PartsTable TECHNICAL DATA SHEET
JULY 2026Technical Data Sheet

R639-9Seat,valve

Derbyshire Machine & Tool Co · NSN 4820-00-036-2491 · FSC 4820 · No Item Name Available
Verified by PartsTable
NSN 4820-00-036-2491 — this item is cataloged by the U.S. Government under National Stock Number 4820-00-036-2491. Primary manufacturer part number: R639-9.
Features
  • Seat,valve — FSC 4820
  • 3 verified cross-references
  • Primary manufacturer: Derbyshire Machine & Tool Co
Applications
  • Flow control in piping systems
  • Pressure regulation
  • Steam and fluid isolation
General Description

The Seat,valve, cataloged under National Stock Number 4820-00-036-2491, is classified within Federal Supply Class 4820 (No Item Name Available) of the Valves group. The primary manufacturer of record is Derbyshire Machine & Tool Co. This item has 3 commercial cross-references from 2 manufacturers, enabling identification through both NSN and commercial part number lookups. 12 verified substitutes exist in the FLIS interchangeability database. Current acquisition status: Active.

Catalog Facts
Item NameSeat,valve
FSC / FSG4820 — No Item Name Available (FSG 48)
ManufacturersSpx Flow Us, Llc Dba Spx Valves & Controls (CAGE 97370); Derbyshire Machine & Tool Co (CAGE 71905)
Technical Specifications
ParameterValue
NSN4820-00-036-2491
Primary Part NumberR639-9
Item NameSeat,valve
FSC / FSG4820 / 48 — No Item Name Available
ManufacturerDerbyshire Machine & Tool Co
StatusACTIVE
Lifecycle & Compliance
Acquisition StatusACTIVE
HAZMATNo
Verified Substitutes 12
4730-00-127-88226848 INTERCHANGEABLE
Clamp,hose
Epicor Industries Inc Ideal Div
2815-00-146-7546 INTERCHANGEABLE
Tube,water
4320-00-364-64461976 INTERCHANGEABLE
Impeller,pump,centrifugal
Brinkley Technology Group Llc Dba Hercules Manufacturing
4730-00-419-30861115950-1 INTERCHANGEABLE
Clamp,hose
Us Army Aviation and Missile Command
3110-00-516-5289203TF INTERCHANGEABLE
Bearing,ball,annular
Fag Bearings Corporation
5950-00-538-67736448-1 INTERCHANGEABLE
Coil,electrical
Te Connectivity Corporation
5325-00-637-4156 INTERCHANGEABLE
Grommet,nonmetallic
6135-00-812-9039ZM9 INTERCHANGEABLE
Battery,nonrechargeable
Yosemite Investment Inc Dba North American Capacitor Co
6135-00-985-7845003-360013R00 INTERCHANGEABLE
Battery,nonrechargeable
Insitu, Inc.
5120-01-130-8880 INTERCHANGEABLE
Wrench,torque
Cross-Reference Index
Part NumberManufacturer
6448RV Spx Flow Us, Llc Dba Spx Valves & Controls (USA)
6448 Spx Flow Us, Llc Dba Spx Valves & Controls (USA)
R639-9 PRIMARY Derbyshire Machine & Tool Co (USA)
Related Parts
4730-00-127-8822INTERCHANGEABLE
CLAMP,HOSE
6848
2815-00-146-7546INTERCHANGEABLE
TUBE,WATER
4320-00-364-6446INTERCHANGEABLE
IMPELLER,PUMP,CENTRIFUGAL
1976
4730-00-419-3086INTERCHANGEABLE
CLAMP,HOSE
1115950-1
3110-00-516-5289INTERCHANGEABLE
BEARING,BALL,ANNULAR
203TF
5950-00-538-6773INTERCHANGEABLE
COIL,ELECTRICAL
6448-1
5325-00-637-4156INTERCHANGEABLE
GROMMET,NONMETALLIC
6135-00-812-9039INTERCHANGEABLE
BATTERY,NONRECHARGEABLE
ZM9
6135-00-985-7845INTERCHANGEABLE
BATTERY,NONRECHARGEABLE
003-360013R00
5120-01-130-8880INTERCHANGEABLE
WRENCH,TORQUE
6680-01-136-3218INTERCHANGEABLE
DIAPHRAGM,LIQUID SIGHT INDICATOR
6448-13
5306-01-203-9050INTERCHANGEABLE
ROD,THREADED END

Frequently Asked Questions

What is NSN 4820-00-036-2491?

NSN 4820-00-036-2491 is a Seat,valve, manufactured by Derbyshire Machine & Tool Co, classified under FSC 4820 (No Item Name Available). Status: active.

What are the part numbers for NSN 4820-00-036-2491?

NSN 4820-00-036-2491 has 3 cross-referenced part numbers: 6448RV (Spx Flow Us, Llc Dba Spx Valves & Controls), 6448 (Spx Flow Us, Llc Dba Spx Valves & Controls), R639-9 (Derbyshire Machine & Tool Co).

What NSN replaces 4820-00-036-2491?

There are 12 known substitutes for 4820-00-036-2491: 4730-00-127-8822, 2815-00-146-7546, 4320-00-364-6446 and 9 more. Verify interchangeability with system specifications before substitution.

Validated with multiple authoritative sources, including Government, OEM, and Certified sources.
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