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A volumetric concrete mixer (also known as volumetric mobile mixer and metered concrete truck) is a truck that contains concrete ingredient materials and water to be mixed on the truck at the job site to make and deliver concrete according to the amount needed.
Contents
The mixer is a mixing device that measures the raw materials using volume rather than weight. The volumetric mixer blends the concrete mixture using an auger or a paddle or a drum device to mix the ingredients with water. The volumetric mixing process starts with a batch metering system that allows the volume of raw materials to be measured prior to entering the mixing chamber. This process can be as simple as using a measured bucket, to highly sophisticated and computerized batch plants that feed the correct volume.
Types
The mixing chamber can vary depending upon the application and the mix design of the concrete.
In an auger type mixer, the material and water travels up the Archimedes' screw. Auger lengths can vary from about 5-feet to 15-feet, and vary in diameter and RPM. This type may be portable, but the length of the auger is a limiting factor.
A paddle mixer blends the concrete mix using a rotational motion and is used to blend finer gravels and sand, as in mortar. The majority of drum mixers are mounted on trailers and are pulled to a job site using a pick-up truck. These drums usually have a mixing capacity of between 1-yard and 1.75 yards (0.76 and 1.34m3) per batch.
A paddle mixer tumbles the mixture in a folding motion using curved fins and paddles. This is the most common type of volumetric mixing. Paddle mixers usually mix in smaller batches directly on the job site.
History
The history of volumetric mixing comes from several directions;