Motor-operated metering device

Abstract

A motor-operated metering device (1), in particular as a liquid pump for a coffee machine, having a drive motor (2) and at least one piston (4) which is displaceably mounted in a cylinder barrel (9) and which delimits a variable pump volume (23) with the cylinder barrel (9) and a further opposite delimiting surface (11) and which can be displaced in the piston (4) by the drive motor (2). The piston (4) is coupled to the drive motor (2) directly or indirectly via a coupling element (7) which can be displaced exclusively axially in the cylinder barrel (9) and which passes through at least one through-opening (9') formed as an axial slot in the cylinder barrel (9). The coupling element (7) is connected to at least one threaded flank (6) which is arranged outside the cylinder barrel (9) and is mounted so as to be exclusively axially displaceable with respect to the cylinder barrel (9) and has a threaded section (6') which only partially revolves. Furthermore, the drive motor (2) drives a rotatable ring (21), which revolves around the cylinder barrel (9) and the at least one threaded flank (6) and is fixed axially and has an internal thread (21'') engaged with the threaded section (6'), in order to displace the at least one piston (4) axially.

Description

[0001] F07412 5.11.2025

[0002] TITLE MOTOR-DRIVED DOSING DEVICE

[0003] TECHNICAL AREA

[0004] The present invention relates to a metering device for conveyable substances, in particular liquid substances at room temperature or, for example, powdered substances, such as water or milk, especially in connection with a coffee machine.

[0005] STATE OF THE ART

[0006] State-of-the-art coffee machines operate on different principles. One type is the so-called pressureless coffee machine. In these, water flows from a reservoir into an electrically heated tube. The steam generated in this tube forces the heated water through a riser pipe to a spout, from which the heated water drips into a coffee filter. From this filter, the brewed coffee then flows into a carafe at atmospheric pressure.

[0007] In contrast, espresso machines, for example, operate at a higher pressure within the coffee grounds, such as 15 bar. This is achieved by supplying water from a water reservoir or other water source to an electrically driven pump, which then delivers the water under high pressure through an electrically heated section of a brewing chamber containing the coffee grounds. This brewing chamber generally includes a filter to hold the coffee. To generate the high pressure within the coffee grounds, the brewing chamber is located during operation in a sealed area, which can be referred to as a pressure chamber.

[0008] In another coffee machine, which operates fundamentally differently, the water for brewing the coffee is first transferred from a water reservoir to a heated intermediate container. From this intermediate container, the heated water flows to an electrically driven pump, from which it is fed to a brewing chamber under increased pressure, for example, 2 to 3 bar. Unlike an espresso machine, the coffee is not introduced into the brewing chamber as loose ground coffee, but rather as a coffee pod, that is, in a compacted form surrounded by filter paper, placed in a holder. The holder can be fitted with a cover through which water is supplied. F07412 5.11.2025

[0009] 2

[0010] The coffee pod holder forms a sealed pressure chamber. It serves several functions. Firstly, it provides a sealing surface, creating a pressure chamber. Secondly, it has an outlet opening through which the coffee can flow. Thirdly, the coffee pod is positioned within the holder in such a way that the flow of coffee through it is not obstructed. This type of coffee machine occupies an intermediate position between a conventional pressureless coffee machine and an espresso machine.

[0011] For coffee machines that generate pressure using a pump, it is desirable to ensure the pump demand is as precise and reliable as possible. Additionally, noise levels should be low.

[0012] US 8,733,232 and the parallel EP-A-2196115 relate to a drive for a coffee brewing device, comprising: a first gear with an internal thread, by means of which this first gear is rotatably mounted on an external thread of a guide cylinder, so that the first gear is movable when rotating along a cylinder axis of the guide cylinder; a second gear, which engages with this first gear to drive the first gear along the cylinder axis; a housing in which the first gear is received; a brewing piston, which is coupled to the housing, so that this brewing piston, together with the first gear, is movable along the cylinder axis.The drive comprises a linear guide for guiding the housing, which runs at a distance parallel to the cylinder axis and with which the housing engages in such a way that movement of the housing relative to the linear guide in a direction radial to the cylinder axis is prevented, wherein a rotation axis of the second gear is arranged at a predetermined distance relative to the linear guide.

[0013] Other designs from this area are known from US 11,849,878, US 6,453,800, US 2018 / 073502 and EP 3023638.

[0014] PRESENTATION OF THE INVENTION

[0015] The object of this invention is therefore to provide an improved dosing device, not only as a pump for a coffee machine, but generally for pumpable media, i.e., pumpable media, i.e., also for, e.g., liquid or powdered substances or other liquid substances (including solutions, emulsions, and suspensions), wherein this dosing device enables the most precise possible adjustment of the pumped volume, whereby this accuracy should be guaranteed over as many cycles as possible, and the energy expenditure associated with the pumping process should be as low as possible. Furthermore, the device should preferably allow pumping in both directions. F07412 5.11.2025

[0016] 3

[0017] enable, i.e., be able to pump and suck.

[0018] According to a first aspect of the present invention, in other words, it relates to a metering device according to claim 1.

