NZ767507B2

NZ767507B2 - A Medical Humidifier

Info

Publication number: NZ767507B2
Application number: NZ767507A
Authority: NZ
Inventors: Dmitri Anatolievich Doudkine; Roger Mervyn Lloyd Foote; Matthew Rolf Harrington; Ronald James Huby; Zhuo Ran Tang; Quangang Yang
Original assignee: ResMed Pty Ltd
Priority date: 2014-03-13
Filing date: 2014-09-11
Publication date: 2022-06-28

Abstract

method for controlling a location and/or a rate of foreign matter build-up on a humidifier wick (5230) of a humidifier (5000), the humidifier including the humidifier wick, a heating element (5220) to apply heat to the humidifier wick, a water delivery mechanism to deliver water to the humidifier wick, and a controller configured to receive one more signals and/or generate one or more signals, the humidifier wick being configured to retain a volume of water. The method includes controlling a location and/or a pattern of a water boundary on the humidifier wick of the humidifier by varying, with the controller, at least one of: a heat output from the heating element onto the humidifier wick; a water flow rate from the water delivery mechanism onto the humidifier wick; and a water distribution pattern within the humidifier wick by adjusting the heat output from the heating element and/or the water flow rate from the water delivery. Controlling the location and/or the pattern of the water boundary causes foreign matter to build up at a predetermined region of the humidifier wick based on the location and/or the pattern of the water boundary. wick, and a controller configured to receive one more signals and/or generate one or more signals, the humidifier wick being configured to retain a volume of water. The method includes controlling a location and/or a pattern of a water boundary on the humidifier wick of the humidifier by varying, with the controller, at least one of: a heat output from the heating element onto the humidifier wick; a water flow rate from the water delivery mechanism onto the humidifier wick; and a water distribution pattern within the humidifier wick by adjusting the heat output from the heating element and/or the water flow rate from the water delivery. Controlling the location and/or the pattern of the water boundary causes foreign matter to build up at a predetermined region of the humidifier wick based on the location and/or the pattern of the water boundary.

Description

DIV4 A MEDICAL HUMIDIFIER 1 CROSS-REFERENCE TO RELATED APPLICATIONS Not applicable 2 BACKGROUND OF THE TECHNOLOGY 2.1 FIELD OF THE TECHNOLOGY The present technology relates to one or more of the detection, diagnosis, treatment, prevention and amelioration of respiratory-related disorders. In particular, the present technology relates to medical s or tus, and their use. 2.2 DESCRIPTION OF THE RELATED ART 2.2.1 Human Respiratory System The respiratory system of the body tates gas exchange. The nose and mouth form the entrance to the airways of a patient.

The s include a series of branching tubes, which become narrower, shorter and more numerous as they penetrate deeper into the lung. The prime function of the lung is gas exchange, allowing oxygen to move from the air into the venous blood and carbon dioxide to move out. The trachea divides into right and left main bronchi, which further divide eventually into terminal ioles. The bronchi make up the conducting airways, and do not take part in gas exchange. Further divisions of the airways lead to the respiratory bronchioles, and eventually to the i. The alveolated region of the lung is where the gas exchange takes place, and is ed to as the respiratory zone. See "Respiratory Physiology", by John B. West, Lippincott Williams & Wilkins, 9th edition hed 2011.

A range of respiratory disorders exist.

Obstructive Sleep Apnea (OSA), a form of Sleep Disordered Breathing (SDB), is characterized by occlusion or obstruction of the upper air passage during sleep. It results from a ation of an abnormally small upper airway and the normal loss of muscle tone in the region of the tongue, soft palate and posterior 505809DIV4 oropharyngeal wall during sleep. The condition causes the affected patient to stop breathing for periods typically of 30 to 120 seconds duration, sometimes 200 to 300 times per night. It often causes excessive daytime somnolence, and it may cause cardiovascular disease and brain damage. The syndrome is a common disorder, particularly in middle aged overweight males, although a person affected may have no awareness of the problem. See US Patent 4,944,310 van).

-Stokes Respiration (CSR) is a er of a t's respiratory controller in which there are rhythmic alternating s of waxing and waning ventilation, causing repetitive de-oxygenation and re-oxygenation of the arterial blood. It is possible that CSR is harmful because of the repetitive hypoxia. In some patients CSR is associated with repetitive arousal from sleep, which causes severe sleep disruption, sed sympathetic activity, and increased afterload. See US Patent 6,532,959 on-Jones).

Obesity Hyperventilation Syndrome (OHS) is defined as the combination of severe obesity and awake chronic hypercapnia, in the e of other known causes for hypoventilation. Symptoms include dyspnea, morning headache and excessive daytime ness.

Chronic Obstructive ary Disease (COPD) encompasses any of a group of lower airway diseases that have certain characteristics in common. These include increased resistance to air nt, extended expiratory phase of respiration, and loss of the normal elasticity of the lung. Examples of COPD are emphysema and chronic bronchitis. COPD is caused by chronic tobacco g (primary risk factor), occupational exposures, air pollution and genetic factors.

Symptoms include: dyspnea on exertion, chronic cough and sputum tion.

Neuromuscular Disease (NMD) is a broad term that encompasses many diseases and ailments that impair the functioning of the muscles either directly via intrinsic muscle pathology, or indirectly via nerve pathology. Some NMD patients are characterised by progressive muscular impairment leading to loss of ambulation, being wheelchair-bound, wing difficulties, respiratory muscle weakness and, eventually, death from respiratory failure. Neuromuscular disorders can be divided into rapidly progressive and slowly progressive: (i) Rapidly progressive disorders: 505809DIV4 Characterised by muscle impairment that worsens over months and results in death within a few years (e.g. Amyotrophic lateral sclerosis (ALS) and Duchenne muscular dystrophy (DMD) in teenagers); (ii) Variable or slowly progressive disorders: Characterised by muscle impairment that worsens over years and only mildly reduces life expectancy (e.g. Limb girdle, Facioscapulohumeral and Myotonic muscular dystrophy). Symptoms of respiratory failure in NMD include: increasing generalised weakness, dysphagia, dyspnea on exertion and at rest, fatigue, sleepiness, morning headache, and difficulties with concentration and mood s.

Chest wall disorders are a group of ic ities that result in inefficient coupling between the respiratory muscles and the ic cage. The disorders are usually characterised by a restrictive defect and share the potential of long term apnic respiratory failure. Scoliosis and/or kyphoscoliosis may cause severe respiratory e. ms of respiratory failure include: dyspnea on exertion, peripheral oedema, orthopnea, repeated chest infections, morning headaches, fatigue, poor sleep quality and loss of appetite.

Otherwise healthy individuals may take advantage of systems and devices to prevent respiratory disorders from arising. 2.2.2 Therapy Nasal Continuous Positive Airway Pressure (CPAP) therapy has been used to treat Obstructive Sleep Apnea (OSA). The hypothesis is that uous positive airway pressure acts as a pneumatic splint and may prevent upper airway ion by pushing the soft palate and tongue forward and away from the posterior oropharyngeal wall.

Non-invasive ventilation (NIV) provides ventilatory support to a patient h the upper airways to assist the patient in taking a full breath and/or maintain adequate oxygen levels in the body by doing some or all of the work of breathing.

The ventilatory support is provided via a patient ace. NIV has been used to treat CSR, OHS, COPD, MD and Chest Wall disorders. 505809DIV4 Invasive ventilation (IV) provides ventilatory support to patients that are no longer able to ively breathe themselves and is provided using a ostomy tube.

Ventilators may control the timing and pressure of breaths pumped into the patient and monitor the breaths taken by the patient. The methods of control and monitoring patients typically include volume-cycled and pressure-cycled methods.

The volume-cycled s may include among , Pressure-Regulated Volume l (PRVC), Volume Ventilation (VV), and Volume Controlled Continuous Mandatory Ventilation (VC-CMV) techniques. The pressure-cycled methods may involve, among others, Assist Control (AC), Synchronized Intermittent Mandatory Ventilation (SIMV), Controlled ical Ventilation (CMV), Pressure t Ventilation (PSV), uous Positive Airway Pressure (CPAP), or Positive End Expiratory Pressure (PEEP) techniques. 2.2.3 Systems A system may comprise an RPT device, an air circuit, a humidifier, a patient interface, and data management. 2.2.4 Patient Interface A patient interface may be used to interface respiratory equipment to its user, for example by providing a flow of air. The flow of air may be provided via a mask to the nose and/or mouth, a tube to the mouth or a tracheostomy tube to the trachea of the user. Depending upon the therapy to be applied, the t interface may form a seal, e.g. with a face region of the patient, to tate the delivery of gas at a pressure at sufficient variance with ambient pressure to effect therapy, e.g. a ve pressure of about 10cmH2O. For other forms of therapy, such as the delivery of oxygen, the patient interface may not include a seal sufficient to facilitate delivery to the airways of a supply of gas at a positive pressure of about 10cmH2O.

The design of a patient interface presents a number of nges. The face has a complex three-dimensional shape. The size and shape of noses varies considerably between individuals. Since the head includes bone, cartilage and soft tissue, different regions of the face d differently to mechanical forces. The jaw 505809DIV4 or mandible may move relative to other bones of the skull. The whole head may move during the course of a period of respiratory therapy.

As a consequence of these challenges, some masks suffer from being one or more of obtrusive, aesthetically undesirable, costly, poorly fitting, difficult to use, and uncomfortable especially when worn for long periods of time or when a patient is unfamiliar with a system. For e, masks designed solely for aviators, mask designed as part of personal protection equipment (e.g. filter masks), SCUBA masks, or for the administration of anaesthetics may be tolerable for their original application, but nevertheless be undesirably uncomfortable to be worn for extended periods of time, e.g. several hours. This is even more so if the mask is to be worn during sleep.

Nasal CPAP therapy is highly effective to treat certain respiratory disorders, provided patients comply with therapy. If a mask is uncomfortable, or difficult to use a patient may not comply with therapy. Since it is often recommended that a patient regularly wash their mask, if a mask is difficult to clean (e.g. difficult to assemble or disassemble), patients may not clean their mask and this may impact on patient ance.

While a mask for other applications (e.g. aviators) may not be suitable for use in ng sleep disordered breathing, a mask ed for use in treating sleep disordered breathing may be suitable for other applications.

For these s, masks for delivery of nasal CPAP during sleep form a distinct field. 2.2.5 atory Pressure Therapy (RPT) Device Examples of RPT s include ResMed’s S9 AutoSetTM PAP device and ResMed’s Stellar™ 150 ventilator. RPT devices typically se a re generator, such as a motor-driven blower or a compressed gas reservoir, and are configured to supply a flow of air to the airway of a patient. In some cases, the flow of air may be supplied to the airway of the patient at positive pressure. The outlet of the RPT device is connected via an air t to a patient interface such as those 505809DIV4 described above. In some cases, RPT devices have been known to be referred to as flow tors.

RPT devices typically include a pressure generator, an inlet filter, a patient ace, an air circuit connecting the pressure generator to the patient interface, various sensors and a rocessor-based controller. The patient interface may include a mask or a tracheostomy tube as described above. The pressure generator may e a servo-controlled motor, volute and an impeller. In some cases a brake for the motor may be implemented to more rapidly reduce the speed of the blower so as to overcome the inertia of the motor and impeller. The braking can permit the blower to more rapidly achieve a lower pressure condition in time for synchronization with exhalation despite the inertia. In some cases the pressure generator may also include a valve capable of discharging generated air to here as a means for altering the pressure delivered to the patient as an alternative to motor speed l. The sensors may e, amongst other things, motor speed, air flow rate and outlet pressure, such as with a pressure transducer or the like. The controller may include data storage capacity with or without integrated data retrieval and display functions.

Table of noise output levels of prior devices (one specimen only, measured using test method specified in ISO3744 in CPAP mode at 10cmH2O).

Device name A-weighted sound power Year (approx.) level dB(A) C-Series Tango 31.9 2007 C-Series Tango with Humidifier 33.1 2007 S8 Escape II 30.5 2005 S8 Escape II with H4i Humidifier 31.1 2005 S9 AutoSet 26.5 2010 S9 AutoSet with H5i Humidifier 28.6 2010 2.2.6 Humidifier Delivery of a flow of air without fication may cause drying of airways. l humidifiers are used to increase absolute humidity and/or temperature of the flow of air in relation to ambient air when ed, typically 505809DIV4 where the patient may be asleep or resting (e.g. at a hospital). As a result, a medical humidifier is ably small for bedside placement, and it is preferably configured to only humidify and/or heat the flow of air delivered to the patient without humidifying and/or heating the patient’s ndings. Room-based systems (e.g. a sauna, an air conditioner, an evaporative cooler), for example, may also fy air that is breathed in by the patient, however they would also humidify and/or heat the entire room, which may cause discomfort to the occupants.

