Parker Hannifin Corporation
Parker Hannifin Corporation
Instrumentation Products Division
1005 A Cleaner Way
Huntsville, AL 35805 USA
Phone: +1 (256) 881-2040
Fax: +1 (256) 881-5072
Email: c-parker@parker.com
Website: www.parker.com
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Provide unidirectional flow and tight shut-off for liquids and gases with high reliability. When differential drops below cracking pressure*, valve shuts off. (Not for use as relief valve.)

Materials: 316 Stainless Steel: body, cover, poppet and cover gland. 300 Series Stainless Steel: spring Standard O-ring: Viton, for operation to 500° F (260°C). Buna-N or Teflon available for 250°F (121°C) or 400°F (204°C) respectively; specify when ordering.

*Cracking Pressure: 20 psi (1.38 bar) ±30%. Springs for higher cracking pressures (up to 100 psi (6.89bar)) available on special order for O-ring style check valves only.

Caution: While testing has shown O-Rings to provide satisfactory service life, both cyclic and shelf life may vary widely with differing service conditions, properties of reactants, pressure and temperature cycling and age of the O-ring. FREQUENT INSPECTIONS SHOULD BE MADE to detect any deterioration, and O-rings replaced as required.

Caution: See Tubing section for proper selection of tubing.

Note: All check valves are furnished complete with connection components unless otherwise specified.

All dimensions for reference only and subject to change.
For prompt service, Autoclave stocks select products. Consult your local representative.
All general terms and conditions of sale, including limitations of our liability, apply to all products and services sold.
Low-Pressure-Check-Valves_Low
O-Ring Check Valves Flow
Unit of Measure
Items Low-Pressure-Check-Valves_Low
QSO4400
QS Medium Pressure O-Ring Check Valves 		Low-Pressure-Check-Valves_Low
QSO6600
QS Medium Pressure O-Ring Check Valves 		Low-Pressure-Check-Valves_Low
QSO9900
QS Medium Pressure O-Ring Check Valves 		Low-Pressure-Check-Valves_Low
QSO12
QS Medium Pressure O-Ring Check Valves
Fits Connection Type N/A QS250 N/A QS375 N/A QS562 N/A QS750
Pressure Rating N/A 15000 psi1034.20 bar
Orifice N/A 0.188 in4.78 mm N/A 0.250 in6.35 mm N/A 0.359 in9.12 mm N/A 0.516 in13.11 mm
Rated Cv N/A 0.15 N/A 0.63 N/A 2.30 N/A 4.70
A - Length N/A 3.18 in80.77 mm N/A 3.56 in90.42 mm N/A 5.21 in132.33 mm N/A 6.40 in162.56 mm
B - Length N/A 2.56 in65.02 mm N/A 3.00 in76.20 mm N/A 4.50 in114.30 mm N/A 5.50 in139.70 mm
C - Length N/A 0.44 in11.18 mm N/A 0.53 in13.46 mm N/A 0.81 in20.57 mm N/A 1.03 in26.16 mm
D - Typical Hex N/A 0.63 in16.00 mm N/A 0.75 in19.05 mm N/A 1.19 in30.18 mm N/A 1.5 in38.1 mm
HEX N/A 0.81 in20.57 mm N/A 1.00 in25.40 mm N/A 1.75 in44.45 mm N/A 1.88 in47.75 mm
Tubing Engagement Depth N/A 0.55 in14.0 mm N/A 0.69 in17.6 mm N/A 0.81 in21.0 mm N/A 1.00 in25.4 mm
Note N/A N/A N/A N/A Dimension HEX is distance across flats.