Following on from the Boiler test, and a quick trial we identified just over 20 items that needed some attention. So a week later, with all these items fixed (from leaking valves to painting and plating valve gear components), we are ready to try again. Continue reading →
Having “finished” and tested my engine there were a final set of issues that I suggest you keep an eye on:
Piston Rod Lubrication Fitting Clash: The drawings show the small-end and cross head lubrication is achieved via drillings at the top of the piston rods. There is no indication of how oil is delivered to these drillings. I have arranged this using small-bore flexible nylon tube and push fittings. I installed a small elbow into the feed hole to allow the push fittings to point between the bores. However, space is very limited here, being close under the lower cylinder covers and stuffing box glands. When I packed the glands I found that as these sat slightly lower they clashed with the oil feeds at TDC. I can see no way to move the oil feeds. So I resorted to machining away some of the bolting flange of the stuffing-box glands next to the columns. This has worked, but clearances here are tight.
Air Pump Drain Modification: the drawings show a simple drain plug screwed into the bottom of the air pump body. In my design of pump drives this is hard to reach, and having a circulating pump exhausting into the condenser, you can get into the situation where the condenser becomes full of condensate if the main engine/air pump is not running. So I have brought this drain out to a simple taper cock. This just makes things a bit easier.
Pinning the Drop Arms: During early testing I found the drop arms had a tendency to slip on the weighshaft. So I installed small taper pins to secure them.
Reversing Lever Clash: This was just me not spotting a problem earlier. I fitted the weighshaft at the top of the column position. On final installation I discovered the level collides with the exhaust pipe in full-ahead. Just keep an eye open. 🙂
Well the 10th November 2017 marks a major milestone – the boiler passed its initial inspection and steam test, and is now certified for use. (big smiles all round).
Sadly, everything was too frenetic to take pictures during the steam test – but here it is just before we pressed go!
John, our inspector from SBAS Ltd (the SBA’s Boiler Inspecting Company) had been booked to arrive at 3:00pm – at 9:00am I set about final sealing of the try-cocks on the sight gauge – at 1:30pm I nearly called to cancel the appointment as no amount of fiddling and fitting would make them seal, with a constant drip from each of them at anything above 50psi 😦 Continue reading →
Work on the Boiler continues with the finishing and installing of the Economiser (pre-heats the incoming water to the boiler using waste heat from just before the flue) and the Superheater (adds energy to the steam on the way to the engine, again using waste heat from the flue gasses.
Milling and Drilling the Econo/Superheater Headers
As noted in the last post, I decided to mill the recesses in the two halves of the headers, as there is a lot of metal to shift, and with the “ripping” milling cutters this was by far quicker. (some pics)….
While we await the 600+ cut and bent boiler tubes from the other members of the “Boiler Collective” beavering away in Sussex, we went back to the engine to try and close off the final list of “to do” jobs….
I think Cleading is the official word for this, even though WordPress objects! Continue reading →
While we wait for the plasma cut boiler plates and housing to arrive I went back to a job that’s needed doing for a while on the engine; the Lubricator.
Approaches to lubrication
There are several approaches to lubricating a steam engine, from a hand-held oil can (tends to be a bit erratic, and you chop the end of the spout off in moving parts) thru oil wicks, to pumped lubrication. I felt that a pumped system was the way to go.
There are 11 bearings that need lubrication in the engine (3 main bearings, 2 big ends, 2 little ends/crossheads, and 4 eccentrics). Actually, there is cylinder lubrication as well, but we are going to deal with that via a separate displacement lubricator which injects oil into the incoming steam (a sort of 19-century “posi-lub”! Continue reading →