U.S. patent application number 10/981978 was filed with the patent office on 2005-06-02 for automatic device for heating and frothing a liquid, in particular milk.
Invention is credited to Bottelli, Eliano, Oldani, Renzo.
Application Number | 20050115419 10/981978 |
Document ID | / |
Family ID | 11457847 |
Filed Date | 2005-06-02 |
United States Patent
Application |
20050115419 |
Kind Code |
A1 |
Oldani, Renzo ; et
al. |
June 2, 2005 |
Automatic device for heating and frothing a liquid, in particular
milk
Abstract
An automatic device for heating and frothing a liquid, in
particular milk, comprises a container for the liquid, inside which
a first tube for introducing pressurised steam into the liquid is
removably mounted. The first tube has an inlet in correspondence of
the bottom of the container, for receiving steam from a duct
located within a support base of the container, and is secured, for
at least part of its length, to a second tube for introducing air
into the liquid.
Inventors: |
Oldani, Renzo; (Villastanza
di Parabiago, IT) ; Bottelli, Eliano; (Villastanza di
Parabiago, IT) |
Correspondence
Address: |
RATNERPRESTIA
P O BOX 980
VALLEY FORGE
PA
19482-0980
US
|
Family ID: |
11457847 |
Appl. No.: |
10/981978 |
Filed: |
November 5, 2004 |
Current U.S.
Class: |
99/453 |
Current CPC
Class: |
A47J 43/125 20130101;
A47J 31/4485 20130101; A47J 36/34 20130101; A47J 31/4489
20130101 |
Class at
Publication: |
099/453 |
International
Class: |
A23C 003/02 |
Foreign Application Data
Date |
Code |
Application Number |
Jun 23, 2000 |
IT |
TO2000A000616 |
Claims
What is claimed:
1. A device for heating and frothing a liquid comprising a
container and a steam tube in a container, one end of said steam
tube being connected to a source of steam, the other end of said
steam tube being located near the bottom of said container and
having an outlet opening by which steam exits the steam tube in a
direction parallel to the bottom of the container, wherein said
container is removably mounted on a base and said base and said
steam source comprise an opening in said base through which steam
is provided to said steam tube.
2. A device, as in claim 1, wherein the tube outlet is located near
the side of the container and the outlet opening causes the steam
to exit the tube in a direction toward the center of the
container.
3. A device, as in claim 1, wherein the container includes a second
tube, the second tube having an inlet open to the atmosphere and
located high enough in the container to be above a preselected
level, said preselected level being above the intended highest
liquid level in the container, the second tube having an opening
located adjacent the exit opening of the steam tube.
4. A device, as in claim 2, wherein the container includes a second
tube, the second tube having an inlet open to the atmosphere and
located high enough in the container to be above a preselected
level, said preselected level being above the intended highest
liquid level in the container, the second tube having an opening
located adjacent the exit opening of the steam tube.
Description
[0001] This application is a divisional application of U.S. patent
application Ser. No. 10/312,367, filed Jul. 9, 2003, which is the
U.S. National Phase of international application No.
PCT/EP01/06966, filed Jun. 19, 201, and claims priority of Italian
application No. T02000A000616, filed Jun. 23, 2000.
FIELD OF THE INVENTION
[0002] The present invention concerns an automatic device for
heating and frothing a liquid, in particular milk.
BACKGROUND OF THE INVENTION
[0003] Preferably, the invention is applied in espresso coffee
machines for bars, for producing frothy hot milk to be used e. g.
in preparing cappuccinos, and the following description will refer
to such a preferred application.
[0004] It is known that, in order to produce milk froth by means of
espresso coffee machines, the operator utilises a container into
which he pours a certain quantity of milk; then he introduces steam
into the milk by a nozzle while stirring the container, so as to
create a certain turbulence in the milk and incorporate the ambient
air necessary to form the froth.
[0005] The characteristics and the quantity of the froth produced
depend on the modalities of milk stirring and steam introduction,
and therefore on the sensitivity and the skill of each
operator.
