Gasboy Gilbarco Global Pumping Unit Operation Manual - Manual (Page 36)

Reasons for Vapor Lock Vapor Lock Causes
Page 32 MDE-4447A Global Pumping Unit Operation and Service Manual · May 2008
Vapor Pressure
Vapor Pressure (the amount of pressure required to keep the product in a liquid form at 60° F)
of today's product is approximately 10 PSI. See
Figure 6-2 on page 32 .
Figure 6-2: Vapor Pressure
Working Pressure
The difference between Atmospheric Pressure and Vapor Pressure is known as the Working
Pressure. The Working Pressure is all that the pump can create without the product turning to
vapor. See
Figure 6-3 .
Figure 6-3: Working Pressure
14.7 PSI Atmospheric Pressure
- 10.0 PSI Vapor Pressure
4.7 PSI Working Pressure
10 PSI required to keep
product in liquid form
60º F
14.7 PSI
10.0 PSI
4.7 PSI
Atmospheric
Pressure
Less
Vapor Pressure
equals
Working Pressure
60º F