DE102011118464B4 - THREE-WAY SOLENOID VALVE FOR A FLUID FEED CIRCUIT, PARTICULARLY FOR A COFFEE OR SIMILAR BEVERAGE MAKING MACHINE - Google Patents

Abstract

Three-way electrovalve for a fluid supply circuit (1), in particular for a coffee or similar beverage making machine, the electrovalve (8) having a valve body (12) defining a compartment (13); a first and a second inlet line (14, 15) to the space (13); a discharge line (16) from the space (13); first closing means (17) and second closing means (18) for interrupting communication between the space (13) and the discharge line (16) and between the second inlet line (15) and the space (13); an electromagnetic actuator (19) for controlling at least the position of the first shutter (17); and a hydraulic device for preventing reverse flow from the first inlet line (14) to the second inlet line (15), the hydraulic device comprising a check valve (20) arranged at the entrance of the second inlet line (15) placed in the space (13); more specifically the non-return valve (20) is placed inside the space (13), the first closure means (17) being connected to a rod (25, 30) movable along a given axis (A) and to the electromagnetic actuator (19), and wherein the stem (30) has a free end adapted to contact the second closure means (18) to hold the second closure means (18) in the closed position when the first closure means (17) is in the closed position and to allow the second closure means (18) to open when the first closure means (17) is in the open position; the second closure means (18) being movable along the given axis (A).

Description

The present invention relates to a three-way electrovalve for a fluid supply circuit, particularly for a coffee-making machine.

DE 14 54 228 A describes a device for metered filling of liquids, especially drinks to be dispensed in portions, which is intended in particular for more or less automatically working or self-paying coffee machines or similar beverage preparation devices.

DE 34 14 034 A1 describes a brewing head for espresso coffee machines, in which the infusion is produced by brewing and by making special use of the coffee powder, since the piping system for the hot water supply to the filter holder is provided with an air reservoir in the brewing head, with the piping system alternating with the Hot water inlet connection and the outlet connection is connected.

DE 691 05 242 T2 describes an espresso coffee machine of the type with one or more coffee dispensing units with a chamber provided with a filter to be filled with coffee powder. The espresso coffee machine includes a hot water boiler for heating the water to the coffee brewing temperature, an electric heater located in the coffee dispensing unit or in each coffee dispensing unit and intended to have the correct coffee infusion temperature regardless of the temperature of the water coming from the hot water boiler and valve means for supplying the hot water coming from the hot water boiler to the respective coffee dispensing unit during the infusing step and for releasing the pressure built up in the filter chamber at the end of the infusing step.

EP 0 934 719 A1 describes a method and a device for preparing a drink, in particular espresso coffee, from a predetermined dosage of coffee powder, through which a predetermined quantity of heated water is passed, the water being conveyed from a storage container fed by a pressure pump at a predetermined maximum pressure. The device comprises a preliminary stage in which the dosed quantity of coffee powder is wetted by an initial quantity of heated water at a pressure below the predetermined maximum pressure generated by the pump for a given period of time, followed by a beverage preparation phase during which the heated water is mixed with that generated by the pump generated predetermined maximum pressure is passed through the dosed amount of coffee powder and maintained at this pressure until the preparation of the beverage is complete and it has been dispensed. The preliminary stage in which the measured amount of coffee powder is wetted is accomplished by stopping the supply of cold water supplied to the reservoir by the pump for a predetermined and adjustable period of time and allowing the heated water to flow from the reservoir to the measured amount of coffee under the same pressure - and temperature conditions as inside the reservoir.

U.S.A. 4,998,559 describes a solenoid operated pressure control valve including a solenoid having a central passage, the passage extending axially through the spool. An armature is axially movable within the coil passage to be magnetically attracted to the pole piece when the coil is energized. Fluid pressure at a supply port of the valve biases the armature to its opposite limit of travel when the coil is de-energized. Various forms of valve assemblies are disclosed in which valve heads are positioned at opposite ends of the armature to engage one of the opposite valve seats depending on whether the coil is energized or not. In other arrangements, the armature engages a push rod to release one valve upon energization of the coil while closing a second valve. One valve is biased to its closed position by supply port pressure when the coil is de-energized, with the push rod opening the other valve.

