Draw back push pump
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Solution Overview
Problem
Existing liquid dispensers, such as those for soap and honey, often experience issues with dripping and stringing due to residual fluid at the nozzle outlet, leading to obstruction and uneven dispensing, which can result in unwanted spraying or the appearance of leakage.
Innovation Solution
A piston pump dispenser with a reciprocating piston arrangement that, after dispensing fluid, draws back fluid through the outlet to reduce dripping and stringing, utilizing a one-way valve and flexible discs to manage fluid flow and create a vacuum for efficient fluid retrieval.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional piston pump dispenser is used to dispense fluid, then fluid can be dispensed from the outlet, but residual fluid remains at the outlet causing dripping and stringing
Solution Approach 1:
The patent applies preliminary anti-action by implementing a draw-back mechanism that actively removes residual fluid from the outlet before the dispenser is set down. The piston automatically retracts a portion of the dispensed fluid back into the pump chamber, preventing the fluid from hanging at the outlet where it would otherwise drip or string. This counter-action occurs during the normal dispensing cycle without requiring additional user input.
2Object-generated harmful factors
If the piston pump draws back fluid from the outlet, then dripping and stringing are reduced, but the device complexity increases
Solution Approach 1:
The patent merges the draw-back function with the existing reciprocating piston dispensing mechanism. The same piston that performs the forward dispensing stroke also performs the backward draw-back stroke by simply reversing its direction of motion. The outlet valve and chamber structure serve dual purposes: allowing fluid egress during dispensing and enabling fluid retraction during the return stroke. This integration avoids adding separate mechanical components for the draw-back function.
Solution Approach 2:
The outlet valve and pump chamber are designed to serve multiple functions: they control fluid egress during the dispensing stroke and simultaneously enable fluid retraction during the return stroke. The valve structure acts as both an outlet controller and a draw-back enabler, while the chamber serves as both a fluid storage space and a retraction pathway. This multi-functionality reduces the need for additional specialized components.
3Object-generated harmful factors
If residual fluid remains at the outlet, then the outlet appears to be leaking, but implementing a draw-back mechanism increases manufacturing complexity
Solution Approach 1:
The patent segments the pump chamber into distinct functional zones: a main fluid storage chamber and a draw-back reception area. The outlet valve is positioned to create a controlled transition zone between these areas. This segmentation allows the draw-back fluid to be contained in a specific region without requiring complex sealing arrangements throughout the entire chamber, simplifying manufacturing while achieving the desired fluid retraction.
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 solution effectively minimizes dripping and stringing, ensuring consistent and controlled dispensing by drawing back fluid through the nozzle, preventing obstruction and maintaining a clean appearance by eliminating the appearance of leakage.
Implementation Method 1
The valve comprises a resilient disc which opens when pressure behind a piston exceeds pressure in front of the piston by a predetermined amount
Implementation Method 2
on movement of the piston outwardly in a charging stroke creating a vacuum drawing fluid from the outlet into the chamber
Data Source
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AI summary
A piston pump dispenser having a reciprocating piston pump arrangement which in a dispensing stroke dispenses fluid from an outlet and in a charging stroke draws fluid from a reservoir and also draws back fluid from the outlet.