WO2000051479A2

WO2000051479A2 - Machine for the production of espresso coffee in very large quantities

Info

Publication number: WO2000051479A2
Application number: PCT/EP2000/001643
Authority: WO
Inventors: Giampiero Rossi
Original assignee: Brasilia Spa
Priority date: 1999-03-02
Filing date: 2000-02-28
Publication date: 2000-09-08
Also published as: WO2000051479A3; IT1308635B1; ITMI990416A1; EP1178747A2; AU3283200A

Abstract

Machine for the production of espresso coffee in very large quantities, performing extraction of said coffee from a large mass, or batch, of roasted and ground coffee introduced into a properly extraction set (40) and comprising a cylinder or bucket (36) suitable for housing the batch (108) of roasted coffee powder and co-operating with a piston (38) intended to compress the batch (108) of coffee powder, which piston (38) is provided with a perforated plate filter (110) communicating with means (106) for supplying hot water so to allow the introduction of hot water, and consequent extraction of espresso coffee infusion from the compressed batch (108), which cylinder (36) can be fixed in three different positions which allow loading of a measure (42) constituting the batch (108) of coffee powder, extraction of coffee from the batch (108) of powder and its collection in an appropriate receptacle (112) and, finally, ejection of the coffee batch as an exhausted cake (82), substantially dry, into a collection receptacle (116).

Description

"MACHINE FOR THE PRODUCTION OF ESPRESSO COFFEE IN VERY

LARGE QUANTITIES"

The present invention relates to a machine for the production of espresso coffee in very large quantities and, in particular, a machine which is able to produce espresso coffee by infusing batches of ground coffee weighing up to about one kilogram.

Some food preparation processes require the availability of large quantities of coffee. For example coffee-based drinks are on sale, which can be packaged in cans, to be drunk cold or hot, and also prepared as freeze-dried coffee powder to be made into a coffee drink by simply adding hot water. Certain confectionery industries also need large quantities of coffee for the preparation of particular products, such as dark plain chocolates which contain coffee in the chocolate paste or certain chocolates with a sweetened coffee filling such as those known under the Pocket Coffee® brand.

Nowadays, in order to prepare coffee, at least five distinct methods can be adopted: a first method, which can be defined as the "pot method", consists in adding roasted and ground coffee powder to a pot of water brought to the boil, then decanting the powder and, if necessary, separating the coffee drink from the powder through filtering; a second method, which at present is the one most exhausted for industrial production of coffee infusion, allowing production of both large and small quantities, is the method of "percolation" or so called "filter coffee", which consists in pouring hot water, coming from shower jets or the like, onto a mass of ground coffee (between 10 g and 100 kg for example) enclosed in a bag of filter paper or placed on the perforated base of a receptacle, similar to a tray or pan, and leaving the infusion which forms to percolate gradually through the filter and to collect in a storage receptacle for any further processing; a third method, which can be defined as the "Neapolitan coffeepot method", consists in preparing this coffee by percolating predetermined quantities of hot water at a substantially ambient (or slightly higher) pressure through a mass of roasted and ground coffee in the appropriate quantity and in collecting the infusion obtained in an appropriate tank, as in fact occurs in Neapolitan coffeepots; a fourth method, which can be defined as the "Moka® coffeepot method", consists in preparing this coffee by periodically causing a quantity of water which has been brought to boil to flow through the same mass of roasted and ground coffee, under the pressure of its own steam, finally collecting the infusion in a tank; a fifth method, which can be defined as the "method of the espresso coffee- maker", consists in preparing the coffee from the ground coffee powder exhausted in percolating groups, of the type exhausted in coffee-makers employed in public shops, fed with water brought to the typical temperature and pressure of said coffee-makers.

Naturally the organoleptic characteristics of the coffee obtained are increasingly enhanced when the extraction of the coffee drink from the ground powder takes place at higher and higher temperatures and pressures, so that the pot method is the one which produces coffee in large quantities but with very modest organoleptic properties, whereas the espresso coffee machine method produces coffee in very small quantities since the percolating groups of espresso coffee machines have size suitable for preparing one or, at most, two small cups of coffee, but with the best organoleptic properties which can be obtained.

The evolution in people's taste has led to the demand for coffee drinks whose characteristics are increasingly similar to those of espresso coffee, so that the manufacturers of coffee-based drinks, prepared from freeze-dried coffee, or confectionery products containing coffee, are obliged, in order to retain a sufficiently large market share, to adapt to the widespread tastes of people who nowadays find that the properties of coffee prepared with methods of percolating water at low temperatures are too weak.

Unfortunately, the methods involving lower water pressures and temperatures are particularly suitable for economical production of coffee in industrial quantities, while the espresso coffee machine method is suitable for the production of coffee in industrial quantities only at the cost of using a very large number of espresso coffee- makers with decidedly negative economic consequences, both in terms of energy consumption and use of labour.

There is therefore the need for a machine for the production, in industrial quantities, of a coffee having properties the same as or at least very similar to those of espresso coffee, without the energy and labour costs which would arise from the use of a number of espresso coffee machines such as to allow the production of coffee in reasonable time.

The object of the present invention is precisely that of satisfying the aforesaid need.

