METHOD FOR PREPARING HOT WATER OF VARIABLE DISCHARGE TEMPERATURE AND BEVERAGE VENDING MACHINE FOR CONDUCTING THE METHOD

Abstract

A method for preparing hot water of variable discharge temperature in a beverage vending machine, wherein the beverage vending machine contains a hot water generating system comprising a cold water supply line, an electrically heatable boiler, which has a boiler-side cold water inlet that can be connected to the cold water supply line for the supply of cold water from the cold water supply line into the boiler and a boiler-side hot water outlet for the discharge of water from the boiler that is heated to a maximum discharge temperature (ϑ.sub.boiler), as well as a hot water outlet line that is connected in terms of flow to the boiler-side hot water outlet and that can be closed by at least one dispensing valve, by way of which the hot water provided with a specified discharge temperature (ϑ.sub.target, ϑ.sub.target1, ϑ.sub.target2, ϑ.sub.target3, ϑ.sub.target4) for the preparation of a hot beverage can be taken from the hot water outlet line, wherein the cold water supply line can be connected alternatively to the boiler-side cold water inlet or to the boiler-side hot water outlet by way of an electrically actuatable 3/2 way valve, which, for the discharge of hot water, can be loaded with a sequence of electrical pulses, whose pulse duration (τ, τ.sub.1, τ.sub.2, τ.sub.3, τ.sub.4) is selected as a function of the specified discharge temperature (ϑ.sub.target, ϑ.sub.target1, ϑ.sub.target2, ϑ.sub.target3, ϑ.sub.target4) of the hot water.

Claims

1. A method for preparing hot water of variable discharge temperature in a beverage vending machine, wherein the beverage vending machine contains a hot water generating system comprising a cold water supply line, an electrically heatable boiler, which has a boiler-side cold water inlet that can be connected to the cold water supply line for the supply of cold water from the cold water supply line into the boiler and a boiler-side hot water output for the discharge of water from the boiler that is heated to a maximum discharge temperature (ϑ.sub.boiler), as well as a hot water outlet line that is connected in terms of flow to the boiler-side hot water outlet and that can be closed by at least one dispensing valve by way of which the hot water provided with a specified discharge temperature (ϑ.sub.target, ϑ.sub.target1, ϑ.sub.target2, ϑ.sub.target3, ϑ.sub.target4) for the preparation of a hot beverage can be taken from the hot water outlet line, wherein the cold water supply line can be connected alternatively to the boiler-side cold water inlet or to the boiler-side hot water outlet by way of an electrically actuatable 3/2 way valve, which, for the discharge of hot water, can be loaded with a sequence of electrical pulses, whose pulse duration (υ, υ.sub.1, υ.sub.2, υ.sub.3, υ.sub.4) is selected as a function of the specified discharge temperature (ϑ.sub.target, ϑ.sub.target1, ϑ.sub.target2, ϑ.sub.target3, ϑ.sub.target4) of the hot Water.

2. The method according to claim 1, wherein in the base position of the 3/2 way valve, the 3/2 way valve connects the cold water supply line in terms of flow with the boiler-side cold water inlet, and in that when the electrical pulse is applied at the 3/2 way valve, the inlet of the 3/2 valve that is connected to the cold water supply line is connected in terms of flow to the second outlet of the 3/2 way valve for the duration of the electrical pulse, the latter second outlet being connected in terms of flow by way of a T-shaped or Y-shaped mixing tube or a static mixer to the boiler-side hot water outlet.

3. The method according to claim 1, wherein the pulse duration (T) is determined as a function of the discharge temperature (ϑ.sub.target) of the hot water, the temperature (ϑ.sub.supply) of the water in the cold water inlet supplied to the boiler, as well as the temperature (ϑ.sub.boiler) of the water discharged from the hot water outlet of the boiler, according to the following relation: T=T*(ϑ.sub.boiler−ϑ.sub.target)/(ϑ.sub.boiler−ϑ.sub.supply) wherein t is the pulse duration, T is the period duration, ϑ.sub.target is the specified discharge temperature of die water, ϑ.sub.supply is the temperature of the water supplied to the boiler, and ϑ.sub.boiler is the maximum discharge temperature of the water in the boiler.

4. The method according to claim 3, wherein the temperature (ϑ.sub.supply) of the water supplied to the boiler is stored as a fixed value in an electronic memory or is detected via a temperature sensor in the cold water supply line and is taken into consideration in the determination of the pulse duration (T) as a variable quantity.

