Hot milk dispenser

A single unit milk dispenser for producing hot frothed milk or hot non-frothed milk uses milk and steam. A reservoir supplies milk via an adjustable valve to a first chamber. For supplying frothed milk, steam is issued from a first steam outlet nozzle and mixes and froths with the milk in the first chamber and in an expansion chamber before being dispensed out of a collection chamber. For non-frothed milk, steam supplied from a second steam outlet nozzle is released to mix and swirl around with cold milk fed from the reservoir into the collection chamber. The rate of flow of milk out of the reservoir is normally adjusted for the two mode of operation, which mode is simply otherwise determined by which nozzle supplies steam, by turning a steam supply selection knob.

BACKGROUND OF THE INVENTION
 1. Field of the Invention
 The invention relates to hot milk dispensers.
 2. Description of Prior Art
 The invention relates more particularly to dispensing hot milk in a kitchen
 or cafe outlet. It is usual to have such a dispenser for use with and
 often incorporated in a coffee maker, or similar. Typically, this enable
 cappuccino coffee or similar beverages to be mixed up or dispensed at a
 common location.
 It is well-known to prepare frothed milk by flowing steam from a nozzle in
 to a surface of cold milk in a vessel and skilfully moving the vessel up
 and down relative to the end of the nozzle. It is also known to heat up
 milk by immersing and keeping the nozzle below the surface of cold milk to
 prepare hot milk that is not frothed. Non-frothed milk should have no
 foaming at the surface of the milk and be generally hot enough not to
 affect any coffee that it is added to, for example. In any event, although
 the same equipment may be used for producing hot frothed milk or hot
 non-frothed milk, nozzle adjustments, often manually controlled, must be
 made during or for producing one or the other.
 SUMMARY OF THE INVENTION
 It is an object of the invention to overcome or at least reduce this
 problem.
 According to the invention there is provided a single unit milk dispenser
 for producing hot frothed milk and hot non-frothed milk using milk and
 steam, the dispenser comprising a reservoir for containing a supply of
 milk, means for supplying steam under pressure, a first chamber, an
 adjustable valve to allow a flow milk into the first chamber, a first
 aperture in the base of the first chamber, a first steam outlet nozzle
 directed towards the first aperture to blow the milk from the first
 chamber into an expansion chamber where the milk is frothed by the steam,
 a second aperture in the base of the expansion chamber leading to a
 collection chamber for collecting frothed milk that exits from the
 expansion chamber, and a dispensing outlet at the base of the collection
 chamber, a flow passage between the adjustable valve and the expansion
 chamber to allow milk to be supplied from the reservoir into the expansion
 chamber, a second steam outlet nozzle for supplying steam under pressure
 directed across the collection chamber above the dispensing outlet to
 swirl and heat milk passing through the second valve towards the
 dispensing outlet, means for selectively supplying steam either to the
 first steam outlet nozzle for providing hot frothed milk at the dispensing
 outlet or to the second steam outlet nozzle for providing hot-non-frothed
 milk at the dispensing outlet.
 The flow passage preferably comprises the first aperture, the first
 chamber, and the second aperture.
 The second aperture is preferably formed in a raised central part of a
 closure base plate that tends to cause the frothed milk to swirl around
 inside the base of the expansion chamber.
 The second steam outlet nozzle may be mounted next to the first steam
 outlet nozzle and a flow passage provided between the second nozzle and an
 aperture in a side of collection chamber.
 The aperture in the side of the collection chamber is preferably provided
 in a side of a hollow cylinder surrounded by a compartment to allow steam
 and milk to swirl both around in the collection chamber and in the
 compartment.

DESCRIPTION OF THE PREFERRED EMBODIMENTS
 Referring to the drawings, in FIG. 1 a milk reservoir 10 has a restricted
 manually adjustable outlet valve 11. A steam generator 12 supplies steam
 to a selector valve 13 with a rotary manual selector knob 14 that can be
 turned to direct steam, when required, to either outlet pipe 15 or 16. The
 pipes 15 and 16 are connected respectively to supply first and second
 steam outlet nozzles 17 and 18 via flexible hoses 19 and 20.
 An L-shaped milk passage 21 extends from the outlet valve 11 to a small
 aperture 22 in a side of an upper chamber 23 where in use low pressure
 steam from the nozzle 18 mixes with milk fed from the reservoir 10.
 Opposite the nozzle 17 in a base of the chamber 23 is an aperture 24
 leading to a lower frothing chamber 25. A lower exit of the chamber is
 provided by an aperture 26 in a central raised boss of a closure base
 plate 27. The presence of the plate 27 and raised boss tends to cause the
 steam and milk mixture to swirl around in a turbulent manner inside the
 chamber 25 to enhance froth formation. A collection chamber 28 below the
 chamber 25 collects the froth which can be dispensed via a dispensing
 outlet 29.
 Thus, if the knob 14 is moved to a position to select hot frothed milk and
 steam is supplied to the nozzle 17, the dispenser will automatically start
 and continue to provide frothed milk at the outlet 29. It will be noted
 that the valve 11 is also opened to allow milk to be drawn out of the
 reservoir by a partial vacuum created by the flow of steam out of the
 nozzle 17. The dispensing of frothed milk is illustrated in FIG. 3.
 If the knob 14 is moved to a position to select hot non-frothed milk, steam
 will be released into the dispenser via the nozzle 18 into a steam passage
 30. The passage 30 leads to an aperture 31 for directing a stream of low
 pressure steam laterally across the chamber 28 between the aperture 26 and
 the dispensing outlet 29. It will normally be necessarily to open the
 valve 11 when the dispenser is set to produce non-frothed milk. The
 aperture 31 is centrally off-set (as seen in FIG. 2) so that the steam
 tends to swirl with milk flowing slowly out of the nozzle 26 in a
 descending helix. This action also tends to decelerate the normal downward
 flow rate of the milk to provide for more time for the steam to heat the
 milk. This also reduces the degree of formation of foam otherwise caused
 by a fast jet of steam or steam-milk mixture out of the dispensing outlet
 29 into a container, for example a cup placed under the outlet 29. The
 steam also swirls around an outer perimeter of a lower hollow cylindrical
 part of the chamber 30 that is surrounded by an annular compartment 32, as
 can be seen in FIG. 2, to enhance this desired action and mixing.
 Thus, the same or single unit dispenser is capable of producing hot frothed
 milk or hot non-frothed milk (see FIG. 4) simply by selecting either of
 two operating modes, using the rotary knob 14 and normally also adjusting
 the valve 11 to allow milk to flow out of the reservoir at least
 predominately due only to gravity in the non-frothing mode.