Pinch Valve Dispenser with Rotatable Bar and Load Cell
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Solution Overview
Problem
Existing liquid dispensers for dairy products and other liquids face accuracy issues as they rely on initial liquid levels for dispensing, leading to inaccuracies as the liquid level drops, and require disassembly for container installation and cleaning, with pinch valves not facilitating easy installation or removal of bulk containers.
Innovation Solution
A liquid dispenser with a computer-controlled pinch valve that uses a load cell to measure the liquid level and adjust valve open time based on the actual liquid volume, allowing for accurate dispensing of user-specified volumes without relying on initial levels and facilitating easy installation and removal of containers through a rotatable pinch bar.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If prior art pinch valves are used in liquid dispensers, then the valve can control fluid flow, but the valve requires disassembly for tube installation and removal
Solution Approach 1:
The pinch valve is divided into separate components: the valve body and the pinch bar are distinct elements that can be independently manipulated. The tube passes through the valve body, and the pinch bar can be rotated to engage or disengage from the tube, allowing the tube to be installed or removed without disassembling the entire valve assembly.
Solution Approach 2:
The pinch bar is designed to be rotatable about an axis, transforming a static valve structure into a dynamic one. This rotation capability allows the pinch bar to move between an engaged position (where it pinches the tube) and a disengaged position (where the tube can be freely installed or removed), enabling easy tube changes without full disassembly.
2Measurement precision
If dispensers rely on initial liquid levels for dispensing, then the system is simple to operate, but dispensing accuracy deteriorates as liquid level drops
Solution Approach 1:
A load cell provides continuous feedback on the actual liquid level in the container. The controller receives this feedback signal and uses it to dynamically adjust the valve open time, ensuring accurate dispensing regardless of the current liquid level. This closed-loop feedback system maintains precision throughout the depletion of the liquid.
Solution Approach 2:
The traditional mechanical float-based level sensing is replaced with an electronic load cell that measures weight. This substitution provides more accurate and reliable liquid level information, enabling the controller to compensate for level changes and maintain consistent dispensing accuracy throughout the container's depletion.
3Measurement precision
If controllers calculate dispensing valve open times using user-specified starting amounts, then the system is easy to program, but dispensing accuracy depends on accuracy of initial level
Solution Approach 1:
The load cell automatically measures the actual liquid level without requiring user input. The system serves itself by continuously monitoring the liquid level and using this information to calculate the appropriate valve open time, eliminating the need for users to accurately measure and input the starting volume.
Solution Approach 2:
The load cell performs preliminary measurement of the actual liquid level before dispensing begins. This advance measurement allows the controller to pre-calculate the correct dispensing parameters based on the actual rather than estimated liquid volume, ensuring accuracy from the first dispense.
4Measurement precision
If dispensing valves require finite time to open and close, then the valve mechanism is simple, but dispensing accuracy deteriorates as liquid level approaches zero
Solution Approach 1:
The load cell provides real-time feedback on liquid level, allowing the controller to continuously update the valve open time calculation. As the liquid level approaches zero, the controller uses the current level information to precisely calculate the remaining dispensable volume and adjusts the valve open time accordingly, compensating for the valve's response time and maintaining accuracy even at very low levels.
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 ensures accurate dispensing of fixed volumes throughout the depletion of the liquid, maintaining precision and simplifying the handling of containers by allowing for easy installation and cleaning without disassembly.
Implementation Method 1
A liquid dispenser with a computer-controlled pinch valve that uses a load cell to measure the liquid level
Implementation Method 2
Electromechanical closure of a pinch valve is typically accomplished by activating a solenoid to draw a spring-biased bar or gate against an elastomeric sleeve or tube
Implementation Method 3
activating a solenoid to draw a spring-biased bar or gate against an elastomeric sleeve or tube
Data Source
AI summary
Fixed-volumes of liquid are measured and dispensed from a container by empirically determining the liquid surface height and opening a dispensing valve for a time period that is calculated using a volume of liquid specified to be dispensed and the empirically-determined liquid surface height. The liquid surface height in the container is determined empirically for initial and subsequent volumes of liquid that are dispensed. Dispensing accuracy is maintained whether the container is full or nearly empty.