The aforesaid object is achieved by an espresso coffee machine comprising: at least one boiler for supplying pressurised hot water; a means for supplying roasted and ground coffee, such as an industrial grinder; an extraction set capable of supplying an infusion of coffee, treating, with hot water supplied by at least one boiler, a batch of roasted and ground coffee powder in the same group; a means of conveying and collecting the coffee infusion leaving the extraction set; a means for collecting the exhausted batch of coffee powder, once the infusion lias been extracted therefrom; characterised in that the extraction set is formed by a hollow cylindrical body with the top face open upwards so as to receive a piston sliding axially in the cavity and the bottom face substantially closed so as to support a base plate which can be raised, in relation to the closed face, and is provided with holes for the through-flow of the infusion, the bottom face being provided with two holes, a first one of which, positioned centrally, has the function of allowing the passage of a rod for pushing the base plate and a second one of which, positioned peripherally at the lowest point of the same bottom face, communicates with external means for the conveying and collection of the infusion obtained; moreover the cylinder is supported externally on rotation means, around an axis perpendicular to the axis of the same cylinder, anchored to support means so that the orientation of the cylinder can vary between a first position, having the open top face directed upwards, for holding the coffee powder, a second position with the top face perpendicular to the piston, for receiving the latter during its axial sliding movement, and a third position, with the same top face directed laterally towards the means for collecting the exhausted batch of coffee powder so that raising of the base plate causes the exhausted powder to fall, in the form of a compact and semi-dried cake, into the same collection means; moreover the axially sliding piston is connected by means of at least one pipe to at least one boiler and is provided, on the side facing the cylinder, with a filter capable of retaining the coffee powder grains but of allowing the pressurised hot water coming from at least one boiler to flow through, when the coffee infusion is extracted from its powder, while the base plate allows the infusion to pass through its holes towards the hole in the bottom face of the bucket connected to the coffee conveying and collection means.

Preferably both the axially sliding piston and the base plate are provided with filters consisting of sheets of non-corrodible metal, such as stainless steel, provided with small holes with a diameter of between one hundredth and one tenth of a millimetre, which are obtained by chemical micro-etching and which ensure a superior uniform distribution of hot water for infusion and retention of the smallest grains of coffee powder.

The piston which slides axially in the cylinder or bucket of the extraction set is moved in a reciprocating manner by a screw shaft engaged in an internally threaded ring nut of a wheel, moved in the two opposite directions by a reversible motor, which shaft is connected to the end distant from the wheel to a plate sliding on guides and integral with the same piston.

Moreover the piston is connected by means of jointed arms to the cylinder in order to control, by its position, the orientation of the same cylinder in the three abovementioned positions.

In particular, when the piston is at the maximum distance from the cylinder, the latter is oriented with its open top face arranged laterally towards the means for collecting the exhausted coffee powder; when the piston is at a distance from the cylinder such as to leave the top face still free, the same cylinder is oriented along a substantially vertical axis so as to receive coffee powder from a metering device in order to form the batch for extraction, and when the piston comes into contact with the cylinder, the axes of the piston and of the cylinder coincide, allowing sliding of the piston in the cylinder.

Preferably, in order to supply hot water to the extraction set, or bucket, several boilers are exhausted, fed with drinking water by means of at least one pump which brings this water to a sufficient pressure for the extraction of an infusion with the characteristics of espresso coffee.

More preferably, the boilers consist of two sets of boilers in series, a main one towards the extraction set and the other secondary one towards the feed pump, so as to allow feeding of the main set with water, already hot, from the secondary set.

Even more preferably, the pumps which feed the boilers consist of a number greater than one.

Again preferably, the boilers supply water to the piston of the extraction set via at least one solenoid valve.

Even more preferably, the number of solenoid valves is greater than one.

The coffee machine according to the present invention is controlled by a microprocessor which takes into account the demands made thereon and controls the coffee batches, the quantities of water and the temperatures of the latter in order to achieve uniform production of espresso coffee.

The features of the present invention are defined in the claims forming the final part of the description thereof. However other features and advantages of the same invention will emerge more clearly from the following detailed description of one of its embodiments considered with reference to the accompanying drawings in which: - Figure 1 is a general front view of the espresso coffee machine of the present invention;

- Figure 2 is a side elevation view of the machine according to the present invention during the step involving loading the coffee powder into the extraction set;

- Figure 3 is a side elevation view of the machine according to the present invention during the step involving extraction of the coffee infusion from the powder batch housed in the extraction set;

- Figure 4 is a side elevation view of the machine according to the present invention during the step involving expulsion of the exhausted coffee powder cake;

- Figure 5 is a cross-section view of a cylinder, or bucket, extraction set of a machine for the preparation of espresso coffee according to the present invention;

- Figure 6 is an overall layout of the wiring diagrams shown in Figures 7 to 10;

- Figure 7 is a wiring diagram of the connection and control portion of a motor of the piston of the extraction set, a grinder motor and motors of pumps for feeding boilers;

- Figure 8 is a wiring diagram for connection and control of resistors for heating boilers and resistors for heating a group for the supply and distribution of hot water to the extraction set of the machine according to the present invention;

- Figure 9 is a wiring diagram for connection and supply of a first part of a control unit of the machine according to the present invention, also comprising the connection to solenoid valves for the supply of water to the extraction set;

- Figure 10 is a wiring diagram of a second part of the control unit of the machine according to the present invention, also comprising an electronic board for a microprocessor performing the controls and commands for operation of the machine according to the present invention;

- Figure 1 1 is a diagram of a hydraulic system of the machine according to the present invention;

- Figure 12 is a general depiction of a program suitable for commanding and controlling a machine according to the present invention; and

- Figures 13 and 14 show a flow-chart illustrating the status of initialisation of the mechanical components of a machine according to the present invention; and - Figures 15 and 16 show a flow-chart illustrating the status of extraction of coffee of the same machine according to the present invention.

We shall first consider Figures 1 to 4 in order to understand the structure of the machine according to the invention. From these figures it can be seen that a machine 20 for preparing large quantities of espresso coffee consists of a load-bearing structure 22 formed by a base 24, a first pair of vertical uprights 26 and a second pair of inclined uprights 28 housing a pair of support columns 30 terminating in bearings seats 32 housing pins 34 for supporting a cylinder or bucket 36 defining a cylindrical cavity directed upwards, which cylinder 36 forms with a piston 38, sized to enter and slide sealingly in the cavity of the cylinder 36, an extraction set 40 (see Figures 1 and 3) designed to extract, tlirough forced percolation of hot water, a coffee drink from a batch of coffee powder housed in the same extraction set, exactly as occurs in traditional espresso coffee machines exhausted in bars and public shops. As depicted in particular in Figure 2, the cylinder 36 can receive, when its open face is directed upwards, a measure of roasted and ground coffee to be compressed into a batch 42, as will be shown in detail in Figure 5 described further below. In order to prepare and measure the coffee powder a remote controlled grinder can be exhausted, such as the grinder 44 depicted in Figure 2, consisting essentially of a hopper container 46 for granular coffee, to be loaded with an appropriate quantity of roasted coffee grains, which supplies a grinding group 48 terminating in a metering device and dispenser 50 having the task of supplying to the cylinder 36 the required measure of ground coffee corresponding to a required batch. Obviously, for particularly large-scale and complex production of coffee, the grinder 44 is replaced by a ground coffee dispenser in the form of a conveyor belt which supplies with said ground coffee, deposited thereon, a metering device and dispenser similar to the metering device and dispenser 50 depicted in Figure 2. The piston 38 slides in opposite directions, along two guides 52 and 54, in the direction of the axis of a threaded shaft 56 which is prevented from rotating and is fixed to a plate 58 fixed, in turn, to the piston 38. The guides 52 and 54 are held rigidly between an upper yoke 60 fixed to the pair of vertical uprights 26 and the pair of bearings seats 32 fixed in turn to the pair of columns 30 integral with the pair of inclined uprights 28. Therefore, the piston 38 can move only in the direction and in the two ways allowed by the guides 52 and 54. The upper yoke 60 houses a gear box 62 which contains a pulley provided with a threaded cylindrical cavity (not shown) which logically has to be considered as engaged with the threaded shaft 56, which wheel is actuated to rotate by a belt 64 which embraces a pulley of an electric motor 66 which can be actuated in both directions.

As can be seen in Figures 2 to 4, the piston 38 is connected to a right-angled member 68 which ends in a joint 70 hingeably connected to an angled arm 72 terminating in a joint 74 which engages slidingly with a shaft 76 which terminates below in a stop 78 and is connected above to a plate 80 which can move from the base of the cylinder 36 as far as its upper opening to allow ejection of a exhausted coffee powder cake 82, as indicated in Figure 4.

We shall now consider Figure 5 also in order to fully understand the configuration and structure of the extraction set 40. Said set 40 is formed by the lower hollow cylinder 36 and by the piston 38 having size to slide sealingly in the cavity of the cylinder 36 where said seal is ensured by an O-ring gasket 84 housed in a circumferential groove of the same piston 38. The cylinder 36 comprises an internal lining 86 surrounded by a band 88 for reinforcement and also providing support since it is connected to pins 34 inserted in the seats 32 of the support columns 30 so that the cylinder 36 can rotate with the pins 34, yet remains at a fixed distance from the base 24 of the load-bearing structure 22 (see Figures 1 to 4). The lining 86 ends in a base 90 of the cylinder 36, resting on a plate 92, on which base a circular plate 80 rests, provided with holes for sliding 96 which connect the top face of the plate 80 with a circular cavity 98 formed in the base 90 of the cylinder 36, which discharges externally through a hole 100 connected to a pipe 102. Returning to the piston 38, it can be seen that its body has, passing through it, channels 104 fed by pipes 106, which must necessarily be flexible so as to allow mobility of the piston 38, yet at the same time must withstand the temperature and pressure of the hot water to be exhausted for extracting the coffee from a batch of powder 108 which is compressed between the piston 38 and the plate 80 located on the base 90 of the cylinder 36. Under the bottom face of the piston 38 a perforated plate filter 110 is located, said filter allowing correct compression of the batch 108 of coffee powder and, simultaneously, the flow of the hot water coming from the pipes 106. The coffee extracted from the batch of powder 108 flows in the pipe 102 and is collected in a receptacle 112 from where it can be periodically drawn for subsequent processing, as required by its specific use.

