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UAE & Dubai Directory. We are listed under Middle East News and Media category . |
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Multi technique Tube Inspection Equipment :-
These days heat exchanger Tube inspection is easily execute with help of 4 techniques depends on clients requirements.
Specialized NDT Services provide multipurpose equipment which can be operate in 4 methods (Eddy Current, remote field Eddy
Current, MFL and IRIS).
Tube Inspection is often used to detect corrosion, erosion, cracking and
other changes in tubing. Heat exchangers and steam generators, which are used in power plants, have thousands of tubes that must
be prevented from leaking. This is especially important in nuclear power plants where reused, contaminated water must be prevented
from mixing with fresh water that will be returned to the environment. The contaminated water flows on one side of the tube
(inside or outside) and the fresh water flows on the other side. The heat is transferred from the contaminated water to the fresh
water and the fresh water is then returned back to is source, which is usually a lake or river. It is very important to keep
the two water sources from mixing, so power plants are periodically shutdown so the tubes and other equipment can be
inspected and repaired.
The Tube Inspection test method and the related remote field testing method provide high-speed inspection techniques for these
applications.Tube Inspection is often used to detect corrosion, erosion, cracking and other changes in tubing.
Heat exchangers and steam generators, which are used in power plants, have thousands of tubes that must be prevented from
leaking. This is especially important in nuclear power plants where reused, contaminated water must be prevented from mixing
with fresh water that will be returned to the environment. The contaminated water flows on one side of the tube (inside or outside)
and the fresh water flows on the other side. The heat is transferred from the contaminated water to the fresh water and
the fresh water is then returned back to is source, which is usually a lake or river. It is very important to keep the two
water sources from mixing, so power plants are periodically shutdown so the tubes and other equipment can be inspected and
repaired. The Tube Inspection test method and the related remote field testing method provide high-speed inspection
techniques for these applications.
Mainly 4 techniques to use for Tube Inspection Depends on material, thickness, Size of the tube and clients requirement.
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What is Eddy Current testing? |
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Eddy currents also called Foucault currents are currents induced in conductors to oppose the
change in flux that generated them. It is caused when a conductor is exposed to a changing magnetic
field due to relative motion of the field source and conductor; or due to variations of the field
with time. This can cause a circulating flow of electrons, or a current, within the body of the conductor.
These circulating eddies of current create induced magnetic fields that oppose the change of the original
magnetic field due to Lenz's law, causing repulsive or drag forces between the conductor and the magnet.
The stronger the applied magnetic field, or the greater the electrical conductivity of the conductor,
or the faster the field that the conductor is exposed to changes, then the greater the currents that
are developed and the greater the opposing field.
The term eddy current comes from analogous currents seen in water when dragging an
oar breadth wise localized areas of turbulence known as eddies
give rise to persistent vortices.
Eddy currents, like all electric currents, generate heat as well as electromagnetic forces.
The heat can be harnessed for induction heating. The electromagnetic forces can be used for levitation,
creating movement, or to give a strong braking effect. Eddy currents can also have undesirable effects,
for instance power loss in transformers. In this application, they are minimized with thin plates, by
lamination of conductors or other details of conductor shape.
Self-induced eddy currents are responsible for the skin effect in conductors.
The latter can be used for non-destructive testing of materials for geometry features,
like micro-cracks. A similar effect is the proximity effect, which is caused by externally-induced eddy currents.
Always Ferromagnetic Tube Inspection Eddy Current is best Suitable. |
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What is remote Field Eddy current? |
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The Remote Field Eddy Current (RFEC) inspection technique is a nondestructive method which uses
low frequency AC and through wall transmission to inspect pipes and tubes from the inside. The through wall nature of the
technique allows external and internal defects to be detected with approximately equal sensitivity. |
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The RFEC tool uses a relatively large internal solenoidal exciter coil which is driven with
low frequency AC. A detector or circumferential array of detector coils, is placed near the inside of the pipe wall, but
axially displaced from the exciter by about two pipe diameters. Two distinct coupling paths exist between the exciter and
the detector coils. The direct path, inside the tube, is attenuated rapidly by circumferential eddy currents induced in
the tube's wall. The indirect coupling path originates in the exciter fields which diffuse radially outward through the
wall. At the outer wall, the field spreads rapidly along the tube with little further attenuation. These fields re-diffuse
back through the pipe wall and are the dominant field inside the tube at remote field spacing. Anomalies anywhere in the
indirect path cause changes in the magnitude and phase of the received signal, and can therefore be used to detect defects.
RFEC Inspection use to Inspect carbon Steel tubes.
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What is IRIS: |
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Simply IRIS Ultrasonic Immersion technique. Which uses for Tube Inspection,
Internal rotary inspection system (IRIS) is an ultrasonic method for the nondestructive testing
of pipes and tubes. The IRIS probe is inserted into a tube that is flooded with water, and the
probe is pulled out slowly as the data is displayed and recorded. The ultrasonic beam allows
detection of metal loss from the inside and outside of the tube wall.
The IRIS probe consists of a rotating mirror that directs the ultrasonic beam into the tube wall.
The mirror is driven by a small turbine that is rotated by the pressure of water being pumped in.
As the probe is pulled the spinning motion of the mirror results in a helical scan path.
Specialized NDT services India, Provide Tube Inspection Service with Support of our Agent in Kuwait and Canada.
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Please contact us for Procedure and Rate : enquiry@specializedndt.com |
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