Vortex flowmeters to avoid cavitation:

(1) Decrease the flow rate U When selecting the meter, the flow rate corresponding to the maximum flow rate should be calculated so that no cavitation occurs at this flow rate state; on the other hand, the minimum flow rate corresponding to the minimum flow rate is calculated. Do not lower than 0.4m/s to ensure the measurement accuracy of the vortex flowmeter under low flow conditions.

(2) The regulating valve should be installed farther downstream of the vortex flowmeter. Because there is a large pressure difference between the ammonia separator and the ammonia intermediate tank, most of the pressure difference falls on the regulating valve. When the liquid ammonia flows through the valve, the pressure drops suddenly, and a certain vaporization occurs. Phase flow. To prevent the two-phase flow from flowing through the vortex flowmeter, the regulator valve must be installed downstream of the vortex flowmeter. In addition, in order to avoid the frequent action of the regulating valve on the vortex flowmeter, the regulating valve should be as far away as possible from the vortex flowmeter.

(3) Decreasing the saturated vapor pressure P0 of liquid ammonia For a certain liquid, its saturated vapor pressure P0 is a function of temperature. The lower the temperature, the lower the P0. If you try to lower the temperature of the liquid ammonia before entering the flow meter, the saturated vapor pressure P0 can be lowered. The upstream pipe of the vortex flowmeter is changed into a jacketed pipe, and a small amount of liquid ammonia is introduced into the jacket. This part of the liquid ammonia is expanded by throttling, and after vaporization, the heat of the liquid ammonia in the pipe is taken away, thereby the liquid ammonia in the pipe. Provides a cooling capacity to reduce the temperature of the liquid ammonia flowing through the vortex flowmeter. The ammonia can be returned to the recovery system after vaporization.

(4) If there is a shut-off valve upstream of the vortex flowmeter, the shut-off valve should be fully open during operation, and cannot be opened or opened partially. At the scene, when the shut-off valve was gradually closed, the indication value of the vortex flowmeter not only decreased but also increased. The reason is that when the valve is closed, the liquid ammonia is decompressed by the valve, the potential energy changes the kinetic energy and the heat energy, and the liquid ammonia is vaporized, causing the volume to suddenly expand, the flow rate increases, the instrument output increases sharply, and a false signal is generated. This article is from http://
Http://
Http://
Http://
Please keep this link when reprinting http://!