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

Draw a P& ID showing – orifice flange, plate, dp transmitter, isolation & bypass valves and tubing.

0 Answers   CCIE,

---

Explain, and give a real-world example of MODULATING control

1 Answers  

---

what is the path to communicate from profi to ofc.what is the means of communication.what is multi cire cable in ofc.

1 Answers  

---

difference between null and deflecting instrument.

5 Answers   ONGC,

---

What is trim material . Why it is known as trim.

1 Answers   L&T, LNG,

---

What are the problems faced while testing HART instruments?

1 Answers   SSC,

---

What is the difference bitween control net scaner and device net scaner

0 Answers   Binani,

---

what is the difference between Digital output DO signals /Commands for start/stop and Solenoid valves ??

1 Answers  

---

Paper Details: company -- Hindustan Copper Limited post -- GET 2008 Date -- 03.08.2008 Dept.-- Electronics?Instrumentation Aptitude -- 70 Technical-- 80 Total Time -- 2hr 30min I have listed the question I could able to remember 1. BCD equivalent of 43 2. value of K for stability of a system from a given equation 3. transformer connection for darlington connection 4. damping of balastic galvanometer 5. advantage of chart-pen recorder over CRo 6. CRO - how to change bandwidth 7. questions on CRO construction 8. reverse saturation current of si diode 9. advantage of wire wound resistance over carbon resistance 10. core material for a small coil 11. max fanout-- TTL/ECL/CMOS/MOS 12. component of resistance of monolithic IC 13. functions of capacitors in multivibrators 14. to change a sawtooth signal into a square wave we use-- schmit trigger/ schottkey diode/ zener diode 15. relation b/w á & â in transistor ckt 16. function of SiO2 layer in fabrication 17. 3 questions on ODD MAN OUT

2 Answers   HCL, L&T,

---

Explain the difference between differial pressure & delta pressure?

1 Answers  

---

It is desired to reduce effect of 50Hz pick up in a thermocouple measurement. If a third order LP filter is used for this, what should be its cut off frequency, if gain should be 0.001 at 50Hz.

1 Answers   Honeywell,

---

what is mapping in instrumentation and control engineering

2 Answers  

---