Abstract:
Embodiments of the present invention provide improved heating methods for use in coffee makers and other beverage makers that use hot water for various beverages and other purposes. These improvements find particular use on-board aircraft or other passenger transport vehicles, where quick heating and reduced power consumption are particularly desirable and beneficial. Further embodiments also relate to improved water level sensing, improved water reservoirs, and improved carafe features.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application claims the benefit of U.S. Provisional Application Ser. No. 61/699,533, filed Sep. 11, 2012, titled “Coffee Maker Water Heater,” the entire contents of which are hereby incorporated by reference. 
     
    
     FIELD OF THE INVENTION 
       [0002]    Embodiments of the present invention relate generally to improvements for coffee maker heating and find particular use on-board aircraft or other passenger transport vehicles, where quick heating and reduced power consumption are desirable. Embodiments also relate to improved water level sensing, improved water reservoirs, improved carafe features, and improved valve features. 
       BACKGROUND 
       [0003]    Traditional coffee makers either use immersion heating or flow-through heating systems for heating water. For immersion heating in a hot water tank (which may use a pressurized or a non-pressurized tank), water is heated within the tank and then held at the desired temperature until dispensed. Flow-through heating systems generally use a direct heater immersion or heat exchanger in the water path. Sometimes called “demand” or “instant” heating systems, these systems heat water instantly from ambient temperature up to the desired dispensing temperature upon request. Flow-through heating systems are generally desirable for most modern water heating equipment, particularly aircraft equipment, primarily due to weight savings compared with hot water tank systems. The efficiency and compactness of flow-through systems can be advantageous, and these systems also eliminate heat-up and recovery time. 
         [0004]    However, one major disadvantage with traditional flow-through systems is that the power required to effectively heat from ambient up to a desired dispensing temperature (usually near boiling) with adequate dispense flow rates limits the use of these systems to either slow running equipment or to installations that require a high electrical load capacity. The electrical current required to operate flow-through heating systems is typically very high because the systems rely on heating the water with only a single pass through the heater. 
         [0005]    However, reducing power consumption for aircraft equipment (as well as equipment for other passenger transport vehicles) is a desirable goal in the equipment manufacturing business. For example, more and more airlines are seeking to reduce their on-board power consumption in order to be more fuel efficient, cost-effective, and more environmentally friendly, as well as to provide more power to the consumer in-flight entertainment systems that are increasingly used on-board aircraft. One item of equipment that can be improved to pull less power is the coffee maker/hot water heater systems. 
         [0006]    Another problem with some on-board coffee makers is that they can be difficult to clean, particularly the water reservoir area. The present inventors have thus determined ways to design the water reservoir as a removable component that can be cleaned and replaced back into the coffee maker/hot water heater unit. 
       BRIEF SUMMARY 
       [0007]    Embodiments of the present invention thus provide improved heating methods for use in coffee makers and other beverage makers that use hot water for various beverages and other purposes. These improvements find particular use on-board aircraft or other passenger transport vehicles, where quick heating and reduced power consumption are particularly desirable and beneficial. Further embodiments also relate to improved water level sensing, improved water reservoirs, and improved carafe features. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0008]      FIG. 1  shows side schematic view of one embodiment of a coffee maker water heater that uses a flow-through water path recirculation system. 
           [0009]      FIG. 2  shows a side schematic view of a coffee maker water heater that has a water fill system. 
           [0010]      FIG. 3  shows a side schematic view of a coffee maker water heater that has a return line delivering water to a water intake opening. 
           [0011]      FIG. 4  shows a schematic of an electrical rendering of the coffee maker water heater of  FIGS. 2 and 3 . 
           [0012]      FIG. 5  shows a front perspective view of one embodiment of a coffee maker employing a coffee maker water heater and having a carafe with a liquid level viewing window. 
           [0013]      FIG. 6  shows a side perspective view of a coffee maker water heater system. 
           [0014]      FIG. 7  shows an exploded perspective view of a reservoir and its related components. 
           [0015]      FIG. 8  shows a side perspective view of a water fill area on the reservoir. 
           [0016]      FIG. 9  shows a side perspective view of one embodiment of how water may exit the reservoir. 
           [0017]      FIG. 10  shows a side perspective view of one embodiment of a heater assembly. 
