Level calculation for pressure transmitter with capillary

Level Pressure Q&A

I have a level transmitter with capillary, and I need to do the level calculation. The transmitter is one meter below the takeoff point, and the tank's takeoff point is five meters. The product's specific gravity is 0.89, and the capillary is filled with glycol at a specific gravity of 1.02. How can I calculate the level range?

Expert’s answer: Level calculation for pressure transmitter with capillary

So, you need to learn how to do level calculation for pressure transmitter with capillary? Okay, here’s what you need to know:

Level calculation never changes on a differential pressure transmitter; once you understand the equation, you can do any other range calculation. Now, there are several types of DP pressure installations to level measurement; I’ll give you a step by step based on your problem.

Level calculation for pressure transmitter with capillary
Example sent by the customer

Level at 0%

  • HP – LP
  • (Height H side x Capillary density) – (Height L side x Capillary)
  • (1000 x 1.02) – (6000 x 1.02)
  • 1020 – 6120
  • DP0% = – 5100 mmWC

Level at 100%

  • HP – LP
  • (Height H process side x Process density) + (Height H side x Capillary density) – (Height L side x Capillary)
  • [(5000 x 0.89) + (1000 x 1.02)] – (6000 x 1.02)
  • [4450 + 1020] – 6120
  • 5470 – 6120
  • DP100% = -650 mmWC

Instrumentation training courses:

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