When selecting the type of radar level gauge, consider the influence of stirring and vacuuming, and pay attention to the power supply and output signal.
1. Selection under stirring
In a tank with stirring, guided wave radar is generally not used. The force of stirring can easily bring the cable of the guided wave radar into the propeller, or bend the rod of the guided wave radar. Therefore, only high-frequency or low-frequency horn radar for non-contact measurement can be selected.
If the lowest liquid level on site is above the stirring propeller, it generally has no effect on the measurement. If the minimum liquid level will be lower than the stirring propeller, it is necessary to filter out the signal reflected by the propeller by learning the function of false echo, so as to ensure that the propeller is not used as a target when measuring.
2. Selection under vacuum conditions
Under vacuum conditions, the boiling point of liquids will be much lower than under standard atmospheric pressure. Many liquids start to boil at 30-40°C. Especially in the reaction kettle and evaporation kettle, when there is no vacuum, the liquid is very calm. When the vacuum is pumped, the liquid of 1 meter will become 3 meters high, all of which are boiling bubbles and fine water droplets. In this case, you can only use the bellmouth radar, and then make certain changes on site
Three, power supply and output signal
The radar's power supply is basically 24VDC on the market. If the customer requires 220VAC, then a 220VAC to 24VDC switching power supply is enough for him.
There are two types of radar output signals: 4-20ma and 485. 4-20ma is currently the dominant one and is widely used in industrial situations. There are few 485 users, and they are generally used in occasions that require low power consumption, such as water conservancy and hydrology, flash flood warning, etc.