text: This invention relates to improvements in apparatus for gas humidification systems, particularly systems for humidifying oxygen prior to delivery to a patient. It is well known that the oxygen in conventional supply tanks used by hospitals has a relatively low humidity, and for this reason the oxygen cannot, in many instances, be directly administered to the patient. As a result, the oxygen is frequently passed through humidifiers prior to being delivered through a nasal cannula to the patient. The oxygen or oxygen-containing gas is usually humidified by bubbling the gas through a reservoir of water, saline solution, or other medicated solution.
  In order to maintain sterility, it has been previously proposed to utilize a standard intravenous solution bottle as the reservoir through which the gas is bubbled. The intravenous solution bottle has the advantage that it contains its own sterilized supply of water or other solution. Also the bottle is disposed of after use. Thus, assuming proper handling procedures, sterility is preserved. However, in order for standard intravenous solution bottles to be used for this purpose it is desired, from the point of view of economy, that standard or nearly standard stoppers be used on the bottles.
  When a standard stopper is used, it is necessary to puncture it and also to provide an arrangement that connects the oxygen supply to the apparatus. There must also be provided a supply of oxygen to the bottom of the bottle and also a means for delivery of the humidified gas to a nasal cannula. The set up or installation of the apparatus should be simple and yet maintain sterility. In particular there should be a minimum of difficulty in puncturing the stopper.
  In operation of the apparatus it sometimes happens that the free flow of humidified gas is obstructed by an occlusion in the nasal cannula, which usually is a flexible tube. When this occurs, the pressure in the bottle and in the fittings of the system can become excessive.