Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B05—SPRAYING OR ATOMISING IN GENERAL; APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
  • B05B—SPRAYING APPARATUS; ATOMISING APPARATUS; NOZZLES
  • B05B17/00—Apparatus for spraying or atomising liquids or other fluent materials, not covered by the preceding groups
  • B05B17/04—Apparatus for spraying or atomising liquids or other fluent materials, not covered by the preceding groups operating with special methods
  • B05B17/06—Apparatus for spraying or atomising liquids or other fluent materials, not covered by the preceding groups operating with special methods using ultrasonic or other kinds of vibrations
  • B05B17/0607—Apparatus for spraying or atomising liquids or other fluent materials, not covered by the preceding groups operating with special methods using ultrasonic or other kinds of vibrations generated by electrical means, e.g. piezoelectric transducers
  • B05B17/0653—Details
  • B05B17/0669—Excitation frequencies
• • A—HUMAN NECESSITIES
  • A24—TOBACCO; CIGARS; CIGARETTES; SIMULATED SMOKING DEVICES; SMOKERS' REQUISITES
  • A24F—SMOKERS' REQUISITES; MATCH BOXES; SIMULATED SMOKING DEVICES
  • A24F40/00—Electrically operated smoking devices; Component parts thereof; Manufacture thereof; Maintenance or testing thereof; Charging means specially adapted therefor
  • A24F40/05—Devices without heating means
• • A—HUMAN NECESSITIES
  • A24—TOBACCO; CIGARS; CIGARETTES; SIMULATED SMOKING DEVICES; SMOKERS' REQUISITES
  • A24F—SMOKERS' REQUISITES; MATCH BOXES; SIMULATED SMOKING DEVICES
  • A24F40/00—Electrically operated smoking devices; Component parts thereof; Manufacture thereof; Maintenance or testing thereof; Charging means specially adapted therefor
  • A24F40/40—Constructional details, e.g. connection of cartridges and battery parts
• • A—HUMAN NECESSITIES
  • A24—TOBACCO; CIGARS; CIGARETTES; SIMULATED SMOKING DEVICES; SMOKERS' REQUISITES
  • A24F—SMOKERS' REQUISITES; MATCH BOXES; SIMULATED SMOKING DEVICES
  • A24F40/00—Electrically operated smoking devices; Component parts thereof; Manufacture thereof; Maintenance or testing thereof; Charging means specially adapted therefor
  • A24F40/50—Control or monitoring
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61M—DEVICES FOR INTRODUCING MEDIA INTO, OR ONTO, THE BODY; DEVICES FOR TRANSDUCING BODY MEDIA OR FOR TAKING MEDIA FROM THE BODY; DEVICES FOR PRODUCING OR ENDING SLEEP OR STUPOR
  • A61M15/00—Inhalators
  • A61M15/0065—Inhalators with dosage or measuring devices
  • A61M15/0066—Inhalators with dosage or measuring devices with means for varying the dose size
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B05—SPRAYING OR ATOMISING IN GENERAL; APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
  • B05B—SPRAYING APPARATUS; ATOMISING APPARATUS; NOZZLES
  • B05B12/00—Arrangements for controlling delivery; Arrangements for controlling the spray area
  • B05B12/08—Arrangements for controlling delivery; Arrangements for controlling the spray area responsive to condition of liquid or other fluent material to be discharged, of ambient medium or of target ; responsive to condition of spray devices or of supply means, e.g. pipes, pumps or their drive means
  • B05B12/12—Arrangements for controlling delivery; Arrangements for controlling the spray area responsive to condition of liquid or other fluent material to be discharged, of ambient medium or of target ; responsive to condition of spray devices or of supply means, e.g. pipes, pumps or their drive means responsive to conditions of ambient medium or target, e.g. humidity, temperature position or movement of the target relative to the spray apparatus
• • A—HUMAN NECESSITIES
  • A24—TOBACCO; CIGARS; CIGARETTES; SIMULATED SMOKING DEVICES; SMOKERS' REQUISITES
