Hoffmann Kiln of Eclipse Brickworks

Cadw's description

Location

W side of the former Llanelli and Mynydd Mawr Railway, 1/2 km SE of Horeb. Site of siding with a passing loop and remains of brickwork loading platform at E. Site of moulding & drying shed and ruin of engine house (for tramway to claypit) at E.

History

An almost completely surviving 16-chamber Hoffmann brick kiln, built by the former Horeb, Star, Blackthorn or Eclipse brickworks, and dating from 1907. It is believed to be the only example surviving in Wales. The bricks were moulded in the shed to the west, fired, and despatched to the railway siding to the east.

The Hoffmann kiln was an important innovation in continuous firing of bricks (also used in the manufacture of Portland cement), a multi-chamber kiln in which the fire advanced one chamber each day (controlled by the pouring in of fuel through the roof chutes). The loading and unloading took place daily in the chamber opposite to the fire. The air current entered where the bricks were being stacked, encircled the kiln, and exited through underground flues to the chimney. The 'green' bricks in the hot air ahead of the firing and the fired bricks in the cold air behind it were enabled to heat or cool gradually with greatly reduced risk of failure. The earliest Hoffmann kilns were circular with a central chimney, the later ones were on a racetrack plan, which had the potential of being extended if required.

The moulding and drying shed serving the kiln has almost totally disappeared, but there are ruins to the NW of the kiln of an engine house. The claypit was about 100 m to the NW, and the engine house probably worked a tramway with chains.

Exterior

The kiln is of the late type with racetrack plan, round-ended internally but square ended with slight chamfers externally, about 12 m by 40 m., and with chimney external to the kiln on the W side; the kiln about 3 m high, flat topped, with a strongly battered profile. Vitrified red brick construction externally. Two-ring arches to all the access doorways. One access arch has collapsed, the others are all intact. There was originally a roof over the whole kiln (seen in RAF photos), evidence of which survives on the side of the chimney.

Interior

Four of the chambers are in the curved ends, the others in the straight sides. A typical chamber is about 4 m square with a low elliptical vaulted roof about 2 m high; 15 fuel-chutes formed with special firebricks in the roof, arched flues to the centre and to the perimeter, and a charging doorway. Brick paving. Each chamber is separated by a deep rib of brickwork from its neighbours. Between the ribs the vault is of firebrick, and the fill between the vault and the flat top is of earth and rubble.

Reason for designation

Listed as rare and virtually complete example of a Hoffmann kiln, with substantial accompanying remains of ancillary structures.

Scheduled Ancient Monument Cm 281