Piston-Type Coffee Machine for Flexible Pressure Profiles
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Solution Overview
Problem
Piston-type coffee machines have limitations in pressure profile flexibility, require the piston to be in the upper position for water introduction, and suffer from sealing ring wear due to the discontinuity in the cylinder surface, restricting the ability to dispense varying beverage amounts and risking leakage.
Innovation Solution
A coffee machine design with a piston that can move translationally, featuring a pressure regulator to adjust boiler water pressure, a duct that opens only when the piston is in the second position, and a 'hold-to-operate' mechanism for the operating lever, allowing for variable pressure profiles and reduced wear on sealing rings.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If water introduction is limited to when the piston is in the upper position, then the machine structure is simple, but the pressure profile flexibility is greatly limited
Solution Approach 1:
The water introduction function is segmented from the piston position constraint. The filling hole is positioned in the cylinder wall independent of piston position, and a check valve controls water entry timing, allowing water introduction to occur regardless of where the piston is in its stroke cycle.
Solution Approach 2:
A check valve acts as an intermediary device between the water supply and the cylinder chamber. It mediates the water flow to ensure proper timing and direction, enabling flexible pressure profiles without requiring the piston to be in specific positions for water introduction.
2Reliability
If the piston must be in the upper position for water introduction, then the sealing system is simple, but sealing ring wear increases due to discontinuity in the cylinder surface
Solution Approach 1:
The water filling hole is extracted from the piston-cylinder sealing interface and relocated to a separate location on the cylinder wall. This removes the discontinuity from the sealing surface, allowing sealing rings to maintain continuous contact with the cylinder bore throughout the entire piston stroke, thereby reducing wear and improving reliability.
3Adaptability or versatility
If the operating lever and raising arm are rigidly connected, then the mechanism is simple, but the ability to adjust pressure profiles and beverage amounts is restricted
Solution Approach 1:
The rigid connection between the operating lever and raising arm is replaced with a dynamic, adjustable linkage system. This allows the operator to vary the mechanical advantage and control parameters during operation, enabling different pressure profiles and beverage amounts to be achieved through adjustable lever positions and raising arm configurations.
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
Enables flexible pressure profiles and adjustable beverage amounts without piston position constraints, reducing sealing ring wear and enhancing user safety through controlled pressure regulation.
Implementation Method 1
A spring is housed inside the cylinder. The piston is raised against the thrusting force of the spring actuated by an operating lever connected to the piston rod by means of a raising arm... As soon as the operator releases the operating lever, the spring (which is no longer retained) pushes the piston downwards
Implementation Method 2
a pressure regulator to adjust the pressure of the water from said first pressure to a second pressure
Implementation Method 3
a boiler configured for heating water supplied from a water main supply
Data Source
AI summary
A machine (100) for espresso coffee of the piston type is described. The machine comprises a cylinder (1), a piston (2) which is configured to perform a translation movement in said cylinder, a rod (4) having an end cooperating with said piston (2), an operating lever (5), a spring (3), a member (6) configured to cooperate with said rod (4) and to move said piston (2) from a first position to a second position in which said spring (3) is at least partially compressed, and an opening (71) for introducing water into said cylinder (1) configured so as to introduce water above the piston (2).