In general, a coffee making machine includes a circuit for supplying hot water that passes through the coffee, which is located within a brewing chamber. The hot water supply circuit includes a supply line connecting a vessel to the brewing chamber; a pressure reducing valve arranged along such supply line; two discharge lines branched from the supply line upstream and downstream of the pressure reducing valve, respectively; and two electrovalves respectively arranged along the two discharge lines. The flow of hot water along the supply line is selectively supplied by a pump located upstream of the boiler.

The following operations can be carried out by means of the two electrovalves placed along the discharge line; pump preparation step, brewing step and discharge step. In more detail, the pump preparation step consists of one Actuating the pump, keeping the electrovalve upstream of the pressure-reducing valve in the open state, and keeping the electrovalve downstream of the pressure-reducing valve in the closed state, to discharge cold water remaining between the boiler and the pressure-reducing valve as a result of the previous discharge.

The brewing step involves keeping the pump working and both electrovalves closed so that the hot water reaches the brewing chamber.

During the discharge step, the pump is stopped while the electrovalve upstream of the pressure reducing valve is kept closed and the electrovalve downstream of the pressure reducing valve is kept open to discharge the pressure in the supply line section between the pressure reducing valve and the brewing chamber to avoid possible dripping to avoid when the coffee is removed.

The circuit described has proved to be particularly effective, but two electrovalves are required to carry out all the steps necessary for the correct operation of the coffee-making machine.

It is an object of the present invention to provide an electrovalve for a fluid supply circuit, in particular for a coffee or similar brewed beverage making machine, which is capable of performing the function of two electrovalves operated independently of each other.

According to the present invention there is provided a three-way electrovalve for a fluid supply circuit, in particular for a coffee or similar beverage making machine, the electrovalve comprising a valve body defining a space or compartment; first and second inlet conduits to the space; a discharge line from the room; a first closure device and a second closure device for interrupting a connection between the space and the discharge line and between the second inlet line and the space; an electromagnetic actuator for controlling at least the position of the first shutter; and a hydraulic device for preventing reverse flow from the first inlet line to the second inlet line.

In accordance with the present invention, the first shutter controlling the discharge line is controlled by the electromagnetic actuator to ensure the brewing step. The extraction or discharge step is ensured by the simultaneous opening of the first and second closure means: in this case no backflow problems can arise through the first inlet line.

The pump preparation step is ensured by simultaneously opening the first inlet line and the discharge line. A possible backflow through the second inlet line is prevented by the hydraulic device.

According to the present invention, such a hydraulic device is constructed as a check valve arranged at the entry of the second line into the compartment. In particular, the check valve is arranged inside the space.

This design or construction prevents backflow into the pump preparation step and ensures that the discharge step is carried out.

According to the present invention, the first closure means is connected to a shaft movable along the given axis, is coupled to the electromagnetic actuator, and has a free end adapted to contact the second closure means for the maintaining the second closure means in the closed position when the first closure means is in the closed position and allowing the second closure means to open when the first closure means is in the open position; the second closure means being movable along the given axis.

This embodiment prevents possible pressure waves from causing the check valve to malfunction during the brewing step.

According to another preferred embodiment of the present invention, the hydraulic device comprises a flow guide for guiding a fluid flow from the first inlet line; wherein the flow guide is designed to create a low or negative pressure at the connection between the second inlet line and the space and a positive pressure at the entrance of the discharge line.

Thereby the non-return valve is not required and the second closure means can be actuated along the given axis in a direction and in a sense coinciding with the first closure means. Therefore, the first and second closure means can be adapted or arranged on the same shaft.

