Answer / rambalaji

1. zirconia oxygen analyzers determine oxygen concentration using the conductivity of a zirconia ceramic cell. Zirconia ceramic cells only allow oxygen ions to pass through at high temperatures (750oC). With reference gas on one side and sample gas on the other, oxygen ions move from the side with the highest concentration of oxygen to that with the lowest concentration. The movement of ions generates an EMF (Electro Motive Force) which can be measured to determine the oxygen content

2. The sensor does not actually measure oxygen concentration, but rather the difference between the amount of oxygen in the flue gas and the amount of oxygen in the air. Rich mixture causes an oxygen demand. this demand Causes high voltage to build up due to transportation of oxygen ions through the sensor layer. Lean mixture causes low voltage since there is oxygen Excess. Sensor working in Nernst Principle
In flue gas side O2 is low : High Voltage

In flue gas side O2 is high : Low Voltage

High Concentration : O2 + 4 e  2O2 -

Low Concentration : 2O2 -  O2 + 4 e

0% O2 = 0.82 mv

5% O2 = 0.40 mv

21% O2 = 0 mv

Answer / manikandana

. When temperature increases the content of oxygen decreases.- principle.
Reference gas(span gas) instrument air 21% O2.
1% gas should provide from cylinder for cal purpose.

So I'm a first year apprentice and I'm having a tough time with knowing the difference between AI, AO, DI, DO. I'm having a hard time understanding what devices are which and why. Can someone explain this to me?

2 Answers  

---

How will you calibrate PID controller? explain with example.

0 Answers   Jacobs, Sirte Oil Company,

---

Q- In the process of checking AC through Phase Tester our body is the part of circuit but we don't recevie Shock, Why ?

2 Answers  

---

pls suggest suitable MOC of diaphragm for pressure measurement of UREA grade solution service fluid.

0 Answers   Siemens,

---

can anyone guide me how to get any of the previous year GAIL question papers? are they available? 0n 2nd august i have to take the written test.

0 Answers  

---

---

What is surge in compressors? How to detect and control it?

1 Answers   DEWA,

---

which transister (npn or pnp) is used in vibration monitoring for negative voltage? 

2 Answers  

---

why temperature transmitter is showing ambienttemp.but 21.5ma. alarm AO showing at the display &how to sloves this problem.

2 Answers  

---

What is the working principal of Mass flow transmitter?

1 Answers  

---

how to rectify the poor signal strength in utrasonic digtial flow meter ,model:ge digital xce868i

0 Answers   KNPC,

---

which are types of orifice tap ?

2 Answers  

---

if we have 380 KVA DG. how to calculate Power Factor. With detailed formula

1 Answers  

---