[0019] Such a metering device (for a pumpable medium), which can be used, for example, as a pump in a coffee machine, i.e., as a liquid pump for a coffee machine, is characterized in particular by the fact that it has a drive motor and at least one piston slidably mounted in a cylinder tube, which, together with the cylinder tube and a further opposing boundary surface, defines a variable pumping volume and which can be moved in the cylinder tube by the drive motor.

[0020] The piston is coupled directly or indirectly to the drive motor via a coupling element that is exclusively axially displaceable in the cylinder tube and passes through at least one through-hole in the cylinder tube designed as an axial elongated hole.

[0021] The coupling element is connected to at least one threaded wing arranged outside the cylinder tube and mounted to be axially displaceable with respect to the cylinder tube, with a threaded section that only partially circumferentially surrounds the cylinder tube.

[0022] In addition, the drive motor drives a rotatable ring, fixed in the axial direction and rotating around the cylinder tube and the at least one threaded wing, with an internal thread engaging with the threaded section, in order to move the at least one piston in the axial direction.

[0023] With this inventive metering device or pump, it is possible for the first time to convey the medium to be metered not only under pressure, but also under vacuum. Furthermore, the inventive embodiment enables a sealing system that is free of lubricants. This is a significant advantage, especially in the food industry. The sealing system that can be used in this way allows, in particular, the continuous metering or conveying of liquids containing swollen substances or insoluble particles or suspended solids.

[0024] For the first time, it is possible to generate an oscillating pressure profile—that is, a rapid change between pressure and vacuum of the water being circulated—during hot or cold coffee preparation, especially in so-called "cold brew." This oscillating pressure profile makes it possible, for the first time, to reproducibly produce either different extraction profiles (e.g., in hot coffee extraction) or significantly faster extractions (e.g., in cold coffee extraction = "cold brew").

[0025] Another advantage of using the pump according to the invention is the possible F07412 5.11.2025

[0026] 4

[0027] Eliminating the need for a flowmeter in beverage preparation: Every commercially available coffee maker requires at least one flowmeter. These flowmeters are inherently inaccurate (depending on the delivery pressure). When dispensing incompressible liquids, such as water during coffee preparation, the inventive dosing device allows the dispensed volume to be precisely and reproducibly proportional to the piston's travel: Depending on the drive type, such as a geared motor or stepper motor, calculating the dispensed liquid with a resolution greater than 0.1 ml is easily possible.

[0028] Another advantage of this dosing device is that, without additional hydraulic components such as proportional valves, a predetermined pressure profile can be applied to the medium to be dosed using the embodiment according to the invention. Pressure profiles, i.e., a change in pressure over time according to a predetermined pattern, play an indispensable role in professional coffee extraction.

[0029] Another significant advantage of using the dosing device according to the invention, particularly in beverage preparation, is the achievable operating pressure: While oscillating armature pumps have become established in the household sector and rotary disc pumps in the professional sector, these prior art pumps generally achieve a maximum continuous operating pressure of 12 bar, with the delivery rate decreasing as the operating pressure increases. The maximum pressure of the pump according to the invention far exceeds this; operating pressures of over 15 bar, or over 30 bar, or even over 32 bar can easily be achieved using stainless steel components. The achievable flow rate is also significantly higher than that of prior art pumps for coffee machines: For example, if a BLDC motor with a rated power of 500 watts is used, a delivery rate of up to 300 liters / hour can be achieved at full operating pressure, depending on the gearbox design.

[0030] With the embodiment according to the invention, it is possible for the first time to provide a piston pump with a minimal overall height, wherein the force is preferably applied to the piston centrally, without the need for additional guides, guide bushings or spindles.

[0031] A first preferred embodiment of such a metering device is characterized in that at least two threaded wings, preferably arranged opposite each other around the circumference, are arranged, each covering an angular range of 20-60° (viewed around the main axis of the cylinder tube), preferably 30-50°.

[0032] This allows for an easy-to-assemble and compact design of the dosing device. F07412 5.11.2025

[0033] 5

[0034] The at least one or a pair of opposing threaded wings are preferably mounted in a stationary guide so as to be displaceable exclusively in the axial direction.

[0035] A pair of opposing threaded wings is particularly preferred when it comes to increased service life of the metering device.

[0036] The piston can be connected to the at least one threaded wing via at least one piston axis arranged transversely to the main axis of the cylinder tube as a coupling element.

[0037] Preferably, two opposing threaded wings are arranged, and the piston axis passes through two opposing elongated holes in the cylinder tube and is connected to the respective threaded wing, preferably via a plug connection in a hole, preferably in a blind hole in the respective threaded wing.

[0038] This achieves a symmetrical force transmission from the threaded wings to the piston.

[0039] Another preferred embodiment of the proposed metering device is characterized in that the piston has a through-opening for a piston axis as a coupling element, preferably two opposing through-openings for such a piston axis.

[0040] The piston can be connected to a piston tube slidably mounted in the cylinder tube, preferably via a threaded connection, and the piston tube can have a through-opening for a piston axis as a coupling element, preferably two opposing through-openings for such a piston axis.

[0041] Preferably, such a metering device is characterized in that two pistons are arranged which are synchronously movable and displaceable in the cylinder tube, and preferably a common coupling element, preferably in the form of a piston axis, can be displaced.