• - 1 eine schematische Ansicht, wobei Teile der Klarheit halber entfernt sind, eines Kreislaufs einer Kaffeeherstellungsmaschine ist, in welcher ein Ventil, welches in Übereinstimmung mit der vorliegenden Erfindung zur Verfügung gestellt wird, installiert ist,
• - 2, 3 und 4 Längsschnittansichten in einem vergrößerten Maßstab, und wobei einige Teile der Klarheit halber entfernt sind, eines Elektroventils sind, welches in Übereinstimmung mit einer ersten Ausführungsform der vorliegenden Erfindung zur Verfügung gestellt ist;
• - 5, 6 und 7 Längsschnittansichten in einem vergrößerten Maßstab, und wobei einige Teile der Klarheit halber entfernt sind, eines Elektroventils sind, welches in Übereinstimmung mit einer zweiten Ausführungsform der vorliegenden Erfindung zur Verfügung gestellt ist; und
• - 8, 9 und 10 Längsschnittansichten in einem vergrößerten Maßstab, und wobei einige Teile der Klarheit halber entfernt sind, eines Elektroventils sind, welches in Übereinstimmung mit einer dritten Ausführungsform der vorliegenden Erfindung zur Verfügung gestellt ist.

For a better understanding of the invention, embodiments thereof will be described below, purely by way of non-limiting example and with reference to the accompanying drawings, in which:

• - 1 Figure 12 is a schematic view, with parts removed for clarity, of a circuit of a coffee making machine in which a valve provided in accordance with the present invention is installed.
• - 2 , 3 and 4 are longitudinal sectional views, on an enlarged scale and with some parts removed for clarity, of an electrovalve provided in accordance with a first embodiment of the present invention;
• - 5 , 6 and 7 are longitudinal sectional views, on an enlarged scale and with some parts removed for clarity, of an electrovalve provided in accordance with a second embodiment of the present invention; and
• - 8th , 9 and 10 are longitudinal sectional views, on an enlarged scale and with some parts removed for clarity, of an electrovalve provided in accordance with a third embodiment of the present invention.

In 1 Reference numeral 1 designates a circuit of a coffee-making machine as a whole.

Although the present invention relates particularly to coffee, it is to be understood that the present invention may also relate to electrovalves used in any type of machine for the production of brewed liquids or beverages in a brewing chamber .

The circuit 1 comprises a supply branch 2, along which a tank 3, a pump 4, a boiler 5, a pressure reducing valve 6, a brewing chamber 7 designed to contain coffee or the like arranged in a sequence; and a discharge channel C.

The circuit 1 also comprises a three-way electrovalve 8 connected to the supply branch 2 by means of two inlet branches 9 and 10, located respectively upstream and downstream of the pressure reducing valve 6, and to the discharge channel C by means of a discharge branch 11.

With reference to 2 until 4 the electrovalve 8 extends along a given axis A and comprises a valve body 12 defining a compartment 13; two inlet ducts 14 and 15 to space 13; a discharge line 16 from space 13; two shut-off devices 17 and 18 for interrupting the communication between the space 13 and the discharge duct 16 and the connection between the inlet duct 15 and the space 13; an electromagnetic actuator 19 for controlling the position of the shutter 17; and a hydraulic device to prevent the reverse flow from the inlet line 14 to the inlet line 15 .

With reference to 1 For example, the inlet lines 14 and 15 are connected to the inlet branches 9 and 10, respectively, while the discharge line 16 is connected to the discharge branch 11.

in the in 2 until 4 In the case shown, the hydraulic device comprises a non-return valve 20, which is arranged at the entry of the second inlet line 15 into the space 13. In particular, the non-return valve 20 is arranged inside the space 13 . In more detail, the check valve 20 comprises the closure device 18, and an elastic member 21 to hold the closure device 18 in the closed position. The check valve 20 preferably includes a spacer 22 disposed within the space 13 to define a shoulder for the resilient member 21. The non-return valve 20 further comprises an elastic ring 23, preferably a helical spring, arranged at the entry of the duct 15 into the space 13, and a sleeve 24 designed to hold the elastic ring 23 in a given position to keep. The sleeve 24 is held in position by the spacer 22 . The closure device 18 comprises a plate which is passed through the spacer 22 and on which the elastic element 21 acts; and a projection which is formed to be inserted into the elastic ring 23 to the ensure hydraulic sealing under the action or bias of the elastic element 21.

