QUESTION & ANSWER

(1) How do you identify an orifice plate in pipe line?

An orifice tab is welded on the orifice plate which extends out of the line giving an indication of the orifice plate.

(2) Why is the orifice tab provided?

The orifice tab is provided due to the following reason.

1.     Indication of an orifice plate in the line.

2.     The mark the inlet of an orifice plate.

3.     The tag number of an orifice plate.

4.     The material of an orifice plate.

5.     The orifice diameter is mark on it.

(3) How to identify the direction of an orifice plate?

The orifice should be mounted with it is sharp edge facing the direction of fluid (liquid).

(4) How do you identify the HP side or inlet of an orifice plate in line?

The mark is always done HP side (inlet) of the orifice tab while gives an indication of the HP side.

(5) What the seal liquid used for filling impulse line or crude and viscous liquid?

Glycol liquid.

(6) How do you carry out piping for a differential pressure flow transmitter on liquid, gas and steam service? Why?

Liquid service :- on liquid line transmitter is mounted below the orifice plate or pipe line, since liquid have a property of self draining.

Gas service :- on gas service transmitter is mounted above the orifice plate or pipe line, because gas have a property self venting and secondly condensate formation.

Steam service :- on steam service the transmitter is mounted below the orifice plate or pipe line with condensate pots. The pots should be at the same level.

(7) What are the primary measuring element for flow?

The primary elements used for measurement are

(1) ORIFICE PLATE                                        

      (2) VENTURI TUBE

(3) PITOT TUBE                                               

    (4) ANNUBARS

(5) TURBINE FLOW METER                          

   (6) FLOW NOZZLE

(7) ROTA METER                                          

       (8) MAGNETIC FLOW METER

(9) PD METER

(8) What is the relation between flow and DP (differential pressure) across an orifice plate?

Flow rate through and orifice plate is proportional to the differential pressure.

(9) What are the flow units?

Kg/hr, lts/min, gallon/min, t/hr, barrels/day, m³/hr, nm³/hr.

(10)  How would you do glycol filling or fill seal liquid in seal pots? Draw and explain?

The procedure for glycol filling or seal liquids is :

1.     Prepare the work permit.

2.     If the instrument is in control loop the control mode must be on manual (put the controller on manual).

3.     Closed the both primary isolation valves.

4.     Open the vent valve on the seal pots.

5.     Drain the used glycol if present by open the drain valve.

6.     Connect the hand pump on LP side while filling the HP side with glycol.

7.     Kept the equalizer valve open.

8.     Kept the LP side valve closed.

9.     Start pumping and fill glycol.

10.                        Same repeat for LP side by connecting pump to HP side keeping equalizer valve open and HP side isolation valve closed.

11.                        Closed the seal pots vent valve.

12.                        Check the transmitter zero and adjust if required.

13.                        Closed equalizer valve.

14.                        Open both the primary isolation valve.

(11)  Define work permit system?

The main objectives of the work permit system are:

·        To control all type of maintenance and work activities in a processing facility.

·        To defined the scope of work an mark necessary arrangement to carry out the work safety.

·        To communicate all responsible personnel related to the work/effected by the work.

·        To take all safety precautionary measures.

(12)  List various types of permit?

Permit used in company are cold work, hot work, confined space entry permit, excavation permit.

(13)  What are clearance certificates?

Clearance certificate are recommended (BlimN) by the senior operation supervisor to carry out necessary isolation and checks before the start of work. It is a written statement by a responsible person declaring the requested condition is met.

(14)  How to use a multimeter for resistance, volts and amperes?

Meter is selected to ohms, test probe (leads) are on common and ohms socket. Resistance is measured when there is a no power on any circuit.

            Voltage and EMF is measured by selecting the meter AC or DC volts. It is parallel measurement.

            Amperes (current) measurements done in series with a circuit, by using the common and milliamper (ma) sockets for the probes.

(15)  How many ohms equal to 1 kilo ohms and 1 mega ohms?

1000 ohms = 1 kilo ohms.

1000 kilo ohms = 1 mega ohms.

(16)  How does a float level switch operates?

The liquid level sensor being a float moves up due to an increase in level. A guide rod with a magnet at the end mechanically attached to the float also moves up a sealed tube. A micro switch with a paramagnet follower will operated the switch, which in turn change over the contact.