The use of a humidifier with a pressure generator or RPT device and the patient interface produces humidified gas that zes drying of the nasal mucosa and increases patient airway comfort. In addition in cooler climates, warm air applied generally to the face area in and about the patient interface is more comfortable than cold air.

Respiratory humidifiers are available in many forms and may: be a standalone device that is coupled to an RPT device via an air conduit, is integrated with the RPT device, or be configured to be ly coupled to the nt RPT device. While known e humidifiers can provide some relief, generally a heated humidifier may be used to provide sufficient humidity and temperature to the air so that the patient will be comfortable. Humidifiers typically comprise a water reservoir or tub having a capacity of l hundred milliliters (ml), a heating element for heating the water in the reservoir, a control to enable the level of humidification to be varied, a gas inlet to receive gas from the RPT device, and a gas outlet adapted to be connected to an air circuit that delivers the fied gas to the patient interface.

Heated passover humidification is one common form of humidification used with an RPT device. In such humidifiers the heating t may be incorporated in a heater plate which sits under, and is in thermal contact with, the water tub. Thus, heat is transferred from the heater plate to the water reservoir ily by conduction. The air flow from the RPT device passes over the heated water in the water tub resulting in water vapour being taken up by the air flow. The ResMed H4i™ and H5i™ Humidifiers are examples of such heated passover humidifiers that are used in combination with ResMed S8 and S9 RPT devices respectively. 505809DIV4 Other humidifiers may also be used such as a bubble or diffuser humidifier or a jet fier. In a bubble or diffuser humidifier the air is conducted below the surface of the water and allowed to bubble back to the top. A jet humidifier produces an aerosol of water and baffles or filters may be used so that the les are either removed or evaporated before leaving the humidifier.

An alternative form of humidification is provided by the ResMed HumiCare™ D900 humidifier that uses a CounterStream™ technology that directs the air flow over a large surface area in a first ion whilst supplying heated water to the large surface area in a second opposite direction. The ResMed re™ D900 humidifier may be used with a range of invasive and non-invasive ventilators. 3 BRIEF SUMMARY OF THE TECHNOLOGY The present technology is directed towards providing medical devices used in the diagnosis, amelioration, treatment, or prevention of respiratory ers having one or more of improved comfort, cost, efficacy, ease of use and manufacturability.

A first aspect of the present technology s to apparatus used in the sis, amelioration, treatment or prevention of a respiratory disorder.

Another aspect of the present technology relates to methods used in the diagnosis, amelioration, treatment or prevention of a respiratory disorder.

Another aspect of the present technology s to a humidifier increasing an absolute humidity of a flow of air to be delivered to a patient’s airways, the humidifier comprising a water oir configured to retain a first volume of water, a humidifier chamber comprising an air inlet for receiving the flow of air, a water retention feature configured to retain a second volume of water, a heating element and an air outlet for ring the flow of air, and a water ry mechanism configured to deliver a flow of water from the water reservoir to the water retention e wherein the heating element is configured to heat the water retention feature to vaporise the second volume of water to add absolute humidity to the flow of air.

A further aspect of the present technology relates to a humidifier wherein the water retention feature comprises a wick. 505809DIV4 A r aspect of the present technology relates to a humidifier wherein the water retention feature is coupled to a carrier.

A further aspect of the t technology relates to a carrier further comprising a grip surface.

A further aspect of the present technology relates to a humidifier wherein the humidifier further comprises an air flow baffle.

A further aspect of the present technology s to a humidifier wherein the air flow baffle is coupled to the water retention feature.

A further aspect of the present technology relates to a humidifier wherein the air flow baffle forces the air flow to travel along a helical path.

A r aspect of the present technology relates to a fier wherein the heating element comprises a resistive electrical track.

A further aspect of the present logy relates to a humidifier n the resistive ical track is disposed on a circuit board.

A further aspect of the present technology relates to a fier wherein the circuit board is a flexible circuit board.

A further aspect of the present technology relates to a humidifier wherein the resistive electrical track comprises one or more strands of resistive wire.

A r aspect of the present technology relates to a humidifier wherein the one or more strands of resistive wire forms a plurality of loops around a surface of the humidifier chamber.

A r aspect of the present technology relates to a heating element further comprising an adhesive for securing the plurality of loops.

A further aspect of the present technology relates to a humidifier further sing one or more temperature sensors configured to measure one or more temperatures at the water retention feature. 505809DIV4 Of course, portions of the aspects may form sub-aspects of the present technology. Also, various ones of the sub-aspects and/or aspects may be combined in various manners and also constitute additional aspects or sub-aspects of the present logy.

Other features of the technology will be apparent from consideration of the information contained in the following detailed description, abstract, drawings and claims. 4 BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS The present technology is illustrated by way of example, and not by way of limitation, in the figures of the accompanying drawings, in which like reference numerals refer to similar elements including: 4.1 TREATMENT S Fig. 1a shows a system ing a patient 1000 wearing a patient interface 3000, in the form of a nasal pillows, receives a supply of air at positive pressure from an RPT device 4000. Air from the RPT device is humidified in a humidifier 5000, and passes along an air circuit 4170 to the t 1000, a bed partner 1100 is also shown.

Fig. 1b shows a system including a patient 1000 g a patient interface 3000, in the form of a nasal mask, receives a supply of air at positive pressure from an RPT device 4000. Air from the RPT device is humidified in a humidifier 5000, and passes along an air circuit 4170 to the patient 1000.

Fig. 1c shows a system including a patient 1000 g a t interface 3000, in the form of a ace mask, receives a supply of air at positive pressure from an RPT device 4000. Air from the RPT device is humidified in a humidifier 5000, and passes along an air circuit 4170 to the patient 1000. 505809DIV4 4.2 THERAPY 4.2.1 Respiratory system Fig. 2a shows an overview of a human respiratory system including the nasal and oral cavities, the larynx, vocal folds, oesophagus, trachea, bronchus, lung, alveolar sacs, heart and diaphragm.

Fig. 2b shows a view of a human upper airway including the nasal cavity, nasal bone, l nasal cartilage, greater alar cartilage, nostril, lip superior, lip inferior, larynx, hard palate, soft , oropharynx, tongue, epiglottis, vocal folds, oesophagus and a. 4.3 T INTERFACE Fig. 3 shows a patient interface 3000 in the form of a nasal mask in accordance with one form of the t technology. 4.4 RPT DEVICE Fig. 4a shows an ed view of an RPT device 4000 in accordance with one form of the present technology.

Fig. 4b shows a schematic diagram of the pneumatic circuit of an RPT device 4000 in accordance with one form of the present technology. The directions of upstream and ream are indicated.

Fig. 4c shows a schematic diagram of the electrical components of an RPT device 4000 in accordance with one aspect of the present technology. 4.5 BREATHING WAVEFORMS Fig. 5 shows a model typical breath waveform of a person while sleeping.

The horizontal axis is time, and the vertical axis is respiratory flow. While the values may vary, a typical breath may have the following approximate values: tidal volume, Vt, 0.5L, inhalation time, Ti, 1.6s, peak inspiratory flow, Qpeak, 0.4 L/s, tion time, Te, 2.4s, peak expiratory flow, Qpeak, -0.5 L/s. The total duration of the breath, Ttot, is about 4s. The person typically breathes at a rate of about 15 breaths per minute 505809DIV4 (BPM), with Ventilation, Vent, about 7.5 L/minute. A typical duty cycle, the ratio of Ti to Ttot is about 40%. 4.6 HUMIDIFIER Fig. 6 shows one form of a prior art humidifier.

Fig. 7 shows a perspective view of a humidifier 5000 according to one aspect of the present technology.

Fig. 8 shows a schematic view of the humidifier of Fig. 7 further comprising a water delivery mechanism 5150 and a water oir 5110.

Fig. 9a shows a cross-section view in elevation of the humidifier of Fig. 7.

Fig. 9b shows a section view in elevation of a humidifier 5000 according to an aspect of the present technology.

Fig. 10 shows an exploded perspective view of a portion of the humidifier 5000 of Fig. 7 g a humidifier wick 5230 and a wick frame 5232.

Fig. 11 shows a perspective view of one form of a heating t 5220 for a fier according to the present technology, the heating element comprising multiple heating zones.

Fig. 12 shows a cross-section view in elevation of a fier comprising a multiple layered wick 5230 according to an aspect of the present technology.

Fig. 13 shows a perspective view of a humidifier wick 5230 according to an aspect of the present technology, the humidifier wick comprising a corrugated inner surface.

Fig. 14 shows a cross-section view in ion of a humidifier 5000 showing a dry region 5230_D and a wet region 5230_W of the humidifier wick 5230 ing to an aspect of the present technology.

Fig. 15 shows a cross-section view in elevation of a humidifier 5000 including an arrangement of multiple humidifier transducers according to an aspect of the present technology. 505809DIV4 Fig. 16 shows a cross-section view in elevation of a fier including a ature sensor 5514_5 according to a further aspect of the present technology.

Fig. 17 shows an example of a relationship between a power output of a g element and the humidity added to the flow of air by the humidifier.

Fig. 18 shows an example of a relationship between a temperature of a heating element and the humidity added to the flow of air by the humidifier.

Fig. 19 shows an example of a relationship between a power output of a heating element and the ty added to the flow of air by the humidifier at various air flow rates.

Fig. 20 shows a perspective view of a humidifier 5000 according to one aspect of the present technology, n the heating element 5220 comprises resistive wires.

Fig. 21 shows a representation of example humidifier algorithms 5600 according to one aspect of the present technology.

Fig. 22 shows a art of an e algorithm 5610A of a wick condition determination algorithm according to one aspect of the present technology.

Fig. 23 shows a flowchart of another example algorithm 5610B of a wick condition ination algorithm according to one aspect of the present technology.

Fig. 24 shows a flowchart of another example algorithm 5610C of a wick condition determination algorithm according to one aspect of the present logy.

Fig. 25 shows a flowchart of an example algorithm 5620A of a plausibility check algorithm according to one aspect of the present technology.

DETAILED PTION OF EXAMPLES OF THE TECHNOLOGY Before the present technology is described in further detail, it is to be understood that the technology is not limited to the particular examples described herein, which may vary. It is also to be understood that the terminology used in this 505809DIV4 sure is for the purpose of describing only the particular examples discussed herein, and is not intended to be limiting. .1 TREATMENT SYSTEMS In one form, the present technology comprises a system for treating a respiratory disorder. For e, a system may comprise an RPT device 4000, a humidifier 5000, an air circuit 4170 and a patient interface 3000. .2 THERAPY In one form, the t logy comprises a method for treating a respiratory disorder comprising the step of applying positive pressure to the entrance of the airways of a patient 1000. .2.1 Nasal CPAP for OSA In one form, the present technology comprises a method of treating Obstructive Sleep Apnea in a patient by applying nasal continuous positive airway pressure to the patient.

In certain embodiments of the present technology, a supply of air at positive pressure is provided to the nasal passages of the patient via one or both nares. .3 T INTERFACE 3000 A non-invasive patient interface 3000 in accordance with one aspect of the present technology ses the following functional aspects (e.g. as shown in Fig. 3): a seal-forming structure 3100, a plenum chamber 3200, a positioning and stabilising structure 3300 and a connection port 3600 for connection to air circuit 4170. The patient interface 3000 may further comprise a forehead support 3700 in some forms such as that shown in Fig. 3. In some forms a functional aspect may be provided by one or more physical components. In some forms, one physical component may e one or more functional aspects. In use the seal-forming structure 3100 is arranged to nd an entrance to the airways of the patient so as to facilitate the supply of air at positive pressure to the airways. 505809DIV4 .4 RPT device 4000 A preferred RPT device 4000 in accordance with one aspect of the present technology comprises mechanical and pneumatic components 4100, electrical components 4200 and is mmed to execute one or more algorithms. The RPT device (e.g. as shown in Fig. 4a) preferably has an external housing 4010, for e formed in two parts, an upper portion 4012 and a lower n 4014. Furthermore the external housing 4010 may e one or more panel(s) 4015. Preferably the RPT device 4000 comprises a s 4016 that ts one or more internal components of the RPT device 4000. In one form a pneumatic block 4020 is supported by, or formed as part of the chassis 4016. The RPT device 4000 may e a handle 4018.