[0006] Thus, such characteristics, and therefore the
characteristics of the cappuccino in which the frothy milk is used,
change from one operator to another and may be wholly
unsatisfactory for the client, even if the operator judges them
optimal.
[0007] Moreover, with the present technique problems may arise also
from the hygienic standpoint, due in particular to the presence of
milk crusts on the nozzle tip that are produced by successive
frothing operations and that can remain exposed to air for a
certain time.
SUMMARY OF THE INVENTION
[0008] A solution of the problems related to the dependency of the
product quality on the individual operator is the subject matter of
French patent application No. 2,604,077. That application discloses
a device in which the steam nozzle is secured to an air feed duct,
which has a bottom axial opening for air outlet arranged in front
of the steam outlet opening of the nozzle, so that the steam licks
the air jet and generates the required turbulence. Such a solution
requires, for a proper operation, the presence of a chamber for
mixing air and steam before introducing them into the liquid, and
this makes the structure rather complex. Moreover, it leaves the
problems of hygienic nature unsolved.
[0009] GB 382 972 discloses an apparatus for making what is known
in the culinary art as whipped cream. This apparatus comprises a
tank having close to its bottom a block of material porous to air.
Between the block and the bottom of the tank a pressure chamber is
defined where compressed air is admitted. Whipped cream is produced
by forcing air in an ascending direction into the tank through the
bottom block which is preferably made of porous stone.
[0010] EP 0287906 refers to an apparatus for heating and
emulsifying liquids, in particular milk, contained in a tank,
comprising a tube to be immersed in the liquid in the container,
said tube being opened at its upper end for coupling the tube to a
source of steam and at its lower end for expelling the steam into
the liquid. According to this invention the tube comprises a radial
calibrated orifice close to its upper end so as to obtain a level
inside the tube equal to the external level.
[0011] FR 0775618 and FR 0769848 disclose an apparatus for mixing
air into a liquid for the purpose of preparing cream through a
separating porous plate provided close to the bottom of a tank and
defining a chamber for pressurized air between said plate and the
bottom of the tank.
[0012] U.S. Pat. No. 5,335,588 refers to an apparatus for milk
frothing comprising a first pipe for admitting steam into the milk
through its bottom open end and a second pipe for creating a
venturi effect and improving the quantity of air mixed with the
milk.
[0013] DE 29721055U refers to an arrangement for holding a pail on
a stove during cooking having a pair of vertical arms which hold
the pail firmly in position.
[0014] The aim of the invention is to provide an automatic heating
and frothing device, which allows producing a froth with
substantially constant characteristics, is of simple structure and
does not give rise to the above mentioned hygienic problems.
[0015] The characteristics of the invention will become apparent
from the appended claims.
[0016] A device comprising a container for the liquid having a
bottom to which there are connected means for introducing
pressurised steam into the liquid, according to the
non-characterising clause of claim 1, is disclosed in Utility Model
Application No. TO 2000 U 000076.
[0017] For a better understanding, reference is made to the
accompanying drawings, which show a preferred embodiment of the
invention, given by way of non limiting example, and in which:
BRIEF DESCRIPTION OF THE DRAWINGS
[0018] FIG. 1 is a side view of the device according to a first
embodiment of the invention;
[0019] FIGS. 2 and 3 are perspective top and bottom views,
respectively, of the milk container of the embodiment shown in FIG.
1;
[0020] FIG. 4 show the steam and air ducts removed from the
container;
[0021] FIG. 5 is an enlarged view of a detail of FIG. 4;
[0022] FIG. 6 is a perspective view of the support base for the
container shown in FIG. 3;
[0023] FIG. 7 is a perspective view of a second embodiment of the
invention;
[0024] FIG. 8 is a perspective view similar to FIG. 7, showing the
container secured to the base;
[0025] FIG. 9 is a perspective view of the base used in the second
embodiment of the invention; and
[0026] FIG. 10 is a perspective view from the bottom of the
container used in the second embodiment of the invention.
