Abstract:
A coffee maker assembly particularly suitable for aircraft use delivers hot coffee into a decanter that can be removed from the assembly to serve the coffee to passengers and crew inside an aircraft cabin. The assembly includes an electronically controlled solenoid valve that controls the delivery of water from a reservoir into a coil heater. Electronic circuitry in the system controls the assembly&#39;s operation and provides various indications to a user of the system. Various automatic valves, couplings, and other features ensure safe and reliable operation with minimal maintenance.

Description:
BACKGROUND OF THE INVENTION 
     The invention relates generally to electrical equipment for use on aircraft, and more particularly, to electrical coffee maker systems for use in aircraft galleys. 
     Passenger aircraft fly routinely across oceans and continents. Passengers and crew spend several hours and more on board those aircraft. Passenger and crew comfort and efficiency depend to a great degree on the availability of hot food and beverages in flight, and passenger aircraft routinely include galleys and similar preparation areas for such food and beverages. 
     Many people enjoy hot coffee; for some it&#39;s a near necessity. Aircraft galleys have thus for some time included coffee maker systems designed to brew and dispense coffee to passengers and crew. Such existing coffee maker systems are typically less than ideal, though, for a variety of reasons. 
     Many such prior art systems are little changed from systems used on the ground in fixed installations. Brewed coffee drips into an open-topped pot placed under a dispenser. Such pots are sometimes not fixed in place, though, which creates an obvious spillage hazard, e.g., if someone bumps against the pot in the crowded aircraft galley or if the aircraft encounters turbulence or other motions that might cause coffee to spill out of the pot. 
     Some such open pot systems include apparatus for fixing their coffee pots in place while the coffee is being dispensed into them. When the coffee is in the pot, the pot can then be removed from the coffee maker so that the coffee can be served out to the passengers and crew. Such open pot systems are still less than ideal, though, because coffee can spill out of the pots&#39; open tops either while the pots are in place in the coffee maker or while the pots are being moved around the cabin. 
     Other systems for brewing coffee on board aircraft include sealed pressure vessels or the like. Water is heated inside these pressure vessels and dispensed as coffee into pots for service. Such pressure vessel systems tend to be heavy and bulky, though, which is particularly disadvantageous on board aircraft, where any added weight leads directly to increased fuel consumption and thereby to increased operating costs. Pressure vessel systems can also present explosion hazards, and reliable mechanisms must be provided to vent pressure safely to prevent overpressure conditions inside the pressure vessels. Pressure vessel systems thus tend to be heavy and complex, expensive to operate, and difficult to maintain. 
     Other known systems require frequent and difficult maintenance. This makes such systems unreliable, and much time and expense can be involved in keeping these systems in reliable operation. A poorly designed or maintained system can ground even a multi-engine jumbo jet while one of its coffee makers is being serviced. This is a very expensive way to serve coffee. 
     It would be desirable, therefore, if new coffee maker systems could be developed in which coffee is dispensed into serving pots or the like through closed lids with very limited openings. Those pots should also be fixed into the coffee makers for added safety. Such systems, should, if possible, avoid the weight, expense, and reliability problems of known pressure vessel systems. A new onboard coffee maker system should be reliable and easy to maintain without taking airplanes out of service for frequent and extended maintenance. Lastly, a new aircraft coffee maker should be easy to use, and should produce good coffee the people will enjoy drinking. This document describes novel coffee maker assemblies that provide these and other advantages. 
     SUMMARY OF THE INVENTION 
     The invention provides a coffee maker assembly particularly suitable for use in aircraft galleys. A particular embodiment of the invention includes a flow control valve for controlling the flow of water out of a water supply reservoir and into a heater element. Hot water is received from the heater element and directed via a conduit into contact with ground coffee. Hot liquid coffee is produced thereby, and directed into a receptacle configured to receive and hold the coffee until it can be served. In a particular preferred embodiment the flow control valve is an electrically controlled solenoid valve controlled by electronic signals from a central system electrical controller. 
     Water filters can be provided in conduits between the flow control valve and other elements of the system, to protect the flow control valve against particles suspended in the water flowing in the system. 
     In preferred embodiments, the receptacle configured to receive and hold the hot liquid coffee is a decanter that is configured to be received and releasably held by structure of the assembly, so that the decanter is held securely and is thus less likely to spill inside the aircraft. 
