Which statement is false concerning rotary pumps?

Rotary pumps are designed to move fluids primarily through the action of rotating components within the pump. One defining feature of many rotary pumps is their ability to create a strong vacuum, which allows them to effectively draw various fluids into the system. This characteristic makes them suitable for different applications, including those that require the handling of both low and relatively high viscosity liquids. Additionally, many rotary pumps offer adjustable speed ranges, allowing operators to control the flow rate to meet specific system requirements.

In the context of starting up a rotary pump, it's important to recognize that not all rotary pumps require priming before operation. Priming involves filling the pump with liquid to eliminate air and create the necessary suction for the pump to operate correctly. Some designs, particularly self-priming rotary pumps, can automatically purge air and will not require manual priming. This characteristic distinguishes them from many other types of pumps, particularly those that are more dependent on being primed to function effectively. Thus, stating that rotary pumps need priming before startup is not universally accurate, making it the false statement in this context.