Case Studies

The Problem

An agro-chemicals manufacturer asked NASH to repair a John Crane 157 coaxial cartridge after the seal failed 3 times in 12 months.

These failures had caused unacceptable disruption to production with associated high maintenance costs.

The Solution

The seal was collected by NASH and returned to the factory for evaluation.

The seal was pressure tested before strip down and leaked outboard. The outboard stationary carbon face flatness was measured and initially appeared to be flat to the required 2-3 helium light bands. However, further tests revealed the face was going out of flat as temperature and pressure increased. This was because the carbon face insert had not been shrunk

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into it's metal holder correctly during a previous repair, causing the face to be unstable.

A new face insert was made and shrunk in to NASH tolerances and procedures. The seal was overhauled and successfully recommissioned in 5 days.

The Benefits

By choosing NASH, the client resolved what had been a protracted mechanical seal problem and quickly restored reactor and plant reliability.