     In a particular preferred embodiment, first and second capacitive elements are mounted to a lid the closes the decanter. These elements are coupled to electrical circuitry operable to detect a change in capacitance between the first and second capacitive elements. This occurs when the coffee reaches a predetermined level inside the decanter, at which point the system&#39;s electronic controller closes the flow control valve to end delivery of hot water through the system and coffee into the decanter. 
     A particular decanter receives coffee through a small opening in its lid. This lid includes an anti-spill valve which operates to close the lid opening when the decanter is tipped or the coffee reaches a level near the top of the decanter. This occurs when a floatable valve member moves or floats into contact with a valve seat fixed with respect to the lid&#39;s opening. 
     Methods are provided for monitoring water temperatures at points upstream and downstream of the heater element and a heater element temperature at a point some distance along the heater&#39;s flow path. The flow of water and the operation of the system can be controlled in response to these measured temperatures. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a perspective view of a coffee maker assembly according to the invention. 
         FIG. 2  is a perspective view of a coffee decanter and lid assembly for use in the coffee maker assembly of  FIG. 1 . 
         FIG. 3  is an exploded view showing the major components of the coffee maker assembly of  FIG. 1 . 
         FIG. 4  is a cut-away view of the coffee maker assembly of  FIGS. 1-3 . 
         FIG. 5  is a schematic plumbing diagram illustrating the flow of water and coffee through the coffee maker assembly of  FIGS. 1-4 . 
         FIG. 6  is a schematic diagram of the electrical system of the coffee maker assembly of  FIGS. 1-5 . 
         FIG. 7  is a perspective view of a lid suitable for use with the decanter of  FIG. 2 . 
         FIG. 8  is a cut-away view of the decanter and lid assembly of  FIG. 2 . 
         FIG. 9  is a perspective view of a coffee brew tray for use in the coffee maker assembly of  FIGS. 1-8 . 
         FIG. 10  is a perspective view of an alternative coffee maker assembly. 
         FIG. 11  is a cut-away view showing interior structures of the alternate embodiment of  FIG. 10 . 
         FIG. 12  is a side section view of the top of a decanter in place in the coffee maker assembly. 
         FIG. 13  is a side section view generally similar to that of  FIG. 12 , except that the decanter has been removed from the assembly. 
         FIG. 14  is a side section view showing the assembly with the decanter in place but the brew tray partially removed. 
         FIG. 15  shows details of the coffee maker&#39;s control/indicator panel. 
     
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       FIG. 1  is a perspective view illustrating a coffee maker assembly  5  that embodies the invention. The coffee maker assembly includes a coffee maker body assembly  10 , which may be located, for example, inside an aircraft galley. A decanter  12  can be suspended from the coffee maker body assembly to receive hot coffee from the coffee maker and to hold it for later service to passengers and crew inside the aircraft. The coffee maker&#39;s operations are controlled by a control/indicator panel  13  on the front of the coffee maker body assembly. 
       FIG. 2  shows the decanter  12  alone. The decanter includes a container body  15 , which receives and holds the coffee. A decanter handle  18  is attached to one side of the container body, with a pour spout  20  at the side opposite the handle. A decanter lid  23  closes an opening in the top of the decanter body. 
     The decanter can be one of a variety of commercially available, industry-standard in-flight service decanters. As will be described further below, a custom lid is applied to the decanter. The lid serves as the mounting element and interface between the decanter and the rest of the coffee maker, so that any of a variety of decanters can be used, so long as an appropriate lid is developed and fitted to it. 
       FIG. 3  is an exploded view illustrating the major components of the coffee maker assembly  5 . In particular, the coffee maker body assembly  10  includes a coffee maker rail  25 , a control assembly  28 , and a brew tray assembly  30 . The coffee maker rail  25  mounts more or less permanently (i.e., tools are required to remove it) to a wall or similar structure inside the aircraft&#39;s galley, the control assembly  28  is received over and supported by the rail, and the brew tray assembly  30  slides into the control assembly. 
