AMRI BUTTERFLY VALVE

The engine being run for the first time after restoration by volunteers.
Video by Kailey Ross.
Grab Dredger “Sandchime” and her engine, was built by William Simon & Co's, Renfrew, for the Department of Agriculture & Fisheries (Scotland).
Yard No. 794. She was launched 14/03/1952Fleet No. 303091
190 ton, 105ft long, 24ft 6in beam, draught 8ft 9in.
Propulsion by a triple expansion steam engine of some 12 tons weight, producing 234 HP.
Max speed 6.5 knot.
She operated around Scottish coasts, ports & harbours until 1972.( Department of Agriculture & Fisheries Scotland)

Engine Restoration -
The engine, a three cylinder triple expansion, was purchased using a grant.
The restoration was undertaken by a group of volunteers at the Scottish Maritime Museum Irvine Scotland. Work started in April 2010. This was the first triple expansion engine undertaken for restoration by the volunteer group.
The “Sandchime” engine is missing 3 top cylinder relief valves, hand turning gear, 4 oiler pipes, 6 cocks from the sea water cooling rail,and 5 bearing cooling spouts.
During the removal of asbestos from the engine, 3 cladding panels and 4 oil pipes went astray. The cladding panels shall be made by the volunteers.
As the Turning Gear drive was missing a “Heath Robinson” version was installed. This comprised of a crucifix made from strap steel bolted to the crank shaft flange. An eye bolt secured to the top of the engine from which a Ľ ton chain block was suspended, the hook of the block was engaged in “bow shackles” fitted at the ends of the crucifix. This allowed the engine to be turned as each part was replaced ensuring a free engine at every stage of the rebuild.
The three Pistons and the HP piston valve were seized. The cylinder covers had to be removed. An attempt was made to pull the middle piston using 30 ton jacks, this failed.
The Connecting rods, X heads, big ends and the Stephenson linkage from the HP piston valve were removed. The cylinders then had easing oil poured in and left to soak the pistons were eventually freed with a combination of jacking from the top and chain blocks from the bottom.
The application of heat from a gas torch was required to free the HP piston valve.
Because of this, the ensuing work and restoration extended the project by about 6 months.
The first major part of the restoration was the pump unit. Air pump, 2 auxiliary positive displacement plunger pumps ,associated valves, air bottles and pipework.
The pump unit was the last major component to be replaced as work could not easily be carried out on the LP rods, X head and valve linkage when it was in place. The pump unit weighs approx ˝ ton.
After the HP piston valve and pistons was freed (HP valve removed completely) work was mainly stripping, cleaning, recording and reassembly.
There are 6 Mechanical steam glands, (one to each piston and valve rod) These were in poor condition with the compression springs mainly corroded away. A source was found locally who manufactured the springs for us at a reasonable cost. (Irvine Spring Co.). There are 20 springs to each set of packing. The packing was manufactured by “ The United States Metallic Packing Co. Ltd.” Bradford.
To facilitate the refitting of the valve rod steam glands the Stephenson linkage and guide bush support brackets were removed on all 3 valves.
The Crank Shaft was lifted out and the main bearings scraped and cleaned (5 of)
Replacement of the X heads, connecting rods, Stephenson linkage and eccentrics for the valves was carried out HP to LP.
The heavy lifts were the crank shaft, cylinder covers, (especially the LP) and the pump unit (comprising Air Pump, Auxiliary Bilge Pump, Auxiliary Feed Pump), these were remounted as one unit.
It should be noted that the lifting gear available to the volunteers is an “A” Frame with a ˝ ton chain block attached, and a 2 ton engine lifter. As the engine lifter has a max height of 6 feet and the “A” frame just clears the top of the engine, ingenuity was at the fore.
Stripping the old Paint and rust from the engine was progressive, i.e. Carried out as parts were removed. The engine being a triple expansion and quite small is very “busy” if the painting had been left to the end of the refit the same effect could not have been achieved.
When the engine arrived in the “Linthouse” it was painted red, white and blue, one would assume at some time there was a patriotic engine keeper. On stripping the pumps it was found the original colour was cream. “Champagne”. A & L Paints of Kilmarnock matched the paint chips to a British Standard. The base was black.
The numerous Valves and Cocks were stripped, cleaned, where necessary repacked / jointed and replaced.
The main steam inlet valve was fully refitted and shot blasted of site. It should be noted that the steam inlet valve has an integral throttle valve (butterfly valve). This allows the speed of the engine to be controlled while the inlet valve is fully open (prevents “wire drawing” of

Exploded drawing view of a butterfly valve. Each part made with Autodesk Inventor for the class Advanced CAD, April 2008.