Solvent Dispensing Redesign: Reducing PPE Reliance with ATEX-Compliant Turnkey Solution

Project Overview

The client initiated a project to improve solvent handling and reduce reliance on PPE during the dispensing process of an existing OSD coating make-up system.

Several companies were invited to propose solutions. Epsilon was awarded the project and tasked with delivering a complete turnkey solution. Working closely with our clients, we proposed numerous improvements before designing a fully ATEX-compliant dispensing system that eliminated the need for PPE entirely.

Technical Challenges

One of the materials had a strict operator exposure limit (LTEL 8hr: 100ppm), requiring a tightly controlled, uninterrupted process. Two volatile solvents needed to be accurately dispensed into a mobile GMP make-up vessel from 220L drums, with two drums (duty/standby) per solvent.

Scope of Work

• Double diaphragm pumps with dual isolation valves and dip tubes (duty/standby) for each solvent
• Support structure for dip tubes, with integrated fume extraction and dedicated fan
• High and low flow dosing valves for precision dispensing
• Integration with supplied weigh scale and safe-area mounted printer
• Earth proving equipment and LEL (Lower Explosive Limit) monitoring
• Siemens PLC & ATEX HMI batch dispensing control system designed, built and programmed in house to GAMP5.

Design Considerations

Each drum featured bespoke dip tubes with air breathers, allowing air ingress during emptying while preventing vapour release. Dip tubes were mounted on lifting mechanisms that self-centered for precise placement, allowing safe connection to the dispensing manifold without affecting the weigh balance.

Operators input solvent mass via an in-house designed HMI and graphics interface. The system preloaded the set quantity and used air-driven pumps and two-stage valves (high/low flow) to achieve accuracy within 10 grams.

Safety Measures

To prevent ignition risk, the system included earth monitoring and interlocks to ensure pumps operated only when drums were properly grounded. The process vessel could only be filled when also earthed.

All four solvent drums were housed beneath a custom fume extraction cabinet. Each dip tube was mounted on pneumatic cylinders with raise/lower and centre-locking control functions.

Commissioning and Testing

The complete dispensary setup was fully assembled at Epsilon's facility for internal stress testing prior to Factory Acceptance Testing (FAT) witnessed by the client. This approach significantly reduced on-site commissioning and IOQ durations.

The final system was installed, commissioned, and qualified within the client's newly refurbished solvent dispensary area.

Outcome

The project delivered a safe, precise, and PPE-free solvent dispensing process in full compliance with ATEX and GMP standards. It also significantly improved operational safety and efficiency for the client's coating operations.