When extraction of coffee from the batch of powder 108 has finished, this batch is transformed into a substantially dry cake 82 which is ejected, as illustrated in Figure 4, and falls along a chute 114 into a collection receptacle 116 located at the base of the machine 20 according to the invention.

Returning to consider Figures 1 to 5, it can be understood how the espresso coffee machine according to the invention operates. In particular, in Figure 2 it can be seen how the coffee powder is replenished in a measure 42 supplied to the cavity of the cylinder or bucket 36 of the extraction set 40. The box of rotating mechanisms 62 fixed to the yoke 60 raises the threaded shaft 56 until the piston 38 moves into the position shown in Figure 2 where the assembly consisting of right-angled element 68, angled ami 72 and shaft 76, brings the cylinder 36 into the position shown in Figure 2 with the mouth directed upwards under the remote controlled grinder 44. An appropriate command causes a predetermined measure 42 of coffee powder to drop into the cavity of the cylinder 36, where subsequently a downward movement of the piston 38, caused by a downward movement of the threaded shaft 56, compresses the measure 42 of coffee powder into the batch 108 shown in Figure 5. The downward movement of the piston 38 orientates, through the action of the assembly consisting of right-angled member 68, angled arm 72 and shaft 76, the cylinder 36 so that its axis is aligned with the axis of the piston 38 and so that the piston 38 enters the cavity of the cylinder 36 and compresses the measure of coffee 42 into the batch 108. Once the downward stroke of the piston 38 ends, introduction of water at the required temperature and pressure into the pipes 106 causes extraction of the coffee from the powder and its percolation in the circular cavity 98 of the base 90 of the cylinder 36 from where it flows through the pipe 102 towards the receptacle 112 for collecting the prepared coffee.

Once the required quantity of coffee has been extracted from the batch 108, the extraction set 40 must be opened and the exhausted and substantially dry cake 82 of coffee powder ejected from the cylinder 36. This is performed by a movement of fully raising the piston 38, shown in Figure 4. In this case, full raising of the piston 38, achieved by raising the threaded shaft 56 up to a maximum admissible height, forces the angled arm 74 to rotate the shaft 76 into the position shown in Figure 4 and, consequently, to rotate the pins 34 which support the cylinder 36 which thus takes up the position shown in the same Figure 4. At the same time the stop 78 at the base of the shaft 76 hits against an obstacle at the uprights 26, causing sliding of the shaft 76 in a hole 120 on the base 90 of the cylinder 36 so as to cause raising of the plate 80 with consequent ejection of the exhausted cake of coffee powder, which is shown in form of a cake 82 in Figure 4. Subsequent lowering of the threaded shaft 56 causes the return of the cylinder 36 into the position shown in Figure 2, restoring the conditions for introducing a subsequent measure 42 of coffee powder into the cylinder 36 in order to continue with a subsequent extraction cycle.

For an even better understanding of the invention, we shall consider the wiring and electronic diagram of the circuits exhausted in the machine embodied by the same invention, as represented in Figures 7 to 10, and whose overall layout is shown in Figure 6.

Upon examining Figure 7 it can be seen that a three-phase power supply line 130, formed by three phase conductors A, B and C and a ground conductor G, supplies the whole system via a main switch 132. A first three-phase electric motor 66, which has the function of actuating the rotating mechanism for movement of the threaded shaft 56 (see Figures 1 to 4), is driven in the two directions of rotation by two relays which are equipped with contacts 134 and 136 and which connect the three conductors A, B and C of the three-phase line to the motor 66. Obviously, when the contacts 134 are closed, the motor 66 rotates in one direction, and when the contacts 136 are closed, the motor 66 rotates in the opposite direction. A second three-phase electric motor 138, which actuates the grinder 44 shown in Figure 2, is connected by means of three relay contacts 140 to the same three-phase line in order to maintain continuously a certain quantity of ground coffee in the dispenser 50 of the grinder 44. Finally two relay contacts 142 connect three single-phase motors 144, 146 and 148 of pumps to two phase conductors, for example the conductors A and C, of the electrical power supply line. Obviously these three motors 144, 146 and 148 will only be driven to rotate when there is a demand for supply of water to one or more boilers which will be further depicted below in Figure 11.

Now moving on to examine Figure 8, it can be seen that three relay contacts 150 connect six electric resistance heaters 152 to 162 for boilers to the conductors A, B and C of the three-phase line. Each heater 152 to 162 is provided with a respective adjustable thermostat 164 to 174 which controls the water temperature in the boiler, with a respective working thermostat 176 to 186, regulated to a fixed temperature above the maximum temperature controlled by the adjustable thermostat 164 to 174 and with a respective safety thermostat 188 to 198, of the manually resettable type, which is only tripped in the event of a fault in both thermostats - adjustable and working - in order to disconnect the heaters 152 to 162 from the three-phase line. Obviously manually resettable thermostats are exhausted as safety thermostats in order to be able to re-activate the heaters only when the respective thermostats 164 to 174 and 176 to 186, found to be faulty, have been repaired and/or replaced. Indicator lights 200 to 210 indicate which of the resistance heaters 152 to 162 are connected to the three-phase line. At last, a virtual contact 212 of a static relay connects resistance heaters 214 to 218 to two phase conductors, for example the conductors A and B of the three-phase line, where these resistance heaters are exhausted for auxiliary heating of a hot water distribution group depicted in Figure 11 , to which reference may be made.

