1. HELIUM LEAK TEST OF INNER BORE WELDS OF TUBE#TUBESHEET JOINT
Title:
HELIUM LEAK TEST OF INNER BORE WELDS OF TUBE#TUBESHEET JOINT BY PRESSURISING THE TUBE(38.1MM OD) FROM INSIDE WITH SPECIAL FIXTURING ARRANGEMENT
Company Name:
Larsen & Toubro Limited,
Heavy Engineering Division,
Hazira Manufacturing Complex,
Dist:Surat
Tel:
Fax:
Authors:
S P Ghiya
J L Songhela
N S Choksi
Date: 10th October, 2010
Location: Dubai

2. Products Reactor Column Regenerator Steam Generator EO Reactor
Automation in PT evaluation of internal weld for Small Bore (4” to 12”), having longer pipe (up to 2000 mm.)
Products
Reactor
Column
Regenerator
Steam Generator
EO Reactor
End Shield
PP Reactor
Reactor
Product Splitter

3. Automation in PT evaluation of internal weld for Small Bore (4” to 12”), having longer pipe (up to 2000 mm.)
HELIUM LEAK TEST OF INNER BORE WELDS OF TUBE#TUBESHEET JOINT
Introduction
Leaks are special types of defects which can have a major importance in systems where they have influence on safety and performance.
Many objects will have a reduced reliability if they contain leaks
Leak testing is a non destructive examination method which is used for detection and localisation of leaks and for measurement of leakage in systems

4. HELIUM LEAK TEST OF INNER BORE WELDS OF TUBE#TUBESHEET JOINT
Automation in PT evaluation of internal weld for Small Bore (4” to 12”), having longer pipe (up to 2000 mm.)
HELIUM LEAK TEST OF INNER BORE WELDS OF TUBE#TUBESHEET JOINT
In principle two methods are applied for leak testing and localisation of leaks, the "Vacuum method" and the "Overpressure method".
At the "Vacuum method" the object to be examined for leaks is evacuated and sprayed from the outside with a search gas, in this case Helium. The gas enters through any leaks present in the object and is detected by a sensor connected to the leak test instrument
At the "Overpressure method" the object to be examined for leaks is filled with a search gas, Helium, under slight overpressure. The search gas escapes through any leaks present to the outside and is detected by a detector probe. This detector probe is in most cases called a "sniffer" acting as a gas sampling probe.

5. HELIUM LEAK TEST OF INNER BORE WELDS OF TUBE#TUBESHEET JOINT
Automation in PT evaluation of internal weld for Small Bore (4” to 12”), having longer pipe (up to 2000 mm.)
HELIUM LEAK TEST OF INNER BORE WELDS OF TUBE#TUBESHEET JOINT
Leak rates down to mbar l / s can be detected
Both objects with vacuum or overpressure can be examined
the objects can be examined during operation
The examination can be performed fast and effective
Non poisonous, non explosive and inexpensive gasses are applied
Leaks can be detected in due time to prevent safety or operational hazards
Leaks can be detected in due time to prevent unplanned and expensive shut downs

6. HELIUM LEAK TEST OF INNER BORE WELDS OF TUBE#TUBESHEET JOINT
Automation in PT evaluation of internal weld for Small Bore (4” to 12”), having longer pipe (up to 2000 mm.)
HELIUM LEAK TEST OF INNER BORE WELDS OF TUBE#TUBESHEET JOINT
IBW is mainly done to prevent accumulation of process fluid between the gap of outer surface of tube and tube sheet hole.

7. Vacuum method - Hood test Vacuum method - Tracer probe test
HELIUM LEAK TEST OF INNER BORE WELDS OF TUBE#TUBESHEET JOINT
Vacuum method - Hood test
Vacuum method - Tracer probe test
Overpressure method - Hood test
Overpressure method - Bombing test
Overpressure method - Sniffer test
Helium Leak Test, Vacuum Method, Hood Test

8. Vacuum method - Hood test Vacuum method - Tracer probe test
HELIUM LEAK TEST OF INNER BORE WELDS OF TUBE#TUBESHEET JOINT
Vacuum method - Hood test
Vacuum method - Tracer probe test
Overpressure method - Hood test
Overpressure method - Bombing test
Overpressure method - Sniffer test
Helium Leak Test, Vacuum Method, Tracer probe test

9. Vacuum method - Hood test Vacuum method - Tracer probe test
HELIUM LEAK TEST OF INNER BORE WELDS OF TUBE#TUBESHEET JOINT
Vacuum method - Hood test
Vacuum method - Tracer probe test
Overpressure method - Hood test
Overpressure method - Bombing test
Overpressure method - Sniffer test
Helium Leak Test, Overpressure Method, Hood test.

10. Vacuum method - Hood test Vacuum method - Tracer probe test
HELIUM LEAK TEST OF INNER BORE WELDS OF TUBE#TUBESHEET JOINT
Vacuum method - Hood test
Vacuum method - Tracer probe test
Overpressure method - Hood test
Overpressure method - Bombing test
Overpressure method - Sniffer test
Helium Leak Test, Overpressure Method, Bombing test.

11. Vacuum method - Hood test Vacuum method - Tracer probe test
HELIUM LEAK TEST OF INNER BORE WELDS OF TUBE#TUBESHEET JOINT
Vacuum method - Hood test
Vacuum method - Tracer probe test
Overpressure method - Hood test
Overpressure method - Bombing test
Overpressure method - Sniffer test
Helium Leak Test, Overpressure Method, Sniffer test.

12. HELIUM LEAK TEST OF INNER BORE WELDS OF TUBE#TUBESHEET JOINT
Automation in PT evaluation of internal weld for Small Bore (4” to 12”), having longer pipe (up to 2000 mm.)
HELIUM LEAK TEST OF INNER BORE WELDS OF TUBE#TUBESHEET JOINT
Heat Exchanger — Vertical View

13. HELIUM LEAK TEST OF INNER BORE WELDS OF TUBE#TUBESHEET JOINT
Inner bore weld leak tested using Helium lwith following parameters.
Tube Sheet details: hole dia * 180mm thick * 5576mm dia
Tube Sheet material:: SA 182M-304H
Tube Details: 38.1mm OD * 2.11 thick * 5820mm long*
No of tubes: tubes
Material: SA213 M-304H individually.

14. HELIUM LEAK TEST OF INNER BORE WELDS OF TUBE#TUBESHEET JOINT
180mm
Tube sheet
Tube

15. HELIUM LEAK TEST OF INNER BORE WELDS OF TUBE#TUBESHEET JOINT
Tube # Tube sheet welding using inner bore welding scheme

16. HELIUM LEAK TEST OF INNER BORE WELDS OF TUBE#TUBESHEET JOINT
Cross section of tubes, welded with tube sheet

17. HELIUM LEAK TEST OF INNER BORE WELDS OF TUBE#TUBESHEET JOINT
Heat Exchanger fabrication under progress-Vertical assembly

18. HELIUM LEAK TEST OF INNER BORE WELDS OF TUBE#TUBESHEET JOINT
Verification of Probe size and its functioning on mock up

19. HELIUM LEAK TEST OF INNER BORE WELDS OF TUBE#TUBESHEET JOINT
Helium Leak Testing Equipment

20. HELIUM LEAK TEST OF INNER BORE WELDS OF TUBE#TUBESHEET JOINT
Tube fit up/ welding /visual/ ferrite testing in progress in vertical condition

21. HELIUM LEAK TEST OF INNER BORE WELDS OF TUBE#TUBESHEET JOINT
Tube fit up checking in progress in horizontal condition

22. HELIUM LEAK TEST OF INNER BORE WELDS OF TUBE#TUBESHEET JOINT
Tube sheet View from Bottom Side

23. HELIUM LEAK TEST OF INNER BORE WELDS OF TUBE#TUBESHEET JOINT
Top view from tube open end…..mock up work for tube # tube sheet welding

24. HELIUM LEAK TEST OF INNER BORE WELDS OF TUBE#TUBESHEET JOINT
Tube # Tube Sheet joint Inspection Testing Requirements
Fit up-Inspection
Weld Visual Inspection (Inside & Outside)
PT of completed weld (Inside & Outside)
Ferrite Check ( From outside only )
Helium Leak test (After each tube welding)
Pneumatic Test
Hydrotest

25. HELIUM LEAK TEST OF INNER BORE WELDS OF TUBE#TUBESHEET JOINT
Helium Leak Testing Sequence
Isolate joint from inside by providing leak proof fixture as shown in fig.
Pressurize helium with 5 Psi ( 0.35 Kg / Sq. Cm) to 10 Psi ( Kg/ Sq.Cm)
Hold the pressure for minimum 30 Seconds
Check the leakage from the other side with snifter probe of Helium test
equipment
Repeat the exercise for the complete row
In case leak is noticed, repair the weld , before proceeding to the next raw
Preparedness:
Total twenty such fixtures were made and connected them through a
manifold
This arrangement enabled us to perform this test at a time in multiple
joints in a row

26. Automation in PT evaluation of internal weld for Small Bore (4” to 12”), having longer pipe (up to 2000 mm.)
HELIUM LEAK TEST OF INNER BORE WELDS OF TUBE#TUBESHEET JOINT
Helium Leak Test Probe
Outlet connecting to MSLD
Tube
Tube Sheet Face

27. Helium leak test probe
HELIUM LEAK TEST OF INNER BORE WELDS OF TUBE#TUBESHEET JOINT
3-D Model of Helium Leak Test Probe
Hole
Probe
Handle for tightening
O-Rings
Handle for holding

28. HELIUM LEAK TEST OF INNER BORE WELDS OF TUBE#TUBESHEET JOINT
Probe
Probe with Helium “standard leak”

29. HELIUM LEAK TEST OF INNER BORE WELDS OF TUBE#TUBESHEET JOINT
Weld Visual Testing in Progress

30. HELIUM LEAK TEST OF INNER BORE WELDS OF TUBE#TUBESHEET JOINT
Weld Bead Finish Through Video Scope , Displayed on Computer Terminal

31. HELIUM LEAK TEST OF INNER BORE WELDS OF TUBE#TUBESHEET JOINT
Conclusion :
This technique of inspecting flaws in Inner Bore Weld of small diameter and inaccessible from outside has provided immense confidence to all NDT personnel involved including customer, ensuring defect free weld quality.

32. Thank You