The pneumatic path of the RPT device 4000 (e.g. as shown in Fig. 4b) may comprise an inlet air filter 4112, an inlet muffler 4122, a pressure device 4140 capable of supplying air at positive pressure (preferably a blower 4142), and an outlet muffler 4124. One or more transducers 4270, such as pressure sensors 4272 and flow sensors 4274, may be included in, or coupled with, the pneumatic path.

The pneumatic block 4020 may comprise a portion of the pneumatic path that is located within the RPT device 4000.

The RPT device 4000 may comprise electrical components 4200 such as an electrical power supply 4210, one or more input devices 4220, a central controller 4230, a therapy device controller 4240, a pressure device 4140, one or more protection ts 4250, memory 4260, transducers 4270 (for example one or more of a flow sensor 4274, a pressure sensor 4272 and a speed sensor 4276), data communication interface 4280 and one or more output devices 4290 (for example a display 4294 and display driver 4292). Electrical components 4200 may be mounted on a single Printed Circuit Board ly (PCBA) 4202. In an alternative form, the RPT device 4000 may include more than one PCBA 4202.

The central controller 4230 of the RPT device 4000 may be programmed to execute one or more algorithm modules, such as a pre-processing module, a therapy engine module, a pressure control module, and a fault condition module. 505809DIV4 .4.1 RPT device mechanical & pneumatic components 4100 1 Air filter(s) 4110 An RPT device in accordance with one form of the present technology may include an air filter 4110, or a plurality of air filters 4110.

For example, the air filter 4110 may be located at the beginning of the pneumatic path upstream of a blower 4142 as an inlet air filter 4112, or at the outlet of the RPT device 4000 as an outlet air filter 4114. See Fig. 4b. .4.1.2 r(s) 4120 In one form of the present technology, an inlet muffler 4122 is located in the pneumatic path, such as upstream of a pressure device 4140 or ream of the pressure device 4140. See Fig. 4b. .4.1.3 re device 4140 In a preferred form of the present logy, a pressure device 4140 for producing a flow of air at ve pressure is a controllable blower 4142. For example the blower may include a brushless DC motor 4144 with one or more impellers housed in a volute. The blower may be preferably capable of delivering a supply of air, for example about 120 litres/minute, at a positive pressure in a range from about 4 cmH2O to about 20 cmH2O, or in other forms up to about 30 cmH2O.

The blower may include a blower as described in any one of the ing patents or patent applications the contents of which are incorporated herein in their entirety: U.S. patent number 7,866,944; U.S. patent number 8,638,014; U.S. Patent number 8,636,479; and PCT patent application publication number .4.1.4 Anti-spill back valve 4160 In one form of the present technology, an anti-spill back valve is located between the humidifier 5000 and the pneumatic block 4020. The anti-spill back valve is constructed and arranged to reduce the risk that water will flow upstream from the humidifier 5000, for example to the motor 4144. 505809DIV4 .4.1.5 Air circuit 4170 An air circuit 4170 in accordance with an aspect of the present technology is constructed and arranged to allow a flow of air between the pneumatic block 4020 and the patient interface 3000. In some forms, the air circuit 4170 may comprise a heating element configured to heat the flow of air travelling through the air circuit 4170. 6 Oxygen delivery 4180 In one form of the present technology, supplemental oxygen 4180 is delivered to one or more points in the pneumatic path, such as upstream of the pneumatic block 4020, to the air circuit 4170 or to the patient interface 3000. .4.2 RPT device electrical ents 4200 .4.2.1 Power supply 4210 In one form of the present technology power supply 4210 is internal of the external housing 4010 of the RPT device 4000. In r form of the present technology, power supply 4210 is external of the al housing 4010 of the RPT device 4000.

In one form of the present logy power supply 4210 provides electrical power to the RPT device 4000 only. In another form of the present logy, power supply 4210 provides electrical power to both RPT device 4000 and humidifier 5000. .4.2.2 Input devices 4220 In one form of the t technology, an RPT device 4000 includes one or more input devices 4220 in the form of buttons, switches or dials to allow a person to interact with the device. The s, switches or dials may be physical devices, or software devices accessible via a touch screen. The buttons, switches or dials may, in one form, be physically connected to the external housing 4010, or may, in another form, be in wireless communication with a receiver that is in electrical connection to the central controller 4230. 505809DIV4 In one form the input device 4220 may be constructed and arranged to allow a person to select a value and/or a menu option. .4.2.3 Central controller 4230 In one form of the present logy, the central ller 4230 is a dedicated electronic t configured to receive input signal(s) from the input device 4220, and to provide output signal(s) to the output device 4290 and / or the therapy device controller 4240.

In one form, the central controller 4230 is an application-specific integrated circuit. The central controller 4230 may comprise discrete electronic components.

In another form of the present technology, the central controller 4230 is a processor le to control an RPT device 4000 such as an x86 INTEL processor.

A processor le to control an RPT device 4000 in accordance with another form of the present technology includes a processor based on ARM Cortex-M sor from ARM Holdings. For example, an STM32 series microcontroller from ST MICROELECTRONICS may be used.

Another processor suitable to control an RPT device 4000 in accordance with a r alternative form of the present technology includes a member selected from the family ARM9-based 32-bit RISC CPUs. For example, an STR9 series microcontroller from ST LECTRONICS may be used.

In certain alternative forms of the present technology, a 16-bit RISC CPU may be used as the processor for the RPT device 4000. For example a processor from the MSP430 family of microcontrollers, manufactured by TEXAS INSTRUMENTS, may be used.

The central ller 4230 is configured to receive input signal(s), such as input signals from one or more transducers 4270, one or more humidifier transducers and one or more input devices 4220. 505809DIV4 The central controller 4230 is configured to provide output signal(s) such as to one or more of an output device 4290, a therapy device controller 4240, a data communication interface 4280 and humidifier controller 5550.

In some forms of the present technology, the central controller 4230, or multiple such central controllers, is configured to implement the one or more methodologies described herein such as the one or more algorithms expressed as computer programs stored in a non-transitory computer readable storage , such as memory 4260. In some cases, as previously discussed, such processor(s) may be ated with an RPT device 4000. However, in some forms of the present technology the processor(s) may be implemented discretely from the pressure generation components of the RPT device 4000, such as for e of ming any of the ologies described herein without directly controlling delivery of a respiratory treatment. For example, such a processor may perform any of the methodologies described herein for purposes of ining control settings for an RPT device by analysis of stored data such as from any of the sensors described herein. .4.2.4 Clock 4232 ably RPT device 4000 includes a clock 4232 that is ted to a central controller 4230. .4.2.5 Therapy device controller 4240 In one form of the present technology, therapy device ller 4240 is a pressure control module that forms part of the algorithms executed by the central controller 4230.

In one form of the present technology, therapy device controller 4240 is a dedicated motor control integrated circuit. For example, in one form a MC33035 brushless DC motor controller, manufactured by ONSEMI is used. .4.2.6 Protection circuits 4250 ably an RPT device 4000 in accordance with the present logy comprises one or more protection circuits 4250. 505809DIV4 One form of tion circuit 4250 in accordance with the present technology is an electrical protection circuit.

One form of protection circuit 4250 in accordance with the present technology is a temperature and/or pressure safety circuit. .4.2.7 Memory 4260 In accordance with one form of the present logy the RPT device 4000 includes memory 4260, preferably non-volatile memory. In some forms, memory 4260 may include battery powered static RAM. In some forms, memory 4260 may include volatile RAM.

Preferably memory 4260 is d on PCBA 4202. Memory 4260 may be in the form of EEPROM, or NAND flash.

Additionally or alternatively, RPT device 4000 includes removable form of memory 4260, for example a memory card made in accordance with the Secure Digital (SD) standard.

In one form of the present logy, the memory 4260 acts as a nontransitory computer readable storage medium on which is stored computer program instructions expressing the one or more methodologies described herein, such as the one or more algorithms. .4.2.8 Transducers 4270 Transducers may be al or external of the RPT device 4000. External transducers may be located for example on or form part of the air circuit 4170 humidifier 5000 and/or the patient interface 3000. External transducers 4270 may be in the form of ntact sensors such as a r radar movement sensor that transmit or transfer data to the RPT device.

In one form of the present technology, one or more transducers 4270 may be constructed and ed to measure properties of the air, such as at one or more points in the pneumatic path or of ambient air. In another form, one or more transducers 4270 may be configured to e properties of the RPT device 4000 such as motor speed and/or motor current. 505809DIV4 .4.2.8.1 Flow 4274 A flow ucer 4274 in accordance with the present technology may be based on a differential pressure transducer, for example, an SDP600 Series ential pressure transducer from SENSIRION. The differential pressure transducer is in fluid communication with the pneumatic circuit, with one of each of the pressure transducers connected to respective first and second points in a flow restricting element.

In use, a signal representing total flow Qt from the flow transducer 4274 is received by the central controller 4230. .4.2.8.2 Pressure 4272 A pressure transducer 4272 in accordance with the present logy is located in fluid communication with the pneumatic circuit. An example of a suitable pressure transducer is a sensor from the HONEYWELL ASDX series. An alternative suitable pressure transducer is a sensor from the NPA Series from GENERAL ELECTRIC.

In use, a signal from the re transducer 4272 is received by the central controller 4230. In one form, the signal from the pressure transducer 4272 may be filtered prior to being received by the central ller 4230. .4.2.8.3 Motor speed 4276 In one form of the present technology a motor speed signal is ted. A motor speed signal is preferably provided by y device controller 4240. Motor speed may, for example, be generated by a speed sensor, such as a Hall effect sensor. .4.2.9 Data communication interface 4280 In one preferred form of the present technology, a data communication interface 4280 is provided, and is connected to central controller 4230. Data communication interface 4280 is preferably connectable to remote external ication network 4282. Data communication interface 4280 is preferably connectable to local external communication network 4284. ably remote external communication k 4282 is connectable to remote external device 4286. 505809DIV4 Preferably local al communication network 4284 is connectable to local external device 4288.

In one form, data communication interface 4280 is part of central controller 4230. In another form, data communication ace 4280 is an integrated circuit that is te from central controller 4230.

In one form, remote external communication k 4282 is the Internet.

The data communication ace 4280 may use wired communication (e.g. via Ethernet, or optical fibre) or a wireless protocol to connect to the Internet.

In one form, local al communication network 4284 utilises one or more communication standards, such as Bluetooth, or a consumer infrared ol.

In one form, remote external device 4286 is one or more computers, for example a cluster of networked computers. In one form, remote external device 4286 may be virtual computers, rather than physical computers. In either case, such remote external device 4286 may be accessible to an riately ised person such as a clinician.

Preferably local external device 4288 is a personal computer, mobile phone, tablet or remote control. .4.2.10 Output devices including optional display, alarms 4290 An output device 4290 in accordance with the present technology may take the form of one or more of a visual, audio and haptic unit. A visual display may be a Liquid Crystal Display (LCD) or Light Emitting Diode (LED) display. .4.2.10.1 Display driver 4292 A display driver 4292 receives as an input the characters, symbols, or images intended for display on the display 4294, and converts them to commands that cause the y 4294 to display those characters, symbols, or images. .4.2.10.2 Display 4294 A display 4294 is configured to visually display characters, symbols, or images in response to commands received from the display driver 4292. For example, 505809DIV4 the display 4294 may be an eight-segment display, in which case the display driver 4292 converts each character or symbol, such as the figure "0", to eight logical signals indicating whether the eight respective segments are to be activated to display a particular character or symbol. .5 FIER 5000 .5.1 Humidifier overview In one form of the present logy as shown in Fig. 7, there is provided a fier 5000 for sing a moisture content, or absolute ty, of a flow of air in relation to the t air (air surrounding the patient), before the flow of air is delivered to the ce of the patient’s airways. In one example, the humidifier 5000 may deliver a flow of humidified air at 80 % ve humidity and 27 °C.

Characteristics of prior art humidifiers may include from one or more of: slow response time, long warm-up time, large volume and/or footprint and risk of water spillage. A humidifier 5000 according to the t technology seems to improve upon, or ameliorate, one or more of the above characteristics.

