Know what the rubber is up against
A seal failed early on a pump handling an alkaline liquid. I sent the damaged seal back with eight photographs.
The returned rubber showed signs of chemical attack. A litmus test on the seal came out around pH 10, so for the replacement I changed the rubber to EPDM.
The next move starts with understanding the problem, not choosing another seal from a catalogue. In this case, the returned rubber and the litmus test gave me something to work from.
Check the liquid before you choose the rubber. Do the thinking before the next seal goes in.
Solutions related to this article
If this failure mode sounds familiar, these are the products and services that usually fix it.
- Encapsulated O-RingsFEP or PTFE jacketed O-rings for fluids that destroy standard elastomers.View details
- FFKM O-RingsPerfluoroelastomer O-rings for aggressive chemistry and temperatures to 325C.View details
- Cartridge SealsPre assembled seal units that remove setting errors on pumps, mixers and agitators.View details
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Founder and Mechanical Seal Specialist, Acumen Seals & Pumps
Published on 2026-10-15
45 years in engineering and 36 years in sealing. Andrew specifies, supplies and troubleshoots mechanical seals, FFKM elastomers and pump sealing systems for UK industry.
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