In more detail, the two shutters 17 and 18 are aligned along an axis A and are both movable along the axis A to block the outflow of the fluid from the space 13 through the discharge line 16 and the fluid inlet into the space 13 from inlet line 1. The electrovalve 1 comprises a stem 25 selectively movable along the axis A and actuated by the electromagnetic actuator 19 . The closure device 17 is fitted along the shank 25 or is defined in more detail by a radial enlargement of the shank 25 itself.

The valve body 12 consists of two half-shells 26 and 27 which are coupled together with their respective concave areas or cavities facing each other.

Both the inlet ducts 14 and 15 are integral with the half-shell 26, while the discharge duct 16 is integral with the half-shell 27.

According to a variant (not shown in the attached figures), the intake duct 14 is made integral with the half-shell 27 .

In particular, the entry of the inlet 14 is located on the side with respect to the axis A, while the entry of the inlet duct 15 is aligned and centered with the axis A. The half-shell 27 has a zone with a small passage section 28 designed to cooperate with the obturator. The passage cross-section 28 is clearly aligned with axis A and centered. The valve body 12 comprises an elastic ring 29 designed to cooperate with the obturator 17 and secured between a shoulder of the half-shell 27 and the spacer 22 on the passage section 28 .

The electromagnetic actuator 19 and stem 25 are configured so that the shutter 17 is in the normally open position, i.e. the space 13 communicates with the discharge conduit 16 in the absence of electrical power to the electromagnetic actuator 19.

In one use, during the so-called pump priming step, the electrovalve 8 remains in the open position and the fluid is discharged (configuration in 2 ). The process of closing the closure device 17 determines the so-called step of brewing or discharging (configuration in 3 ).

Once the brewing step is over, the pump 4 is stopped and the shutter 17 is opened to exhaust the residual pressure existing in the segment of the circuit 2 downstream of the pressure reducing valve 6 through the non-return valve 20 (configuration in Fig 4 ).

According to the embodiment disclosed in 5 until 7 shown are elements identical or similar to those shown in 2 until 4 are shown are denoted by the same reference numerals. In this case, the electrovalve 8 made in accordance with the present embodiment differs from the previous embodiment in that it comprises a stem 30 which, like the previous stem 25, defines the closure means 17 and has a free end, which is arranged close to the shutter 18 in order to exert a small pressure on the shutter 18 when the electromagnetic actuator 19 is actuated, ie the shutter 17 is in the closed position. In fact, the stem 30 extends almost the entire length of the space 13 and serves the function of preventing an unexpected opening of the check valve 20 during the so-called brewing or dispensing step. When the closure device 17 is in the opening position, the free end of the shaft 30 is spaced from the closure device 18 so as to allow the closure device 18 to be opened.

According to a variant (not shown in the accompanying drawings) the elastic element 21 of the non-return valve 20 is omitted since the actuation of the closing obturator 18 is ensured by the rod 30 at least during the discharge step. During the pump preparation step, the pressure in the space 13 ensures the operation of closing the closure device 18 .

According to the embodiment disclosed in 8th until 10 shown are elements identical or equal to those shown in 2 until 4 shown are denoted by the same reference numerals. In this case, the electrovalve 8 made in accordance with the present invention differs is different from the previous embodiments in that the check valve 20 is omitted and the hydraulic device is defined by a flow guide 31 for guiding the fluid flow from the inlet line 14 . in particular, the flow guide 31 is obtained by arranging the inlet duct 14 inclined relative to the given axis A, and the outlet entrance thereof being directed towards the discharge duct 16. As a result, a low or negative pressure occurs at the inlet of the line 14 and the space 13, while an overpressure occurs at the inlet of the discharge line 16. In a variant (not shown), the flow guide 31 comprises a baffle extending into the space 13, connected to the inlet duct 14 and inclined towards the entrance of the discharge duct 16.

