**Application description: Hydraulic Cylinder, U. S. Customary Units (inches)**

- 5" dynamic stroke

- Piston diameter: 2.992" ±.002

- Bore diameter: 3.000" ±.002

- 200 psi maximum pressure

- .103" cross-section Quad-Ring® Brand seal
- No side loading or eccentricity

Ring Size | Cross Section | DYNAMIC Recommended Gland Depth "C" |
STATIC Recommended Gland Depth "C |
AXIAL GROOVE Width "D" +.005/-.000 |

Q4102 - Q4178 | .103 ±.003 | .094 | .089 | .115 |

**Calculate the Seal Groove Diameter:**

Groove Diameter

= Maximum Bore Diameter - (2 x Dynamic Gland Depth)

= 3.002 - ( 2 x .094)

= 2.814 -.000/+ .002

(Recall the gland depth values in the chart are given as radial values)**From the chart, the groove width is**.115 -.000/+.005**Calculate the Minimum Gland Volume:**Minimum Gland Volume

= ((Min Bore Dia. - Max Groove Dia./ 2) x Min Groove Width

= ((2.998 - 2.816 )/2) X .115

= .0105 in2**Calculate the Maximum Quad-Ring® Brand Seal Volume:**Maximum Quad-Ring® Brand Volume

= (Max Quad-Ring® Brand Cross-section)2 X .8215

= (.106)2 X .8215

= .0092 in2

**Compare the Minimum Gland Volume to the Maximum Quad-Ring® Brand Volume**In this application the maximum seal volume is less than the minimum gland volume,

so the seal should function satisfactorily.

**Calculate the Minimum and Maximum Seal Squeeze**Max Seal Squeeze = 1 - (Min Gland Depth / Max Seal Cross-section)

a.

Min Gland Depth = (Min Bore Dia. - Max Groove Dia.) / 2

= (2.998 - 2.816) / 2

= .091

Max Seal Squeeze = 1 - (.091/.106)

= .141

= 14.1%

**b.**Min Seal Squeeze = 1 - (Max Gland Depth / Min Seal Cross-section)

Max Gland Depth = (Max Bore Dia. - Min Groove Dia.) / 2

= (3.002 - 2.814) / 2

= .094

Min Seal Squeeze = 1 - (.094/.100)

= .06

= 6%

*Therefore, sufficient squeeze should exist to seal this application.*

**Calculate the Maximum Clearance and evaluate possible extrusion problems**Max Radial Clearance = (Max Bore Dia. - Min Piston Dia.) / 2

= (3.002 - 2.990) /2

= .006

From the Clearance Chart, the recommended max clearance for a Quad-Ring® Brand with a hardness of 70 Shore A at 200 psi is .009. The seal should function properly.

**Select the Seal Size**Refer to the Selection Guide and turn to the section which lists the seals having a .103 cross-section. Since in this application the sealing is occurring on the bore, use the Bore column to look up the seal size for a 3.000" bore. The correct seal is a number 4 -149 (with the 4 prefix signifying a Quad-Ring® Brand seal). Note the seal inside diameter, which is 2.800 ±.022. This will be used below.

**Calculate the Installed Seal Stretch**Stretch % = ((Installed Seal ID - Original Seal Inside Diameter) /

Original Seal Diameter) x 100

= ((Groove Diameter - Original Seal Inside Diameter) /

Original Seal Diameter) x 100

= ((2.814 - 2.800) / 2.800) x 100

= (.014 / 2.800) * 100 = .5 %

*This stretch is low and will not cause significant cross-sectional reduction.*