There is no damage caused by dry running / overheating. Due to the compressed air operation electrical connections are not necessary and the pumps are cooled with the compressed air itself.
Media with solids such as stones can be transfer. By adjusting either the air regulator or a liquid discharge valve it is possible to control the flow rate and pressure. If a valve is closed the pumps can handle this without problems. The TC-X pumps can operate dry and generate relatively high Vacuum Pressure, so the pump is self-priming.
Flammable liquids can be operated with appropriate grounding as well.