GB2642285A - Espresso machine - Google Patents

Abstract

An espresso machine with a support structure that has three or more support elements. The support structure holds a multi-basket portafilter with two or more openings. The multi-basket portafilter rests on the support elements, with at least one support element on either side of each opening. A multi-group head assembly supports piston assemblies that correspond to each of the openings. Each piston assembly has a sealing piston, with a channel for delivery of heated water to portafilter basket, and a gasket. Linear actuators operate to urge the sealing piston into contact with the portafilter basket until the gasket forms a seal between the sealing piston and the portafilter basket. The force applied by the linear actuator may be controlled based on monitoring an electrical current. There may also be sensors that output signals indicating how many portafilter baskets are in use. Each sealing piston may have a heating element and temperature sensor. The espresso machine is capable of preparing multiple coffee shots at once, minimising repetitive strain on users and maximising efficiency over traditional methods.

Description

[0001] Espresso Machine

[0002] Background

[0003] Espresso machines work by passing hot water through finely ground coffee beans at high pressure. The temperature of the hot water can range between 80-96°C.

[0004] Typically, a temperature of above 92°C is used. The hot water is heated using a boiler, a heat exchanger or a thermo-block heater depending on the machine. The boiler typically makes up a large proportion of the rear of a commercial machine. The pressure range of the water can range between 6-12 bar, 9 bar is typical and is generated using an electric pump.

[0005] There are several parameters that influence the taste profile of an espresso shot. The recipe of espresso differs according to the type of coffee beans used and the barista's recipe. Espresso recipes typically state the mass of coffee grounds placed into the portafilter basket, the mass of the final coffee brewed (referred to as "pulling a shot") and the time it takes to brew. For example, 18 g of coffee grounds, 36 g of brewed espresso in a time of 25-30 seconds. The barista can then adjust the ground size of the coffee using the grinder to meet the recipe for the type of coffee beans they are using. Finer grinds tend to increase brew time because the water encounters more resistance to flow, whilst courser grinds will decrease brew time. There are machines in the market that allow the user to adjust numerous other parameters such as flow profiles and pre-infusions pressures, but we will not focus on these in this document.

[0006] Another important area of espresso making is the portafilter preparation. Correct and consistent portafilter preparation is important for the quality of the espresso brewed.

[0007] Portafilter preparation includes emptying and cleaning the previous grounds, dosing the fresh grounds, distributing the grounds, and finally tamping the grounds. The aim of all these steps is to ensure consistent restriction from the coffee puck (compressed grounds). This prevents channels for the water to bypass through the coffee grounds which could result in inconsistent flavour extraction leading to undesirable flavour.

[0008] Temperature control is another important aspect of a good espresso machine. The water needs to be consistently at the required temperature when it flows through the coffee. For this reason, espresso boilers have tuned temperature controllers and temperature probes to ensure the boiler is at the required set temperature and the parts that have hot water passing through them are typically made from brass. The high thermal mass of brass helps maintain a steady surface temperature for the water to flow over with minimal fluctuations. This results in consistent brewing temperatures. It is typical for boiler temperatures to be set to temperatures higher than desired for brewing. This is because there will be an associated heat loss to the environment as the water exits the boiler and travels to the group heads. For this reason, this path is typically insulated or reduced in length as much as possible.

[0009] Boilers are typically set between 90-120°C depending on the machine and the temperature specified by the user. There is usually a temperature off-set variable that can be adjusted. It should be noted that because some boilers may be sealed, water can be heated to 120°C without boiling. At 120°C the vapor pressure of water is approximately 2 Bar therefore the pressure in the boiler would reach this pressure when the water is heated to 120°C.

[0010] Conventional espresso machines that are intended for commercial café use consist of a number of group heads (typically ranging from 1-4) side by side to increase throughput and allow for multiple baristas to pull espresso shots simultaneously. Each group head can accept a single portafilter. The portafilter is typically rotated horizontally into a bayonet thread mechanism by the user. The thread causes the portafilter to screw up into the group head seal. The torque applied by the user forms the seal between the portafilter and the group head. Due to the high temperatures and pressures espresso machines are required to run at, the seal must maintain zero leakage at up to 12 bar and 100°C.

[0011] WO 2015/055557 Al describes a device for introducing a filter-holder into a coffee dispenser, including a cup-shaped container inside which is housed a perforated filter for containing the coffee powder and from which a handle projects. The cup-shaped container has two tabs arranged to engage in a connection element connected to the coffee machine. The connection element includes sliding means inside which the tabs of the cup-shaped container engage sliding along a straight path.

[0012] WO/2017/134141 Al describes a dispensing group for an espresso coffee machine.

[0013] The group includes: a coffee boiler configured to contain pressurized hot water; a supply duct for feeding hot water under pressure towards a puck of coffee powder; and a Filter-holder support including guides which form at least one sliding surface for slidably supporting a filter holder. The filter-holder support is rotatable between a first position for inserting the filter holder and a second dispensing position. The dispensing group includes a mechanical locking device for locking the filter-holder support in the second dispensing position.

[0014] Summary

[0015] According to a first aspect of the invention there is provided an espresso machine.

[0016] The espresso machine includes a support structure which includes three or more support elements. The support structure is configured to receive a multi-basket portafilter which includes two or more apertures, such that the multi-basket portafilter rests on the support elements and at least one support element is disposed on either side of each aperture. Each aperture is configured to receive and support a portafilter basket. The espresso machine also includes a multi-group head assembly supporting a piston assembly corresponding to each of the apertures. Each piston assembly includes a sealing piston including a channel for delivery of heated water to a portafilter basket received by the corresponding aperture. Each piston assembly also includes a gasket received in the sealing piston. Each piston assembly also includes a linear actuator configured, in response to actuation, to urge the sealing piston into contact with the portafilter basket received by the corresponding aperture until the gasket forms a seal between the sealing piston and the portafilter basket.

