Abstract: A breathing circuit includes inspiratory and expiratory limbs, each having a respective electrically energizable heating circuit. The heating circuits are independently and selectively electrically energized through separate power circuits such as to control the temperature in each limb in a desired fashion so as to reduce rainout in the breathing circuit and particularly in the expiratory limb.

Abstract: A heated breathing circuit detection system verifies the proper set up and connection of a breathing circuit to a heater unit of a humidification system. The detection system automatically detects that the breathing circuit is connected to the heater unit, and the nature of the heating circuit(s) thereof. In one embodiment, the resistance of the heating circuit(s) is determined and compared to an expected resistance or range of acceptable resistances to determine if the heater circuit(s) is properly or actually attached and properly operating. The humidification system also has the ability to determine the delivery mode of the breathing circuit, i.e., whether a single inspiratory limb, or both inspiratory and expiratory limbs, is connected to the heater unit.

Abstract: A heater system is provided for a respiratory system having a PID feedback control in which the coefficients are adjusted, such as in a warm-up process, to correspond to a likely flow rate of gas through a chamber of heated water based on the difference between heat input and heat output in relation to a temperature set point without the need to directly monitor flow rate or humidity level. A steady-state adjustment of the coefficients based on the behavior of the measured temperature in relation to the set point is also disclosed.

Abstract: A breathing circuit includes inspiratory and expiratory limbs, each having a respective electrically energizable heating circuit. The heating circuits are independently and selectively electrically energized through separate power circuits such as to control the temperature in each limb in a desired fashion so as to reduce rainout in the breathing circuit and particularly in the expiratory limb.

Abstract: A heated breathing circuit detection system verifies the proper set up and connection of a breathing circuit to a heater unit of a humidification system. The detection system automatically detects that the breathing circuit is connected to the heater unit, and the nature of the heating circuit(s) thereof. In one embodiment, the resistance of the heating circuit(s) is determined and compared to an expected resistance or range of acceptable resistances to determine if the heater circuit(s) is properly or actually attached and properly operating. The humidification system also has the ability to determine the delivery mode of the breathing circuit, i.e., whether a single inspiratory limb, or both inspiratory and expiratory limbs, is connected to the heater unit.

Abstract: A heater system is provided for a respiratory system having a PID feedback control in which the coefficients are adjusted, such as in a warm-up process, to correspond to a likely flow rate of gas through a chamber of heated water based on the difference between heat input and heat output in relation to a temperature set point without the need to directly monitor flow rate or humidity level. A steady-state adjustment of the coefficients based on the behavior of the measured temperature in relation to the set point is also disclosed.