  • A24F—SMOKERS' REQUISITES; MATCH BOXES; SIMULATED SMOKING DEVICES
  • A24F40/00—Electrically operated smoking devices; Component parts thereof; Manufacture thereof; Maintenance or testing thereof; Charging means specially adapted therefor
  • A24F40/10—Devices using liquid inhalable precursors
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61M—DEVICES FOR INTRODUCING MEDIA INTO, OR ONTO, THE BODY; DEVICES FOR TRANSDUCING BODY MEDIA OR FOR TAKING MEDIA FROM THE BODY; DEVICES FOR PRODUCING OR ENDING SLEEP OR STUPOR
  • A61M15/00—Inhalators
  • A61M15/0085—Inhalators using ultrasonics
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61M—DEVICES FOR INTRODUCING MEDIA INTO, OR ONTO, THE BODY; DEVICES FOR TRANSDUCING BODY MEDIA OR FOR TAKING MEDIA FROM THE BODY; DEVICES FOR PRODUCING OR ENDING SLEEP OR STUPOR
  • A61M16/00—Devices for influencing the respiratory system of patients by gas treatment, e.g. ventilators; Tracheal tubes
  • A61M16/0003—Accessories therefor, e.g. sensors, vibrators, negative pressure
  • A61M2016/0015—Accessories therefor, e.g. sensors, vibrators, negative pressure inhalation detectors
  • A61M2016/0018—Accessories therefor, e.g. sensors, vibrators, negative pressure inhalation detectors electrical
  • A61M2016/0021—Accessories therefor, e.g. sensors, vibrators, negative pressure inhalation detectors electrical with a proportional output signal, e.g. from a thermistor
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61M—DEVICES FOR INTRODUCING MEDIA INTO, OR ONTO, THE BODY; DEVICES FOR TRANSDUCING BODY MEDIA OR FOR TAKING MEDIA FROM THE BODY; DEVICES FOR PRODUCING OR ENDING SLEEP OR STUPOR
  • A61M16/00—Devices for influencing the respiratory system of patients by gas treatment, e.g. ventilators; Tracheal tubes
  • A61M16/0003—Accessories therefor, e.g. sensors, vibrators, negative pressure
  • A61M2016/003—Accessories therefor, e.g. sensors, vibrators, negative pressure with a flowmeter
  • A61M2016/0033—Accessories therefor, e.g. sensors, vibrators, negative pressure with a flowmeter electrical

Definitions

• US2012186594 describes using a sensor to sense both the flow direction and rate of inhaled air. This sensor signal is used to determine when the air flow is in the right direction and exceeds a set threshold rate so as to trigger smoke generation.
• a spray delivery device for delivering a fluid spray to a fluid flow conductor, comprising: a spray generator, a spray controller; and an air flow sensor; wherein the spray generator comprises a perforate membrane and actuation means configured to ultrasonically vibrate the perforate membrane in response to a drive signal from the spray controller, such that vibration of the perforate membrane causes liquid droplets to be ejected from an ejection side of the perforate membrane; and wherein the flow sensor is configured to provide a flow signal representative of an air flow rate through the flow conductor, such that the spray controller can modulate a spray rate of the spray generator in response to the sensed air flow rate.
• the spray controller may be configured to generate no spray when the sensed air flow is below a predetermined threshold value.
• the spray controller may be configured to modulate the drive signal by shifting a frequency of the drive signal away from the resonant frequency of the device, such that for the same drive signal amplitude, a lower power is delivered by the spray generator.
• the spray controller may be configured to modulate the drive signal by adjusting the mark space ratio of the drive signal.
• the spray controller may be configured to adjust the mark space ratio of the drive signal such that the spray head drive is switched on and off at a frequency lower than the resonant drive frequency.
