Patent Description:
It is well known that coffee made from freshly ground beans gives better quality than pre-ground coffee. Often, fresh beans are used when making espresso coffee.

There are many different types of commercially available espresso coffee machine, for use in the home, or in bars, restaurants and hotels. The type of machine which is appropriate in a particular setting for example depends on the amount of use, and the budget.

In a manual espresso machine, a user fills a coffee receiving vessel, known as a portafilter, with coffee grounds. The user then needs to tamp the coffee grounds within the portafilter with sufficient pressure, such as around 200N, to create a so-called puck. The portafilter is then mounted to the coffee machine, usually via a bayonet type of connection. Next, the coffee machine drives hot water through the puck in the portafilter and the resulting coffee is dispensed via a spout that is typically integrated in the portafilter. After brewing, the user needs to disconnect and empty the portafilter, throwing away the used coffee grounds.

In a bar setting, the manual process is conducted by a barista. In a domestic setting, the manual steps of the process may make the user feel more involved in the coffee making process, and hence may give the feeling of performing the role of a barista.

There are also manual espresso machines with an integrated grinder. A user switches the portafilter between a first position where it receives ground coffee and a second position where coffee is brewed. Tamping may be done manually or via a manually operated lever.

In a fully automatic espresso machine, all of the above-mentioned steps are done automatically, in one and the same machine. The machine comprises a bean reservoir and a grinder, to make the coffee grounds. These grounds are transported into a brew chamber and tamped automatically, via a piston that may be hydraulically actuated or actuated via an electromotor. Next, hot water is driven through the coffee grounds in the brew chamber, coffee is brewed and dispensed, and the used coffee grounds are discharged from the brew chamber into a waste bin within the machine.

This removes the manual steps required by a manual espresso machine and hence saves time, as well as ensures more uniform results.

A manual espresso machine can be produced at lower cost than a fully automatic espresso machine, since many of the transporting steps do not need to be automated. However, the results may be less uniform, as a result of the user involvement in the filling and tamping process, in particular the user involvement in setting the volume or weight of coffee grounds, and the force and uniformity (straightness) of tamping of the coffee grounds into a puck. A manual espresso machine needs less maintenance since the coffee puck is removed after every brew by the consumer as part of the brewing process.

A fully automatic machine gives more consistent results, but is more costly. It also removes the barista feel of using a manual espresso machine. The fully automatic coffee machine also needs more maintenance (filling of coffee beans, water filing, removing waste water and getting rid of the coffee waste in the waste bin). The fully automatic coffee machine may also be bigger.

A third type of coffee machine has been proposed, which combines elements from the two types described above. This is described in this document as a hybrid espresso machine.

For example, <CIT> discloses a coffee machine with a removable portafilter as used in a manual espresso machine, but which also includes a bean reservoir and a coffee mill for delivering coffee powder to an inserted portafilter. The portafilter functions as the brewing chamber, and a distribution filter (forming a plunger) is used for automatically tamping and thereby compacting the coffee powder in the portafilter before pressurized hot water is delivered to the portafilter through that distribution filter.

This hybrid espresso machine thus combines elements from a manual espresso machine and a fully automatic espresso machine. In this type of machine, the user thus only needs to connect the empty portafilter to the machine. The grinding, dosing of the ground coffee in the portafilter, tamping of the ground coffee, hot water delivery and coffee dispensing is then automated as in a fully automatic machine. After brewing, the user needs to disconnect the portafilter and discharge the coffee waste, similarly to the way a manual espresso machine is used.

This invention relates generally to this hybrid type of espresso or coffee machine, namely with an external portafilter but with closing of the portafilter and tamping (if desired) implemented by the coffee machine, to give consistent results.

In the existing proposed designs, the provision of the water supply through the plunger, via the distribution filter, complicates the hydraulic connections in that a movable fluid connection is needed to the distribution filter, as it moves with the plunger.

Furthermore, the distribution filter requires thorough cleaning because it has a number of holes which can become clogged with stuck coffee particles.

Examples in accordance with an aspect of the invention provide a coffee machine, according to claim <NUM>.