           [0018]      FIG. 11  shows a side perspective view of the reservoir in place in the unit housing, with the valves and sensors in place. 
           [0019]      FIG. 12  shows a rear perspective view of the reservoir in place in the unit housing, showing one embodiment for connections of the conduit and a placement of the heater assembly. 
           [0020]      FIG. 13  shows an exploded perspective view of one embodiment of a poppet valve. 
           [0021]      FIG. 14  shows a top perspective view of various valves that control the flow of water through the system. 
       
    
    
     DETAILED DESCRIPTION 
       [0022]    Embodiments of this invention thus improve upon traditional flow-through systems by providing the advantages of flow-through heating (e.g., providing hot water upon demand), without the major disadvantage of requiring such a great power consumption and/or by requiring delivery via a slow flow rate. By recirculating water through a flow-through heater and holding that water within the reservoir at a holding temperature (which is generally, but need not always be, below the desired dispensing temperature), it is possible to almost instantly heat the water to near boiling temperature upon request. As the holding temperature nears the desired dispense temperature, there will be reduced benefits to energy loss to the environment as the temperature delta between reservoir and ambient are increased. However, a higher holding temperature may be required for systems that are auto-filling system for extended continuous dispensing with smaller reservoirs. 
         [0023]    The systems described herein use significantly lower power requirements, but do not require a slow flow rate. This increases the possibilities for flow-through heating and allows for its use on installations with comparatively lower electrical capacities. For example, some smaller aircraft have lower power requirements and capabilities than larger commercials airliners. Additionally, larger airliners may find the systems described herein useful in order to lower the overall power consumption of the coffee maker/water heaters for any number of reasons, including those described above. 
         [0024]      FIG. 1  shows one embodiment of a water heating system  10 . The system includes a reservoir  12  for holding the water to be heated, a flow-through heater assembly  14 , and a pump  16  for moving the water through the system. The system is fluidly connected via various conduits  18 , such as tubing or pipes, which may be any appropriate water flow conduit. The reservoir  12  is initially filled with cold or ambient water, either from the pressurized water system of the aircraft (or vehicle) or from a pre-packaged source, such as a bottled water, or water from a faucet or other source. The embodiment showing use with an external water source is illustrated in  FIG. 1 . The embodiment showing use with water being delivered through the pressurized system of the aircraft (but which may also accept water from an external source) is illustrated in  FIG. 2 . 
         [0025]    As shown in both figures, the reservoir  12  is fluidly connected to an in-line flow through heater assembly  14 . The heater assembly  14  incrementally raises the temperature of the water as it passes through the heater assembly  14 . The heater assembly  14  may be any typical flow-through heater assembly that is currently used for coffee maker water heaters (either for use on-board aircraft or for other uses). By incrementally heating the water in the reservoir  12 , less instant power is needed to heat the water on its final pass through the system, immediately prior to its use. One example of a potential heater assembly is shown in  FIG. 10 . 
         [0026]    A pump  16  is also provided in order to circulate water from the reservoir  12  to the heater  14  and either back to the reservoir  12  or to the appropriate water delivery outlet. The pump may be any typical water pump that is currently used for moving water through aircraft lines or for any other water pump usage. During the warming period (i.e., when water is not needed for dispensing but when the reservoir has been filled to a desired level), the pump routs the water through the conduit  18  to the heater assembly  14  and back to the reservoir  12 . As the water circulates through the heating system, the water temperature in the reservoir rises. This allows the water to be heated to the desired final temperature faster upon the final pass-through the system, and with less power consumption required for that final pass. The temperature of the water in the reservoir is raised (due to the water circulation, water being heated and returned to the reservoir) until the desired holding temperature is reached. The desired holding temperature is generally lower than the boiling temperature desired for the water, and may be any desired temperature, for example, in the range of about 130-170° F. and more specifically, in the range of about 140-160° F., although the temperature of the holding water may be as high as the ultimate use temperature. In one embodiment, the water is held in the range of about 150° F. (which may fluctuate as the number of passes increases or stabilizes), and is then passed through the heater for a final dispense temperature of about 187-198° F., although the final dispense temperature may be about 200° F. if the system is set for uses requiring such higher temperatures. The general goal is to save power by keeping the water at a raised temperature, but not as high of the temperature that is desired upon use. By holding the water slightly below the final use temperature but maintaining it at a warmed level, the water is hot enough that it can achieve the desired temperature rise with one final pass through the heater, but requiring a lower power level than required by traditional flow-through systems and without lowering the desired dispensing flow rate. 
