Page 397 - Centrifugal Pumps 2E
P. 397
362 Centrifugal Pumps: Design and Application
where P h = AP(b - k), lb/in 2
P = pressure differential across seal face, lb/in 2
b = seal balance
k = pressure gradient factor
The pressure gradient factor is normally taken as 0.5 for a given instal-
lation. The mechanical pressure for a seal is:
where F sp = seal spring load, Ib
2
a 0 = seal face area in.
then the actual face pressure can be expressed as:
The actual face pressure is used in the estimate of the operating pres-
sure-velocity for a given seal installation.
Figure 17-5. Pressure wedge opening force at the seal faces.
