AVK free flow hydrant for quick relief of water supply line

Replacement of a DN500 gate valve

The water supply line comprises a total length of five kilometers and as a first step of the refurbishment, a DN500 gate valve was replaced. Due to a long lifetime it had stopped functioning properly and a new gate valve with by-pass was mounted instead. To replace the old gate valve, the old ductile iron pipe was cut and disconnected from the valve.

The importance of saving time

Maintenance and refurbishment of such a major supply line always implies certain obstacles to the public and to road traffic and it has in general high costs. Thus, it is of great importance that these activities are carried out as time-saving as possible.

Free flow hydrant for drainage

A supply line of such a large dimension always remains half-filled after a shut-off, and drainage of the line in the usual way using a standard hydrant takes a lot of time. An AVK free flow hydrant was mounted via a T-piece that was flanged directly to the gate valve and due to the full bore of the hydrant, a self-priming pump could easily be inserted to help drain the line. By means of this self-priming pump together with the free flow hydrant, an additional volume of 36 m³/h could be drained from the line.

After the successful installation, Stadtwerke Herford have planned to use additional AVK free flow hydrants and gate valves for other parts of the supply line as well.