Gasboy Gilbarco Global Pumping Unit Operation Manual - Manual (Page 39)

MDE-4447A Global Pumping Unit Operation and Service Manual · May 2008 Page 35
Vapor Lock Causes Reasons for Vapor Lock
It takes 1 inch of vacuum by the pump to overcome the restriction of 60 feet of horizontal
piping from the tank to the pump. See
Figure 6-8 .
Figure 6-8: Compensating for Horizontal Piping
2 To obtain the inches of vacuum required to deliver the product, simply add A, B and C.
With 9.4 inches of suction to work with and only 8 inches of vacuum required, conditions are
normal and the pump delivers the product without vapor locking.
Note: This condition exists when the product is at 60° F.
A. 9 feet of lift = 6 inches of suction
B. Angle check or foot valve= 1 inch of suction
C. 60 feet horizontal run= 1 inch of suction
TOTAL 8 inches of suction
60 Feet of Horizontal Piping = 1 inch of Vacuum
60ºF