The present invention pertains humidifiers for use in airway pressure support systems for delivering a flow of a humidified gas to the airway of a patient and, more particularly to systems and method for operating pumps in such humidifiers.
Many individuals suffer from disordered breathing during sleep. Sleep apnea is a common example of such sleep disordered breathing suffered by millions of people throughout the world. One type of sleep apnea is obstructive sleep apnea (OSA), which is a condition in which sleep is repeatedly interrupted by an inability to breathe due to an obstruction of the airway, typically the upper airway or pharyngeal area. Obstruction of the airway is generally believed to be due, at least in part, to a general relaxation of the muscles which stabilize the upper airway segment, thereby allowing the tissues to collapse the airway. Another type of sleep apnea syndrome is a central apnea, which is a cessation of respiration due to the absence of respiratory signals from the brain's respiratory center. An apnea condition, whether obstructive, central, or mixed, which is a combination of obstructive and central, is defined as the complete or near cessation of breathing, for example a 90% or greater reduction in peak respiratory air-flow.
Those afflicted with sleep apnea experience sleep fragmentation and complete or nearly complete cessation of ventilation intermittently during sleep with potentially severe degrees of oxyhemoglobin desaturation. These symptoms may be translated clinically into extreme daytime sleepiness, cardiac arrhythmias, pulmonary-artery hypertension, congestive heart failure and/or cognitive dysfunction. Other consequences of sleep apnea include right ventricular dysfunction, carbon dioxide retention during wakefulness, as well as during sleep, and continuous reduced arterial oxygen tension. Sleep apnea sufferers may be at risk for excessive mortality from these factors as well as by an elevated risk for accidents while driving and/or operating potentially dangerous equipment.
Even if a patient does not suffer from a complete or nearly complete obstruction of the airway, it is also known that adverse effects, such as arousals from sleep, can occur where there is only a partial obstruction of the airway. Partial obstruction of the airway typically results in shallow breathing referred to as a hypopnea. A hypopnea is typically defined as a 50% or greater reduction in the peak respiratory air-flow. Other types of sleep disordered breathing include, without limitation, upper airway resistance syndrome (UARS) and vibration of the airway, such as vibration of the pharyngeal wall, commonly referred to as snoring.
It is well known to treat sleep disordered breathing by applying a continuous positive air pressure (CPAP) to the patient's airway. This positive pressure effectively “splints” the airway, thereby maintaining an open passage to the lungs. It is also known to provide a positive pressure therapy in which the pressure of gas delivered to the patient varies with the patient's breathing cycle, or varies with the patient's breathing effort, to increase the comfort to the patient. This pressure support technique is referred to as bi-level pressure support, in which the inspiratory positive airway pressure (IPAP) delivered to the patient is higher than the expiratory positive airway pressure (EPAP). It is further known to provide a positive pressure therapy in which the pressure is automatically adjusted based on the detected conditions of the patient, such as whether the patient is experiencing an apnea and/or hypopnea. This pressure support technique is referred to as an auto-titration type of pressure support, because the pressure support device seeks to provide a pressure to the patient that is only as high as necessary to treat the disordered breathing.
Pressure support therapies as just described involve the placement of a patient interface device including a mask component having a soft, flexible sealing cushion on the face of the patient. The mask component may be, without limitation, a nasal mask that covers the patient's nose, a nasal/oral mask that covers the patient's nose and mouth, or a full face mask that covers the patient's face. Such patient interface devices may also employ other patient contacting components, such as forehead supports, cheek pads and chin pads. The patient interface device is typically secured to the patient's head by a headgear component. The patient interface device is connected to a gas delivery tube or conduit and interfaces the pressure support device with the airway of the patient, so that a flow of breathing gas can be delivered from the pressure/flow generating device to the airway of the patient.
Humidifiers are frequently provided between or integral with a PAP machine and the user interface in order to humidify the otherwise relatively-dry compressed air generated by the PAP machine. Typically, humidifiers can be categorized as heated or passover types.
