HOT FLUID PREPARATION UNIT FOR A FULLY AUTOMATIC COFFEE MACHINE

• US 20150250355A1
• Filed: 03/03/2015
• Published: 09/10/2015
• Est. Priority Date: 03/04/2014
• Status: Active Grant

• Current Assignee: JURA Elektroapparate AG
• Original Assignee: JURA Elektroapparate AG
• Inventors: Reyhanloo, Shahryar, Kao, Ted
• Granted Patent: US 9,826,858 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: A47J 31/54 Water boiling vessels in beverage making machines
• CPC Class Codes: A47J 31/545 Control or safety devices
• CPC Class Codes: A47J 31/56 having water-level controls; having temperature controls

Abstract

A hot fluid preparation unit for a fully automatic coffee machine is specified. With the goal of reducing the heating-up time of a fluid, the solution according to the invention provides that the hot fluid preparation unit has a temperature control device, a fluid heating arrangement, a rectifier circuit and a power semiconductor switching device. The rectifier circuit is connected at an input of the rectifier circuit to an AC voltage supply and at an output of the rectifier circuit, via the power semiconductor switching device, to the fluid heating arrangement. The power semiconductor switching device is designed in a controllable manner such that it selectively switches through the output of the rectifier circuit to the fluid heating arrangement. The temperature control device is configured to control the power semiconductor switching device in a pulsed manner, in order thus to perform a temperature adjustment.

Claims

1. A hot fluid preparation unit for a fully automatic coffee machine, comprising:

a temperature control device;

a fluid heating arrangement,

a rectifier circuit; and

power semiconductor switching device,

wherein the rectifier circuit is connected at an input of the rectifier circuit to an AC voltage supply and at an output of the rectifier circuit via the power semiconductor switching device to the fluid heating arrangement, wherein the power semiconductor switching device is designed to be controllable in such a manner that it selectively switches the output of the rectifier circuit through to the fluid heating arrangement, and wherein the temperature control device is designed to carry out a control of the power semiconductor switching device in a pulsed manner, in order thus to provide temperature control.

2. The hot fluid preparation unit according to claim 1, wherein the temperature control device is designed to vary the ratio of pulse duration to pulse interval of pulses provided for the control of the power semiconductor switching device.

3. The hot fluid preparation unit according to claim 1, wherein the fluid heating arrangement is designed, in accordance with the control of the power semiconductor switching device, to heat up drinking water supplied at an input of the fluid heating arrangement to a water temperature suitable for carrying out a coffee brewing process, or to heat up drinking water supplied at the input of the fluid heating arrangement to a useful steam temperature, and in each case to provide it at an output of the fluid heating arrangement.

4. The hot fluid preparation unit according to claim 3, wherein the fluid heating arrangement is designed to vary the ratio of pulse duration to pulse interval when heating the supplied drinking water, in order to regulate the thermal power of the fluid heating arrangement in a substantially continuous manner.

5. The hot fluid preparation unit according to claim 1, wherein the fluid heating arrangement is a thermoblock with a rated power of 2 kW, preferably of approximately 2.8 kW.

6. The hot fluid preparation unit according to claim 1, wherein the temperature control device is designed to adjust the ratio of pulse duration to pulse interval such that the fluid heating arrangement is operated in a medium power range, preferably approximately 1.4 kW if the target fluid temperature is about 100°

C., and that the temperature control device is designed to adjust the ratio of pulse duration to pulse interval such that the fluid heating arrangement is operated in its rated power range, preferably approximately 2.8 kW, if the target fluid temperature lies in the steam range, advantageously in the region of approximately 160°

C.

7. The hot fluid preparation unit according to claim 1, wherein the hot fluid preparation unit additionally comprises a temperature sensor for sensing the fluid temperature in the fluid heating arrangement or at the output thereof, and wherein the temperature control device is configured to vary the ratio of pulse duration to pulse interval such that a target fluid temperature which is, or is enabled to be, specified in advance is attained at the output of the fluid heating arrangement.

8. The hot fluid preparation unit according to claim 1, wherein the power semiconductor switching device is implemented as a MOSFET, preferably as a power MOSFET.

14. A use of the hot fluid preparation unit according to claim 1 in a fully automatic coffee machine, wherein the fully automatic coffee machine comprises a flow control device for driving an automatic or semi-automatic hot beverage preparation process, and wherein the flow control device assumes the task of specifying the target fluid temperature for the temperature control device in accordance with the temporal sequence of the hot beverage preparation process.

15. The use according to claim 14, wherein the temperature control device controls the fluid heating arrangement during a standby period (T_B) of the fully automatic coffee machine in such a manner that its thermal power amounts to zero throughout.

9. A method for operating a fully automatic coffee machine, wherein to prepare a hot fluid the fully automatic coffee machine comprises at least one hot fluid preparation unit, which in turn comprises:

a temperature control device;

a fluid heating arrangement,

a rectifier circuit; and

a power semiconductor switching device,

wherein the rectifier circuit is connected at an input of the rectifier circuit to an AC voltage supply and an output of the rectifier circuit via the power semiconductor switching device to the fluid heating arrangement, wherein the power semiconductor switching device is designed to be controllable in such a manner that it selectively switches the output of the rectifier circuit through to the fluid heating arrangement, and wherein the temperature control device is designed to carry out a control of the power semiconductor switching device in a pulsed manner, wherein the method comprises;

determining a process-related parameter for a hot beverage preparation to be carried out;

varying of the ratio of pulse duration to pulse interval of pulses provided for the control of the power semiconductor switching device in accordance with the process-related parameter, in order to adjust an associated thermal power (P_TH) of the fluid heating arrangement.

10. The method according to claim 9, wherein the process-related parameter specifies whether hot water or steam is to be dispensed and/or wherein the process-related parameter specifies at what temperature the hot water or the steam is to be dispensed.

11. The method according to claim 10, wherein the ratio of pulse duration to pulse interval is modified when dispensing hot water or steam, in order to vary the thermal power of the fluid heating arrangement in a substantially continuous manner.

12. The method according to claim 9, wherein the method additionally comprises:

determining the fluid temperature that is to be provided at the output of the fluid heating arrangement,

and wherein the process-related parameter specifies whether or not the fluid temperature falls below a process-related target fluid temperature for the hot beverage preparation to be carried out by more than a specified or specifiable value.

13. The method according to claim 9, wherein the temperature control device controls the fluid heating arrangement during a standby period (T_B) of the fully automatic coffee machine in such a manner that its thermal power amounts to zero throughout.