[0042] This embodiment is particularly advantageous in the "cold brew" process, i.e., the cold extraction of coffee: While one piston, in a first movement, introduces the water into the brewing chamber filled with coffee grounds, the second piston simultaneously draws in the resulting extraction mixture. In a second step, the movement of the piston is reversed: The extraction mixture is then passed through the brewing chamber again in the opposite direction: The piston that previously drew in the water now expels the extraction mixture from the first brewing process, while the other piston, which previously drew in the water, F07412 5.11.2025

[0043] 6

[0044] The brewing chamber draws in the doubly extracted mixture. By repeating this process multiple times, multiple extraction can be achieved quickly and easily without significant pressure on the substrate being extracted. This pressureless, multiple extraction in a closed circuit is not limited to coffee: for example, the extraction of herbal preparations, such as teas, tinctures, or other pharmaceutical products, opens up a completely new field of application. The two pistons can be attached at opposite ends to a common piston tube, which is slidably mounted within the cylinder. Preferably, the piston tube has a through-opening for a piston shaft as a coupling element, or preferably two opposing through-openings for such a piston shaft.

[0045] The coupling element is preferably designed in the form of a circular cylindrical piston axis, which has a length that is greater than the outer diameter of the cylinder tube.

[0046] Another preferred embodiment is characterized in that the further boundary surface is designed as a connection base attached to at least one end of the cylinder tube, preferably via a union nut, with a through-opening for supplying or removing the pump medium, in particular a liquid, wherein preferably such a connection base is attached to both ends of the cylinder tube if two pistons are present.

[0047] The ring can have an external axially extending toothing and be driven by a toothed belt from the drive motor, preferably such a ring being rotatably mounted on a stationary guide, and preferably this stationary guide also providing at least partially the sliding guide for the at least one threaded wing in only the axial direction.

[0048] Preferably, the drive motor is a brushless DC motor (BLDC motor), preferably also including a gearbox, with a drive wheel arranged on a shaft of the gearbox that drives the ring, preferably via a toothed belt. This is preferred when high pressures or high flow rates are required.

[0049] If an oscillating pressure profile is desired when using the embodiment according to the invention, a stepper motor is preferably used which - with or without a gearbox - enables a rapid change of direction of the piston.

[0050] The further boundary surface preferably has exclusively a through-opening for the supply or discharge of pump medium, in particular F07412 5.11.2025

[0051] 7

[0052] A fluid is provided, and a valve block, e.g., an arrangement with three ports in the sense of a two-way valve or a two-way valve assembly, is arranged at this through-opening. If two pistons and boundary surfaces on both sides, each with exclusively one through-opening on both sides, are present, preferably a valve block, e.g., an arrangement with three ports in the sense of a two-way valve or a two-way valve assembly, is arranged on each side. A further preferred embodiment of the present invention is characterized in that the drive motor, cylinder tube, a guide for the threaded vanes, and optionally a further retaining ring, as well as optionally a power supply and a control unit for the drive motor, are fixedly attached to a single common pump support plate. Such a pump support plate can be designed in the form of a stamped and formed sheet metal part.

[0053] The at least one or a pair of opposing thread wings are preferably mounted in a stationary guide so as to be displaceable exclusively in the axial direction, in that the guide has a region with a radius increased compared to the other radius of the guide for receiving the respective thread wing by forming a sliding widening channel.

[0054] According to a further aspect of the present invention, this relates to the use of such a dosing device for dosing liquid, convertible into liquid form or solid, preferably powdered substances, in particular liquids, preferably milk and / or water, preferably in a coffee machine or a fully automatic coffee machine.

[0055] The present invention further relates to a valve arrangement or valve block in the form of an arrangement with three inlets, which is particularly advantageous in conjunction with a single-inlet pump and which can be used for both pumping and suction purposes. The proposed valve arrangement can be used in conjunction with the metering device described above, but can also be used independently in conjunction with other metering devices that can both pump and suction. Accordingly, the proposed valve arrangement can also be considered a separate invention independent of the pump described above.

[0056] The valve arrangement is characterized by having a single opening or access point to the metering device, an additional opening serving as an inlet opening (first access point), and a further opening serving as an outlet opening (second access point). No further access points are provided.

[0057] The arrangement is further characterized by the fact that it has two controllable valves F07412 5.11.2025

[0058] 8

[0059] features, i.e., devices that can close and open the passage of conveyed material (typically a liquid), and that one of these controllable valves controls the first access and the other of these controllable valves controls the second access.

[0060] These are preferably electromagnetic valves, and these are preferably controlled differently: one for negative pressure (typically the outlet valve with respect to the pump, for example, to the brewing chamber in a coffee machine) and the other for positive pressure (typically the inlet valve with respect to the pump, for example, for the water supply in a coffee machine). Such electromagnetic valves are preferably characterized in that they have (radially external) coils with which a magnetic field is generated, and preferably additionally a core arranged on the axis of the valve, for example in the form of a soft iron core or made of Permalloy, to reinforce the magnetic field that acts on an axial plunger (also referred to as an armature).This allows for the generation of a higher force, and thus the use of a stronger return spring for the plunger, thereby increasing the closing force of the valve.

[0061] This valve arrangement differs from a 3-way valve in that the inlet and outlet ports can be closed simultaneously. Preferably, the valve arrangement also has at least one sensor, which is preferably located in the area of ​​the single access to the pump or in the distributor area at the first and second access points.

