The Seat,valve, cataloged under National Stock Number 4820-01-146-9996, is classified within Federal Supply Class 4820 (Valves, Nonpowered) of the Valves group. The manufacturer of record is William Powell Company, the Dba Powell Valve Div the Starflo Corporation. Government technical data includes 12 specifications, cited from the U.S. Government catalog. The record lists 2 manufacturer part numbers for this item, enabling identification through both NSN and commercial part number lookups. 1 additional reference document (drawings, advisory and superseded references) is recorded in the U.S. Government catalog. 2 items share a part number with this NSN in the catalog (possible match — not a government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 | 4820-01-146-9996 |
| Primary Part Number | 056950 ITEM 20 |
| Item Name | Seat,valve |
| FSC / FSG | 4820 / 48 — Valves, Nonpowered |
| Manufacturer | William Powell Company, the Dba Powell Valve Div the Starflo Corporation |
| Status | ACTIVE |
| Flange Seat to Disk End Height | 0.266 INCHES NOMINAL IN |
| Flange Diameter | 3.250 INCHES NOMINAL IN |
| Thread Length | 0.422 INCHES NOMINAL SINGLE THREADED PORTION IN |
| Body Stepped Inside Diameter | 2.375 INCHES MINIMUM AND 2.500 INCHES MAXIMUM FIRST STEP IN |
| Style Designator | THREADED FLANGED |
| Nominal Thread Size | 2.969 INCHES SINGLE THREADED PORTION IN |
| Under Flange Height | 0.547 INCHES NOMINAL IN |
| Thread Class | 2A SINGLE THREADED PORTION A |
| Thread Quantity Per Inch | 14 SINGLE THREADED PORTION |
| Material | STEEL OVERALL |
| Thread Series Designator | UNS SINGLE THREADED PORTION |
| Seating Surface Shape | FLAT |
| 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 |
|---|---|
| 056950 ITEM 20 PRIMARY | William Powell Company, the Dba Powell Valve Div the Starflo Corporation (USA) |
| 131235 PRIMARY | William Powell Company, the Dba Powell Valve Div the Starflo Corporation (USA) |
| Reference | Meaning |
|---|---|
| 056950 | D/9 Drawing number reference only William Powell Company, the Dba Powell Valve Div the Starflo Corporation |
NSN 4820-01-146-9996 is a Seat,valve, manufactured by William Powell Company, the Dba Powell Valve Div the Starflo Corporation, classified under FSC 4820, Valves, Nonpowered. Status: active.
NSN 4820-01-146-9996 has 2 manufacturer part numbers on file: 056950 ITEM 20 (William Powell Company, the Dba Powell Valve Div the Starflo Corporation), 131235 (William Powell Company, the Dba Powell Valve Div the Starflo Corporation).
2 possible matches (shared part number, not a government interchangeability claim): 4820-01-147-0064, 4320-01-621-3352. Verify interchangeability with system specifications before substitution.
Key specifications for 056950 ITEM 20: Flange Seat to Disk End Height: 0.266 INCHES NOMINAL IN; Flange Diameter: 3.250 INCHES NOMINAL IN; Thread Length: 0.422 INCHES NOMINAL SINGLE THREADED PORTION IN; Body Stepped Inside Diameter: 2.375 INCHES MINIMUM AND 2.500 INCHES MAXIMUM FIRST STEP IN. 12 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.