DIVELIME - Soda lime products for rebreather diving

About DIVELIME

DIVELIME is the European distributor for Intersurgical’s carbon dioxide (CO2) absorbent products aimed at rebreather diving – Intersorb® 812 and Spherasorb® 408.

Intersurgical is a UK based manufacturer of soda lime products for medical markets and have now developed Intersorb® 812 and Spherasorb® 408 products for rebreather diving. Premier Chemicals’ subsidiary, DIVELIME, is currently the sole distributor of Intersurgical’s diving grade products within Europe.

Rebreather diving

Diving with a rebreather differs from regular scuba diving in that the gas which is exhaled by the diver is recycled. Semi-closed rebreathers (SCR) partially recycle the gas whereas closed-circuit rebreathers (CCR) recycle the gas completely.

This means that rebreather diving makes more efficient use of the diving gas compared with scuba, and there is a smaller flow of bubbles into the surrounding water (in the case of SCR) or no bubbles at all (in the case of CCR).

Regular scuba diving is referred to as open circuit (OC) diving, and the diver exhales directly into the surrounding water creating many more bubbles than rebreather diving.

In order for the exhaled gas to be recycled within a diving rebreather, the carbon dioxide (CO2) produced during breathing needs to be removed to prevent the CO2 level within the breathing circuit from building up to dangerous levels. Soda lime granules are the most common method for removing the CO2 from the breathing circuit. The soda lime is contained in an absorber unit (often described as the ‘scrubber’) within the breathing circuit.

Soda lime

Soda lime is a chemical absorbent, containing mainly calcium hydroxide - Ca(OH)2 – and water. The calcium hydroxide reacts with the CO2 in the breathing circuit to form calcium carbonate which is retained within the absorber unit.

The quantity and grade of soda lime used will have an effect on how long the soda lime will last within the system.

Soda lime is generally graded by the particle size of the individual granules. In general, for a given volume of soda lime, a smaller particle size material will last longer than a larger particle size material.