The humidifier 5000 may comprise an air inlet 5002 to receive the flow of air, and an air outlet 5004 to deliver the flow of air with added humidity. .5.2 Humidifier components .5.2.1 Water reservoir 5110 According to one aspect of the present technology, the humidifier 5000 may comprise a water reservoir 5110 as shown in Fig. 8. The water reservoir 5110 may be configured to hold a predetermined, maximum volume of water (or other suitable liquids), which may be used to increase absolute humidity of the flow of air.

In one form, the reservoir 5110 may be configured to hold several hundred millilitres of water, for use during at least the length of the patient’s sleep in a day. However, in other forms, other sizes such as a smaller reservoir for a portable, travel-friendly system or a larger reservoir for a hospital system may be also suitable.

Yet further, a reservoir 5110 may be replaced by, or connected to, a water supply. 505809DIV4 ing to some arrangements, the water reservoir 5110 may comprise, or be coupled to, a water volume detector 5112 by which the amount of water in the reservoir 5110 may be determined. The water volume detector 5112 may determine the volume of water based on one or more of a presence, weight, optical property, ultrasonic property or a head of the water of the reservoir 5110. Any of the mechanisms or s such as those described in the Australian Provisional Patent Application AU 2013904049 may also be suitable for use with the t technology, the entire contents of which is incorporated herewithin by eference.

In some forms, the water reservoir 5110 may be configured to heat the water prior to the water entering the humidification chamber 5200, for example by sing, or being coupled to, a reservoir g element 5221 as shown in Fig. 8. .5.2.2 Water delivery mechanism 5150 According to one aspect of the t technology, the humidifier 5000 may comprise a water delivery mechanism 5150 configured to deliver a flow of water from the water reservoir 5110 to a humidification chamber 5200 (see Fig. 8). The water delivery mechanism 5150 may comprise a water pump 5152 and a water delivery conduit 5154, and may be in fluid communication with a water feed inlet 5206 to deliver the flow of water to the humidification chamber 5200. The water delivery mechanism 5150 in some forms may further comprise a valve (e.g. water check valve 5158) for preventing delivery of water from the reservoir 5110 to the humidification chamber 5200.

Preferably, the humidification chamber 5200 comprises a water retention feature such as a humidifier wick 5230, which receives the flow of water from the water ry mechanism 5150. In some forms, the humidifier 5000 may comprise a ity of water delivery mechanisms 5150 and/or a plurality of water feed inlets 5206 in order to better control a distribution of water in the humidifier wick 5230. In this disclosure, a water flow rate will be taken to mean a rate of flow of water from the water reservoir 5110 to a humidification r 5200 unless explicitly stated otherwise. 505809DIV4 The water flow rate(s) that the humidifier 5000 is configured to provide may vary according to factors such as the configuration of the humidifier 5000 and a range of expected operating conditions such as ambient conditions (e.g. ambient temperature/humidity), humidifier operating parameters (e.g. maximum heat output of the heating element 5220, maximum water capacity of the humidifier wick 5230) and/or therapy conditions (e.g. therapy pressure, air flow rate, t comfort/preference). For example, a change in therapy pressure only may cause a change in the water flow rate, such as due to a response by the humidifier controller 5550, or due to a property of the water delivery mechanism 5150.

In one form, the range of water flow rates able to be provided by the humidifier 5000 may be between 0 ml/min and 2 ml/min, for example between 0 ml/min and 1 ml/min, or between 0 ml/min and 0 ml/min. In one form, the humidifier 5000 may be configured to provide one of a number of discrete water flow rates, for example 0.0 ml/min, 0.2 ml/min, 0.4 ml/min, 0.6 ml/min or 0.8 ml/min where the limits of water flow rates able to be provided are 0.0 ml/min and 0.8 . In other forms, the humidifier 5000 may be configured to e any water flow rate between its limits by providing an analogue l of the flow rate. The water flow rate at a particular time during operation of the humidifier 5000 may then depend on the set of operating conditions at the particular time. For example, a typical value with an air flow of 35 l/min and d added humidity of 15 mg/l requires a water flow of 0.5 ml/min.

A pressure of the flow of air (also known as air pressure) in a respiratory device and its pneumatic path downstream thereof may vary during therapy, for example between 4 and 30 cmH2O. Thus, preferably, the water pump 5152 is configured to deliver a consistent water flow rate across various air pressures in the fier 5000. Preferably (however not necessarily), the water flow rate provided by the water pump 5152 may be independent from (i.e. not be affected by) the air re in the humidifier 5000. Such a water pump 5152 would be advantageous in that the air pressure may be varied ndently of the amount of humidification provided o for improved controllability of the therapy system.

In one form, the water pump 5152 may be a positive displacement type pump, such as one described in Australian ional Patent Application Number 505809DIV4 AU 3277, the entire contents of which is incorporated herewithin by crossreference.

In another form, many other types of pumps such as d pumps, peristaltic pumps, gravity-fed pumps, or pumps utilising blower pressure may be suitable to be used in the water ry mechanism 5150. An elevated water reservoir (not shown) such as a drip bag may also be suitable and act as a pump of sorts to deliver water.

In some forms, where a water flow rate through the water pump 5152 may be affected by the air pressure, the flow rate through the water pump 5152 may be compensated accordingly. For instance as shown in Fig. 8, the water delivery mechanism 5150 may additionally se one or more of a metering mechanism 5156, a water check valve 5158 to measure and/or control the water flow rate through the water pump 5152. Alternatively, the humidifier controller 5550 may be used to compensate for the effects of any changes to the air pressure, by controlling the water pump 5152 according to the air pressure which may be ed by the humidifier controller 5550 as an input. In some forms, the humidifier controller 5550 may be used to compensate for the effects of any changes to the air flow rate (e.g. due to a change in leak), by controlling the water flow rate through the water delivery mechanism 5150.

In another arrangement (not shown), a water pump 5152 may be configured to pump water by utilising a pressure such as that generated by the RPT device 4000. The pressure may then be used to draw water from the water reservoir 5110 into the fication chamber 5200. The water flow rate in such an arrangement may be a function of the air flow rate, and thus the fier 5000 in this ement may further comprise a control valve to regulate the water flow rate.

The humidifier 5000 may in some forms comprise a fault detection mechanism to detect conditions such as blockages in the water delivery mechanism 5150 or a shortage of water in the reservoir 5110, as will be described in further detail below. For example, a blockage in a positive displacement pump may cause its motor to stall, causing the pump to stop. Furthermore, the humidifier 5000 may be configured to detect accumulation of precipitates and/or contamination, such as in the wick 5230, as precipitants or contaminants may adversely affect performance of the humidifier 5000. 505809DIV4 .5.2.3 Humidification chamber 5200 According to one aspect, the humidifier 5000 may comprise a humidification chamber 5200, in which moisture is added to the flow of air, thus increasing the absolute humidity, prior to being delivered to the t 1000. In one form, a cross-section of which is shown in Fig. 9a, the humidification chamber 5200 may comprise a humidifier wick 5230, a water feed inlet 5206 and a heating element 5220.

Preferably, the humidification chamber 5200 is in fluid communication with, and receives water from, the water oir 5110 through the water feed inlet 5206. The water feed inlet 5206 may se an inner diameter of between about 0.5 mm to 3 mm in some forms, such as 1 mm, 1.5 mm, 2 mm or 2.5 mm. Preferably, the water feed inlet 5206 is sufficiently large to reduce a risk of obstruction of the water feed inlet 5206, for example due to a up of contaminants.

In one form, the humidification chamber 5200 may comprise an outer housing 5202 configured to provide thermal insulation to the outside, as well as to protect an interior of the humidification chamber 5200 such as any components therein. The outer g 5202 may comprise a plurality of portions such as an inlet portion 5202a, heater cover n 5202b and outlet portion 5202c that are coupled together. The inlet portion 5202a may comprise the air inlet 5002 and the outlet portion 5202c may comprise the air outlet 5004 as shown in Fig. 9a. The water feed inlet 5206 is shown located in the inlet portion 5202a, but may be located in any one of the portions 5202a, 5202b, 5202c. If le water feed inlets 5206 are present, the additional water feed inlets 5206 be located in one or more of the portions 5202a, 5202b, 5202c of the outer housing 5202. The heater cover portion 5202b may be configured to locate and retain the g element 5220. In some arrangements the heating element 5220 may be retained between an inner housing 5204 and the heater cover portion 5202b of the outer g 5202 as shown in Fig. 9a. The inner housing 5204 is configured to isolate the heating element 5220 from exposure to moisture, yet allow heat transfer to occur from the g element 5220 to the humidifier wick 5230.

Fig. 9b shows a humidifier 5000 in another form according to the present technology. In this form, the heater cover portion 5202b of the outer housing 5202 is 505809DIV4 set away from the g element 5220 so as to provide an air gap, for example for thermal insulation. The heater cover portion 5202b may also encloses the water feed inlet 5206 for protection as shown in Fig. 9b.

Suitable materials for the inner housing 5204 may include thermally tive materials, such as aluminium or its alloys, or thermally conductive polymeric/thermoplastic materials such as Polycarbonate/Acrylonitrile Butadiene Styrene (PC/ABS). Suitable materials for the outer housing 5202 may include polymeric materials such as PC/ABS, and the outer housing 5202 may include meric portions such as thermoplastic elastomer (TPE). The outer housing 5202 may se a diameter of between about 10mm and 50mm, and be about 1-3 mm thick. The thickness of the inner housing 5204 may be about 1-3 mm, and may vary according to the material used, for example in order to e sufficient heat tivity. It is to be understood that such dimensions and ements are exemplary and are not intended to be ng. It is to be understood that the inner housing 5204 and/or the outer housing 5202 may have a different shape to those shown and/or be formed of a ent number of ns, such as one, two, four, five or more portions.

According to one aspect, the water feed inlet 5206 may be in fluid communication with the water delivery mechanism 5150 to deliver water to the humidifier wick 5230 as shown in Fig. 8. In some cases, the humidifier 5000 may comprise a water filter 5214 configured to reduce ingress of foreign matter into the humidification chamber 5200 and/or the wick 5230 through the flow of water. The water filter 5214 may be located at or near an outlet of the humidifier reservoir 5110 (as shown in Fig. 8). The water filter 5214, or parts thereof, may be configured to be replaceable or cleanable. In some forms, the water filter 5214 may comprise a deioniser (not shown) where quality of the water in the reservoir 5110 is low.

In some arrangements (not shown), the water feed inlet 5206 may be located closer to the air outlet 5004 than the air inlet 5002. Such an arrangement may encourage at least some portion of the flow of water in the wick 5230 to travel in an opposing direction to the direction of the air flow in the humidification chamber 5200.

Thus, the temperature and humidification gradient within the water in the wick 5230, as well as within the air flow may be optimised to optimise the differential temperature and humidification therebetween in order to improve humidification performance.

According to another aspect, the humidification chamber 5200 may further comprise an air flow baffle 5208 (as shown in Fig. 9a and Fig. 10) configured to promote local turbulence and/or increase the ative surface area, such as by extending a length and/or a residence time during which the flow of air is in the humidification chamber 5200, for e to improve humidification performance. In one form, the air flow baffle 5208 may force the flow of air to travel in a tortuous path, such as a helical path as shown in Fig. 10. ion of the air flow baffle 5208 in a fication chamber 5200 may help reduce a size, such as a length, of the humidification chamber 5200, in ison to a length of the path for the air flow in the humidification chamber 5200 used without such an air flow baffle 5208.

Alternatively, or additionally, the humidification chamber 5200 may further comprise one or more jump or trip elements (not shown) along an evaporation surface configured to improve humidification performance.

In some forms of the present logy the air flow baffle 5208 may comprise a membrane. The air flow baffle 5208 may also further comprise acoustic elements for noise reduction, such as a tuned chamber (or resonator) configurations, or a number of narrow flow paths configured to encourage development of laminar flow and reduce noise. In one form, the flow paths formed by the air flow baffle 5208 may be configured to provide a high inertance to assist in reducing radiated noise. In some ements, the air flow baffle 5208 may comprise variable damping properties for reducing noise and/or vibrations.

In some arrangements, the humidification chamber 5200 may comprise a bypass port for sensing one or more properties of the flow of air as it passes through the humidification chamber 5200.