     Such a configuration is advantageous because it allows the working elements of the assembly, i.e., the control, indicator, and power circuitry and most of the fluid valves and internal plumbing, to be removed from the aircraft by simply removing the control assembly  28  from the coffee maker rail  25  (which can remain fixed inside the galley). A new control assembly can then be installed over the same rail. This allows for quick coffee maker changes (for routine maintenance or repair, for example) so that a multi-million dollar aircraft need never be grounded while one of its coffee makers is repaired. 
       FIG. 4  is a section view illustrating the major internal components of the coffee maker assembly  5 . In particular, the coffee maker body assembly  10  houses a helical water flow coil  33 . A likewise helical electrical-resistance heating element  35  is nested inside and in close contact with the flow coil. 
     Water enters the flow coil  33  through flow control valves located toward the left side of  FIG. 4 . The water flows through the coils of the flow coil, and out of the flow coil (rightward in the drawing) into the brew tray assembly  30 . The water flows inside the brew tray assembly, which holds a standard commercial coffee bag (not shown). The water flows into and through the coffee inside the bag. Brewed coffee exits the brew tray assembly through a brew tray outlet  38  near the bottom of the brew tray assembly. The brewed coffee then flows down through the lid  23  and into the container body  15  of the decanter  12 . 
     The flow coil  33  and the heating element  35  are both made of copper or other good thermal conductors. The coffee maker&#39;s control system directs electrical current through the heating element. Electrical resistance generates heat in the heating element, which is transferred through the flow coil into water flowing through the coil. Water is heated in the flow coil at standard cabin pressure; no heavy or bulky pressure vessel is present or required. 
       FIG. 5  is a schematic plumbing diagram illustrating fluid flow through the coffee maker assembly. Potable water is held inside an aircraft&#39;s on-board galley water supply reservoir  40 . The overall coffee maker assembly is connected to the galley water supply reservoir through a galley water supply connection  41 . The galley water supply connection allows the coffee maker assembly to be disconnected from the galley water supply if the coffee maker assembly is removed from the aircraft. 
     A rail water supply connection  42  connects the coffee maker assembly to the water supply line between the coffee maker rail  25  and the coffee maker control assembly  28  (see  FIG. 3 ). The rail water supply connection  42  includes a self-closing valve that closes when the coffee maker control assembly  28  is removed from the rail  25 . This valve keeps water from spilling from the galley water supply into the aircraft cabin when the control assembly is not in place on the rail. 
     Water flows from the galley water supply  40  through the connections  41  and  42  through a water filter  43 . The water filter keeps particles suspended in the galley water supply from entering a pair of valves downstream of the water filter. A water flow control solenoid valve  44  opens and closes to control the flow of water from the supply into the coffee maker. A flow rate control valve  45  maintains a steady water flow rate regardless of fluctuations in the galley water supply pressure. 
     Water flows from these two valves  44  and  45  into a flow-through heater  48 . The flow-through heater includes the flow coil  33  and the heating element  35  (see  FIG. 4 ). Water flowing through the flow coil is heated as power is supplied to the heating element. Water can be drained from the heater  48  back into the galley water supply reservoir  40  through a system drain check valve  49 . 
     A water level sensor  51  monitors the water level inside the heater  48 . The coffee maker control system uses information from the water level sensor to prevent the heater from operating when the water level is low in the heater. 
     A diverter valve  52  directs water from the heater  48  to either a water spigot  54  or a coffee brew nozzle  56 . The water spigot allows a user to withdraw hot or cold water from the coffee maker. The brew nozzle channels hot water into the coffee maker&#39;s brew tray assembly  30 . The brew tray assembly provides a chamber for coffee grounds through which heated water will pass to create coffee. Water that enters the chamber and flows through ground coffee held inside a standard flow-through coffee bag. Brewed coffee leaves the chamber through a brew tray drain valve  55 . 
     The brewed coffee leaving the brew tray assembly  30  through the brew tray drain valve  55  is directed into a decanter  12  through a decanter anti-spill valve  57 . Brewed coffee can be held inside this decanter until the decanter is removed from the assembly so that the coffee can be served to the aircraft&#39;s passengers and crew. 
