Montech water wedge lift
The water wedge lift Montech ( French Pente d'eau de Montech ) is a boat lift on the Canal latéral à la Garonne in the village of Montech in the French department of Tarn-et-Garonne in southwest France. The system, designed by Jean Aubert as a pilot project, was put into operation in July 1974 as the world's first water wedge lift . In addition to this system, there is only the Fonserannes water wedge lift .
The water wedge lift was built parallel to a lock staircase made up of five successive locks. The ships, which are up to 40 m long, overcome a height difference of 13.30 m in about 20 minutes. The passage via the lock staircase takes 65 minutes, the length of the boats is limited to 30.50 m.
After an engine failure in one of the two drive units, the elevator has been out of service since May 2009. Since then, only the lock stairs have been available for shipping. Work on the reconstruction of the facility is planned to begin in 2018 [obsolete] . It should initially be made accessible from a touristic point of view, but in the long term it should be made functional again.
Details of the elevator
The water wedge lift Montech consists of
- stationary parts
- concrete channel, which leads straight up a slope with a constant cross-section,
- Barrier gate at the bottom of the gutter
- Barrier gate at the top of the channel ( sluice gate )
- and the lifting vehicle with
- One diesel-powered locomotive on each side of the concrete channel, which are rigidly connected to one another via two cross beams that extend over the canal,
- a water gate that shuts off the water wedge in the channel downhill, at the end of the lifting vehicle on the valley side, and
- a horizontal sliding bar - a little uphill in front of the water gate - to moor the ship
The two diesel-electric powered 4-axle traction vehicles produce an output of 1,000 hp each. Each axle is driven and has two profiled pneumatic tires about 1.80 m high . The pair of vehicles, which are coupled in parallel to each other, will drive up and down the two concrete road embankments on both sides of the channel. The 1500 m³ water wedge is moved at a speed of 4.5 km / h.
The precise guidance of each of the two locomotives is carried out by means of a concrete rail protruding from the roadway, which extends along the entire roadway and has a square profile 40 cm wide and high. It is arranged so that it is located between the right and left drive wheels of the locomotive. It has horizontally arranged pairs of guide wheels close to the ground between the first and second and between the penultimate and last axis, which, lying against the side surfaces of the rails, take them into their center.
The locomotives have centrally sprung buffers at both ends. A sequence of six widening white marking fields on a rail allows a precise approach to the lower end position by aiming from the command posts of the vehicles that are only located above the water side. The vehicles are labeled with foil on the underwater front, where they are completely windowless: Logo VNF on a water wave and underneath in italics “Voies Navigables de France”. The signs on the side walls identify the companies CEM , EMH , Poyaud and SGTE as designers . The controls of the lifting vehicle are located in the driver's cab of the southern motor vehicle.
On the canal, which arrives as underwater at the elevator, a shut-off gate is a very similarly shaped and articulated water gate as on the pair of locomotives, which closes the water wedge. The swivel arms of both gates are each mounted on the valley side in a swivel joint with a horizontal axis a few meters above the water level. When the long wedge is pushed away, its large volume does not flow from the underwater, but only the little water that runs through the leak between the water gate and the canal wall. More water then runs through the wedge water gate, as this cannot seal as well as it slides along the channel. The water volume of the wedge is therefore continuously supplemented by a regulated flow from the headwater.
When a ship enters the lift from underwater, the fixed lower shut-off gate must be open and the water gate of the lifting vehicle (on the rigid connecting beam of the pair of locomotives) and the mooring beam must be raised so that the clear passage height for the (possibly partially lowered) superstructures of the Ship is sufficient. The ship (or several within a limited length) then stops in the channel, the mooring beam is lowered hydraulically behind the ship by rotation and then dips a little into the water. The ship is lashed to this beam from which a row of fenders hang. Two jaws, which are mounted on the beam near the channel wall in vertical axes, can be hydraulically pressed diagonally against the ship in order to tension the lashing and to align the ship with clear channel walls so that it does not touch the ship when it is lifted.
After the water wedge has been isolated by lowering the water gate, the lifting journey can begin. The entire construction on the pair of locomotives pushes the water wedge with the ship floating on it up the rising gully via the water gate until the water level of the wedge has reached the headwater and the gate on the headwater can be opened to allow the ship to exit.
A descent of the water wedge including the ship releases a lot of potential energy in the locomotives, which probably overtaxes the thermal output of the drum brakes on the wheels. The electric drive motors are therefore probably switched as generators and feed braking resistors that burn the electrical energy. According to Archimedes, a floating ship displaces exactly its own mass of water, i.e. does not increase the total mass, but in smaller ships the water wedge could be kept a little smaller on the way in order to save upward drive or downward braking energy. An empty trip without a ship can be driven extra easily with the water gate raised and therefore without any water wedge.
At the mobile water gate, the line of the seal on the channel wall appears to be set back in a wedge shape - more at the top - opposite a sign. The shield could act as an emergency buffer against the ship if the mooring beam should break. An air-filled cavity behind the shield reduces the mass of the water wedge that has to be moved. When the door is closed, the angle of the sealing line in relation to the perpendicular or in relation to the vertical on the swivel arm produces a hydrostatic pressure force that presses the door against the channel bottom.
Technical specifications
- Level difference: 13.3 m
- Slope of the gutter: 3%
- Length of the channel: 443 m
- Width of the gutter: 6 m
- Height of the gutter walls: 4.35 m
- Water height at the head: 2.50 m
- Water height at the lifting device: 3.75 m
- Length of the water wedge: 125 m
- Moved water volume: 1500 m³
- Power of the locomotives: 2 × 1000 HP
- Length, width and tonnage of the boats: 38.5 m / 5.50 m / 250 t
Coordinates: 43 ° 58 ′ 13 ″ N , 1 ° 13 ′ 39 ″ E
Web links
- Montech water wedge lift. In: Structurae
- Detailed information. Archived from the original on August 6, 2012 ; Retrieved October 22, 2017 (French).
- Short video report (French)
Individual evidence
- ↑ a b c d Information boards at the water wedge lift
- ↑ AVIS A LA BATELLERIE N ° FR / 2009/04257. In: Service de la navigation du Sud-Ouest. November 17, 2009, accessed October 22, 2017 (French).
- ↑ AVIS A LA BATELLERIE N ° FR / 2009/01835. In: Service de la navigation du Sud-Ouest. May 28, 2009, accessed October 22, 2017 (French).