5. The method according to claim 1, wherein the 3/2 way valve is exclusively loaded with the sequence of electrical pulses if the at least one dispensing valve is opened.

6. The method according to claim 4, wherein at least one first and one second dispensing valve are provided, wherein, when the first dispensing valve is actuated, the 3/2 way valve is loaded with a first sequence of electrical pulses having a first pulse duration (υ.sub.1) for the discharge of hot water having a first discharge temperature (ϑ.sub.target), and when the second dispensing valve is actuated, the 3/2 way valve is loaded with a second sequence of electrical pulses that possess a second pulse duration (τ.sub.2), in order to discharge hot water having a second discharge temperature (ϑ.sub.target2).

7. The method according to claim 6, wherein the pulse durations (τ.sub.1, τ.sub.2) corresponding to the different discharge temperatures (ϑ.sub.target1, ϑ.sub.target2) of the water are determined empirically, in particular by specifying a pulse duration (τ, τ.sub.1, τ.sub.2, τ.sub.3, τ.sub.4) and measuring the discharge temperature (ϑ.sub.target, ϑ.sub.target1, ϑ.sub.target2, ϑ.sub.target3, ϑ.sub.target4) that is set, and are stored in a memory of an electronic control device, and in that when the first or second dispensing valve is actuated, the stored value belonging thereto for the first or second pulse duration (τ.sub.1, τ.sub.2) memory and supplied to the 3/2 way valve.

8. The method according to claim 1, wherein the pulse duration (τ.sub.1, τ.sub.2, τ.sub.3, τ.sub.4) and/or the period duration T is variable during a dispensing process.

9. The method according to claim 8, wherein the pulse duration (τ.sub.1, τ.sub.2, τ.sub.3, τ.sub.4) is shortened at the beginning of a dispensing process in comparison to the end of the same dispensing process in order to compensate for heat losses, and/or in that the period duration (T) is shortened at the beginning of a dispensing process in comparison to the end of the same dispensing process in order to reduce temperature fluctuations of the hot water discharged into a filling container.

10. A beverage vending machine for conducting the method according to claim 1, containing a hot water generating system comprising a cold water supply line, an electrically heatable boiler, which has a boiler-side cold water inlet that can be connected to the cold water supply line for the supply of cold water from the cold water supply line into the boiler and a boiler-side hot water outlet for the discharge of water from the boilerthat has been heated to a maximum discharge temperature (ϑ.sub.boiler), as well as a hot water outlet line connected in terms of flow to the boiler-side hot water outlet, the outlet line being able to be closed by at least one dispensing valve, by way of which the hot water provided with a specified discharge temperature (τ.sub.target) for the preparation of a hot beverage can be taken from the hot water outlet line, wherein the cold water supply line can be connected alternatively in terms of flow to the boiler-side cold water inlet or to the boiler-side hot water outlet by way of an electrically actuated 3/2 way valve, and in that an electronic control device is provided, by which the 3/2 way valve can be loaded with the sequence of electrical pulses for the flow connection of the cold water supply line to the boiler-side hot water outlet, the pulse duration (τ, τ.sub.1, τ.sub.2, τ.sub.3, τ.sub.4) of these pulses being set by the control device corresponding to the Specified discharge temperature (ϑ.sub.target, ϑ.sub.target1, ϑ.sub.target2, ϑ.sub.target3, ϑ.sub.target4) of the hot water.

11. The device according to claim 10, wherein the 3/2 way valve comprises an inlet connected to the cold water supply line as well as a first outlet connected to the boiler-side cold water inlet and a second outlet that is connected in terms of flow to the boiler-side hot water outlet via a T-shaped or Y-shaped mixing tube or a static mixer, wherein the outlet of the T-shaped or Y-shaped mixing tube or the static mixer is connected in terms of flow by way of a line to the at least one dispensing valve.

12. The device according to claim 10, wherein at least one first and one second dispensing valve that can be actuated by the control device are provided, and in that when the first dispensing valve is actuated, the control device loads the 3/2 way valve with a first sequence of electrical pulses that possess a first pulse duration (T.sub.1) for the discharge of hot water having a first discharge temperature (ϑ.sub.target1), and when the second dispensing valve is actuated, the control device loads the 3/2 way valve with a second sequence of electrical pulses that possess a second pulse duration (T.sub.2) for the discharge of hot water having a second discharge temperature (ϑ.sub.target2).