       FIG. 6  is a simplified schematic diagram of the coffee maker&#39;s electrical system  60 . The coffee maker&#39;s operations are controlled by a central electrical controller  63 , which receives three-phase, 115 volt, 400 Hz alternating current from the aircraft&#39;s on-board electrical power supply through an aircraft interface  61 . The AC power is rectified and supplied as single-phase direct current to the coil heating element  35 . The heating element is protected by a heating element thermostat  65 . Power to the heating element is interrupted automatically if the heating element&#39;s temperature (as determined by the thermostat) exceeds a predetermined maximum allowable value. 
     The coffee maker&#39;s electrical controller  63  is connected to the aircraft interface  61  and the aircraft&#39;s CAN (controller area network) bus interface  62  via a rail interface  64 , which joins the coffee maker&#39;s electrical controller  63  to the aircraft&#39;s systems when the coffee maker control assembly  28  is installed onto the coffee maker rail  25  (see  FIG. 3 ). 
     The coffee maker&#39;s various systems, controls, and indicators are linked to the central electrical controller  63  through a multi-pin connector  67 . The heating element  35  and the overheat thermostat  65  are connected as shown in  FIG. 6  to pins  1 ,  2 , and  3  of the multi-pin connector. Indicators and switches on the coffee maker&#39;s front side control panel  13  are connected to the controller  63  through pins  4 - 13 , various other probes and sensors through pins  14 - 19 , and two storage memories through pins  20  and  21 . Pin  22  serves as a common ground or return for the elements connected to pins  4 - 21 . Flow control solenoid valve  44  and diverter valve  52  (see  FIG. 5 ) each connect to the central electrical controller  63  through their own individual connectors. 
     The electrical system  60  of  FIG. 6  includes several sensors that operate to prevent mishaps and to ensure proper operation of the coffee maker assembly. As noted above, a water level sensor  51  monitors the level of water inside the flow through heater  48  (see  FIG. 5 ). If insufficient water is present in the coil, the system controller will prevent power delivery to the heating coil  35  to avoid boiling the flow coil dry or otherwise overheating the unit. If this should occur, a low water warning light emitting diode (“LED”) is illuminated on the coffee maker&#39;s control panel  13 . (The low water warning LED is shown connected to pin number  7  of the multi-pin connecter  67  in  FIG. 6 ; the water level sensor to pin number  14 .) 
     The heating element overheat thermostat  65  also acts to protect the heater  35  from over heating. This thermostat will interrupt the supply of power to the heater even if the controller  63  fails or is otherwise unable to prevent overheating in the heater coil  35 . 
     A “decanter-in-place” sensor is shown connected to pin  15  of the multi-pin connector  67 . This sensor determines whether a decanter  12  is properly in place in the coffee maker. If the decanter is missing, the water control solenoid valve  44  is closed to prevent water draining through the flow coil  33  to spill into the aircraft galley. When this occurs, the controller  63  will light the “decanter-in-place” warning LED shown connected to pin  8 . 
     A “brew-tray-in-place” sensor (shown connected to pin number  16  of the multi-pin connector  67 ) determines whether the system&#39;s brew tray is properly in place in the coffee maker. If the brew tray is partially open or removed from the assembly, as it would be, e.g., for the coffee bag to be changed, the solenoid valve  44  is likewise held closed to prevent hot water spilling into the galley. Such a condition will light the “brew-tray-in place” warning LED, which is shown connected to pin  9 . 
     Three temperature sensors measure water temperatures in the vicinity of the flow coil  33 . A flow coil inlet water temperature sensor (shown connected to pin number  19  of the multi-pin connector  67  in  FIG. 6 ) measures the temperature of the as yet unheated water flowing into the upstream side of the flow coil. A second, mid-flow coil temperature sensor (shown connected to pin number  18 ) measures the temperature of the heater coil or sheath at a point near the mid-point of the water&#39;s flow path through the coil. Finally, a third, flow coil outlet water temperature sensor (shown connected to pin number  17 ) measures the temperature of the heated water leaving the downstream side of the flow coil. 
     Storage memory can record and store data for identification, diagnostic, or other purposes. In  FIG. 6 , a serial number memory (shown connected to pin number  20 ) is present to record identifying information and maintenance records for a particular coffee maker assembly. An event counter memory (connected to pin number  21 ) logs the occurrence of predetermined events (e.g., system activation, brew tray or decanter removals, heating coil heating cycles, system fault conditions, etc.) that may be useful in determining whether the system is performing properly or in performing maintenance on the system. 
