There are pumps on the market that are self-priming and can run dry indefinitely without doing damage to the pump.
Frequently Asked Questions About Peristaltic Pumps - Lead Fluid
Centrifugal vs. Positive Displacement Pump
PD' Positive Displacement Pumps PD75
Air Operated Diaphragm Pumps
Penn Valley Pump - The Original Double Disc Pump Technology
CHAPTER 4: Rough Vacuum Regime – Introduction to Vacuum Technology
Positive Displacement Pump or Centrifugal - Which one do you need
16 Key Benefits of AODD Pumps
Centrifugal vs. Positive Displacement Pump
Penn Valley Pump - The Original Double Disc Pump Technology