The Valve,check, cataloged under National Stock Number 4820-00-191-7127, is classified within Federal Supply Class 4820 (Valves, Nonpowered) of the Valves group. The manufacturer of record is Meggitt Troy Inc. Government technical data includes 25 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through both NSN and commercial part number lookups. 1 additional reference document (drawings, advisory and superseded references) is recorded in the U.S. Government catalog. Current acquisition status: Active.
| Parameter | Value |
|---|---|
| NSN | 4820-00-191-7127 |
| Primary Part Number | 665-0019 |
| Item Name | Valve,check |
| FSC / FSG | 4820 / 48 — Valves, Nonpowered |
| Manufacturer | Meggitt Troy Inc |
| Status | ACTIVE |
| Flow Control Device | POPPET |
| Connection Style | FLARED (TUBE) ALL ENDS |
| Mounting Position | HORIZONTAL |
| Connection Type | THREADED EXTERNAL TUBE ALL ENDS |
| Style Designator | STRAIGHT THRU |
| Material Document and Classification | QQ-A-225/6,ALLOY 2024,T4 FED SPEC SINGLE MATERIAL RESPONSE BODY |
| Material Document and Classification | QQ-A-225/6,ALLOY 2024,T4 FED SPEC SINGLE MATERIAL RESPONSE SEAT |
| Material Document and Classification | QQ-A-225/6,ALLOY 2024,T4 FED SPEC SINGLE MATERIAL RESPONSE FLOW CONTROL DEVICE |
| Nominal Outside Diameter Tube Accommodated | 0.250 INCHES ALL ENDS IN |
| Operating Pressure | 3000.0 POUNDS PER SQUARE INCH (PSI) MAXIMUM SINGLE RESPONSE LBS |
| Thread Direction | RIGHT-HAND ALL ENDS |
| Nominal Thread Size | 0.438 INCHES ALL ENDS IN |
| Seat Angle | 37.0 DEGREES ALL ENDS |
| Maximum Operating Temp | 250.0 FAHRENHEIT SINGLE RESPONSE DEGF |
| Disk Loading Method | SPRING |
| Media for Which Designed | AIR SECOND RESPONSE |
| Media for Which Designed | WATER, FRESH FOURTH RESPONSE |
| Media for Which Designed | AMMONIA, GASEOUS THIRD RESPONSE |
| Media for Which Designed | ACETYLENE FIRST RESPONSE |
| Thread Class | 3A ALL ENDS A |
| Material | ALUMINUM ALLOY 2024 FLOW CONTROL DEVICE |
| Material | ALUMINUM ALLOY 2024 BODY |
| Material | ALUMINUM ALLOY 2024 SEAT |
| Thread Series Designator | UNF ALL ENDS |
| Valve Operation Method | AUTOMATIC |
| 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 |
|---|---|
| 665-0019 | Meggitt Troy Inc (USA) |
| Reference | Meaning |
|---|---|
| 249A4TT | 3/2 Design control — primary reference U.S. Government activity |
NSN 4820-00-191-7127 is a Valve,check, manufactured by Meggitt Troy Inc, classified under FSC 4820, Valves, Nonpowered. Status: active.
NSN 4820-00-191-7127 has 1 manufacturer part number on file: 665-0019 (Meggitt Troy Inc).
Key specifications for 665-0019: Flow Control Device: POPPET; Connection Style: FLARED (TUBE) ALL ENDS; Mounting Position: HORIZONTAL; Connection Type: THREADED EXTERNAL TUBE ALL ENDS. 25 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.