How to discharge a High Potent API from a filter dryer?

March 28, 2022
  • How to discharge a High Potent API from a filter dryer?
  • How to avoid work injury when opening & cleaning the base plate?
  • Can milling be integrated in the isolator?

Here is a solution proposed by FPS:


Discharge High Potent API (CPT < 50ng/m3) from a 0,5m2 filter dryer, sample, disassemble and clean.

What are the issues?

  • The API is highly toxic (CPT < 50ng/m3)
  • Large & heavy filter dryer to integrate in an isolator
  • Risk of work injury to open & move the heavy the filter base plate for cleaning and maintenance
  • Risk of work injury when filter dryer is hot or when agitator is running
  • ATEX classified installation room (II 2G) and isolator chambers (II 2GD)
  • Oxygen level inside the isolator shall never exceed 4%

Process steps:

  • Introduce tools through the inlet airlock
  • Move the tools to the filter dryer chamber
  • Discharge the filter dryer (bottom of the filter dryer is inside the isolator)
  • Perform the product sampling
  • Move the product to the milling chamber, mill, weigh and dispense
  • Move the milled product to the outlet airlock
  • Take the product out of the isolator  
  • Disassemble the filter base plate + all of its components and clean

Benefits of FPS Solution:

  • Sturdy: supporting structure of the isolator designed to bear the heavy weight and absorb vibrations
  • Tight connection: ceiling of the filter dryer chamber fitted with custom flange for coupling with filter dryer
  • Ergonomic: rails move the filter base plate (no heavy lifting by operators)
  • Flexible: short track (remove product directly) or longer track (mill and dispense first then discharge)
  • Safe: protection bars with safety switches prevent access when filter dryer is hot or agitator is running

Description of FPS custom solution:

The isolator is composed of 4 chambers:

  • an inlet airlock, where the tools are introduced
  • a filter dryer chamber where the filter base plate is accessed for discharge, sampling, cleaning and maintenance activities
  • a milling chamber where a conical mill and a weight scale are provided for product milling and dispensing
  • an outlet airlock for the final product removal

The filter dryer chamber has a cut-out with a counter-flange on the ceiling that is matched with the flange on the ANFD so that only the bottom of the filter dryer is inside the isolator. When the ANFD is running, glove bars prevent the operators from accessing the chambers. At the end of the process, the discharge hatch is manually opened through the gloves and the product is discharged with a special rack. At the end of the operations, the filter base plate can be lowered and can roll on custom designed rails to perform ordinary or extraordinary maintenance.

Inside the milling chamber a conical mill and a weight scale are provided for product milling and dispensing. Both the ANFD and the milling chamber communicate with the outlet airlock and their connection doors are fitted with continuous liner systems to keep contamination to a minimum.

Outlet ventilation lines have oxygen sensors to ensure that the chambers are inert. In case of oxygen concentration higher than the threshold, the electrical supply to non-ATEX rated process equipment is temporarily suspended.

Custom solution highlights:

  • Special design of the filter dryer chamber:
    • Rails used to support and move the filter base plate for maintenance
    • Unconventional design to guarantee optimal access to the process equipment
  • Three inlet ventilation lines are provided for each chamber
    • High nitrogen flow for rapid inertization
    • Low nitrogen flow for the operations
    • Compressed air flow to remove quickly the nitrogen at the end of the operations
  • Internal doors fitted with continuous liner systems to guarantee highest containment performances