Technology Today: TIME TO PRIME

摘要

Fire Pump Design On Motor-ized vehicles underwent a radical change starting as early as 1912. That was when the basic fire pump designs started to change over from the positive displacement type to centrifugal pumps. This was a very gradual transition and typically started with the larger city/municipal departments with pressurized hydrant systems switching over first. Rural departments that employed drafting more frequently generally used the positive displacement pumps a little longer, for reasons explained below. Seagrave and Van-Pelt were two truck builders that pioneered the use of centrifugal pumps. By the end of World War II, the centrifugal pump dominated the fire service. However, centrifugal fire pumps require that the suction be completely flooded with water to produce pressure; otherwise, the operator must use a primer to completely remove the air from the pump suction by providing enough vacuum to bring water into the suction hoses and the fire pump inlet.