[0017] In this way, deflection of the multi-basket portafilter may be minimised, allowing for forming seals to two or more portafilter baskets concurrently without excessive deformation of the multi-basket portafilter.

[0018] The support structure may be configured to slidably receive the multi-basket portafilter, or at least a portion thereof which includes the apertures.

[0019] The piston assemblies may be arranged in a linear array. In this way, the espresso machine may be configured to receive, and form seals to, at least one portafilter basket supported in a multi-basket portafilter having two or more apertures arranged in a linear array. When viewed from above, the two or more piston assemblies may be interdigitated with the three or more support elements such that a received multi-basket portafilter will be supported with each aperture bracketed by a pair of support elements.

[0020] Each linear actuator may include a mechanism which includes, or takes the form of, a screw, a worm-gear, a leadscrew, a screw jack, a ball screw, a roller screw, and so forth. Each linear actuator may include a mechanism which includes, or takes the form of, a wheel-and-axle, rack-and-pinion, a chain/belt drive, and so forth. Each linear actuator may include a mechanism which includes, or takes the form of, a cam, a wedge and so forth.

[0021] The seal formed between a sealing piston and a corresponding portafilter basket supported by a received multi-basket portafilter may be watertight to a pressure of at least 6 bar. Preferably, the seal formed between a sealing piston and a corresponding portafilter basket supported by a received multi-basket portafilter may be watertight to a pressure of at least 9 bar. The seal formed between a sealing piston and a corresponding portafilter basket supported by a received multi-basket portafilter may be watertight to pressures between (including end-points) 6 bar and 12 bar. The seal may be watertight to pressures exceeding 12 bar.

[0022] The forces applied by the linear actuators may press the multi-basket portafilter against the support elements.

[0023] The espresso machine may be configured such that, for each linear actuator, a force applied urging the sealing piston into contact with the portafilter basket received by the corresponding aperture may be controlled to a predetermined force based on monitoring an electrical current supplied to that linear actuator.

[0024] Each linear actuator may be electrically driven.

[0025] The espresso machine may include one or more sensors. Each sensor may be configured, in response to reception of the multi-basket portafilter within the support structure, to output a signal indicating receipt of the multi-basket portafilter.

[0026] Each sensor may take the form of a magnetic switch configured to respond to a permanent magnet embedded in, or supported by, the multi-basket portafilter. A magnetic switch may include, or take the form of, a reed switch. A magnetic switch may include, or take the form of, a Hall effect sensor. A magnetic switch may include, or take the form of, a magnetoresistive sensor. Alternatively, sensors may take any suitable form including, but not limited to, physical (mechanical) switches, light-gates, completion of one of more resistive or capacitive electrical circuits, and so forth.

[0027] The espresso machine may include at least one sensor corresponding to each piston assembly. The espresso machine may be configured such that, for each piston assembly, the sensor corresponding to that piston assembly outputs a signal indicating whether a portafilter basket is supported in the aperture corresponding to that piston assembly The espresso machine may be configured to actuate one or more of the linear actuators in response to receiving one or more signals from the one or more sensors.

[0028] In a case where the sensor(s) only indicate reception of the multi-basket portafilter, all of the linear actuations may be automatically actuated in response to the signal(s).

[0029] However, in a case where at least one sensor corresponds to each piston assembly, the linear actuators corresponding to signal(s) indicating portafilter baskets have been received may be automatically actuated, and the remaining linear actuators may not be actuated.

[0030] Alternatively, instead of automatically actuating linear actuators, the espresso machine may be configured to utilise the signals from the sensor(s) to provide safety interrupts for manual triggering to actuate linear actuators. For example, the espresso machine may not respond to a manual input to actuate a linear actuator unless the respective sensor is providing a signal indicating that a portafilter basket is present.

[0031] Alternatively still, all linear actuators may be actuatable at any time, and the signal(s) from the sensors may provide safety interrupts preventing to dispense hot water when the multi-basket portafilter is not received and/or to preventing dispensing via any sealing pistons which do not correspond to a received signal indicating that a portafilter basket is present. In this way, even if an aperture is unfilled, the corresponding sealing piston may be pressed against the multi-basket portafilter. This may provide additional clamping force and/or improve uniformity of force and sealing pressure across the multi-basket portafilter when some apertures are not in use.

[0032] The espresso machine may also include one or more user input controls configured to permit controlling the linear actuators.

[0033] Actuation of a corresponding linear actuator, whether automatically or manual by user input, may automatically trigger supplying hot water to each sealed portafilter basket received by the espresso machine. Alternatively and preferably, supply of hot water to each sealed portafilter basket received by the espresso machine may be made in response to receiving manual input via one or more further user input controls.

[0034] The further user input controls may be configured to permit input to supply hot water to a subset of the sealed portafilter baskets. For example, in a three aperture multi-filter portafilter, each aperture may receive a filled portafilter basket. An operator may load this into the support structure and automatically or manually seal the respective sealing pistons to each of the filled portafilter baskets. They may then dispense an espresso using one, or a pair of the filled portafilter baskets, leaving the remaining filled portafilter basket(s) to use later.

[0035] All of the support elements of the support structure may be formed as extensions from a single baseplate part.

[0036] Alternatively, some or even all of the support elements may be formed individually and connected to the espresso machine in a suitable manner. For example, each support element may be received into a corresponding slot formed in the espresso machine to form a cantilevered support element.

[0037] Each support element may be elongated with a proximal end connecting to the espresso machine and a distal end. The support structure may include one or more vertical braces. Each vertical brace may conned the multi-group head assembly to the support element between the proximal and distal ends.

[0038] A vertical brace may include, or take the form of, one or more columns. A vertical brace may include, or take the form of, a wall. A vertical brace may be included connecting to every support element between the proximal and distal ends.

