Rotating Carousel Spray System for Leather Uniformity

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Solution Overview

Problem

Current spray-painting systems for tannery leathers often result in non-uniform color distribution, with more paint applied to lateral areas than the central area, requiring multiple passes through the booth and increasing processing time and cost without ensuring complete surface uniformity.

Innovation Solution

The system increases the flow rate of the paint mixture during specific arcs of the circumference where the central area of the leather is positioned by using two pressure circuits for each spraying gun, one at low and one at high pressure, which are selectively activated to ensure uniform coverage across the entire surface.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If a single pressure circuit is used for spraying paint on leather, then the device complexity is reduced, but the painting uniformity deteriorates with lateral areas receiving more paint than the central area

Engineering Contradiction:
Improvepainting uniformityVSAvoidpressure circuit configuration
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The single pressure circuit is segmented into two separate pressure circuits (first pressure circuit and second pressure circuit) with different pressure levels. This segmentation allows independent control of paint flow to different regions of the leather, enabling uniform paint distribution across lateral and central areas while maintaining manageable system complexity through modular circuit design.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Different pressure levels are applied to different spatial regions of the leather surface. The first pressure circuit supplies paint at a first pressure level to lateral areas, while the second pressure circuit supplies paint at a second pressure level to the central area. This local quality approach ensures that each region receives the appropriate paint flow rate for uniform coverage, resolving the non-uniformity issue without requiring overly complex global control systems.

Inventive Principle:
Principle #3Local quality

2Manufacturing precision

If multiple passes through the painting booth are performed, then the painting uniformity is improved, but the processing time increases

Engineering Contradiction:
Improvesurface uniformityVSAvoidprocessing time
Core Design Contradiction:
Manufacturing precisionVSLoss of time

Solution Approach 1:

The system performs preliminary action by pre-configuring two pressure circuits with different pressure levels before the painting process begins. This preliminary setup enables the system to achieve uniform paint distribution in a single pass, eliminating the need for multiple repetitive passes through the painting booth and thereby reducing processing time while maintaining surface uniformity.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The system changes the pressure parameter of the paint supply circuits to optimize painting uniformity. By adjusting the pressure levels in the two circuits (first pressure level and second pressure level), the system achieves uniform paint application across different leather regions in one pass, avoiding the time loss associated with multiple passes at standard pressure settings.

Inventive Principle:
Principle #35Parameter changes

3Device complexity

If the spray painting system uses standard pressure for all areas, then the device complexity is minimized, but the paint distribution uniformity deteriorates

Engineering Contradiction:
Improvepressure control systemVSAvoidpaint distribution uniformity
Core Design Contradiction:
Device complexityVSManufacturing precision

Solution Approach 1:

The pressure control system is made dynamic by implementing two distinct pressure circuits that can independently adjust pressure levels. The first pressure circuit operates at a first pressure level for lateral areas, while the second pressure circuit operates at a second pressure level for the central area. This dynamic pressure control achieves uniform paint distribution without requiring overly complex multi-parameter control systems.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The system adds a pressure dimension to the paint supply system by creating two pressure levels instead of using a single pressure for all areas. This dimensional change in pressure control enables uniform paint distribution across different spatial regions of the leather while keeping the overall device complexity manageable through a relatively simple dual-circuit architecture.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

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 highly uniform paint distribution from the edges to the center of the leather, improving the final product quality and reducing the need for multiple passes through the booth.

Implementation Method 1

a plurality of fixed guns, which are installed at the ends of the arms and which atomize and spray the colored painting on the leather's surface to be painted

Methodology Applied
Scientific EffectAtomization:

Implementation Method 2

a compressed air circuit provides for a suitable paint atomization

Methodology Applied
Scientific EffectCompressed air flow:

Data Source

PatentEP2953726B1System and method for an external treatment of tannery leathers
Publication Date: 2018.10.10 ERRETRE
  • EP2953726B1 patent drawingFigure 1~2

AI summary

A method for an external treatment of tannery leathers (10) comprising the steps of positioning a leather (10) on a conveyor belt (12), which is able to drag the leather (10) within a spray booth, and of spraying a mixture, such as paint or color, onto the leather (10), inside the booth, by means of a plurality of spraying guns installed on respective arms of a rotating carousel. The spraying guns rotate along a prefixed circumference (C) during the traveling of the leather (10) on the conveyor belt (12) and each spraying gun is on in correspondence of two arcs (13, 14) of said circumference (C) during a complete rotation of the gun along said circumference (C). In particular, in correspondence of at least one portion of at least one of said arcs (13, 14) of circumference (C), the pressure of the sprayed mixture is increased, in order to obtain a highly uniform deposition of said mixture on the leather (10), as from the side edges of the leather (10) lying on the conveyor belt (12) up to a central area of said leather (10).