Heated humidifiers have a built-in heater that raises the temperature of the air being carried between the CPAP machine and the mask. Breathing in cold air can be discomforting and cause a sore throat. Most machines on the market today use a heated humidifier, as they tend to provide comfortable breathing conditions.
Passover type humidifiers are named as such because the air literally “passes over” the water in the humidifier on its journey from the machine to the mask. It wicks the moisture and similar to a heated humidifier, makes the air easier to breath and less irritating to the throat.
Accordingly, it is an object of the present invention to provide an improved humidifier and airway pressure support system including the same.
As one aspect of the disclosed concept, an arrangement for powering a pump in providing a controlled volume of water to a drip nozzle in a drip-feed humidifier is provided. The pump arrangement comprises: a pump having a solenoid; a processing unit; and a power supply electrically connected to the solenoid via a switch which is controlled by the processing unit, the power supply is structured to supply power to the solenoid via the switch, wherein the processing unit is programmed to modulate the power to the solenoid such that the pump is driven at or near a resonant frequency of the pump.
The processing unit may be programmed to modulate the power to the solenoid such that the pump is driven within 5% of the resonant frequency of the pump.
The processing unit may be programmed to modulate the power to the solenoid such that the pump is driven at the resonant frequency of the pump.
The pump may comprise: a diaphragm; an inlet valve; and an outlet valve.
The processing unit may be further programmed to modulate the power to the pump at a lesser level than the resonant frequency during regular operation of the pump.
The processing unit may be programmed to modulate the power to the solenoid such that the pump is driven within 5% of the resonant frequency of the pump.
The processing unit may be programmed to modulate the power to the solenoid such that the pump is driven at the resonant frequency of the pump.
As another aspect of the invention, a method of powering a pump in providing a controlled volume of water to a drip nozzle in a drip-feed humidifier is provided. The method comprises modulating the power to the solenoid such that the pump is driven at or near a resonant frequency of the pump.
Modulating the power to the solenoid may comprise driving the pump within 5% of the resonant frequency of the pump.
Modulating the power to the solenoid may comprise driving the pump at the resonant frequency of the pump.
The pump may comprise: a diaphragm; an inlet valve; and an outlet valve.
The method may further comprise modulating the power to the pump at a lesser level than the resonant frequency during regular operation of the pump.
These and other objects, features, and characteristics of the present invention, as well as the methods of operation and functions of the related elements of structure and the combination of parts and economies of manufacture, will become more apparent upon consideration of the following description and the appended claims with reference to the accompanying drawings, all of which form a part of this specification, wherein like reference numerals designate corresponding parts in the various figures. It is to be expressly understood, however, that the drawings are for the purpose of illustration and description only and are not intended as a definition of the limits of the invention. As used in the specification and in the claims, the singular form of “a”, “an”, and “the” include plural referents unless the context clearly dictates otherwise.
As required, detailed embodiments of the present invention are disclosed herein; however, it is to be understood that the disclosed embodiments are merely exemplary of the invention, which may be embodied in various forms. Therefore, specific structural and functional details disclosed herein are not to be interpreted as limiting, but merely as a basis for the claims and as a representative basis for teaching one skilled in the art to variously employ the present invention in virtually any appropriately detailed structure.
As used herein, the singular form of “a”, “an”, and “the” include plural references unless the context clearly dictates otherwise. As used herein, the statement that two or more parts or components are “coupled” shall mean that the parts are joined or operate together either directly or indirectly, i.e., through one or more intermediate parts or components, so long as a link occurs. As used herein, “directly coupled” means that two elements are directly in contact with each other. As used herein, “fixedly coupled” or “fixed” means that two components are coupled so as to move as one while maintaining a constant orientation relative to each other.
As used herein, the word “unitary” means a component is created as a single piece or unit. That is, a component that includes pieces that are created separately and then coupled together as a unit is not a “unitary” component or body. As used herein, the statement that two or more parts or components “engage” one another shall mean that the parts exert a force against one another either directly or through one or more intermediate parts or components. As used herein, the term “number” shall mean one or an integer greater than one (i.e., a plurality).
