Pipe Section Coating via Segmented Plasma Zones

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Solution Overview

Problem

Existing methods for coating long, narrow pipes with corrosive-resistant materials like diamond-like carbon are limited by pressure drop and non-uniform plasma generation, leading to inadequate coating uniformity and reduced film deposition towards the exit.

Innovation Solution

The method involves isolating sections of the pipe using solid plates as entrance and exit points for gas flow, allowing for thermal or plasma activation, and using a hollow cathode environment to maintain a more intense and uniform plasma along the pipe length, reducing gas depletion and ensuring consistent coating thickness.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If CVD or PVD techniques are used to coat long, narrow pipes, then high quality films with good purity and adhesion can be achieved, but uniformity deteriorates due to pressure drops and gas depletion along the pipe length

Engineering Contradiction:

Improvefilm uniformityVSAvoidpipe length

Core Design Contradiction:

Manufacturing precisionVSLength of stationary object

Solution Approach 1:

The pipe is divided into multiple coating zones along its length, with each zone having independent gas flow control and plasma generation. This segmentation allows each zone to maintain optimal deposition conditions independently, preventing the gas depletion and pressure drop problems that occur in continuous long pipes, thereby achieving uniform coating thickness and quality throughout the entire pipe length.

Inventive Principle:

Principle #1Segmentation

2Manufacturing precision

If thermal CVD is used to coat long pipes, then coating can be applied to the internal surface, but heat-sensitive substrates are damaged due to high temperature requirements

Engineering Contradiction:

Improvecoating coverageVSAvoidsubstrate temperature

Core Design Contradiction:

Manufacturing precisionVSTemperature

Solution Approach 1:

A plasma field is introduced as an intermediary energy form to enable chemical vapor deposition at lower temperatures. The plasma activates the precursor gases and provides the necessary reaction energy without requiring high substrate temperatures, allowing coating of heat-sensitive substrates while maintaining good film quality and coverage.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Temperature

If PECVD is used to lower reaction temperature, then heat-sensitive substrates can be coated, but plasma uniformity deteriorates and source gas depletes along the pipe

Engineering Contradiction:

Improvereaction temperatureVSAvoidplasma uniformity

Core Design Contradiction:

TemperatureVSManufacturing precision

Solution Approach 1:

Inventive Principle:

Principle #1Segmentation

4Manufacturing precision

If PVD techniques are used for coating, then high quality films can be deposited, but the technique is limited to large diameter and short length tubes due to molecular flow region constraints

Engineering Contradiction:

Improvefilm qualityVSAvoidapplicable pipe dimensions

Core Design Contradiction:

Manufacturing precisionVSAdaptability or versatility

Solution Approach 1:

A plasma field is introduced as an intermediary to enhance the PVD process, allowing coating of long, narrow pipes. The plasma activates the deposition process and maintains sufficient reaction rates even in the molecular flow regime, extending the applicability to high aspect ratio pipes while maintaining film quality.

Inventive Principle:

Principle #24Intermediary (Mediator)

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 approach achieves uniform coating of long pipes by maintaining a stable plasma and precursor gas concentration, reducing the end-to-end decline in coating thickness and improving film quality, particularly for high aspect ratio workpieces.

Implementation Method 1

If a plasma sheath is conformal, the positive ions will be pulled toward the workpiece

Methodology Applied

Scientific EffectIon attraction: Ion Repulsion/Attraction

Implementation Method 2

Gas can be activated to coat the surface of the workpiece by thermal or plasma methods

Methodology Applied

Scientific EffectThermal activation: Heating

Implementation Method 3

Plasma enhanced CVD (PECVD) can be used to lower the temperature required for reaction

Methodology Applied

Scientific EffectPlasma enhanced chemical vapor deposition: Plasma Enhanced Chemical Vapour Deposition

Implementation Method 4

There are also improvements that can be made to film properties such as adhesion and film density via ion bombardment of the workpiece

Methodology Applied

Scientific EffectIon bombardment: Ion Beam

Data Source

PatentUS7608151B2Method and system for coating sections of internal surfaces

Publication Date: 2009.10.27 ARMORLUBE LLC

AI summary

A method and system for coating the internal surfaces of a localized area or section of a workpiece is presented. Conductive structures are inserted into one or more openings of a workpiece to define the section to be coated. In some embodiments, a bias voltage is connected to a workpiece section, which functions as a cathode. A gas source and vacuum source are coupled to each conductive structure through a flow control system. The flow control system enables a first opening to function as a gas inlet and a second opening to function as a vacuum exhaust. Only the section encompassed by the conductive structures is coated. When the coating process is completed, a means for varying the conductive structures along the length is utilized to move onto the next section to be coated.