Moving on now to consider Figure 9, it can be seen that two conductors A and B of the three-phase line continue so as to be connected, via a switch 220, to a voltage step-down transformer 222 which powers, via a pair of conductors 224 and 226, low voltage circuits for controlling relay coils and for powering electronic boards for the control of all the machine functions. In the same way, the conductors A and B of the three-phase line are connected via a pair of relay contacts 228 to an assembly of solenoid valves 230 to 248 for controlling the supply of water from the boilers to the piston 38 of the extraction set 40. The conductor 226 is also connected to two normally open push-buttons 250 and 252 which, by means of two conductors 254 and 256, allow manual control of two relays controlling the forward and backward movement of the motor 66 for moving the piston 38, should an electronic board for driving the same relays and depicted in Figure 10 be not working.

Considering Figure 10, it can be seen that the second part of the control unit of the machine comprises the two power supply conductors 224 and 226, the conductors 254 and 256 connected to the manual control push-buttons 250 and 252 of Figure 9, a first electronic board 260 for the general control of the machine, relay coils to be described in detail hereinbelow, and a second electronic board 262 for controlling the temperature of the resistance heaters 214 to 218 of an auxiliary group for distribution of hot water, depicted in Figure 8.

The first electronic control board 260, which is a digital board controlled by a microprocessor, receives a supply voltage from the two power supply conductors 224 and 226 and emits currents for energising relay coils, such as the coil 134R which closes the relay contacts 134 for the forward running of the motor 62, the coil 136R which closes the relay contacts for the reverse running of the motor 62, the coil 140R which closes the relay contacts 140 of the grinder motor 138, the coil 142R which closes the relay contacts 142 for the motors 144 to 148 of the pumps for supplying the boilers of the machine and the coil 228R which closes the relay contacts 228 of the solenoid valves 230 to 248. Obviously, energisation of the coils 134R and 136R of the control relays of the motor 62 is controlled by auxiliary interlocking contacts 136A and 134A, respectively, for preventing simultaneous energisation of both coils 134R and 136R and consequent simultaneous closure of the contacts 134 and 136 which would lead to a short-circuit between the conductors A and C of the three- phase line 130, to be absolutely avoided. On the same basis, the coils 134R and 136R are also controlled by limiting switches 134B and 136B, respectively, which prevent the threaded shaft 56 and the piston 38 from going beyond the normal ends of its stroke. The same digital board 260 also receives command signals from push-buttons 264, 266 and 268 which connect its respective input lines 270, 272 and 274 to a common conductor 276, for example negative, marked by the (-) sign, for performing manual commands such as a command for a first measure of water to the machine by the push-button 162, a second measure of water by the push-button 266 and stopping by the push-button 268, respectively. Again the same digital board 260 switches on, as required, one of the indicator lights 280 or 282 by means of respective lines 284 and 286 to indicate which measure of water to be sent to the machine has been chosen. The same board 260 has, departing from it, two power supply lines (-) and (+) as well as a line 288 providing a signal of a measure supplied from a water metering circuit 290 so as to determine a measure of water to be sent into the boilers to obtain a predefined quantity of coffee infusion from each batch 42 of powder introduced into the cylinder 36 of the extraction set 40. In this circuit a special switch 292 supplies power to a coil 150R which closes the contacts of the relay 150 for the boiler heaters 152 to 162 and the auxiliary heaters 214 to 218 of the hot water distribution group and also to the analogie board 262 which, by means of a thermocouple 294, reads the temperature of the boiler hot water distribution set and, by means of a control section 212A, energises the static relay 212 which controls with precision this temperature of the distribution set. The exact operation of the digital electronic board 260 will be understood more clearly further below by considering the flow-chart governing this board and depicted in Figures 12 to 16.

A hydraulic plant diagram of the machine according to the invention is depicted in Figure 11. According to this diagram, water, coming from a pipe 300 of a drinking water system, passes through a filter 302, a turbine metering device 304 of electronic type, which controls the metering circuit 290 depicted in the wiring diagram of Figure 10, and arrives to three pumps 306 to 308 which are driven by respective motors 144 to 148 and which bring the pressure of the water from the mains pressure to that required for extracting the coffee. One-way shut-off valves 312 to 316 are located between the pumps 306 to 310 and a first group of boilers 318 to 322 which perform a first increase in temperature of the feed water (for example from the mains temperature to 60°C) and other shut-off valves 324 to 328 are located between the first group of boilers 318 to 322 and a second group of boilers 330 to 334, where this second group of boilers fully heats the feed water (for example from 60°C to 98°C). Pipes 336 to 340 depart from the boilers 330 to 334 and lead to a water supply set 342 containing the solenoid valves 230 to 248 already indicated in Figure 9. The supply set 342 leads to a distributor set 344 which distributes the water coming from the solenoid valves 230 to 248 of the supply set 342 to the flexible pipes 106, already depicted in Figure 5, which convey the hot water to the channels 104 passing through the body of the piston 38.