[0062] Preferably, at least one of the following sensors is used: pressure sensor, conductivity sensor, or temperature sensor. Particularly preferably, all three sensors are used; combined sensors are also possible. The temperature sensor is preferably located in the manifold area, and the other two sensors, temperature sensor and conductivity sensor, are located near the line to the pump.

[0063] Particularly preferably, at least one sensor is arranged in the valve assembly such that it is in contact with the medium being conveyed in both operating modes, i.e., both in the pressure phase – the operating mode in which the valve for the negative pressure is closed and the valve for the positive pressure is open – and in the negative phase – the operating mode in which the valve for the negative pressure is open and the valve for the positive pressure is closed. This is particularly advantageous for accurate and rapid temperature measurement. A simple embodiment for such an arrangement is the placement of the corresponding sensor between the two valves, for example in the form of a T-shaped arrangement, with one valve being the pressure side. F07412 5.11.2025

[0064] 9

[0065] and the other valve controls the vacuum side of the two outlets, while the further connection to the metering device according to the invention has no further valve or other device for interrupting the medium flow.

[0066] With this arrangement according to the invention, it is possible for the first time to carry out multiple extractions and to monitor the extraction result using suitable sensors. In the case of cold extraction of coffee, the so-called "cold brew," the extraction result can be controlled and monitored via the conductivity sensor; an optional temperature sensor controls the temperature. In the case of a dosing device according to the invention with only one piston, during the pressure phase the medium is pumped from the piston through the valve arrangement, through the connecting pipe, and through the brewing chamber into a compensation vessel, and during the vacuum phase from this compensation vessel—possibly through the brewing chamber—through the connecting pipe and through the valve block back into the dosing device.An additional pressure sensor in the valve arrangement according to the invention can detect an unexpected problem during extraction, in particular an unexpected blockage in the brewing chamber, i.e., in the chamber where the extraction primarily takes place, even with cold extraction liquids.

[0067] A particularly simple design is possible if a central cable block is provided into which the various sensors can be inserted and, for example, secured with clips, so that their sensor area is adjacent to the cable routing. Preferably, the base body of the valve assembly is manufactured from an injection-molded part.

[0068] Furthermore, the two valves are preferably arranged opposite each other with respect to the feed direction from the pump.

[0069] Preferably, the valve arrangement is designed as a single assembly comprising a single fluid block with corresponding recesses for sensors and valve units, these elements preferably being attachable to the fluid block by clamps. Such a valve arrangement is particularly preferably additionally provided in a separate housing and / or mounted on a single support.

[0070] Further embodiments are specified in the dependent claims.

[0071] BRIEF DESCRIPTION OF THE DRAWINGS

[0072] Preferred embodiments of the invention are described below with reference to the drawings, which serve only for illustration and are not to be interpreted restrictively. The drawings show: F07412 5.11.2025

[0073] 10

[0074] Fig. 1 shows a pump suitable for a coffee machine with a single piston and a variable pumping volume, wherein a) a perspective view from an oblique top is shown, b) a perspective view from an oblique bottom, c) another perspective view from an oblique bottom from the other side, and d) a circuit diagram for such a pump with a pumping volume,

[0075] Fig. 2 shows the pump according to Fig. 1 in a view from below in a), from the side of the power supply in b), in c) a view from the front from the side of the single two-way valve arrangement, in d) a view from the rear, in e) a section perpendicular to the piston axis through the valve arrangement, and the section according to AA in Fig.

[0076] 2c) in f) and an exploded view in g);

[0077] Fig. 3 shows a pump suitable for a coffee machine with two pistons and two pump volumes, wherein in a) a perspective view from an oblique top is shown, in b) a perspective view from an oblique bottom, in c) another perspective view from an oblique bottom from the other side, and in d) a circuit diagram for such a pump with two pump volumes, Fig. 4 shows the pump according to Fig. 3 in a view from below in a), from the side of the power supply in b), from above in c), in section according to BB according to Fig. 3b) in d), a front view from the side of the first two-way valve arrangement in e), a rear view in f), the section according to CC in Fig. 3c) in g), and the section according to AA in Fig. 3d) in h) and an exploded view in i);

[0078] Fig. 5 shows a valve arrangement in perspective views, with a) a view from the side of the pump and b) a view from the opposite side;

[0079] Fig. 6 shows the valve arrangement according to Fig. 5 in various views and sectional representations, wherein a) is a view from the side of the pump connection, b) is a view from the opposite side of the temperature sensor, c) is a view from the side of the pump, d) is a view from the opposite side of the connection plate, e) is a view from the side of the pressure sensor, f) is a section along BB according to e), g) is a view from the side of the conductivity sensor, h) is the section according to CC in d), i) is the section according to AA in g), and k) is an exploded view of the individual parts.

[0080] DESCRIPTION OF PREFERRED EXECUTION FORMS

[0081] In the sense of a first embodiment, a first pump F07412 5.11.2025 is shown in Fig. 1 and Fig. 2.

[0082] 11

[0083] 1 shown in different views and sections, this pump having a single piston 4 and thus a single variable pumping volume 23.

