Abstract:
The coffee maker of the present invention includes a housing, a water reservoir disposed in the housing and a shower head in fluid communication with the water reservoir. The coffee maker also include a first heating element for heating water from the water reservoir and being controllable between and ON state and an OFF state, and a second heating element located downstream from the first heating element and being controllable between an ON state and an OFF state. The first and second heating elements are operable in at least a first mode and a second mode, the second mode being different from the first mode.

Description:
FIELD OF THE INVENTION 
     The present invention relates to coffee makers and, more particularly, to a heating system for a coffee maker. 
     BACKGROUND OF THE INVENTION 
     Various coffee makers exist for brewing coffee. For example, known drip-style coffee makers heat water from a water reservoir and transport the heated water to a shower head where it is distributed over ground coffee in a brewing chamber to produce brewed coffee. The brewed coffee exits the brewing chamber and is collected in a brewed coffee container retained on the base of the coffee maker. 
     While existing coffee makers are generally suitable for what is regarded as ordinary performance, there is room for improvement in terms of the quality of the coffee produced. In particular, with known drip-style coffee makers, after the water is heated, and before it enters the shower head, the temperature of the heated water decreases due to heat losses to the surrounding area. As a result, the brewed coffee is often not hot enough to suit many users&#39; preferences. 
     SUMMARY OF THE INVENTION 
     It is an object of the present invention to provide a coffee maker. 
     It is an object of the present invention to provide a coffee maker that produces coffee at a sufficiently high temperature. 
     It is an object of the present invention to provide a coffee maker capable of producing coffee at a variety of temperatures according to a user&#39;s preference. 
     These and other objects are achieved by the present invention. 
     The coffee maker of the present invention includes a housing, a water reservoir disposed in the housing and a shower head in fluid communication with the water reservoir. The coffee maker also include a first heating element for heating water from the water reservoir and being controllable between and ON state and an OFF state, and a second heating element located downstream from the first heating element and being controllable between an ON state and an OFF state. The first and second heating elements are operable in at least a first mode and a second mode, the second mode being different from the first mode. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a cross-sectional view of a coffee maker having a dual heating system in accordance with an embodiment of the present invention. 
         FIG. 2  is a schematic illustration of the dual heating system and brewing cycle of the coffee maker of  FIG. 1 . 
         FIG. 3  is side elevational view of a secondary heater of the dual heating system. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Referring to  FIG. 1 , a coffee maker  10  having a dual heating system is shown. The coffee maker  10  includes a base  12  and a housing  14  connected to the base. As shown therein, the base  12  is adapted to support a brewed coffee container  16  thereon. The housing  14  contains a brewing chamber  18  having an outlet  20  positioned generally above the base  12 . The housing  14  also houses a water reservoir  22  and a water supply conduit  24  extending from the reservoir  22  to a shower head  26  positioned above the brewing chamber  18 . The coffee maker  10  also includes a pump (not shown) for pumping water from the water reservoir  22 , through the supply conduit  24 , and to the shower head  26 , as discussed hereinafter. 
     As further shown in  FIG. 1 , a primary heater  28  is disposed in the base  12 . The primary heater  28  is configured to heat water from the water reservoir  22  during operation. In the preferred embodiment, the primary heater  28  is of the type known in the art, such as a 900-1000 Watt heater, although a heater having a higher or lower power rating may also be utilized without departing from the broader aspects of the present invention. Importantly, the primary heater  28  is disposed in the base so that it can keep coffee in the brewed coffee container  16  hot, in addition to heating the water from the water reservoir  22  during brewing. In connection with this, the base  12  may include a thermal plate that the container  16  sits on, capable of transferring heat from the heater  28  to the container  16 . 
     The coffee maker  10  of the present invention also includes a secondary heater  30  disposed in the housing  14  along the water supply conduit  24 . In the preferred embodiment, the secondary heater  30  is spliced in the water supply conduit  24 . As shown in the schematic illustration of  FIG. 2 , the primary heater  28  and secondary heater  30  are electrically coupled to, and controlled by, a processor  32 , as discussed hereinafter. 