This coffee machine provides the heated water directly to the coffee vessel (which creates the brew chamber, and hence functions as a portafilter) rather than via a distribution head which moves down over the coffee vessel. In this way, a more compact water delivery system is made possible with fewer moving fluid channels.

By removing the water distribution function from the closing and/or tamping system, it can have a smooth surface (instead of an array of distribution holes) which will stay clean, thereby reducing the cleaning effort of the user and limiting the amount of stale old coffee particles in the brewing area.

The coffee vessel is preferably for removable fitting to the exterior mounting port by a bayonet fitting. This is a well-known coupling design for attaching a coffee vessel, e.g. portafilter, to a coffee machine.

The main housing may comprise a water delivery port for delivering heated water to the coffee vessel, and the water delivery port is brought into fluid connection with the water entry port (of the coffee vessel) when the coffee vessel is fitted to the exterior mounting port.

Thus, the fitting of the coffee vessel, e.g. portafilter, automatically implements the required fluid connections to allow heated water to flow to the coffee vessel.

The closing and/or tamping system comprises a tamping piston.

The tamping piston may have an annular groove which communicates with the water entry port. The groove serves to distribute water around the coffee vessel and thus performs the function of a distribution head. The water entry port may then comprise a single opening at an inner face of the side wall. Thus, the water entry port may be a simple channel passing through the side wall of the coffee vessel. The annular groove in the tamping piston distributes the water.

There may instead be an annular groove around the inside of the coffee vessel (below the maximum insertion depth of the tamping piston).

In another design, the water entry port comprises a set of openings at an inner face of the side wall. In this way, a distributed arrangement of openings may be provided by a channel arrangement within the body of the coffee vessel.

The coffee machine for example comprises a hydraulic actuator, wherein the closing and/or tamping system is driven by the hydraulic actuator. The hydraulic actuator is for example for displacing the closing and/or tamping system up and down. Thus, the coffee vessel remains static which simplifies the fluid connections to the coffee vessel. Rigid fluid couplings may be used which engage with each other when the coffee vessel is attached to the coffee machine.

The closing and/or tamping system is for example actuatable between an upper position and a lower position, wherein the coffee machine comprises a chute for delivering coffee grounds to the coffee vessel via a space between the closing and/or tamping system and the coffee vessel when the closing and/or tamping system is in the upper position.

Thus, the coffee may be delivered to the coffee machine with the coffee vessel in place, thereby reducing the number of steps for the user. A coffee grinder may be provided for delivering coffee grinds to the chute. A bean reservoir may also be provided for delivering coffee beans to the coffee grinder.

The coffee machine for example comprises a controller, which is adapted to control at least one of:.

The invention provides a coffee machine having an externally fitted coffee vessel (e.g. portafilter) for receiving freshly ground coffee. A closing and/or tamping system is provided for closing the coffee vessel and/or compacting ground coffee in the coffee vessel by providing relative movement between the closing and/or tamping system, and the coffee vessel. The coffee vessel has a water entry port extending through a side wall for delivering heated water to the internal volume of the coffee vessel.

<FIG> shows the general design of a coffee machine to which the invention may be applied. The invention relates in particular to a hybrid espresso coffee machine as explained above.

The coffee machine <NUM> comprises a main housing <NUM> having an exterior mounting port <NUM>, for receiving a coffee vessel <NUM>. The illustrated machine further comprises a steam nozzle <NUM>.

The coffee vessel <NUM> may comprise a filter or filter basket <NUM> (see <FIG> and <FIG>). It may further include a support <NUM>, for accommodating the filter or filter basket. The coffee vessel <NUM> may further comprise a lower spout <NUM> for dispensing brewed coffee, and there may be a crema valve in line with that lower spout. The coffee vessel has a handle <NUM> for assisting the attachment to the mounting port <NUM>. The coffee vessel <NUM> may thus correspond to a conventional portafilter, as illustrated in the Figures. In use, the coffee vessel <NUM> is fitted to the exterior mounting port <NUM>, for example via a bayonet type coupling.

The term "coffee vessel" in this description is used generally to denote a container which is filled with ground coffee and is subsequently closed to form a brew chamber in which the coffee is brewed.

