Flow system delivery system and beverage machine using same
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Solution Overview
Problem
Beverage machines without a water level sensor struggle to reliably distinguish between air and water flows, leading to pump deterioration and user dissatisfaction due to prolonged operation in dry conditions, as the impeller can rotate due to air flow when the flow meter is empty, causing the system to interpret it as water flow.
Innovation Solution
A flow delivery system that includes a pump, a monitoring device, and a controller to differentiate between liquid and gas flows by altering the pump drive signal, allowing for accurate determination of air or water flow, thereby preventing prolonged dry operation and eliminating the need for a water level sensor.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the flow meter is fully dry and air flow is generated by the pump, then the impeller rotates easily due to low friction, but the system incorrectly interprets air flow as water flow, leading to pump deterioration
Solution Approach 1:
The system changes the pump drive signal parameter from a first drive signal to a second drive signal to alter flow characteristics. This parameter change enables the system to detect whether the flow is liquid or gas by observing the response at different drive levels, resolving the inability to distinguish between air and water flow that causes incorrect operation
Solution Approach 2:
The controller monitors the flow characteristics and uses feedback from the flow meter response to determine whether liquid or gas is flowing. This feedback mechanism allows the system to adjust pump operation based on actual flow conditions, preventing pump deterioration from prolonged dry operation while maintaining accurate flow detection
2Device complexity
If the system uses the flow meter to detect when water has run out, then the water level sensor is eliminated, but the system cannot reliably distinguish between air and water flow, causing pump damage
Solution Approach 1:
The system maintains the simplified architecture without a water level sensor but introduces parameter changes in the pump drive signal to enable reliable flow type detection. By operating the pump at different drive signal levels and analyzing the flow meter response, the system can distinguish between air and water flow, ensuring reliable operation while keeping the device complexity low
3Ease of operation
If the pump operates in dry conditions for extended periods, then the pump lacks lubrication and cooling, but the system provides no feedback to the user about the problem
Solution Approach 1:
The controller continuously monitors flow characteristics and provides feedback about pump operating conditions. When air flow is detected indicating dry conditions, the system can alert the user through appropriate feedback mechanisms, enabling timely intervention to prevent pump damage from prolonged operation without lubrication and cooling
Solution Approach 2:
The system detects air flow conditions before significant pump damage occurs by monitoring flow characteristics at different drive signal levels. This preliminary detection allows the system to take preventive action by alerting the user or adjusting operation, extending pump service life by preventing extended dry operation
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
The system effectively determines when the water container is empty, preventing pump deterioration and providing user feedback, ensuring reliable operation and maintaining the pump's longevity without requiring a water level sensor.
Implementation Method 1
Flow meters used in the above types of appliance normally make use of the moving fluid stream to turn an impeller
Implementation Method 2
A magnetic sensor arrangement is for example provided, comprising a magnet or set of magnets on the impeller and a magnetic sensor
Implementation Method 3
self-priming versions allow more cost effective water supply systems. When a beverage appliance does not have a water level sensor it is expected that air will enter the water supply system each time the amount of water amount left in the water container is smaller than the selected beverage. After the water container has been refilled, the pump has to self-prime, during which an air flow is generated
Data Source
AI summary
A flow delivery system to deliver and monitor a liquid flow, using a pump, and a monitoring device (e.g. a flow meter) are described. A controller determines if the flow is a liquid flow or a gas flow by reducing a drive signal for the pump from a first drive signal to a second drive signal. This changes the characteristics of both the pump drive signal and the characteristics of the resulting flow. Based on the change in the characteristics, the flow is determined to be a liquid flow or a gas flow.