Manual nitrox mixing chamber-Nitrox stick.
Nitrox is an artificial breathing mixture of air and oxygen used in diving.
- The continuous mix method is used to prepare nitrox mixtures, among other methods. This method allows for the production of nitrox mixtures up to 40% O2 using a standard compressor. This method involves adding pure oxygen to the air drawn in by the compressor. The added oxygen and air are mixed before entering the compressor in a mixing chamber, also known as a nitrox stick, to achieve a homogeneous mixture. At the exit of the mixing chamber, the mixed gas is continuously analyzed by an oxygen analyzer connected to the system. The analyzer’s readings are the basis for manual regulation of the oxygen flow into the mixing chamber. Manual regulation is performed using a knob on the oxygen regulator connected to the oxygen cylinder.
Manual adjustment requires the constant presence of a person mixing the gas, i.e., the gas blender. Oxygen flow setting may require periodic adjustments during compressor operation due to a decrease in compressor efficiency as discharge pressure increases. Fluctuations in analyzer readings of up to +/- 0.5% can be ignored. Above this value, the oxygen flow should be corrected.
The entire mixing system includes the following components:
- Oxygen regulator
- Oxygen hose connecting the regulator to the mixing chamber
- Oxygen analyzer with external oxygen sensor
- Mixing chamber
- The complete set, of course, requires a replaceable oxygen cylinder, preferably with a capacity of 10-50 liters and an operating pressure of up to 200 bar, and a compressor. Compressors have varying capacities. The most popular ones used in diving clubs and centers range from 100-300 liters/min, or 6-18 m³/h. Such a wide range of capacities also requires oxygen regulators with oxygen flow rates of up to 75 liters/min, or 4.5 m³/h. Such high flow rates can only be achieved by oxygen regulators used in gas welding. A medical oxygen regulator has a maximum flow rate of 25 liters/min, making it suitable only for small compressors with capacities no greater than 110 liters/min. These limitations make it much more advantageous to use oxygen welding regulators, which unfortunately lack a precise oxygen flow regulation scale.
- This flow is manually regulated while continuously monitoring the oxygen analyzer’s readings. It’s also important that the oxygen analyzer be equipped with an oxygen sensor whose response time to the presence of oxygen is no longer than 5 seconds. Once established, the flow can, of course, change slightly as the cylinder is filled with gas, so a blender must be present at all times during this filling method. Another important issue is the construction of the mixing chamber itself. It should be small enough to allow the system to react quickly to flow changes and should not have too many constricting or blocking elements, which could increase suction resistance during this mixing phase. There are several methods for achieving a homogeneous mixture, including mixing by swirling the oxygen and air streams, mixing by separating the oxygen stream within the stream drawn in by an air compressor, or mixing using special baffles or plastic balls with holes. One of these methods is used in my mixer. The mixing chamber is constructed of interconnected PVC pipes. This makes it lightweight and easy to hang on the wall, and after disassembly, it can be easily cleaned inside. It also has a replaceable tip for connecting to the compressor’s suction hose.
- The table below lists the price of mixing systems in various versions. The price also includes installation assistance and operating instructions.
| Typ | Zdjęcie | Opis | Cena | Zamówienie |
|---|---|---|---|---|
| Kompletny system do mieszania ciągłego |  | W skład kompletnego systemu wchodzi: komora mieszająca, analizator tlenu, reduktor tlenowy i przewód tlenowy | 1400 zł | Zamów |
| Komora mieszająca z reduktorem tlenowym |  | Komora mieszająca z reduktorem i przewodem tlenowym | 700 zł | Zamów |
| Komora mieszająca | | Komora mieszająca krzyżowym systemem mieszania strumieni gazu, wejściem dla przewodu tlenowego i wejściem na sensor tlenu | 550 zł | Zamów |