Concrete Mixer Truck
1.Working principle of Concrete Mixer Truck
The concrete mixer truck of gravity-enforced action with the spiralblade shaft
2、hydraulic drive of drum control;
7、spiral blades on the drum body;
8、supports for spiral-blade shaft fastening;
10、hydraulic drive of spiral-blade shaft ;
Universal nature of such concrete mixer truck of gravity-enforced action allows to use it in concrete mix preparation of different purpose considering the needs of the sites under the construction. Such concrete mixer trucks can be efficiently used in the technological complexes when performing by cement gun works by wetmethod. The offered construction of the spiral-blade shaft should ensure liquidation of the zones in the drum being free of outworking by the working part. It may be validated by the research results of the concrete mix particles’ motion path in the workspace of the concrete mixer truck. It is required to build up the concrete mix particles’ motion path when descending from the blades of the rotating drum as well as the blades and spiral turns of the running shaft. The absolute velocity of concrete mix particles descending from the 1. drum blades of the concrete mixer truck:
Capacity to prepare dry and extra dry concrete mixes in the concrete mixer trucks not only high-flow but also of low-slump, dry
and extra dry types of concrete mixes provide for a design development of the working machines and intensification of the mixing working processes of mix ingredients.Concrete mix preparation is the most important scope in the total amount of the construction works. A potential level of concrete features is formed on this stage.
For the time being, it is significant to perform an in-depth study of common factors, bounding concrete properties with its structure and parameters of technology involving contemporary views of physicochemical mechanics, rheology, thermodynamics, colloid chemistry, elasticity theory, etc.
The outputs of these works are essentially of phenomenological nature and may not, as a rule, provide a full qualitative assessment of the prepared concrete mixes features correlation influenced by the machines’ constructive peculiarities, in particular, which are used for their preparation. Thus, in practice it is continued to be guided, first of all, with the general regularities established by an experimental approach. Improving of current and creating of new designs of mixers is one of the main trends among the focal points in theory and practice of high-performance mixing equipment creation.
Low balancing capacity both at macro level and micro level is a major disadvantage of the work of the current concrete mixer trucks.
In order to enhance efficiency of the concrete mixer trucks operations it is required to introduce new approaches into their design, one of which is a cascade operation mode of the machines.
Almost the whole capacity of their body become working during the machines’ cascade operation mode. The design peculiarities of these machines ensure displacements of the concrete mix components during their movement along the composite paths, where free fall is available from above the blades of the machine actuating element, which is typical for gravity mixing method, and then, in the lower body of the mixer upon getting on the blades of running blade shaft the free -falling mixture components are involved in forced mixing
Option shall be considered to create concrete mixer trucks for preparation not only of high-flow but also of low-slump and dry type concrete mixes. With these aims it is offered to transfer operation to the cascade mode being characterised by combination of two principles on concrete mix preparation: gravitational and forced action. Design solution of the concrete mixer truck of gravitational-forced operation with spiral-blade shaft has allowed to liquidate available free places in the drum. The dependencies for calculation and arrangement of mix particles motion in the workspace of the machine drum are provided.