"US 2008/0142019 discloses a high flow therapy system including a non sealing respiratory interface with a sensor disposed near it. The system also includes a humidification chamber to humidify gases and a heater plate to heat the contents of the humidification chamber. The system includes a microprocessor to control the heater plate and measure the pressure of gases delivered. The document discloses monitoring temperature and power data of the heater plate to determine the status of the water level in the humidity chamber and can trigger automatic refill of the chamber.
"US 2002/0112725 discloses a breathing assistance apparatus for delivering humidified gases to a patient. The system includes a humidification chamber with a heater plate and a microprocessor to control the heating of the heater plate. The document discloses a method of determining the amount of power required to heat the contents of the humidifier to the appropriate temperature such that the gases are humidified to their correct level.
"US 2004/0079370 discloses a flow probe for use in a humidification system. The probe provides temperature and flow rate sensing. The document discloses a 'water out alarm' that warns a user when the level of water within the humidification chamber is too low. The system calculates thermal conductivity based on the heater plate power requirement, heater plate temperature and chamber temperature. The controller compares this calculated thermal conductivity with a threshold value. If the threshold value is greater than the thermal conductivity then the level of water is too low.
"In this specification where reference has been made to patent specifications, other external documents, or other sources of information, this is generally for the purpose of providing a context for discussing the features of the invention. Unless specifically stated otherwise, reference to such external documents is not to be construed as an admission that such documents, or such sources of information, in any jurisdiction, are prior art, or form part of the common general knowledge in the art."
As a supplement to the background information on this patent application, VerticalNews correspondents also obtained the inventors' summary information for this patent application: "It is an object of the invention to provide a method of control that may go some way to overcome or to at least provide the public with a useful alternative.
"Accordingly in a first aspect the invention may be said to broadly consist of a method of determining the water level in a humidifier chamber within a humidified gases delivery system, said method comprising the steps of: delivering power to a heater used to heat the contents of the chamber, determining a temperature increase over a time period while the power is delivered, determining a level of water within the chamber based the delivered power, the temperature increase and the time period.
"Preferably the level of water within the chamber is determined based on the rate of temperature increase and the delivered power.
"Preferably the level of water within the chamber is determined from a look up table, the look up table storing values relating the temperature change over a set time period, for a given power with the level of water within the chamber.
"Alternatively the level of water within the chamber is determined by using an equation for heat energy into a substance and rearranging the equation to solve for the mass.
Most Popular Stories
- Hezbollah Chief's Assassination Claimed by Sunni Group
- Allstate Seeks to Invest in Minority Firms
- SpaceX's Satellite Launch Is 'Game-Changer'
- U.S. Growth Stayed Steady During Shutdown, Fed Says
- Newtown Massacre Heard on 911 Recordings
- Latin Music Conference Turns 25
- Climate Change Early Warning System Urged
- Guardian Pressured to Stop NSA Stories: Editor
- New Home Sales Shoot up 25 Percent in October
- Reid Confident Congress to Pass Immigration Bill