Fixed-gear flowmeter for medical oxygen generator
Fixed-gear flowmeter for medical oxygen generator
Introduction: Reasons for the influence of flow on oxygen concentration
Under normal working conditions, the oxygen concentration of the oxygen generator is stable when outputting oxygen at the rated flow rate. When outputting oxygen exceeding the rated flow rate, the oxygen concentration decreases. The reason is easy to understand as it exceeds the oxygen production capacity. However, there is another phenomenon that when the oxygen generator operates at a very low flow rate below the rated flow rate, the oxygen concentration will also decrease. This is difficult to explain by oxygen production capacity. At present, there is no scientific explanation and conclusion for the phenomenon of reduced oxygen concentration when operating at low flow rates. Personally, it is understood that low flow output leads to an increase in the gas remaining in the molecular sieve container within the rated period. The excess gas saturates the adsorption capacity of the molecular sieve, and part of the nitrogen overflows, resulting in a decrease in oxygen concentration. Therefore, in order to ensure that the oxygen concentration is not troubled by changes in flow rate, the upper flow limit restriction and lower flow compensation of this product will solve this problem.
1. Structure introduction
2. Inlet air, high pressure area
When the airflow pipeline is connected to the air inlet interface, the position of the red line is the high-pressure area.
3. Adjust the knob to the required gear
By rotating the knob to drive the valve stem and flow plate to rotate. The valve stem is provided with a wavy groove and interacts with the spring positioning mechanism to ensure the hand feeling of each rotation. When the gear is in place, there will be a slight collision sound and hand feeling to determine the gear connection. After being connected, the gas path controls the flow through the micropores of the flow plate. The flow will fluctuate according to the set input pressure. When the set pressure is 45-55 kpa, the output range of the flowmeter is 0.5 to 5 liters, with each 0.5 as a gear.
4. Pressure relief at low flow rate
Oxygen concentrators have the phenomenon of oxygen concentration drop when working for a long time at low flow rate. The lowest value of this phenomenon is generally 2 liters per minute. That is, during the working process of the oxygen concentrator, when the flow rate is not lower than 2 liters per minute, the oxygen concentration will not drop. Therefore, we need to add pressure relief when the flow rate is below 2 liters. Add 2 liters of pressure relief when the gear is at 0.5 liters per minute, add 1.5 liters of pressure relief when the gear is at 1 liter per minute, and add 1 liter of pressure relief when the gear is at 1.5 liters per minute.
5. Flow-limiting disc
Core component flow-limiting disc: Through thousands of tests and explorations to obtain effective data, combined with a high-precision injection molding solution and a strict screening process, it is ensured that the flow deviation of each gear is within ±5% or ±100 ml (take the smaller value between them). Ensure the smooth passage of the oxygen generator's flow accuracy test.