In this hybrid type machine, the brew chamber may be considered to be at least partly external, because it is formed by an external, removable part. However, the ground coffee is delivered internally to the brew chamber. Discharging of the puck after brewing is performed externally, by a user.

The main housing <NUM> contains a hydraulic circuit which provides fluid couplings between a water supply (typically a water reservoir), an internal water heater and a water delivery system having a water delivery head for delivering heated water to the coffee vessel <NUM> (functioning as a brew chamber).

<FIG> shows an example of a possible hydraulic circuit. <FIG> shows an example of a hydraulic circuit with an internal grinder but an external coffee vessel, and thus is suitable for use in a hybrid type coffee machine.

It is noted that <FIG> is adapted from <CIT> to which reference is made for further details. In particular, alternative hydraulic circuits are disclosed in <CIT> which may similarly be adapted, and which are only briefly summarized below.

<FIG> shows a water reservoir <NUM>, a flow meter <NUM> (for flow rate and dosing control), a water heater <NUM>, a water pump <NUM> and a controller <NUM>. The flow meter <NUM> may provide a flow measurement to controller <NUM>, and the controller <NUM> may control the heater and pump to perform the coffee brewing process. The water heater may for instance be a flow through heater, e.g. a thermoblock. The flow meter <NUM> is optional. Dosing and flow rate control may alternatively be done via suitable control of the pump <NUM> (e.g. power level and pump time).

As will become clear from the description below, the coffee machine of the invention provides a fluid passage for delivering heated water directly to the coffee vessel rather than to a water delivery head forming part of the tamping system, as has previously been proposed and as is disclosed in document <CIT>. In the known design, a water delivery head is used which comprises a water distribution disc. The water distribution disc provides an area of water delivery to the ground coffee.

A closing and tamping system is provided for compacting the ground coffee in the coffee vessel by providing relative movement between a tamping piston <NUM> and the coffee vessel <NUM>. This relative displacement closes the coffee vessel to form a closed chamber, i.e. a brew chamber. It furthermore applies force to the ground coffee to perform tamping. The relative movement is achieved by moving the tamping piston <NUM>.

The closing and tamping system includes a hydraulic actuator <NUM>, comprising the piston <NUM> which is driven by hydraulic pressure. The hydraulic actuator may further comprise a return spring (not shown), to help retracting the piston after brewing.

A water outlet from the water pump <NUM> is coupled, via the heater <NUM>, to the hydraulic actuator <NUM> by a first fluid coupling <NUM>. The water outlet from the water pump is also coupled to the coffee vessel by a second fluid coupling <NUM>. The second fluid coupling <NUM> includes a passive in-line valve <NUM>. The passive in-line valve opens when the pressure at the inlet side of the hydraulic actuator (i.e. at branch point <NUM>) reaches a desired pressure, e.g. a desired tamping pressure.

Below this pressure, the valve <NUM> stays closed. There may be hysteresis, so that the valve <NUM> opens at a first threshold pressure (an opening pressure), but only recloses when a lower second threshold pressure (a closing pressure) is reached. Alternatively, there may be only one threshold pressure.

In this way, the water pump <NUM> is used for both water delivery for brewing as well as water delivery for closing and tamping. The passive in-line valve <NUM> switches automatically between these two water delivery functions, without the need for user interaction or electrical actuators. The passive valve <NUM> opens for instance when a tamping pressure has been reached, i.e. when tamping has been completed. Water delivery then takes place to the coffee vessel via the open valve <NUM>. During this water delivery to the coffee vessel, the tamping pressure is maintained.

In cases where no tamping of the coffee grounds is desired, the same system may be used to merely close the coffee vessel <NUM>. In such case, the passive in-line valve <NUM> may open when a closing pressure has been reached.

It is also conceivable that closing of the coffee vessel is done via a different mechanism, e.g. manually. In such case, aforementioned system may be used to merely tamp the coffee grounds. The passive in-line valve <NUM> may then again open when a suitable tamping pressure has been reached, i.e. when tamping has been completed.

