Calculation of the liquid level in fire tanks
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I have two fire tanks here, each 8 meters high. A single-flange level transmitter is installed at the bottom of the tanks; I need an alarm when the liquid level reaches 7.2 meters and another alarm when it reaches 7.35 meters. Therefore, I set the range of the level transmitter to 72KPa–73.5KPa. I would appreciate comments from those with more experience on this. The transmitter is a single-flange differential pressure level transmitter. The low-pressure side is connected to the atmosphere.
The top of the fire tank must have an opening to the atmosphere! H = P/density * g; more precisely, g can be taken as 9.8, or 10 is also fine – there’s nothing much to discuss about it
Fire tanks have an opening to the atmosphere.
:If it’s a handshake, then there’s no problem
Is the underreported value still 7.2 meters? The reported height is only 7.35 meters, with a liquid level control range of 0.15 meters? Setting it up – I’m drunk too.
The liquid level elevation is a requirement of the owner.
I’ve never seen it done this way; what does calling the police have to do with the measurement range? Alarm detection is not the responsibility of the control system; will the measurements still be accurate if you change the range?
The range should be set according to the measurement range, not based on the alarm range, right?
The range should be set according to the measurement range, not based on the alarm range, right?
Regarding the relocation and range of single-flange level transmitters: 1. Scenarios where a single-flange level transmitter does not require relocation. Single-flange level transmitters can only be used for measuring the level in open containers. When the single-flange level transmitter PT and lower flange A are at the same height: ◆ Instrument range: △P=ρ×g×H0 ◆ At zero liquid level: actual liquid level H=0, and the pressure of the pressure transmitter P=0 ◆ At full liquid level: actual liquid level H=H0, and the pressure of the pressure transmitter P=ρ×g×H0; therefore, the range of the single-flange level transmitter is 0~ρ×g×H0. ◆ When the single-flange level transmitter PT and lower flange A are at the same height, there is no need to adjust the range of a single-flange level transmitter with a specified range of △P=ρ×g×H0. Single-flange level transmitter yunrun.com.cn/product/809.html 2. Applications for positive migration of single-flange level transmitters: Single-flange level transmitters can only be used for measuring the level in open containers. When the variable liquid level is above the installation height of the single-flange level transmitter PT: ◆ The range specified when ordering the instrument is △P=0~ρ×g×H0. ◆ At the zero liquid level, the actual liquid level H0=0, and the pressure of the single-flange level transmitter is P=ρ×g×H1. ◆ At the full liquid level, the actual liquid level is H=H0+H1, and the pressure of the transmitter is P=ρ×g×H0+ρ×g×H1; thus, after positive migration, the range of the single-flange level transmitter becomes from ρ×g×H1 to ρ×g×H0+ρ×g×H1. ◆ When the lowest variable liquid level is above the installation height of the single-flange level transmitter PT, the range specified when ordering is △P=0~ρ×g×H0, and the single-flange level transmitter needs to be positively migrated by an amount of ρ×g×H1. After positive migration, the 4-20mA output signal of the single-flange level transmitter corresponds to the height of the variable liquid level (ρ×g×H0), rather than the actual liquid level height in an open container. If the user needs to display the actual liquid level height in an open container, it is necessary to add a constant value of liquid level height (ρ×g×H1) to the liquid level display instrument or DCS; that is, the actual liquid level height = ρ×g×H0 + ρ×g×H1
Thank you for the reminder; I’ve corrected it and have learned a lot from it.