Patent attributes
Mounted on an upper surface of a container main body are a base of a water level indicator detecting a remaining amount of liquid reducing agent, a base of a densitometer detecting concentration of liquid reducing agent, a heat exchanger surrounding detectors of the water level indicator and the densitometer, and circulating engine coolant for heat exchange between liquid reducing agent and engine coolant, and a suction tube for sucking liquid reducing agent from a position adjacent to the bottom of container main body and between water level indicator and densitometer. A box-shaped protector surrounds the water level indicator, densitometer and suction tube which are located in a region adjacent to a lower portion of the heat exchanger. Heat from the heat exchanger is trapped in the protector to generate convection in that region, thereby unfreezing frozen liquid reducing agent around the water level indicator, densitometer and suction tube.