The passive valve <NUM> functions as a pressure controlled system in that it responds to the prevailing pressure. Thus, the closing and/or tamping is reliable and repeatable. By implementing pressure control, the desired closing and/or tamping pressure may be applied to any volume of coffee within the coffee vessel, which is not simple to achieve if position control is employed.

To drain water from the hydraulic actuator, a return path may be provided between the hydraulic actuator <NUM> and the water reservoir <NUM>, as shown in <FIG>. To open or close the return path, a valve <NUM> may be provided. The valve <NUM> may for instance comprise an electronic shut-off valve. However, a lower cost alternative is a mechanical lock that may be actuated either by a separate handle, or by the action of attaching/ detaching the coffee vessel <NUM>. More particularly, the valve <NUM> may be closed when the coffee vessel <NUM> is attached and opened when the coffee vessel is detached. Thus, opening and closing of the valve <NUM> may be controlled in response to or through a user attaching/detaching the coffee vessel.

In the example shown in <FIG>, the first and second fluid couplings <NUM>, <NUM> meet at the branch point <NUM> downstream of the heater <NUM>. Water is routed from the same branch point <NUM> either to the hydraulic actuator <NUM> or to the coffee vessel. To avoid the use of hot water for the closing and/or tamping process, the controller <NUM> may switch off the water heater <NUM> during actuation of the hydraulic actuator <NUM> and switch on the water heater during water delivery to the coffee vessel.

In a first possible modification to the hydraulic circuit of <FIG>, the first fluid coupling <NUM> may instead be between the water reservoir <NUM> (or more particularly, the water pump <NUM>) and the hydraulic actuator <NUM> without passing the water heater <NUM>, since hot water is not needed for driving the hydraulic actuator <NUM>. The second fluid coupling <NUM> is however between the water reservoir <NUM> (or more particularly, the water pump <NUM>) and the coffee vessel passing the water heater <NUM>.

In a second possible modification to the hydraulic circuit of <FIG>, the first fluid coupling <NUM> may instead be between the water reservoir <NUM> and the hydraulic actuator <NUM> without passing the water heater <NUM>, and includes the pump <NUM>. The second fluid coupling <NUM> is then between the hydraulic actuator <NUM> and the coffee vessel and passes the water heater <NUM>. Thus, the two fluid couplings are in series, with one on each side of the hydraulic actuator <NUM>. The pump <NUM> is in the first fluid coupling <NUM> and the heater <NUM> is in the second fluid coupling <NUM>. Cold water may again be used for closing and/or tamping and hot water may be used for brewing. The heating takes place between the hydraulic actuator and the coffee vessel. This avoids cooling of the water during the closing and/or tamping process and reduces energy usage.

More details of these alternatives are in document <CIT>. Furthermore, the invention is not limited to this use of a passive in-line valve, and more conventional hydraulic circuits may be used with active valves separating the different flow paths in the system.

<FIG> also show a bean reservoir <NUM> and a coffee grinder <NUM> having a ground coffee outlet <NUM>. <FIG> thus shows an internal coffee grinder and a brew chamber in the form of a coffee vessel <NUM> which is removably mounted to an external mounting port <NUM> and is emptied externally by the user as part of the normal operation of the coffee machine.

<FIG> shows an example of the coffee vessel <NUM> used in the hydraulic circuit described above, in accordance with the invention. As described above, the coffee vessel is for removable fitting to the exterior mounting port and is adapted to receive freshly ground coffee.

The coffee vessel <NUM> comprises a base <NUM> and a side wall <NUM> together defining an internal volume <NUM> and an open top <NUM>. The coffee vessel further comprises a water entry port <NUM> extending through the side wall <NUM> for delivering heated water to the internal volume <NUM> of the coffee vessel. In this way, water does not need to be delivered through the tamping piston <NUM>, which can therefore have a smooth end face with no holes. This makes cleaning easier, and the coffee vessel is the part which has to be cleaned thoroughly. This is of course simple because it is removed from the coffee machine at each user and may for example be washed in a dishwasher.

The exterior mounting port has a water delivery port for delivering heated water to the coffee vessel. When the coffee vessel is fitted to the main housing, for example by a bayonet coupling as described above, the water delivery port (of the main housing, and forming part of the bayonet coupling) is brought into fluid connection with the water entry port <NUM>.

