The Pirk dam in the Vogtland district of Saxony has received two new annular piston valves. The components, each weighing 16 tonnes, were lifted by crane into the interior of the dam and then installed.
The annular piston valves are the fittings for controlling the dam. They regulate how much water is released to the lower reaches via the two bottom outlet pipes. This is relevant during floods, for example, but also to increase the low water level during drought. The bottom outlets each have a diameter of two metres. They are installed inside the dam in the so-called slide gate house.
The Pirk dam was built between 1935 and 1939. Up to now, the annular piston valves were largely still in their original condition. They have been repaired in recent years. However, age-related wear and tear had increasingly limited the operability of the valves.
Functionality restored
The new construction restored unrestricted functionality. A steel-welded annular piston valve with a diameter of two metres was installed in each of the two basic discharge pipes. The two large valves are custom-made. In addition, the water technical equipment was extended and extensive corrosion protection work was carried out.
The construction work was carried out while the dam was still in operation. For this reason, there were two construction phases, in each of which only one bottom outlet was rehabilitated. The dam also received a new access to the control gallery on the left slope. The total costs amount to about 3.9 million euros and are financed by the Free State of Saxony.
The first large armature weighing 16 tonnes was delivered and unloaded in one piece in November 2021. At the same time, the old valve was removed and transported away. This was followed by various repair and preparatory works for the installation of the new fitting.