DETAILED DESCRIPTION OF THE INVENTION
[0027] As shown in FIG. 1, the device essentially comprises a
container 1 with a handle 2, mounted on a base 3. The base can be
connected to the source of pressurised steam provided in a
conventional espresso coffee machine (not shown) or it is
internally equipped with an own pressurised steam source,
independent of the source of the coffee machine. Base 3 further is
equipped with an on/off switch 4 and a timer, operated through a
control knob 5 and controlling the opening of an electric valve in
a duct, internal to base 3 and not shown in the drawing, delivering
steam to the container.
[0028] For sake of simplicity, the drawing shows neither the means
for electric power supply of the device, nor the connections, if
any, with the espresso coffee machine, nor the water feed/discharge
ducts for the internal steam source, if any.
[0029] Referring to FIGS. 2 and 3, a first tube 6, intended to
introduce into the milk the steam supplied through the duct
internal to base 3 (FIG. 1), is removably mounted on the bottom of
container 1, inside the container itself. Such a tube 6 is secured
to a second tube 7 intended to introduce the air required to
produce the froth.
[0030] Tube 6 is secured onto the internal side of the bottom of
container 1 by means of a threaded member 8, e. g. welded onto the
bottom of container 1, which is engaged by a complementary member 9
arranged on tube 6 near the lower end thereof. Member 8 has an
axial through-hole 10 (FIG. 3) intended to receive the end portion
of tube 6 and to allow communication between the tube and said duct
internal to base 3. Member 8 outward projects from the bottom of
container 1 to allow a tight engagement, through a seal ring 11, in
a cavity 12 (shown in FIG. 6) of the upper surface of base 3. The
steam feed duct internal to base 3 has an outlet 13 opening in
correspondence with the bottom of said cavity.
[0031] Moreover, for securing container 1 to base 3, the bottom of
container 1 is externally equipped with a set of tongues 14
arranged to engage corresponding openings 15 in the upper face of
base 3 and to be retained, upon a rotation of container 1 about its
axis, by plates 16 separating openings 15. Openings 15 and plates
16 adjacent thereto are preferably arranged on an annulus
concentric with cavity 12.
[0032] Turning again to FIG. 2 and referring also to FIGS. 4 and 5,
tube 6 includes: a first portion 60 with axis substantially
parallel with the axis of container 1; an intermediate portion 62,
substantially rectilinear and inclined downwards, connected to the
first portion 60 by a bent section 61; and an end portion 63, also
with substantially vertical axis, ending near the bottom of
container 1. Preferably, the length of intermediate portion 62 is
such that end portion 63 is substantially adjacent with the
internal wall of containers. Tip 64 of such end portion 63 is
closed, but a radial opening 65 for steam outlet is provided near
the tip itself.
[0033] When pouring the frothy milk, such a shape prevents small
quantities of the milk entering tube 6 through opening 65 from
flowing out through opening 10 in the container bottom.
[0034] Air tube 7 is open at both ends and includes two sections
70, 71 arranged substantially parallel with the intermediate and
end portions 62,63, respectively, of steam tube 6. The open end of
section 70 is to lie above the milk level within the container. End
portion 72 of section 71, as better shown in FIG. 5, is tapered or
has anyway a reduced cross-sectional size, so as to give rise to an
air jet, and it ends with an axial opening 73 arranged in front of
opening 65 of tube 6, so as to partly obstruct opening 65.
[0035] The operation of the described device is as follows. Once
the container 1 has been filled with the required milk amount (in
any case, up to a level below the upper opening of tube 7), it is
placed on base 3 so that the outward projecting portion of member 8
engages cavity 12 and tongues 14 enter cavities 15. By rotating
container 1, the engagement of tongues 14 beneath plates 16 is
obtained. Thereafter, the desired heating time is set through timer
5, which opens the electric valve in the duct ending at the bottom
of cavity 12. Thus the steam can pass from the source (inside or
outside the base) to tube 6 and flow out through opening 65
thereof. Given the relative position of steam and air outlets
65,73, steam flowing out of opening 65 originates a vacuum, which
in turn causes air intake through tube 7. The steam outflow speed
thus creates a turbulence on the milk bottom, making the milk
become heated and mix with air supplied through tube 7. Thus a
milk-air-steam mixture is created directly within the milk. When
the time set is over, the electric valve is closed thereby stopping
steam supply and, after rotating container 1 to release tongues 14,
container 1 can be removed from base 3 to pour the frothy milk.