         [0027]    In one embodiment, the system  10  is able to hold the water at the desired holding temperature and then heat the water to the desired dispensing temperature by using about 1300 watts, but the system may be designed to use as few as 500 watts if desired. (As a general matter, the lower the power provided, the lesser the temperature rise per pass of water that can be achieved. Lower power may also increase reservoir heat-up time. Higher power is also possible, however there are reduced benefits to use of the recirculating system once power is increased, depending on the flow rates desired.) 
         [0028]      FIG. 6  shows one embodiment of a coffee maker water heating system  10 . When a user initiates a signal that hot water is desired (e.g., when the coffee maker is activated to brew coffee or when the hot water outlet is activated to dispense hot water for a cup of tea, for example), the pump  16  delivers water through the same heating assembly  14  for a final heating step to bring the water to a raised temperature. This time, however, rather than delivering the water back to the reservoir  12 , the system delivers the water to a dispensing conduit area  20 . Dispensing conduit area  20  is governed by a three-way valve  22 . The three-way valve  22  may be closed to prevent flow of water past the valve, opened to direct water into the reservoir loop, or opened to direct water to one of the desired outlets. The valve  22  may be controlled by an automatic controller that indicates how water should be directed. One example of a potential valve system is illustrated in  FIG. 14 . The controller may have the reservoir option set as the default and cause the valve to switch upon an indication that hot water is needed. When the controller is in the “stand-by” mode, it monitors and maintains temperature in the reservoir and circulates the water through the heater assembly  14  as necessary to accomplish the desired temperature. There are many optional ways that the controller can be programmed, two examples of which are: the pump may be left running and the heater is only turned on/off as needed to maintain the temperature, or the pump may be in a default “off” position and only run when the heater is on. One benefit to leaving the pump running is that more accurate temperature measurements can be made and the control system can be simplified (although a continuously running pump does add to the power consumption of the system, as well as wear on the pump component). More detailed controller logic may be written and developed if desired. 
         [0029]    Immediately preceding the three-way valve  22  in the water flow path is a temperature sensor  24 . This temperature sensor  24  is provided in order to confirm that the water is at the desired temperature prior to being dispensed. It may be related to the valve  22  such that if the water is not at the set temperature, even if the water dispense request has been activated, the water may be re-routed to flow through the water flow loop (i.e. back into the reservoir), rather than dispensed. This may happen when the heater assembly  14  is heating up, which may take a few seconds, and the goal is to prevent water from being dispensed until it is the proper temperature. Once the temperature sensor  24  detects that water is of the desired temperature, the three-way valve  22  opens and allows the water to pass to the dispensing conduit area  20 . 
         [0030]    Referring now to  FIGS. 1-3 , the dispensing conduit area  20  is shown as having two dispensing outlets, although more or fewer outlets may be provided. ( FIG. 6  illustrates a single outlet.) In one embodiment, there is a hot water outlet  26  and a brew outlet  28 . The hot water outlet  26  may be used to dispense hot water for tea, hot cocoa, or for any other use that requires hot/warmed water. The brew outlet  28  may be connected to a beverage maker in order to deliver hot water for brewing coffee, espresso, or any other brewed beverage. The outlets may be governed by one or more valves that allow the dispensing of hot water as desired. The valves may be automatic or manual valves. 
         [0031]    In a first embodiment, the joint at which the water would split between the outlets is governed by a three-way valve  30 . This valve either closes the dispensing conduit area  20  to delivery of water (while the water is being warmed through the loop system or when the system is not in use), causes water to flow toward the hot water outlet  26 , or causes water to flow toward the brew head outlet  28 . In an alternate embodiment, the individual outlets may be governed by their own 2-way valve. For example, in the alternate option shown, the hot water outlet  26  may have a 2-way valve  32  that either causes no flow of water or allows water to flow out the outlet when the water request has been made. The brew head water outlet  28  may have a 2-way valve  34  that either causes no flow of water or allows water to flow out the outlet and to the beverage maker when the water request has been made. (Although both options are shown on the figures, it should be understood that only a single 3-way valve  30  or two separate end valves ( 26 ,  28 ) need be used.) 