[0084] In a second embodiment, Figs. 3 and 4 show a second pump 1 in different views and sections, wherein this pump has two synchronously movable pistons 4 and thus two asynchronously operated counter-rotating pump volumes 23, 23'.

[0085] In the figures, identical or analogous components are designated by the same reference symbols, which are summarized in the following list of reference symbols.

[0086] In the first embodiment, as can be seen in Fig. 1, the pump 1 is equipped with the motor 2, which, as mentioned, is a brushless DC motor (BLDC motor). The motor 2 drives a toothed belt drive wheel 8 via a gearbox 19. This wheel is attached to a shaft 19' via its through-hole 8" by means of a fastening screw 19". The motor 1, together with the gearbox 19, is attached to a pump mounting plate 13, to which a control board 14 for the pump and a power supply 20 are also attached. A retaining ring 12 and a guide 10 are also attached to the pump mounting plate 13. The cylinder tube 9, in which a piston 4 is slidably mounted, is also fixedly and indirectly attached to the pump mounting plate 13 by the combination of the retaining ring 12 and the guide 10.

[0087] The piston 4 is cup-shaped and can be moved but not rotated within the cylinder tube 9. It has a circumferential radial groove 4' in which a sealing ring or piston seal 4' is inserted, so that the piston 4 is sealed against the cylinder tube 9.

[0088] On the side opposite the pump volume 23, which is bounded by the inner surface of the cylinder tube 9, a front surface 3 of the piston 4 and a connection base 11, the piston 4 has an external thread 4'". The piston 4 is attached to a piston tube 5 via its internal thread 5' by means of this external thread 4'".

[0089] This piston tube 5 is also slidably mounted in the cylinder tube 9. For this purpose, further guide bands 16 are provided in radial grooves on this piston tube 5.

[0090] The piston tube 5 encloses an interior space 5'" and has two opposing through-openings 5" in the region of the end opposite the piston. A piston shaft 7 is guided through these through-openings 5".

[0091] This piston shaft 7 extends at both ends through two opposing elongated holes 9' in the cylinder tube 9, and is with each end in a blind hole 6'", which is provided on the inside 6" of two opposing threaded wings 6, F07412 5.11.2025

[0092] 12

[0093] attached.

[0094] These threaded wings 6 are slidably mounted in the aforementioned guide 10 within extensions 10' provided therein, and can therefore only be displaced axially with respect to this guide 10 and, correspondingly, also with respect to the cylinder tube 9. They are slidably trapped in the extension channels 10' in the radial direction. The threaded wings 6 now have threaded sections 6' on their outer surface, which are also accessible from the outside in the area that is not located in the respective extension channel 10'.

[0095] In this accessible area, a toothed belt pulley 21 with a corresponding circumferential internal thread 21" is provided. This internal thread 21" engages in the threaded sections 6' of the threaded wings 6 in their radial areas. The toothed belt pulley 21 is mounted so as to rotate only within the unit consisting of the guide 10 and the retaining ring 12 and has external teeth 2T on its cylindrical outer surface. These external teeth engage with internal teeth 18' of a flat toothed belt 18, which is driven by the toothed belt drive pulley 8 mentioned above.

[0096] Thus, the movable unit formed from piston 4, piston tube 5, piston axis 7 as a coupling element and from the two opposing threaded wings 6 forms a rigid unit that can only be moved in the axial direction.

[0097] If the toothed belt wheel 21 now rotates due to the action of the drive motor 2, the rotation of the toothed belt wheel 21 is translated into an axial movement or pure translation of this unit by the interaction of its internal thread 21" with the two opposing thread sections 6' of the thread wings 6.

[0098] The movable unit is optimally stable and protected against tilting and jamming by the guide bands 16 and 16' and, through the use of a toothed belt and the two threads 21" and 6', can be controlled extremely precisely, especially when using a brushless DC motor, and thus the pump volume 23 can be changed exactly.

[0099] The pump volume 23 is limited on the side opposite the piston by the aforementioned connection base 11, which is fastened by a union nut 15, which has an internal thread 15' that is screwed onto an external thread 9" of the cylinder tube 9.

[0100] The connection base 11 has a single central through-opening 11" through which liquid can be drawn into or expelled from the pump volume 23. This is accomplished via a connecting pipe 22 and a valve assembly 24, which, as can be seen in Fig. 1 d), is additionally equipped with sensors, in particular a temperature sensor 27, F07412 5.11.2025

[0101] 13

[0102] a pressure sensor 28 and a conductivity sensor 29, but can also be supplemented by other additional sensors.

[0103] Figures 3 and 4 show an analogous embodiment, but here two synchronously operated pistons 4 are arranged in the same cylinder tube 9. They are synchronously operated with respect to their movement in the cylinder tube 2, but with respect to the behavior of the respective pump volumes 23 and 23', the behavior of the pump is asynchronous.

[0104] The two pistons 4 are attached to a common piston tube 5, and this piston tube 5 is driven by the motor 2, as already described in connection with the first embodiment.

[0105] At the end of the cylinder tube 9 opposite the first piston and forming a second pumping volume 23' with the second piston 4, a further connection base 11 is provided. This is equipped with a second valve arrangement 32 and a corresponding outlet, analogous to the opposite connection base 11, so that, as can be seen in particular from the circuit diagram according to Fig. 3 d), the two sides of the pump can each be controlled and monitored via separate valves and their own sensors 27-29.

