Conduit overheating detection system

A humidification apparatus for humidifying a gases flow to be supplied to a patient or other person in need of such gases comprising:

• humidification chamber means adapted to hold a quantity of water and having an inlet and an outlet to allow said gases flow to pass through said humidification chamber means,
• heating means provided adjacent said humidification chamber means and adapted to provide heat to said quantity of water in said humidification chamber means in order to provide water vapour to said gases flow passing through said humidification chamber means, said heating means utilising a measurable quantity of power,
• gases transportation pathway means connected to said outlet of said humidification chamber means to convey said gases flow to said patient or other person in need of such gases,
• gases transportation pathway heating means that is energisable to supply heat to said gases flow along at least a part of the length of said gases transportation pathway means,
• detecting means which includes means to detect the current in said gases transportation pathway heating means, and
• control means, including power supply means, which implements an algorithm that causes the control means to:
• i) receive input of said current in said gases transportation pathway heating means from said detecting means, and
• ii) if said current is outside a safe current region, then reduce the power supplied by said power supply means to said gases transportation pathway heating means so as to alter the current in said gases transportation pathway heating means to within said safe current region and prevent occurrence of said conduit and said heating element overheating, then
• iii) after a predetermined time increase said power supplied by said power supply means to said gases transportation pathway heating means.

A conduit overheating detection system for a respiratory conduit heating element comprising:

• a conduit, comprising two limbs, one limb being an inspiratory limb of said respiratory conduit and the other being an expiratory limb of said respiratory conduit, said conduit having a heating element disposed within it, where, in use, the current flowing in the first part of said heating element in said first limb differs to that of the current flowing in the second part of the heating element in said second limb,
• detecting means which includes means to detect a first current and a second current in said first part of said heating element and said second part of said beating element respectively, and
• control means which implements an algorithm that causes the control means to:
• i) receive input of said first current and said second current from said detecting means,
• ii) determine the difference between said first current and said second current, and
• iii) if said current approaches a predetermined limit, then reduce the power supplied by said power supply means to said heating element so as to alter the current in said heating element to retreat from said predetermined limit and prevent occurrence of said conduit and said heating element overheating, then
• iv) after a predetermined time increase said power supplied by said power supply means to said heating element.