"Purging" normally meant "expulsion from Party membership" and carried no actual punishment. For criminals who were purged, that also included jail time or even execution. The myth that everyone purged was executed comes from the Black Book of Communism, anti-communist mythology that the creators have since denounced, and even included Nazis killed during World War II as "victims of Communism."
You can feel free to read history books like the ones I have linked.