ADDITIVE MEASURING AND INJECTION DEVICE OF MIXER CAR

PURPOSE:To keep the slump value of unhardened concrete at a proper value, by utilizing a washing motor and an electric pump normally equipped in a mixer car and sensing the pressure of a driving circuit by the pump and controlling the quantity of an additive to be added. CONSTITUTION:In a concrete mixer car on which a mixer drum is placed to allow free rotation and the mixer drum is driven by a hydraulic motor, the pressure 5 of the driving circuit of the hydraulic motor C is detected by a device B. At the same time, the time proportional to the detected pressure is set by a timer C. A motor D is driven by an output of the timer C, and an additive injecting means E consiting of an additive tank 8, a spouting nozzle 9, pipings 10, 11, etc. injects the additive to the drum through a pump 2 driven by the motor D. A changeover valve 12 is changed over to use the additive injecting pump 2 for a washing water supplying means A of the mixer drum. Consequently, the slump value of unhardened concrete can be maintained at a proper value at all times.