Many industries transport, store, mix, process and/or discharge fluids from commercial bulk containers made of plastic or metal, commonly known in the trade as “tote boxes”, “bulk containers”, or “intermediate bulk containers” (all herein referred to as “containers”). It is often desirable, and in some cases required, that the fluids stored in such containers be agitated, mixed or blended between the time they are loaded into the containers and the time they are discharged therefrom. To affect the desired mixing, according to the prior art, it was necessary to open the container and insert a mixing unit with impeller blades. There are, however, several drawbacks to this approach.
A first disadvantage of mixing assemblies used in the art is that as a plurality of containers are usually stored in close proximity, it may be difficult to access the selected container to remove the cover of the access opening or port and to insert the mixing unit. Even if the cover of the opening is readily accessible, it may be difficult to remove the cover, particularly if the material in the container is highly volatile and the lid or port had been sealed to retain vapors.
Furthermore, the diameter of the access opening through which the mixing unit is inserted must be of sufficient diameter to allow the insertion of the impeller blades. In addition, if the container is substantially full, the mixing assembly has to be operated with considerable care so as not to splash, or otherwise spill, the contents of the container. This often requires operating the mixing assembly at speeds and power settings insufficient to properly agitate or mix the contents of the container.
Mixing units, including the drives and impellers (which are usually a single unit), are usually used with multiple containers and require extensive cleaning each time they are moved from one container to another. At present the containers and mixing units are cleaned after each use, resulting in high costs (both environmentally and in equipment/manpower). For many fluids used in the paint, chemical, and pharmaceutical industries the slightest contaminant left from ineffective cleaning may ruin the fluids in the container. Further substantial costs are also incurred through the expense of using and disposing of cleaning agents such as solvents. Finally, there is a manpower cost in the amount of time required to open, mix, close and seal each container.
Another mount for mixing units in the prior art is a bridge mounting that supports the mixing unit above the vessel neck. These mounts also do not seal the container completely thereby allowing contaminants to enter the container.
Another solution in the prior art is the use of fully enclosed mixing units within stainless steel bulk containers. Unlike plastic containers, steel containers require extensive and often imperfect cleaning after each use which may contaminate the container contents. The use and disposal of powerful solvents and cleaning agents also create a large cost.
Another solution in the prior art is to support mixers by the use of expensive threaded metal lids for mounting the mixer. These lids rely on the threads of the neck and collar of the container to support the loads applied during mixing and often result in cracking of the bulk container and failure of the mount.
Yet another method of mixer support is a clamping device positioned around the neck of the container. This may cause difficulties as the clamping shoe inside the housing may collapse the neck of the container. Alternatively, this mount may also rotate on the neck of the container.
What is needed is an assembly that seals the container, and does not require any additional support means other than the container itself. Additionally what is needed is a power module that can be detachably secured to the container and mixing assembly.