[0036] Referring now to FIGS. 7 to 10, a second embodiment is shown
employing different and more robust means for securing container 1
to base 3. In such Figures, the elements already discussed in
connection with FIGS. 1 to 6 are denoted by the same reference
numerals. The arrangement of tubes 6,7 introducing steam and air
into the milk is the same as in the first embodiment.
[0037] Container 1 has on its external wall a pair of diametrically
opposed projections 20 (of which only one can be seen in the
drawings), arranged to co-operate with a pair of upright retaining
members 21 projecting from the upper surface of base 3. Retaining
members 21 are each made by a bar, with rounded cross-sectional
shape, bent to an inverted U shape. Each projection 20 engages, in
operating conditions of the device, the underside of a horizontal
upper section 21a of a respective retaining member 21, as shown in
FIG. 8. Horizontal section 21a has a central portion slightly
curved in a horizontal plane so as to somewhat conform to the
curvature of the side wall of containers.
[0038] A vertical stem 22 projecting from base 3 carries a control
panel 23 on which on/off switch 4 and control knob 5 for the timer
are mounted. Stem 22 will house the necessary electric wiring for
the switch and the knob.
[0039] As shown in FIG. 9, base 3 is also provided, on its upper
surface, with a number, e.g. four, of freely rotatable ball
supports 24 intended to reduce friction between the bottom of
container 1 and base 3 during the container rotation needed to
bring projections 20 into engagement with retaining members 21.
Ball supports 24 are mounted in elastomeric members 25. One of ball
supports 24 is also arranged to co-operate with a safety switch
(not shown), located within base 3 and intended to cut off power
supply during securing and releasing of container 1.
[0040] Base 3 has a central projection 26 housing end portion 27 of
the steam feed duct located internally of base 3. Projection 26 is
intended to sealingly engage, through a seal ring 28, a cavity 29
(visible in FIG. 10) provided in fastening member 8, so as to
establish communication between end portion 27 of the steam feed
duct and tube 6.
[0041] The operation of that second embodiment is quite similar to
that of the embodiment shown in FIGS. 1 to 6. Once container 1 has
been filled with milk, it will be put on base 3 between retaining
members 21, so that projections 20 lie externally of such members,
as shown in FIG. 7. In doing so, projection 26 engages cavity 29
and outlet opening 13 of end portion 27 of the steam supply duct
comes into alignment with the inlet of tube 6. Container 1 is then
rotated so as to make projections 20 move into the space defined by
the corresponding retaining member 21 and engage the underside of
horizontal sections 21a, as shown in FIG. 8. The cooperation
between projections 20 and horizontal sections 21a will push
downward container 1 against the action of the resilient support
members 25 of ball supports 24. Thus the safety switch is closed.
At the end of the heating time, container 1 will be rotated in the
opposite direction and, as soon projections 20 are no longer
retained by horizontal sections 21a, ball supports 24 will push
upward the container thereby opening the safety switch and cutting
off the power supply. The operations then proceed as already
disclosed for the previous embodiment.
[0042] One can immediately appreciate that the invention allows
solving the problems mentioned in the introduction. Actually, on
the one side the device is automatic, and hence gives a product of
which the quality no longer depends on the skill and/or the
sensitivity of the individual operator; on the other side, the
portions contacting the milk (in particular, steam and air tubes 6
and 7) can be removed from the container and washed immediately
after use, thus avoiding possible pollution.
[0043] It is clear that the above description has been given only
by way of non-limiting example and that changes and modifications
can be made without departing from the scope of the invention. For
instance, the arrangement of switch 4 and control knob 5 shown in
FIG. 7 can be provided also in the embodiment of FIGS. 1 to 6.
[0044] Moreover, even if reference has been made to the preparation
of milk froth and warm milk in espresso coffee machines, the device
can be used to froth and/or heat other liquids, in particularly for
preparing infusions.
* * * * *