Additionally, or alternatively, the fication chamber 5200 may be configured to only add humidity to the flow of air for an inhalation phase of a patient’s breath. In one form, the humidifier 5000 may comprise a bypass path which may be used divert the air flow away from the humidification chamber 5200 for at least a part of a breath cycle, for example using a valve. This may allow for delivery 505809DIV4 of an air flow to the patient interface 3000 t fication during some parts of a breath cycle, such as during exhalation. .5.2.3.1 Heating element 5220 The amount of moisture, or absolute humidity, that a flow of air is able to retain in vapour form varies according to a temperature of the flow of air.

In some cases, the flow of air ed by the humidifier 5000 may be too cold to retain adequate absolute ty for delivery to the entrance to the airways of the patient 1000. Furthermore, delivery of cold air may cause discomfort to the t 1000 as described above. Thus, a humidifier 5000 may comprise a heating element 5220 configured to output heat, for example to heat the flow of air. In one form, the heating element 5220 may be located in the humidification chamber 5200, such as between the inner housing 5204 and the outer housing 5202 as shown in Fig. 9a.

Alternatively, or additionally, the humidifier reservoir 5110 may comprise a reservoir heating element 5221 to heat water prior to it entering the humidification chamber 5200 as shown in Fig. 8.

The heating element 5220 may heat the flow of air as it passes through the fier 5000, as well as to assist humidification in the fication chamber 5200 such as by heating the humidifier wick 5230. Accordingly, the heating element 5220 may be configured so that it provides sufficient thermal energy for heating and vaporisation at the highest requirements respectively, that is, where the t air is cold and dry.

The heating element 5220 may be configured in one of a number of ways whilst meeting the above requirements. In one form, a heating element 5220 may comprise an approximately 10 cm2 surface area that generates a maximum thermal output of 40 Watts. In r form, a heating element 5220 may se an approximately 40 cm2 surface area with the same maximum thermal output value of 40 Watts. It should be understood that the maximum thermal output value need not be limited to 40 Watts. Examples of relationships between a power output of a humidifier 5000 are shown in Fig. 17 and Fig. 19, and an example of a relationship between added humidity and temperature of the heating element is shown in Fig. 18. 505809DIV4 According to one aspect of the present technology, the heating element 5220 may be zoned. That is, the heating element 5220 may comprise multiple sections, or zones, that may be controlled discretely and/or have variable properties.

In some cases, variable properties of the zones may include shape, heat output, insulation, proximity to the wick 5230 or proximity to water feed inlet 5206. Yet further, each zone may be controlled independently of each other by the humidifier controller 5550, and in some cases controlled relatively to each other. An example of a heating element 5220 which may allow ve control of the zones is shown in Fig. 11. In this example, the heating element 5220 may se four zones 5220_1, 5220_2, 5220_3 and 5220_4, n the heating output of each zones may be configured to be 10%, 20%, 30% and 40% of a total heat output of the heating element 5220. There may be a different number of heating zones, such as two, three, five or more zones and ties of the zones such as their shape, size or maximum heat output may vary.

One suitable form of a g element 5220 may comprise a resistive electrical track on a circuit board. The circuit board may comprise a ate which could be used as a thermally conductive, electrically resistive barrier between the resistive electrical track and the wick 5230. In one form, the heating element 5220 may se a le circuit board. In another form, the heating element 5220 may comprise a metallic thermally conductive substrate, which is separated by a dielectric laminate layer from the heating track. Alternative forms of a g element 5220 may be also suitable such as an inductive heater, if the g element 5220 is configured to be able to provide a heat output to the wick 5230 and/or the humidification chamber 5200.

In another form, the resistive electrical track of the heating element 5220 may comprise a resistive wire. The resistive wire may wrap around an outer housing 5202 as shown in Fig. 20, for example by forming a plurality of loops around the surface. In one example, each stand of wire may be bonded to adjacent stand(s) of wire, such as by an adhesive (e.g. epoxy). In another example, each strand of wire may comprise an insulating layer, which may be further configured to bond to adjacent strand(s) of wire when heat is applied o. Thus the plurality of loops of the resistive wire may be formed around the outer housing 5202, and heat may be 505809DIV4 applied to the heating element 5220 (e.g. externally, or by applying a current through the heating element 5220) to bond the strands together.

As described above, the heating element 5220 may take one of a number of possible forms in shape and/or construction. Thus, it should be understood that although the heating element 5220 is shown (e.g. in Fig. 9a and Fig. 11) to be a cylindrical shape, it need not be limited to such a shape. For e, the heating element 5220 may be constructed as a flat, rectangular sheet, as an extruded arc shape, as a rectangular prism, or a plurality of parallel sheets, among others.

The heating element 5220 may be disposable in some cases. For instance, the entire humidification chamber 5200 may be disposable wherein the heating element 5220 is formed integrally within the humidification chamber 5200 as a part of a disposable component. Alternatively, the heating element 5220 may be ured to be able and easily ed by removal from the humidification chamber 5200, for example by inserting, such as g, into the humidification chamber 5200 for installation. .5.2.3.2 Humidifier wick 5230 In one aspect of the present technology, the fier 5000 may comprise a humidifier wick 5230. The humidifier wick 5230 may be configured to retain a volume of water, which may be received from the reservoir 5110 for evaporation to humidify the flow of air before it is delivered to the patient 1000.

A m volume of water able to be retained by the fier wick 5230, or a water capacity of the humidifier wick 5230, may be predetermined. In one aspect, the water capacity of the humidifier wick 5230 is preferably small enough to ensure a short se time of the humidifier 5000. According to another aspect, the water ty of the humidifier wick 5230 is sufficiently large to allow adequate humidification at the t flow rates and driest ambient conditions, by ensuring an adequately large surface area of water. The water capacity of the humidifier wick 5230 may be approximately 10 g, however other values may also be appropriate such as approximately 2 g, 6 g, 15 g, 20 g, 30 g, or any other values therebetween. In other forms, a larger or a smaller water capacity of the humidifier wick 5230 may be suitable. 505809DIV4 A condition wherein the water capacity of the humidifier wick 5230 is met by the water t in the humidifier wick 5230 may be referred to as ‘saturation’ or ‘flooding’ of the wick 5230. In some cases, it may be preferable to operate the humidifier 5000 such that the humidifier wick 5230 is not saturated during use.

Disadvantages caused by saturation of the humidifier wick 5230 may include introduction of water droplets in the humidifier 5000 and/or the air circuit 4170 due to spitting. Detection of saturation of the humidifier wick 5230 may be thus desirable, which will be described in further detail below. In some cases, the air circuit 4170 may comprise a portion of the wick 5230, or a secondary wick (or water trap), to rate any potential problems related to spitting, such as by absorbing any spitting or rainout.

According to one aspect, the wick 5230 may be constructed with nonhomogenous ry and/or construction. Thus, one or more properties of the wick 5230 such as the water ty, surface area exposed to air, or heat conductivity may be varied for each area of the wick 5230. For instance, the wick 5230 may be nonhomogenous along the direction of air flow, or along a distance from the water feed inlet 5206, for e so that the wick 5230 becomes r the further away from the water feed inlet 5206. In one form, geometry of the wick 5230 may vary in one or more of the depth, number of layers, the density and/or material of the wick 5230.

For example, the humidifier wick 5230 may comprise one or more layers, such as a first layer 5230a and a second layer 5230b as shown in Fig. 12. The one or more layers may vary in form and/or ons. In one instance, the first layer 5230a may be a transport layer in communication with the water feed inlet 5206, and the second layer 5230b may be an evaporation layer laid over the first layer 5230a and in contact with the flow of air. In this construction, the first layer 5230a may be configured to se storage of water per volume and/or fast transport of water, and the second layer 5230b may be configured for improved evaporation characteristics, for example by increasing an exposed surface area per volume. In some forms, the humidifier wick 5230 may be configured so that one or more layers may be replaced independently of each other, n the one or more layers may or may not be identical in form and/or function. 505809DIV4 In some forms, the humidifier wick 5230 may comprise a surface configured to se a total surface area exposed to the flow of air. This may se the area over which the water retained by the humidifier wick 5230 is in contact with the air flow, in order to improve humidification ency. For instance, the humidifier wick 5230 may comprise a corrugated inner surface as shown in Fig.

A humidifier wick 5230 according to the present technology may comprise a single continuous component, multiple ents working as an assembly, or a discontinuous, discrete collection of wicking materials and/or elements. In the present document all or any of the above variations will be referred to as a ‘humidifier wick’ 5230. A person skilled in the art would understand that the humidifier wick 5230 need not be constructed as a single piece of wicking material.

According to another aspect, the humidifier wick 5230 may be heated, for example by the heating element 5220. One advantage of a heated wick 5230 may be that a rate of evaporation may be controlled. In one form, the humidifier wick 5230 may be thermally coupled to the heating element 5220, for example by contact as shown in Fig. 12.

A mance of the humidifier wick 5230 may degrade over time and/or usage, and in some cases the humidifier wick 5230 may no longer be suitable for use.

For instance, n matter, such as particulates from the water, may collect or build up on the humidifier wick 5230 as it is evaporated. In some cases, collection of foreign matter may reduce water capacity and/or heat conductivity of the humidifier wick 5230. In some cases, the humidifier wick 5230 may deteriorate over time, possibly even without any use of the fier 5000. Still r, the foreign matter collected on the humidifier wick 5230 may be removed from the humidifier wick 5230 and be entrained onto the flow of air, which may be undesirable.

Thus, in one aspect of the present technology, the humidifier wick 5230 may be cleaned and/or replaced. Furthermore a condition of the humidifier wick 5230 may be determined, such as its water capacity and/or its remaining usable life, and provide an indication or e when the fier wick 5230 needs replacing or to an expected time to replacement. 505809DIV4 According to another aspect, a pattern of distribution of foreign matter on the humidifier wick 5230 may be determined and/or controlled. For instance, the humidification chamber 5200 may be ured to encourage collection of foreign matter on the humidifier wick 5230 according to a predetermined n. Still further, the predetermined pattern of foreign matter build-up on the humidifier wick 5230 may be used as an indicator of a remaining life of the humidifier wick 5230. For example, the humidifier wick 5230 may be ured so that foreign matter may begin to collect from one predetermined region of the humidifier wick 5230, and for the collection to grow in a predetermined direction. Then, detection of a build-up of foreign matter, for example in a predetermined life-indicator region may be used to indicate that the humidifier wick 5230 may be no longer suitable for use.

A cross-section of the humidifier 5000 (wick frame 5232 not shown) showing an ement of a humidifier wick 5230 in use is shown in Fig. 14. In this example, the humidifier wick 5230 holds a volume of water, however the volume of water may be less than the water capacity of the fier wick 5230. Accordingly the humidifier wick 5230 may be shown to comprise of two regions, a wet region 5230_W and a dry region 5230_D, separated by a water boundary, is shown as B. Typically, formation or collection of any foreign matter from water onto the humidifier wick 5230 may predominantly occur at the boundary edge, as this is the point at which particulates are dried. Accordingly, one of the aspects of the present technology relates to a control of the water boundary 5230_WB, through construction of the wick 5230 and/or foreign matter management algorithms, as described r below.

In one form, the wick 5230 may be configured to allow washing, e.g. in a dishwasher, disinfection using another agent, and/or using a microwave. Additionally, or alternatively, the humidifier wick 5230 may comprise an antimicrobial or cterial agent such as silver. Yet further, the humidifier 5000 may comprise eaning algorithms (such as a rden reduction algorithm) as will be described further below.

According to one aspect, the humidifier wick 5230 may further comprise added matter such as a drug to be uced to the flow of air, or a life indicator. The life indicator may comprise a coloured portion which changes colour to indicate to the 505809DIV4 user or the patient 1000 that the humidifier wick 5230 should be replaced. The humidifier wick 5230 may comprise a drug which may be ed by vaporisation to the flow of air to be delivered to the patient 1000.

The fier wick 5230 may se, or be combined with, the heating t 5220 in some cases. For instance, the wick 5230 may comprise a printed carbon portion which may form resistive tracks for heating, and a paper-based portion for water retention and evaporation which also acts as the substrate for the printed carbon portion. In one form, the heating element 5220 may be coupled (e.g. printed) onto one or both sides of the wick 5230 so as to create an integrated component. The integrated ent may further comprise one or more connectors which may be coupled (e.g. d) onto one or both sides of the wick 5230, for example for connection to the controller 5550.

The humidifier wick 5230 may comprise one or more humidifier transducers. The humidifier transducers and humidifier thms which may receive inputs from the humidifier transducers are bed in further detail below.