The digital electronic board 260 contains a microprocessor controlled by a program generally depicted in Figure 12. Referring to this Figure, it can be seen that the program is written on the principle of a system of statuses and events. Each status has its specific function which is activated in the case of a defined event.

The statuses created are: INITIALISATION 400: initialisation of the circuits and of the mechanical components;

READY 402: indication of machine ready for operation;

COFFEE 404: management of all aspects for preparing a cycle of 1 kg of coffee powder;

PROGRAMMING 406: programming of the product data, quantity of water, coffee grinding time and user language choice; STATISTICS 408: statistical treatment of the product data; ERROR 410: management of errors and display of messages regarding the same.

As can be clearly seen in Figure 12, machine switch-on or surveillance initialisation starts the status 400 of INITIALISATION which examines and tests all the mechanical, electromechanical and electronic components of the machine. If the tests are passed, the READY status 402 is assumed, with the "initialisation performed" sequence. If the tests are failed, the ERROR status 410 is assumed, with the "error" sequence. Once the READY status 402 has been entered into, this status can give a command to prepare coffee in the COFFEE status 404, which status, once terminated, sends back to the ready status 402 a "product made" message. The program can alternate between these two statuses 402 and 404 until the required quantity of coffee has been prepared. Should some coffee preparation parameters have to be changed, or the user interaction language changed, the READY status 402 commands the PROGRAMMING status 406 to program new measures of water, new grades of grinding of the coffee or choose a particular language. The PROGRAMMING status 406 sends the command messages to the COFFEE status 404 and an end-of-programming response to the READY status 402. Should the PROGRAMMING status 406 not succeed in performing some of the tasks assigned to it by the READY status 402, it sends an error message to the ERROR status 410. Again the READY status 402 periodically sends statistics production messages to the STATISTICS status 408 which displays by writing means, both virtual and real (printouts), the statistical data of the product, such as, for example, quantity of coffee (for example in litres) and degree of concentration of the same. Once the statistics have been produced, the STATISTICS status 408 sends a "statistics produced" response message to the READY status 402. Should the STATISTICS status 408 not succeed in performing its task, it sends an error message to the ERROR status 410. Again the ERROR status 410 receives other error messages from other components of the machine, such as the piston 38 beyond the permitted stroke, lack of water, lack of coffee, inadequate voltages, pressures or temperatures, and displays them, controlling the indicator lights and/or a display exhausted in the standard art of control processors.

We shall now consider in detail the program of the initialisation status 400. This status begins with the start block 420 and then passes into the section 422 for movement of the piston 38 into the upper limit position. A decision block 424 asks whether this position has been reached. If YES, an instruction block 426 commands a wait of 2 seconds. If NO, a decision block 428 asks whether a time of 12 seconds has elapsed. If this time has not elapsed (NO), the procedure returns to the "position reached" decision block 424 from where it is possible to branch off to the block 426 or again to the block 428. If this time has elapsed (YES), the procedure passes to the ERROR status such as the indicated ERROR 5 of the block 430.

Should the upper limit position of the piston 38 have been reached and the waiting time of 2 seconds have elapsed, the procedure passes to the section 432 for movement of the piston 38 out of the upper limit position. This section begins with a decision block 434 which asks whether the position has been left. If YES, the procedure continues to the next section. If NO, the procedure passes to a decision block 346 which asks whether a waiting time of 3 seconds has elapsed. If NO, the procedure returns to the previous decision block 434. If YES, the procedure passes to the ERROR status such as the indicated ERROR 7 of the block 438.

When the piston has left the upper limit position, the procedure passes to the section 440 for movement of the piston 38 into the position for pressing inside the cylinder 36. A first decision block 442 asks whether this position has been reached. If YES, an instruction block 444 follows and commands a wait of 2 seconds in that position. If NO, a decision block 446 asks whether a time of 10 seconds has elapsed. If NO, the procedure returns to the decision block 442. If YES, the procedure passes to the ERROR status such as the indicated ERROR 3 of the block 448.

Continuing onto the next page of the program of the status 400, the procedure passes to a section 450 for movement of the piston 38 outside of the cylinder. In this section a decision block 452 asks whether the previous position has been left. If YES, the procedure continues to the next section. If NO, a decision block 454 asks whether a time of 3 seconds has elapsed. If NO, the procedure returns to the previous decision block 452. If YES, the procedure passes to the ERROR status such as the indicated ERROR 8 of the block 456. The next section 458 controls the movement of the piston 38 into the upper limit position. A decision block 460 asks whether the position has been reached. If YES, an instruction block 462 commands a wait of 2 seconds in this position. If NO, a decision block 464 asks whether a time of 12 seconds has elapsed. If NO, the procedure returns to the previous block 460. If YES, the procedure passes to the ERROR status such as the indicated ERROR 5 of the block 466.

Once the time of 2 seconds of the block 462 has elapsed, the procedure passes to the section 468 for movement of the piston 38 out of the upper limit position. A decision block 470 asks whether the preceding position has been left. If YES, the procedure continues to the next section. If NO, the procedure passes to a decision block 472 which asks whether a time of 3 seconds has elapsed. If NO, the procedure returns to the decision block 470. If YES, the procedure passes to the ERROR status such as the indicated ERROR 7 of the block 474.

