Autoclavable Piston Guide Ring Seal Design

Solution Overview

Problem

Prior art pump mechanisms degrade during autoclaving due to deformation of plastic seals, leading to inadequate fluid pumping after sterilization.

Innovation Solution

A piston pump design featuring a metal cylindrical chamber with a piston and a guide ring, including a plastic annular sealing member with an annular locating flange that resists non-coaxial positioning during autoclaving, maintaining a coaxial seal under elevated temperatures.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a plastic sealing member is used in the pump mechanism, then the seal provides good fluid impermeability during normal operation, but the seal deforms during autoclaving at elevated temperatures, leading to inadequate pumping performance

Engineering Contradiction:

Improvesealing performanceVSAvoidseal shape stability

Core Design Contradiction:

ReliabilityVSStability of the object's composition

Solution Approach 1:

The patent changes the material parameter of the sealing member from plastic to metal, which fundamentally alters the thermal behavior. The metal sealing member maintains its structural integrity and shape stability at autoclaving temperatures (120-150°C) unlike plastic materials that deform, thereby resolving the contradiction between sealing performance and shape stability under thermal stress

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent employs a composite structure where a metal sealing member is integrated with a piston assembly that includes both metal (piston rod, chamber) and plastic (packing materials) components. The metal sealing member serves as the primary seal that withstands autoclaving, while other plastic components are positioned to minimize thermal exposure, creating a composite system that maintains overall functionality after sterilization

Inventive Principle:

Principle #40Composite materials

2Object-affected harmful factors

If the pump mechanism is subjected to autoclaving for sterilization, then the pump achieves complete sterilization, but the plastic seals become deformed and the pump performance degrades

Engineering Contradiction:

Improvesterilization effectivenessVSAvoidpumping performance

Core Design Contradiction:

Object-affected harmful factorsVSReliability

Solution Approach 1:

The patent changes the material parameter of the sealing member from plastic to metal, which fundamentally alters the thermal behavior. The metal sealing member maintains its structural integrity and shape stability at autoclaving temperatures (120-150°C) unlike plastic materials that deform, thereby resolving the contradiction between sealing performance and shape stability under thermal stress

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent employs a composite structure where a metal sealing member is integrated with a piston assembly that includes both metal (piston rod, chamber) and plastic (packing materials) components. The metal sealing member serves as the primary seal that withstands autoclaving, while other plastic components are positioned to minimize thermal exposure, creating a composite system that maintains overall functionality after sterilization

Inventive Principle:

Principle #40Composite materials

3Stability of the object's composition

If a metal sealing member is used instead of plastic, then the seal resists deformation during autoclaving, but the manufacturing complexity increases

Engineering Contradiction:

Improveseal shape stabilityVSAvoidmanufacturing simplicity

Core Design Contradiction:

Stability of the object's compositionVSEase of manufacture

Solution Approach 1:

The patent segments the piston assembly into distinct functional components: a metal sealing member for thermal resistance, a piston rod for mechanical movement, and separate packing materials for additional sealing. This segmentation allows each component to be optimized for its specific function and manufactured using appropriate processes, reducing overall manufacturing complexity despite the metal seal

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The metal sealing member serves multiple functions: it provides the primary fluid seal, maintains structural integrity during autoclaving, and guides the piston movement. By consolidating these functions into a single metal component rather than requiring multiple plastic parts, the patent actually simplifies the assembly process while maintaining shape stability

Inventive Principle:

Principle #6Universality (Multi-functionality)

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 design ensures a fluid-tight seal before and after autoclaving, preventing deformation of the sealing flange and maintaining pumping efficiency post-sterilization.

Implementation Method 1

piston-chamber forming member formed from metal having a cylindrical chamber... to assist in coaxially locating the piston portion coaxially of the central axis under temperatures exceeding 120 degrees Celsius

Methodology Applied

Scientific EffectThermal expansion: Thermal Expansion

Implementation Method 2

plastic annular sealing member with an annular locating flange that resists non-coaxial positioning during autoclaving, maintaining a coaxial seal under elevated temperatures

Methodology Applied

Scientific EffectThermal deformation: Deformation

Data Source

PatentEP1923141B1Autoclavable piston guide ring

Publication Date: 2011.04.06 GOTOHTI COM INC

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AI summary

A piston pump having a piston slidable within a cylindrical chamber, the piston carrying both a sealing flange to provide a slidable fluid impermeable seal with an inner wall of the chamber and a guide ring slidable in the chamber to assist in maintaining the sealing member coaxially within the chamber during autoclaving.