F-12000 atmospheres 
| on piston 
I ,—_ 16,000 atmos 
on packing 
Cylinder 
VZLILLLLLLLLLLLL LL LLL 
(a) flat rubber stopper 
From ‘‘High-Pressure Phenomena with Application 
to Geophysics,’’ in Modern Physics for the Engineer, 
edited by L. N. Ridenour. McGraw-Hill, 1954. Used (b) stopper in high- 
with permission of McGraw-Hill Book Company. pressure apparatus 
Figure 69. Examples of partially unsupported gasket concept (Griggs, 1954). 
(a) Unloaded elastomeric O-ring used as a 
piston ring in a hydraulic cylinder. Note 
slight radial compression and considerable 
clearance in axial direction. 
L, (b) With the piston working, the pressure drop 
aarti is the total working pressure, and the piston 
seal operates with essentially zero leakage. 
Lubrication at the velocity interface, A, is 
boundary lubrication at best, even with a 
e hydraulic fluid of recognized lubricity. 
Figure 70. Action of an elastomeric O-ring used as a piston ring. 
e2 