[0106] In this way, the pump with two pistons can be used with double or continuous pumping capacity, or for two units, for example a coffee machine, in parallel.

[0107] The two valve arrangements 24 and 32 are only discussed cursorily and functionally in connection with the two preceding embodiments. The two valve arrangements 24 and 32 can be identical in construction, and such a possible valve arrangement will now be described in more detail with reference to Figures 5 and 6, both with regard to the individual elements and the operating principle.

[0108] This is a valve arrangement in which the metering device is accessed via a single opening, here referred to as connecting pipe 22.

[0109] The valve arrangement allows this single opening 22 to be selectively connected either to an inlet 25 (typically to a water supply in a coffee machine) and / or an outlet 26 (typically to the brewing chamber in a coffee machine). However, it should be noted that, since the pump can also draw in liquid, the opening designated as outlet 26 can also be used for drawing liquid back out, e.g., from the brewing chamber, and the opening designated as inlet 25 can also be used as an outlet from the pump, for example, during a cleaning process.

[0110] The valve assembly includes a central block, which in particular contains a pipe block F07412 5.11.2025

[0111] 14

[0112] 46 has a connecting pipe 22 in which it is formed, as well as distributors, including an inlet distributor 39 and an outlet distributor 39', these two being for the actual valves. Furthermore, there are corresponding distributors for the temperature sensor 27, the pressure sensor 28 and the conductivity sensor 29.

[0113] The sensors are simply attached to the respective distributor using clamps 34 after being inserted into a corresponding opening in the distributor. The sensors 27-29 each have a first front section, which is located in the respective distributor and is in contact with the piping system within the block, thus transmitting the measurement, and a second rear section with a sensor connection 55. These connections 55 are, for example, routed via cables to a central connection plate 52 and can then be connected, for example, to the central control unit 14 of the pump.

[0114] The block also has the aforementioned entrance 25 and exit 26, which are designed as entry port 49 and exit port 53 respectively.

[0115] The actual valves 30, 31 for the two ports 25 and 26 are two-way valves (non-media-separated valves) and are fundamentally identical in design, but are actuated differently. The valve located on the outlet side does not have to withstand the same high pressures as the valve located on the inlet side (this one is closed when the pump delivers high pressure into the brewing chamber); therefore, the guide is designed differently. The valve seat for the two valves is preferably integrated into the distributor (39, 39'). Distributor 39, distributor 39', and pipe block 46 are particularly preferably formed as a single piece, for example, as an injection-molded plastic part.

[0116] Each of these valves has a soft iron core 37, which can be magnetized by a solenoid coil 33 connected to the aforementioned terminal plate 52. The core material can be soft iron (usually 99% Fe) or Permalloy. Its function is to amplify the magnetic force generated by the coils 33. The soft iron core 37 is securely fastened within a cap 38 in the unit containing the solenoid coil 33 by a locking screw 36. The magnetizable armature 41 is slidably mounted in a housing 40, and the spring 38' is arranged in a central opening within the housing. The spring 38' is abutted at the rear by the cap 38 and at the front by the valve seat 43, which is fixedly enclosed in the armature 41.When the solenoid coils 33 are activated, the magnetic field is amplified by the core 37 and acts on the armature 41, pulling it and thus also the valve seat 43 backward to release the valve. On the side of the valve seat 43, which is preloaded by this compression spring 38', there is a stationary cap 42 with an F07412 5.11.2025.

[0117] 15

[0118] A central passage opening is provided. A ring plenum 48 surrounds this stationary cap 42.

[0119] The aforementioned pipe block 46 (see especially Fig. 6h) has a first section 44, which is arranged axially to the axis of the pump, and a second section 45, which is arranged perpendicular to the first section. In this second section 45, the two sensors 28 and 29 are initially arranged on opposite sides, i.e., the pressure sensor 28 on one side and the conductivity sensor 29 on the other. Further downstream of the pump and in the area of ​​the valves, the temperature sensor 27 is arranged, as it were, at the end face. In this distribution section 54 of the pipe routing within the block, the two valves are connected differently, in a sense, reversed configuration.

[0120] In the case of the inlet-side valve arrangement, as can be seen particularly in the sectional views in Fig. 6 f) and i), there is now a direct connection 47 between the distributor section 54 and the central through-opening in the cap 42 of the valve. This through-opening is closed by the aforementioned valve seat 43 when the valve is closed. If the valve seat 43 is released by being pulled backward together with the armature 41 against the force of the spring 38' by the solenoid coil 33 and the soft iron core 37, fluid can pass through the inlet opening 47 and through the cap 42 and back into the ring plenum 48 through slots in the wall of this cap. From there, as can be seen particularly in Fig. 6 f), fluid can then pass through the inlet nozzle 49 to the inlet 25. Conversely, if the pump is in suction mode and this inlet valve is open, fluid can be drawn into the pump in the reverse direction.