     With reference to  FIG. 3 , the secondary heater  30  is preferably a line heater having an extruded aluminum inner tube  34  encased in an outer wall  36  and having an inlet  38  and an outlet  40 . Electrical power to produce heat is supplied by a heater wire  42  electrically connected to an electrical power source. In the preferred embodiment, the secondary heater  30  is a 150-200 Watt heater, although heaters having different power ratings may also be utilized without departing from the broader aspects of the present invention. 
     Referring back to  FIG. 2 , during operation, water from the water reservoir  22  is pumped through, and heated by, the primary heater  28  in the base  12 . The water then travels through the supply conduit  24  and through the secondary heater  30 , which heats the water once again to restore any heat lost. Once heated by the secondary heater  30 , the water is pumped to the shower head  26 , whereby it is distributed over coffee grounds within the brewing chamber  18 . The heated water passes through the coffee grounds, out of outlet  20 , and collects in brewed coffee container  16 . 
     In connection with the above, the coffee maker  10  is operable in a plurality of modes that are selectable by a user from a control panel (not shown) on the coffee maker. In a first or ‘low’ mode, once brewing is initiated by a user, such as, for example, by depressing an appropriate button on the control panel, only the primary heater  26  is actuated to heat the water from the water reservoir  22 . In the first mode, the secondary heater  30  remains off throughout the brewing process. 
     In a second or ‘hot’ mode, as selected by a user, the processor  32 , according to a control algorithm, controls the primary heater  28  to its on position for the duration of the brewing cycle, and cycles the secondary heater  30  on and off during the brewing cycle to provide additional heat to the water passing therethrough. In the preferred embodiment, the secondary heater  30  is switched on for a predetermined amount of time, then switched off for a predetermined amount of time. Once the brewing cycle is complete, the processor  32  may control both heaters to their respective ‘OFF’ positions, or the primary heater  28  may be maintained in its ‘ON’ position to keep the brewed coffee in the container  16  hot. As will be readily appreciated, by cycling the secondary heater  30  on an off throughout brewing, the coffee brewed will be hotter than coffee brewed under the first or ‘low’ mode. 
     In a third or ‘extra hot’ mode, as selected by a user, the processor  32 , according to a control algorithm, controls both the primary heater  28  and secondary heater  30  to their respective ‘ON’ states throughout the entire brewing cycle. As with the second mode, once the brewing cycle is complete, the processor  32  may control both heaters to their respective ‘OFF’ positions, or the primary heater  28  may be maintained in its ‘ON’ position to keep the brewed coffee in the container  16  hot. As will be readily appreciated, by maintaining both heaters  28 ,  30  in their ‘ON’ states throughout brewing, the coffee brewed will be even hotter than coffee brewed utilizing the second or ‘hot’ mode. 
     Importantly, the secondary heater  30  is controlled by an electro-mechanical means such that the secondary heater  30  may be switched on and off, cycled on an off at a specified frequency, or kept in the on position, with each of these modes resulting in an increase in water temperature at the shower head  26 . In the preferred embodiment, the secondary heater  30  is electrically dependent on the primary heater  28 , such that the secondary heater  30  is only operable when the primary heater  28  is on. 
     Advantageously, the coffee maker of the present invention is capable of brewing coffee having a variety of temperatures, according to a user&#39;s preference, and depending on the amount of heat that is being lost during the brewing cycle. For example, if a lot of heat is being lost for any given reason, a user can simply select the second mode to cycle the secondary heater on and off to provide some additional heat, or select the third mode to raise the water temperature even more. 
     While the above-described embodiments relate particularly to a drip-style coffee maker, the present invention is not so limited in this regard. In particular, the dual heating system of the present invention is applicable to any type of coffee maker or brewed beverage appliance that utilizes hot water to produce a beverage. 
     Although this invention has been shown and described with respect to the detailed embodiments thereof, it will be understood by those of skill in the art that various changes may be made and equivalents may be substituted for elements thereof without departing from the scope of the invention. In addition, modifications may be made to adapt a particular situation or material to the teachings of the invention without departing from the essential scope thereof. Therefore, it is intended that the invention not be limited to the particular embodiments disclosed in the above detailed description, but that the invention will include all embodiments falling within the scope of this disclosure.