Water-Based Paint Coating Chamber Dew Point Control

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Solution Overview

Problem

Ambient air flowing into coating devices for water-based paint applications can cause excessive moisture removal, leading to increased viscosity and undesired drying of the paint within the device.

Innovation Solution

The method involves determining the dew point in the coating device's application chamber and humidifying the ambient air to maintain a dew point above the minimum processing temperature of the paint, preventing excessive water evaporation and ensuring paint viscosity remains manageable, while also cooling the paint to prevent absorption of water from the air.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If ambient air flows into the coating device for coating operation, then the coating device can operate with normal air exchange, but the ambient air extracts water from the water-based paint causing viscosity increase and undesired drying

Engineering Contradiction:
Improveair exchange in coating deviceVSAvoidpaint viscosity stability
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The patent controls the dew point parameter of the ambient air to prevent excessive water evaporation from the paint. By maintaining the dew point above the minimum processing temperature, the humidity of the air is regulated, which prevents the paint viscosity from increasing too much during the coating process.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent uses a dew point sensor to continuously monitor the dew point in the coating device and feeds this information back to a control unit. The control unit adjusts the humidification of the ambient air based on the measured dew point, ensuring that the dew point remains above the minimum processing temperature and preventing paint drying.

Inventive Principle:
Principle #23Feedback

2Reliability

If the dew point in the coating device is increased by humidifying the ambient air, then water evaporation from the paint is reduced, but energy consumption for humidification increases

Engineering Contradiction:
Improvepaint viscosity stabilityVSAvoidenergy for humidification
Core Design Contradiction:
ReliabilityVSUse of energy by moving object

Solution Approach 1:

The control unit receives continuous feedback from the dew point sensor and adjusts the humidification only when necessary to maintain the dew point above the minimum processing temperature. This feedback-based control prevents unnecessary humidification and optimizes energy consumption while ensuring paint viscosity stability.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The patent dynamically adjusts the dew point parameter based on actual conditions in the coating device. By controlling the dew point to be just above the minimum processing temperature rather than maintaining a constantly high dew point, the system achieves paint protection with minimized energy consumption for humidification.

Inventive Principle:
Principle #35Parameter changes

3Reliability

If the paint is cooled to prevent water absorption from air, then paint viscosity stability is improved, but the paint temperature may fall below the minimum processing temperature

Engineering Contradiction:
Improvepaint viscosity stabilityVSAvoidpaint temperature
Core Design Contradiction:
ReliabilityVSTemperature

Solution Approach 1:

The patent converts the potentially harmful effect of cooling (which could drop paint temperature below minimum processing temperature) into a beneficial effect by precisely controlling the cooling process. The cooling is applied to reduce water evaporation and stabilize viscosity, but is monitored and controlled to ensure the paint temperature remains above the minimum processing temperature, thus converting a potential harm into a benefit.

Inventive Principle:
Principle #22Blessing in disguise (Convert harm into benefit)

Solution Approach 2:

The control unit monitors both the dew point and paint temperature, and adjusts the cooling process based on feedback from these measurements. This ensures that the paint is cooled enough to prevent excessive water evaporation and viscosity increase, but not so much that the temperature drops below the minimum processing temperature required for proper coating application.

Inventive Principle:
Principle #23Feedback

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 effectively reduces the risk of paint drying within the coating device, maintaining a stable viscosity and ensuring reliable paint application by controlling the dew point and temperature, thereby enhancing process reliability and preventing paint hardening.

Implementation Method 1

the dew point in the coating device, in particular in the application chamber, is determined. For a given air pressure, the dew point indicates the temperature below which water can condense from the air

Methodology Applied
Scientific EffectCondensation: Condensation

Implementation Method 2

the ambient air is humidified as a function of the dew point determined. By humidifying the ambient air, the dew point in the coating device can be increased

Methodology Applied
Scientific EffectEvaporation: Evaporation

Implementation Method 3

the paint in the coating device is cooled as a function of the dew point determined. Cooling the paint in the coating device can promote condensation and/or reduce the absorption of water from the paint into the air

Methodology Applied
Scientific EffectHeat transfer: Conduction (thermal)

Data Source

PatentEP3769853B1Coating device for coating a workpiece with a water-dilutable paint and method for operating such a device
Publication Date: 2023.04.05 JOSEF SCHIELE OHG
  • EP3769853B1 patent drawingFigure 1

AI summary

The invention relates to a method for operating a coating device (2) for coating a workpiece (1) with a water-based lacquer, wherein ambient air from the environment of the coating device (2) flows into the coating device (2), in particular into an application chamber (3) of the coating device (2), wherein a dew point in the coating device (2), in particular in the application chamber (3), is determined, and wherein the ambient air is humidified depending on the determined dew point such that a dew point is established above a minimum processing temperature of the water-based lacquer.Furthermore, the invention relates to a coating device (2) for coating a workpiece (1) with a water-based lacquer, with a device (13) for generating a negative pressure in the coating device, in particular in an application chamber of the coating device, an opening (12) through which ambient air from the environment of the coating device (2) can flow into the coating device (2), in particular into the application chamber (3), a control device (5) which is configured to determine a dew point in the coating device (2), in particular in the application chamber (3), and an air humidification device (4) for humidifying the ambient air depending on the determined dew point, so that a dew point is established above a minimum processing temperature of the water-based lacquer.