Steam Department

A busy day with some big ups and downs in the steam shop.  There is not much to see externally and only one photograph this week but this shows a big milestone.  We put water into the boiler for the first time.

The focus was on 1630 and above all on starting to test the newly fitted tubes for leaks.

·         In the morning the focus was on closing every hole below the crown sheet level:

the last remaining wash out plugs were installed, lubricated with graphite paste and tightened down;

the pressure gauges were finally fitted and plumbed in to the boiler;

all remaining flexible stay caps were cleaned, lubricated with graphite paste and tightened down.

·         Just after lunchtime this was done.  We linked up the hoses from the milk car and started pumping.  To be clear, there is no intention to pressurize at this point.  We need to fill and empty the boiler several times before we can apply pressure.  Pressure testing is carried out with water heated to about 100 degrees by circulating thru the pool heater.  It is rather important that we wash out debris such as residual sand blast material before trying to re-circulate the water thru the pump !.  These filling and draining cycles also allow initial testing of the sealing the tubes and other parts of the boiler.  While no external pressure is applied, the boiler is at least 6 feet to the crown sheet so there is a good deal of pressure simply from the depth of water.

The first filling was rather disappointing for those of us who had not seen this done before.  I had expected some leakage from the tubes, where they seal into the sheets, when water was first added but had probably not expected leakage from 30 or more of the small tubes, some of it quite extensive.  On closer review, it indicated some variation in how much we had expanded the tubes at different times.  Interesting, we were not conscious on any great difference as we did the expansion but the water was very revealing.  The smokebox was excellent.  There are no more than 4 tubes there that show any leakage and then no more than a dribble.  Great job by Brian, who did most of this area.  In the firebox, the engineer's side was relatively good while the lower fireman's side had a substantial number of tubes with a lot of leakage.  Clearly we did not get these as tight as other areas.

So we noted the leaks, dumped the water, which came out looking really dirty, and got working.  Brian and others set up the air motor driven expander and worked thru the list of 30 or so small tubes that had been noted with leaks.  At the same time, others worked on a few issues noted such as a weeping plug, a couple of stay caps that had been missed and a check valve that was not fully closed.

A second filling in early evening was very satisfying.  Although there was still a lot of leakage from super heater flues - no surprise as we had not worked these, the improvement in the small tubes was remarkable.  We still had around 8 with minor dribbles but these were generally ones we had not previously noted, probably because the leakage was missed at the first pass due to the far greater leakage from other tubes.  All those that had been worked on after the first test were dry.  In addition the minor leaks other than at tube ends were all now dry.

Water reaches the crown sheet