Answer / carl_ellis

A closed pressure vessel requires a differential pressure
measurement in order to compensate for the pressure or
vacuum in the vapor space above the liquid.

The density is said to be 1, so we'll assume that what was
really meant is that the specific gravity is 1.00, the same
as the specific gravity of water. The measurement can be
made in engineering units of mm of water column (wc) with no
compensation for a specific gravity other than water.

A DP transmitter measurement:
(high side pressure) minus (low side pressure)

The low side pressure reading is (vacuum pressure).
The high side pressure reading is (column of water pressure
+ vacuum pressure)

(water column pressure + vacuum pressure) minus vacuum
pressure = water column pressure.

With a vertical elevation difference between the flanges of
440mm, the water column pressure will be
0 - 440mm wc.
LRV = 0.0 mm wc
URV = 440 mm wc

Carl Ellis
Measure First

HOW TO CONVERT 0-60KG/CM2 PRESSURE TRANSMITTER TO A LEVEL TRANSMITTER? CAN WE ABLE TO DO IT? IF YES HOW TO DO IT BY USING HART?

3 Answers  

---

What is difference between magnetic flow transmitter & Electromagnetic flow transmitter?

1 Answers  

---

In control valves (like feed water control valve) we will give 3 kg pressure and how it controls 110 kg of water pressure?

4 Answers   SSL,

---

what is the electrical operation procedure for switching on 27.6MVA electric furnace.

0 Answers   Jindal,

---

What is sensitivity in vibration probes..?

0 Answers   Lanco,

---

---

in sports(eg,cricket) what is the technique for measurement of speed of the ball thrown by the bowler.

6 Answers   BEL, PSU,

---

EXPLAIN SOME IMP QUESTIONS AND ANSWERS ON TOPIC ELECTRONICS,INSTRUMENTATION.........

1 Answers   ONGC,

---

A temperature sensor (RTD) connected via a temperature transmitter is adjusted to give an output of 4ma at 60 deg and 20 ma at 600 deg. This output (4-20ma) from the transmitter is connected to an IGBT-inverter to control a high speed (-12,000 to +12,000 RPM) DC motor. And in the inverter it is programmed as, for 4ma the motor speed will be -3,000 RPM and for 20ma the motor speed will be +10,000 RPM. The question is : If the motor speed is +5,500 (RPM), what will be the temperature? (-sign indicates that the motion is in reverse direction).

9 Answers  

---

How many ohms are required for proper earthing?

0 Answers  

---

Someone please do mail me some instrumentation questions for Hindustan Petroleum test to avinalexander@gmail.com .Really would be gateful if someone could help me

3 Answers   HPCL, Immersion, IOCL,

---

What is the purpose of the analyzer in petrochemical plant?

0 Answers   ENI, Lakshmi Machine Works,

---

Which products are available in the Mass Systemswitch and System Manager AC range?

0 Answers  

---