         [0032]    Once the desired amount of water has been dispensed, the reservoir  12  maybe automatically replenished via the aircraft potable water system or manually replenished using pre-packaged water or water from a faucet. The embodiment shown in  FIG. 2  illustrates a system  10  that is filled via the pressurized tank of the aircraft via a water fill system  40 . Water fill system  40  may feature a water pipe  42  that directs water from an external water source, such as a potable water tank on-board an aircraft or train or other vehicle, to the reservoir  12 . The water inflow can be directed by a water inlet valve  44 , which is activated when the water level in the reservoir is low and needs to be filled. Water sensors are generally provided that can detect water levels and indicate when a fill step should be activated. (Certain embodiments of water sensors for use in connection with the removable tank option are described below, but any type of appropriate sensor may be used, particularly if the removable tank option is not incorporated into the water flow aspects of the invention.) 
         [0033]    The system  10  may also feature an optional flow meter  36 , which measures water flow through the heating system. This information is used as an input in the system controller to so that the selected amount of hot water is delivered, as well as for equipment diagnostics (e.g., to test pump failure, detect system clogs, and so forth). Additionally, a second temperature sensor  38  may be provided in the flow path of the water. This sensor  38  may be provided in a location so as to measure the temperature of the water as it leaves the reservoir  12 , which can indicate to the system how much the water is being heated after its pass through the heater assembly  14 , can indicate to the system when the water in the reservoir is in the desired range so that the pump can stop circulating water through the system, or for any other number of functions. For example, there will be some heat loss as the water flows through the system, so the temperature sensor  38  can help detect how much heat is being lost per unit time. 
         [0034]    Another feature of the hot water heater system  10  is that the water reservoir  12  may be designed to be removable from the unit to allow the reservoir  12  to be cleaned and/or replaced if necessary. Previous water heating/coffee maker designs have used an unmovable, fixed mounted tank. A fixed tank has the disadvantage that the unit must completely disassembled for cleaning and maintenance of the tank. The removable reservoir embodiment of this invention improves the sanitation and reliability of the equipment by making the reservoir removable and accessible for cleaning, maintenance, and filling directly. The removable reservoir is an optional feature that may be provided with the water heating system  10  described above, or a removable tank may be provided with a traditional immersion or flow-through heating system. 
         [0035]    The removable reservoir embodiment generally provides a reservoir  12  that is insertable and removable from an outer housing  46 . One example of such a reservoir  12  is shown in  FIGS. 7 and 8 . In order to create such a removable reservoir  12 , it is first necessary to provide the water level sensors  48  that are external to the reservoir  12 . Traditional water heating/coffee maker designs use in-tank contact sensors or float systems to detect low and high water levels. These submerged contact level sensors have the disadvantage that they create the need for an electrical or mechanical connection to the tank. The sensors  48  used in the current system are not in contact with the reservoir  12 , but instead, liquid level sensing is conducted by the use of non-contact capacitive sensors  48  used to detect low water level. Sensors  48  are located outside the reservoir  12  with no electrical or mechanical connection to the tank, but they can sense the water levels in the reservoir in order to indicate when water should be added, when water is so low that the water flow process/heating should be stopped, or when the water is high enough that the pressurized water in flow should be stopped. The sensors may activate audible or visual alarms to indicate low water, if desired. The non-contact capacitive sensor(s) are also used to detect high water level. If high water level is detected, the aircraft potable water inlet valve  44  is inactivated (and an indication of a full water level maybe provided to the user, via an audible or visual indicia on the system face). 
         [0036]    One example of such external, non-contact sensors may be capacitive level sensors, and exemplary sensors are manufactured by Gems™ Sensors and Controls. As shown in  FIGS. 1-3 , the sensors  48  are generally positioned with one being near the top of the reservoir and one being near the lower area of the reservoir  12 , but the sensors  48  are associated with the housing  40  into which the reservoir is positioned, and not the reservoir  12  itself. They may be secured to the housing, but positioned so that they directly abut the reservoir when it is positioned. By not having sensors directly connected to the reservoir, there are fewer items to be disconnected and reconnected when the reservoir is moved. 