In another aspect, the humidifier wick 5230 may be configured in a shape to facilitate easy insertion and/or removal with respect to the humidification chamber 5200. In one form, a portion of the humidifier wick 5230 such as a tab (not shown) may be configured to be accessible for removal while the humidifier wick 5230 is in its operating position. Yet r, the humidifier 5000 may be configured as shown in Fig. 14 such that a component (such as an outer housing component 5202_c) may be removed to allow access to the humidifier wick 5230. Additionally, or alternatively, the humidifier wick 5230 may be ured in a frustro-conical shape complementarily to a similarly shaped humidification chamber 5200, so that it would self-locate during insertion into its operating position. .5.2.3.3 Wick frame 5232 According to one aspect, the humidifier 5000 may comprise a wick frame 5232 shown in Fig. 9a and Fig. 10. The wick frame 5232 may be coupled to the wick 5230, for instance to locate and/or shape the wick 5230, maintain the wick 5230 in close ity to the heating element 5220, and/or to prevent an increase in flow impedance which may occur due to a deformation of the wick 5230. The wick frame 505809DIV4 5232 may promote, or maintain, thermal contact between the wick 5230 and the heating element 5220 by assisting in locating and/or shaping the wick 5230 as ed. In a form shown in Fig. 10, the wick frame 5232 may comprise a wick locator 5233 such as a shoulder as shown, to assist in on of the wick 5230 in relation to the wick frame 5232 in assembly.

The wick frame 5232 may be further configured to assist in removal and/or ion of the wick 5230 with respect to the humidifier 5000, for instance by providing a grip surface 5232_G to assist a user and/or the patient 1000 to locate and/or hold the wick frame 5232. The grip surface 5232_G may be marked (e.g. using colours and/or indicators) for identification, and/or textured to assist the users to hold onto the grip . In some forms, where the humidifier wick 5230 is disposable, the wick frame 5232 may be configured to be disposed with the humidifier wick 5230, for example by being integrally formed. In other cases, the wick frame 5232 may be configured to accept and hold the humidifier wick 5230, for example so that the wick 5230 may be replaced while the wick frame 5232 is removed from the humidifier 5000. Then the wick frame 5232 may accept a new wick 5230 and be inserted into the humidifier 5000. In some forms, the wick frame 5232, the wick 5230 and the heating element 5220 may be coupled together and configured to be disposable as a unit.

According to another aspect, the wick frame 5232 may be configured to be printed by a 3-D printer, for example by the patient 1000, or a ver, such as in a hospital or in a home environment. Alternatively, or additionally, the wick frame 5232 may be moulded as one component, or an assembly of a plurality of d components. In some forms, the wick 5230 and the wick frame 5232 may be a single component.

In one form, the wick frame 5232 may further comprise an air filter am and/or downstream of the wick 5230. The air filter may be placed upstream of the wick 5230 in order to reduce introduction and/or collection of foreign matter onto the wick 5230. Alternatively, or additionally, the air filter may be placed downstream of the wick 5230 in order to reduce incidence of any foreign matter ling from the wick 5230 to the patient 1000. 505809DIV4 According to another aspect, the wick frame 5232 may comprise the air flow baffle 5208 bed above. Where the wick frame 5232 is combined with the air flow baffle 5208, the wick 5230 may form one surface of the path of the flow of air. This configuration may be advantageous in that the length of t is increased n the flow of air and the wick 5230, which may improve humidification. .5.2.3.4 Humidifier filter 5240 One or more humidifier filters 5240 may be used in some arrangements of the humidifier 5000. The humidifier filter 5240 may be used to reduce the amount of undesirable components from the flow of air, for example by preventing the particulates that may have originated from evaporated water from being introduced into the flow of air. A humidifier filter 5240 may be placed anywhere in the humidifier 5000, such as at or near the inlet 5002 (as shown in Fig. 14), the outlet 5004 (as shown in Fig. 16), or therebetween (not shown). A filter (not shown) located ream of the humidifier 5000, for example in the air circuit 4170, may substantially perform a similar function as a humidifier filter 5240 by ng the amount of undesirable component from the flow of air. .5.2.4 Humidifier transducers ing to one aspect of the present technology, the humidifier 5000 may comprise one or more fier transducers configured to generate a signal indicative of the sensed characteristic, such as air flow rate, pressure, temperature or humidity. Thus the humidifier 5000 may comprise one or more flow sensors 5512 (as shown in Fig. 15), one or more temperature sensors (e.g. , 5514_2, 5514_3, 5514_4 as shown in Fig. 15), and/or one or more humidity sensors 5516 (as shown in Fig. 16) as well as any number of other types of sensors.

Some humidifier transducers may be located in the humidifier 5000 (e.g. g element temperature transducer 5514_HE shown in Fig. 16), however humidifier transducers may also be located outside of the humidifier 5000 in some cases, for example in the air circuit 4170, or in the patient interface 3000.

Suitable locations for each of the one or more humidifier transducers may vary according to their purpose and/or algorithms which may use as inputs signals generated by each of the one or more humidity sensors 5516. In some cases, 505809DIV4 transducers configured to generate a signal indicative of a sensed characteristic in one of the pneumatic path, such as the RPT device 4000, may be used to determine the sensed characteristics in another part of the pneumatic path, such as the humidifier 5000. .5.2.5 Humidifier controller 5550 In one form, the humidifier 5000 may comprise a humidifier controller 5550, which may be a standalone ller or a part of the central controller 4230 (as shown in Fig. 4c). The humidifier ller 5550 may monitor and/or control one or more operating parameters of the humidifier 5000 based on inputs from components such as other components of the humidifier 5000 and/or the RPT device 4000.

For ce, humidifier 5000 may e inputs from such components as humidifier transducers, input devices 4220 or memory 4260. Furthermore, the humidifier 5000 may output signals to the heating element 5220 or the water ry ism 5150. .5.3 Humidifier algorithms 5600 Various humidifier algorithms 5600 (e.g. shown in Fig. 21) are described below. Although they are ed to ‘humidifier algorithms’, it is to be understood that these algorithms need not be stored in and/or executed by the humidifier 5000.

The term ifier algorithms’ is used herein to indicate that the algorithms relate to the humidifier 5000. For example, the humidifier algorithms 5600 may be executed by the central controller 4230 and stored in memory 4260 of the RPT device 4000. In some instances, the thms 5600 may be stored and/or executed from an external computer such as a smartphone in communication with the humidifier 5000. .5.3.1 Humidifier condition determination / fault mitigation algorithms According to one aspect, the humidifier 5000 may comprise algorithms configured to determine, or detect, one or more conditions of the humidifier 5000 and/or its components. In some cases, the humidifier 5000 may further comprise fault mitigation algorithms configured to ameliorate, or mitigate one or more detected fault conditions. 505809DIV4 The humidifier condition determination algorithms may detect or determine conditions of humidifier components such as the water reservoir 5110, water ry mechanism 5150, humidifier wick 5230, heating element 5220 or humidifier transducers. The conditions detected or determined may include: water volume, such as in the water reservoir 5110, water flow rate, such as from the water delivery mechanism 5150, or water capacity and/or water content of the humidifier wick 5230. .5.3.1.1 Wick condition determination thms 5610 As described above, a performance and/or suitability for use of the humidifier wick 5230 may change over time and/or usage, for example due to buildup of foreign matter on the wick 5230 or degradation of the humidifier wick 5230.

Accordingly, the water ty of the fier wick 5230 may change, which may affect the amount of humidification which can be provided to the flow of air.

According to another aspect of the present technology, the humidifier 5000 may comprise one or more wick condition determination algorithms 5610 for determining one or more conditions of the humidifier wick 5230. The one or more conditions of the humidifier wick 5230 to be determined may e suitability of the wick for use, water capacity, water content, or remaining usable life of the humidifier wick 5230.

In some forms (e.g. a wick condition ination algorithm 5610A as shown in Fig. 22), a wick condition determination algorithm may e one or more inputs from step 5610A2 to determine one or more conditions of the humidifier wick 5230 in step 5610A4. The one or more conditions of the humidifier wick may be determined by comparing the inputs to thresholds such as in step 5610A3. The one or more inputs may e wick characteristic, wick type, wick model, date of cture, water capacity, water content, date of last replacement, time of usage, ty of water evaporated using the wick 5230, number of times that the wick 5230 has been washed, or any others which may indicate a condition and/or a property of the wick 5230. Yet further, the wick condition determination thms may receive inputs in some cases relating to ambient conditions. A wick condition determination algorithm may then determine one or more conditions of the wick 5230 based on one or more of the above inputs. Some of the wick conditions determined may be used as 505809DIV4 r inputs to other wick conditions. For example, conditions such as water capacity and/or the water content of the wick may be used as inputs to determine other wick ions such as a remaining usable life of the wick 5230 or to determine whether the wick may be suitable for use, as shown in step 5610A5 of Fig. 22. If the wick 5230 is determined to be no longer suitable for use, the wick condition determination algorithm 5610 may generate a corresponding signal (e.g. in step 5610A6), for example to the humidifier controller 5550 so that the humidifier 5000 may communicate to the user of a need to change the wick 5230.

In some cases, a calibration algorithm may be able to indicate when a wick 5230 has been replaced or washed, for example based on to an increase in its water capacity.

A wick ion determination algorithm 5610 may determine a water capacity of the wick 5230 in absolute terms or relative terms, for example as shown in an example algorithm 5610B shown in Fig. 23. That is, the water capacity of the wick 5230 may be determined as an absolute quantity of water that the wick 5230 is able to hold (as shown in step 5160B3 of Fig. 23) or as a relative ty (as shown in al step 5160B5 of Fig. 23) such as in relation to a predetermined water capacity of the wick 5230 (as shown in input step 5160B4 of Fig. 23), or in relation to a minimum water capacity of the wick 5230 (not shown). The water capacity of the wick 5230 may be assessed prior to use (such as in step 5610B5) to determine that the wick 5230 is le for use. In some forms, the wick condition determination algorithm 5610 may further determine whether the wick 5230 is suitable for use (step 5610B6) and/or indicate the unsuitability of the wick (step 5610B7) based on the determined water capacity of the wick 5230.

In one form, a wick condition ination algorithm 5610 may determine a water content of the humidifier wick 5230 as a proportion of its water capacity. The wick condition ination algorithm 5610 may in some forms indicate when a wick saturation condition is reached, which is to say that the full water capacity of the wick 5230 has been met and/or exceeded. In some cases, determination of wick saturation may be used as an input to another fier algorithm, for example to stop, or slow down, operation of the water ry mechanism 5150. 505809DIV4 In another aspect, the wick condition determination algorithm may determine a remaining life of the wick 5230 based on the current water capacity of the wick 5230 and the rate of change of the water capacity of the wick 5230 ing to one or more previously measured water capacity values of the wick 5230.

In one form (e.g. shown in Fig. 24), a wick condition ination algorithm 5610 may determine a condition of the humidifier wick 5230 based on one or more temperatures at or near the humidifier wick 5230 (in step 5610C2), for example determined by sensing or measuring. In some cases, the one or more temperatures may be compared with reference values (in step 5610C3), which may be expected atures, atures measured from nearby s, or previously measured temperatures, to determine the condition of the humidifier wick 5230 (in step 5610C4). The expected temperatures may be based on one or more of operating parameters of the humidifier 5000, such as a heat output from the heating element 5220, a flow rate of air through the humidifier 5000, and a water flow rate through the water feed inlet 5206, as well as any number of others. In some forms, the expected atures may be determined from one or more look-up tables or equations based on the one or more operating parameters.

According to another aspect, the one or more temperatures may be measured and/or analysed relative to each other, for instance based on any temporal or spatial patterns. In one form, measures of temperature in a humidifier 5000 at various temperature sensors such as 5514_1, 5514_2, 5514_3, 5514_4 (see Fig. 15) may be measured and compared to each other. In another form, measured of temperature in a humidifier 5000 at a temperature sensor such as 5514_1 may be ed against another measure at the same temperature sensor 5514_1 which was taken at r time. For instance, an analysis may compare rates of change of the one or more temperatures against reference values. Alternatively, or additionally, a spatial distribution of temperatures, for e of the one or more temperatures ve to each other, may be compared against nce values.

In one form, one or more of the operating conditions of the humidifier 5000 may be varied while monitoring a response of one or more temperatures to determine a condition of the humidifier 5000. Examples of operating conditions to be varied may include a heat output from the heating element 5220, an air flow rate 505809DIV4 through the humidifier 5000, and a water flow rate through the water feed inlet 5206 as described above. However, the operating ions may include any number of other parameters.

