- This seal is similar to the P-FS-01 as both comprise tough, polymer coated envelopes surrounding compressible polyurethane foam; however, in this case the foam is octagonal in cross section.
- The actual size of the foam is calculated from consideration of the nominal rim gap and shell deviations.
- Movement of the foam in a vertical direction is controlled by internal hold-down plates. However, the foam is not fixed to the hold-down plates.
- As with all foam seals a soft sealing pressure is exerted against the tank shell and, if the seal is product mounted, its efficiency is as high as possible as defined in API Chapter 19.
- May be attached to either a vertical or horizontal fixing point.
- As with all foam seals the seal envelope can be subject to damage by sharp points on the tank shell leading to the tank contents coming into contact with the foam blocks causing seal failure. This may also occur if care is not taken when making the final joint in the seal envelope.
- With the exception of waxy crude oil, the Graver foam seal is used throughout the whole range of crudes and refined products.
- The seal can be mounted either in contact with the liquid or above the liquid (vapour mounted).
- The P-FG-01 can be used on rim gaps varying in size from 100mm to 250mm while coping with the commensurate shell deviations throughout.
- The seal can also be designed to suit internal floating pan decks.