Clock of flowing time
The clock of flowing time is a 13 meter high water clock in Berlin's Europa-Center , which extends over three floors. The clock was designed by the French Bernard Gitton and installed in 1982. With this watch, the time is displayed in a circuit using liquid-filled glass spheres, the smallest of which are filled every 144 seconds. A pendulum also swings in the lower half of the clock .
This modern type of water clock shows the passage of minutes and hours every twelve hours. Colored water flows in a system of glass spheres arranged in towers and communicating tubes and indirectly enables the respective time to be displayed. The entire system is always emptied at 1 a.m. and 1 p.m. - only the hour display from 1 a.m. and 1 p.m. remains visible - and the cycle starts again.
In front of the northern entrance of the Europa-Center on Budapester Strasse , the Berlin clock , also known as the set theory clock , is a comparable counterpart of the way the time can also be displayed .
functionality
The clock is basically a pendulum clock . The elapsed time is determined by counting the past oscillations of the pendulum. A mechanical clockwork is used for this in normal pendulum clocks. With this clock, however, the flow of water is used to count the pendulum oscillations. The construction of the watch is designed in such a way that the water flow can fluctuate by up to ± 20% without affecting the accuracy of the watch.
A continuous (but not constant) flow of water flows from the reservoir in the upper area to a container connected to the pendulum, which is sufficient to absorb the water that accumulates during a pendulum movement. The swing time of the pendulum is six seconds. With each pendulum movement, this container releases its contents once into the circuit. At the same time, this water supply serves to maintain the pendulum movement.
The system for counting the pendulum movements made is based on communicating tubes and the principle of the suction lifter . Several sections each in the form of an "N" with rounded corners are used to directly count the pendulum oscillations. The water enters the "N" from the top right and leaves it to the bottom left as soon as the level of the right two limbs rises above the top left tip of the "N". All of the liquid in the “N” is sucked off and taken up by the “N” below.
Due to this construction, the watch is quite tolerant of fluctuations in the fluid supply. The first “N” container overflows as soon as a certain volume of water (V) has flown in . The most tolerant of fluctuations in the inflow is a design in which each container overflows after the second filling and the overflow volume doubles in each stage. The inflow per pendulum oscillation must then be between V / 2 and V , so it can fluctuate by a factor of 2 without affecting the accuracy.
With this clock, this principle is implemented in the first three containers, while the fourth and last container overflows with the third filling. For this, each time the third container is emptied, between a third and half of the overflow volume of the last container must flow in to maintain the accuracy. If the process is correct, the last container will overflow after 24 pendulum oscillations.
While the "N" cascade is running, a container fills above the minute display of the clock, the volume of which corresponds to a display of a little more than two minutes (exactly 144 seconds); After it has been completely filled, the container overflows in the direction of the hourly storage container. When the lower of the four “N” overflows after 144 seconds, a vacuum is generated in the pipe above, which is transferred to the drainage of the filled container above the minute display and empties it into the minute display according to the principle of the suction siphon. The minute column is marked in a two-minute rhythm (glass jags), but is filled in a 144-second rhythm. This slight difference is only visible on closer observation.
After one hour, the (also N-shaped) minute display overflows and triggers the filling of an hour container via a similar suction mechanism. At 1 a.m. and 1 p.m., the hour container is also emptied and the cycle starts again.
The draining water is collected in the lower part of the clock and pumped back into the reservoir in the upper part of the clock at regular intervals (about every ten minutes). This is the only energy input in the entire system.
Details
- There are no superfluous pipes. All tubes of the clock are necessary for the clock to function.
- The sphere for 1 o'clock is not connected to the spheres for the other hours, although the construction gives a different impression. On closer inspection it can be seen that its contents are not connected to the other hour balls. Instead, a thin pipe leads from the “2” directly above it through the middle of the “1” directly to the collecting container in the lower area of the clock.
Web links
- Description on the Europa Center website (archived in January 2019)
Coordinates: 52 ° 30 ′ 16 ″ N , 13 ° 20 ′ 20 ″ E