The next section 476 controls the movement of the piston 38 into the ready position for filling, such as the one shown in Figure 2. In this section a decision block 478 asks whether the position has been reached. If YES, the procedure passes to an instruction block 480 which commands a wait of 5 seconds. If NO, the procedure passes to a decision block 482 which asks whether a time of 10 seconds has elapsed. rf NO, the procedure returns to the position before the decision block 478. If YES, the procedure passes to the ERROR status such as the indicated ERROR 6 of the block 484.

Once the time of 5 seconds of the instruction block 480 has elapsed, the procedure passes to the end block 486 indicating the end of the initialisation status program 400.

We shall now consider in detail the program of the coffee production status 404. This status begins with the start block 490 and then passes to a decision block 492 which asks whether the piston 38 is in the coffee filling position as shown in Figure 2. If YES, the procedure passes to the next section. If NO, the procedure passes to the ERROR status such as the indicated ERROR 1 of the block 494.

The next section 496 controls grinding of coffee for a predetermined period of time. This section begins with a decision block 498 which asks whether the programmed grinding time has passed. If YES, an instruction block 500 commands a further wait of 2 seconds. If NO, the procedure passes to a decision block 502 which asks whether a time of 62 seconds has elapsed. If NO, the procedure returns to the previous decision block 498. If YES, the procedure passes to the ERROR status such as the indicated ERROR 2 of the block 504.

The next section 506 controls the movement of the piston 38 into the position of pressing inside the cylinder 36 of the extraction set 40. This section begins with a decision block 508 which asks whether the piston 38 has reached the position. If YES, then the procedure passes to the instruction block 510 which commands a wait of 2 seconds. If NO, the procedure passes to a decision block 512 which asks whether a time of 12 seconds has elapsed. If NO, the procedure returns to a position before the decision block 508. If YES, the procedure passes to the ERROR status such as the indicated ERROR 3 of the block 514.

The section 516 controls start-up of the water pumps 306 to 310 depicted in Figure 1 1. A first decision block 518 asks whether a predetermined quantity of water has been transferred, measured, for example, by the turbine metering device 304 depicted in Figure 11. If YES, an instruction block 520 commands a wait of 1 second. If NO, the procedure passes to a decision block 522 which asks whether a time of 10 seconds has elapsed. If NO, the procedure returns to the previous decision block 518. If YES, the procedure passes to the ERROR status such as the indicated ERROR 4 of the block 524.

Continuing onto the next page of the program of the status 404, the procedure passes to a section 526 controlling a forward movement of the piston 38 for pressing a exhausted coffee powder cake 82. This section comprises an instruction block 528 which commands a pressing time and a subsequent instruction block 530 which commands a wait of 6.5 seconds.

The abovementioned section having ended, the procedure passes to a section 532 which controls the movement of the piston 38 outside of the cylinder 36. In this section a decision block 534 asks whether the previous position has been left. If YES, the procedure passes to the next section. If NO, the procedure passes to a decision block 536 which asks whether a time of 3 seconds has elapsed. If NO, the procedure returns to the previous block. If YES, the procedure passes to the ERROR status such as the indicated ERROR 8 of the block 538.

A following section 540 controls the movement of the piston 38 into the upper limit position. In this section a decision block 542 asks whether the upper limit position of the piston 38 has been reached. If YES, an instruction block 544 commands a wait of 5 seconds. If NO, the procedure passes to a decision block 546 which asks whether a time of 12 seconds has elapsed. If NO, the procedure returns to the previous block 542. If YES, the procedure passes to the ERROR status such as the indicated ERROR 5 of the block 548.

A following section 550 controls the movement of the piston 38 into the position outside of the upper limit position. In this section a decision block 552 asks whether the piston 38 has left the abovementioned upper limit position. If YES, the procedure proceeds to the next section. If NO, the procedure proceeds to the next decision block 554 which asks whether a time of 3 seconds has elapsed. If NO, the procedure returns to the previous block 552. If YES, the procedure passes to the ERROR status such as the indicated ERROR 7 of the block 556.

Finally a last section 558 of the status 404 of preparation of coffee controls the movement of the piston 38 into the ready position for filling of the cylinder 36 with a measure 42 of coffee powder. In this section 558 a decision block 560 asks whether the piston 38 has reached the required position. If YES, the procedure ends with the block 566 of end of coffee preparation status. If NO, the procedure passes to a decision block 562 which asks whether a time of 10 seconds has elapsed. If NO, the piocedure returns to the previous decision block 560. If YES, the procedure passes to the ERROR status such as the indicated ERROR 6 of the block 564.

What has been described above is an embodiment of the invention not to be considered limiting m any way. For example the number of boilers to be exhausted may differ from that here depicted and a single boiler could also be exhausted m place of the series connected boilers here depicted. Again, in place of the grinder 44, a store of aheady ground coffee could also be exhausted. In the same way, instead of using the turbine water metering device 304, other known volumetric meters for liquids may be exhausted. The number of the pumps 306 to 310 for providing with water the boileis could also vary and could be greater or smaller.

