High Flow Check Valve 6000 psi: 1/2 NPT


The 684 check valve permits flow in one direction only, thus eliminating the possibility of back flow. It is suitable for any noncorrosive gas or liquid flow. The simple, reliable design uses O-ring seals to insure bubble tight sealing even with very low back pressures.

Type Check Valve
Maximum Rated Pressure 6000 psi
Nominal Orifice Size 0.047 in diameter
Inlet Port Size 1/2 in MNPT
Outlet Port Size 1/2 in FNPT
Outlet Pressure Rating 6000 si
Flow Coefficient 0.55 (0.28 in orifice)
Minimum Temperature -15ºF
Body Material Anodized Aluminum
Seal Materials Viton
Weight 4.9 oz (140 g)
Overall Length 2.6 in
Hex Diameter 1-3/8 in
Special Notes Open pressure: 3 to 8 psi

Typical Applications

  • Used between compressors and separators to prevent lead down via compressor valves and rings and to permit easy unloading of the compressor
  • Filling station control and logic
  • Numerous other control and logic functions in gas and liquid lines
  • Control in cascade filling systems