How can the gpm delivery of a fixed-displacement pump be altered?

The delivery of a fixed-displacement pump, measured in gallons per minute (gpm), can be altered by changing the speed of the pump. A fixed-displacement pump moves a specific volume of fluid with each rotation or cycle, meaning its flow rate is directly proportional to its speed. If you increase the speed at which the pump operates, it will deliver more gpm, as it will complete more cycles in a given amount of time. Conversely, slowing down the pump reduces the flow rate.

The other factors, such as changing the viscosity of the fluid, modifying the pump's design, or adjusting fluid temperature, can affect the performance of the pump but do not alter the fundamental delivery rate determined by the fixed-displacement nature of the pump itself. These factors may influence aspects like pressure or efficiency but won't change the delivery rate defined by the pump's mechanics. Therefore, the correct way to change the gpm delivery of a fixed-displacement pump is indeed by altering its speed.