Abstract: A lung ventilator for supplying a mixture of oxygen and air to a patient as inspiration gas. The lung ventilator includes a compressor having an intake line for taking in oxygen and gas and supplying a mixture of the oxygen and gas to a main flow line as the inspiration gas to the patient. A recycle line is connected to the main flow line and the intake line of the compressor and a control arrangement is provided for enabling a flow of a portion of the inspiration gas in the main flow line in excess of the inspiration gas utilized by the patient into the recycle line for supply to the intake line of the compressor.

Abstract: A humidifier heats a gas to be supplied to a patient, for example, for anaesthesia in surgical operation or artificial respiration to cure difficulty of breathing, at an appropriate temperature and humidifies the same at an appropriate humidity.