Manual Pump Return Passage for Partial Dose Control
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Solution Overview
Problem
Conventional manual pumps for fluid dispensers cannot deliver doses smaller than the pump chamber volume without reducing the piston stroke or chamber volume, leading to user dissatisfaction and high costs for manufacturing miniature pumps.
Innovation Solution
Incorporating a return passage that allows a fraction of the pressurized fluid to escape from the pump chamber without passing through the outlet valve, either through a leaky inlet valve or a bypass directly to the reservoir, allowing for partial dose redirection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the pump chamber volume is reduced to deliver smaller doses, then the dispensed fluid volume decreases, but the pump chamber volume and piston stroke are reduced, requiring complete redesign of the pump components
Solution Approach 1:
The pump system is segmented into two separate functions: the pump chamber maintains its original volume for efficient piston operation, while a new return passage segments the fluid flow path to divert excess fluid back to the reservoir, allowing the pump chamber to deliver only the required dose volume without redesign
Solution Approach 2:
A return passage is introduced as an intermediary element between the pump chamber and the reservoir. This intermediary component enables partial fluid redirection without modifying the pump chamber or piston stroke, serving as a mediator that resolves the contradiction between maintaining pump volume and reducing dispensed volume
2Quantity of substance
If a new miniature pump is manufactured to deliver smaller doses, then the dispensed fluid volume decreases, but the manufacturing cost increases significantly
Solution Approach 1:
The return passage is designed to be integrated into existing standard pump components (inlet valve movable member, valve seat, or pump body), allowing a single component to serve multiple functions: maintaining valve operation while simultaneously enabling fluid redirection. This eliminates the need for separate miniature pump manufacturing
Solution Approach 2:
Instead of changing the fundamental pump design parameters (chamber volume, piston stroke), the invention changes the flow distribution parameter by introducing the return passage. This parameter change allows dose volume reduction while maintaining all original pump dimensions and manufacturing specifications
3Quantity of substance
If the piston stroke is reduced to deliver smaller doses, then the dispensed fluid volume decreases, but the actuator rod stroke and pusher movement are reduced, causing user dissatisfaction
Solution Approach 1:
The excess fluid volume is extracted from the discharge path by diverting it through the return passage back to the reservoir. This extraction of unnecessary fluid volume allows the pump to maintain its full piston stroke for user satisfaction while delivering only the required dose volume through the outlet valve
Data Source
AI summary
A manual pump (P) having a pump body (B) defining a slide cylinder (F) for a piston (K) secured to an actuator rod (S); a pump chamber (C) and an outlet valve (V) arranged between the pump chamber (C) and a dispenser orifice (O) so as to dispense the fluid from the pump chamber (C). The pump includes an inlet valve (2, 12) arranged between the pump chamber (C) and an inlet (I) of the pump (P) to take the fluid into the pump chamber (C) from the reservoir (R), the inlet valve having a movable member (2) that selectively bears against a valve seat (12), a return passage (23) enabling a fraction of the fluid that is put under pressure in the pump chamber (C) to escape therefrom without passing via the outlet valve (V). The return passage (23) creates a lack of sealing at the inlet valve.