Automatic coffee machine provided with a coffee discharge pipe purifier

Abstract

The present invention relates to an automatic coffee machine (1) having a control circuit (60), a dispensing head (50) including at least one coffee outlet (51), and a brewing device (10) including a brewing chamber (12) having an upper opening (16) for receiving coffee grounds and a pressure piston (14) movable between an upper retracted position and a lower pressing position. In the upper retracted position, the pressure piston is located above the brewing chamber (12), and in the lower pressing position, the pressure piston enters the brewing chamber (12) through the upper opening (16). The brewing chamber (12) is supplied with hot water by an electric pump (9) and is fluidly connected to at least one coffee outlet (51) through a coffee discharge pipe (30) passing through the pressure piston (14). According to the invention, the vent pipe (40) is connected to the discharge pipe (30) at the engagement area (49) arranged near the pressure piston (14), and the vent pipe (40) includes a solenoid valve (47) that, just after the electric pump (9) stops at the end of the coffee brewing process, the control circuit (60) controls the solenoid valve (47) to switch it from the closed position of the vent pipe (40) to the open position of the vent pipe (40), so that the coffee present in the discharge pipe (30) after the electric pump (9) stops continues to flow with the dispensed coffee under the action of gravity.

Description

TECHNICAL FIELD

[0001] The present invention relates to the general technical field of automatic coffee machines comprising a brewing chamber connected to a dispensing head by a coffee discharge pipe, and more particularly to an automatic coffee machine comprising a coffee discharge pipe purging device. BACKGROUND

[0002] From the documents FR 2 802 073 or FR 2 877 556, an automatic coffee machine is known comprising a control circuit, a dispensing head having at least one coffee outlet and a brewing device. The brewing device comprises a brewing chamber having an upper opening for receiving coffee grounds and a pressure piston movable between an upper retracted position located above the brewing chamber and a lower compacted position into the brewing chamber through the upper opening. The brewing chamber is supplied with hot water by a pump and is fluidically connected to the at least one coffee outlet by a coffee discharge pipe passing through the pressure piston.

[0003] However, at the end of the coffee making process, the brewed coffee remains in the discharge pipe. The residual brewed coffee will be dispensed at the beginning of the next coffee dispensing. Thus, the coffee made after several hours or even several days of inactivity of the automatic coffee machine will be with stale residual coffee that can alter the taste of the coffee.

[0004] Furthermore, if the coffee made is of the ristretto type with a small volume per cup, for example 20 ml, this phenomenon is amplified. The residual coffee can represent about 10% of the volume of coffee. SUMMARY

[0005] The aim of the present invention is to remedy the aforementioned drawbacks and to provide an automatic coffee machine that guarantees a good in-cup result and that has a simple and ergonomic implementation.

[0006] Another aim of the present invention is to propose an automatic coffee machine that is simple in design and economical to operate.

[0007] These aims are achieved by an automatic coffee machine having a control circuit, a dispensing head comprising at least one coffee outlet and a brewing device comprising a brewing chamber provided with an upper opening for receiving coffee grounds and a pressure piston movable between an upper retracted position, in which the pressure piston is located above the brewing chamber, and a lower compacted position, in which the pressure piston enters the brewing chamber through the upper opening, said brewing chamber being supplied with hot water by an electric pump and being fluidically connected to the at least one coffee outlet through a coffee discharge duct passing through the pressure piston, characterized in that a venting duct is connected to the discharge duct at a junction zone arranged in the vicinity of the pressure piston and in that the venting duct comprises a solenoid valve, just after the pump has stopped at the end of the coffee brewing process, the control circuit controls the solenoid valve to switch from a closed position of the venting duct to an open position of the venting duct so that the coffee present in the discharge duct after the electric pump has stopped flows continuously under the effect of gravity following the coffee already dispensed.

[0008] By venting duct is meant venting duct and open air venting duct. Thus, when the solenoid valve is in the open position of the venting duct, the venting duct is connected to open air. In other words, when the solenoid valve is in the open position of the venting duct, the junction zone is connected to the ambient air surrounding the automatic coffee machine, the air being at atmospheric pressure.