         [0037]    The reservoir is also connected to water conduits  18  via one or more poppet valves  50 . The one or more poppet valves  50  are positioned at conduit connection areas, such that water is allowed to flow between the reservoir  12  and the conduit  18  when the valve seat is open, but that stops the flow of water when the reservoir  12  is removed from the housing  46 . These valves act much like the valves on a humidifier, which allows the humidifier water basin to be removed, preventing the flow of water out of the basin, so that the basin can be filled and replaced. When the basin is replaced, the poppet valve allows a water flow connection to be re-established. For manual filling, the reservoir  12  is either partially removed (e.g., it can be slid out) or completely removed for filling via an opening or water fill access port  52  in the top, and then returned to the unit for catering. Removal of the reservoir also serves for cleaning if needed. An optional debris screen  53  may be positioned at the access port  52  to prevent debris from entering the reservoir. 
         [0038]      FIGS. 1 and 2  show a first poppet valve  50   a  at the water exit port  54 , where the water exits the reservoir to enter the heating loop, and a second poppet valve  50   b  where the water reenters the reservoir. FIGS.  3  and  7 - 9  show an alternate embodiment in which the second poppet valve is not required because water reenters the reservoir  12  through a return line  56  that branches from the 3-way valve  22  and directs water into the reservoir at water intake opening  58 .  FIG. 7  shows a potential location of a single poppet valve  50 , and  FIG. 9  shows a poppet valve  50  connecting the reservoir  12  to a level sensor  48  that is associated with the unit housing  46 . (However, the poppet valve  50  may be used to connect the reservoir directly to the unit housing  46 , with the level sensor positioned alongside the reservoir once it has been positioned.)  FIG. 3  shows that water can be delivered from the water fill system  40  of the vehicle pressurized tank into the water intake opening  58  as well. 
         [0039]      FIG. 13  illustrates one particular embodiment of a specific poppet valve  50  that has been designed for a removable water reservoir  12 . The valve  50  includes an abutment face  72 , which interfaces with the reservoir and a replaceable filter  74  to prevent heating system contamination. Such a valve may also be useful on other systems that use poppet valves, such as similar reservoirs on humidifiers and other types of coffee makers that have removable reservoirs. An internal spring seat  76  helps ensure that water does not leak when the reservoir is removed. 
         [0040]    The external surface of the reservoir may include a sight gauge  62  integrated into the reservoir  12  for the user to monitor water level. Alternatively, the reservoir may be clear so that easy viewing of the water level is available. The absence of any sensors or heaters within the reservoir, and the use of the external level sensors  48  and poppet valves  50  at the interface allow for easy removal of the reservoir  12 . The design provides all level and temperature sensing positioned in the fluid path—outside the reservoir not within the reservoir. 
         [0041]    The figures also show a manual drain  68 , which can allow the conduits  18  to be completely drained, which is particularly important for systems on-board aircraft, which can be subject to freezing water in any of the system&#39;s lines. 
         [0042]    The figures also show an optional check valve  70 , which may be used to prevent hot water from flowing back into the pump  16  (as shown in  FIGS. 1 and 2 ) or that could be used to prevent water from flowing back into the reservoir prior to passing through the heater assembly  14  (as shown in  FIG. 3 ). 
         [0043]      FIG. 4  illustrates one example of the electrical schematic of the system  10 . The user interface  60  may have a series of input options controlled by buttons, knobs, rotary switches, or any other appropriate interface. The commands are relayed to a controller that directs the power supply, various sensors and fuses, the pumps, and valves. 
         [0044]    Another beneficial feature that may be incorporated into the system  10  is providing a carafe with a sight gauge. Traditional airline coffee pots are made from stainless steel and do not include a sight gauge or water level viewing for the user. This has the disadvantage that the user does not know the quantity of beverage in the pot until s/he removes it from the equipment and looks inside from the top opening of the pot. This has contributed to spills and improper use of the equipment, such as preparing a pot of coffee before emptying the pot from the previous cycle. Accordingly, as shown in  FIG. 5 , one embodiment of the present invention provides a liquid level viewing window  64  on the side of the stainless steel carafe  66 . 
         [0045]    Changes and modifications, additions and deletions may be made to the structures and methods recited above and shown in the drawings without departing from the scope or spirit of the invention and the following claims.