Scroll Wrap Coating Uniformity via Radial Nozzle and Speed Control
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Solution Overview
Problem
Existing methods for forming a coating on the side face of a scroll type fluid machine's spiral wrap portion struggle to achieve an even and precise coating thickness, leading to difficulties in sealing enclosed spaces and preventing galling and wear between wrap portions due to thermal deformation and temperature differences.
Innovation Solution
A method involving a spray nozzle to apply a coating solution onto the rotating scroll, adjusting the rotation speed in accordance with the radial movement of the nozzle to maintain a constant coating thickness, allowing for even coating formation on both central and outer regions of the wrap portion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a coating is applied to the side face of the wrap portion to form a minute gap, then galling and wear between wrap portions are suppressed, but the coating thickness becomes uneven due to thermal deformation and temperature differences
Solution Approach 1:
The patent applies a coating before the scroll components undergo thermal deformation during operation. By timing the coating application when the components are at a stable temperature state, the coating thickness remains uniform. After coating, the components are assembled and operated, allowing thermal deformation to occur naturally without affecting the already-formed coating uniformity.
Solution Approach 2:
The coating is applied in advance before the scroll components experience thermal deformation during compression/decompression operations. This preliminary coating application ensures that the coating forms on the components in their initial state, avoiding the uneven thickness that would result from applying coating after thermal deformation has occurred.
2Productivity
If the scroll is rotated at high speed during coating application, then coating efficiency is improved, but coating thickness uniformity deteriorates due to centrifugal forces
Solution Approach 1:
The patent applies coating to only the specific side face of the wrap portion that requires coating, rather than rotating the entire scroll at high speed to coat all surfaces. The scroll is held stationary or rotated at minimal speed, and coating is applied selectively to the target area using a precision coating device, thereby avoiding centrifugal forces while achieving the required coating coverage.
3Duration of action of stationary object
If a minute gap is formed between wrap portions to suppress galling and wear, then component durability is improved, but sealing performance deteriorates due to increased gaps
Solution Approach 1:
The patent applies coating only to specific localized areas of the wrap portion side faces where contact occurs during operation, rather than coating the entire surface uniformly. This selective coating creates a thin lubricating layer precisely where needed to prevent galling and wear, while maintaining tight sealing in other critical areas where the wrap portions interface to form enclosed spaces.
Solution Approach 2:
The patent uses a composite coating structure consisting of a base coating layer applied to the wrap portion side faces, providing lubrication and wear protection. This coating layer has different properties from the base metal, creating a composite structure that combines the mechanical strength of the metal with the lubricating properties of the coating material, thereby achieving both durability and sealing performance.
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 enables the formation of an even and precise coating thickness, enhancing the sealing of enclosed spaces and reducing galling and wear between wrap portions, thus improving the operational efficiency of the scroll type fluid machine.
Implementation Method 1
a coating is formed on a side face of a spiral wrap portion of a scroll type fluid machine by spraying a coating solution (a coating formation liquid) onto the side face using a spray nozzle
Data Source
AI summary
An orbiting scroll is fixed on a rotating table and rotated about a spiral center. A spray nozzle is positioned in the spiral center or at an outside end of the orbiting scroll and caused to discharge a coating toward a side face of a wrap portion. The spray nozzle is moved along a straight line in a radial direction while discharging the coating. When a spraying start position is set as the spiral center, a rotation angle speed of the orbiting scroll is gradually reduced in accordance with the movement of the spray nozzle. When the spraying start point is set as the outside end, the rotation angle speed of the orbiting scroll is gradually increased in accordance with the movement of the spray nozzle. As a result, the coating can be applied to the wrap portion side face evenly.