[0039] The vertical braces may be connected (for example via the support structure) to a structural element of the multi-group head assembly which supports the linear actuators. In this way, actuation of one or more linear actuators will press the multi-basket portafilter against the support elements such that each vertical brace will be loaded in tension along a respective axis. This may help to further minimise any deflection of the multi-basket portafilter during sealing in response to actuation of one or more linear actuators.

[0040] The multi-basket portafilter may include one or more slots arranged to receive the vertical brace(s) when the multi-basket portafilter is received by the support structure. For example, column(s) comprising a vertical brace may be received into the slot, or a wall comprising a vertical brace may be received into the slot.

[0041] Each sealing piston may include windings for induction heating. The espresso machine may be configured to heat portafilter baskets received by one or more apertures of the multi-basket portafilter by energising the windings of corresponding sealing pistons.

[0042] Each sealing piston may include an electrical heating element. The espresso machine may be configured to activate the electrical heating element corresponding to a sealing piston to raise its temperature immediately prior to dispensing hot water via the respective channel. The electrical heating elements may heat the corresponding sealing piston by conductive heating.

[0043] A path for conveying water from a boiler to each of the sealing pistons may also include one or more further electrical heating elements.

[0044] One, a subset, or all electrical heating elements may include, or take the form of, a cartridge heater.

[0045] Each sealing piston may include a temperature sensor, the espresso machine configured to control the temperature of each actuated sealing piston to a target temperature.

[0046] The target temperature may be between 85 °C and 98 °C. For example 93 °C. Preferably the target temperature matches, or is within ±1 °C of, a temperature at which heated water is output from a boiler of the espresso machine. The target temperature is in general variable depending on the recipe and/or beans chosen to brew, and the espresso machine may also include user input controls allowing to set and/or adjust the target temperature.

[0047] The espresso machine may include a flow sensor corresponding to the channel of each sealing piston.

[0048] In this way, the espresso machine may monitor each channel and deliver a consistent volume of heated water through each received portafilter basket.

[0049] Alternatively, the espresso machine may also include a cup/receptacle support corresponding to each piston assembly and coupled to a mass sensor. By monitoring a total mass delivered via each piston assembly, the espresso machine may monitor each channel and deliver a consistent volume of heated water through each.

[0050] The multi-group head assembly may include two piston assemblies. The support structure may be configured to receive a multi-basket portafilter which includes two apertures.

[0051] The multi-group head assembly may include three piston assemblies. The support structure may be configured to receive a multi-basket portafilter which includes three apertures.

[0052] The espresso machine may be configured to operate with 54 mm portafilter baskets.

[0053] The espresso machine may be configured to operate with 58 mm portafilter baskets.

[0054] A boiler of the espresso machine for generating the heated water may not be a steam boiler.

[0055] The espresso machine may include a thermo-block boiler for generating the heated water. The espresso machine may include a separate thermo-block boiler corresponding to each sealing piston.

[0056] According to a second aspect of the invention, there is provided a multi-basket portafilter for reception by the support structure of the espresso machine of the first aspect. The multi-basket portafilter includes a handle portion and a supporting portion. The supporting portion includes two or more apertures. Each aperture is configured to receive and support a portafilter basket.

[0057] The handle portion is connected to the supporting portion. The two or more apertures may be arranged in a linear array. The supporting portion may be plate-like.

[0058] Each aperture may be sized to receive a 54 mm portafilter basket. Each aperture may be sized to receive a 58 mm portafilter basket.

[0059] The supporting portion of the multi-basket portafilter may include one or more slots arranged to receive vertical braces of the support structure of the espresso machine.

[0060] The supporting portion may include two apertures. The supporting portion may include three apertures.

[0061] The supporting portion may be formed of aluminium.

[0062] The supporting portion may include (or support) one or more permanent magnets. The supporting portion may include (or support) two or more permanent magnets. Each permanent magnet may correspond to one of the apertures.

[0063] Each permanent magnet may be positioned such that, when received by the support structure of the espresso machine, the magnetic field of that permanent magnet is detectable be a sensor of the corresponding piston assembly.

[0064] The multi-basket portafilter of the second aspect may include features corresponding to any features of the espresso machine of the first aspect. Definitions applicable to the espresso machine of the first aspect (and/or features thereof) may be equally applicable to the multi-basket portafilter of the second aspect (and/or features thereof).

[0065] A system may include the espresso machine of the first aspect and the multi-basket portafilter of the second aspect The system may include features corresponding to any features of the espresso machine of the first aspect and/or the multi-basket portafilter of the second aspect.

[0066] Definitions applicable to the espresso machine of the first aspect (and/or features thereof) and/or the muti-basket portafilter of the second aspect (and/or features thereof), may be equally applicable to the system (and/or features thereof).

[0067] According to a third aspect of the invention, there is provided a method of using the multi-basket portafilter of the second aspect in the espresso machine of the first aspect. The method includes inserting a portafilter basket filled with coffee grounds into at least one aperture of the multi-basket portafilter. The method also includes inserting the multi-basket portafilter into the support structure of the espresso machine. The method also includes actuating the linear actuator of at least each piston assembly corresponding to a filled portafilter basket to urge the sealing piston into contact with the portafilter basket received by the corresponding aperture until the gasket forms a seal between the sealing piston and the filled portafilter basket. The method also includes passing heated water through at least one of the filled portafilter baskets via the channels of the corresponding sealing pistons.

[0068] Linear actuators of piston assemblies which do not correspond to filled portafilter baskets may also be actuated. Heated water may not be passed through channels of sealing pistons which do not correspond to filled portafilter baskets.

[0069] -10 -The method of the third aspect may include features corresponding to any features of the espresso machine of the first aspect and/or the multi-basket portafilter of the second aspect. Definitions applicable to the espresso machine of the First aspect (and/or features thereof) and/or the muti-basket portafilter of the second aspect (and/or features thereof), may be equally applicable to the method of the third aspect (and/or features thereof).

