An endless path calibration system comprising a sensor cassette having a flow-through passage and at least one sensor to be calibrated, a chamber coupled to the sensor cassette to define an endless path and a sterile calibration liquid in the endless path. A gas injection passage for injecting gas into...http://www.google.es/patents/US5057278?utm_source=gb-gplus-sharePatente US5057278 - Sterile loop calibration system
