Thanks to David Davies of The Robey Trust, who supplied the following information about this particular boiler.

This boiler is quite interesting. The records we hold are quite brief:

Boiler number 8954 8LB (which means, I supect, 8hp loco-type boiler)

Machinery Order Number 3215. Delivered 19th May 1885. The MON shows it is one of a series of 30 (8937 to 8966) all delivered throughout May that year to one customer. This indicates they were building one per day, as well as all the other stuff going on.

So, it appears it only ever was a portable boiler, a product Robeys made for over a century. Most were supplied for steam sterilising in market gardens, but quite a few went to dockyards to provide a portable steam supply to auxilliaries aboard ship to save firing up the main boilers during refitting.

The single row of longitudinal rivets seems to indicate that the boiler pressure would have been 50 lbs/sq/in or not much more. The double curve of the upper throatplate flange is a Victorian design feature, and the rest of it exhibits typical Robey features of the day. However, what the large 'manhole' in the top is for, from the photo, I cannot say.

There seems to be a lockup valve at the back, and typically a Salter valve should also be present.

I would say that of the 17 portable boilers we know of in the UK, this is the oldest.

Please click here for The Robey Trust website