rely on the centrifugal forces to direct the heavier particles radially outward, away from the springs.
Still another design option is to use a cone spring design
that is not susceptible to clogging. In some designs, an elastomer coated cone spring can also eliminate the need for a
dynamic O-ring.
Drive Collar Design
To avoid abrasive wear on the pump shaft, this component is
often manufactured from very hard steel. As a result, typical
seal drive collar designs that use set screws to “bite” into the
shaft are not capable of providing adequate drive and alternative collar designs that rely on wedges to create high clamping
forces against the shaft are required.
Summary
When seal designs are applied to abrasive slurry applications
that properly address the five design considerations noted
above, mechanical seals can provide very reliable sealing performance. Even in the harsh environments of many abrasive
slurry mining applications, seal MTBF will typically exceed 40
months with proper seal design and application. Reliable sealing performance, coupled with reduced operating costs over
packing, are a driving force in application of mechanical seals
Figure 3. Mechanical seal design using a cone spring.
in many M&OP slurry pumps.
Next Month: How can I reduce consumption of seal flush water
going to my packing and mechanical seals?
We invite your questions on sealing issues and will provide best
efforts answers based on FSA publications. Please direct your questions to: sealingquestions@fluidsealing.com.
