Dual-Filter Drinks Machine Layout for Flow Meter Limescale Protection
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Solution Overview
Problem
Existing vending machines face contamination issues due to limescale deposits carried by the return line into the flow meter, leading to measurement inaccuracies and potential damage, as the return line opens into the inlet line downstream of the filter, exposing the meter to unfiltered water.
Innovation Solution
The implementation of two filters in a drinks machine, a pre-filter within the liquid tank and a fine filter between the outlet connector and the flow meter, with the return line connecting between them, ensuring that liquid is filtered multiple times before reaching the flow meter, preventing limescale deposits from reaching the meter.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single filter is used in the supply line, then the device complexity is reduced, but the flow meter becomes contaminated by limescale deposits from the return line
Solution Approach 1:
The filter system is segmented into two distinct filters: a pre-filter (6) located in the liquid tank and a fine filter (7) positioned between the outlet nozzle and flow meter. This segmentation allows the pre-filter to handle initial filtration of the water tank, while the fine filter provides additional filtration specifically protecting the flow meter from limescale deposits that may return through the return line (8). The segmented approach distributes the filtration load and provides targeted protection where most needed.
Solution Approach 2:
The fine filter (7) acts as an intermediary component between the outlet nozzle (3) and the flow meter (5), specifically designed to intercept limescale deposits before they can reach the flow meter. This intermediary filter is strategically positioned to handle the contaminated water returning through the return line, protecting the sensitive flow meter measurement system from harmful deposits.
2Stress or pressure
If the return line opens downstream of the filter, then the pressure relief function is achieved, but the flow meter is exposed to unfiltered water with limescale deposits
Solution Approach 1:
The fine filter (7) is positioned upstream of the flow meter (5) in the path of returning water, performing preliminary filtration action on water that may return through the return line (8) from the brewing unit or safety valve (9). This preliminary filtration ensures that even though the return line opens downstream of the main filter for pressure relief, the flow meter is still protected from limescale deposits through the intermediate fine filter.
3Reliability
If a larger filter surface area is needed, then filtration effectiveness improves, but the space required increases
Solution Approach 1:
The pre-filter (6) is nested within the liquid tank (2), utilizing the existing tank volume to house the filter without requiring additional external space. This nesting approach allows for a relatively large filter surface area to be accommodated within the confines of the water tank, providing effective filtration while maintaining compact overall dimensions of the beverage dispensing machine.
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
This arrangement effectively prevents limescale deposits from reaching the flow meter, ensuring accurate measurements and extending the meter's lifespan by maintaining its cleanliness and functionality.
Implementation Method 1
a first filter (6) is arranged upstream of the outlet nozzle (3)... the liquid drawn from the liquid tank (2) can be pre-filtered via the first filter (6)
Implementation Method 2
a second filter (7) is arranged between the outlet nozzle (3) and the flow meter (5)... cleaned again via the second filter (7) before the liquid flows through the flow meter (5)
Data Source
Figure 1
AI summary
The invention relates to a drinks machine (1) comprising a fluid tank (2) and an outlet connection (3) connected to a flow meter (5) by means of a pipeline (4), a first filter (6) being arranged upstream of the outlet connection (3), a second filter (7) being arranged between the outlet connection (3) and the flow meter (5), and a return conduit (8) opening into said outlet connection (3) downstream of the first filter (6) and upstream of the second filter (7). This allows the flow meter (5) to be protected from impurities in a reliable manner.