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Xiamen C4400 Insulating Spacer
QS Gasket: Xiamen C4400 Insulating Spacer
Name: Xiamen C4400 Insulating Spacer
Standard: ASME B16.5
Material: Klingersil C4400
Max Temperature: 400℃
Size: 8 Inch
Pressure: 150LB
Complete Set: with G10 Sleeve and Washers and ZPS
Compound: with Aramid Fiber Reinforced with a Nitrile Binder
Standard: ASME B16.5
Material: Klingersil C4400
Max Temperature: 400℃
Size: 8 Inch
Pressure: 150LB
Complete Set: with G10 Sleeve and Washers and ZPS
Compound: with Aramid Fiber Reinforced with a Nitrile Binder
Quantity
C4400 Insulating Spacer is purpose-built for high-voltage electrical flange isolation. It is machined from Klingersil C-4400 sheet, an aramid-fibre / nitrile-rubber composite rated to 400 °C, and is supplied as an ASME B16.5 8″ 150 lb kit. Each set contains a G10 insulating sleeve, insulating washers and ZPS steel hardware, so one installation simultaneously delivers sealing, electrical isolation and corrosion protection—an energy-safe choice for petrochemical plants, offshore platforms and LNG lines.
How many times can a gasket be re-used?
Whether a joint can “clock back in” depends on material, permanent set and service conditions. The quick-re-use ledger below lets field engineers judge at a glance; the C4400 Insulating Spacer case is pulled out separately.
Whether a joint can “clock back in” depends on material, permanent set and service conditions. The quick-re-use ledger below lets field engineers judge at a glance; the C4400 Insulating Spacer case is pulled out separately.
1. Flat or serrated metal gaskets
304, copper or aluminium deform elastically but recover almost no thickness. Refinery rules are explicit: serrated metal gaskets ≥ DN 150 are scrapped on removal; < DN 50 units that show no imprint or bow may be re-installed once only, provided all nicks are removed with 120-grit paper and thickness re-checked—scrap if loss > 3 %.
304, copper or aluminium deform elastically but recover almost no thickness. Refinery rules are explicit: serrated metal gaskets ≥ DN 150 are scrapped on removal; < DN 50 units that show no imprint or bow may be re-installed once only, provided all nicks are removed with 120-grit paper and thickness re-checked—scrap if loss > 3 %.
2. Spring lock washers
They stay tight by “open” spring force. One removal closes the gap angle 5–8°; by the third fit the washer has lost its compensation. Wind-tower data for M20 washers show 18 % preload loss at the third use, so critical joints are “one life only”; non-critical static brackets may go to two cycles.
They stay tight by “open” spring force. One removal closes the gap angle 5–8°; by the third fit the washer has lost its compensation. Wind-tower data for M20 washers show 18 % preload loss at the third use, so critical joints are “one life only”; non-critical static brackets may go to two cycles.
3. Rubber / compressed-fibre sheets
Once the polymer is compression-set, recovery is < 10 %. API 570 visual rule: bright imprint or edge lift means immediate scrap; if surfaces look intact you may refit once, but downgrade the joint one pressure/temperature class.
Once the polymer is compression-set, recovery is < 10 %. API 570 visual rule: bright imprint or edge lift means immediate scrap; if surfaces look intact you may refit once, but downgrade the joint one pressure/temperature class.
4. Graphite composite gaskets
Flexible graphite bonded to tanged metal core gives ~30 % recovery. Hydro-cracker logs show leak rate rising from 0.1 to 0.8 mg s⁻¹ m⁻¹ after four cycles; vendor manuals therefore allow ≤ 5 re-uses, checking each time for graphite delamination or flaking.
Flexible graphite bonded to tanged metal core gives ~30 % recovery. Hydro-cracker logs show leak rate rising from 0.1 to 0.8 mg s⁻¹ m⁻¹ after four cycles; vendor manuals therefore allow ≤ 5 re-uses, checking each time for graphite delamination or flaking.
5. Double-wedge lock washers (Nord-Lock)
Two cams slide to lock; tooth height is only 0.2 mm. Factory tests show ≤ 5 re-uses with < 5 % preload loss if lubricated and rust-free; tooth-tip plasticity starts at the sixth cycle—mandatory scrap.
Two cams slide to lock; tooth height is only 0.2 mm. Factory tests show ≤ 5 re-uses with < 5 % preload loss if lubricated and rust-free; tooth-tip plasticity starts at the sixth cycle—mandatory scrap.
6. Fibre-reinforced sheet gaskets (e.g. Klingersil C4400 Insulating Spacer)
Aramid-nitrile fibres break during compression. For valve static duties the plant norm is “remove—replace”. If spares are unavailable during an emergency repair one re-installation is allowed at 80 % rated pressure with a 24 h re-torque. Note: when C4400 Insulating Spacer is acting as an electrical isolator, any surface scratch lowers dielectric strength; before re-use check insulation resistance with a 500 V megger—scrap if < 500 MΩ.
Aramid-nitrile fibres break during compression. For valve static duties the plant norm is “remove—replace”. If spares are unavailable during an emergency repair one re-installation is allowed at 80 % rated pressure with a 24 h re-torque. Note: when C4400 Insulating Spacer is acting as an electrical isolator, any surface scratch lowers dielectric strength; before re-use check insulation resistance with a 500 V megger—scrap if < 500 MΩ.
Field “three-look” rule
① Look at imprint—scrap if any continuous or shiny mark > 30 % of gasket width.
② Look at thickness—micrometer check at four points, scrap if spread > 0.05 mm.
③ Look at recovery—press with thumb 10 s, scrap if rebound < 50 %.
① Look at imprint—scrap if any continuous or shiny mark > 30 % of gasket width.
② Look at thickness—micrometer check at four points, scrap if spread > 0.05 mm.
③ Look at recovery—press with thumb 10 s, scrap if rebound < 50 %.
For C4400 Insulating Spacer add a fourth look—look at insulation: surface blistering or water-marked yellowing means scrap.
Bottom line: metal gaskets “once is best”, spring washers “two and stop”, soft gaskets “if in doubt, change”; for isolating spacers such as C4400 Insulating Spacer the rule is “throw away rather than save”. Unless you have quantified test data, re-use = risk—the most economical way to long, safe plant runs.
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