Calculate Differential Pressure Sensed by Level Transmitter

Calculate Differential Pressure Sensed by Level Transmitter

Question :

Calculate the differential pressure sensed by the level transmitter at three different water levels in this boiler steam-drum level measurement system: The measurable points are 0%, 50%, and 100% of transmitter range.

Assume a density for (hot) boiler drum water of 36 lb/ft³ , a density for steam in the drum of 7 lb/ft³ , and a density for (warm) water in the “wet leg” of 61.8 lb/ft3 . If the pressure at the “low” (L) side of the transmitter is greater than the pressure at the “high” (H) side, be sure to express the differential pressure quantity as a negative number.

Credit will be given for correctly calculating each of the differential pressures:

• (6 points) Transmitter ∆P at 0% water level     = _______”W.C.
• (6 points) Transmitter ∆P at 50% water level   = _______”W.C.
• (6 points) Transmitter ∆P at 100% water level = _______”W.C.

Answer :

1. (6 points) Transmitter ∆P at 0% water level = -38.832 ”W.C.
2. (6 points) Transmitter ∆P at 50% water level = -31.864 ”W.C.
3. (6 points) Transmitter ∆P at 100% water level = -24.896 ”W.C.

Also Read : Boiler Drum Level Measurement Principle