[0070] According to a fourth aspect of the invention, there is provided an espresso machine configured to receive one or more portafilter baskets, and to form a seal with each received portafilter basket using a corresponding linear actuator. For each received portafilter basket, the espresso machine is configured to control a force applied to seal that received portafilter basket based on monitoring an electrical current supplied to the corresponding linear actuator.

[0071] The espresso machine of the fourth aspect may include features corresponding to any features of the espresso machine of the first aspect and/or the multi-basket portafilter of the second aspect. Definitions applicable to the espresso machine of the first aspect (and/or features thereof) and/or the muti-basket portafilter of the second aspect (and/or features thereof), may be equally applicable to the espresso machine of the fourth aspect (and/or features thereof).

[0072] According to a fifth aspect of the invention, there is provided an espresso machine including a group head housing one or more windings for induction heating, configured to heat a portafilter basket received by the group head. The one or more windings for induction heating may be configured to heat all, or a portion of, a portafilter or multi-basket portafilter supporting the portafilter basket.

[0073] The espresso machine may include one or more electrical heating elements configured to provide supply local conductive heating to all or part of a heated water path extending from a boiler up to and including the group head.

[0074] The espresso machine of the fifth aspect may include features corresponding to any features of the espresso machine of the first aspect, the multi-basket portafilter of the second aspect and/or the espresso machine of the fourth aspect. Definitions applicable to the espresso machine of the first aspect (and/or features thereof), the muti-basket portafilter of the second aspect (and/or features thereof), and/or the espresso machine of the fourth aspect (and/or features thereof) may be equally applicable to the espresso machine of the fifth aspect (and/or features thereof).

[0075] According to a sixth aspect of the invention, there is provided an espresso machine comprising one or more electrical heating elements configured to provide local conductive heating of all or part of a heated water path extending from a boiler up to and including a group head.

[0076] The group head may house one or more windings for induction heating, configured to heat a portafilter basket received by the group head. The one or more windings for induction heating may be configured to heat all, or a portion of, a portafilter or multi-basket portafilter supporting the portafilter basket.

[0077] The espresso machine of the sixth aspect may include features corresponding to any features of the espresso machine of the first aspect, the multi-basket portafilter of the second aspect, the espresso machine of the fourth aspect, and/or the espresso machine of the fifth aspect. Definitions applicable to the espresso machine of the first aspect (and/or features thereof), the muti-basket portafilter of the second aspect (and/or features thereof), the espresso machine of the fourth aspect (and/or features thereof), and/or the espresso machine of the fifth aspect (and/or features thereof) may be equally applicable to the espresso machine of the sixth aspect (and/or features thereof).

[0078] -12 -

[0079] Brief description of the drawings

[0080] Certain embodiments of the present invention will now be described, by way of example, with reference to the accompanying drawings in which: Figure 1 shows a multi-basket portafilter and three-group head assembly; Figure 2 shows a bottom view of the multi-basket portafilter in the group head assembly; Figure 3 shows a front view of the multi-basket portafilter in the group head assembly; Figure 4 shows a linear actuator and piston assembly; Figure 5 shows views of the group head and multi-basket portafilter during the sealing process; Figure 6 shows a simplified schematic of a single portafilter support casing; Figure 7 shows a simplified schematic of a naively designed structure of a multi-basket support case; Figure 8 shows a simplified schematic of a support structure according to the present specification being used in a multi-basket portafilter scenario; Figure 9 shows a multi-basket portafilter with slots to allow insertion around vertical braces of the espresso machine; Figure 10 shows a bottom view of a group head with a hidden baseplate; Figures 11 shows a detailed view of reinforcement screw holes providing vertical braces; Figure 12 shows a section view of a three-piston group head, and a detailed cross section of the piston assembly; Figure 13 is an enlarged version of "DETAIL B" from Figure 12; Figure 14 schematically illustrates reaction forces acting upon a slide in multi-basket portafilter when received into a support structure of an espresso machine; Figure 15 is a side view of an example multi-basket portafilter; Figure 16 is a projection view of the example multi-basket portafilter shown in Figure 15; Figure 17 presents a comparison of the number of tasks required to make different numbers of coffees, between a prior art espresso machine and an espresso machine according to the present disclosure.

[0081] Detailed description

[0082] Espresso making consists of repetitive tasks, which require high levels of consistency throughout the process to deliver high quality coffee. Summarised below are the main problem which the present specification aims to solve: -13 -Address repetitive and inefficient coffee making methods There are three main bottle necks of similar magnitude when making espresso-based drinks. These include (i) preparing the coffee puck contained in the portafilter, (ii) pulling the shot and (iii) pouring the latte art. Currently, one espresso shot is pulled from one single portafilter and group head. The herein newly proposed multi-basket portafilter design, in conjunction with a multi-way dispensing coffee grinder will overcome the first bottleneck by allowing baristas to prepare three coffee pucks simultaneously. This will reduce the number of separate tasks the barista has to perform and free up time. This increase in efficiency will allow café owners to reduce the number of staff required to meet the café throughputs or in busy times allow for faster service resulting in more sales per hour and lower labour costs per sale.

[0083] Wrist strain on baristas due to sealing motion.

[0084] Baristas may suffer from strain in their wrists because of the repetitive force needed to insert the portafilter into the coffee machine and perform the "rotate-to-seal" motion.

[0085] The multi-slide in multi-basket portafilter proposed in the present specification has a smooth and easy to use design, as the sealing may occur automatically once electronic actuators detect the multi-basket portafilter. The user simply slides in the multi-basket portafilter, magnets locate it in place and the actuators move down to seal the baskets.

[0086] Damaging the coffee puck compromises coffee taste.

[0087] Inexperienced and/or rushed baristas may damage the coffee puck when inserting it into the machine, which usually results in either poor coffee taste or remaking the shot, which requires time. The proposed new design reduces the chance of this occurring as there is no resistance encountered by the slide in mechanism. The entrance to the slide in portafilter has a large chamfer that smoothly guides the portafilter into the machine.

