Publication Account
Date 1986
Event ID 1017663
Category Descriptive Accounts
Type Publication Account
Permalink http://canmore.org.uk/event/1017663
Now preserved as an industrial monument, this giant beam-engine at the former Prestongrange colliery is a worthy tribute in Scotland to its builders, the famous engineering firm of Harvey & Co., of Hayle, Cornwall.Built in 1874 to pump water from a depth of 800ft (244m), it is a single-acting non-rotative beam-engine of a type once extensively used for draining mines in Britain, but notably in Cornwall, where the majority were manufactured. In common with other Cornish engines, its distinctive feature is the nature of the cycle, which in essence uses high pressure steam, controlled by a system of cut-off levers and valves, in such a way as to give a high degree of economy.
The engine forms an integral part of the engine-house, and the massive cast-iron beam, which weighs approximately 30 tons (30.38 tonnes), must presumably have been raised to its height of 27 ft (8.23m) by means of jacks as the work proceeded, or winched into position subsequently on timber shores. The beam is 33 ft (10'06 m) long and 6 ft 4 in (1.93m) deep at the centre, with the fulcrum located eccentrically at a point 18ft (5.49m) from the steam end, giving the latter a stroke of 12 ft (3.66m) and the pump-rams one of 10 ft (3.05m). The engine was equipped with a steam cylinder of 70 in (1'78 m) diameter and developed a normal working speed of three and a half strokes per minute and a water-pumping capacity of 650 gallons (2,955 litres) per minute. It was modified in 1895 to work larger shaft-pumps with rods of 23 in-square (0.58m) Oregon pine, for which purpose an ingenious overhead strengthening truss had to be contrived on the beam. The engine continued to be fully operational until 1954 and is the centre-piece of a historical site devoted to the Scottish coal industry.
Information from ‘Monuments of Industry: An Illustrated Historical Record’, (1986).