[0121] In contrast, in the case of the outlet-side valve arrangement, there are two outlet channels 50 (located, as it were, above and below the opposite inlet opening 47 of the inlet-side valve). These are connected, as it were, from the rear via the ring plenum 48 and the cap 42 and the aforementioned slots provided therein, to the area behind the valve seat 43. If the valve seat 43 is now retracted from the stop on the cap 42, thus opening the valve, liquid can escape through the central through-opening in the cap 42 into the outlet area 51 of the outlet-side valve, and from there, as can be seen particularly in Fig. 6 f), exit through the outlet nozzle 53 to the outlet 46, for example, to the brewing chamber. Here, too, when the pump is in suction mode and, for example, is to draw liquid back from the brewing chamber, the liquid simply flows in the opposite direction to that shown.

[0122] This valve arrangement allows, in particular in connection with the proposed F07412 5.11.2025

[0123] 16

[0124] The pump, but also generally in connection with other pumps designed for both suction and conveying, provides a very precisely controllable and steerable, and above all, optimally monitored fluid flow.

[0125] REFERENCE MARK LIST

[0126] 1 pump

[0127] 2 Engine

[0128] 3 front surface of 4

[0129] 4 pistons

[0130] 4' circumferential radial groove for sealing ring

[0131] 4" sealing ring, piston seal, of 4

[0132] 4" external thread on 4

[0133] 5 piston tube

[0134] 5' internal thread to 5 for 4"'

[0135] 5" through-hole in 5 for 7

[0136] 5"' Interior of 5

[0137] 6 threaded wings

[0138] 6' threaded section on the outside of 6

[0139] 6" inner surface of 6

[0140] 6"' hole extension to 6" for 7

[0141] 7 Piston axis

[0142] 8 Toothed belt drive wheel

[0143] 8' tooth pitch on 8

[0144] 8" through-hole in 8

[0145] 9 cylinder tube

[0146] 9' axial slot for 7 in 9

[0147] 9" external thread on 9

[0148] 10 Leadership

[0149] 10' expansion channels for 6 in 10

[0150] 11 connection sockets

[0151] 11 ' Exit opening in 11

[0152] 12 retaining rings

[0153] 13 Pump support plate

[0154] 14 Circuit board for controlling the motor

[0155] 15 Union nuts

[0156] 15' Internal thread of 15 F07412 5.11.2025

[0157] 17

[0158] 16 guide belt

[0159] 17 Clamping sleeve

[0160] 18 flat toothed belts

[0161] 18' toothing on the inside of 18

[0162] 19 Gearbox (housing)

[0163] 19' Wave of 19

[0164] 19" mounting screw for timing belt pulley on 19' 20 power supply

[0165] 21 Toothed belt pulley

[0166] 21' External toothing on 21 for 18

[0167] 21" internal thread in 21 for 6'

[0168] 22 Connecting pipe

[0169] 23 Pump volume

[0170] 24 Valve arrangement

[0171] 25 entrances in 24

[0172] 26 Exit from 24 (to brewing chamber)

[0173] 27 Temperature sensor

[0174] 28 Pressure sensor

[0175] 29 Conductivity sensor

[0176] 30 Valve 1

[0177] 31 Valve 2

[0178] 32 second valve arrangement

[0179] 33 Magnetic coil (input side)

[0180] 33' Magnetic coil (output side)

[0181] 34 bracket

[0182] 35 Valve insert

[0183] 36 Locking screw

[0184] 37 Soft iron core

[0185] 38 Cap

[0186] 38' compression spring

[0187] 39 distributors (input side)

[0188] 39' Distributor (output side)

[0189] 40 cases

[0190] 41 anchors

[0191] 42 cap

[0192] 43 Valve seat F07412 5.11.2025

[0193] 18

[0194] 44 first section of the line of 22

[0195] 45 second line section of 22

[0196] 46 line block of 24 / 32

[0197] 47 Inlet opening of inlet-side valve 48 Ring plenum

[0198] 49 entrance tubes

[0199] 50 Outlet channels to outlet-side valve 51 Outlet area of ​​outlet-side valve 52 Connection plate

[0200] 53 outlet nozzles

[0201] 54 Distribution area

[0202] 55 Sensor connection

Claims

F07412 5.11.2025 PATENT CLAIMS 1. Motor-driven dosing device (1), in particular as a liquid pump for a coffee machine, with a drive motor (2) and at least one piston (4) slidably mounted in a cylinder tube (9), which, together with the cylinder tube (9) and a further opposing boundary surface (11), defines a variable pumping volume (23), and which can be displaced in the cylinder tube (9) by the drive motor (2), characterized in that the piston (4) is coupled directly or indirectly to the drive motor (2) via a coupling element (7) which is exclusively axially displaceable in the cylinder tube (9) and which passes through at least one through-hole (9') designed as an axial elongated hole in the cylinder tube (9), wherein the coupling element (7) is connected to at least one threaded wing (6) arranged outside the cylinder tube (9) and mounted to be axially displaceable with respect to the cylinder tube (9) with a threaded section (6') that only partially circumferentially and wherein the drive motor (2) drives a rotatable ring (21) rotating around the cylinder tube (9) and the at least one threaded wing (6) and fixed in the axial direction, with an internal thread (21") engaging with the threaded section (6'), in order to displace the at least one piston (4) in the axial direction.

