The present invention relates to a new and improved construction of mixer arrangement and, in particular, relates to a vat or bucket mixer equipped with a mechanical drive arrangement, especially for the commingling or mixing together of liquid- and powder components, for instance when producing printing inks or the like, and which mixer is of the type comprising a rotatable mixing tool extending to the region of the inner wall of the vat and a toothed disk driven by a shaft, this toothed disk constituting a so-called dissolver disk.
In order to mix ttogether liquid- and powder components there are placed upon the mixer, among other things, the following specific requirements:
(A) Disintegration or tearing apart of the agglomerates;
(B) Optimum dispersion of the constituents; and
(C) Good wetting of the individual pigments.
The properties of the different components should not be destroyed, something which oftentimes is a problem in the case of products which are difficult to work with, such as for instance heat-sensitive products, viscous pastes or thixotropic products.
Moreover, the working operations should be accomplished in an environmentally safe manner, i.e. there should be developed as little dust as possible.
The heretofore known previously described mixers possess two separate drive units. Consequently, it is possible to initially carry out the pre-mixing or starting mixing operation at a relatively low rotational speed with the aid of the mixing tool, so that the power requirements are maintained small and also the formation of dust is low.
After the pre-mixing there is connected the dissolver disk by means of the separate motor in order to disintegrate the agglomerates and to achieve optimum dispersion and use of the powder components. The pre-mixing phase or starting mixing phase, lasts only about five minutes, during which time there is only in operation the mixing tool, and the second phase, during which time there are in operation the mixing tool and the dissolver disk depending upon the strived for quality of the product, lasts up to one hour and more.
By separating the drive for the mixing tool and the dissolver disk it is possible to easily obtain variations in the rotational speed. The determination of the power requirements must be carried out individually both for the mixing tool as well as for the dissolver disk, yet in both instances is difficult. Since it must be presupposed that both demand increased power requirements, it is necessary to design both motors so as to also have the corresponding safety factor, resulting in relatively large structural requirements, and only during part of the fields of application are there in fact realized the advantages.