The hydropower fuse performs two functions:
- A user operated isolating valve, and
- A hydraulic safety fuse.
Hydraulic equipment is powered by the flow of a fluid through it. This is achieved by connecting it to a source of flow (e.g. a pump) with a hose or pipe. It is necessary to isolate (shut off) the supply line & equipment when connecting or disconnecting a hose or pipe. A fuse can be used to supply or shut off flow.
- The fuse poppet reacts to abnormally high flow conditions (such as caused by a hose or pipe failure) and rapidly closes to reduce the flow to a safe volume. This prevents and minimizes the danger of water spray and hose whip. Hose whip intensity depends on how much flow can be supplied (by the pump) and the size of the hose.
- The fuse consists of a Poppet Body, Isolating Valve with handle, Fuse Body, and Fuse Element. The Poppet Body houses the Isolating Valve, and comprises an NW 32 M staple-lock inlet. The Fuse Body houses the Fuse Element, and comprises an NW staple-lock outlet.
- The fuse element is normally open. Flow passing through the fuse drags the fuse element towards a closed position (see top view in the figure below). A spring keeps the fuse element open under normal working flow-rates.
- Under abnormally high flow conditions (such as caused by a hose or pipe failure) the flow will overcome the spring and close the fuse element (trip the fuse). The supply pressure keeps the fuse tripped (fuse element closed). A small leakage flow allows the downstream hose to be refilled safely and the fuse poppet to release once the fault is rectified (see bottom view in the figure below).