Oxygen Concentrators - Refilling Sieve Beads in Cartridges

The purpose of the document is to provide suggestions for how someone might refill the sieve beads in the molecular sieve cartridges for an oxygen concentrator. It is recommended that only qualified operators perform this task. This document is only provided for reference purposes to help increase knowledge and reduce problems or issues for someone who might be attempting to refill their own sieve beads.

Preparing the Molecular Sieve Cartridge for Refill

1. Inspect the integrity of the O-rings that are located in the top and bottom end caps. Replace these O-rings as necessary, but especially if there is any noticeable damage or wear.
2. There should be a paper-type filter located at the bottom of the sieve bed. It’s best to use a new filter when changing out the sieve beads. Be sure to cut off any excess material so that it fits as close to perfect as possible.
3. Once the O-rings are inspected and filter has been replaced, the cartridge is ready for reloading with sieve beads.

Filling the Molecular Sieve Cartridge

1. Begin by filling the cartridge with the new sieve material, leaving about 2-3 centimeters from filling it to the top.
2. Next, move the sieve cartridge to an agitator or vibrating plate and allow the material to settle and compact.
3. Once the material has settled, add more sieve material again, leaving about 2-3 centimeters from filling it to the top.
4. Place a filter plate on top of the sieve material in the cartridge and then place a bit of filter material on top of the filter plate.
5. Using the filter plate and material to cover the top of the cartridge, flip the cartridge horizontally and use the agitator to help compact the material. Press hard, inward on the top of the cartridge to help compact the material.
6. Begin rolling the cartridge across the agitator until it doesn’t seem like the material will compact and settle any further.
7. Set the cartridge back upright and remove the filter plate and filter material that was placed on the top of the cartridge.
8. Add more sieve material until there is about one half of an inch (1/2”) of free space remaining at the top of the cartridge.
9. Place two layers of the filter media on the top of the cartridge and press into place along with the upper filter plate. Trim any excess filter material.
10. Use an air compressor to blow any stray molecular sieve from the upper filter plate.
11. Repeat this method with any additional cartridges before continuing.

Assembly and Testing

1. Without using the muffler, place the bottom molecular sieve cartridge end cap on a table.
2. Place the two sieve cartridges on the bottom while ensuring that the O-rings do not move or fall out of the correct position.
3. While still ensuring the O-rings don’t move, replace the product canister to its position over the flapper.
4. Use one hand to hold the assembly while using the other hand to place the two springs onto the sieve cartridge, then putting the top cap, with the muffler, onto the sieve cartridge.
5. Use a wrench to hold the assembly then tighten the other end with another wrench (usually the same size). Ensure that the O-rings and springs do not move or fall out of place while tightening.  Make sure to completely close the assembly.
6. Test the purity of the oxygen concentrator to ensure acceptable purities are being generated with the new material and in the fashion through which the material was replaced.