Reciprocating Piston Pump Draw-Back to Prevent Dripping
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing fluid dispensers, such as those for liquids like soap and honey, often experience issues with dripping and stringing due to residual fluid at the outlet, leading to obstruction and uneven dispensing, which can result in spraying or 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, featuring a piston chamber with a one-way valve and radially extending discs to control fluid flow, ensuring efficient fluid retrieval and prevention of future obstructions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If fluid is dispensed continuously from the outlet, then dispensing efficiency is improved, but residual fluid accumulates at the outlet causing dripping and stringing
Solution Approach 1:
The piston pump operates with periodic reciprocating strokes, creating alternating dispensing and draw-back phases. During the draw-back stroke, the piston reverses to suction residual fluid from the outlet back into the reservoir, preventing dripping and stringing while maintaining efficient periodic dispensing
2Ease of operation
If the outlet area is reduced to prevent dripping, then fluid control is improved, but fluid flow obstruction increases
Solution Approach 1:
The draw-back stroke continuously removes residual fluid from the outlet area immediately after dispensing, ensuring the outlet remains clear. This continuous action prevents both dripping and flow obstruction by maintaining outlet cleanliness without requiring orifice reduction
3Speed
If residual fluid is left at the outlet, then dispensing speed is improved, but future dispensing reliability deteriorates
Solution Approach 1:
The system discards residual fluid from the outlet by suctioning it back into the reservoir during the draw-back stroke. This recovery action prevents outlet obstruction and maintains dispensing reliability while allowing high-speed dispensing during the forward stroke
4Device complexity
If a simple piston pump design is used, then device complexity is reduced, but fluid draw-back capability is insufficient
Solution Approach 1:
The piston is segmented into a body portion and a stem portion with the outlet positioned in the stem. This segmentation allows the outlet to be strategically located within the fluid path, enabling effective draw-back of residual fluid through the outlet into the reservoir while maintaining a relatively simple overall pump structure
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 by ensuring fluid is drawn back into the reservoir, maintaining the dispensing area and preventing obstructions, thus ensuring consistent and controlled fluid dispensing without staining or leakage.
Implementation Method 1
a one-way valve between the reservoir and the chamber permitting fluid flow through the inner end of said chamber, only from the reservoir to the chamber
Implementation Method 2
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
Implementation Method 3
the inner disc elastically deforming away from the chamber wall of the outer chamber portion to permit fluid flow in the outer chamber portion past the inner disc in an outward direction
Implementation Method 4
the tubular member has its outlet opening downwardly and fluid passing through the tubular member is drawn downwardly by the forces of gravity
Data Source
Figure 1
Figure 2
Figure 3
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.