Directional phrases used herein, such as, for example and without limitation, top, bottom, left, right, upper, lower, front, back, and derivatives thereof, relate to the orientation of the elements shown in the drawings and are not limiting upon the claims unless expressly recited therein.
Gas flow generator 4 may include, without limitation, ventilators, constant pressure support devices (such as a continuous positive airway pressure device, or CPAP device), variable pressure devices (e.g., BiPAP®, Bi-Flex®, or C-Flex™ devices manufactured and distributed by Philips Respironics of Murrysville, Pa.), and auto-titration pressure support devices. Delivery conduit 6 is structured to communicate the flow of breathing gas from gas flow generator 4 to patient interface device 8. Delivery conduit 6 and patient interface device 8 are often collectively referred to as a patient circuit.
A BiPAP® device is a bi-level device in which the pressure provided to the patient varies with the patient's respiratory cycle, so that a higher pressure is delivered during inspiration than during expiration. An auto-titration pressure support system is a system in which the pressure varies with the condition of the patient, such as whether the patient is snoring or experiencing an apnea or hypopnea. The present invention contemplates that gas flow generator 4 is any conventional system for delivering a flow of gas to an airway of a patient or for elevating a pressure of gas at an airway of the patient, including the pressure support systems summarized above and non-invasive ventilation systems. Although described herein in example embodiments wherein a pressurized flow of gas is utilized, it is to be appreciated that embodiments of the invention as described herein could also be readily employed in other generally non-pressurized applications (e.g., without limitation, in high flow therapy applications).
In the exemplary embodiment, patient interface device 8 includes a patient sealing assembly 16, which in the illustrated embodiment is a full face mask. It is to be appreciated, however, that other types of patient sealing assemblies, such as, without limitation, a nasal/oral mask, a nasal cushion, or any other arrangements which facilitate the delivery of the flow of breathing gas to the airway of a patient may be substituted for patient sealing assembly 16 while remaining within the scope of the present invention. It is also to be appreciated that headgear 10 is provided solely for exemplary purposes and that any suitable headgear arrangement may be employed without varying from the scope of the present invention.
Referring to
Continuing to refer to
Receiving member 134 may include an annular-shaped body portion 156 and a tongue member 160 extending radially outwardly from body portion 156. Furthermore, body portion 156 has an interior facing grooved region 158. As shown in
Nozzle 126 is fluidly connected to water chamber 120 and is configured to produce a water droplet from water 122 received from water chamber 120. More specifically, nozzle 126 has an inlet 150 fluidly connected to water chamber 120 and an opposite outlet 152 from which the water droplet exists nozzle 126. Heater plate 128, which is coupled to wall portion 142, is positioned to receive the water droplet from nozzle 126. In one example embodiment, heater plate 128 is positioned directly below outlet 152, when viewed from the perspective of
The function of pocket 132 will now be discussed in detail in conjunction with
As shown in
More specifically, in operation, planar member 232 minimizes the likelihood that accumulated water from water chamber 220 will be blown into patient interface device 208. Accordingly, planar member 232 advantageously safeguards against the possibility and/or ensures that the phase change of the water droplet from liquid to vapor will occur without a large likelihood of the water droplet being carried off through second end 240 by the velocity component of the breathing gas.
As shown in
As shown in
It will be appreciated that humidifiers 112, 212, and 312 provide different examples of the disclosed concept. Specifically, each of humidifiers 112, 212, and 312 provides a unique mechanism by which water is protected from entering the gas stream and being blown into a corresponding patient interface device 108 and 208 (and the patient interface device of an airway pressure support system including humidifier 312). While the humidifiers 112, 212, and 312 each achieve this aim by virtue of separator features 132, 232, and 332, it will be appreciated that suitable alternative separator features that function to minimize and/or prevent water from entering the gas stream are contemplated herein.
