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LineBacker® Sealing (Non-Isolating) Gaskets
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LineBacker® sealing gaskets utilize a patented rectangular sealing element, referred to as a “quad” ring, in combination
with a unique groove design to effectively seal flanges of all types. With the unique “quad” ring design, elastic
memory is provided for elastomers not normally associated with this characteristic. Materials such as AFLAS, TFE (Teflon)
and KALREZ may therefore be used as sealing elements which dramatically increases the options available for matching gasket
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materials to service and environmental conditions. This greater variety of materials also provides excellent temperature and
chemical range compatibility. LineBacker® sealing gaskets are self energizing with theoretical near zero “m” and “y” factors
resulting in effecting a positive seal without excessive bolt loads required with flat gaskets.
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Before Tightening
The flange faces come into contact with the sealing elements, which extend slightly above the surface of the
retainer. As the flange is tightened the sealing elements are compressed and move sideways into the inclined
portion of the groove, developing a high unit pressure against the flange faces.
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After Tightening
The flange faces have come into firm contact with the retainer, thus encapsulating the sealing elements within grooves.
At the same time, the unique LineBacker seal configuration provides elastic memory for elastomers not normally associated
with this characteristic - resulting in a simple flat gasket with extremely high loading and self energizing characteristics
without adverse cold flow problems.
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TYPE E GASKET
The gasket retainer extends out to the O.D. of the flange. Holes are cut in a type "E" gasket at the bolt circle to accommodate
threaded studs or bolts.
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TYPE F GASKET
The gasket retainer extends out to the I.D. of the bolt circle.
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- Eliminates Flange Leaks.
- Guards against blowouts.
- Protects against fire and hostile environments.
- Usable with any type of flange.
- Matches gasket materials to service conditions.
- Lowest possible clamp and compressive load.
- Increases gasket life.
- Insulating version is both a positive seal and a superior insulator.
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Sizes
- All standard ANSI and API flange sizes from 1/2" and above.
- Custom odd sizes and shapes.
Pressure Ratings
- All ANSI and API rated flanges.
- Pressures from hard vacuum to 50,000 psi and higher.
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Metallic Gasket Retainer and Seal Element Options |
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| Metallic
Retainer
Materials |
| Sealing
Elements | |
Aluminum | Buna-N (Nitrile) |
Brass | Buna-S |
Carpenter 20 | Butyl |
Carbon Steel | EPDM |
Cast Iron | Hypolon |
Clad Steel Materials | Kel-F |
Copper | Natural Rubbers |
Ductile Iron | Neoprene |
Hastelloy B | Nylon |
Hastelloy C | Polyimide |
Hastelloy X | Polyurethane |
Inconel X | Silicone Rubber |
Monel | Teflon® |
Nickel 200 | Vinyl |
Soft Iron | Viton® |
Stainless Steel | |
Tantalum | |
Tin | |
Titanium | |
Vanadium | |
®DuPont
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All products are warranted against failure caused by manufacturing defects for a period of one year. Any product found to be
so defective and returned within one year from date of shipment will be replaced without charge. The above warranty is made in
lieu of, and we disclaim, any and all other warranties, | |
expressed or implied, including the warranties of merchantability and
fitness for a particular purpose, and buyer agrees to accept the products without any such warranties. We hereby disclaim any
obligation or liability for consequential damages, labor costs or any other claims or liabilities of any kind whatsoever. |
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- Open packaging to inspect and determine that components are as specified. Check the gasket I.D.
It should be no greater than the flange I.D.
- Flanges shall be free of pits, gouges, rust, debris, oil and grease. Surface finish shall be no greater
than 250 RMS. Refinish flange faces if corrective measures do not meet the foregoing. Check flange and bolt hole
spot facings for burrs, etc… and clear from facings.
- Check bolts and nuts and clean. Apply non-conductive lubricant to all threads and flange side of nuts.
- Align flanges so they are concentric and parallel and install gasket carefully. USE NO LUBRICANT, GREASE OR
ADHESIVES ON EITHER THE GASKET OR FLANGE FACES, Guard against damaging sealing element.
- Line up bolt holes with non-tapered drift pins using three at 120° degrees separation (particularly large flanges),
or at least two at 180° degrees separation.
- Insert studs,
nuts and washers, placing lubricated face of nut next to steel washer (this will help to reduce galling of the insulating
washer on flange, should the whole bolt assembly rotate). Galling: If serious galling of insulating washers persists,
replace with high strength washers. (minimum 50K psi or greater).
- Initially cross-tighten bolts until flange to gasket contact has been made.
- Check for a flange segment that may show a gap or separation between gasket and flanges, using flashlight,
calipers, or feeler gauge. If one exists, the flanges are not parallel.
- Directly 180° degrees opposite widest part of indicated gap, loosen nuts, even if only finger tight, one or more turns.
Return to segment with gap and tighten until both flanges are in contact with gasket retainer. This procedure is necessary
to prevent restriction of flange rotation over the fulcrum formed by the outer edge of the two raised faces at points in
contact with gasket retainer. The restriction will cause exceptionally high flange to gasket clamp loading at this point,
with possible damage to gasket retainer, PLUS diverting necessary clamp loading bolt torque energy to correcting
alignment on the opposite segment.
- Re-tighten loosened nuts and proceed with torqueing of the bolts according to PSI diagram, to 10-15% of specified
torque. Remove drift pins and replace with bolts, nuts and washers, tightened to the same values as others in place.
- Repeat torque sequence, increasing to 50% of balance.
- Repeat tightening to final torque.
- Optional – it is always a good policy to go completely around flange checking bolt to bolt for proper torque, particularly
on large diameter piping systems.
- All the above should be done with torque wrenches (mechanical and hydraulic) or with a stud tension measuring device.
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Always wear appropriate safety equipment!
Important: Check gasket for flange type on which to be used (ie). Slip or weld-neck etc…If in doubt do not install, consult supplier or PSI.
To provide even sealing pressure on a flange gasket it is recommended that the bolts be “snugged” up in the sequence shown on
chart until the flange faces are in contact with the gasket. After the flange faces are in contact with the gasket firmly
tighten the bolts in the same sequence. Note: Although this diagram shows 24 bolts, the same basic procedure should be used
with flanges having more or less bolts. When installing gaskets made of compressible dielectric material and tightened cold;
“hot flow” of the gasket material may occur under operating conditions, resulting in loss of bolt pressure. It is advisable
therefore, to re-tighten bolts after operating temperature has been reached – preferably at zero line pressure and ambient
temperature. Under no circumstances should the system be allowed to return to operating
temperature after the initial cycling to ambient temperature without checking and re-tightening bolts where needed.
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Suggested torque values for PSI sealing gaskets.
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To order LineBacker® Sealing/Isoulating Gaskets please indicate the following:
- Quantity
- Nominal Pipe Size
- Pressure Rating
- Gasket Type: E or F
- Gasket Style: LineBacker®
- Retainer Material
- Sealing Element
- Weld neck or slip-on application
- Note all special requirements.
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Contact your local distributor or Pipeline Seal & Insulator, Inc.
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Distributor Locator
Contact PSI
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Sealing Gaskets
A 12 page booklet that includes all PSI Sealing Gaskets including specifications, material compatibility charts and
features.
PDF File Size = 1,014KB.
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Flange Isolation Kits.
A 12 page booklet that includes all PSI flange isolation kits.
PDF File Size = 532KB.
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