INTERVIEW QUESTIONS #4 - EQUIPMENT #3 HEAT EXCHANGER #2

Test your knowledge on heat exchangers. There are some questions from 'TEMA' also. 

Brush up your knowledge.

1. Why a sliding plate is provided on one side of foundation during the erection of heat exchanger? 

The sliding plate is provided to ensure the smooth movement during  thermal expansion of heat exchanger.

Foundation bolts should be loosened at one end of the unit to allow free expansion of shells. Slotted holes in supports are provided for this purpose.

2. What is function of impingement baffle? 

To prevent or minimize erosion of tube bundle components at the entrance and exit areas against impinging fluids. These are provided at the shell side inlet nozzle.

3. What is air-fin fan cooler used in process industries? 

Air fin cooler is a horizontal heat exchanger. The process fluid will be inside the tubes. The tubes are fixed with fins. By forced air, fins on the tubes  exchanges heat and thereby the process fluid inside the tube will get cooled. These are normally fabricated as per API 661.

4. What is meant by double tubesheet construction in heat exchanger? 

Double Tubesheet Construction is a type of construction in which two  spaced tubesheets or equivalent

are employed in lieu of the single tubesheet at one or both ends of the heat exchanger.

5. What is the difference between Expanded Tube Joint and Welded Tube Joint?

Expanded Tube Joint is the tube-to-tubesheet joint achieved by mechanical or explosive expansion of the

tube into the tube hole in the tubesheet. Welded Tube Joint is a tube-to-tubesheet joint where the tube is welded to the tubesheet.

6. A manufacturers name plate is written using paint in legible height in a TEMA exchanger. Comment your opinion. 

It is not acceptable as per TEMA standard. A manufacturer's nameplate of corrosion resistant material shall be permanently attached to the head end or the shell of each TEMA exchanger.

7. Why the manufacturers name plate is fixed on a projected surface in the shell or head end of a TEMA exchanger? 

As per TEMA standard, the manufacturers name plate shall be visible outside any insulation. So the name plate is fixed on a channel having projection (From the surface of heat exchanger) equal to more than the thickness of the insulation on the equipment.

8. What is meant by TEMA CLASS "R" Exchangers? 

The TEMA Mechanical Standards for Class "R" heat exchangers specify design and fabrication of unfired shell and tube heat exchangers for the generally severe requirements of petroleum and related processing applications.

9. What is meant by TEMA CLASS "C" Exchangers?

The TEMA Mechanical Standards for Class "C" heat exchangers specify design and fabrication of unfired shell and tube heat exchangers for the generally moderate requirements of commercial and general process applications.

10. What is meant by TEMA CLASS "B" Exchangers?

The TEMA Mechanical Standards for Class "B" heat exchangers specify design and fabrication of unfired shell and tube heat exchangers for chemical process service.

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