Boyle's law of the gas, and "k" is a constant. The equation states that the product of pressure and volume is a constant for a given mass of confined gas and this holds as long as the temperature is constant. For comparing the same substance under two different sets of conditions, the law can be usefully expressed as The equation shows that, as volume increases, the pressure of the gas decreases in proportion. Similarly, as volume decreases, the pressure of the gas increases. The law was named after chemist and physicist Robert Boyle, who published the original law in 1662. This relationship
Rebreather in the loop approximately constant and reduce gas consumption. A fully depth compensated system will discharge a volume of gas, inversely proportional to pressure, so that the volume discharged at 90m depth (10 bar absolute pressure) will be 10% of the surface discharge. This system will provide an approximately fixed oxygen fraction regardless of depth, when used with the same make-up gas, because the effective mass discharge remains constant. Partially depth compensating systems are part way between the fixed ratio and the depth compensating systems. They provide a high discharge ratio near the surface, but the discharge ratio is not