.

[0146] The sealing element 48 and the support portion 44 are configured to delimit an air flow passage 51 (see [Fig. 16]) having a passage section which varies depending on the position occupied by the flow rate adjustment member 45. The air flow passage 51 is more particularly configured to fluidically connect an air intake opening 52, defined by the air flow adjustment device 43, to the air supply duct 42. According to the embodiment shown in the figures, the air intake opening 52 is defined by a functional clearance between the flow rate adjustment member 45 and the support portion 44.

[0147] The flow rate adjustment member 45 is more particularly movable between a maximum adjustment position in which the passage section of the air flow passage 51 is maximum, and a minimum adjustment position in which the passage section of the air flow passage 51 is minimal, and for example zero or substantially zero.

[0148] As shown in [Fig. 15], the support portion 44 comprises a recess 53 which is formed in the bearing surface 49 and which partly delimits the air flow passage 51. The recess 53 may for example extend radially relative to the direction of movement D2, and have a generally V-shaped cross-section.

[0149] As shown more particularly in [Fig. 17], the air supply duct 42 comprises a calibrated air passage 54 which is located downstream of the flow adjustment member 45 and which is configured to define a maximum air flow in the air supply duct 42.

[0150] According to the embodiment shown in the figures, the support portion 44 comprises an insertion hole 55, which may for example have a diameter greater than one millimeter and preferably greater than 1.5 millimeters, oriented substantially parallel to the direction of movement D2, and the air flow adjustment device 43 comprises a passage restriction member 56, such as a pin or a needle of generally cylindrical shape, having a lower end portion which is housed in the insertion hole 55. The passage restriction member 56 is integral in movement with the flow adjustment member 45, and is therefore mounted movably in the insertion hole 55 in the direction of movement D2. The passage restriction member 56 is elongated and extends in an extension direction which is parallel to the direction of movement D2.The insertion hole 55 and the passage restriction member 56 more particularly delimit the calibrated air passage 54, such that the calibrated air passage 54 is annular.

[0151] According to the embodiment shown in the figures, the support part 44 comprises a cavity 57 which opens into the upper end face of the support part 44 and into which the insertion hole 55 opens. The cavity 57 and the flow adjustment member 45 delimit an internal chamber 58 configured to fluidically connect the air flow passage 51 to the insertion hole 55.

[0152] Of course, the present invention is in no way limited to the embodiment described and illustrated which has been given only as an example. Modifications remain possible, in particular from the point of view of the constitution of the various elements or by substitution of technical equivalents, without departing from the scope of protection of the invention.

Claims

Claims

1. A milk frothing device (2) for cooperating with an automatic coffee machine (3), the milk frothing device (2) comprising: - a mixing portion (6) comprising a mixing chamber (13) provided with an outlet (14), a hot water / steam inlet (21) and a main flow conduit (15) connecting the hot water / steam inlet (21) to the mixing chamber (13), - a closing portion (27) movable relative to the mixing portion (6) between a closing position in which the closing portion (27) closes the mixing chamber (13) and the main flow conduit (15) and an opening position in which the mixing chamber (13) and the main flow conduit (15) are open and accessible for cleaning, - a milk supply conduit (22) connected to the main flow conduit (15), - an air supply duct (42) connected to the main flow duct (15),and - a seal (25) arranged at a junction zone between the mixing part (6) and the closing part (27) and extending around the mixing chamber (13) and the main flow duct (15), characterized in that the air supply duct (42) comprises a calibrated air passage (54) configured to define a maximum air flow rate in the air supply duct (42) which is independent of the seal (25).,

2. A milk frothing device (2) according to claim 1, which comprises an air flow rate adjustment device (43) configured to adjust a flow rate of air flowing in the air supply duct (42).

3. Milk frothing device (2) according to claim 2, wherein the calibrated air passage (54) is located downstream of the air flow adjustment device (43).

4. Milk frothing device (2) according to claim 2 or 3, wherein the air flow adjustment device (43) comprises: - a flow adjustment member (45) mounted to move in a direction of movement (D2) and configured to occupy a plurality of adjustment positions offset from each other according to the direction of movement (D2), and - a sealing element (48) partially delimiting an air flow passage (51) having a passage section which varies according to the position occupied by the flow adjustment member (45).

5. A milk frothing device (2) according to claim 4, wherein the air flow adjustment device (43) comprises at least one air intake opening (52), the air flow passage (51) being configured to fluidly connect the at least one air intake opening (52) to the calibrated air passage (54).

6. A milk frothing device (2) according to claim 4 or 5, wherein the air flow adjustment device (43) comprises a support portion (44) attached to the closure portion (27) and configured to support the flow adjustment member (45), the flow adjustment member (45) being mounted movably relative to the support portion (44).

7. A milk frothing device (2) according to claim 6, wherein the support portion (44) comprises an insertion hole (55), and the air flow adjustment device (43) further comprises a passage restriction member (56) housed at least partly in the insertion hole (55), the insertion hole (55) and the passage restriction member (56) delimiting the calibrated air passage (54).

8. A milk frothing device (2) according to any one of claims 1 to 7, wherein the closure portion (27) comprises the air supply duct (42).

9. A milk frothing device (2) according to any one of claims 1 to 8, wherein the joining area is planar.

10. A milk frothing device (2) according to any one of claims 1 to 9, wherein the mixing portion (6) comprises the milk supply conduit (22).

11. A milk frothing device (2) according to any one of claims 1 to 10, wherein the milk supply conduit (22) comprises a calibrated flow passage (22.2) configured to define a predetermined milk flow rate in the milk supply conduit (22).

12. Milk frothing device (2) according to any one of claims 1 to 11, wherein the main flow conduit (15) comprises a section restriction (16) forming a milk and air suction system based on the venturi effect.

13. Milk frothing device (2) according to any one of claims 1 to 12, wherein the seal (25) has a constant section.

14. A milk frothing device (2) according to any one of claims 1 to 13, wherein the mixing chamber (13) is of the cyclonic type and extends vertically, the main flow conduit (15) opening into an upper part of the mixing chamber (13) and the outlet orifice (14) being located in a lower part of the mixing chamber (13).

15. A milk frothing device (2) according to any one of claims 1 to 14, which comprises a milk reservoir (4) comprising an upper opening (5), the mixing portion (6) being arranged at the upper opening (5).

16. A milk frothing device (2) according to claim 15, wherein the mixing portion (6) and the closing portion (27) are configured to close the milk reservoir (4) and to be removable from the milk reservoir (4).

17. Milk frothing device (2) according to any one of claims 1 to 16, which comprises a holding system (32) configured to hold the closing part (27) in the closed position.

18. Milk frothing device (2) according to claim 17, wherein the holding system (32) is configured to ensure compression of the seal (25) when the closing portion (27) is in the closed position.

19. An automatic coffee machine (3) comprising a hot water / steam outlet nozzle, a boiler producing hot water and / or steam to supply said hot water / steam outlet nozzle, and a milk frothing device (2) according to any one of claims 1 to 18, the hot water / steam inlet (21) of the milk frothing device (2) being connected to the hot water / steam outlet nozzle.

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