Patent Application
20070286018
Some embodiments of the present invention provide a mixing impeller drive system and method that provides a convenient, economical and rapid installation and removal of the drive system from the remainder of the mixer assembly. In one example embodiment, a bayonet type mounting arrangement is provided. Preferred embodiments will now be described with reference to the drawing figures, in which like reference numerals refer to like parts throughout.
The lower end 20 of the lower shell portion 14 extends downwardly as shown. The inner diameter surface of the lower shell portion 14 has an inner diameter sized to fit over a diameter of a cylindrical side surface 22 of the bearing housing 24. The bearing housing 24 supports an impeller shaft 26 as shown. The bearing housing 24 also has a lower end 28 that is sized to be mounted to an opening of a mixing vessel (not shown) in
The horizontal portion of the L-shaped slot 34 may be slightly angled or tapered so that it tends to cam against the threaded surface of the wing screw 36, forcing the lower shell portion 14 downward and further contributing to the bottom end 20 bottoming out on the shoulder 38. Once the lower end 20 is fully bottomed out on the shoulder 38, the wing screw 36 is tightened, thereby securing the entire assembly in place.
In the preferred embodiment illustrated, two opposed wing screws 36 are provided, but any other number may be used. Typically to or more wing screws 36 will be provided, but, for example, if close alignment is not required, or if other alignment features are used, some embodiments may have solely one wing screw.
Also, although a wing screw is illustrated, it will be appreciated that any other type of tightenable fastener, such as, for example, an allen head screw, Philips head screw, a machine head screw, or other like fasteners can be used to engage the L-shaped slot 34 and also to tighten against it. Also, in some embodiments, instead of a removable screw, a fixed radially protruding post may be provided which interacts with the L-shaped slot 34. Further, although an L-shaped slot is depicted having a generally vertical axial leg portion meeting at substantially right angles with a generally horizontal portion (which might be slightly tapered or tilted to provide a tightening effect) it will be appreciated that other shapes of keyways can be utilized in place of the L-shaped slot 34, and in particular, may be shaped and designed to operatively correspond with the fixed post or removable fastener 36 being used.
Also a combination of one or more screws or posts may be used. Also, the slots and screws/posts can be reversed so the slots are on the surface 22 and the screws/posts extend inward from the lower shell portion 14. Besides slots and screws/posts, any other interlocking mechanical connection can be employed, including threads or mating keyways. Generally, all of these mechanical attachments include various bayonet mounts.
Some embodiments according to the present invention can be utilized wherever it is desirable to have a quick release drive system for a mixer including, for example, magnetically driven mixers. They may also be usable in other applications other than magnetic mixers, for example, where instead of a magnetic canister and inner and outer magnetic rotors, a simple splined or other axial end-to-end shaft connection may be implemented.
However, one particularly advantageous use of the above-described embodiment is in the context of sanitary and/or clean-in-place magnetically driven mixers. In some embodiments, sanitary and/or clean-in-place magnetically driven mixers may be completely sealed and may even be disposable. Such mixers may be completely sealed at the time of manufacture, and once filled and used for a mixing cycle and then emptied, some sealed magnetic mixers vessels may be disposable.
In these systems, a particularly advantageous manufacturing process can be implemented wherein a manufacturing facility may utilize one or a limited number of drive systems which is less than a number of vessels that are used in the manufacturing facility. That is, the drive systems can be quickly changed from one vessel to another.
Also, in the case of disposable vessels, or vessels that are taken off site for cleaning or refurbishment, a useful arrangement can be obtained where (1) the vessels are delivered without a drive system, (2) a drive system which is already at the facility is quickly mounted onto the vessel, (3) the mixing cycle is performed, and then (4) the drive system can be quickly removed. In another embodiment of the invention, standard sizes of canisters and bearing housing can be developed over a range of different standard sizes, and corresponding standard size lower shells 14 can also be designed, so that a system is provided having a number of different user selectable corresponding standard sizes.
In the illustrated embodiment, the lower end 20 of the lower shell portion 14 provides a positive bottoming out stop facing against the shoulder 38. This provides an advantage of these embodiments, wherein a positive axial placement as well as axial alignment is provided by the interface of these two surfaces. This facilitates alignment of the inner and outer magnetic rotors and proper drive operation. However, in other embodiments, other alignment contact surfaces may be provided and besides being a flat bottom end 20.
The many features and advantages of the invention are apparent from the detailed specification, and thus, it is intended by the appended claims to cover all such features and advantages of the invention which fall within the true spirit and scope of the invention. Further, since numerous modifications and variations will readily occur to those skilled in the art, it is not desired to limit the invention to the exact construction and operation illustrated and described, and accordingly, all suitable modifications and equivalents may be resorted to, falling within the scope of the invention.