[0088] Traditional coffee machines are large and do not fit in small cafes.

[0089] Traditional two or three group head coffee machines take up a lot of space on counters.

[0090] There are two reasons these machines are large. Firstly, they have two boilers, one for water and one for steam. The steam boiler is the component that take up the most space in the machine and is responsible for the large size of typical multi-group machines. Secondly, the portafilter "rotate-to-seal" mechanism requires space in the horizontal axis to allow the user to place the portafilter in at an angle to screw it into the group head. As the group heads are aligned horizontally, this leads to machines taking up significant counter space. Such espresso machines do not fit in cafes with small counter space. For instance, in coffee trucks that receive a lot of customers this can become a large issue, as the number of group heads in the machine (and therefore -14 -the number of espressos that can be pulled simultaneously) is compromised by the size of the espresso machine they can fit in the available space.

[0091] The herein proposed espresso machine which slidably receives a single multi-basket portafilter overcomes this issue, resulting in a significantly more compact machine.

[0092] Moreover, the proposed machine need not be fitted with a steam boiler: as an alternative espresso machines according to present specification may be designed to be paired with milk frothing technologies to produce on demand frothed milk without the need of the barista to steam the milk with a steam wand.

[0093] Given that espresso machines according to the present specification are not limited by the distance between group heads and need not contain a steam boiler, the machine can be significantly reduced in size. It allows for a three-group (or more) head machine to be the size of a prior art single group head machine.

[0094] The proposed espresso machine and multi-basket portafilter can still take in single portafilter baskets if there are times the user does not want to fill/use every portafilter basket supportable within the multi-basket portafilter.

[0095] Example coffee machine Referring to Figures 1 to 3, an example of an espresso machine according to the present specification is shown.

[0096] The proposed espresso machine includes a support structure for slidably receiving a slide in multi-basket portafilter. The multi-basket portafilter holds multiple baskets in a linear array. The portafilter baskets are removable received into apertures in multi-basket portafilter. The multi-group head assembly has been designed so the portafilter can simply slide into the machine.

[0097] In the illustrated example, once the portafilter is receive by the support structure, the linear actuators are automatically engaged using a magnetic switch activated from the portafilter. The linear actuators move down an individual piston assembly to create a seal with the selected portafilter basket.

[0098] Figure 4, shows in more detail the sub-assembly of the sealing piston that houses the seal (gasket) in the exemplary espresso machine. The linear actuators have a current sensor configured to detect (via feedback from current measurements) when the -15 -appropriate sealing force has been applied, in order to then stop moving. The pumps are actuated, and hot water runs through each group head pulling multiple shots at once. Once the required volume of coffee has been dispensed, the linear actuators retract the pistons and allow the user to remove the portafilter and clean it. The portion of the support structure connecting to the linear actuators is omitted in Figure 1 for figure simplicity.

[0099] Machine user procedure The following procedure is applicable to the exemplary espresso machine.

[0100] 1. The user will insert the multi-basket portafilter into the espresso machine by sliding it into the support structure.

[0101] 2. The espresso machine will detect the multi-basket portafilter has been inserted using a magnetic reed switch.

[0102] 3. The pistons will automatically move down by means of the linear actuators sealing each portafilter basket individually.

[0103] 4. The linear actuators use a current feedback loop to detect when the appropriate sealing force has been applied and stop moving.

[0104] 5. The user chooses how many channels they want to pull espresso from, depending on how many baskets they prepared.

[0105] 6. The machine uses a flow sensor for each channel to know when to stop the flow to each channel individually.

[0106] 7. Once finished brewing, the pistons move up freeing the multi-basket portafilter basket to allow the user to empty and prepare the next set of espresso shots.

[0107] Sealing a multi-basket portafilter In conventional espresso machines the (single) portafilter screws into the group head. The group head has a bayonet style fitting that receives the portafilter. The thread is pitched so that approximately half a rotation results in contacting the seal.

[0108] An issue which has previously been a barrier to adoption of a multi-basket portafilter is sealing it. A traditional rotate-to-seal mechanism would not work in a multi-basket espresso machine. Part of the present solution resides in using a slide in mechanism, which allows the user to slide the multi-basket portafilter into the support structure of the espresso machine. In espresso machines according to the present specification, the electronically driven linear actuators move down to make the seal.

[0109] -16 -Figure 5 shows the front, cross section, and bottom view of a three-group head seal assembly of the exemplary espresso machine. Further details of the linear actuators are provided hereinafter.

[0110] At 9 bars of pressure, on a single 54 mm basket, the force (F) applied on the (single) portafilter support casing is approximately 2060 N, see Equations 1 and 2. On a multi-basket portafilter with three baskets the total force is 6180 N. This is a significantly large force given that the deflection of the supporting material of a multi-basket filter has to be low enough to ensure the seal does not break contact with the basket.

[0111] F = P * grz (1) = 9 *105*11-M*10-3)2 =2060N (2) In addition to the multi-basket portafilter being exposed to, in this case, three times the total force (W), the length (L) of the multi-basket portafilter is also approximately three time longer in the case of supporting three portafilter baskets.

[0112] Figure 6, schematically shows a structure of the single portafilter support casing representative of conventional single portafilter basket espresso machines.

[0113] Figure 7, schematically shows a support structure for a multi-basket portafilter which would result from simply placing three outlets next to one another. Using Equations 3 to 5 to compare a single basket case to a three-basket portafilter: W = 3F and! = 3L 25 then -ratio = 64. This shows the deflection on a multi-basket portafilter supporting three portafilter baskets would be 64 times larger (for the same material and thickness) if it was designed by extending the same single portafilter support casing illustrated in Figure 6. Large deflections of the portafilter mean that the baskets deflect further than what the compliant seal (gasket) can handle, resulting in a gap forming, which results in leaking. The same theory applies to a design that accepts 58mm baskets.

[0114] Smax,single w13 Smax,triple 60.66E/ Sratio6 max,triple ntax,single 60.66.El 64 1.8*E/ F.L3 wi2 48E1 3F* (3L)3 -17 -Reducing deflection The solution to reduce the deflection on a multi-basket portafilter is to add additional support elements to the support structure. For example, as schematically shown in Figure 8 for the exemplary espresso machine (as illustrated in Figures 1 and 2 for

[0115] example).

[0116] This reduces deflection, however, makes inserting the multi-basket portafilter into the exemplary espresso machine harder. To overcome the problem of getting around the vertical braces of the support structure, slots are added along the multi-basket portafilter main plate, as shown in Figures 9, 10, and 11.

[0117] The design of the exemplary espresso machine results in a consistent and reliable casing structure for sealing at pressures and temperature of up to 15 bar and 96°C respectively.

[0118] Sealing piston assembly Figure 12 shows a section view of the group head of the exemplary espresso machine, and a detailed cross section of the sealing piston assembly. The sealing piston houses the seal and the shower screen which form the main sealing mechanism in the machine (see Figure 4).

[0119] Figure 13 shows an enlarged of "Detail B" in Figure 12, showing a dimension S. Dimension S determines how much the seal compresses before the piston comes in contact with the portafilter main plate (see Figure 1). The piston has been designed to increase the effective bending stiffness of the portafilter by using the clamping force from the linear actuators to act as additional support for the portafilter main plate. The geometry of the slide in multi-basket portafilter is not axially symmetric, therefore there is a force imbalance on the basket from the water pressure.

[0120] This causes a portafilter basket received in an aperture of the multi-basket portafilter to deflect the main plate of the multi-basket portafilter and break the contact with the seal (gasket) resulting in leaking.

[0121] Figure 14 schematically illustrates reaction forces acting upon a slide in multi-basket portafilter when received into a support structure of the exemplary espresso machine.

[0122] The piston design applies a force between a base plate of the support structure and the portafilter plate, clamping the two together. This restrains the free-floating side of the portafilter plate from deflecting.

[0123] -18 -Current sensing and linear actuator The linear actuators are controlled using a current feedback loop. When the seal in the piston starts to contact the portafilter basket (received in a multi-basket portafilter) the current drawn from the linear actuator motor increases. A current sensor is used to stop the motor after a chosen current threshold has been reached. This results in a consistent sealing force each time.

[0124] There are advantages of using linear actuators for the sealing mechanism. Firstly, they are compact, robust, and have a simple mechanism. Secondly, the current sensors allow the same sealing force to be applied repeatedly, this helps with consistency of espresso brewing as the distance of the coffee puck to the shower screen is consistent.

[0125] WO 2015/055557 Al describes a mechanism that has a single slide in portafilter and also tamps the coffee grounds whilst sealing. The overall mechanism is significantly more complicated that the linear actuator mechanism proposed. Notwithstanding that there is no suggestion to do so, much less any discussion of the support and deflection issues solved in the present specification, the mechanism proposed in WO 2015/055557 Al patent would also be too wide to allow putting multiple baskets side by side.

[0126] Another advantage the presently proposed linear actuator mechanism brings is a large range of motion. This allows the pistons to be moved sufficiently that the multi-basket portafilter can slide in freely with a large clearance gap for fast and easy insertion. This may be contrasted with, for example, WO 2017/134141 Al which describes a slide in (single) portafilter that requires the user to manually open the portafilter mechanism.

[0127] WO 2017/134141 Al describes using a hydraulic piston to seal the portafilter basket.

[0128] The disadvantage of a hydraulic actuator is it results in a more complex system as multiple solenoid valves are required to control the water flow logic. The hydraulic actuator also has less range of motion (compared to a linear actuator) which requires a user to open a clamp mechanism to allow the portafilter to slide in.

[0129] Multi-basket portafilter design The multi-basket portafilter design and the structural interactions it has with the support structure and sealing pistons of the espresso machine are interconnected.

[0130] Figure 15 is a side view of the exemplary multi-basket portafilter for use with the exemplary espresso machine. Figure 16 is a projection view of the exemplary multi-basket portafilter shown in Figure 15.

[0131] -19 -The design of the exemplary multi-basket portafilter has been optimised following structural analysis and has been shown in experimental testing to result in a lightweight, leak free system. Hereinafter, the aspects that make this possible will be explained in more detail.

[0132] Mass reduction and Induction heating As described hereinbefore the sealing piston design increases the effective stiffness of the multi-basket portafilter, which reduces the thickness required to prevent large basket deflections, and therefore leaking. This means the mass of the multi-basket portafilter can be reduced relative to simply making a conventional portafilter wider and adding additional apertures for portafilter baskets. This is an advantage of the multi-basket portafilter, as it would be impractical to operate such an item if the mass was too great.

[0133] A conventional single portafilter weighs around 500 grams. Usually, made from chrome plated brass. Brass is used due to its high thermal mass. As described hereinbefore, traditional portafilters aim to maintain their temperature as much as possible during cleaning and refilling. Moreover, the portafilter basket often fits into a thick brass casing in the single portafilter to help maintain temperature.

[0134] Increasing the mass is not an attractive option in a multi-basket portafilter. It would simply be too heavy for a user to handle comfortably and continuously for long shifts. Therefore, the exemplary multi-basket portafilter has been designed to be a light as possible. However, as a result the thermal mass will also be reduced.

[0135] To maintain the temperature of the exemplary multi-basket portafilter, a different and novel method will be used. Portafilter baskets received by the exemplary multi-basket portafilter will be actively heated using an induction heater positioned on the sealing piston.

[0136] In contrast to having a large mass of brass maintaining the heat of the portafilter basket (as in conventional designs), the present designs will cool down during cleaning and refilling, but will be actively heated up to temperature using an induction heater placed in the sealing piston (see Figure 4).

