Paint Filtration System for High-Solids Water-Based Coatings
Application Background
A client in the paint industry required a filtration system for high-solids water-based paint with the following process conditions:
· Application: Paint filtration
· Flow Rate: 6,000–8,000 L/h
· Media: Water-based paint with 75–80% solids content
· Required Filtration Accuracy: 250 μm
· Material of Construction: SS304
· Connections: 3-inch inlet and outlet flanges
For paint applications, especially high-solids coatings, filtration can be challenging due to the viscosity of the media and the tendency of pigments and resins to accumulate inside the filter element.
Based on our experience in the paint industry, we frequently recommend self-cleaning filters with a spiral scraper mechanism, which are specifically designed to handle viscous and high-solids liquids. However, in this case, the client preferred to use a manual bag filtration system.
Our Proposed Solution
To meet the client's requirements, we designed a two-stage filtration system consisting of two single bag filter housings mounted on a mobile skid.
First Stage
· Single bag filter housing
· Filtration rating: 400 μm
· Function: Removal of larger particles and agglomerates
Second Stage
· Single bag filter housing connected directly to the outlet of the first stage
· Filtration rating: 250 μm
· Function: Final filtration to achieve the required product quality
The complete skid included:
· Two SS304 single bag filter housings
· Pneumatic diaphragm pump
· Valves and piping
· Mobile trolley for easy movement and operation
· 3-inch flange connections
This staged filtration design reduces the solids loading on the finer filter and improves overall filtration stability.
Client's Request for Filter Media
The client preferred not to use filter bags and requested a reusable solution. To accommodate this requirement, we recommended sintered mesh filter elements as a direct replacement for filter bags.
However, due to the characteristics of the process media, the application proved unsuitable for this type of filter element.
The Challenge
The sintered mesh cartridges feature a multi-layer structure. Although they are effective in many industrial applications, they are not ideal for very high-solids water-based paints.
After commissioning, the system operated for only about two minutes before the differential pressure increased rapidly and the pump automatically stopped.
Our investigation found that:
· The high-solids paint quickly blocked the fine pores inside the multi-layer sintered mesh.
· The blockage caused a rapid pressure rise and interrupted the filtration process.
· The issue was not related to equipment quality but to the incompatibility between the filter media and the characteristics of the paint.
This case highlights an important point in paint filtration:
Selecting the correct filter media is just as important as selecting the correct filter housing.
Our Response and After-Sales Support
After discussing the issue with the customer, we recommended returning to the proven solution for paint applications:
Perforated support basket + Nylon filter bag
This configuration offers several advantages:
· High dirt-holding capacity
· Lower pressure drop
· Better handling of high-solids and viscous paints
· Easy replacement and maintenance
· Lower operating costs
To minimize the client's downtime, we immediately arranged to provide replacement filter baskets free of charge and assisted the customer in converting the system back to bag filtration.
Take a look at the old filters that the client is using:
Our Experience in Paint Filtration
Paint filtration applications often involve:
· High viscosity
· High solids content
· Sensitive product quality requirements
· Frequent color changes and cleaning cycles
Our engineering team has extensive experience in selecting the appropriate filtration technology for these challenging conditions, including:
· Spiral scraper self-cleaning filters
· Bag filtration systems
· Basket filters
· Customized multi-stage filtration skids
More importantly, we stand behind our equipment with practical application support and responsive after-sales service. When process conditions change or unexpected issues arise, we work closely with our clients to identify the root cause and provide effective solutions quickly.
Good filtration is not only about supplying equipment—it is about understanding the process and supporting the client throughout the entire operatio