This invention relates to seals and more particularly to those employed to seal an opening in a wall through which a shaft or other movable element of a machine extends. It has long been a problem with machinery to prevent the escape fluid under pressure around an element projecting through a casing wall, particularly when the element is movable relative to the wall, like a rotating shaft. In this instance it is proposed to provide a first seal having a primary sealing face and another or secondary seal with one or more sealing faces, all the seals sealing axially. Heretofore, seals provided for use in locations such as the seal of this invention have had a combination of primary and secondary seals, the latter sealing radially which required larger size seals and a greater number of elements. In addition, the previously provided seals were unsatisfactory in that they wore out quicker and leaked excessively.
The seal of the present invention relates to the types of seals exemplified by the following U.S. Pat. Nos.:
2,422,007 to Gilbert PA1 2,736,579 to Dickinson PA1 3,025,069 to Harker PA1 3,169,024 to Johnson et al PA1 3,592,479 to Andresen