[0009] By junction zone arranged in the vicinity of the pressure piston is meant that the junction zone is less than 4 centimeters, preferably less than 1 centimeter, from the pressure piston.

[0010] Thus, the discharge circuit is purged by gravity alone. At the end of the coffee making process, very little coffee remains in the pressure piston until the junction zone.

[0011] Furthermore, at the time of making coffee, the control circuit synchronizes the stopping of the electric pump and the opening of the solenoid valve so that the coffee in the discharge duct continues to flow at the same flow rate. In this way, the user can see the coffee flow continuously. As a result, the discharge circuit is purged without the user noticing or being disturbed, for example because of the discontinuous dispensing of coffee.

[0012] Advantageously, the air duct has an end connected to the solenoid valve and the junction zone is located at a level lower than the end connected to the solenoid valve, the pressure piston being in the lower compacted position.

[0013] Thus, when making coffee, the coffee does not flow upwards along the venting duct to the solenoid valve and therefore does not interfere with its normal operation.

[0014] Preferably, when the pressure piston is in the lower compacted position, the difference in level N1 between the end connected to the solenoid valve and the junction zone is greater than 5 centimeters.

[0015] Advantageously, the venting duct has a length L between the junction area and the solenoid valve, the length L being greater than 10 cm, preferably greater than 20 cm.

[0016] This arrangement ensures that coffee does not flow up the venting duct to the solenoid valve.

[0017] Preferably, the dispensing head is movable in vertical translation between an upper position and a lower position, and the junction area is located above the level of the at least one coffee outlet when the dispensing head is in the upper position and when the pressure piston is in the lower compacted position.

[0018] The draining circuit is thus purged by gravity alone.

[0019] Advantageously, the level difference N2 between the at least one coffee outlet and the junction area is greater than or equal to 10 cm when the dispensing head is in the upper position and when the pressure piston is in the lower compacted position.

[0020] Advantageously, the infusion chamber extends along a vertical axis, and the draining duct has a bent portion extending from the piston top face.

[0021] Preferably, the venting duct has a bent portion arranged above the bent portion of the draining duct, the bent portion of the venting duct being connected to the bent portion of the draining duct at the junction area in the vicinity of the pressure piston top face.

[0022] This arrangement of the bent portion of the venting duct above the bent portion of the draining duct prevents coffee from flowing to the solenoid valve.

[0023] Advantageously, the bent portion of the draining duct and the bent portion of the venting duct are arranged in a vertical plane.

[0024] Preferably, the automatic coffee machine has a milk frothing device provided with a milk and air Venturi suction system from a steam supply pipe, and the milk frothing device has an air supply pipe opening onto the milk and air Venturi suction system, said air supply pipe being opened or closed by a solenoid valve, which is a three-way solenoid valve.

[0025] The solenoid valve thus has two different functions: opening and closing the air supply pipe of the milk frothing device and opening and closing the venting duct of the coffee draining duct. This results in a particularly economical construction.

[0026] Advantageously, the solenoid valve has an air inlet orifice having a diameter less than 0.5 mm.

[0027] This orifice provides a frothing device that makes it possible to produce high-quality milk froth and to ventilate the draining duct so that the coffee present in the dispensing duct flows continuously by gravity. BRIEF DESCRIPTION OF DRAWINGS

[0028] The application will be better understood by studying the embodiments given by way of non-restrictive example and illustrated in the attached drawings in which:

[0029] Figure 1 A perspective view of an automatic coffee machine according to a particular embodiment of the application is shown.

[0030] Figure 2 A perspective view of an automatic coffee machine according to a particular embodiment of the application is shown. Figure 1 A schematic view of an automatic coffee machine is shown.

[0031] Figure 3 A perspective view of an automatic coffee machine according to a particular embodiment of the application is shown. Figure 1 A partial exploded perspective view of an automatic coffee machine is shown, in which the brewing device, the exhaust pipe and the air pipe and the dispensing head are shown with the pressure piston in the upper position.

[0032] Figure 4 A cross-sectional view of the brewing device of an automatic coffee machine is shown along the line IV-IV, with the pressure piston in the lower compacting position, as Figure 3 A cross-sectional view of the brewing device of an automatic coffee machine is shown along the line IV-IV, with the pressure piston in the lower compacting position, as DETAILED DESCRIPTION

[0033] Please note that in this document the terms "horizontal", "vertical", "lower", "upper", "longitudinal", "transverse", "above", "below" used to describe the automatic coffee machine refer to the machine placed on a worktop in use.

[0034] In the embodiment shown in Figures 1 to 4 The automatic coffee machine 1 has a water tank 2 forming a cold water supply, an electric pump 9( Figure 2 ) and a brewing device 10. The brewing device 10 is provided with a brewing chamber 12 fed with coffee grounds from a bean grinder (not shown in the figures). The automatic coffee machine 1 comprises a frame 3, a container support 4 on which containers can be placed and a dispensing head 50 adjustable in height. The dispensing head 50 has a coffee outlet 51. The container support 4 can for example comprise a support grid and a drip tray. The dispensing head 50 is slidably mounted between an upper position, in which the user can place a large cup on the container support 4, and a lower position, in which the user can place a small cup on the container support 4. The dispensing head 50 is slidably mounted on a support plate 5 connected to the frame 3 adjacent to the frame 3( Figure 3 ). The automatic coffee machine 1 has a control circuit 60 to control the preparation of beverages, in particular coffee, based on instructions given by the user.

[0035] As Figures 2 to 4As shown, electric pump 9 supplies water to two instantaneous boilers 13 and 53: boiler 13 produces hot water, and boiler 53 produces steam. Electric pump 9 includes an inlet connected to a water tank 2 for receiving cold water. Electric pump 9 has an outlet connected to a solenoid valve 52, which directs water to boiler 13 to produce hot water or to boiler 53 to produce steam. Brewing device 10 includes a body 11 extending longitudinally along a vertical axis. Body 11 includes boiler 13 and encloses brewing chamber 12 with an upper opening 16. Brewing chamber 12 is capable of accommodating pressure piston 14, which is mounted to be movable along the vertical axis by a drive mechanism. Boiler 13 is used to heat water for brewing coffee in brewing chamber 12. Body 11 is laterally arranged on a single-acting hydraulic cylinder 17, which includes an upper rod 18 ( Figure 4 The system includes a support-like arm 19, the free end of which is connected to a pressure piston 14, such that the stroke directions of the pressure piston 14 and the hydraulic cylinder 17 are parallel. The pressure piston 14 moves between an upper retracted position and a lower pressing position. In the upper retracted position, the pressure piston 14 is positioned above the brewing chamber 12. In the lower pressing position, the pressure piston 14 enters the brewing chamber 12 through the upper opening 16. In the lower pressing position, the pressure piston 14 compresses the coffee grounds entering the brewing chamber 12 to form a compressed coffee cake.

[0036] The boiler 13 and the main body 11 are formed of a heat-conducting material, which includes an electric heating resistor 20, a water passage, and a water heating channel 21. Figure 4 The inlet of the brewing chamber 12 is connected to the cold water tank 2 via an electric pump 9, and its end 22 opens at the bottom of the brewing chamber 12. When the pressure piston 14 is in the lower pressed position, the brewing chamber 12 is fluidly connected to the coffee outlet 51 via the discharge pipe 30. The discharge pipe 30 includes a coffee passage pipe 31 arranged through the pressure piston 14. The coffee passage pipe 31 flows out of the pressure piston 14 through the outlet port 15.

[0037] The electric pump 9 is adapted to generate an upward water circulation in the brewing chamber 12 to the outlet port 15 and the coffee outlet 51. Such a brewing device 10 is described in more detail, for example, in PCT patent application WO9912456.

