Gravity Cup Vent Membrane for Leak-Free Paint Spraying

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Solution Overview

Problem

Existing gravity-feed cups for paint spray guns suffer from air ingress leading to liquid escape during painting, especially when rapid movements are made, causing contamination and requiring re-treatment of surfaces.

Innovation Solution

A gravity-feed cup with an air-permeable, liquid-tight membrane in the ventilation opening ensures pressure equalization while preventing liquid escape, using materials like polysulfones or porous membranes to allow air flow without allowing liquid to pass.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a ventilation opening is provided in the gravity-feed cup to allow air flow for pressure equalization, then pressure equalization is improved, but liquid can escape through the ventilation opening during rapid movements or overhead painting

Engineering Contradiction:
Improvepressure equalizationVSAvoidliquid escape
Core Design Contradiction:
ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The patent applies a porous membrane material in the ventilation opening that allows air molecules to pass through while blocking liquid molecules. The porous structure provides sufficient pore size for air flow to maintain pressure equalization, while the hydrophobic properties and surface tension effects prevent liquid penetration, thus resolving the contradiction between ventilation reliability and liquid containment.

Inventive Principle:
Principle #31Porous materials

Solution Approach 2:

The ventilation opening uses a composite structure combining a porous membrane layer with a hydrophobic coating. This composite material integrates the breathability of porous materials with the liquid-repelling properties of hydrophobic surfaces, achieving both effective air ventilation and liquid prevention in a single component.

Inventive Principle:
Principle #40Composite materials

2Object-generated harmful factors

If a membrane is introduced to prevent liquid escape while allowing air flow, then liquid containment is improved, but device complexity increases

Engineering Contradiction:
Improveliquid containmentVSAvoidventing device structure
Core Design Contradiction:
Object-generated harmful factorsVSDevice complexity

Solution Approach 1:

The patent employs a porous membrane that inherently provides both ventilation and liquid containment functions through its material properties alone. This single-component solution avoids the need for complex mechanical valves or multiple sealing elements, thereby maintaining simplicity while achieving the desired liquid containment.

Inventive Principle:
Principle #31Porous materials

Solution Approach 2:

The porous membrane automatically adapts to pressure differentials and flow conditions without requiring external control mechanisms. The membrane self-regulates air and liquid flow based on its inherent material properties, eliminating the need for additional actuators, sensors, or control systems that would increase device complexity.

Inventive Principle:
Principle #25Self-service

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 maintains pressure equalization and prevents liquid leakage during painting and storage, ensuring clean operations and reducing the need for surface re-treatment.

Implementation Method 1

a ventilation device (4, 6) is provided in the gravity-feed cup (1), which comprises a membrane (4) that closes the ventilation opening (6) in an air-permeable and liquid-tight manner

Methodology Applied
Scientific EffectPermeation: Permeation

Implementation Method 2

using materials like polysulfones or porous membranes to allow air flow without allowing liquid to pass

Methodology Applied
Scientific EffectPorosity: Porosity

Implementation Method 3

a membrane (4) that closes the ventilation opening (6) in an air-permeable and liquid-tight manner

Methodology Applied
Scientific EffectSurface tension: Surface Tension

Data Source

PatentEP4013549B1Gravity cup for a paint spray gun
Publication Date: 2026.03.18 SATA GMBH & CO KG
  • EP4013549B1 patent drawingFigure 1
  • EP4013549B1 patent drawingFigure 2
  • EP4013549B1 patent drawingFigure 3~4

AI summary

The invention relates to a gravity cup for a paint spray gun comprising a container (1) and a cover (2) that can be placed on the container and a connecting part (3) by means of which the gravity cup can be placed on the paint spray gun or an adapter, the gravity cup having a ventilation device with a ventilation opening (6). In or on the ventilation opening (6) an air-permeable and at the same time liquid-tight membrane (4) is located and seals the ventilation opening (6) from any liquid.