Hot beverage brewing apparatus

1. A hot beverage brewing apparatus for brewing a hot beverage by infusing an infusible material with pressurized hot water at an acceptable brewing temperature, said apparatus including:

A) a housing,

B) a brewing chamber supported by said housing for infusing the infusible material to brew the hot beverage, said brewing chamber including an inlet that receives the pressurized hot water at the acceptable brewing temperature and a hot beverage outlet for dispensing the hot beverage,

C) a tank structure for providing the pressurized hot water at the acceptable brewing temperature, said tank structure including:

i) an inner tank defining a cylindrical tank volume,

ii) an outer tank having:

a) a cylindrical body portion concentric with and spaced from said inner tank that forms an annular tank volume between said inner tank and said cylindrical body portion,

b) an upper portion that forms a common chamber over said cylindrical and annular tank volumes,

c) a sealable inlet through said outer tank to said common chamber through which inlet water at an inlet temperature is introduced, and

d) a hot water outlet for the pressurized hot water at the acceptable brewing temperature,

iii) a port network at the bottom of said inner and outer tanks that defines a plurality of open flow paths at the bottom of said inner and outer tanks, a first flow path being established between said cylindrical and annular tank volumes thereby to maintain the inlet water in the cylindrical and annular tank volumes at the same levels and a second flow path being established between said cylindrical and annular tank volumes and said hot water outlet, and

iv) a heater in the bottom of said inner tank for boiling the inlet water therein, the inlet water in said annular tank volume remaining substantially at the inlet temperature,

D) a water delivery tube connected between said hot water outlet and said brewing chamber, and

E) a sealing structure connected to said housing that moves between open and closed positions with respect to said sealable inlet thereby to unseal and seal said common chamber and said cylindrical and annular tank volumes, respectively whereby:

i) when said sealing structure is in its open position, the inlet water can be added to said cylindrical and annular tank volumes through said sealable inlet,

ii) when said sealing structure is closed and said heater is energized, steam under pressure is generated in said inner tank and in said common chamber to pressurize and discharge the water from both said cylindrical and annular tank volumes simultaneously through said port network, said hot water outlet and said water delivery tube

iii) whereupon the water from said cylindrical and annular tank volumes mixes and is delivered to said brewing chamber as the pressurized hot water at the acceptable brewing temperature.

2. The hot beverage brewing apparatus as recited in claim 1 wherein said heater is electrically powered and includes:

i) a sensor that indicates the temperature of water in said cylindrical tank volume, and

ii) a control responsive to said sensor that adjusts the power to said heater thereby to control the rate at which said heater produces steam and the delivery rate of the pressurized hot water to the infusible material.

3. The hot beverage brewing apparatus as recited in claim 1 wherein the quantities of the inlet water in said cylindrical and annular tank volumes are dependent upon the acceptable brewing temperature of the pressurized hot water being delivered to said brewing chamber, T 3 , and the temperatures of the boiling water in said cylindrical tank volume, T 1 , and the water in the annular tank volume T 2 , and the percentage, P, of the inlet water admitted through said sealable inlet that is in said cylindrical tank volume and the relationship among the temperatures is PT 1 +(100−P)T 2 =100 T 3 .

4. The hot beverage brewing apparatus as recited in claim 1 additionally including a lid attached to said housing for moving between open and closed positions, said sealing structure being attached to said lid for sealing said sealable inlet when said lid is in the closed position and exposing said inlet to receive the inlet water and direct the inlet water to said cylindrical and annular tank volumes when said lid is open.

5. The hot beverage brewing apparatus as recited in claim 4 wherein said tank structure additionally includes a vent above the maximum level of the water in said cylindrical and annular tank volumes that vents said cylindrical and annular tank volumes and an operator that blocks said vent after the inlet water in said cylindrical tank volume begins to boil.

6. The hot beverage brewing apparatus as recited in claim 1 wherein said tank structure includes a vent that selectively controls the pressure in said tank structure during brewing.

7. The hot beverage brewing apparatus as recited in claim 6 wherein said vent includes:

a) a vent passage from said common chamber to the exterior thereof, and

b) an operator that blocks said vent passage after the water in said cylindrical tank volume begins to boil.