Pump and heating method and arrangement for coffee brewing

Abstract

A method and system for brewing coffee that allows for control of the temperature of the water as it hits ground coffee and that is adapted for changes in the environment. A coffee machine may include: a water reservoir, a pump, a heating element, a filter holder, a temperature sensor, and a control element. Instead of using boiling water to drive the flow of water from the water container to the filter holder, which method relates the outlet temperature to the water's boiling point, which, in turn, is dependent on altitude and other factors, the coffee machine described herein uses a pump to deliver water from the water container to the heating element and on to the filter holder. The coffee machine also includes a heating element that is not susceptible to frost damage, which may include a silicone layer sandwiched between two metal components, such as aluminum blocks.

What is claimed is: 
     
         1 . A method for brewing coffee in a coffee machine including a water reservoir, a heating element, a water pump, and a coffee flask with a filter holder positioned above the coffee flask, the method comprising:
 measuring an ambient temperature in the coffee machine with a temperature sensor;   estimating a temperature reduction of water from the heating element to the filter holder using a predefined model;   providing power to the heating element, the heating element heating water from the water tank, the water then passing from the heating element through a conduit to the filter holder;   when a temperature of said heating element reaches a first predefined temperature, activating the water pump for a first time interval until the heating element is filled with water;   disabling the water pump for a second time interval until the temperature of the water in the heating element has reached a second predefined temperature;   estimating a throughput level in the heating element that provides a predefined output temperature of the water when the water contacts ground coffee beans contained in the filter holder, the throughput level being based on the estimated temperature reduction and measured ambient temperature; and   activating the water pump with a voltage level that provides the estimated throughput level.   
     
     
         2 . The method according to  claim 1 , further comprising:
 monitoring an actual temperature reduction, and if the actual temperature reduction differs significantly from the estimated temperature reduction, then:   estimating a modified throughput level in the heating element that provides the predefined output temperature of the water when the water contacts the ground coffee beans contained in the filter holder using an adjusted estimated temperature reduction based on an adjusted predefined model and the measured ambient temperature; and   altering the pump voltage level to a different voltage level that provides the estimated modified throughput level.   
     
     
         3 . The method according to  claim 1 , wherein the second predefined temperature is equal to the first predefined temperature. 
     
     
         4 . The method according to  claim 1 , wherein the predefined output temperature is in the range of between approximately 90° C. and approximately 96° C. 
     
     
         5 . The method according to  claim 1 , wherein the second time interval is equal to the first time interval. 
     
     
         6 . The method according to  claim 1 , wherein the first time interval is approximately two seconds. 
     
     
         7 . The method according to  claim 1 , wherein the heating element includes one or more metal elements and one or more silicone layers in thermal contact with the one or more metal elements, the one or more silicone layers defining one or more channels through the thermal element from which the water flows into the conduit. 
     
     
         8 . The method according to  claim 7 , wherein the one or more metal elements consists of two metal elements, the one or more silicone layers being positioned between the two metal elements. 
     
     
         9 . The method according to  claim 8 , wherein the two metal elements are composed of aluminum. 
     
     
         10 . The method of  claim 1 , wherein the filter holder includes a rotatable ring for aroma control. 
     
     
         11 . The method of  claim 1 , wherein the coffee machine further includes a water outlet for dispensing water onto the ground coffee contained in the filter holder. 
     
     
         12 . A machine for brewing coffee, the machine comprising:
 a water reservoir;   a pump and a heating element in fluid communication with the water reservoir;   a temperature sensor; and   a control element in communication with the pump, the temperature sensor, and the heating element.   
     
     
         13 . The machine of  claim 12 , wherein the temperature sensor is configured to measure an ambient temperature in the machine and measure a temperature of the heating element. 
     
     
         14 . The machine of  claim 13 , further comprising a filter holder in fluid communication with the heating element. 
     
     
         15 . The machine of  claim 14 , wherein the control element is programmed to:
 estimate a reduction in a temperature of water within the heating element and a temperature of the water as it is delivered to the filter holder from the heating element;   activate the pump for a first period of time to deliver water from the water reservoir to the heating element when the temperature sensor measures a temperature of the heating element that is equal to or greater than a first predefined temperature; and   disable the pump for a second period of time until the temperature sensor measures a temperature of water within the heating element that is equal to or greater than a second predefined temperature.   
     
     
         16 . The machine of  claim 15 , wherein the control element is further programmed to:
 estimate a throughput level in the heating element that provides a predefined output temperature of the water when the water is delivered to the filter holder from the heating element, the throughput level being based at least in part on the estimated reduction in temperature and measured ambient temperature; and   activate the pump with a voltage level that provides the estimated throughput level.   
     
     
         17 . The machine of  claim 16 , wherein the control element is further programmed to:
 monitor an actual reduction in the temperature of water within the heating element and the temperature of the water as it is delivered to the filter holder from the heating element, the actual reduction based at least in part on temperature measurements received from the temperature sensor;   estimate a modified throughout put level in the heating element that provides the predefined output temperature of the water when the water is delivered to the filter holder using an adjusted estimated temperature reduction based on an adjusted predefined model and the measured ambient temperature; and   adjust the pump voltage level to a different voltage level that provides the estimated throughput level.   
     
     
         18 . The machine of  claim 15 , wherein the predefined output temperature is between approximately 90° C. and approximately 96° C. 
     
     
         19 . The machine of  claim 12 , wherein the heating element includes:
 a first aluminum element and a second aluminum element;   one or more silicone layers between and in thermal contact with the first aluminum element and the second aluminum element, the one or more silicone layers defining one or more channels through the thermal element that are in fluid communication with the water reservoir.   
     
     
         20 . A machine for brewing coffee, the machine comprising:
 a water reservoir;   a pump and a heating element in fluid communication with the water reservoir;   a filter holder in fluid communication with the heating element;   a temperature sensor; and   a control element in communication with the pump, the temperature sensor, and the heating element, the control element being programmed to:
 estimate a reduction in a temperature of water within the heating element and a temperature of the water as it is delivered to the filter holder from the heating element; 
 activate the pump for a first period of time to deliver water from the water reservoir to the heating element when the temperature sensor measures a temperature of the heating element that is equal to or greater than a first predefined temperature; 
 disable the pump for a second period of time until the temperature sensor measures a temperature of the heating element that is equal to or greater than a second predefined temperature; 
 estimate a throughput level in the heating element that provides a predefined output temperature of the water when the water is delivered to the filter holder from the heating element, the throughput level being based at least in part on the estimated reduction in temperature and measured ambient temperature; and 
 activate the pump with a voltage level that provides the estimated throughput level.