Box elevator of the channel with coal of Somersetshire

The elevator with box of the channel with coal of Somersetshire (in English: Somersetshire Coal Canal box lock ) is a Ship lift which was set up at the 18th century on the Canal with coal of Somersetshire (disappeared today,), in the south of the town of Bath in England. It was built to compensate for the difference in level with Combe Hay, which was of 41 meters (135 feet). Its originator was the engineer Robert Weldon (1754-1810).

This astonishing work for the time, worthy of imaginary creations of Jules Verne, is sometimes qualified on the spot “underwater for boats ”.

The details of the machinery and the exact localization of the work remain unknown to date.

The French literature of the time (in particular Joseph-Michel Dutens) evokes the work under the name of " lock with flotteur".

Principle of the elevator

Diagram of the box and its cistern

Structure of the building

The heart of the device is a great volume filled with water, with the smooth and vertical walls, called cistern. A channel arrives at its top, on one of small with dimensions of the oblong section. At the bottom of the cistern, a door, also located on one of small with dimensions of the oblong section, opens on another channel.

Is placed in the cistern, a box length slightly lower than the greatest width of the cistern. The buoyancy of this box is close to that of water, in such way that it can be easily gone up or gone down within the cistern.

Operation

A boat arrives by the higher channel, and enters the tight box, which one closes. The box is descended at the bottom from the cistern using a toothed rack. The lower door of the cistern is then opened, which “plates” instantaneously the box on the level of its door against this opening. The door of the box can now be open and let leave the boat. It is enough to close again the two doors and to let reassemble the box to start again the operation.

Diagram of operation

History of the channel and the elevator

The Somersetshire Coal Canal (SCC) was authorized by the Parliament in April 1794. It was built at the instigation of the owners of the mines with coal of Sommerset north, with an aim of conveying in the area of Bath coal, in place is place of transport by cart, only existing before. The threat of the competition of the coal of the Wales consolidated them in this decision.

The channel connected of is in west the aqueduct of Dundas (Canal Kennet & Avon) with the basin of Paulton. A secondary branch also allowed a connection with Radstock, in the south.

The channel was to include/understand many works of art, primarily bridges and locks. The major difficulty was at Combe Hay, with uneven of 41 meters to be compensated.

The engineer Robert Weldon had carried out in 1792 a device of demonstration of box elevator on scale 1/2 on the Canal Ketley. The work would have been inspired in the writings of 1777 of Erasme Darwin, grandfather of Charles Darwin, originating in Lichfield just like Robert Weldon.

The unevenness was to be caught up with by three successive box elevators dug in the hill. The construction of the first elevator began in spring 1796, and the tests took place later two years. At the end of six tests, the experiment was not considered to be conclusive, in particular as for its technical sides (masonry had inflated with moisture), but also at the costs of construction. This first elevator already had cost 4.582 £ instead of the 1200 £ envisaged. The work, as well as the two others in the course of construction, were given up and embanked.

It was replaced by a railway tilted plan in 1801: coal was conditioned in Conteneur S of a ton, which was put by 3 on the coaches which went down towards the lower channel by gravity.

This tilted plan was not a long time active because of sound too poor yield. In April 1805, a series of 22 locks was brought into service for the passage of the barges. A pump with vapor able to go up 5.500 tons of water per day was installed to compensate for the enormous water losses generated by these locks.

In the Années 1820, the channel made it possible to transport up to 100.000 tons of coal per annum, which did of it one of most important country. The railroad carried a fatal blow however to him. It was definitively abandoned in 1898.

Features of the box elevator of the channel with coal of Somersetshire

Dimensions

Room:

height: 20 meters (66 feet)
width: from 3 to 6 meters (from 11 to 20 feet)
length: 27 meters (88 feet)
toothed rack: 14 meters (46 feet)

rotation: approximately 7 minutes

Tests

no1 : February 1798: cracks
no2: June 1798: success
NO3: April 1799: success
no4: April 1799: success, in the presence of the Prince de Galles
NO5: April 1799: success, transport of 60 passengers
no6: May 1799: box blocked by a projecting stone

The channel nowadays

Given up since more than one century, this one is gradually turned over to nature. Certain sections were however rehabilitated for tourism. The locks, which for the majority had been built out of wood, for a long time disappeared.

Association “ Somersetshire Coal Canal Society ” (SCC 2) is given the responsability to preserve the memory of the channel, of the rehabilitation of certain sections and of the works of Article It also conducts campaigns of excavations in order to find the exact place where was the box elevator.

Other achievements

Towards 1817 the Regents Channel Company built a device similar to the current site of the lock of Camden ( ), in the north of London. The reason of this device was also the problems of water provisioning, although the unevenness is less large than in Combe Hay. The device was also quickly replaced by conventional locks. There does not exist example of commercial exploitation successful of this device.

References and notes

Klew, Kenneth R (1977): Somersetshire Coal Channel and Railways. David and Charles, Abbot Newton, the U.K. ISBN 0-7153-4792-6.
Uhlemann, Hans-Joachim (2002): " Canal Lifts and Incline the World" off; Boarding school, Horsham, the U.K. ISBN 0-9543181-1-0.

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