Gas flow generator 404 is configured to pass a flow of breathing gas through conduit 430 and further to patient interface device 408. Nozzle 426 is configured to produce a water droplet from water 422 received from water chamber 420. Heater plate 428, which is coupled to wall portion 442 of conduit 430, and is exposed to interior pathway 444, is positioned to receive the water droplet from nozzle 426. In this manner, when the water droplet evaporates and enters the gas flow stream, humidified breathing gas is able to be delivered to the patient through patient interface device 408.
In accordance with the disclosed concept, humidifier 412, and thus airway pressure support system 402, are further configured to minimize the likelihood that dissolved solids such as, for example and without limitation, calcium, magnesium, potassium, sodium, chlorides, sulfates, along with other organic matter, will be passed from water chamber 420 to pump 424, and/or left behind on heater plate 428 after the water droplets strike heater plate 428 and evaporate into interior pathway 444. For example, while humidifiers for airway pressure support systems are typically recommended to be used with distilled water, users will commonly use commercially available bottled or tap water (e.g., from a well or municipal water system) which may contain unwanted contaminants. While these alternate water types are not recommended for use, and generally do not have a detrimental effect on humidifier operation, they can be problematic for long-term usage of pumps, and generally leave behind the aforementioned contaminants as residue on heater plates. If the amount of residue becomes too great, components of humidifiers will generally have to be replaced. In order to address these concerns, humidifier 412 further includes a filter 433 and optionally a filtration meter 447.
Filter 433 has a housing 435 having an inlet 437 and an opposite outlet 439. Furthermore, housing 435 of filter 433 is structured to house a filtration medium 441 (partially shown in
Filtration medium 441 includes filter elements selected to remove the majority of dissolved solids from water 422 (
Water chamber 420 also provides improved advantages in terms of portability. More specifically, water chamber 420 is configured to collapse from a first (expanded) position, shown in
Referring again to
Mechanism 455 of filtration meter 447 is structured to measure filtration data of the water conveyed through body portion 453. In one example embodiment, mechanism 455 is electrically connected with a processing device (not numbered) of gas flow generator 404 in order to communicate the filtration data to gas flow generator 404. Accordingly, filter 433 and filtration meter 447 cooperate to provide humidifier 412 with a mechanism to remove dissolved solids from water 422 in the event that water 422 is not distilled.
More specifically, after water 422 has passed through filtration medium 441, and exits outlet 439 of filter 433, water 422 enters inlet 449 of filtration meter 447. In one example embodiment, filtration meter 447 is a total dissolved solids meter having two metal probes (e.g., without limitation, copper probes coated with a material, such as gold, to minimize corrosion). The probes may be the same size (e.g., without limitation, 1.5 millimeters in diameter with approximately 2 millimeters of length exposed to the water) and may be placed in parallel at approximately 5 millimeters center to center. As mechanism 455, which contains the probes, is electrically connected with gas flow generator 404, it will be appreciated that the board circuitry of gas flow generator 404 is configured to measure the electrical conductivity between the two probes. The electrical conductivity measurement may be converted to parts per million (hereinafter “PPM”), which provides an indication of the amount of dissolved solids contained in the water passing through filtration meter 447.
In a preferred embodiment, it is to be understood that water passing through filter 433 should have a dissolved solids content of less than 30 PPM. In the event that the dissolved solids measurement by filtration meter 447 is over 30 PPM, the electrical connection between filtration meter 447 and gas flow generator 404 will cause gas flow generator 404 to provide an indication (e.g., a screen reading) to a user that the water quality is too poor (e.g., contains too many dissolved solids), and that the filter needs to be changed. Furthermore, it is contemplated that humidifier 412 may not operate with a dissolved solids content over 30 PPM so as to protect pump 424 and heater plate 428. Furthermore, humidifier 412 is also configured such that once the dissolved solids content of the water reaches 20 PPM, the user will be notified on gas flow generator 404 that the filter is nearing the end of its life and should be replaced soon.
Once water 422 has passed through filtration meter 447, water 422 may flow into pump 424, which generates pressure to move water 422 to nozzle 426. As previously discussed, nozzle 426 is configured to generate the water droplet from water 422, and heater plate 428 is configured to receive the water droplet.
