Why can’t double-flange level gauges be used for measuring the liquid level in boiler drum? What are the specific reasons?
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Having visited so many factories, aside from one medium-pressure boiler that uses a double-flange level gauge, the rest all use balance vessels and similar devices. Why is the double-flange method inaccurate for measuring liquid levels?
It’s related to the conditions inside the boiler, right? It will affect the actual measurements. Double flanges are not suitable
My understanding is that the temperature of the boiler water is high and varies significantly, so a balancing vessel is needed for compensation.....
1. The pressure inside the steam drum is generally above 10 MPa. 2. There are both gas and liquid phases inside the steam drum, with temperatures above 400 degrees
The operating temperature of the diaphragm box is around 300 degrees, which is close to the temperature of medium-pressure steam; therefore, it is not widely used. For use with medium-pressure steam, it’s better to have longer pipes, as the diaphragm box can help reduce the temperature. There are many applications for low-pressure steam, with the aim of eliminating the need for heat tracing in the pressure transfer pipes; however, attention must also be paid to the minimum ambient temperature of the filling oil.
It sounds like it makes sense. A few days ago someone asked me about this; after thinking about it, I figured that theoretically it’s fine – it seems that in practice the double flanges don’t meet the requirements
The density of water changes significantly with temperature and pressure. Double flange measurements are based on the assumption that the density of water is constant; if the density is not constant, the measurements will be inaccurate
Double flanges definitely won’t work; I think I used a float before, and it seemed like that would end in disaster as well
This post was last edited by lotos1987 on 2016-2-28 at 22:29. Imbalances between water supply and evaporation introduce fluctuations; during these fluctuations, phase changes occur, resulting in an incorrect liquid level reading. Furthermore, during the phase change process, the pressure above the liquid level changes. Introducing a balance vessel is to avoid the pressure changes that occur during phase changes, by converting the pressure difference between steam and water into a difference in water level.