Elevators #3
After finishing with the Tower's top we may lastly have a look at the elevtors serving the 3rd floor.
The system was develloped by French engineer Félix Léon Edoux (1827- 1910), an old schoolmate of M. Eiffel.
Biggest problem was the huge distance they had to deal with: 160,4 meters.
At those times it simply wasn't possible to handle such a distance with just one elevator. So M. Edoux had a clever idea: He divided the distance into two parts. Two cabins connected by cables, suspended from a system of wheels on top of the Tower. One cabin served the upper half of the distance while at the same time the other cabin served the lower part.
At their "meeting point" people had to change cabins. This was done at the Plancher Intermédiaire (mezzanine) which we already know.
Worked like this:
Let's first have a look at the wheels carrying the cabins. They were attached to one of the Poutres en diagonale which we got to know in the last chapter:
Right at the moment the cabins are arranged at their meeting point at the Plancher Intermediaire (left cabin goes up):
The cabins were led along some rails which had been supperted by a system of so called "Poteau Guides":
The whole system was expected to be quite sensitive to wind power, therefor the rails were additionally protected by some tubes.
Those tubes got some spiral structure which should stabilize the whole thing additionally:
The left cabin was placed on top of two long hydraulic cylinders containing a piston each, lifting the cabin over the whole distance of 80,2 meters to the third floor, while at the same time gravity made the right cabin descend to the second floor:
To drive the system a huge water tank was installed right below the 3rd floor. In most of Mr. Eiffels drawings this is called RE(servoir) 3:
... being connected with the machine room on bottom of the Southern pillar:
A second huge water tank (RE4) was installed at the mezzanine:
... as well being connected with the machine room:
Missing link is a so called distributor, connecting both RE3 and RE4 with the hydraulic cylinders:
The whole system works like this:
Imagine the both cabins being at their meeting point - this means the pistons are completely within the hydraulic cylinders. The upper tank is full, the lower tank (more or less) empty.
To start the elevator a conductor (placed at the mezzanine) opens a valve, and water begins to flow from RE3 into the hydraulic cylinders, lifting the pistons and the upper cabin.
When the cabin reaches its highest level (3rd floor) the hydraulic cylinders are filled with water.
To make the cabin go down the conductor closes the valve, opens another one, and the water flows from the cylinders into RE4, from there back to the machine room.
As said the conductor was placed at the mezzanine. He had a small cabin there:
... which at least was protected against bad weather:
Within the Southern pillars machine room two pumps ("Pompes Worthington") had the job to keep the upper tank (RE3) constantly filled with water:
