Magnaflux 2461 Operational manual

Revised July 2014
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Page | 1
CENTRIFUGE TUBES
GENERAL DESCRIPTION
Magnaflux®Centrifuge Tubes are used to monitor the concentration of magnetic particles and the level of
contamination in Magnaglo®fluorescent and Magnavis®visible baths.
BATH STRENGTH
The amount of magnetic particles per gallon of fluid in the inspection bath is called its strength or
concentration. If the bath concentration is below recommended strength, weak particle indications will be
produced or possibly no indication will appear; therefore, defects will not be detected. If there are too many
particles in the bath, indications may be masked by heavy background buildup. The usable limits of bath
strength are quite broad, but for consistent results the bath strength should be maintained constant at all
times.
A light bath strength usually forms good indications on deep cracks, but a heavier particle concentration will
show fine defects better. The bath concentration, which will best detect all defects, should be determined and
held constant. Bath strength should be checked at least once each day.
After the entire bath has been thoroughly mixed and agitated, it is essential to check it for strength. The most
widely used method is by gravity settling in a graduated ASTM pear shaped centrifuge tube.
PART NO.
PRODUCT
MEASUREMENTS PRINTED ON TUBES
2461
7C/9C Visible
1.5 mil in .10 ml graduations
8493
14A, 14AM and 20B Fluorescent
1.0 ml in .05 ml graduations
507923 MG410 and MG3410 0.2 ml in .01 ml graduations
2461
507923
1837A

Revised July 2014
www.magnaflux.com
Page | 2
DAILY INSTRUCTIONS (INCLUDING NEW BATH)
1. Let pump motor run for several minutes to agitate the suspension
2. Flow the bath mixture through hose and nozzle for a few moments to clear hose.
3. Fill the centrifuge tube to the 100 ml line.
4. Place the tube in the stand at a location free from vibration and let stand for 30 minutes for a water
bath and 60 minutes for an oil bath to allow particles to settle out.
The gravity settling method applies to either oil or water suspension. In hot weather the water bath should be
checked more often as is it more volatile than oil. Therefore, as water is lost by evaporation, it must be
replaced.
The settled particles (measured in ml) in the bottom of the tube indicate the amount of magnetic particles in
suspension. A UV light, such as the Magnaflux® ZB-100F Portable Black Light, must be used for fluorescent
particles.
Do not include dirt particles in your centrifuge tube readings. They usually settle on the top of the magnetic
particles. Dirt will not fluoresce under a black light.
In visible particles, the appearance of dirt is very different than that of the particles. Dirt will be coarser and
irregular in shape. See illustrations on page 3 for recommended settling volume.
BATH MAINTENANCE TIPS
To maintain proper bath suspension during inspection requires that it be agitated prior to and while the bath is
in use. The agitator pipe should be removed and thoroughly cleaned monthly or more often, if needed. Also,
check area where sump screen connects to tank, clean and remove any foreign material that may restrict
flow.
Constant use of the bath requires a daily check for evaporation of oil or water, loss of particles due to carry off
and contamination. Eventually the bath will become so contaminated by dirt, lint, oil or other foreign material
that efficient formation of indications will become impossible.
Contamination can be checked by noting the amount of foreign material that settles out with the particles in
the centrifuge tube. Covering equipment, when not in use, will reduce contamination and evaporation.

Revised July 2014
www.magnaflux.com
Page | 3
SPECIFICATIONS COMPLIANCE
ASTM E709-08 (Sections 20.6.1 & X5)
ASTM E1444/E1444M-12 (Section 7.2.1)
BPVC (Section V, Article 7: T-765)