Parker O-Ring Handbook.pdf

Section V – Dynamic O-Ring Sealing
5.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-2
5.2 Hydraulic Reciprocating O-Ring Seals . . . . . . . . . . 5-2
5.3 Surface Finishes . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-3
5.4 Temperature Effects on Dynamic Seals . . . . . . . . . . 5-5
5.5 Side Loads . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-5
5.6 Direction of Pressure . . . . . . . . . . . . . . . . . . . . . . . . 5-5
5.7 Shock Loads and Pressures . . . . . . . . . . . . . . . . . . . 5-5
5.8 High Frequency Motion or Vibration. . . . . . . . . . . . 5-6
5.9 Squeeze . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-6
5.10 Stretch . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-6
5.11 Friction. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-7
5.11.1 Break-Out Friction . . . . . . . . . . . . . . . . . . . . . 5-7
5.11.2 Running Friction . . . . . . . . . . . . . . . . . . . . . . 5-7
5.12 Calculate Rubbing Surface . . . . . . . . . . . . . . . . . . 5-8
5.13 Methods to Reduce Friction. . . . . . . . . . . . . . . . . . 5-8
5.14 Friction and Wear. . . . . . . . . . . . . . . . . . . . . . . . . . 5-8
5.14.1 Friction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-8
5.14.2 Pneumatic Seals . . . . . . . . . . . . . . . . . . . . . . 5-11
5.14.3 Wear . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-12
5.14.4 Interdependence of Friction Wear
and an Effective Seal . . . . . . . . . . . . . . . . . . . . . 5-12
5.15 Spiral Failure . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-13
5.15.1 Speed of Stroke . . . . . . . . . . . . . . . . . . . . . . 5-14
5.15.2 Lack of Lubrication . . . . . . . . . . . . . . . . . . . 5-14
5.15.3 Pressure Differential and Direction . . . . . . . 5-14
5.15.4 Squeeze . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-14
5.15.5 Shape of Groove and Split Groove. . . . . . . . 5-14
5.15.6 Temperature of Operation . . . . . . . . . . . . . . 5-14
5.15.7 Length of Stroke. . . . . . . . . . . . . . . . . . . . . . 5-14
5.15.8 Surface Finish. . . . . . . . . . . . . . . . . . . . . . . . 5-14
5.15.9 Back-Up Rings. . . . . . . . . . . . . . . . . . . . . . . 5-14
Parker O-Ring Handbook
5.16 Modifi cations for Special Applications . . . . . . . . 5-14
5.16.1 Small Amount of Leakage . . . . . . . . . . . . . . 5-15
5.16.2 Early Stress-Aging . . . . . . . . . . . . . . . . . . . . 5-15
5.16.3 Low Temperature Leakage. . . . . . . . . . . . . . 5-15
5.16.4 Excessive Swell (above 20%) . . . . . . . . . . . 5-15
5.17 Gland Dimensions for Reciprocating
Hydraulic O-Ring Seals . . . . . . . . . . . . . . . . . . . . . 5-15
5.18 Floating Glands . . . . . . . . . . . . . . . . . . . . . . . . . . 5-15
5.19 Pneumatic Reciprocating O-Ring Seals. . . . . . . . 5-16
5.20 Temperature . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-16
5.21 Silicone Compounds . . . . . . . . . . . . . . . . . . . . . . 5-16
5.22 High-Pressure. . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-16
5.23 Lubrication. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-16
5.24 Gland Dimensions . . . . . . . . . . . . . . . . . . . . . . . . 5-16
5.25 Floating Seal . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-16
5.26 Uni-Directional Gland . . . . . . . . . . . . . . . . . . . . . 5-17
5.27 Rotary Seal. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-17
5.28 Oscillating Seal . . . . . . . . . . . . . . . . . . . . . . . . . . 5-19
5.29 Seat Seal. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-19
5.30 Drive Belts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-20
5.30.1 Calculation of Drive Belt Open Design . . . . 5-20
5.30.2 Calculation of Drive Belt Crossed Design . . 5-21
5.31 O-Ring Glands . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-21
5.31.1 O-Ring Glands for Aerospace
Hydraulic Packings and Gaskets . . . . . . . . . . . . 5-21
5.31.2 O-Ring Glands for Industrial
Reciprocating Seals . . . . . . . . . . . . . . . . . . . . . . 5-30
5.31.3 O-Ring Glands for Pneumatic
Floating Piston Ring Seals . . . . . . . . . . . . . . . . . 5-35
5.31.4 O-Ring Glands for Rotary Seals . . . . . . . . . 5-39
5.32 Dynamic Vacuum Sealing . . . . . . . . . . . . . . . . . . 5-44
Parker Hannifi n Corporation • O-Ring Division
2360 Palumbo Drive, Lexington, KY 40509
Phone: (859) 269-2351 Fax: (859) 335-5128
www.parkerorings.com
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Dynamic O-Ring Sealing