A flash boiler
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Solution Overview
Problem
Existing flash boilers for pour over water displacement drip coffee brewing machines require increasing energy towards the end of brewing, leading to water temperatures above 96 °C, which deteriorate the quality of brewed coffee by extracting excessive oils and imparting a bitter taste.
Innovation Solution
A flash boiler design with both upper and lower cold water inlets, where the hot water outlet and upper cold water inlet are located at the upper end of the housing, allowing for mixing of cold water with hot water to maintain the spray head temperature at 96 °C +/- 1.0 °C, preventing hot water return and accommodating different brewing machines.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the water holding tank is located below the spray head to enable water delivery, then water can be delivered to the spray head, but more energy is required towards the end of brewing, causing water temperature to exceed 96 °C and deteriorate coffee quality
Solution Approach 1:
The cold water inlet is divided into two separate inlets: an upper cold water inlet and a lower cold water inlet. This segmentation allows selective connection based on the water level in the holding tank, enabling the system to adapt to different brewing stages and maintain optimal temperature by preventing excessive heat generation when water level is low.
Solution Approach 2:
The system changes the operational parameter (which cold water inlet to use) based on the water level in the holding tank. When the water level is sufficient, the upper cold water inlet is used; when the water level drops, the lower cold water inlet is used instead. This parameter change prevents the need to deliver water against excessive height difference, thereby maintaining water temperature at or below 96 °C.
2Temperature
If the hot water outlet and upper cold water inlet are both located at the upper end of the housing, then cold water can mix with hot water to maintain temperature at 96 °C, but hot water may return through the cold water inlet
Solution Approach 1:
A non-return valve is introduced as an intermediary component between the upper cold water inlet and the water holding tank. This valve allows cold water to flow into the flash boiler while preventing hot water from returning through the same inlet, thereby maintaining temperature control reliability without compromising the mixing function.
3Ease of manufacture
If a single flash boiler design is used for different brewing machines, then manufacturing costs are reduced, but the varying head of water in different machines may be insufficient to deliver hot water to the spray head
Solution Approach 1:
The flash boiler is designed with both an upper cold water inlet and a lower cold water inlet, making it universally compatible with different brewing machine configurations. The dual inlet design allows the same flash boiler to function correctly whether the water holding tank is positioned high or low, as the appropriate inlet can be selected based on the specific machine's water head conditions.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Maintains optimal water temperature at the spray head for efficient coffee extraction while minimizing bitter compounds, reducing manufacturing costs by accommodating multiple brewing machines with a single design.
Implementation Method 1
As the water heats it expands, as steam is generated. This forces the water out of the flash boiler
Implementation Method 2
As the water heats it expands, as steam is generated
Implementation Method 3
some cold inlet water mixes with the hot water exiting the flash boiler
Implementation Method 4
all of the water in the holding tank is brought to near boiling point using a thermostatically-controlled heating element
Data Source
AI summary
A flash boiler (10) for a pour over water displacement drip coffee brewing machine, which flash boiler (10) is adapted to deliver hot water to a spray head of the brewing machine. The flash boiler (10) comprises a housing (11), a heating coil (not shown) within the housing (11), an upper cold water inlet (12) connectable to a water holding tank in the coffee brewing machine, and a hot water outlet (13), both the upper cold water inlet (12) and the hot water outlet (13) being located at the upper end (14) of the housing (11) as it is orientated, in use, such that a quantity of cold water entering the housing (11) through the upper cold water inlet (12) mixes with the hot water exiting the housing (11) through the hot water outlet (13), which quantity of water is sufficient to maintain the temperature of the water at the spray head at 96 °C +/- 1.0 °C. Water above 96 °C is generally accepted in the coffee brewing industry as being detrimental to the quality of the coffee output so there is an advantage to maintaining the temperature of the water at the spray head to close to the industry desired temperature of 96 °C.