Apparatus for promoting waste-free primary flow in a patient monitoring device is disclosed and includes a waste trap with a body defining a waste chamber with the body including an entry port for communication with a primary channel of the device, and an exit port for communication with a secondary...http://www.google.de/patents/US5231991?utm_source=gb-gplus-sharePatent US5231991 - Apparatus for promoting waste-free primary flow in a patient monitoring device
