What's the disc on the valve that opens the water on the hydrant?
There are many kinds of hydrants, mainly divided into indoor and outdoor two categories.
Outdoor fire hydrant to prevent unauthorized personnel from opening, without hand wheel. A special wrench for fire personnel is required to open. Besides, the water outlet is provided with a fast blocking cover, and can be quickly disassembled when used.
Fire hydrant (fire hydrant) on the tap water on the disc, called hand wheel, usually black, fire hydrant (fire hydrant main body is red).