     To make coffee, a user places a fresh coffee bag in the brew tray, slides the brew tray into position, and makes sure a decanter is properly in place in the coffee maker. Activating an on/off switch (which is shown in  FIG. 6  connected to pin number  10  of the electrical controller&#39;s multi-pin connector  67 ) supplies power to the control system. A power on LED (shown connected to pin  5 ) illuminates to signal the user that the unit is receiving power from the aircraft. 
     Activating a brew switch (connected to pin  11  of the multi-pin controller  67 ) starts a brew cycle. A brewing indicator LED (connected to pin  6 ) illuminates on the control panel  13  to confirm the brew cycle&#39;s initiation. Assuming the water level probe, decanter-in-place sensor, and brew-tray-in-place sensor all return their expected confirmations, the flow control solenoid valve  44  (see  FIG. 5 ) opens to allow water to flow into the coil  33  (see  FIG. 4 ) as power flows through the heating element  35 . 
     Water heating is monitored by the three temperature sensors in the vicinity of the coil—the flow coil inlet water temperature sensor, the mid-flow heater coil temperature sensor, and the flow coil outlet water temperature sensor (see  FIG. 6 ). The controller  63  uses information from these sensors to control power delivery to the heating coil and the flow of water through the flow coil. 
     Hot water enters the brew tray assembly  30  through the brew nozzle  56  (see  FIG. 5 ). The hot water seeps through the ground coffee in the coffee bag inside the brew tray, and hot coffee leaves the bag and the brew tray through the brew tray drain valve  55 . Hot coffee enters the decanter  12  through the decanter&#39;s own decanter anti-spill valve  57 . 
     The three temperature sensors in the vicinity of the flow coil  33  allow for precise control of brewing and the collection of diagnostic information regarding the system&#39;s performance. In normal operation, power delivery to the heating element  35  is controlled to ensure the delivery of water at the proper temperature at the downstream end of the flow coil. The electrical controller can process readings from any or all of the three temperature sensors to adjust the power level applied to the heating element. 
     In some cases, the flow coil inlet water temperature sensor just upstream of the flow coil may detect an unusually low temperature, indicating unusually cold water in the galley water supply reservoir. Under such conditions, the heater may not be able to produce sufficient to heat the water fully to the desired temperature with the solenoid flow control valve  44  continuously open. In such a case, the electrical controller can pulse the flow control valve between its open and closed positions to limit the water&#39;s flow rate through the flow coil  33  so that the heater power is sufficient to heat the water fully to its proper temperature. 
     As another example, an unusually high temperature difference between the mid-coil heater sheath temperature sensor (located on the exterior of the flow coil near the mid-point of the flow path) and the flow coil outlet water temperature sensor may indicate an accumulation of heat-insulating calcium scale or a similar problem in the flow coil. In this case, the controller might cause a service warning LED on the assembly&#39;s control panel to illuminate. In some circumstances the controller might also shut down the unit until it can be serviced. 
     A decanter liquid level sensor  73  (shown connected to pins  23  and  24  of multi-pin connector  67  in  FIG. 6 ) detects the presence of liquid at a level near the top of the decanter&#39;s lid. This signals the controller  63  to cease delivery of water to the flow coil. The flow control solenoid  44  closes, and the small amount of water remaining in the coil drains through the remainder of the system and into the decanter. The decanter liquid level sensor is low enough in the decanter so that the small amount of coffee that continues to flow into the decanter after the decanter liquid level sensor is first activated will not overflow the decanter. The decanter can then be removed from the system and the fresh-brewed coffee served out to the passengers and crew inside the aircraft. 
     An in-decanter coffee heating element  74  is connected to pins  25  and  26  of the multi-pin connector  67 . The heating element can take a variety of forms. As an example, a resistive heating element can be provided in the walls or bottom of the decanter, with leads and contacts to conduct electrical current through the heating element. Such a heating element can allow coffee to be kept hot inside the decanter for extended periods before it is served. 
       FIG. 7  is a perspective view of the decanter lid  23 . A pair of electrically conductive (metal-plated or otherwise) capacitance plates  75  are suspended from the main body of the lid on substantially vertical plate supports  78 . Each of the capacitance plates is in electrical contact via its plate support with an electrical contact surface  80 , one such surface on either side of the lid. 
