What is the issue regarding how to set the range when using a pressure transmitter to measure the liquid level in an open container?
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Two pressure transmitters are used to measure the liquid levels in two open tanks, A and B. The medium contained in these tanks is water; the bottom diameter of tank A is 13 m, while that of tank B is 16 m. Both tanks have a height of 17 m. The pressure transmitters are installed at a height of 1 m above the bottom of each tank. What is the range of each pressure transmitter in tanks A and B? If the water level in both tanks is maintained at 15 m, are the pressures exerted on the two pressure transducers the same at this time? (What is the value in kPa for each?) ）
The pressure generated by a liquid column: P=ρgh. According to this formula, the magnitude of the pressure depends only on the height of the liquid column, the density of the liquid, and the local acceleration due to gravity; it is independent of the diameter of the bottom surface of the tank. The range of the pressure transmitter can be calculated using this formula.
10 meters of water corresponds to one atmosphere of pressure, and one atmosphere equals 100 kilopascals; therefore, both containers have a pressure of 150 kilopascals
Measuring liquid level depends only on the height of the liquid level and the density of the medium; it is unrelated to area or shape. The static pressure acting on the pressure transmitter is calculated using the formula P=ρgh. The range of measurement is determined based on the actual maximum liquid level in the tank, and the highest value can be chosen. (1 meter ≈ 10 kPa; the pressure transmitter is located 1 meter above the bottom of the tank.) Therefore, the range can be 17 – 1 = 16 kPa. If the water level in both tanks is maintained at 15 m, are the pressures exerted on the two pressure transducers the same at this time? (What is the value in kPa for each?) ) The same, approximately (15-1) = 14 kPa.
Among the upper floors, only the second floor mentioned the need to take the value of gravitational acceleration into account in the calculations; the others assumed a value of 10 for gravitational acceleration, which results in an error of about 2% in the calculated values. Let’s still calculate it based on the 2nd floor.