One ement of the humidifier 5000 sing temperature sensors 5514_1, 5514_2, 5514_3 and 5514_4 is shown in Fig. 15. In this arrangement, measured temperatures and reference values may be ed at one or more of the temperature sensors 5514_1, 5514_2, 5514_3 and 5514_4 to determine a ion of the humidifier wick 5230.

In one example, measured temperatures at temperature sensors 5514_1, 5514_2, 5514_3 and 5514_4 may be 40°C, 41°C, 40°C and 52°C respectively, while the expected temperatures may be 40°C, 40.5°C, 41°C and 41.5°C, at a water flow rate of 1g/min. In this case, a wick condition determination algorithm 5610 may determine that the water flow rate is sufficiently high so that the wick 5230 should be wet around the temperature sensor 5514_4, and thus determine the humidifier wick 5230 to have a d water capacity around the temperature sensor 5514_4.

In r arrangement of the humidifier shown in Fig. 16, a temperature sensor 5514_5 may be placed at a periphery of the humidifier wick 5230 st from the water feed inlet 5206 to indicate wick saturation. A wick condition determination algorithm (e.g. example algorithm 5610C) may be configured to monitor the temperature at the sensor 5514_5, to determine a flooded condition (in step 5610C5).

Thus for example, if a temperature measured at the sensor 5514_5 is at or below a predetermined old, such as 2°C-5°C or more below a temperature of the heating element 5220, the wick 5230 may be deemed to be flooded, or saturated, by the wick condition determination algorithm 5610. In one form, the wick condition determination algorithm 5610 may determine a water capacity of the wick 5230 by measuring a time for the wick 5230 to be saturated. Other sensors which may be suitable for use to indicate wick saturation may include an ultrasonic sensor, a noise sensor, a rain sensor and/or an image processing sensor. In some instances, where the wick is determined to be flooded, the water delivery ism 5150 may be stopped (in step ), and otherwise the water delivery mechanism 5150 may be continued to operate (in step 5610C7).

In another form, the wick condition determination algorithm may determine a remaining life of the wick 5230 based on one or more mechanical properties of a wick 5230. The one or more mechanical properties may include noise/vibration characteristics such as a muffling or an acoustic profile. In other forms, a magnetic and/or optical characteristic of the wick 5230 may be used to determine a remaining life of the wick 5230.

In some forms, a wick condition determination algorithm 5610 may produce one or more outputs to be used by another fier algorithm. For instance, the wick condition determination algorithm 5610 may output water capacities of various zones of the wick 5230. Where a humidifier wick 5230 is determined to have a reduced water capacity in one zone, and the heating element 5220 comprises a ity of heating zones, a heat output by the g element 5220 to the corresponding heating zones may be varied ing to the condition of the humidifier wick. 1.2 Plausibility check algorithms 5620 According to another , the humidifier may comprise one or more plausibility check algorithms 5620 configured to test for errors in operation of the humidifier 5000. The plausibility check algorithms 5620 may also check for performance of one or more individual components of the humidifier 5000.

An example bility check algorithm 5620A (shown in Fig. 25) may receive as inputs inlet and/or ambient conditions (step 5620A2), such as measures of a temperature at the air inlet 5002, ty at the air inlet 5002, ambient temperature, and ambient humidity. The plausibility check thm 5620A may further e as inputs operating parameters (step ) of the humidifier 5000 such as a heat output of the heating element 5220 to the wick 5230 and a flow rate of water to the wick 5230. The plausibility check algorithm 5620A may determine predicted outlet conditions (e.g. humidity/temperature at outlet, as shown in step 5620A4) based on the inputs. In one form, the plausibility check algorithm 5260 may monitor outlet conditions (step 5620A5), such as a measured temperature at the air outlet 5004 and a measured humidity at the air outlet 5004. The plausibility check algorithm may compare the measured temperature and/or humidity against to test plausibility of the measured temperature and/or the humidity. If the temperature at the air outlet 5004 505809DIV4 and/or the humidity at the air outlet 5004 is found to be implausible (step 5620A6), for example as they deviate more than a threshold amount from a predicted value thereof respectively, the plausibility check algorithm may indicate a fault condition. It is noted that in other forms of the plausibility check algorithm 5620, inputs, predicted values and measured values may be varied. For example (not , the inlet/ambient conditions and outlet conditions may be monitored to determine ted operating ters, and to compare the predicted operating parameters with measured operating parameters in order to determine plausibility of the measurements. .

For instance, at an absolute ambient humidity of 10 mg/L, at an air flow rate of 35L/min, a predicted absolute humidity of the flow of air at the air outlet 5004 may be . Accordingly, if the water delivery ism 5150 has been delivering a water flow rate of 700mg/min, evaporation of the delivered water would add (700mg/min) / (35L/min) = 20mg/L of absolute ty to the flow of air at the air outlet 5004. However, after a old period of time, for example 5 minutes, the absolute humidity at the air outlet 5004 is below a threshold amount of the target absolute humidity, the plausibility check algorithm may determine that the humidifier 5000 is not operating correctly and indicate a fault condition.

In another form, a plausibility check algorithm 5620 may perform a test cycle to check operation of the humidifier 5000. For instance, the plausibility check algorithm 5620 may change the heat output of the heating element 5220 and/or the water flow rate of the water delivery mechanism 5150 and check a response of the humidifier 5000 using one or more of the humidifier transducers.

In another form, a plausibility check algorithm 5620 may check for correct performance of a component such as a water delivery mechanism 5150, by comparing a water flow rate in comparison to a rate of movement of the water pump 5152.

The plausibility check thms 5620 may be ured to run at one or more of predetermined intervals, predetermined rs or user/patient requests. For example, the plausibility check algorithm 5620 may be performed at start-up of the humidifier 5000, at monthly intervals, at requests of the patient 1000, at requests from 505809DIV4 a remote location such as a health care provider’s er, or when the humidity sensor 5516 detects that the output humidity from the humidifier 5000 is below the target ty for over a threshold period of time. In other cases, the plausibility check algorithms 5620 may be ured to be running continuously (or periodically) while the humidifier 5000 is in operation. .5.3.1.3 Pump condition determination algorithms 5630 In one form, the humidifier 5000 may comprise one or more pump ion determination algorithms 5630. The pump condition determination algorithm may determine, for example, any blockages in the pump 5152 or any fault conditions of the pump 5152 such as an over-temperature condition, an over-current ion or leak. In one form, pump condition determination algorithm(s) may be performed at humidifier start-up (e.g. prior to commencement of therapy and/or humidification) to determine the suitability of the pump 5152 for operation. .5.3.1.4 Fault mitigation algorithms One aspect of the present technology relates to use of fault mitigation thms.

In one form, a fault mitigation algorithm may be configured to respond to outputs of wick condition determination thm 5610 and/or the plausibility check algorithms 5620. For instance, the wick condition determination algorithm 5610 may determine a condition of the humidifier wick 5230 and output a signal indicating that the fier wick 5230 may no longer be suitable for use. Then, the fault mitigation algorithm may act to reduce a flow rate of air through the humidifier 5000, reduce a water flow rate from the water delivery mechanism 5150, and/or possibly stop operation of the humidifier 5000 and/or the RPT device 4000. .5.3.2 Humidifier control algorithms .5.3.2.1 fication algorithms 5650 According to one aspect, fication algorithms 5650 may be configured to control components of the humidifier 5000 to manage the humidity of the flow of air delivered from the humidifier 5000. 505809DIV4 In one form, the humidification algorithm 5650 may receive as inputs one or more target output conditions such as target output humidity or target output temperature, one or more ambient conditions such as ambient humidity or ambient temperature, and/or one or more measured output conditions such as measured output humidity or measured output temperature. Other possible inputs for the humidification algorithm 5650 may include characteristics of an air circuit 4170 such as its , or characteristics of the patient interface 3000 such as its type, or vent characteristics. In some cases, characteristics of the air circuit 4170 and/or the patient interface 3000 may be input by a user, r in other cases, they may be detected by an identification module or a recognition system, such as that bed in a PCT application WO/2010/091462, the entire contents of which is included herewithin by cross-reference. The humidification algorithms 5650 may r use as inputs one or more of a presence of a patient 1000, a flow rate of the flow of air through the air circuit 4170, a pressure gradient of the flow of air, or a breath rate of a patient 1000.

The humidification algorithms 5650 may in one form operate so that the flow of air delivered by the humidifier 5000 is at or close to 100% ve humidity, although others may be possible, such as (but not limited to) 40%, 50% 60%, 70%, 80% or 90%. One advantage of the present technology may e a shortened response time as described above. The humidification algorithm may thus be configured in some forms to only cease operation where a 100% output ve humidity is detected, without producing significant, or any, rain-out.

According to another , a humidification algorithm may be programmed to behave in a non-linear fashion as a response to a change in ing conditions. For instance, the humidification thm may be programmed so that when a mask leak ses e.g. from 5L/min to 10L/min, increasing the total flow rate from 35L/min to 40L/min, the heat output from the heating element 5220 and the water flow rate from the water delivery mechanism 5150 is increased by a greater amount than 5/35. The response by a humidification algorithm based on a change in operating conditions may be delayed in some cases.

In another , the humidification algorithm 5650 may be configured to determine suitable target conditions according to the t conditions, for example without the need for a user (or a patient 1000) to change the desired output condition. 505809DIV4 For instance, the humidification algorithm 5650 may direct the humidifier 5000 to output warmer air at a higher humidity where the ambient conditions are colder and drier in comparison to where the ambient conditions are warmer and more humid.

In some forms of the humidification algorithm 5650, the heat output to the humidifier wick 5230 and the water flow rate to the fier wick 5230 may be controlled as a function of each other. For instance, where the heat output to the humidifier wick 5230 is limited, such as due to low power availability, the water flow rate to the humidifier wick 5230 may be reduced accordingly. Furthermore, where the water flow rate is d such as where the quantity of water in the reservoir 5110 is limited, the heat output to the humidifier wick 5230 may be reduced ingly.

In a yet further aspect, the humidification thm 5650 may determine target conditions ing to one or more preferences and/or therapeutic requirements of the patient 1000. In one form, the humidification algorithm 5650 may receive a set of patient preferences through input devices 4220. In another form, the humidification thm 5650 may learn a patient’s preference from a usage pattern of the patient 1000 or ion of sleep quality of a patient 1000. .5.3.2.2 Humidifier ation algorithms 5660 In some cases, one or more humidifier calibration algorithms 5660 may be used to verify operation of the humidifier 5000 and/or to calibrate the humidifier 5000. One or more humidifier calibration algorithms may be performed periodically, or according to triggers such as user ts. For instance, an out-of-calibration operation of the fier 5000 may lead to an oversupply of water in comparison to the desired water flow rate, which may lead to introduction of water in the air circuit 4170. Alternatively, an undersupply of water in comparison to the desired water flow rate may lead to overheating of the humidifier 5000 or discomfort for the patient 1000.

In one form, a humidifier calibration algorithm 5660 may deliver a known water flow rate to a humidifier wick 5230, while varying a heat output to the wick 5230 to analyse one or more responses of the humidifier 5000, for example using the humidifier transducers. 505809DIV4 In another form, a humidifier calibration algorithm 5660 may deliver a known heat output to a humidifier wick 5230, while varying a water flow rate to the wick 5230 to analyse one or more responses of the humidifier 5000, for example using the humidifier transducers. .5.3.2.3 Foreign matter management algorithms 5670 As described above, formation, collection and/or build-up on foreign matter such as particulates may occur on the humidifier wick 5230, which may adversely affect a performance of the wick 5230. According to one aspect, one or more foreign matter management algorithms may be used to control the on and/or rate of foreign matter build-up on the wick 5230.

In some cases, foreign matter may t on the humidifier wick at the greatest rate where the wick 5230 dries out completely. For instance, at a water boundary 5230_WB of the water retained by the wick 5230, as shown in Fig. 14. In one form, a foreign matter management algorithm 5670 may manage a on and/or n of a water boundary 5230_WB for example away from an area of detected low water capacity. The foreign matter management algorithm 5670 may achieve this goal by controlling one or more of the heat output onto the humidifier wick 5230, a water flow rate onto the humidifier wick 5230 or a water distribution pattern within the humidifier wick 5230.

