Multi-Stage Counterflow Dryer for High-Speed Inkjet Web Presses

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Solution Overview

Problem

High-speed inkjet web presses require higher water content inks, which increase the need for higher capacity dryers, but existing solutions fail to efficiently increase drying capacity without increasing the size and cost of the press.

Innovation Solution

A multi-stage counterflow dryer is developed, where each successive stage reheat and reuse air to expose the web to increasing humidity, utilizing multiple smaller blowers for better airflow control, promoting efficient heat and mass transfer.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If higher water content inks are used to support fast printing speeds, then printing productivity is improved, but drying capacity requirements increase leading to larger and more expensive dryer systems

Engineering Contradiction:
Improveprinting speedVSAvoiddryer size
Core Design Contradiction:
ProductivityVSVolume of stationary object

Solution Approach 1:

The dryer is divided into multiple stages (typically 3-5 stages) with each stage having its own blower and heater. This segmentation allows independent control of air flow and humidity at each stage, enabling efficient drying of high water content inks without requiring a single large-capacity dryer system.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The system dynamically adjusts air flow rate, temperature, and relative humidity parameters across different dryer stages. By controlling these parameters independently at each stage, the system optimizes drying efficiency for high water content inks while maintaining compact dryer dimensions.

Inventive Principle:
Principle #35Parameter changes

2Productivity

If higher water content inks are used to support fast printing speeds, then printing productivity is improved, but the cost of the dryer system increases

Engineering Contradiction:
Improveprinting speedVSAvoiddryer system cost
Core Design Contradiction:
ProductivityVSEase of manufacture

Solution Approach 1:

The dryer is divided into multiple stages (typically 3-5 stages) with each stage having its own blower and heater. This segmentation allows independent control of air flow and humidity at each stage, enabling efficient drying of high water content inks without requiring a single large-capacity dryer system.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The system dynamically adjusts air flow rate, temperature, and relative humidity parameters across different dryer stages. By controlling these parameters independently at each stage, the system optimizes drying efficiency for high water content inks while maintaining compact dryer dimensions.

Inventive Principle:
Principle #35Parameter changes

3Device complexity

If conventional single-stage dryers are used, then device complexity is low, but drying efficiency is insufficient for high water content inks

Engineering Contradiction:
Improvedryer structureVSAvoiddrying capacity
Core Design Contradiction:
Device complexityVSProductivity

Solution Approach 1:

The dryer is divided into multiple stages (typically 3-5 stages) with each stage having its own blower and heater. This segmentation allows independent control of air flow and humidity at each stage, enabling efficient drying of high water content inks without requiring a single large-capacity dryer system.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The system dynamically adjusts air flow rate, temperature, and relative humidity parameters across different dryer stages. By controlling these parameters independently at each stage, the system optimizes drying efficiency for high water content inks while maintaining compact dryer dimensions.

Inventive Principle:
Principle #35Parameter changes

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 configuration enhances drying efficiency by reusing heat and optimizing air humidity, reducing the size and operational costs of high-speed inkjet web presses while effectively handling higher water content inks.

Implementation Method 1

Each stage includes a heater configured to heat the air to a high temperature

Methodology Applied
Scientific EffectHeating: Heating

Implementation Method 2

Each stage includes a blower configured to move the air across the web

Methodology Applied
Scientific EffectForced Convection: Forced Convection

Implementation Method 3

the web is moved through the dryer to dry the ink

Methodology Applied
Scientific EffectEvaporation: Evaporation

Data Source

PatentEP3038831B1Variable humidity drying
Publication Date: 2020.03.18 HEWLETT PACKARD DEVELOPMENT COMPANY LP
  • EP3038831B1 patent drawingFigure 1
  • EP3038831B1 patent drawingFigure 2
  • EP3038831B1 patent drawingFigure 3

AI summary

In one example, a multi-stage hot air dryer in which each successive stage is configured to take in air discharged from a prior stage and discharge it on to an article moving through the dryer from the last stage to the first stage such that the article is exposed to higher humidity air first in the dryer and to lower humidity air last in the dryer.