[0137] Equation 6 is used to calculate the energy required to heat up a portafilter basket by a certain temperature change. A standard portafilter basket weighs approximately 25 grams and the grade of stainless steel typically used has a specific heat capacity of 500 -20 -J/(kg °C). Using a temperature of change of 70°C (heating from 20°C to 90°C) and an assumed heat up time of 4 seconds the power required to heat the basket up, is about 200 W. This power can be achieved by a small induction heater placed on the sealing piston. The temperature change used here is a worst-case scenario, in fast cleaning and refilling the temperature drop will be less. A 4 second heat up time is less than the pre-infusion time, so the water is not going through the puck yet.

[0138] Q = mCaT (6) In addition, a cartridge heater of low wattage (-100W) will be inserted into the sealing piston of the exemplary espresso machine (as shown in Figure 4), to add the capability to heat up the group head on demand. The cartridge heater will be coupled with a thermal switch to ensure the required temperature is reached. This will create a stable temperature water path for the hot water from the water boiler. It will also allow baristas to turn off group heads when demand is low as it will have the capability to be brought up to temperature quickly.

[0139] Being able to control the power of the induction heater(s) and the cartridge heater(s) will allow the espresso machine to have very accurate temperature control of the water path providing a significant advantage over other coffee machines. A well-established technology is the E61 Group Head found in many high-end espresso machines. This technology syphons the hot water from the boiler through the group head during idle maintaining its temperature. The portafilter then relies on conductive heat and high thermal mass to maintain its temperature. In contrast, the herein proposed induction heating system coupled with the cartridge heater will heat up the portafilter baskets actively and quickly. This enables a continuously thermally stable water path resulting in consistent espresso brewing.

[0140] Compared to maintaining a large thermal mass at an elevated temperature, reductions in energy consumption are also expected. In particular, during quiet periods a single piston assembly may be heated for use on demand, with additional piston assemblies being used during busier periods. The innovations of the present specification allow the targeted use of heating energy where and when it is needed.

[0141] Although disclosed herein in the context of espresso machines for use with multi-basket portafilters, the use of an induction heated and/or electrical driven heating elements (such as cartridge heaters) to provide targeted and timely heating is not limited to this -21 -context. The same features would provide similar advantages if implemented in any espresso machine, including those designed to receive conventional, single portafilters.

[0142] Time-saving analysis Modelling the process of creating espresso-based drinks using a conventional coffee machine, conventional grinder, and conventional steam wand versus using the exemplary espresso machine with a three-group head portafilter, a three-way dispensing coffee grinder and steam wand provides insights into the advantages of the presently disclosed espresso machines.

[0143] Figure 17 presents a comparison of the numbers of tasks required to make coffee as a function of the number of coffees, for the conventional technology and the exemplary espresso machine.

[0144] These tasks include cleaning the portafilter, grinding beans, distributing, and tamping, pulling the shot, steaming the milk, and pouring the latte art.

[0145] The most efficient strategy for conventional coffee making was directly compared to the most efficient strategy using the proposed new technology. In this model the following assumptions are made for the conventional coffee workflow: one barista, one grinder, three single portafilters for a three-group head machine. For the workflow with the new proposed coffee machine, the assumptions included: one barista, one three-way grinder, two three basket portafilters for a three-group head machine.

[0146] In both cases to make the workflow the most time and cost efficient the group heads are pumping out shots with as minimal downtime as possible. Tasks are performed simultaneously, for instance, during the grinding of the beans or the pulling of the shot, which as tasks that do not require an active presence, the barista can perform an active task, such as tamping.

[0147] Using a conventional coffee machine to make 9 coffees requires 55 tasks, whilst using the new proposed coffee machine requires 33 (see Figure 17). On average this accounts for a 40 0/0 reduction in the number of tasks required to perform to output the same number of coffees. In this way, throughput may be improved.

[0148] Performing a smaller number of tasks will also allow the barista to concentrate more on any given task, which will most likely aid in the reproducibility of the coffee drink created.

[0149] -22 -In terms of time saving, using the same parameters as above, the proposed coffee machine is estimate to allow making nine coffees 15 % faster than the conventional method (30% if paired with on demand milk frothing technologies which do not require time to froth the milk). The workflow used in the model above is the most optimal, and in reality, there may be more inefficiencies that arise, particularly when changing from one task to another which if anything may increase the relative advantages of a multi-basket portafilter system as described herein.

[0150] An additional advantage of an espresso machine according to the present specification is that eliminating the prior art twisting sealing mechanism may result in lower chances of damaging the coffee puck: a common mistake that occurs when inserting the portafilter into the group head by not inserting it correctly. Cracks in the puck lead to water flowing though the crack instead of the coffee ground which compromises the espresso quality. Moreover, removing the twisting sealing mechanism will in turn remove the strain on the wrists of baristas.

[0151] An additional advantage of an espresso machine according to the present specification is that the compact design of the proposed technology addresses a longstanding challenge faced by small cafes and coffee stalls. Traditional coffee machines are often too large to fit in limited spaces. Having the possibility to use a three-group head machine instead of a two-group head model, coffee businesses can significantly increase their coffee output. Moreover, when paired with the three-basket (or more) portafilter technology, the capacity is further amplified by the enhanced speed and efficiency the system may provide.

[0152] Modifications It will be appreciated that various modifications may be made to the embodiments hereinbefore described. Such modifications may involve equivalent and other features which are already known in the design, manufacture and use of espresso machines, systems and component parts thereof and which may be used instead of or in addition to features already described herein. Features of one embodiment may be replaced or supplemented by features of another embodiment.

[0153] The preceding disclosure has focused on a particular, exemplary espresso machine having three sealing pistons and configured to receive a three-basket portafilter. However, the present invention are not limited to the exemplary espresso machine illustrated and discussed, and the invention is defined by the appended claims.

