What determines the gallon per minute (gpm) delivery of a gear pump?

The correct answer focuses on the space around the gears and the revolutions per minute (rpm) of the pump. The flow rate, measured in gallons per minute (gpm), is primarily influenced by the design of the gear pump, which relies on the clearances between the gears and the casing. This design determines how much fluid can be moved through the pump as the gears rotate.

As the gears turn, they create a continuous flow by trapping fluid between the gear teeth and the casing. The rpm of the pump directly affects the number of times the gears sweep through the same volume of fluid within a given period, thereby impacting the flow rate. A higher rpm results in more rotations per minute, leading to increased fluid movement and, consequently, more gpm delivered.

Other options do not accurately capture the essential relationship between gear spacing and rpm. The size of the pump and diameter of the discharge, while they may influence performance, are not the primary determinants of flow rate like the referenced factors. Additionally, the number of gears or size of pipe relates more to system dynamics than the core mechanics of a gear pump’s operation. Thus, it is the combination of the effective spacing around the gears and their operational speed that essentially dictates the delivery rate in gpm