Accordingly, it will be appreciated that airway pressure support system 402 and humidifier 412 for the same are advantageously structured to function with any potable water (e.g., tap, bottled, distilled). Specifically, distilled water generally does not contain problematic dissolved solids, which might otherwise compromise components (e.g., pump 424 and heater plate 428) of humidifier 412. When tap and bottled water are used, while not advisable to users using humidifier 412, the water will advantageously be filtered by filtration medium 441 to remove many dissolved solids before exiting outlet 439. Furthermore, in addition to including filter 433, the failsafe of filtration meter 447 provides the additional advantage of alerting users of the quality of the water exiting outlet 439 of filter 433. That is, while filter 433 is generally configured to remove dissolved solids from the water, the extended use of filter 433 over time may compromise its ability to remove dissolved solids from the water. As such, filtration meter 447 provides a mechanism to address this concern. That is, mechanism 455, as discussed above, is readily configured to alert users of the quality of the water exiting outlet 439 of filter 433. If the quality is not appropriate (e.g., greater than 30 PPM), the user may receive an indication on gas flow generator 404 indicating that filtration medium 441 needs to be replaced. Once filtration medium 441 has been replaced by the user, non-distilled water, although not preferred, will once again be reliably filtered and passed to pump 424 and heater plate 428 with relatively little dissolved solids contained therein. As such, humidifier 412 is versatile in that it is readily configured to be employed with distilled water and non-distilled water without significant concern for compromising the integrity of operating components (e.g., pump 424 and heater plate 428).
Conduit 530 includes a first end 538, a second end 540, a wall portion 542 defining an interior pathway 544 extending between first end 538 and second end 540. Nozzle 526 has an outlet 552 configured to produce a water droplet from water received from the water chamber (not shown). As shown, heater plate 528 has a first side 529 facing nozzle 526 and an opposite second side 531 facing away from nozzle 526. First side 529 is positioned to receive the water droplet from nozzle 526. In one example embodiment, humidifier 512 further includes a number of heating elements 571,573 coupled to second side 531 of heater plate 528. Heating elements 571,573 are configured to heat heater plate 528 in order to cause a water droplet striking first side 529 to evaporate, thereby humidifying the breathing gas.
Additionally, humidifier 512 may further include a thermistor 575 coupled to second side 531 of heater plate 528. Thermistor 575 may be located closer to outlet 552 of nozzle 526 than heating elements 571,573 are located to outlet 552 of nozzle 526. Thermistor 575 may be electrically connected (e.g., via a processing unit) to the gas flow generator of the airway pressure support system including humidifier 512, and allows the processing unit to monitor the temperature of heater plate 528. In this manner, thermistor 575 provides a mechanism to detect whether water droplets exiting outlet 552 are hitting heater plate 528.
Continuing to refer to
It will thus be appreciated that heater plate 528 generally has a centrally located “no heat zone,” depicted most clearly in
Referring to
In the example shown in
A flow chart of an example method 700, which may be carried out according to one particular, non-limiting embodiment of the present invention, which may be carried out by processing device 601 in starting humidifier 612 is shown in
Next, as shown at 708, the temperature of heater plate 628 is raised from generally the temperature of the ambient environment to a first predetermined temperature by a power supply provided to one or more of heating elements 671 and 673. In an example embodiment of the present invention, such first predetermined temperature is about 50° C., although other temperatures may be employed without varying from the scope of the present invention. As previously discussed in regard to the arrangement of
Once the temperature of heater plate 628 has reached the first predetermined temperature, the temperature is held at the first predetermined temperature for a second predetermined period of time, such as shown at 710. In an example embodiment of the present invention such second predetermined period of time is 10 seconds, although other time increments may be employed without varying from the scope of the present invention. Once the second predetermined period of time has elapsed, a countdown timer counting down from a predetermined countdown time is started, as shown at 712, and a sufficient power is supplied to pump 624 so as to begin operating pump 624 at a first predetermined duty cycle, such as shown at 714. In an example embodiment of the present invention, such first predetermined duty cycle is about a 20% duty cycle, although other suitable duty cycles may be employed without varying from the scope of the present invention. In an example embodiment of the present invention, the countdown timer is set for five minutes, although other time periods may be utilized without varying from the scope of the present invention.