[0038] like Figure 2 and Figure 3As shown, the automatic coffee machine 1 has a vent pipe 40 for the exhaust pipe 30. The vent pipe 40 connects to the exhaust pipe 30 at an engagement region 49 located near the pressure piston 14. The vent pipe 40 has a solenoid valve 47 electrically connected to a control circuit 60. The solenoid valve 47 includes an air inlet 48. The control circuit 60 controls the solenoid valve 47 to switch from a closed position (where the air inlet 48 is closed) to an open position (where the air inlet 48 communicates with the vent pipe 40). The control circuit 60 reciprocates the switching of the solenoid valve 47 from the open position to the closed position. An end 45 of the vent pipe 40 is connected to the solenoid valve 47. The engagement region 49 is located horizontally below the end 45 connected to the solenoid valve 47, especially when the pressure piston 14 is in the lower pressed position. Figure 2 As shown, when the pressure piston 14 is in the lower pressing position, the horizontal difference N1 between the end 45 connected to the solenoid valve 47 and the engagement area 49 is 6 cm. When the dispensing head 50 is in the upper position and the pressure piston 14 is in the lower pressing position, the engagement area 49 is at a higher level than the coffee outlet 51. When the dispensing head 51 is in the upper position and the pressure piston 14 is in the pressing position, the horizontal difference N2 between the coffee outlet 51 and the engagement area 49 is 10 cm.

[0039] The discharge pipe 30 has a bent portion 32 extending from the top surface 23 of the pressure piston 14 and from the outlet port 15.

[0040] The vent pipe 40 has a bend 41 disposed above the bend 32 of the discharge pipe 30. The bend 41 of the vent pipe 40 connects to the bend 32 of the discharge pipe 30 at an engagement region 49 very close to the top surface 23 of the pressure piston 14. When the dispensing head 50 is in the upper position and the piston 14 is in the lower pressed position, the discharge pipe 30 extends generally downward from the upper end 33 of the bend 32 toward the coffee outlet 51, and the vent pipe 40 extends generally upward from the upper end 42 of the bend 41 toward the solenoid valve 47. The discharge pipe 30 has a flexible portion 34 between the upper end 33 of the bend 32 and the dispensing head 50. The vent pipe 40 has a flexible portion 43 between the upper end 42 of the bend 41 and the solenoid valve 47. Therefore, the flexible portions 34, 43 allow the pressure piston 14 and the dispensing head 50 to move.

[0041] like Figure 2As shown, the automatic coffee machine 1 has a milk frothing device 55 arranged in the dispensing head 50. The milk frothing device 55 has a milk and air venturi suction system 54, which is supplied with steam from a boiler 53. Such a milk frothing device is described, for example, in document EP2606782. The milk frothing device 55 includes a milk supply pipe 56 leading to the suction system, an air supply pipe 57, and a steam supply pipe 58. The air supply pipe 57 is opened or closed by a solenoid valve 47, which is a three-way solenoid valve. A control circuit 60 controls the solenoid valve 47 to switch from the closed position of the air supply pipe 57 (where the air inlet 48 is closed) to the open position of the vent pipe 57 (where the air inlet 48 is connected to the vent pipe 40). The control circuit 60 controls the solenoid valve 47 to switch it from the open position to the closed position of the air supply pipe 57 in a reciprocating manner. The air supply pipe 57 is open to produce a foamed milk beverage, and the air supply pipe 57 is closed to produce a hot milk beverage. The milk frother 55 has a milk beverage outlet 59 near the coffee outlet 51. The air inlet 48 of the solenoid valve 47 has a diameter of 0.3 mm.

[0042] During operation, the user sets the parameters of the control circuit 60 and begins making coffee. After a certain amount of coffee grounds is introduced into the brewing chamber 12, the pressure piston 14 will be in its low-pressure position, and the electric pump 9 will be turned on by the control circuit 60 to deliver water through the boiler 13 to heat the water, which then flows through the grounds contained in the brewing chamber 12 to produce coffee. The coffee then enters the coffee discharge tube 30, formed by the pressure piston's coffee passage tube 31, the bend section 32, and the flexible section 34. The coffee then flows through the coffee outlet 51 into a cup that the user has pre-placed on the container holder 4. Once the pump 9 has injected the amount of water corresponding to the amount of coffee requested by the user, the control circuit 60 cuts off the power to the pump 9 and switches the solenoid valve 47 from the closed position to the open position. This allows air to enter at the engagement area 49, allowing the coffee in the discharge tube 30 to continue flowing at the same speed as its flow rate. As a result, the coffee discharge tube 30 will be completely emptied from the engagement area 49 to the coffee outlet 51.

