.........The Fusion of Art and Science tm .........
G. Finkenbeiner Inc. 33 Rumford Ave Waltham, MA 02453. Telephone: (800)5526182, 7818993138. Fax 7816474044
PRESSURE
Since fused quartz is utilized in applications involving internal pressures, it is sometimes helpful to know the maximum pressure which can be applied to a certain size tube. The following formula will approximate this information at room temperature.
S = p*r/t
Where:
S = Hoop Stress in Pa
p = Working pressure (Pa)
r = Inside Radius of Tube (mm)
t = Wall Thickness (mm)
This formula is not applicable when the internal pressure
exceeds 7x10 ^{5} Pa (100 psi).
CFQ Rupture Formula For Discs And Plates
Calculating pressure differential is also required for many applications of stressed fused quartz discs, plates, and sight glasses.
The formula which follows can be used for room temperature applications of circular parts with either clamped or unclamped edges.
Clamped

Unclamped



Where:
p = Pressure differential, PSI
d_{o} = Unsupported disc diameter, mm (for plates substitute width)
Smax = Maximum stress (approx. 7 to 1 safety factor) 1000 PSI
t = Disc thickness, mm
However, the following factors will affect the strength of these parts and must be considered when using the formulae: