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Industrial turbo Blowers



Patented SiC-X Dry Run Resistant Bearings



Never run a Magnatex magnetic drive pump dry, but if you do, a Magnatex SiC-X inner magnet bearing system can help.

Increased dry-running capability!

  • Unique materials and manufacturing techniques of our specially treated SiC-X bearings provide a coefficient of friction 1/4 that of SiC.
  • The very low coefficient of friction of our SiC-X bearings results in much less heat being generated in upset or dry-running conditions. SiC-X bearings are more forgiving of dry-running conditions frequently encountered at start-up, during upset conditions or in batch services. Extremely hard surfaces minimize wear and prolong service life; resistance to chemicals is maintained for extended bearing life.

SiC-X Availability
MMP/MMH/MML—Standard
MP/ML/MPH/MPT—Standard
MPL/MLL/MHL—Optional
MAXP—Optional

photo of SiC-X Bearing System
  SiC-Xsm Bearing System

Preliminary Test Results

  • In multiple dry-running tests using an MP220, 1 HP unit with standard SiC bearings, noise developed after a brief period of operation. On disassembly, internal damage was identified. The same pump with the special bearing material operated over 1 hour and 45 minutes with no unusual noise. On disassembly, there was no visible damage.
  • The next test involved running the same pump with the SiC-X bearing material dry for one hour with the suction valve closed. The rear casing temperature reached 260°F. With the pump still operating, the suction valve was then opened, allowing room temperature water to enter the pump. On inspection after the pump continued to operate, no damage or cracks were observed--all parts were in excellent condition.
  • A test at a customer facility was inadvertently run when the suction cap used during shipping was not removed before installation. After running dry for 10 minutes, the pump was inspected and no damage was observed. The pump was reinstalled without the cap and operated as expected.

Test Progression Standard SiC SiC-X
  Coefficient of Friction = 0.39 Coefficient of Friction = 0.099
Operation with a combination of air and liquid; rotation
speed of 19.7ft/sec and weight on bearing of 8.2
lbs.
The bearing surface was abraded with noticeable wear after operating for 10 minutes Bearing was in excellent condition after 10
minutes of operation
Dry-running—no liquid; 19.7 ft/sec, 8.2lbs Bearing damage after 2 seconds of
operation
Bearing was in excellent condition after 80
seconds
Dry-running—no liquid; 15.4 ft/sec, 2.2lbs Bearing damage after 45 seconds of operation Bearing was still in excellent condition after
1 hour and 45 minutes of operation
Heat shock after dry-running 1 hour; poured water at room temperature on bearing which was assumed over 330°F N/A—will not run dry this long Bearing was still in excellent condition; no thermal cracking or heat checking evident
Dry-running—No liquid, inner magnet assembly weight of 22.5 lbs. Bearings destroyed after 2-3 seconds Bearings were in excellent, as new condition, after 1 minute of runtime.
Dry-running—No liquid, inner magnet assembly weight of 22.5 lbs. Bearings destroyed after 2-3 seconds. Shaft sleeve was cracked after 2 minutes of operation. No other permanent damage to the pump was recorded.

 

Liquid Temperature degrees °F Time Degrees of Corrosion (g/m2/hr)
65% HNO3 Boiling 24 Hours 0.003
100% H2SO4 Boiling 24 Hours 0.002
35% HCl Boiling 24 Hours 0.002
30% NaOH Boiling 24 Hours 0.002
100% CH3COOH 158°F 24 Hours 0.000
35% H2O2 Boiling 24 Hours 0.002


In the case of the test application involving air with liquid — an inherently difficult situation for product lubricated bearings— the SiC-X bearing operated continuously for 10 minutes with no cracks or wear. Even with completely dry operation with no liquid whatsoever. Inspection revealed the bearings to still be in good condition after 1 hour 45 minutes.


Conclusions
One of the weak points of ceramic materials is poor response to thermal shock. In our tests, the SiC-X bearing material was unaffected. On inspection the bearings showed no evidence of damage. The results of a similar, though inadvertent, field test where a technician discovered the pump was being operated in a dry-running condition were equally impressive. He stopped the pump and poured liquid on the bearing to cool it off quickly. Even in that situation with the bearing close to the point of being damaged, the SiC-X gave the customer good results. The technician “expected damage” and was surprised to see the SiC-X in good condition.
As indicated in the corrosion testing chart above, SiC-X has comparable performance to that of SiC as shown in various literature sources for the listed chemicals.


Summary
From our testing and analysis, it is clear that the SiC-X provides good results when used in magnetically-driven pumps, especially for troublesome short term startup dry-running conditions. You can expect better performance in the case of upset conditions and other temporary dry-running situations, delaying or reducing bearing damage whereas a catastrophic bearing failure would have immediately occurred with standard SiC. When used in conjunction with a power monitor and/or vibration monitoring equipment, sudden, catastrophic mechanical failure of magnetic drive pumps can be a thing of the past. It should be noted that the heavier the inner magnet assembly is, the shorter the dry running duration capability.
The values in the above charts are from actual test results and are considered reliable, though we cannot guarantee similar results.

 

 

ISO 9001:2008 Certification
ISO 9001:2008 Certification