Underground fire hydrants

AVK series 35 underground fire hydrants

Automatic drainage

The 8 mm drainage hole is automatically closed over the entire valve lift, so that no pressurised water can escape. This means that the drainage hole is closed before the pressurised water is able to flow into the hydrant, and no pressurised water can escape. The patented valve disc in the single shut-off underground fire hydrant is asymmetrically shaped to speed up water withdrawal and emptying. This also reduces the number of turns from closed position to stop.

Corrosion protection

Our double shut-off underground fire hydrants are provided with threaded holes for all threaded connections. This refers to the connections between the claw, the end cap and the upper barrel as well as between the upper barrel and the ball chamber. There are no open thread pitches, which avoids contamination and corrosion. Furthermore,  the main seal ring for the ball shut-off is vulcanized with EPDM for optimisation of the corrosion protection.

Optimisations

In order to facilitate installation and ensure the best possible ergonomic handling, the fire hydrants have been weight optimised. The valve cone is completely vulcanized with polyurethane (PUR), and the high quality of this elastomer ensures an optimal sealing due to its unique memory effect. The double seal of the stem consists of a scraper and a brass bush as a plain bearing with three O-rings.