Diving Air Compressor - Gas Blending

Gas Blending

Compressors are often linked to a gas blending panel so nitrox, trimix, heliair or heliox mixes can be created. The panel controls the decanting of oxygen and helium from cylinders bought from commercial gas suppliers.

As it is not possible to decant to a diving cylinder from a storage cylinder that holds gas at a lower pressure than the diving cylinder, the expensive gas in low pressure storage cylinders is not easily consumed and may go to waste when the storage cylinder is returned to the supplier. The cascade system is often used with a bank to economically consume these high cost gases so that the maximum possible gas is removed from the bank. This involves filling a diving cylinder by first decanting from the bank cylinder with the lowest pressure that is higher than the diving cylinder's pressure and then from the next higher-pressure bank cylinder in succession until the diving cylinder is full. The system maximizes the use of low-pressure bank gas and minimizes the use of high-pressure bank gas.

Another method for scavenging expensive low pressure gases is to pump it with a Haskel pump or other gas booster pump.