The main measuring components of a glass rotor flowmeter are a vertically installed lower small and upper large conical glass tube and a float that can move up and down inside. When the fluid passes through the conical glass tube from bottom to top, a pressure difference is generated between the upper and lower parts of the float, and the float rises under this pressure difference. When the upward force, buoyancy, and viscous lift acting on the float are equal to its gravity, the float is in an equilibrium position. Therefore, there is a certain proportional relationship between the fluid flow rate flowing through the glass rotor flowmeter and the rising height of the float, that is, the flow area of the glass rotor flowmeter. The position height of the float can be used as a measure of flow rate.
The glass rotor flowmeter is often used in the aeration pipeline, and this phenomenon can be seen frequently! Next, we will analyze the reasons and solutions for you.
The reason is that the pressure in your pipeline is too low, and the gas pressure cannot reach the level required to lift the float of the metal rotor. The specific process is as follows:
Process decomposition one: Low pipeline pressure prevents the float from rising, resulting in the actual flow meter not being opened and the pipeline being closed
Process decomposition 2: The flowmeter float is not open, but the fan is working, causing an increase in pressure in the pipeline
Process decomposition three: When the pressure inside the pipeline increases beyond the weight of the metal float, the float is suddenly pushed up, causing the pipeline to open
Process decomposition four: Due to the opening of the pipeline, gas is quickly released, resulting in a decrease in gas pressure at the front end of the flowmeter, which cannot balance buoyancy and the weight of the float. The float falls down again, and the pipeline is closed again.
In such a cycle, the metal float keeps bouncing and cannot accurately measure.
The solution is as follows:
Install a valve downstream of the glass rotor flowmeter to increase the working pressure of the entire pipeline. If your fan pressure can be increased significantly, then this can solve the problem.
If the working pressure of the fan is not sufficient, it is recommended that you replace the flow meter. You can use a vortex flowmeter or a turbine flowmeter to solve the measurement problem.