     These electrical contact surfaces are in contact with electrically-conductive mating contact surfaces in the coffee maker control assembly  28  (see  FIG. 1 ). The mating contact surfaces are connected in turn to the system&#39;s electrical controller  63 . (The contact surfaces are connected to contact pins numbered  23  and  24  in the multi-pin connector  67  shown in  FIG. 6 .) When the coffee inside the decanter  12  reaches the level of the plates  75 , the electrical capacitance between the plates changes substantially, because at that point there is liquid (coffee) instead of air between the plates. This capacitance change is detected by the controller  63 . The controller then closes the flow control valve  44  as described above to prevent the decanter&#39;s being overfilled. 
       FIG. 8  is a section view showing the lid  23  in place on the decanter  12  and the position of the capacitance plates  75  inside the decanter&#39;s container body  15 . As the drawing illustrates, the capacitance plates hang down some distance into the container body, which allows some overfill volume over the plates for receiving the small amount of excess coffee that drains out of the system after the coffee is first detected at the plates. 
     The lid  23  is rotatable on the decanter through three positions. In the first position, which is shown in  FIG. 8 , the lid is fixed (i.e., not removable) on the decanter with the spout opening closed. In the second position, the lid is likewise fixed on the decanter but the spout is open so that coffee can be poured. Finally, the third position allows the lid to be removed entirely from the decanter. The configuration of the lid is such that the decanter can be placed onto or removed from the assembly only when the lid is in the first position—the one in which the pour spout is closed. This helps to prevent spills when the decanter is taken from or replaced back on the coffee maker. 
     The configuration of the electrical contact surfaces  80  on either side of the lid is also advantageous because the mating contacts in the coffee maker slide across the contact surfaces every time the decanter is removed from or replaced into the coffee maker. This sliding contact wipes the contact surfaces against one another, which helps to clear any surface contamination from the contacts and to ensure reliable electrical contact and sensing between them. Similar electrical contacts can be provided conveniently here as well for the in-decanter heater that keeps coffee warm inside the decanter. 
       FIGS. 7 and 8  also illustrate the small opening  83  in the top of the lid  23 . As noted above, hot coffee enters the decanter through this opening in the lid. The opening should be large enough to receive the flow of coffee leaving the brew tray without spilling coffee on the lid, but should otherwise be as small as reasonably practical. 
     In the embodiment shown in these figures, brewed coffee enters the decanter through an essentially closed lid. Making the opening small helps to trap and conserve heat inside the decanter, which keeps the coffee hot until it is served. In addition, the small opening will tend to keep coffee from spilling out of the decanter if the decanter is tipped over accidentally. The surface area of the opening in the lid should be less than one-third of the area of the upper surface (i.e., at the interface between the coffee and the air above it) of the coffee standing in the pot. The ratio of the surface area of the lid opening to the coffee&#39;s upper surface area should more preferably be less than 10%, and ideally less than 5%. 
     A brew tray assembly  30  is illustrated in  FIG. 9 . The assembly&#39;s brew tray  47  includes an interior space  31  sized to receive a standard, commercially available ground coffee bag. Water directed by the system into the brew tray is filtered through the bag material and the ground coffee as the hot water flows through the bag. This water leaves the brew tray as hot coffee through the brew tray outlet  38 . The flow of hot coffee from the brew tray outlet is controlled by the brew tray drain valve  55 , which is described in more detail below. 
       FIG. 10  is a perspective view of an alternative coffee maker assembly  5 . This embodiment is similar in most respects to the embodiment described above. This embodiment, though, includes a pedestal  93  and a base  95  that support the coffee maker&#39;s control assembly  28  and brew tray assembly  30 . 
       FIG. 11  is a cut-away view showing interior structures of the alternate embodiment of  FIG. 10 . As this figure illustrates, this embodiment is mounted on a coffee maker rail  25  that is located under the control assembly  28  and the decanter  12 . As in the previous embodiment, the rail is mounted more-or-less permanently to structure inside the aircraft galley, and the rest of the coffee maker assembly slides over the rail. 