[0043] Of course, the present invention is not limited to the embodiments described and shown, which are provided merely as examples. Modifications may be made, particularly in the configuration of various elements or through the substitution of equivalent techniques, without departing from the scope of protection of the present invention.

[0044] In a variant of the embodiment, the control circuit 60 has a pinch valve that acts on a flexible portion of the ventilation circuit to open or close the ventilation pipe 40.

Claims

1. An automatic coffee machine (1) having a control circuit (60), a dispensing head (50) comprising at least one coffee outlet (51) and a brewing device (10) comprising a brewing chamber (12) provided with an upper opening (16) for receiving a ground coffee and a pressure piston (14) movable between an upper, retracted position, in which it is located above the brewing chamber (12), and a lower, compacted position, in which it enters the brewing chamber (12) through the upper opening (16), the brewing chamber (12) being supplied with hot water by an electric pump (9) and fluidically connected to the at least one coffee outlet (51) by a coffee discharge duct (30) passing through the pressure piston (14), characterized in that, A venting pipe (40) is connected to the discharge pipe (30) at an engagement area (49) arranged in the vicinity of the pressure piston (14), and the venting pipe (40) comprises a solenoid valve (47), just after the electric pump (9) is stopped at the end of a coffee brewing process, the control circuit (60) controls the solenoid valve (47) to switch it from a closed position of the venting pipe (40) to an open position of the venting pipe (40) so that the venting pipe (40) is connected to open air, coffee present in the discharge pipe (30) after the electric pump (9) is stopped flows continuously under gravity following the coffee already dispensed.

2. The automatic coffee machine (1) according to claim 1, characterized in that, The venting pipe (40) has an end (45) connected to the solenoid valve (47), and the engagement area (49) is located at a level below the level of the end (45) connected to the solenoid valve (47), the pressure piston (14) being in the lower compacted position.

3. The automatic coffee machine (1) according to claim 2, characterized in that, The difference in level between the end (45) connected to the solenoid valve (47) and the engagement area (49) is greater than 5 centimeters when the pressure piston (14) is in the lower compacted position.

4. The automatic coffee machine (1) according to any one of claims 1 to 3, characterized in that, The venting pipe (40) has a length L between the engagement area (49) and the solenoid valve (47), the length L being greater than 10 centimeters.

5. The automatic coffee machine (1) according to any one of claims 1 to 3, characterized in that, The dispensing head (50) is vertically translatable between an upper position and a lower position, and the engagement area (49) is located at a level above the level of the at least one coffee outlet (51) when the dispensing head (50) is in the upper position and when the pressure piston (14) is in the lower compacted position.

6. The automatic coffee machine (1) according to any one of claims 1 to 3, characterized in that, The brewing chamber (12) extends along a vertical axis, and the discharge pipe (30) has a bent pipe portion (32) extending from a top face (23) of the pressure piston (14).

7. The automatic coffee machine (1) according to claim 6, characterized in that, The venting pipe (40) has a bent pipe portion (41) arranged above the bent pipe portion (32) of the discharge pipe (30), the bent pipe portion (41) of the venting pipe (40) being connected to the bent pipe portion (32) of the discharge pipe (30) at the engagement area (49) in the vicinity of the top face (23) of the pressure piston (14).

8. The automatic coffee machine (1) according to claim 6, characterized in that, The bent pipe portion (32) of the discharge pipe (30) and the bent pipe portion (41) of the venting pipe (40) are arranged in a vertical plane.

9. The automatic coffee machine (1) according to any one of claims 1 to 3, characterized in that, It has a milk frothing device (55) provided with a milk and air venturi suction system (54) from a steam supply pipe (58), and the milk frothing device (55) has an air supply pipe (57) opening into the milk and air venturi suction system (54), the air supply pipe (57) being opened or closed by the solenoid valve (47), which is a three-way solenoid valve.

10. The automatic coffee machine (1) according to claim 9, characterized in that, The solenoid valve (47) has an air inlet hole (48) with a diameter less than 0.5 millimeters.

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