Beverage Pump Half-Cycle Control for Flow Rate Without Flow Meter
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Solution Overview
Problem
Existing beverage preparation devices face challenges in miniaturization and cost reduction while maintaining precise control over fluid flow rate and volume without dedicated flow meters, leading to unreliable and noisy pump activation.
Innovation Solution
A beverage preparation device with an electrically operated pump controlled by a processing unit that energizes the pump only during selected half cycles of a waveform, based on a target flow rate and maximum flow rate ratio, ensuring homogeneous activation and continuous fluid flow without the need for a flow meter.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a dedicated flow meter is installed in the fluid circuit to detect and control flow rate, then measurement precision and control reliability are improved, but device complexity and manufacturing cost increase
Solution Approach 1:
The invention extracts the flow measurement function from a dedicated flow meter and relocates it to the pump controller by measuring electrical parameters (current, voltage, power) of the pump motor. This eliminates the need for a separate flow meter while maintaining measurement capability through electrical measurements that correlate with fluid flow rate.
Solution Approach 2:
The pump controller is given multi-functionality by making it responsible for both pump control and flow rate measurement. The same processing unit that controls pump operation also calculates flow rate based on electrical parameters, thereby serving dual purposes with a single component.
2Adaptability or versatility
If the pump is activated in irregular manner to adjust flow rate, then flow rate control flexibility is improved, but noise and reliability worsen due to pump member interaction with stop member
Solution Approach 1:
The invention applies periodic action by activating the pump in regular intervals based on a calculated duty cycle. The pump is switched on and off periodically at frequencies above human hearing threshold, creating a homogenized flow effect while avoiding irregular activation patterns that cause noise and mechanical stress.
Solution Approach 2:
The invention uses dynamic control by adjusting the duty cycle percentage based on the ratio of target flow rate to maximum flow rate. The processing unit dynamically calculates and adjusts the pump activation pattern to match the desired flow rate while maintaining regular operation cycles.
3Adaptability or versatility
If the pump activation pattern is irregular to achieve target flow rate, then flow rate adaptability is improved, but beverage preparation reproducibility worsens
Solution Approach 1:
The invention implements feedback control by continuously monitoring the actual flow rate through electrical parameter measurements and comparing it with the target flow rate. The processing unit adjusts the pump duty cycle based on this feedback to maintain accurate and reproducible flow rates for beverage preparation.
Solution Approach 2:
The invention applies preliminary action by pre-calculating the optimal duty cycle based on the ratio of target to maximum flow rate before pump activation. This ensures that the pump operates in a predictable and reproducible manner from the start of each beverage preparation cycle.
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 solution allows for precise control of fluid flow rates as a fraction of the maximum flow rate, reducing noise and maintaining reproducible beverage strength and volume, while eliminating the need for a flow meter and burst fire control mechanisms.
Implementation Method 1
The pump is a solenoid pump comprising a pumping member axially displaceable between a spring-loaded position and a spring-released end position under control of a solenoid
Implementation Method 2
A spring is mounted behind the pumping member such that the spring is compressed when the pumping member is moved towards the inlet under control of the solenoid
Data Source
AI summary
The present invention relates to a beverage preparation device designed for preparing a beverage upon injection of liquid into an ingredients-containing cartridge, the device comprising a pump (106) coupled between a fluid inlet (102) and a fluid outlet (104) for pumping the fluid from said inlet to said outlet, and a processing unit (108) for the pump (106) adapted to control an operation of the pump in response to an electrical energy (121) having a wave form such that the pump is energized only throughout selected half cycles (a1,a2,a3 . . . an) of the wave form of the electrical energy, wherein the processing unit (108) is configured to determine the respective selected half cycles (a1,a2,a3 . . . an) in which the pump is energized based on a target ratio (TR) of a target flow rate (FR) and a predefined maximum flow rate of the pump, and based on the calculation of an activation ratio (AR) of the number of past half cycles (A) for which the pump was energized to the number of overall half cycles (B) during a respective beverage preparation process. The present invention further relates to a method for controlling a pump in a beverage preparation device.