13. The method according to claim 1, wherein in a base position of the 3/2 way valve, the 3/2 way valve connects the cold water supply line in terms of flow with the boiler-side cold water inlet, and in that when an electrical pulse is applied at the 3/2 way valve, the inlet of the 3/2 valve that is connected to the cold water supply line is connected in terms of flow to the boiler-side hot water outlet for the duration of the electrical pulse).

14. The device according to claim 11, wherein at least one first and one second dispensing valve that can be actuated by the control device are provided, and in that when the first dispensing valve is actuated, the control device loads the 3/2 way valve with a first sequence of electrical pulses that possess a first pulse duration (T.sub.1) for the discharge of hot water having a first discharge temperature (ϑ.sub.target1), and when the second dispensing valve is actuated, the control device loads the 3/2 way valve with a second sequence of electrical pulses that possess a second pulse duration (T.sub.2) for the discharge of hot water having a second discharge temperature (ϑ.sub.target2).

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0020] The disclosure will be described below with reference to the drawings on the basis of preferred embodiments. In the drawings:

[0021] FIG. 1 shows a schematic representation of the preferred embodiment of a beverage vending machine according to the disclosure;

[0022] FIG. 2a shows a schematic exemplary signal pattern of an electrical pulse P.sub.2 in the case of a discharge temperature ϑ.sub.target2 of 90° C.;

[0023] FIG. 2b shows a schematic exemplary signal pattern of an electrical pulse P.sub.3 in the case of a discharge temperature ϑ.sub.target3 of 70° C.;

[0024] FIG. 2c shows a schematic exemplary signal pattern of an electrical pulse P.sub.4 in the case of a discharge temperature ϑ.sub.target4 of 60° C.;

[0025] FIG. 3 shows a schematic exemplary signal pattern of a sequence of pulses in which the pulse duration is varied; and

[0026] FIG. 4 shows a schematic exemplary signal pattern of a sequence of pulses in which the period duration is varied.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

[0027] FIG. 1 shows a preferred embodiment of the beverage vending machine 1 for conducting the method according to the disclosure for preparing hot water of variable discharge temperature. This machine contains a hot water generating system 2 that comprises a cold water supply line 4 and an electrically heatable boiler 6. The boiler 6 has a cold water inlet 6a on the boiler side connected to the cold water supply line 4 in order to supply cold water from the cold water supply line 4 into the boiler 6, and a hot water outlet 6b on the boiler side by way of which the heated water is discharged from the boiler 6. To the boiler-side hot water outlet 6b is also connected in terms of flow a hot water outlet line 8, which can be closed by at least one 3/2 way dispensing valve 10a or a dispensing valve 10b, 10c, 10d, by way of which the hot water for preparation of a hot beverage 13 can be taken from the hot water outlet line 8a, 8b, 8c, 8d into the brewing units 11a, 11.sub.b, 11.sub.c or a drinking vessel 11d. The brewing unit 11a is, in particular, an espresso brewing unit. Prior to a dispensing process, cooled water present in the line can be drained via the 3/2 way dispensing valve 10a, since the brewing volume for espresso is small in comparison to conventional coffee. The cold water supply line 4 is connected alternatively to the boiler-side cold water inlet 6a and the boiler-side hot water outlet 6b by way of an electrically actuatable 3/2 way valve 12. In the base position, this 3/2 way valve 12 connects the cold water supply line 4 in terms of flow to the boiler-side cold water inlet 6a via the first outlet 12b of the 3/2 way valve 12, so that when an electrical pulse P is applied at the 3/2 way valve 12, the inlet 12a of the 3/2 valve connected to the cold water supply line 4 is connected in terms of flow to the second outlet 12c at the 3/2 way valve for the duration of the electrical pulse P. The latter second outlet is connected in terms of flow by way of a T-shaped or Y-shaped mixing tube 14 or a static mixer 14 to the boiler-side hot water outlet 6b. In this way, at any point in time, only one flow connection is present between the cold water supply line 4 and the hot water outlet line 8.

[0028] Between the cold water supply line 4 and the inlet 12a of the 3/2 way valve 12 are arranged a through-flow meter 19, which can be employed for determining the quantity of water that is supplied or discharged, and a temperature sensor 18, which can be used for determining the temperature of the water supplied to the inlet 12a of the 3/2 way valve 12. In addition, as shown in FIG. 1, a first spring-loaded check valve 16a can be provided between the cold water supply line 4 and the inlet 12a of the 3/2 way valve 12, in order to prevent a return flow of water into the cold water supply line 4 or into a filter, which is not discussed in more detail, when an overpressure occurs in the hot water generating system 2. Another, second spring-loaded check valve 16b that in this case operates as a draining valve or an overpressure valve may also be connected in terms of flow to the inlet 12a of the 3/2 way valve 12 via a T-branch. The dispensing valves 10a, 10b, 10c, 10d, the 3/2 way valve 12, the temperature sensor 18, as well as the through-flow meter 19 are connected to a control device 20 that contains an electronic memory 20a, in which, in particular, the temperature of the cold water detected by the temperature sensor 18 can be stored.

