Differential Bore Suck-Back Mechanism for Drip-Free Foam Pumps
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Foam dispensers often experience residual liquid reverting back to liquid and dripping after use, which is undesirable for maintaining hygiene and efficiency in dispensing foam products like soaps, sanitizers, and lotions.
Innovation Solution
A differential bore suck-back device with a housing having an upstream small bore and a downstream large bore, a dual body piston mechanism, and a biasing member that uses a flow restrictor to compress and expand a suck-back chamber, effectively drawing residual foam back into the chamber after use.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a foam pump is used to dispense foam by pumping liquid and air mixture through a foam cartridge, then foam generation is achieved, but residual liquid reverts back to liquid and drips from the foam cartridge after dispensing
Solution Approach 1:
The pump is divided into distinct functional segments: a pumping chamber for foam generation and a separate suck-back chamber for residual liquid recovery. The pumping chamber includes a pump piston and pump outlet, while the suck-back chamber includes a suck-back piston and is connected to the pump outlet through a fluid communication path. This segmentation allows each chamber to perform its specific function independently, preventing dripping while maintaining manageable structural complexity.
Solution Approach 2:
The suck-back chamber performs a preliminary recovery action by capturing residual liquid immediately after foam dispensing stops. The suck-back piston is biased by a spring to automatically draw residual liquid from the pump outlet through the fluid communication path back into the suck-back chamber, preventing the liquid from dripping out before it can be recovered.
2Device complexity
If residual foam is allowed to remain in the pump outlet after dispensing, then the pump structure remains simple, but the residual liquid reverts to liquid form and causes dripping
Solution Approach 1:
The suck-back chamber acts as an intermediary component between the pump outlet and the environment. It provides a controlled recovery path for residual liquid, preventing direct contact with the external environment that would cause dripping. The spring-biased suck-back piston mediates the recovery process by automatically drawing residual liquid back into the chamber through the fluid communication path.
Solution Approach 2:
The residual liquid that would normally be harmful (causing dripping and potential contamination) is converted into a recoverable resource. The suck-back chamber captures this residual liquid and draws it back through the fluid communication path, transforming the harmful dripping effect into a beneficial recovery process that eliminates waste and maintains hygiene.
3Reliability
If a suck-back chamber is added to recover residual liquid, then dripping is prevented, but the device complexity increases
Solution Approach 1:
The suck-back chamber is merged with the existing pump structure through fluid communication, creating an integrated system rather than a separate add-on component. The fluid communication path connects the pump outlet to the suck-back chamber, allowing the recovery function to be embedded within the overall pump architecture. This merging approach minimizes the increase in device complexity while achieving effective drip prevention.
Solution Approach 2:
The suck-back chamber is designed to be self-operating through the spring-biased suck-back piston that automatically draws residual liquid back into the chamber without requiring external control or additional energy input. The spring provides the necessary biasing force to move the suck-back piston, creating a self-service recovery mechanism that reduces the need for complex control systems.
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 significantly reduces dripping and enhances foam quality by ensuring that residual liquid is efficiently retracted into the system, maintaining a cleaner and more controlled dispensing process.
Implementation Method 1
the biasing member causes the suck-back chamber to expand and suck back residual foam into the suck-back chamber
Data Source
Figure 1
Figure 2
Figure 2A~2B
AI summary
An exemplary system for dispensing foam includes a container holding a foamable liquid, a pump, and a suck-back device. The suck back device has a housing having a small bore with first diameter and a large bore with a second diameter; a dual body piston with a first piston that reciprocates in the small bore and a second piston that reciprocates in the large bore; a flow restrictor located proximate the dual body piston, a suck back chamber formed at least in part by the large bore and the second piston, and a foam outlet. The flow restrictor is configured so that fluid flow into the suck back device causes the suck back chamber to compress and when the fluid flow stops, a biasing member causes the suck back chamber to expand and suck back residual foam into the suck back chamber.