Metering Pump Piston Stroke Limitation Design

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Solution Overview

Problem

Existing metering pumps face issues with high complexity, increased production costs, and sealing problems due to the use of multiple components and inward protruding annular shoulders, which limit stroke and cause misalignment issues, especially with high viscosity products and varying metering volumes.

Innovation Solution

A metering pump design where the piston's stroke is limited by its contact with the inlet portion, eliminating the need for an upper stop and different component lengths, allowing for a compact configuration and variable metering volume by changing the housing length, with the compression spring positioned along the feed path to prevent metal contact with cosmetic products and facilitate realignment of the inlet valve.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If multiple components (inner piston plunger and outer piston element) are used to separate stop and sealing functions, then functional reliability is improved, but device complexity and production cost increase

Engineering Contradiction:

Improvefunctional reliabilityVSAvoiddevice complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The piston is divided into two concentric components: an inner piston plunger (made from stronger material) that performs the stop function, and an outer piston element (made from softer material) that performs the sealing function. This segmentation allows each component to be optimized for its specific function, improving overall reliability while managing complexity through functional separation.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The piston assembly uses composite material construction with the inner plunger made from a stronger material (e.g., metal or hard plastic) and the outer element made from a softer material (e.g., plastic or elastomer). This combination of materials enables simultaneous achievement of mechanical strength for stopping and compliance for sealing, resolving the contradiction between reliability and complexity.

Inventive Principle:

Principle #40Composite materials

2Manufacturing precision

If inward protruding annular shoulders are used to limit piston stroke, then stroke control is improved, but housing complexity and assembly difficulty increase

Engineering Contradiction:

Improvestroke controlVSAvoidhousing complexity

Core Design Contradiction:

Manufacturing precisionVSDevice complexity

Solution Approach 1:

Instead of creating complex inward protruding annular shoulders in the housing to limit stroke, the invention inverts the approach by having the piston components themselves provide the stroke limitation through their interaction with simpler housing features. The inner plunger contacts the inlet portion or a simple stop, while the outer element seals against the housing wall, eliminating the need for complex molded housing features.

Inventive Principle:

Principle #13The other way round (Inversion)

Solution Approach 2:

The complex stroke-limiting features are extracted from the housing and transferred to the piston assembly. The housing is simplified to provide only basic support and sealing surfaces, while the piston components carry the functional complexity of stroke control and sealing, reducing housing complexity and facilitating mold extraction.

Inventive Principle:

Principle #2Taking out (Extraction)

3Volume of moving object

If the piston contacts the inlet portion with reduced contact surface, then compact design is achieved, but pressure on the piston increases causing damage risk

Engineering Contradiction:

Improvepump volumeVSAvoidpiston durability

Core Design Contradiction:

Volume of moving objectVSStrength

Solution Approach 1:

The piston assembly uses local quality differentiation where the inner plunger has a harder, more durable contact surface specifically at the stroke-limiting contact point with the inlet portion or stop. The outer sealing surface maintains softer material properties for effective sealing. This localized material property optimization allows compact design while protecting against damage at high-stress contact points.

Inventive Principle:

Principle #3Local quality

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 design enhances functional safety, reduces assembly complexity, and allows for easy variation of metering volumes while maintaining all essential functions, ensuring reliable operation and cost-effectiveness by using the same piston and spring components across different metering volumes.

Implementation Method 1

The actuation element (push button or also lever) is typically preloaded by a compression coil spring into a starting position in an elastic manner

Methodology Applied

Scientific EffectElasticity: Elasticity

Implementation Method 2

actuating the metering pump in particular by depressing a piston suctions a predetermined volume of the product and feeds it to a product outlet

Methodology Applied

Scientific EffectMechanical Force: Mechanical Force

Data Source

PatentUS11786923B2Metering pump

Publication Date: 2023.10.17 CRYSTAL INT

AI summary

Disclosed is a metering pump comprising a housing that extends from an inlet region to an outlet and surrounds a piston which is urged into a starting position by a compression spring. In the metering pump the stop limiting the lifting stroke of the piston is formed by the lower end of the piston coming in contact with the inlet portion.