## Bottled oxygen bottle volume calculation method

How long will the oxygen in the cylinder last?

At the end of this topic, I will give a chart showing you, how long an oxygen cylinder may last when used continuously.

There are mainly two ways of calculating this value. (oxygen bottle volume)

Suppose you have an E-type oxygen cylinder. It generally consists of 1000 liters of oxygen. Now, as per your doctor’s prescription, you might be using oxygen at the rate of 3 liters/min (i.e 180 liters/hour). Then total time to evacuate the cylinder = 1000 liters/ 180 liters per hour = 5.55 hrs.

Sometimes, the oxygen may not have been refilled to the point where it should have been. In that case, the above calculation will give you an error. So, instead of following the above method, you can follow this formula to calculate the value.

Step one: Know the pressure exerted by the oxygen to the oxygen cylinder. You will find it in the cylinder or else ask the manufacturer. You can also check it with the help of a pressure gauge.

Step two: Subtract 200 psi from the given pressure. This is due to the assumption that about 200 psi of oxygen is left in the cylinder. Or, in other words, we should not use a cylinder if the pressure shown by the pressure gauge goes below 200 psi.

Step three: Multiply the above value with the cylindrical constant. (oxygen bottle volume)

Cylinder type | Cylindrical Constant |

D | 0.16 |

E | 0.28 |

M | 1.56 |

G | 2.41 |

H and K | 3.14 |

Step four: Divide the obtained value with the flow rate that has been prescribed to you by the doctor.

### Bottled oxygen bottle volume calculation method

When we use bottled oxygen, the oxygen is compressed gas under high pressure. What is the volume of this bottle of oxygen at standard atmospheric pressure?

After measuring the gas pressure in the bottle, it can generally be approximated by the following formula

V≈V1*P/0.098

V—The volume of gaseous oxygen in the bottle (L)

V1—Water volume of steel cylinder (L)

P —The pressure of oxygen in the bottle (MPa)

Example: Suppose the water volume of the oxygen cylinder is 40L, and the oxygen pressure in the bottle at 20°C after filling is 14.7MPa, then according to the above formula:

V≈40*14.7/0.098=6000L=6m3

When the oxygen in the cylinder has been used for a period of time, if you want to estimate the volume of the remaining oxygen in the cylinder, you can use the following formula: V/≈(P/+0.1) V1/0.098 (oxygen bottle volume)

V/—The volume of remaining oxygen in the bottle (L)

P/—Indicating pressure of gas cylinder pressure reducer high pressure gauge (MPa)

V1—The water volume of the cylinder (L)

Example: Suppose the water volume of the oxygen cylinder is 40L, the oxygen pressure in the cylinder after a period of use is 0.8MPa, and the volume of remaining oxygen in the cylinder can be obtained according to the above formula:

V/≈(0.8+0.1)*40/0.098=367L=0.367m3

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