Thus, the rotation of the coffee vessel to complete the bayonet coupling brings the water entry port and the water delivery port into alignment. A seal may be retained by the coffee vessel or the main housing, which is compressed when the bayonet coupling is complete.

The water entry port <NUM> has an external connection port <NUM> which couples to the water delivery port, and an internal opening <NUM> which leads to the internal volume <NUM>.

In the example shown in <FIG>, the water entry port <NUM> has a single internal opening <NUM> at an inner face of the side wall <NUM> and a single connection port <NUM> at an outer face of the side wall.

However, as shown further below, the tamping piston may have an annular groove which communicates with the water entry port <NUM>, in particular the internal opening <NUM>, so that the water is spread around an annulus.

As an alternative, the water entry port <NUM> may comprise a set of openings at the inner face of the side wall but a single connection port at an outer face of the side wall. Thus, internally within the body of the coffee vessel, the single connection port at the outside of the coffee vessel may then branch into a set of internal openings to provide a more uniform delivery of water to the internal volume <NUM>.

<FIG> shows the coffee vessel <NUM> with the closing and/or tamping system, in particular a tamping piston <NUM> having a lower closing face <NUM> spaced above the open top of the coffee vessel.

<FIG> shows an upper position of the tamping piston <NUM>. The coffee machine comprises a chute <NUM> (as mentioned above) for delivering coffee grounds to the coffee vessel via the space between the lower closing face <NUM> and the coffee vessel, when in this upper position. The delivery of coffee grounds is represented by arrow <NUM>. The chute <NUM> receives coffee from the coffee grinder <NUM>, which in turn receives coffee beams from the bean reservoir <NUM>. However, pre-ground coffee may instead be provided either via the chute or directly into the coffee vessel.

<FIG> also shows the annular groove <NUM> around the bottom of the tamping piston <NUM>. A crema valve <NUM> is at the outlet from the coffee vessel, through which brewed coffee is delivered.

The coffee dosing starts when the coffee vessel is attached to the main housing.

The closing and optionally also tamping then takes place as shown in <FIG>. The tamping piston <NUM> is moved to a lower position in which it closes the open top of the coffee vessel and if desired compacts the coffee grounds. The tamping piston thus moves down to tamp the coffee bed and form a watertight brewing chamber with the internal volume <NUM> of the coffee vessel.

The water used to brew the coffee is fed into and through the side wall of the coffee vessel. The water connection to the water entry port <NUM> is connected to the water supply of the coffee machine by the same movement that is used to lock the coffee vessel to the appliance.

In the example shown, the water is spread around the circumference of the coffee vessel by the annular groove <NUM> in the tamping piston <NUM>. As explained above, water could also be injected from one or more internal openings in the side wall.

The example above makes use of a hydraulically actuated tamping piston. However, an electric actuator may be used or even a manual lever.

Different channel designs may be provided at the base of the tamping piston or around the side wall of the coffee vessel to provide a distribution function. However, in all cases the water is delivered to the internal volume <NUM> through a side wall of the coffee vessel rather than through the body of the tamping piston.

Claim 1:
A coffee machine, comprising:
a main housing (<NUM>) having an exterior mounting port (<NUM>);
a water reservoir (<NUM>);
a water heater (<NUM>);
a water pump (<NUM>);
a coffee vessel (<NUM>) for removable fitting to the exterior mounting port and adapted to receive freshly ground coffee;
a closing and/or tamping system (<NUM>) comprising a tamping piston, the closing and/or tamping system (<NUM>) for closing the coffee vessel and/or compacting ground coffee in the coffee vessel by providing relative movement between the closing and/or tamping system and the coffee vessel;
wherein the coffee vessel comprises a base (<NUM>) and a side wall (<NUM>) defining an internal volume (<NUM>) and an open top (<NUM>), the coffee machine being characterized in that J Z the coffee vessel comprises a water entry port (<NUM>) extending through the side wall for delivering heated water to the internal volume (<NUM>) of the coffee vessel.