Rotary Atomizing Head Housing Insulation for Condensation Control
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Solution Overview
Problem
Rotary atomizing head type coating machines face issues with moisture condensation on housing surfaces due to cooling by cold exhaust air, leading to voltage leaks and coating defects, especially when operating in high humidity environments.
Innovation Solution
Incorporation of a heat insulating air passage around the exhaust air passage to prevent cooling of the housing, using heat insulating air that is higher in temperature than the exhaust air, thereby preventing moisture condensation and ensuring a satisfactory finish.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If turbine air pressure is increased to raise turbine speed for spraying highly viscous paint, then paint atomization quality is improved, but exhaust air temperature drops due to adiabatic expansion causing moisture condensation on housing surfaces
Solution Approach 1:
A heat insulating air passage is introduced as an intermediary element between the exhaust air passage and the housing. This passage carries heat insulating air that prevents the cold exhaust air from directly cooling the housing surfaces, thereby blocking the pathway that leads to moisture condensation while allowing the high-pressure turbine air to continue operating at required speeds
Solution Approach 2:
The cold exhaust air that would normally cause harmful cooling is redirected through the heat insulating air passage. By positioning this cold air flow to surround the exhaust air passage rather than directly contact the housing, the system converts the potentially harmful cold air into a beneficial insulating layer that prevents moisture condensation on external housing surfaces
2Temperature
If exhaust air flows through the housing to cool the air motor, then motor temperature is controlled, but electrostatic coating operation becomes infeasible due to voltage leakage through condensed moisture
Solution Approach 1:
The heat insulating air passage acts as a thermal intermediary that separates the cold exhaust air from the housing surfaces. This allows the air motor to be cooled by exhaust air internally while preventing the housing external surfaces from reaching dew point temperatures that would cause moisture condensation and voltage leakage
Solution Approach 2:
Different thermal conditions are applied to different parts of the system: the air motor compartment allows cold exhaust air flow for cooling, while the housing external surfaces are protected by heat insulating air to maintain temperatures above dew point. This localized thermal management enables both motor cooling and electrostatic coating reliability
3Temperature
If housing surfaces are cooled by cold exhaust air, then air motor cooling is achieved, but coating quality degrades due to water droplet deposition on coated surfaces
Solution Approach 1:
The heat insulating air passage serves as a protective intermediary between the cold exhaust air and the housing external surfaces. This prevents the housing from becoming cold enough to cause water droplet formation in humid coating booth environments, thereby preventing water droplet contamination of the coated surfaces and maintaining coating quality
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 solution effectively prevents moisture condensation on housing surfaces, maintains electrostatic coating efficiency, and ensures high-quality coatings by isolating the housing from cold exhaust air, thus preventing voltage leaks and coating defects.
Implementation Method 1
a heat insulating air passage located in the housing in such a way as to extend along and around outer periphery of the exhaust air passage, said heat insulating air passage carrying heat insulating air of a higher temperature as compared with the exhaust air of the air motor
Implementation Method 2
an abrupt drop in temperature occurs due to adiabatic expansion when turbine air of high pressure and high temperature is introduced into a turbine chamber
Implementation Method 3
moisture condensation or sweating is very likely to occur on housing surfaces in a coating booth of high temperature and humidity
Data Source
AI summary
A rotary atomizing-head type coating machine, wherein a paint passage for flowing a paint to a rotary atomizing-head, a turbine air passage flowing a turbine air to the turbine of an air motor, a discharge air passage for flowing the turbine air after driving the turbine to the outside in the form of a discharge air, and a heat insulating air discharge passage of a heat insulated air passage axially extending while surrounding the discharge air passage and allowing hot heat insulated air to flow therein are formed in the bottom part of a housing body forming a housing. Thus, even if the turbine air expanded in a heat insulated state and reduced in temperature flows in the discharge air passage, the housing can be prevented from being cooled by the discharge air by flowing a heat insulated air with a temperature higher than that of the discharge air in the heat insulated air discharge passage.