Needle-to-Housing Fitting for Low-Volume Sealed Sampling

Solution Overview

Problem

There is a need for improved sampling in chromatographic sample separation systems, particularly in high-performance liquid chromatography, to minimize fluidic flow path and eliminate unnecessary volume, while ensuring a sealed and efficient injection of sample fluids into the mobile phase.

Innovation Solution

A sampling unit comprising a needle, housing, and fitting with cone-to-cone coupling, which allows for a direct fluidic coupling between the needle and housing channels, eliminating the need for a seat capillary and minimizing the fluidic flow path, and ensuring a sealed connection.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a commonly used seat capillary is used to connect needle and housing, then the connection is sealed, but unnecessary volume is introduced and fluidic flow path is extended

Engineering Contradiction:

Improvesealed connectionVSAvoidfluidic volume

Core Design Contradiction:

ReliabilityVSVolume of moving object

Solution Approach 1:

The patent removes the seat capillary component from the traditional sampling system. Instead of using a separate capillary to connect the needle to the housing, the invention integrates the fluidic path directly through the needle tip insertion into the housing cavity, eliminating the intermediate capillary volume and reducing dead volume in the system.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The patent merges the functions of the needle, seat capillary, and housing connection into a single integrated fluidic path. The needle tip directly inserts into the housing cavity, combining what were previously separate components (needle + capillary + housing) into a more compact arrangement that reduces overall fluidic volume while maintaining sealing.

Inventive Principle:

Principle #5Merging (Combining)

2Reliability

If a commonly used seat capillary is used to connect needle and housing, then the connection is sealed, but the fluidic flow path is extended

Engineering Contradiction:

Improvesealed connectionVSAvoidfluidic flow path

Core Design Contradiction:

ReliabilityVSLength of moving object

Solution Approach 1:

The patent removes the seat capillary component from the traditional sampling system. Instead of using a separate capillary to connect the needle to the housing, the invention integrates the fluidic path directly through the needle tip insertion into the housing cavity, eliminating the intermediate capillary volume and reducing dead volume in the system.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The patent merges the functions of the needle, seat capillary, and housing connection into a single integrated fluidic path. The needle tip directly inserts into the housing cavity, combining what were previously separate components (needle + capillary + housing) into a more compact arrangement that reduces overall fluidic volume while maintaining sealing.

Inventive Principle:

Principle #5Merging (Combining)

3Length of moving object

If the needle is directly inserted into the housing cavity, then the fluidic flow path is minimized, but sealing between needle and housing may be compromised

Engineering Contradiction:

Improvefluidic flow pathVSAvoidsealed connection

Core Design Contradiction:

Length of moving objectVSReliability

Solution Approach 1:

The patent introduces a fitting as an intermediary component between the needle and housing. This fitting receives the needle tip and provides sealing through its internal geometry, while its external geometry allows insertion into the housing cavity. The fitting acts as a mediator that ensures reliable sealing without requiring the needle to directly seal against the housing, thus maintaining both short fluidic path and reliable sealing.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent employs a nested arrangement where the needle tip is received within the fitting cavity, and the fitting itself is inserted into the housing cavity. This nested structure (needle within fitting within housing) allows for compact integration while maintaining sealing at each interface, achieving both minimal fluidic path length and reliable sealing.

Inventive Principle:

Principle #7Nested doll (Nesting)

Data Source

PatentUS12507925B2Sampling with fitting between needle and housing

Publication Date: 2025.12.30 AGILENT TECHNOLOGIES INC

AI summary

A sampling unit includes a needle for aspirating a sample fluid, a housing, and a fitting. The needle includes a needle tip and a needle channel through the needle for guiding the aspirated sample fluid. The needle channel opens at the needle tip. The housing includes a housing cavity and a housing channel opening into the housing cavity. The fitting includes a fitting cavity and a fitting channel. The fitting is configured for sealingly receiving the needle tip into the fitting cavity and for being inserted into the housing cavity, so that the fitting channel on one side fluidically couples to the needle channel and on another side couples to the housing channel.