This special design of the inlet line 14 prevents the reverse flow of a fluid through the inlet line 15 during the pump preparation step (configuration in Fig 8th ), even if the inlet line 15 is open. Therefore, the shutter 18 can be operated in unison with the shutter 17 . Therefore, the electrovalve 8 made in accordance with the present embodiment has a stem 32 along which both obturators 17 and 18 are arranged.

The operation of the present embodiment differs from the previous embodiments only during the pump priming step (configuration shown in Fig 8th is shown). In the specific case, during the pump preparation step, both shutters 17 and 18 are placed in the open position and the liquid flow does not enter the inlet line 14 only due to the fluid dynamic effect created by the flow guide 31 in the space 13.

The electrovalve 8 according to the different embodiments has the advantage of performing tasks normally performed by two electrovalves and thus allows to save an electromagnetic actuator. Such an objective is achieved by means of a passive hydraulic device, i.e. one which does not require external control, but which uses the characteristics which the circuit imparts to the fluid, such as pressure and speed, in order to establish preferred paths in the valve body 12 to determine.

Furthermore, the electrovalve 8 is characterized by its structural simplicity and ease of assembly.

It is further apparent that modifications can be made to the present invention without departing from the scope of protection, which is defined in the appended claims.

Accordingly there is provided a three-way electrovalve for a fluid supply circuit 1, in particular for a coffee or similar beverage making machine, comprising a valve body 12 defining a space or compartment 13; first and second inlet conduits 14, 15 to space 13; a discharge line 16 from the space 13; a first shutter 17 and a second shutter 18 for shutting off a connection between the space 13 and the discharge pipe 16 and the connection between the second inlet pipe 15 and the space 13; an electromagnetic actuator 19 for controlling at least the position of the first shutter 17; and a hydraulic device for preventing reverse flow from the first inlet line 14 to the second inlet line 15 .

Claims (7)

Three-way electrovalve for a fluid supply circuit (1), in particular for a coffee or similar beverage making machine, the electrovalve (8) having a valve body (12) defining a compartment (13); a first and a second inlet line (14, 15) to the space (13); a discharge line (16) from the space (13); first closing means (17) and second closing means (18) for interrupting communication between the space (13) and the discharge line (16) and between the second inlet line (15) and the space (13); an electromagnetic actuator (19) for controlling at least the position of the first shutter (17); and a hydraulic device for preventing a reverse flow from the first inlet line (14) to the second inlet line (15), the hydraulic device comprising a check valve (20) which is located at the entrance of the second inlet line (15) placed in the space (13); more specifically the non-return valve (20) is placed inside the space (13), the first closure means (17) being connected to a rod (25, 30) movable along a given axis (A) and to the electromagnetic actuator (19) and wherein the stem (30) has a free end adapted to contact the second closure means (18) to hold the second closure means (18) in the closed position when the first closures means (17) is in the closed position and to allow the second closure means (18) to open when the first closure means (17) is in the open position; the second closure means (18) being movable along the given axis (A). electrovalve after claim 1 , wherein the check valve (20) comprises the second closure device (18). electrovalve after claim 2 wherein the check valve (20) comprises an elastic member (21) to hold the second closure means (18) in the closed position. electrovalve after claim 3 wherein the non-return valve (20) comprises a spacer (22) arranged inside the space (13) to define a shoulder for the elastic member (21). Electrovalve according to any one of the preceding claims, in which the valve body (12) is defined by a first half-shell (26) and a second half-shell (27) which are joined with their respective concave portions facing towards one another. electrovalve after claim 5 wherein the first inlet duct (14) is formed integrally with the first half-shell (26); the discharge duct (16) being formed integrally with the second half-shell (27). electrovalve after claim 5 or 6 wherein the second half-shell (27) has a portion with a narrow flow cross-section (28) and is designed to cooperate with the first closure means (17).

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