The present invention relates generally to apparatus and methods for supporting steady bearings, which are used to support impeller shafts mounted in a variety of reactors, vessels and mixing apparatus. Steady bearings for shafts in such vessels are in wide use in the chemical, petroleum, pharmaceutical, cosmetic, food preparation and other industries. More particularly, the present invention relates to a flexibly supported steady bearing to support impeller shafts mounted in a variety of reactors, vessels and mixing apparatus.
When in operation impeller shafts are subject to a number of forces that act to damage and possibly lead to failure of the impeller shaft. A mixer shaft driving an impeller in a vessel can undergo substantial dynamic bending distortion during mixing operation. This deflection can cause permanent damage or distortion and even complete failure of the impeller shaft during operation. It is also known that impeller shafts, especially longer shafts are prone to lateral displacement while in operation, due to the force of loads in the mixing vessel.
It is known to provide one or more intermediate steady bearings along an impeller shaft to control dynamic bending distortion of the shaft. In addition, such assemblies provide lateral stability to the impeller shaft during operation. Even when an intermediate steady bearing is used to support an impeller shaft as indicated above, the shaft can still be prone to deflection during operation. In rigid bearing designs it may not be possible for the bearing to track the angular changes in the contact surface of the impeller shaft when the shaft is subject elastic deflection during operation. This leads to hard contact of the impeller shaft at the two ends of the bearing assembly. Hard contact resulting from this deficiency in rigid bearing designs can lead to excessive and uneven wear of bearing components, e.g., in an hourglass pattern.
Accordingly, it is desirable to provide a flexible steady bearing support assembly that allows the bearing components to track the contact surface of the impeller shaft when the impeller is in operation.
It is therefore a feature and advantage of the present invention to provide an improved flexible support for a steady bearing in rotational contact with the surface of a shaft, which allows the bearing and housing to track the contact surface of an impeller shaft, even when the shaft is subject to significant elastic angular deflection during operation.
The above and other features and advantages are achieved through the use of a novel flexible support for a steady bearing using a flexible disc pack.
In accordance with a general embodiment of the present invention, at least one flexible disc pack is provided, which is comprised of a plurality of thin, flexible disc elements in a stacked arrangement. The radial dimensions of the individual disc elements and the thickness and number of disc elements can vary dependent on the dimensions of the shaft and bearing elements with which the invention is to be used.
Accordingly, in one aspect of the invention, therefore, several disc elements are assembled in a stacked arrangement to produce a xe2x80x9cdisc packxe2x80x9d, which is incorporated into the new flexible bearing support design. In some embodiments, a disc pack is comprised of three individual disc elements, but may contain more based on the requirements of the bearing design. The disc pack can be mounted to a rigid support ring, which acts as a means for supporting the bearing on the impeller shaft when completely assembled. The support ring can be supported by an assembly of three or more struts.
In another aspect of the current invention, once the disc pack is securely mounted to the rigid support ring, the bearing housing and other bearing elements are mounted to the disc pack, such that the bearing housing and other bearing elements are capable of significant deflection around the vertical axis of the impeller shaft.
There has thus been outlined, rather broadly, the more important features of the invention in order that the detailed description thereof that follows may be better understood, and in order that the present contribution to the art may be better appreciated. There are, of course, additional features of the invention that will be described below and which will form the subject matter of the claims appended hereto.
In this respect, before explaining at least one embodiment of the invention in detail, it is to be understood that the invention is not limited in its application to the details of construction and to the arrangements of the components set forth in the following description or illustrated in the drawings. The invention is capable of other embodiments and of being practiced and carried out in various ways. Also, it is to be understood that the phraseology and terminology employed herein, as well as the abstract included below, are for the purpose of description and should not be regarded as limiting.
As such, those skilled in the art will appreciate that the conception upon which this disclosure is based may readily be utilized as a basis for the designing of other structures, methods and systems for carrying out the several purposes of the present invention. It is important, therefore, that the claims be regarded as including such equivalent constructions insofar as they do not depart from the spirit and scope of the present invention.