2. Metering device according to claim 1, characterized in that at least two, preferably circumferentially opposing, threaded wings (6) are arranged, each covering an angular range of 20-60°, preferably 30-50°, and / or that at least one or a pair of opposing threaded wings (6) are mounted in a stationary guide (10) so as to be displaceable exclusively in the axial direction.

3. Metering device according to one of the preceding claims, characterized in that the piston (4) is connected to the at least one threaded wing (6) via at least one piston axis (7) arranged transversely to the main axis of the cylinder tube (9) as a coupling element, wherein preferably two opposing threaded wings (6) are arranged, and the piston axis (7) is connected by two opposing F07412 5.11.2025 20 elongated holes (9') of the cylinder tube (9) pass through and is connected to the respective threaded wing (6), preferably via a plug connection in a hole, preferably in a blind hole (6''') in the respective threaded wing (6).

4. Metering device according to one of the preceding claims, characterized in that the piston (4) has a through-opening for a piston axis (7) as a coupling element, preferably two opposing through-openings for such a piston axis, or that the piston (4) is connected to a piston tube (5) which is slidably mounted in the cylinder tube (9), preferably via a threaded connection, and that the piston tube (5) has a through-opening for a piston axis (7) as a coupling element (7), preferably two opposing through-openings (5'') for such a piston axis (7).

5. Metering device according to one of the preceding claims, characterized in that two pistons (4) are arranged which are synchronously movably mounted in the cylinder tube (9), and preferably a common coupling element, preferably in the form of a piston axis (7), can be displaced, wherein preferably the two pistons (4) are attached at opposite ends to a common piston tube (5) which is slidably mounted in the cylinder tube (9), and further preferably the piston tube (5) has a through-opening for a piston axis as a coupling element (7), preferably two opposite through-openings (5'') for such a piston axis (7).

6. Metering device according to one of the preceding claims, characterized in that the coupling element is designed in the form of a circular cylindrical piston axis (7) which has a length that is greater than the outer diameter of the cylinder tube (9).

7. Metering device according to one of the preceding claims, characterized in that the further limiting surface (11) is designed as a connection base (11) attached to at least one end of the cylinder tube (9), preferably via a union nut (15), with a through-opening (11') for supplying or removing pump medium, in particular a liquid, wherein preferably such a connection base (11) is attached to both ends of the cylinder tube (9) when two pistons (4) are present. F07412 5.11.2025 21 8. Metering device according to one of the preceding claims, characterized in that the ring (21) has an external axially extending toothing (2T) and is driven by a toothed belt (18) from the drive motor (2), wherein preferably such a ring (21) is rotatably mounted on a stationary guide (10), wherein furthermore preferably this stationary guide (10) at least partially simultaneously provides the guide for the at least one threaded wing (6) in the axial direction.

9. Metering device according to one of the preceding claims, characterized in that the drive motor (2) is a brushless direct current motor (BLDC motor), preferably also including a gearbox (19), and a drive wheel (8) is arranged on a shaft of the gearbox (19) which drives the ring (21), preferably via a toothed belt (18).

10. Metering device according to one of the preceding claims, characterized in that the further boundary surface (11) has exclusively a through-opening (11') for supplying or removing pump medium, in particular a liquid, and an arrangement with three access points (24, 32) is arranged at this through-opening, wherein, in the presence of two pistons (4) and boundary surfaces (21) on both sides, each with exclusively one through-opening on both sides, an arrangement with three access points (24, 32) is arranged on each side.

11. Metering device according to one of the preceding claims, characterized in that the drive motor (2), cylinder tube (9) and a guide (10) for the threaded wings (6) and optionally a further retaining ring (12), as well as optionally a power supply (20) and a control (14) for the drive motor (2), are fixedly attached to a single common pump support plate (13).

12. Metering device according to one of the preceding claims, characterized in that the at least one or a pair of opposing threaded wings (6) are mounted in a stationary guide (10) so as to be displaceable exclusively in the axial direction, in that the guide (10) has a region with a radius increased compared to the other radius of the guide (10) for receiving the respective threaded wing (6) by forming an expansion channel (10'). F07412 5.11.2025 22 13. Metering device according to one of the preceding claims, characterized in that, preferably in a connection base (11), only one opening (11') is provided for supplying or discharging pump medium, in particular a liquid, and a valve arrangement (24) is arranged at this through-opening, wherein, in the presence of at least one piston (4) and at least one boundary surface (11) with at least one through-opening on the respective boundary surface (11), a valve arrangement (24, 32) is arranged, and wherein the valve arrangement (24, 32) has an opening (25) as a first access and a further opening (26) as a second access, and no further accesses are provided, and that it has two controllable valves (30, 31) that can close and open the passage of pump medium.and that one of these controllable valves controls the first access and the other of these controllable valves controls the second access, and wherein the valve arrangement (24) preferably additionally has at least one sensor, in particular preferably at least one sensor selected from the group: temperature sensor, pressure sensor, conductivity sensor, in particular preferably all three sensors.

14. Use of a dosing device according to one of the preceding claims for dosing liquid, convertible into liquid form or solid, preferably powdered substances, in particular liquids, preferably milk and / or water, preferably in a coffee machine or a fully automatic coffee machine.

15. Coffee machine, in particular a fully automatic coffee machine with a dosing device according to one of the preceding claims, in particular for transporting water, wherein this water can be supplied cold or already heated.

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