Claims

1. Machine for the production of espresso coffee in very large quantities comprising: at least one boiler (318) for supplying hot water under pressure; a means (44) for supplying roasted and ground coffee, such as an industrial grinder; an extraction set (40) capable of supplying an infusion of coffee, treating with the hot water supplied from at least one boiler (318) a batch (108) of roasted and ground coffee powder in the same extraction set (40); a means for conveying (102) and collecting (112) the coffee infusion leaving the extraction set (40); a means (116) for collecting the cake (82) of exhausted coffee powder, once the infusion has been extracted therefrom; characterized in that the extraction set (40) is formed by a hollow cylindrical body (36) with the top face open upwards so as to receive a piston (38) sliding axially inside the cavity and the bottom face (90) substantially closed so as to support a base plate (80) which can be raised in relation to the closed face and is provided with holes (96) for the through-flow of the infusion, the bottom face (90) being provided with two holes, a first one of which (120), positioned centrally, has the function of allowing the passage of a rod (76) for pushing the base plate (80), and a second one of which (100), positioned peripherally at the lowest point of the same bottom face, communicates with external means (102) for conveying and collecting the infusion obtained; moreover the cylinder (36) is supported externally on rotation means

(34), around an axis perpendicular to the axis of the cylinder (36), anchored to support means (32) so that the orientation of the cylinder

(36) can vary between a first position, having the open top face directed upwards, for holding the coffee powder (42), a second position with the top face perpendicular to the piston (38), for receiving the latter during its axial sliding movement, and a third position, having the same top face directed laterally towards the means (116) for collecting the exhausted coffee powder batch so that raising of the base plate (80) causes the exhausted powder fall, in the form of a compact and half-dried cake (82), into the same collection means (116); moreover the axially sliding piston is connected by means of at least one pipe (106) to at least one boiler (318) and is provided, on the side facing towards the cylinder (36), with a filter (110) capable of retaining the coffee powder grains but of allowing the through-flow of the pressurised hot water coming from at least one boiler (318), when the infusion of coffee is extracted from its powder, while the base plate (80) allows the through-flow of the infusion through its holes (96) towards the hole (100) in the bottom face (90) of the cylinder (36) connected to the means for conveying (102) and collecting (112) coffee.

2. Machine for the production of espresso coffee, as claimed in Claim 1, characterized in that both the axially sliding piston (38) and the base plate (80) are provided with filters consisting of non-corrodible sheets of metal, such as stainless steel, provided with small holes with a diameter of between one hundredth and one tenth of a millimetre, which are obtained by chemical micro-etching and ensure a superior uniform distribution of hot water for infusion and retention of the smallest coffee powder grains.

3. Machine for the production of espresso coffee, as claimed in Claim 1 or 2, characterized in that the piston (38) which slides axially in the cylinder or bucket (36) of the extraction set (40) is driven in a reciprocating manner by a screw shaft (56) engaged in an internally threaded ring nut of a wheel, driven in the two opposite directions by a reversible motor (66), which shaft (56) is connected to the end distant from the wheel to a plate (58) sliding on guides and integral with the same piston (38).

4. Machine for the production of espresso coffee, as claimed in Claims 1, 2 and 3, characterized in that the piston (38) is connected by means of jointed arms (68, 72) to the cylinder (36) so as to control, by its position, the orientation of the same cylinder (36) in the three abovementioned positions.

5. Machine for the production of espresso coffee, as claimed in Claim 4, characterized in that, when the piston (38) is at the maximum distance from the cylinder (36), the latter is oriented with its open top face arranged laterally towards the means (116) for collecting the exhausted coffee powder (82), when the piston (38) is at a distance from the cylinder (36) such as to leave the top face still free, the same cylinder (36) is oriented along a substantially vertical axis so as to receive coffee powder (42) from a metering device (50) in order to form the batch for the extraction and, when the piston (38) comes into contact with the cylinder (36), the axes of the piston (38) and of the cylinder (36) coincide, allowing sliding of the piston in the cylinder.

6. Machine for the production of espresso coffee, as claimed in the preceding claims, characterized in that in order to provide hot water for the extraction set (40) several boilers (318-334) are exhausted, supplied with drinking water by at least one pump (306) which brings this water to a pressure sufficient for the extraction of an infusion with the properties of espresso coffee.

7. Machine for the production of espresso coffee, as claimed in Claim 6, characterized in that the boilers (318-334) are formed as two sets of series connected boilers, a main set (330-334) towards the extraction set (40) and the other secondary set (318-322) towards the feed pump or pumps (306-310), so as to allow feeding of the main battery with water which is already hot from the second set.

8. Machine for the production of espresso coffee, as claimed in Claims 6 and 7, characterized in that the pumps (306-310) which feed the boilers (318-334) are more than one in number.

9. Machine for the production of espresso coffee, as claimed in the preceding claims, characterized in that the boilers (318-334) supply water to the piston (38) of the extraction set (40) via at least one solenoid valve (230).

10. Machine for the production of espresso coffee, as claimed in Claim 9, characterized in that the number of solenoid valves (230-248) is greater than one.

1 1. Machine for the production of espresso coffee, as claimed in the preceding claims, characterized in that it is controlled by a microprocessor (260) which takes into account the demands made thereon and controls the batches of coffee, the quantities of water and the temperatures of the latter so as to obtain the uniform production of espresso coffee.