• the spray controller may be configured to multiply the flow signal by a
• the device may be configured to permit a user to change the proportionality constant, k.
• the device may be configured to adapt the proportionality constant, k, such that a defined dose is delivered substantially evenly within a predefined sub-portion of the user's total inhalation time.
• the invention further provides an inhalation device comprising a spray delivery device according to any of the preceding claims, wherein the spray delivery device is configured to deliver the fluid spray to a fluid flow path through a body of the inhalation device.
• formulations or may be an electronic cigarette may be an electronic cigarette.
• the invention further provides a device for delivering a fluid spray to a mouth of a user, either directly, or via a flow conductor such as a tube or pipe, the device comprising a vibratable perforate membrane for generating the spray, wherein the device is configured to control the vibration of the membrane in response to input from a flow rate sensor which detects a flow rate through the device or through the flow conductor.
• the invention further provides a method of controlling a spray head in a spray delivery device, the spray head comprising a vibratable perforate membrane for generating a spray, the method comprising receiving a sensed air flow signal representative of an air flow rate through a flow conductor to which the spray head is arranged to deliver a spray, and modulating a spray rate of the spray generator in response to the sensed air flow signal.
• Figure 2 illustrates a first sensor signal and corresponding membrane drive signal for implementation in an embodiment of the invention
• Figure 3 illustrates a second sensor signal and corresponding membrane drive signal for implementation in an embodiment of the invention
• Figure 5 illustrates a further mark space moderator signal and sensor signal for implementation in an embodiment of the invention
• Figure 6 illustrates a sensor signal and corresponding drive signal for implementation in an embodiment of the invention.
• Figure 7 illustrates a further example of a sensor signal and a corresponding drive signal for implementation in an embodiment of the invention. Detailed Description of Embodiments of the Invention
• FIG. 1 A shows a schematic representation of an inhalation device according to an embodiment of the invention.
• the device has means to sense the inhaled airflow rate, preferably provided through the combination of the flow restrictor provide by opening (1) serving as a pressure restriction.
• the opening is typically of a cross sectional area of 6 to 12 mm 2 and the pressure sensor (2), preferably mounted on a PCB (3).
• the combination of the mouthpiece (7) and body (9) may form an otherwise sealed chamber with the exception of the opening (1) and the opening of the mouthpiece (7).
• the signal from the pressure sensor (2) is connected to and measured by the controller (microcontroller) (4).
• the flow rate of air is calculated by the controller (4) and the appropriate delivery rate of fluid into the flow passing through the inhaler is determined for the measured inhalation rate.
• the controller then generates a drive signal to drive the atomising head (6). Variation of the drive signal allows adaption of the delivery rate to the inhalation rate by the means described in relation to figures 2 to 7.
• the controller (4) and PCB (3) are supplied with energy from the battery (8).
• the drive signal generated by the controller (4) is supplied to the perforate membrane based resonant atomising head (6) which in turn is mounted in a fluid reservoir (5).
• the resonant atomising head itself will typically consist of a PZT ceramic actuator bonded to a metallic substrate such that when the actuator is excited by an appropriate frequency alternating signal will vibrate and induce vibration in the perforate membrane.
• FIG. 1 B An example of such an arrangement is shown in Figure 1 B.
• the flow conductor (20) has a flow sensor (10) such as that produced by Honywell S&C part number AWM720P1.
• This flow sensor provides a signal that is fed into the spray device (17) where the device, preferably on a daughter board (14), processes the flow signal to control the delivery of the spray.
• the drive PCB (13) and battery (16) in turn supply the necessary drive signal to the spray head (19), which delivers droplets at the appropriate rate from the fluid reservoir (18).
• the droplets are fed into the air stream in the flow conductor (20) via the port (12).
• Any of the drive methods discussed in the following can of course be used in either of the devices of Figures 1 A and 1 B.
