The Seat,valve, cataloged under National Stock Number 4820-01-103-3291, is classified within Federal Supply Class 4820 (Valves, Nonpowered) of the Valves group. The manufacturer of record is The Walworth Company. Government technical data includes 14 specifications, cited from the U.S. Government catalog. The record lists 1 manufacturer part number for this item, enabling identification through both NSN and commercial part number lookups. 3 additional reference documents (drawings, advisory and superseded references) are recorded in the U.S. Government catalog. 2 items share a part number with this NSN in the catalog (possible match — not a government interchangeability claim). Current acquisition status: Active.
| Parameter | Value |
|---|---|
| NSN | 4820-01-103-3291 |
| Primary Part Number | 2621-922-02 ITEM 56-3IN |
| Item Name | Seat,valve |
| FSC / FSG | 4820 / 48 — Valves, Nonpowered |
| Manufacturer | The Walworth Company |
| Status | ACTIVE |
| Flange Seat to Disk End Height | 0.250 INCHES NOMINAL IN |
| Flange Diameter | 3.719 INCHES NOMINAL IN |
| Thread Length | 0.469 INCHES NOMINAL SINGLE THREADED PORTION IN |
| Style Designator | THREADED FLANGED |
| Material Document and Classification | QQ-N-288 FED SPEC SINGLE MATERIAL RESPONSE OVERALL |
| Body Inside Diameter | 2.875 INCHES NOMINAL IN |
| Nominal Thread Size | 3.469 INCHES SINGLE THREADED PORTION IN |
| Under Flange Height | 0.469 INCHES NOMINAL IN |
| Thread Class | 3A SINGLE THREADED PORTION A |
| Thread Quantity Per Inch | 12 SINGLE THREADED PORTION |
| Material | NICKEL ALLOY A OVERALL |
| Seat Angle in Deg | 15.000 NOMINAL |
| Thread Series Designator | UNS SINGLE THREADED PORTION |
| Seating Surface Shape | ANGULAR |
| Acquisition Status | ACTIVE |
| DEMIL Code | DEMIL A — No Demilitarization Required |
| Hazard | No hazard code in the DLA record (HMIC N) |
| Criticality Code | X |
| Part Number | Manufacturer |
|---|---|
| 2621-922-02 ITEM 56-3IN PRIMARY | The Walworth Company (USA) |
| Reference | Meaning |
|---|---|
| 845-1889553 | D/9 Drawing number reference only U.S. Government activity |
| 2621-922-02 ITEM 56-3IN | 5/9 Secondary reference U.S. Government activity |
| 845-1889553 PIECE 31-3IN | 5/2 Secondary reference U.S. Government activity |
NSN 4820-01-103-3291 is a Seat,valve, manufactured by The Walworth Company, classified under FSC 4820, Valves, Nonpowered. Status: active.
NSN 4820-01-103-3291 has 1 manufacturer part number on file: 2621-922-02 ITEM 56-3IN (The Walworth Company).
2 possible matches (shared part number, not a government interchangeability claim): 4820-01-185-6665, 4820-01-187-1467. Verify interchangeability with system specifications before substitution.
Key specifications for 2621-922-02 ITEM 56-3IN: Flange Seat to Disk End Height: 0.250 INCHES NOMINAL IN; Flange Diameter: 3.719 INCHES NOMINAL IN; Thread Length: 0.469 INCHES NOMINAL SINGLE THREADED PORTION IN; Style Designator: THREADED FLANGED. 14 specifications are documented in the U.S. Government catalog.
No hazard code in the DLA record (HMIC N). Hazard information on this page is shown exactly as it appears in the DLA record.
U.S. Government catalog: edition PUBLOGDVD v12.0.0 (OCT 2026), edition date 2026-10-01, retrieved 2026-10-16.
U.S. Government catalog: edition PUBLOGDVD v12.0.0 (OCT 2026), edition date 2026-10-01, retrieved 2026-10-18.