[0029] During a dispensing process, the control device 20 transmits electrical pulses P, P.sub.1, P.sub.2, P.sub.3, P.sub.4 with the pulse durations τ, τ.sub.1, τ.sub.2, τ.sub.3, τ.sub.4 to the electrically actuatable 3/2 way valve 12. As is shown in FIGS. 2a, 2b and 2c, the pulse duration τ is a function of the discharge temperature ϑ.sub.target of the hot water, wherein in these figures, the temperature of the supplied water ϑ.sub.supply of 20° C. and the maximum discharge temperature of the boiler 6 ϑ.sub.boiler of 100° C. were selected as fixed values, by way of example. The ratio between pulse duration τ and period duration T in this case is determined on the basis of the following formula, wherein additionally, a correction factor can also be provided, by way of which the pulse duration can be reduced or increased as a function of other quantities, such as, for example, the ambient temperature.

υ=T*(ϑ.sub.boiler−ϑ.sub.target)/(ϑ.sub.boiler−ϑ.sub.supply)

[0030] In FIGS. 2a to 2c and the following figures, the signal value 0 represents an opening of the first outlet 12b and thus the base position of the 3/2 way valve 12, and the signal value 1 represents an opening of the second outlet 12c of the 3/2 way valve 12. With a higher discharge temperature, the pulse duration υ is correspondingly small, since only a small quantity of cold water has to be intermixed with the hot water provided in boiler 6. In contrast, the pulse duration υ at a discharge temperature of 60° C. under the selected conditions corresponds to approximately half the period duration, since the desired mixing ratio of hot and cold water amounts to 1:1.

[0031] In FIG. 3, a sequence of pulses P is shown, in which the pulse duration τ is varied over an arbitrarily selected time of a plurality of periods T, as is provided in the preferred embodiment of the method according to the disclosure. At the beginning of the dispensing process, the pulse duration is shorter than toward the end of the dispensing process, which has for a consequence that the temperature of the water discharged at the beginning of the dispensing process is higher than toward the end of the dispensing process.

[0032] A preferred variation of the period duration T is shown in FIG. 4 by way of example. At the beginning of a dispensing process, the period duration is shortened and thus smaller quantities of hot and cold water are thus alternatively required, so that a more rapid equilibration of temperature occurs between them. Toward the end of the dispensing process, the period duration is preferably increased, for example by a factor of 3, in order to reduce wear on the 3/2 way valve 12, whose service life is limited by a maximum number of switching cycles. The period duration can amount to is at the end of a dispensing process.

LIST OF REFERENCE CHARACTERS

[0033] 1 Beverage vending machine [0034] 2 Hot water generating system [0035] 4 Cold water supply line [0036] 6 Boiler [0037] 6a Boiler-side cold water inlet [0038] 6b Boiler-side hot water outlet [0039] 8a,b,c,d Hot water outlet lines to the dispensing valves [0040] 10a 3/2 way dispensing valve [0041] 10b,c,d Dispensing valve [0042] 11a,b,c Brewing unit [0043] 11d Drinking vessel [0044] 12 3/2 way valve [0045] 12a Inlet of the 3/2 way valve [0046] 12b First outlet of the 3/2 way valve [0047] 12c Second outlet of the 3/2 way valve [0048] 13 Hot beverage [0049] 14 T-shaped or Y-shaped mixing tube or static mixer [0050] 16a,b First and second spring-loaded check valve [0051] 18 Temperature sensor [0052] 19 Through-flow meter [0053] 20 Control device [0054] 20a Electronic memory of the control device [0055] ϑ.sub.boiler Maximum discharge temperature of the water in the boiler [0056] ϑ.sub.supply Temperature of the water supplied to the boiler [0057] ϑ.sub.target, ϑ.sub.target1, ϑ.sub.target2, Specified discharge temperature of the water [0058] ϑ.sub.target3, ϑ.sub.target4 [0059] υ, υ.sub.1, υ.sub.2, υ.sub.3, υ.sub.4 Pulse duration [0060] T Period duration [0061] P, P.sub.1, P.sub.2, P.sub.3, P.sub.4 Electrical pulse