File:Fire Fighting Appliances Gilbert 1969 Plate 21.jpg

English: Merryweather steam fire engine 1885. This model (Scale 1:4.8) shows the construction of a large Merryweather steam fire engine such as was used on docks and other large areas of warehouse property. This engine is a development of the Sutherland and embodies improvements patented by Messrs H. Merryweather and C. J. W. Jakeman in 1880.

The pumping machinery consists of two horizontal steam cylinders 7 in (17.8 cm) diameter by 7 in stroke, and two double-acting horizontal piston pumps 5 in (12:7 cm) diameter The steam pistons are directly connected with the water pistons by common piston rods. Nearly all the engines of this type, though fitted with interconnected cranks, were without flywheels, and the arrangement shown in the model, which has a flywheel, was only used for one engine. A large copper air vessel is placed on top of the delivery chamber, and a small one on the suction chamber to give a steady flow in the pipes.

The engine delivered 450 gallons (2,000 1) per min, and with a 1:5 in (38 mm) nozzle the jet reached a height of 190 ft (60 m). Steam was raised to the full working pressure in ten minutes from the time of lighting the fire. Plate 21 from Fire fighting appliances, the descriptive catalogue of the collection in the Science Museum, London.