Introduction
Oxygen cylinders are used to transport compressed oxygen gas. They are used in hospitals for artificially administering oxygen to patients. A good ambulance is always equipped with an oxygen cylinder refill to keep patients breathing while being carried to the hospital. Scuba divers and undersea explorers also have oxygen cylinders to assist with normal breathing. Patients with respiratory disorders like emphysema, asthma, and pneumonia are advised to keep an oxygen cylinder handy.
Background
Oxygen (atomic number 8; atomic weight, 16) is essential for all living things and can combine with almost all other elements. When elements fuse with oxygen, they are labeled as being oxidized. Oxygen is the most abundant element in the world, comprising about 90% of water (hydrogen makes up the other 10%) and 46% of the earth’s crust (silicon, 28%; aluminum, 8%; and iron, 5%, among others). Oxygen’s melting point is −360°F (−218°C), and its boiling point is −297°F (−183°C). In its free state, oxygen is odorless, colorless, and tasteless. At temperatures below −297°F (183°C), oxygen takes on a pale blue liquid form.
Two-thirds of the human body is composed of oxygen. In humans, oxygen is taken in through the lungs and distributed via the bloodstream to cells. In the cells, oxygen combines with other chemicals, making them oxidized. The oxidized cells are then distributed where needed, providing the body energy. The waste products of respiration are water and carbon dioxide, which are removed through the lungs.
Pressurized oxygen therapy treats numerous medical ailments such as emphysema, asthma, and pneumonia. This medicinal form of oxygen is typically kept in medium-sized aluminum canisters equipped with pressure regulators and release valves. In addition, large amounts of oxygen are kept in large, insulated steel tanks pressurized at 2,000 lb/in 2 (141 kg/cm 2 ).
How is oxygen made?
Oxygen is made in two ways:
Medical oxygen:
According to Air Liquide Sante France, medical oxygen is made by separating oxygen from other gases and impurities in the air by repeated compression, filtration, and purification steps.
Such medical oxygen reaches more than 99.5 percent purity and is rigorously tested.
It can be highly compressed into a liquid form but has to be maintained below -182°C, according to Air Liquide Sante France. This is the best way to meet variations in demand as one liter of liquid oxygen is equivalent to around 800 liters in standard gas form.
Canisters that can travel with patients with one liter of compressed oxygen contain about 200 liters of normal oxygen.
Compressed oxygen:
Compressed oxygen machines that separate nitrogen from ambient air can raise oxygen levels to around 93 percent. The devices can be portable or more significant to serve a hospital. However, these machines cannot meet surges in demand — which rose by a factor of five or six in French hospitals as waves of Covid patients peaked. In addition, they require lots of electricity and must be regularly maintained by a technician.
The World Health Organization, UNICEF, the World Bank, and other donors and NGOs have shipped hundreds of thousands of concentrators to hundreds of countries to help deal with surges in oxygen needs during the pandemic. Still, companies are now reporting shortages of parts.
Even when oxygen is available, there can be problems identifying patients with low oxygen levels. For example, in many countries, there are shortages of pulse oximeters – small devices clipped to the finger that measures oxygen levels in the blood – though this is something the aid agencies are sending along with other equipment.
