The seal rings on this type of rotary union are closed when under pressure
When depressurised, the seal rings separate from each other, thereby creating a small gap.
DEUBLIN Pop-Off Designs – when rotation without media is possible
Pop-Off® seal rings:
The seal rings on this type of rotary union are closed when under pressure. When depressurised, the seal rings separate from each other, thereby creating a small gap (hence the Pop-Off ® name). This eliminates friction and seal wear during use without the need for cooling lubricant. This allows “dry running” of the rotary unions in the depressurised state for an unlimited period of time, even at high speeds.
Features: