Abstract: A spraying device that sprays of a mixture of fluids is monitored to determine whether it is functioning properly. The spraying device has inlets for at least two fluids, such as water and air, and a mixing chamber in which the fluids are mixed. A mixture pressure sensor is mounted on the spraying device to detect the pressure of the mixture. The input pressures of the fluids entering the spraying device are also measured. A formula having left- and right-hand sides is provided for describing a relationship between the actual mixture pressure and the actual pressures of the first and second fluids. Based on the relationship provided by the formula, a comparison process is used to determine whether the spraying device is functioning properly.

Abstract: A spraying device that sprays of a mixture of fluids is monitored to determine whether it is functioning properly. The spraying device has inlets for at least two fluids, such as water and air, and a mixing chamber in which the fluids are mixed. A mixture pressure sensor is mounted on the spraying device to detect the pressure of the mixture. The input pressures of the fluids entering the spraying device are also measured. The measured input pressures of the fluids are used to calculate a predicted mixture pressure based on an empirical formula, which has parameters that can be derived when the spraying device is installed in its operating position. The calculated pressure value and the measured actual mixture pressure are then used in a comparison process to determine whether or not the spraying device is functioning properly.