       FIG. 12  is a side section view of the top of the decanter  12  in place in the coffee maker assembly  5 . When coffee is brewed, hot water is directed from the diverter valve  52  into a brew nozzle disconnect  103  (see  FIG. 5 ). The brew nozzle disconnect includes a brew nozzle connector  105  that includes a brew nozzle connector inlet  106  that receives hot water from the flow-through heater, as directed by the diverter valve. The female brew nozzle connector is coupled to a male brew water receiver  107 . Water flows from the receiver through a brew nozzle supply tube  110  to the brew nozzle  56 . 
     The brew nozzle  56  is formed in a movable brew nozzle plate  112 . In this configuration, the brew nozzle plate presses down against a coffee bag held inside the interior space  31  of the brew tray  47 . This insures that hot water from the brew nozzle is well-directed into the bag and through the coffee. 
     Brewed coffee leaves the bag and the brew tray  47  through the brew ray outlet  38  at the back of the brew tray. The brew tray outlet includes a brew tray drain valve  55 . When the decanter  12  and the brew tray  47  are both in position as shown in  FIG. 12 , the brew tray drain valve is held open by a pivot lever  115 , which turns about a pivot  117  fixed to the assembly. 
     The decanter&#39;s pour spout  20  presses against a first lever arm  120 , which in turn presses the lever&#39;s second arm  122  against a spring-loaded brew tray drain valve body  125 . This urges a seal  127  on the valve body away from a valve seat  130  around the brew tray outlet  38 . The brew tray drain valve is thus opened to allow brewed coffee to exit the brew tray  47 . 
     The coffee leaves the brew tray  47  and enters the decanter  12  through the fill hole opening  83  in the top of the decanter&#39;s lid  23 . The coffee flows down through the lid and into the decanter past a decanter anti-spill valve  133 . The anti-spill valve is normally open, with a floatable valve ball  135  in a down position away from the anti-spill valve&#39;s valve seat  138 . The anti-spill valve  133  guards against spillage when the decanter  12  is removed from the coffee maker assembly and the coffee is being served. If the decanter tips over, the valve ball  135  will seat against the valve seat  138 , preventing coffee from flowing out of the decanter through the fill hole  83  in the lid  23 . 
       FIG. 13  is a side section view generally similar to that of  FIG. 12 , except that the decanter has been removed from the assembly, as it would be, e.g., while coffee is being served to passengers and crew in the aircraft cabin. With the decanter out of the assembly, the decanter&#39;s spout no longer bears against the first arm  120  of the pivot lever  115 . The pivot lever is free to pivot back around the pivot  117 , and the second lever arm  122  applies no force against the valve body  125 . The valve body&#39;s spring can thus urge the valve seal  127  into sealing contact with the valve seat  130  around the brew tray&#39;s outlet  38 . This keeps any coffee remaining in the brew tray  47  from dripping out into the space vacated by the decanter and otherwise leaking into the galley. 
     A Hall effect sensor detects the position of a small magnet mounted on the pivot lever  115 . The Hall effect sensor and the magnet function jointly as the “decanter in place” sensor shown connected to pin number  15  of the multi-pin connector  67  in the electrical schematic of  FIG. 6 . When the decanter is removed from the assembly, the Hall effect sensor detects this via the position of the magnet mounted on the lever, and the controller  63  closes the solenoid valve  44  to halt the flow of water through the flow through heater  48  and into the system (see  FIGS. 5 and 6 ). The controller also illuminates the “decanter in place” warning LED shown connected to pin  8  of the multi-pin connector  67  to alert the user that the decanter is not mounted in its holder. 
       FIG. 14  is a side section view showing the assembly  5  with the decanter  12  in place but the brew tray  47  partially removed. In this configuration the valve body  125  has moved away from the second arm  122  of the lever  115  so that no force is applied to the valve body by the lever. This allows the spring-loaded valve body to seal the brew tray outlet  38 . 
     Moving the brew tray (toward the left in  FIG. 14 ) out of the assembly also moves the brew nozzle plate  112  outward and upward, so that the male brew water receiver  107  decouples from the female brew nozzle connector  105 . This protects against the release of steam or hot water directly into the space vacated by the brew tray  47  when the brew tray is removed from the assembly, e.g., to reload a new coffee bag for another brew cycle. 
