Which type of reciprocating pump can safely run dry?

A diaphragm pump is specifically designed to handle certain challenging operating conditions, including the ability to operate safely when the pump is running dry. This characteristic is attributed to its unique mechanism, which uses a flexible diaphragm to create a pumping action. When the diaphragm moves, it creates a vacuum that draws fluid into the chamber. If there is no fluid present, the diaphragm can continue to oscillate without causing damage to the pump or generating excessive heat, unlike other types of pumps that require fluid for cooling and lubrication.

In contrast, other pump types, such as gear pumps, piston pumps, and centrifugal pumps, can suffer serious damage if run dry. Gear pumps rely on constant lubrication from the fluid being pumped to maintain their internal components, while piston pumps can experience wear and potential failure if the piston operates without lubrication. Centrifugal pumps typically require fluid to maintain the balance and create the necessary suction; running them dry can lead to overheating and mechanical failures.

Therefore, the diaphragm pump's construction and operating principle allow it to handle dry runs safely, making it the correct answer to the question.