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218020209 — SEAT,VALVE

✓ Government record, cited
— · GATE VALVE
PRODUCT OVERVIEW

218020209: SEAT,VALVE.

The SEAT,VALVE is a the manufacturer industrial component. Key specifications include material: PLASTIC POLYTETRAFLUOROETHYLENE SEAT, thread_class: 3A SINGLE THREADED PORTION A, thread_length: 0.752 INCHES NOMINAL SINGLE THREADED PORTION IN, overall_height: 1.375 INCHES NOMINAL IN, hardness_rating: 115.0 ROCKWELL R NOMINAL SEAT, special_features: A/K/A SEAT, LOWER. This part is cataloged in the U.S.

Government catalog under NSN 4820-01-442-0439, indicating validated use in U.S. government and defense logistics supply chains. Available through authorized enterprise resellers and TPM (Third Party Maintenance) channels.

Verify compatibility with your specific system configuration before ordering.

WHERE IT FITS
218020209
NSN: 4820-01-442-0439
FSC: 4820 — Valves, Nonpowered
CAGE: 53711 — NAVAL SEA SYSTEMS COMMAND (USA)
SPECIFICATIONS
materialPLASTIC POLYTETRAFLUOROETHYLENE SEAT
thread_class3A SINGLE THREADED PORTION A
thread_length0.752 INCHES NOMINAL SINGLE THREADED PORTION IN
overall_height1.375 INCHES NOMINAL IN
hardness_rating115.0 ROCKWELL R NOMINAL SEAT
special_featuresA/K/A SEAT, LOWER
style_designatorPLAIN
nominal_thread_size5.250 INCHES SINGLE THREADED PORTION IN
body_inside_diameter4.625 INCHES NOMINAL IN
body_outside_diameter5.140 INCHES NOMINAL IN
seating_surface_shapeFLAT
end_item_identificationSEAWOLF CLASS SSN
NSN4820-01-442-0439
COMPONENT DIAGRAM
GATE VALVE — FULL OPEN OR FULL CLOSE ONLY Rising STEM BONNET FLOW → → FLOW SEATS — — SIZE: — · — · — PN: 218020209 · OEM ⚠ VERIFY BEFORE ORDERING Gate valves = FULL OPEN or FULL CLOSE only — never throttle. Partial opening causes seat erosion and vibration. ✓ BROKER TIP Rising stem shows valve position visually — easier maintenance. Non-rising stem saves headroom. PARTSTABLE TECHNICAL DRAWING — NOT TO SCALE
KEY FEATURES
•
BODY OUTSIDE DIAMETER: 5.140 INCHES NOMINAL IN
•
THREAD LENGTH: 0.752 INCHES NOMINAL SINGLE THREADED PORTION IN
•
HARDNESS RATING: 115.0 ROCKWELL R NOMINAL SEAT
•
STYLE DESIGNATOR: PLAIN
•
BODY INSIDE DIAMETER: 4.625 INCHES NOMINAL IN
•
NOMINAL THREAD SIZE: 5.250 INCHES SINGLE THREADED PORTION IN
TECHNICAL CHARACTERISTICS
OVERALL HEIGHT1.375 INCHES NOMINAL IN
BODY OUTSIDE DIAMETER5.140 INCHES NOMINAL IN
THREAD LENGTH0.752 INCHES NOMINAL SINGLE THREADED PORTION IN
HARDNESS RATING115.0 ROCKWELL R NOMINAL SEAT
STYLE DESIGNATORPLAIN
BODY INSIDE DIAMETER4.625 INCHES NOMINAL IN
NOMINAL THREAD SIZE5.250 INCHES SINGLE THREADED PORTION IN
SPECIAL FEATURESA/K/A SEAT, LOWER
THREAD CLASS3A SINGLE THREADED PORTION A
END ITEM IDENTIFICATIONSEAWOLF CLASS SSN
SUBSTITUTES & CROSS-REFERENCES 5
801-6556655 FIND A6Same NSN cross-reference
Same NSN cross-reference
Also cataloged under this NSN
2643-1002-63 FN A6Same NSN cross-reference
Same NSN cross-reference
Also cataloged under this NSN
2643-1002-63Reference document
Same NSN cross-reference
Reference document — Drawing number reference only
6556655Reference document
Same NSN cross-reference
Reference document — Drawing number reference only
801-6556655-A6Same NSN cross-reference
Same NSN cross-reference
Also cataloged under this NSN
LIFECYCLE
NSN statusActive· U.S. Government catalog
Acquisition advice: Normally procured from the manufacturer (OEM)Demilitarization required — critical (Q)
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FREQUENTLY ASKED QUESTIONS
What is 218020209?
218020209 is a SEAT,VALVE.
What parts can replace 218020209?
There are 5 known substitutes for 218020209: 801-6556655 FIND A6, 2643-1002-63 FN A6, 2643-1002-63 and 2 more. Substitute compatibility should be verified for your specific system.
What is the NSN for 218020209?
218020209 is cataloged in the U.S. Government catalog under NSN 4820-01-442-0439. This indicates validated use in U.S. government and defense supply chains.
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✓ PartsTable — the parts reference. Every fact cited to its source.
PartsTable Design LLC · partstable.com
U.S. Government catalog: edition PUBLOGDVD v12.0.0 (OCT 2026), edition date 2026-10-01, retrieved 2026-10-18.
PartsTable commercial catalog: edition Unified commercial catalog snapshot through 2026-09-28, edition date not on file, retrieved 2026-09-28.