According to another aspect, a foreign matter management algorithm may be configured to determine a quality of water, such as a foreign matter content in the water. In one form, a conductivity of water may be ed to determine the foreign matter t in the water. In one form, electrodes in contact with the water may be placed in the humidifier 5000 (e.g. in the reservoir 5110, water delivery mechanism 5150, or in the wick 5230) to measure resistivity of the water. In some forms, the electrodes may be placed in the wick 5230 so that the resistivity measured will te resistivity of the wick and the water n, where a high resistivity may te a corresponding high level of n matter build-up in the wick. 505809DIV4 .5.3.2.4 Wick cleaning algorithms 5680 The humidifier 5000 may comprise wick cleaning algorithms 5680 configured to clean the humidifier wick 5230, for ng the amount of n matter and/or any bio-burden on the wick 5230.

In one form, a wick cleaning algorithm 5680 may operate to rinse the humidifier wick 5230 with a supply of water and/or a cleaning agent. Additionally, or alternatively, the wick cleaning algorithm 5680 may dry the wick 5230, in some cases at a temperature higher than an operating temperature.

In r form, a wick cleaning thm 5680 may be configured to activate where a cleaning adapter is coupled to the humidifier 5000. One advantage of this form may be to prevent use of the humidifier 5000 by the patient 1000 while the wick cleaning algorithm 5680 is activated. In some cases, the cleaning adapter may comprise a ng agent which may be released into the humidifier wick 5230 while the wick cleaning algorithm 5680 is active.

A wick cleaning algorithm 5680 may be configured to operate in some forms after cessation of therapy. In some cases, the RPT device 4000 and/or a humidifier 5000 may be arranged with a battery to enable operation of the wick cleaning algorithm 5680 after power has been switched off. .5.3.3 Patient feedback algorithms 5690 The humidifier 5000 may comprise one or more patient feedback algorithms 5690 for relaying information and/or providing recommendations to the patient 1000.

Patient feedback thms 5690 may, in some forms, inform the patient 1000 of one or more outputs from the humidifier algorithms described above.

Examples of ation provided to a patient 1000 by a patient feedback algorithm 5690 may include a condition of the humidifier wick 5230, such as its ing life or a y of the water, or any anomalous activity of the humidifier 5000, or an indication of a fault, such as detection of a missing water reservoir 5110. In some cases, a patient feedback algorithm 5690 may simply indicate to a patient 1000 or a caregiver that the humidifier wick 5230 may e to be washed. 505809DIV4 .6 GLOSSARY For the purposes of the present technology disclosure, in certain forms of the present technology, one or more of the ing definitions may apply. In other forms of the present technology, alternative definitions may apply. .6.1 General Air: ‘Air’ in the present disclosure will be taken to e breathable gases. In certain forms of the present technology, air supplied to a patient may be atmospheric air, and in other forms of the present technology atmospheric air may be supplemented with oxygen.

Ambient: In n forms of the t technology, the term ambient will be taken to mean (i) external of the treatment system or patient, and (ii) immediately surrounding the treatment system or patient. For example, ambient humidity with t to a humidifier may be the humidity of air immediately surrounding the humidifier.

Continuous Positive Airway Pressure (CPAP): CPAP treatment will be taken to mean the application of a supply of air or air to the entrance to the airways at a pressure that is continuously positive with t to atmosphere, and preferably approximately nt through a respiratory cycle of a patient. In some forms, the pressure at the entrance to the s will vary by a few centimeters of water within a single respiratory cycle, for example being higher during inhalation and lower during exhalation. In some forms, the pressure at the entrance to the airways will be slightly higher during exhalation, and slightly lower during inhalation. In some forms, the pressure will vary between different respiratory cycles of the patient, for e being increased in response to detection of indications of partial upper airway obstruction, and decreased in the absence of tions of partial upper airway obstruction. .6.2 s of RPT devices Air circuit: A conduit or tube constructed and arranged in use to deliver a supply of air between an RPT device and a patient interface. In particular, the air circuit may be in fluid connection with the outlet of the pneumatic block and the patient interface. The air circuit may be referred to as air delivery tube. In some cases 505809DIV4 there may be separate limbs of the circuit for inhalation and exhalation. In other cases a single limb is used. .7 OTHER REMARKS A portion of the sure of this patent document contains material which is subject to copyright protection. The copyright owner has no objection to the facsimile reproduction by anyone of the patent document or the patent disclosure, as it appears in the Patent and Trademark Office patent file or records, but otherwise reserves all copyright rights whatsoever.

Unless the context clearly dictates otherwise and where a range of values is provided, it is understood that each ening value, to the tenth of the unit of the lower limit, between the upper and lower limit of that range, and any other stated or intervening value in that stated range is encompassed within the technology. The upper and lower limits of these ening ranges, which may be independently included in the intervening ranges, are also encompassed within the technology, subject to any specifically excluded limit in the stated range. Where the stated range includes one or both of the limits, ranges excluding either or both of those included limits are also included in the technology. rmore, where a value or values are stated herein as being implemented as part of the technology, it is understood that such values may be approximated, unless otherwise stated, and such values may be utilized to any suitable icant digit to the extent that a practical technical entation may permit or require it.

Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this technology s. gh any methods and materials similar or equivalent to those described herein can also be used in the practice or testing of the t technology, a limited number of the exemplary methods and materials are described .

When a particular material is identified as being preferably used to construct a component, obvious alternative materials with similar properties may be 505809DIV4 used as a substitute. Furthermore, unless specified to the contrary, any and all ents herein described are understood to be capable of being manufactured and, as such, may be manufactured together or separately.

It must be noted that as used herein and in the appended claims, the singular forms "a", "an", and "the" e their plural equivalents, unless the context clearly dictates otherwise.

All ations mentioned herein are incorporated by reference to disclose and describe the methods and/or materials which are the subject of those publications. The publications discussed herein are provided solely for their disclosure prior to the filing date of the present application. Nothing herein is to be construed as an admission that the present technology is not entitled to antedate such publication by virtue of prior invention. Further, the dates of publication provided may be different from the actual publication dates, which may need to be independently confirmed. er, in interpreting the disclosure, all terms should be interpreted in the broadest reasonable manner consistent with the context. In particular, the terms ises" and ising" should be reted as referring to ts, ents, or steps in a non-exclusive manner, indicating that the referenced ts, components, or steps may be present, or utilized, or combined with other elements, components, or steps that are not expressly referenced.

The subject headings used in the ed description are included only for the ease of reference of the reader and should not be used to limit the subject matter found throughout the disclosure or the claims. The subject headings should not be used in uing the scope of the claims or the claim limitations.

Although the technology herein has been described with reference to particular embodiments, it is to be understood that these embodiments are merely illustrative of the principles and applications of the technology. In some instances, the terminology and symbols may imply specific details that are not required to practice the technology. For example, although the terms "first" and "second" may be used, unless otherwise specified, they are not intended to indicate any order but may be utilised to distinguish between distinct elements. Furthermore, although process 505809DIV4 steps in the methodologies may be described or illustrated in an order, such an ordering is not required. Those skilled in the art will recognize that such ordering may be modified and/or aspects f may be conducted concurrently or even synchronously.

It is therefore to be understood that numerous cations may be made to the illustrative embodiments and that other arrangements may be devised without departing from the spirit and scope of the technology. .8 REFERENCE SIGNS LIST patient 1000 bed partner 1100 patient interface 3000 seal-forming structure 3100 plenum chamber 3200 stabilising structure 3300 connection port 3600 ad support 3700 RPT device 4000 external housing 4010 upper portion 4012 lower portion 4014 panel 4015 s 4016 handle 4018 pneumatic block 4020 pneumatic component 4100 air filter 4110 inlet air filter 4112 505809DIV4 outlet air filter 4114 muffler 4120 inlet muffler 4122 outlet muffler 4124 re device 4140 blower 4142 motor 4144 back valve 4160 air circuit 4170 supplemental oxygen 4180 electrical component 4200 PCBA 4202 power supply 4210 input device 4220 central controller 4230 clock 4232 therapy device controller 4240 protection circuit 4250 memory 4260 transducer 4270 pressure transducer 4272 flow transducer 4274 motor speed sensor 4276 data communication interface 4280 remote external communication network 4282 local al communication network 4284 remote external device 4286 505809DIV4 local external device 4288 output device 4290 display driver 4292 display 4294 humidifier 5000 air inlet 5002 air outlet 5004 water reservoir 5110 water volume detector 5112 water delivery mechanism 5150 water pump 5152 water delivery conduit 5154 mechanism 5156 water check valve 5158 humidification chamber 5200 outer housing 5202 outer housing inlet portion 5202a outer housing heater cover portion 5202b outer housing outlet portion 5202c inner g 5204 water feed inlet 5206 air flow baffle 5208 water filter 5214 heating element 5220 oir heating element 5221 humidifier wick 5230 wick dry region 5230_D 505809DIV4 wick wet region 5230_W water boundary 5230_WB wick first layer 5230a wick second layer 5230b wick frame 5232 wick frame grip surface 5232_G wick locator 5233 humidifier filter 5240 bility check algorithm 5260 flow sensor 5512 temperature sensor 5514 humidity sensor 5516 humidifier controller 5550 humidifier thm 5600 wick condition determination algorithm 5610 plausibility check algorithm 5620 pump condition determination algorithm 5630 humidification algorithm 5650 humidifier calibration algorithm 5660 foreign matter management algorithm 5670 wick cleaning algorithm 5680 patient feedback algorithm 5690 example wick condition determination thm 5610A example wick condition determination algorithm step 1 5610A1 example wick ion determination algorithm step 2 5610A2 505809DIV4 example wick condition ination algorithm step 3 5610A3 example wick condition determination algorithm step 4 5610A4 e wick condition determination algorithm step 5 5610A5 example wick condition ination algorithm step 6 5610A6 example wick condition determination algorithm 5610B example wick condition determination algorithm step 1 5610B1 e wick condition determination algorithm step 2 5610B2 e wick condition determination algorithm step 3 5160B3 example wick condition determination algorithm step 4 5160B4 example wick condition determination algorithm step 5 5610B5 example wick condition determination algorithm step 6 5610B6 example wick condition determination algorithm step 7 5610B7 example wick condition determination algorithm 5610C example wick condition determination algorithm step 1 5610C1 e wick condition determination algorithm step 2 5610C2 example wick ion determination algorithm step 3 5610C3 example wick condition determination algorithm step 4 5610C4 example wick condition determination algorithm step 5 5610C5 505809DIV4 example wick condition determination algorithm step 6 5610C6 example wick condition determination algorithm step 7 5610C7 example bility check thm 5620A example plausibility check algorithm step 1 5620A1 example plausibility check algorithm step 2 5620A2 example plausibility check algorithm step 3 5620A3 example plausibility check algorithm step 4 5620A4 example plausibility check algorithm step 5 5620A5 e plausibility check algorithm step 6 5620A6 505809DIV4 6

Claims

1. A method for controlling a location and/or a rate of foreign matter build-up on a humidifier wick of a humidifier, the humidifier comprising the humidifier wick, a heating element to apply heat to the humidifier wick, a water delivery mechanism to deliver water to the humidifier wick, and a controller configured to receive one more signals and/or generate one or more signals, and the humidifier wick being configured to retain a volume of water, the method sing: controlling a location and/or a n of a water boundary on the humidifier wick of the humidifier by varying, with the ller, at least one of: a heat output from the heating element onto the fier wick; a water flow rate from the water delivery ism onto the humidifier wick; and a water distribution pattern within the humidifier wick by ing the heat output from the heating t and/or the water flow rate from the water delivery, wherein controlling the location and/or the pattern of the water boundary causes foreign matter to build up at a predetermined region of the humidifier wick based on the location and/or the pattern of the water boundary.

2. The method as d in claim 1, further comprising: detecting a foreign matter content of the water with a sensor; and determining a quality of the water with the controller based on the foreign matter content detected by the sensor.

3. The method as claimed in claim 2, wherein detecting the foreign matter content of the water with the sensor further comprises measuring a conductivity of the water with the sensor.

4. The method as claimed in claim 2, wherein detecting the foreign matter content of the water with the sensor further ses measuring a resistivity of the water with electrodes in contact with the water.

5. The method as claimed in claim 4, wherein the electrodes are located in the humidifier wick and the water contained in the humidifier wick, and wherein, the resistivity measured by the electrodes is directly correlated to a level of foreign matter build-up in the humidifier wick. 4000 5000 4170 3000