Once pump 624 begins operating at 714, the temperature of heater plate 628 is monitored (via thermistor 675), as shown at 716. As shown in 718 and 720, such monitoring continues until either a drop in temperature is detected or until the countdown timer reaches zero. If the countdown timer reaches zero at 720 before a temperature drop is detected in 718, thus indicating that no water has struck heater plate 628 (due to lack of water in water chamber 620, failed pump, a blockage somewhere between water chamber 620 and nozzle 626, or some other problem) then pump 624 is turned off, as shown as 722, as well as heater elements 671 and 673, as shown at 724. Optionally, a signal or message may be provided to the patient via any suitable means to indicate that the humidifier has shut off. Alternatively, if a drop in temperature is detected at 718 before the countdown timer reaches zero, thus indicating that a water droplet or droplets have struck heater plate 628 (i.e., temperature of heater plate drops slightly due to vaporization of water droplets striking plate), the duty cycle of pump 624 is increased at 728 to a predetermined second duty cycle after waiting for a third predetermined period of time, such as shown at 726. In an example embodiment of the present invention, such second duty cycle is about a 25% duty cycle, although other suitable duty cycles may be employed without varying from the scope of the present invention. In an example embodiment of the present invention such third predetermined period of time is twenty seconds, although other suitable time increments may be employed without varying from the scope of the present invention.
After increasing the pump duty cycle at 728, the temperature of heater plate 628 is increased to about a second predetermined temperature (which coincides with a normal operating temperature) as shown at 730. In an example embodiment of the present invention, such second predetermined temperature is about 120° C., although other suitable temperatures may be employed without varying from the scope of the present invention. After reaching the second predetermined temperature, the humidifier continues on with normal operation. From the foregoing it is thus to be appreciated that method 700 provides a startup mechanism that keeps the heater plate from being fully powered until it is verified that water is being delivered to the heater plate. Additionally, by wetting the heater plate at a low temperature, any solids (from impurities in water provided in the water chamber) which have been previously deposited on the heater plate do not break up and release into the airstream. Hence, such method also reduces/eliminates the release of obnoxious gas which can otherwise be released from such solids.
Power profile 802 extends between a pump volume range 804, which corresponds to movement of armature 696 from a starting to a fully extended position, and a total extension time 806, which in the example shown in
A solenoid driven pump, such as pump 624 of
In the claims, any reference signs placed between parentheses shall not be construed as limiting the claim. The word “comprising” or “including” does not exclude the presence of elements or steps other than those listed in a claim. In a device claim enumerating several means, several of these means may be embodied by one and the same item of hardware. The word “a” or “an” preceding an element does not exclude the presence of a plurality of such elements. In any device claim enumerating several means, several of these means may be embodied by one and the same item of hardware. The mere fact that certain elements are recited in mutually different dependent claims does not indicate that these elements cannot be used in combination.
Although the invention has been described in detail for the purpose of illustration based on what is currently considered to be the most practical and preferred embodiments, it is to be understood that such detail is solely for that purpose and that the invention is not limited to the disclosed embodiments, but, on the contrary, is intended to cover modifications and equivalent arrangements that are within the spirit and scope of the appended claims. For example, it is to be understood that the present invention contemplates that, to the extent possible, one or more features of any embodiment can be combined with one or more features of any other embodiment.
This application is a continuation of U.S. patent application Ser. No. 16/225,309, filed on Dec. 19, 2018, which claims the benefit of U.S. Provisional Application No. 62/611,557, filed on 29 Dec. 2017. This application is hereby incorporated by reference herein.
Number | Date | Country | |
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62611557 | Dec 2017 | US |
Number | Date | Country | |
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Parent | 16225309 | Dec 2018 | US |
Child | 17667865 | US |