When a fire occurs, the heat of the fire expands the liquid in the Quartzoid bulb until, as its moment of operation; the bulb shatters into small pieces. The whole valve assembly is then thrown clear off the sprinkler yoke to leave a clear orifice discharging water on the deflector, which distributes it evenly over the fire area.

When a fire occurs, the heat of the fire expands the liquid in the Quartzoid bulb until, as its moment of operation; the bulb shatters into small pieces. The whole valve assembly is then thrown clear off the sprinkler yoke to leave a clear orifice discharging water on the deflector, which distributes it evenly over the fire area.