Slurry pumps used in the mining industry often carry liquid mixed with highly abrasive solids and the task of preventing this corrosive material from leaking onto the shaft and outside the pump falls on the gland’s seals. Slurry pumps themselves are also exposed to corrosion, but these are often designed with sacrificial material and replaceable spare parts to withstand the wear. It is the seals that can be the weakest link, according to Raj Jadow, national key account manager at Seal Innovations.
“Three basic types of problems can lead to failure of gland seals in slurry pumps,” says Raj.
“The first one is corrosion. When you have a hyper saline or chemical environment, it will lead to seal corrosion. This problem can be aggravated if there’s erosion in pump parts, leading to material crystallising around sealing surfaces.”
The second major cause of failure for gland seals, according to Raj, is wear and tear.
“This is often caused due to adulteration of the sealing chamber by slurry being pumped through insufficient flow passage, which in turn leads to higher water pressure. It can also be caused through fluid crystallisation or through excessive force applied between sealing faces by over tightening of the gland follower,” he says.
Lastly, Raj says gland seals are susceptible to failure due to excessive friction, caused by over-tightening of the gland seal.
“Gland sealed pumps are designed to leak, so they should be allowed to drip so that the flushing water can cool the gland. If too much pressure is inserted to achieve zero leak, it creates too much friction in the seal,” Raj says.
So, what is the real fix for preventing untimely seal failures in slurry pumps? Raj suggests a combination of selecting the right seal material, correct installation, pump start-up procedure, optimum pressure and flow of clean flush water. Seal Innovations also has hybrid solutions that can help.
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