Which pumps can I run dry?

Q: Which pumps can I run dry?
A: Diaphragm pumps, piston pumps and peristaltic pumps can be run dry for any length of time. Centrifugal, rotary vane, and gear pumps should not be run dry; exceptions are if the gear or impeller is made of a self-lubricating material such as RYTON in which case the pump can be run for a few minutes while priming.