Internal Floating Roof
Internal floating roof sealing
A range of primary and secondary sealing systems designed to maintain effective sealing around the tank rim and further reduce vapour emissions.
Primary seal
Liquid-mounted Foam Log Seal
Liquid-mounted foam log keeps the rim vapour space to an absolute minimum for the best emission control.
A primary rim seal for internal floating roofs in which a flexible foam-filled log is mounted so that its lower part contacts the stored liquid. The closed-cell foam core is wrapped in a hydrocarbon-resistant fabric envelope and pressed continuously against the tank shell by the roof rim. Being liquid-mounted, the seal stays wetted by the product, which keeps the vapour space between the seal and the liquid to a minimum.
Advantage:
1. Liquid-mounted design keeps the rim vapour space to a minimum - the most effective primary-seal arrangement for emission control.
2. The flexible foam core accommodates normal tank shell out-of-roundness and roof movement without losing contact.
3. Simple, low-cost construction with no metal shoe or pantograph mechanism to maintain.
4. Light weight reduces seal drag and the load imposed on the floating roof rim.
5. The fabric envelope resists hydrocarbons, UV and ozone and is readily replaceable in service.
6. Designed for a standard rim-gap tolerance of +/-100 mm, so it suits both new and existing riveted or welded tanks.
Mechanical Shoe Seal
Write your text here...Continuous metal-to-shell contact gives the longest life and best abrasion resistance of any primary seal.
A metal-shoe primary seal for internal and external floating roofs. A series of galvanised or stainless-steel shoe plates around the roof rim is pressed against the tank shell by a pantograph (scissor) or counterweight linkage, and the gap between the shoe and the roof rim is closed by a vapour-barrier fabric. The shoe rides up and down with the roof while maintaining continuous metal-to-shell contact. It is the most widely used primary seal on floating roof tanks.
Advantage:
1. Continuous metal contact with the tank shell gives excellent abrasion resistance and the longest life expectancy of any primary seal.
2. Accommodates wide variations in rim space and shell out-of-roundness, including riveted tanks.
3. Uniform pressure distribution across 6 to 9 contact points keeps the shoe in full contact around the whole circumference.
4. Provides roof-centring capability that keeps the floating roof centred in the tank.
5. Available with wax scrapers for waxy crude, and with fabric in PTFE, polyurethane or calcium silicate for 100%-aromatic service.
6. Complies with API 650 and EN 14015; capable of gas-tight (TUV) certification when combined with a suitable secondary seal.
Compression Plate Seal
Overlapping metal plates hold a reliable seal under wind and seismic load, and can reach gas-tight performance.
A rim seal in which overlapping stainless-steel compression plates are pressed against the tank shell by a spring or compression mechanism, while a vapour-barrier fabric closes the gap between the plate ring and the floating roof rim. It is most commonly installed over the primary seal.
Advantage:
1. Continuous mechanical contact with the shell gives reliable sealing under wind, seismic and roof-tilt conditions.
2. The overlapping plate design tolerates shell out-of-roundness and local deformation without losing contact.
3. Metal construction is inherently resistant to UV, ozone and hydrocarbon attack, giving long life with minimal maintenance.
4. Vapour-barrier fabric is available in PTFE, polyurethane or calcium silicate to suit 100%-aromatic products.
5. Complies with API 650; it can also serve as a rain-shield (weather-shield) seal for external floating roofs, and combined with a mechanical-shoe or liquid-mounted primary seal it can achieve gas-tight performance.
Secondary seal
Wiper Seal (Secondary Seal)
Simple, low-cost secondary seal that dramatically cuts rim vapour emissions.
A rim-mounted secondary seal for internal floating roofs. A flexible elastomeric wiper blade is clamped around the roof rim above the primary seal and sweeps against the tank shell as the roof moves, closing the annular space between the top of the primary seal and the roof rim. It is the standard second line of defence against vapour escape at the rim and is normally used together with a primary seal.
Advantage:
1. Dramatically cuts rim vapour emissions when combined with any primary seal.
2. Simple, low-cost and lightweight, with minimal load on the floating roof and no mechanism to maintain.
3. The flexible blade absorbs roof tilting, rim-space variation and shell out-of-roundness.
4. Materials available for 100%-aromatic and other aggressive service.
5. Can be installed and replaced with the tank in service.
6. Complies with API 650 requirements for secondary sealing of internal floating roof tanks.
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Contact (Technical Manager )
zhangtizhe@floattek.cn
+8618114309509
Changzhou, China
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