by Jan Willem Bech | Vademecum
Oxygen from chemical reaction as a gas supply for oxygen rebreathers Oxygen rebreathers based on a chemical process are among the oldest types. The system uses chemicals that absorb CO2 and generate oxygen. As early as 1930, a whole series of devices under the name...
by Jan Willem Bech | Vademecum
Liquid oxygen as a gas supply for oxygen rebreathers Liquid oxygen has been used in breathing systems since the 1920s. The principle is relatively simple. Liquid oxygen has a temperature of approximately -185 degrees Celsius (-301 F) and will evaporate at room...
by Jan Willem Bech | Vademecum
Single bag type counterlung Most oxygen rebreathers use a simple single counter lung. Materials used in the early days are finely-woven fabrics, impregnated with rubber or latex. Later reinforced plastics where used. These plastics are commonly welded by induction...
by Jan Willem Bech | Vademecum
Split counterlungs Separate counter lungs for inhale and exhale are rarely used with oxygen systems. The reason for this is that oxygen systems are by far the most common in atmospheric conditions. For underwater use the diving depth is often limited and the...
by Jan Willem Bech | Vademecum
Dual hose configuration The most characteristic external feature is that a rebreather user uses a breathing hose with an inlet and an outlet. With the exception of oxygen rebreathers, almost all modern rebreathers have separate counter lungs and separate hoses for...
by Jan Willem Bech | Vademecum
Counterlung form and mechanism Counter lungs are in most cases made of flexible materials. In some special cases the designer chooses for a more rigid material. Sometimes counterweights are used to compensate the hydrostatic pressure difference. This technique...
by Jan Willem Bech | Vademecum
Sidemounted hoses and sidemount rebreathers This post is about the routing of breathing hoses. This technique has also created a special rebreather for underwater use, which is specifically used for narrow passages underwater. These are found mainly in caves and...
by Jan Willem Bech | Vademecum
Single hose or pendulum system Single hose systems are always pendulum systems. The original oxygen rebreather often had a single hose because this was constructively attractive. The disadvantage of this system is that the gas goes through the scrubber twice. This...
by Jan Willem Bech | Vademecum
Position of the counterlung; on the chest or on the back We distinguish different types of counterlungs used with rebreathers. On land, the choice of whether the counter-lung is worn on the chest or the back will make little difference to the breathing resistance....
by Jan Willem Bech | Vademecum
Valves in oxygenrebreathers operated by a demand valve In addition to the principle of dosing gas by activating a valve with a lever, we also know the on-demand principle. On the counter-lung, an automatic device (second stage principle) is mounted whereby a membrane...
by Jan Willem Bech | Vademecum
Cooling systems in rebreathers Cooling breathing gas in the loop For applications requiring entering a room with high temperatures or breathing for long periods from a closed system, the temperature in the breathing circuit can become higher. For this reason, since...
by Jan Willem Bech | Vademecum
Valves in oxygenrebreathers operated by the moving counterlung In 1920, the first rebreather was developed that operated with a then new mechanism. Until then, the supply of oxygen to the breathing circuit had been reserved for regulators that injected gas...
by Jan Willem Bech | Vademecum
Manual addition of oxygen in oxygen rebreathers The use of manual addition in oxygen rebreathers is the oldest form of adding oxygen to the loop. When the diver is breathing, the oxygen is metabolized and the counter lung volume will decrease. To keep the counter lung...
by Jan Willem Bech | Vademecum
Scrubber cartridge build in the counter lung Oxygen rebreathers are mainly used in the mining industry. Later, these systems were further developed for underwater use. The purpose of oxygen breathers for diving was primarily for military applications. The unique...
by Jan Willem Bech | Vademecum
Constant Mass Flow in Oxygen Rebreathers This part with the theory of oxygen rebreathers deals with the technical principle of a constant mass valve. This type of oxygen injection is widely used in breathing systems for oxygen, nitrox and trimix. Because this article...
by Jan Willem Bech | Vademecum
Constant Mass Flow Valves and Orifices theory I made this page because there were many questions in newsgroups about gas flow through an orifice. Many people are now developing manually operated constant-dosis rebreathers. Jan Jahns has written the article below. For...
by Jan Willem Bech | Vademecum
Both the fish and diver have a leaking loop…. This page deals with the various design aspects of rebreathers in general. The page is a living page and can be completed with knowledge of the readers. Your contribution is therefore highly appreciated and can be...
by Jan Willem Bech | Vademecum
Jan Willem during a descent with Inspiration rebreather Rebreather types explained To explain all types of rebreathers in one page is an almost impossible task. Many systems are technically different and have their own specific characteristics. A rebreather is a...
by Jan Willem Bech | Vademecum
Henry’s law is a chemical law, named after the English scientist William Henry (1774-1836), which applies to the equilibrium situation of a solvent in contact with a gas. If there is contact between a gas and a liquid solvent, gas molecules will dissolve in the...
by Jan Willem Bech | Database Oxygen Rebreathers, Database OX GER
The long-actuated 1924 Bergbaugerät succeeded the 1923 model. The breathing apparatus has similarities with the 1924 HSS gerat, which was developed for military purposes and was carried lower on the back. The casing is also different. The housing of the Modell 1924...
by Jan Willem Bech | Homebuilders
The Draeger apparatus model HSS 1924 is a so-called ‘seitenschlauchmodell’ a breathing apparatus where the breathing hoses run under the arm to the breathing apparatus. It was developed for the army and is therefore called ‘Heeres...
by Jan Willem Bech | Database Oxygen Rebreathers, Database OX GER
The back-mounted fire and rescue unit was developed by Dräger in 1924. It was used to fight fires for civilian purposes and in the mining industry. Further information on this device is required in addition to this datasheet. Courtesy: Deutsches Bergbau-Museum Bochum,...
by Jan Willem Bech | Database Oxygen Rebreathers, Database OX GER
Dräger Sauerstoff Klein Gasschützgerät Modell KG210 KG stands for ‘Klein Gasschutzgerät’ and was developed between WW1 and WW2. The model KG2100 was the successor to model KG1928 and was produced in large numbers. It was designed for civil defence and fire...
by Jan Willem Bech | Database Oxygen Rebreathers, Database OX GER
Dräger Sauerstoff Klein Gasschützgerät Modell KG130 KG stands for ‘Klein Gasschutzgerät’ and was developed between WW1 and WW2. The model KG130 was the successor to model KG1928 and was produced in large numbers. It was designed for civil defence and fire...
