Calculation method of residual gas volume in Oxygen cylinder:

Residual gas volume in Oxygen cylinder = volume of cylinder (L) * residual pressure in Oxygen cylinder (MPA) * 10 (coefficient)

For example: for a 2L Oxygen cylinder, when the residual pressure in the Oxygen cylinder is 10MPa, the remaining gas volume in the Oxygen cylinder is 2 * 10 * 10 = 200L

Note: the residual pressure in the Oxygen cylinder can be checked through the pressure reducing valve!