Wear & Tear (2)

After three years of reliable service, Sentinel 7109's cab boiler feed pump decided it was going to play games and started spitting steam out of the steam cylinder end cover joint.

This early photo shows the light green layer between cylinders and the end cover.

June 2011 photo long before putting the pump to work

The material I used for the joint was Klinger's Klingersil C-4400. I'd bought this in 2010. Its spec shows that it can withstand about 23bar pressure at 230degC. All seemed satisfactory as water boils at approximately 230degC when at 19bar pressure.

The next photo shows the effect of three years' use (and possibly the recent heavy frost?).

Comprehensive disintegration of the joint material

There are splits in many places which makes me wonder if there may have been some frost involved but that is speculation.

In retrospect, what is more to the point is that, while the spec shows the joint material is good for 230 degC and 19bar, the steam supply to the pump has passed through the superheater and is likely to be somewhat hotter than the figure I had originally assumed. I'm thus rather surprised it had lasted as this long!

Later in the restoration process, for all steam joints, I'd switched to a higher spec joint material, namely Klinger's Kingergraphite PSM/AS. More details here.

So that's what will be used for the repair.

I can say I now have more (hard-earned) experience!