[0154] -23 -Dependent claim define additional, optional features and combinations thereof. Further optional features and combinations thereof are described in the "Summary" hereinbefore.

[0155] Although claims have been formulated in this application to particular combinations of features, it should be understood that the scope of the disclosure of the present invention also includes any novel features or any novel combination of features disclosed herein either explicitly or implicitly or any generalization thereof, whether or not it relates to the same invention as presently claimed in any claim and whether or not it mitigates any or all of the same technical problems as does the present invention. The applicants hereby give notice that new claims may be formulated to such features and/or combinations of such features during the prosecution of the present application or of any further application derived therefrom.

Claims (25)

1. -24 -Claims 1. An espresso machine comprising: a support structure which comprises three or more support elements, the support structure configured to receive a multi-basket portafilter which comprises two or more apertures, such that the multi-basket portafilter rests on the support elements and at least one support element is disposed on either side of each aperture, wherein each aperture is configured to receive and support a portafilter basket, a multi-group head assembly supporting a piston assembly corresponding to each of the apertures, each piston assembly comprising: a sealing piston comprising a channel for delivery of heated water to a portafilter basket received by the corresponding aperture; a gasket received in the sealing piston; a linear actuator configured, in response to actuation, to urge the sealing piston into contact with the portafilter basket received by the corresponding aperture until the gasket forms a seal between the sealing piston and the portafilter basket.

2. The espresso machine of claim 1, wherein for each linear actuator, a force applied urging the sealing piston into contact with the portafilter basket received by the corresponding aperture is controlled to a predetermined force based on monitoring an electrical current supplied to that linear actuator.

3. The espresso machine of claims 1 or 2, comprising one or more sensors, each sensor configured, in response to reception of the multi-basket portafilter within the support structure, to output a signal indicating receipt of the multi-basket portafilter.

4. The espresso machine of claim 3, comprising at least one sensor corresponding to each piston assembly, and configured such that, for each piston assembly: the sensor corresponding to that piston assembly outputs a signal indicating whether a portafilter basket is supported in the aperture corresponding to that piston assembly

5. The espresso machine of claims 3 or 4, configured to actuate one or more of the linear actuators in response to receiving one or more signals from the one or more sensors.-25 -

6. The espresso machine of any one of claims 1 to 5, comprising one or more user input controls configured to permit controlling the linear actuators.

7. The espresso machine of any one of claims 1 to 6, wherein all of the support elements of the support structure are formed as extensions from a single baseplate part.

8. The espresso machine of any one of claims 1 to 7, wherein each support element is elongated with a proximal end connecting to the espresso machine and a distal end; the support structure comprising one or more vertical braces, each vertical brace connecting the multi-group head assembly to the support element between the proximal and distal ends.

9. The espresso machine of any one of claims 1 to 8, each sealing piston comprising windings for induction heating; wherein the espresso machine is configured to heat portafilter baskets received by one or more apertures of the multi-basket portafilter by energising the windings of corresponding sealing pistons.

10. The espresso machine of any one of claims 1 to 9, each sealing piston comprising an electrical heating element.

11. The espresso machine of claim 10, each sealing piston comprising a temperature sensor, the espresso machine configured to control the temperature of each actuated sealing piston to a target temperature.

12. The espresso machine of any one of claims 1 to 11, comprising a flow sensor corresponding to the channel of each sealing piston.

13. The espresso machine of any one of claims 1 to 12, wherein the multi-group head assembly comprises two piston assemblies, and wherein the support structure is configured to receive a multi-basket portafilter which comprises two apertures.

14. The espresso machine of any one of claims 1 to 12, wherein the multi-group head assembly comprises three piston assemblies, and wherein the support structure is configured to receive a multi-basket portafilter which comprises three apertures.-26 -

15. The espresso machine of any one of claims 1 to 14, wherein a boiler for generating the heated water is not a steam boiler.

16. The espresso machine of any one of claims 1 to 15, comprising a thermo-block boiler for generating the heated water.

17. A multi-basket portafilter for reception by the support structure of the espresso machine according to any one of claims 1 to 16, comprising: a handle portion; and a supporting portion comprising two or more apertures each aperture configured to receiving and support a portafilter basket.

18. The multi-basket portafilter of claim 17, wherein the supporting portion is formed of aluminium.

19. The multi-basket portafilter of claims 17 or 18, wherein the supporting portion comprises one or more permanent magnets.

20. A system comprising: the espresso machine of any one of claims 1 to 16; and the multi-basket portafilter of any one of claims 17 to 19.

21. A method of using the multi-basket portafilter of any one of claims 17 to 19 in the espresso machine of any one of claims 1 to 16, the method comprising: inserting a portafilter basket filled with coffee grounds into at least one aperture of the multi-basket portafilter; inserting the multi-basket portafilter into the support structure of the espresso machine; actuating the linear actuator of at least each piston assembly corresponding to a filled portafilter basket to urge the sealing piston into contact with the portafilter basket received by the corresponding aperture until the gasket forms a seal between the sealing piston and the filled portafilter basket; passing heated water through at least one of the filled portafilter baskets via the channels of the corresponding sealing pistons.

22. An espresso machine configured to receive one or more portafilter baskets, and to form a seal with each received portafilter basket using a corresponding linear actuator; -27 -wherein for each received portafilter basket, the espresso machine is configured to control a force applied to seal that received portafilter basket based on monitoring an electrical current supplied to the corresponding linear actuator.

23. An espresso machine comprising a group head housing one or more windings for induction heating, configured to heat a portafilter basket received by the group head.

24. The espresso machine of claim 23, comprising one or more electrical heating elements configured to provide local conductive heating to all or part of a heated water path extending from a boiler up to and including the group head.

25. An espresso machine comprising one or more electrical heating elements configured to provide local conductive heating of all or part of a heated water path extending from a boiler up to and including a group head.