     A magnet on the brew nozzle plate  112  or otherwise mounted to the brew injector system cooperates with a second Hall effect sensor to serve as the “brew tray in place” sensor shown connected to pin  16  of the multi-pin connector  67  shown in  FIG. 6 . When the brew tray is ejected from the assembly, the brew tray in place sensor signals the controller  63  to close the solenoid valve  44  to halt the flow of water into the system. At the same time, the “brew tray in place warning” LED shown connected to pin  9  in  FIG. 6  illuminates to alert the user that the brew tray is partially ejected or wholly removed from the system. 
       FIG. 15  shows details of the coffee maker&#39;s control/indicator panel  13 . An on/off pushbutton  140  controls the supply of power to the coffee maker. This on/off pushbutton is the “power on” switch shown connected to pin  10  of the multi-pin connector  67  in  FIG. 6 . The pushbutton switch is backlit by a “power on” LED  143  when the unit is turned on with power supplied to the unit. This LED is shown connected to pin  4  of  FIG. 6 . 
     Pressing a brew switch pushbutton  145  initiates a brewing cycle to start water flowing through the system. The brew switch pushbutton is shown connected to pin  11  in  FIG. 6 . A “brewing” LED  147  back lights the brew switch pushbutton when water is flowing through the system and coffee is being brewed. The controller  63  signals the brewing indicator LED to flash when the brew cycle is complete and the coffee is ready or when a brew cycle has been interrupted by ejection of the brew tray  47  or removal of the decanter  12 . The brewing LED is shown connected to pin  5  of the multi-pin connector  67 . 
     A low water warning LED  153  (which is shown connected to pin  6  in  FIG. 6 ) lights to warn the user that the system is inoperative due to a low water condition at the flow through coil  33 , which is detected by the water level probe connected to pin  14 . 
     A service warning LED  155  illuminates to indicate that the unit requires service. The controller  63  might light this LED, for example, after a predetermined number of brew cycles is initiated and stored in the event counter memory, or when other conditions are detected that indicate that the system is in need of inspection or maintenance. This LED indicates a non-critical condition; the system can be operated while this LED is lit. The service warning LED is shown connected to pin  7  in  FIG. 6 , with the event counter memory shown connected to pin  21 . 
     A “decanter in place” warning LED  157  lights to indicate that the decanter  12  is not mounted properly in place underneath the coffee maker body. A similar “brew tray in place” warning LED  160  lights to show that the brew tray  47  has been partially ejected or removed completely from the assembly. The decanter in place warning LED is shown connected to pin  8  in  FIG. 6 , and the brew tray in place warning LED to pin  9 . 
     Pressing a hot water switch  163  on the control panel  13  causes hot water (heated by the flow-through heater) to be delivered by the diverter valve  52  (see  FIG. 5 ) to the water delivery spigot  54  located just to the right of the brew tray  47 . Pressing the cold water switch  165  likewise delivers water through the spigot, but in this case the heater is left unpowered as the water flows through the flow coil, so that cold water flows from the spigot. 
     Pressing a brew tray release button  167  to the left of the brew tray releases a latching mechanism, and the brew tray  47  is partially ejected from the coffee maker by a spring force acting on the brew tray or its mounting mechanism. The brew tray can then be gripped by the user, who can remove it entirely from the assembly. 
     The decanter  12  is normally secured in place by a latching mechanism inside the system. The user can press a pot release button  170  located underneath the brew tray release  167  to release the latching mechanism so that the decanter can be removed from the coffee maker by the user. 
     Although presently preferred embodiments of the invention are described above, improvements, modifications and additions may be developed and implemented without departing from the basic principles of the invention. For example, though the invention is described primarily as a system for making coffee, the invention or elements of it might well be adapted to dispense other beverages or other heated liquids for other purposes. 
     Although the invention is presently contemplated for use onboard aircraft, the same general configurations could find use in other vehicles such as trains and ships and space and military uses as well as any other forms of transportation in which passengers expect coffee service to be available. Usage of this invention could extend to fixed installation usages such as in institutions, schools, prisons&#39; restaurants or cafeterias, and the like. 
     Exemplary embodiments of coffee maker assemblies and their component parts are described in this document. These are merely examples, though, and the scope of the invention is not limited to these preferred embodiments. The full scope of the invention should be determined instead primarily by reference to the claims that follow, along with the full scope of equivalents to which those claims are legally entitled.