Pipes
The lanes consist of steel pipes of 65 mm bore and wall thickness of 2.5–3 mm. The pipes are connected with tight couplers 14 cm long to ensure perfect coaxial alignment and then welded together, ensuring air-tightness. To prevent dispersion current from causing excess corrosion, ceramic insulators are inserted between the pipe segments at some places. Pipes buried underground are protected from the outside by a layer of fiberglass, wound around at increased temperature and coated with hot asphalt. The pipeline is typically buried under the Prague sidewalks 80–120 cm deep. Inside buildings and in the Prague trunk conduit network the pipes simply are coated with anti-corrosive paint.
The minimum bend radius is 250 cm for underground pipes, but 300 cm is the most commonly used radius. Inside buildings a bend radius as low as 200 cm is allowed. The bends are made of special annealed pipes at normal temperature, using a custom-made bender.
A signaling cable is laid along with the pipe, enabling communication with the track components.
The lane segments are equipped with dumb wells, where the pipeline can be opened and inspected, or a stuck capsule removed. For this purpose a heavier capsule can be sent at a pressure of up to 30 atm, knocking the stuck capsule out.
Read more about this topic: Prague Pneumatic Post
Famous quotes containing the word pipes:
“Next, pipes are lit by those who smoke, and veils are donned by those who have them, and we hastily examine and dry our plants, anoint our faces and hands, and go to bed—and—the mosquitoes.”
—Henry David Thoreau (1817–1862)
“They were pipes of pagan mirth,
And the world had found new terms of worth.
He laid him down on the sunburned earth
And raveled a flower and looked away.
Play? Play? What should he play?”
—Robert Frost (1874–1963)
“Because the Muses never knew their pains.
They boast their peasants’ pipes, but peasants now
Resign their pipes and plod behind the plough;”
—George Crabbe (1754–1832)