| 摘要 |
The invention relates to a concrete mixer truck having a mixer drum adapted to be rotatably driven, a water container, a water conduit leading from the container to the drum, and a water pump. An object of the invention is to prevent the quality of a properly composed mixture contained in the drum from being deteriorated by unintentional addition thereto of water from the water container. This is accomplished by the use of a measuring device determining the drive torque for the mixer drum and a valve disposed in the water conduit and controlled by said measuring device in such a manner that the water conduit is closed when the drive torque exceeds a selectively adjustable rated value corresponding at least to the drive torque required for the empty drum. For special conditions of for instance climatic nature requiring the addition of a limited amount of water prior to use, a further development of the invention provides the employ of a water supply opening switch adapted to be opened once during each valve-closure phase for admitting a limited and preselected amount of water.
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