Secondary seal
In floating tank roofs, due to various irregularities which are often found on the inside surfaces of tank walls, it is often difficult to maintain a seal with the tank wall. One of the problems encountered is that projections on the tank wall, such as, for example, welding beads, may, upon downward movement of the tank roof, engage the secondary seal and cause it to be disengaged from the guide shoes so that the seal no longer performs satisfactorily. Difficulties previously encountered are solved by providing an adapter means which positions the secondary seal so as to reduce the likelihood of engagement by projections from the tank wall and further provides retention means for resisting disengagement of the secondary seal. The combination provided insures retention of the secondary seal in engagement with the guide shoes of the primary seal under all conditions of operation. (4 claims)
- Assignee:
- Helmerich and Payne Inc.
- Patent Number(s):
- US 3422981
- OSTI ID:
- 5650059
- Country of Publication:
- United States
- Language:
- English
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