The Valve,safety Relief, cataloged under National Stock Number 4820-01-435-8842, is classified within Federal Supply Class 4820 (Valves, Nonpowered) of the Valves group. The manufacturer of record is Hydraulics International, Inc. Dba Hydraulics International Inc. Government technical data includes 15 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through both NSN and commercial part number lookups. 3 additional reference documents (drawings, advisory and superseded references) are recorded in the U.S. Government catalog. Current acquisition status: Active.
| Parameter | Value |
|---|---|
| NSN | 4820-01-435-8842 |
| Primary Part Number | 684-1-1/2SS1 |
| Item Name | Valve,safety Relief |
| FSC / FSG | 4820 / 48 — Valves, Nonpowered |
| Manufacturer | Hydraulics International, Inc. Dba Hydraulics International Inc |
| Status | ACTIVE |
| Flow Control Device | POPPET |
| Connection Style | PLAIN (PIPE) FIRST END |
| Minimum Operating Temp | -40.0 FAHRENHEIT DEGF |
| Connection Type | THREADED EXTERNAL PIPE FIRST END |
| Style Designator | STRAIGHT THRU |
| Thread Direction | RIGHT-HAND FIRST END |
| Nominal Thread Size | 0.500 INCHES FIRST END IN |
| Maximum Operating Temp | 225.0 FAHRENHEIT SINGLE RESPONSE DEGF |
| Media for Which Designed | AIR SINGLE RESPONSE |
| Material | COPPER ALLOY BODY |
| Material | STEEL COMP 303 FLOW CONTROL DEVICE |
| Material | RUBBER SYNTHETIC SEAT |
| Thread Series Designator | NPT FIRST END |
| Opening Pressure Setting | 5.0 POUNDS PER SQUARE INCH LBS |
| 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 |
|---|---|
| 1741AS568-1 | Naval Air Systems Command Managed Original Design Activity Not Material/parts Supplier (USA) |
| 684-1-1/2SS1 PRIMARY | Hydraulics International, Inc. Dba Hydraulics International Inc (USA) |
| Reference | Meaning |
|---|---|
| 1741AS568 | D/9 Drawing number reference only Naval Air Systems Command Managed Original Design Activity Not Material/parts Supplier |
| 684-1-1/2B1 | 5/9 Secondary reference Parker-Hannifin Corporation Dba Pneutronics Div Hydraulic Valve Division |
| 684-1-1/2B1 | 5/9 Secondary reference U.S. Government activity |
NSN 4820-01-435-8842 is a Valve,safety Relief, manufactured by Hydraulics International, Inc. Dba Hydraulics International Inc, classified under FSC 4820, Valves, Nonpowered. Status: active.
NSN 4820-01-435-8842 has 2 manufacturer part numbers on file: 1741AS568-1 (Naval Air Systems Command Managed Original Design Activity Not Material/parts Supplier), 684-1-1/2SS1 (Hydraulics International, Inc. Dba Hydraulics International Inc).
Key specifications for 684-1-1/2SS1: Flow Control Device: POPPET; Connection Style: PLAIN (PIPE) FIRST END; Minimum Operating Temp: -40.0 FAHRENHEIT DEGF; Connection Type: THREADED EXTERNAL PIPE FIRST END. 15 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.