• Tuning the drive signal to the actuator can be achieved by a spray controller scanning a pre-programmed frequency band before commencing spraying, and using the results of this scan to record the resonant frequency of the spray generator and to use it as a later reference frequency.
• the resonant frequency can be periodically checked by the controller whilst spraying so as to capture any shifts in resonant frequency due to changes in liquid loading for example.
• a self-resonant drive circuit can be used in which the spray generator forms part of a resonant circuit such that the drive signal frequency is automatically tuned to the resonant frequency of the head.
• Typical applications that can benefit from adjusting the fluid flow or delivery rate in response to a variable parameter include: matching the fluid delivery rate to a flow rate of a gas stream, in the case of dosing the gas stream with an additional fluid, for example adding water droplets to allow control of humidity of a gas stream once the droplets evaporate; and adding anaesthetic agents to a gas stream in proportion to a flow rate of the gas.
• the flow rate could be proportional to the inhalation rate, optionally subject to a minimum trigger level below which delivery is not started.
• the amplitude of vibration is affected by how close frequency of stimulation is to the resonant frequency of the device. Adjusting the drive frequency to be slightly off the resonant frequency, for example by being offset from the resonant frequency by amounts such as 500 Hz to a few KHz away from the true resonant frequency.
• the degree of flow rate attenuation for a given offset from resonance allows the control of flow rate to be achieved and can therefore provide a second way in which to control the vibration and hence flow rate from such spray generators.
• This method has the advantage of using largely the same electronic components as those needed for basic driving of the spray generator, rather than needing additional components to adjust the drive voltage.
• time-based modulation of the drive signal which we shall call "duty cycling”.
• duty cycling For pressurised sprays in industrial environments, pulsing of the spray by turning a valve on and off rapidly is used to adjust flow rate by such time- based modulation. This is commonly referred to as pulse width modulation.
• flow rate is linearly proportional to on-time, thus a reduction in duty cycle from 100% (constantly on) to 50% (on half the time) would approximately halve the flow rate.
• the controller of figure 1 can therefore be configured to implement such a time-based modulation of the drive signal for the device of figure 1.
• Delivery rate k x inhalation rate where k is the proportionality factor. If k is increased, the dose rate, or fluid delivery rate, for a given inhalation rate will increase and vice versa.
• a similar technique could be used to gradually reduce the dose over time, through an inbuilt algorithm provided in the spray controller, by reducing the value of k so that the user's dose could be gradually reduced, either during a single inhalation, or over multiple inhalations over an extended period of time.
• the appearance of continuous delivery generally requires the overall period of the duty cycle, or otherwise stated, the time between each instance of the modulation signal switching from off to on, to be less than approximately 30 milliseconds, more ideally, less than 15 milliseconds.
• the acceptable limits for switching can have longer on and off periods, as mixing within the gas stream will average out the concentration and, further, the delivery will not be directly visible to the user. Therefore, the appearance of the delivery is less important. Given that a typical breath may be 2 seconds long, to provide the effect of proportional control, the rate at which changes can be made to the delivery rate is important.
• the fluid delivery rate can also be adapted such that the total on-time within the user's typical inhalation time is sufficient to deliver a specific dose.
• the drive sequence for modulating the drive signal to create the desired fluid delivery rate can be iteratively adapted over a sequence of inhalation profiles. If the controller records the duration and total air volume of one or more successive inhalation events, the controller can establish a nominal inhalation duration and air volume for one or more of the recorded inhalation events.
• the controller can determine a proportionality constant K, such that the rate of delivery is tuned to be completed within the expected inhalation event. For example if the user typically inhales 2 litres of air in a 2 second inhalation and the set dose volume is 15 microlitres then an appropriate K value can be calculated. For simplicity if the inhalation rate is assumed to be constant for the two seconds and the delivery rate is similarly assumed to be constant for the delivery duration the delivery rate would be 7.5 microlitres per second and : catalog inhalation rate
• the controller can tune the actual delivery rate to suit the inhalation rate which will in practice vary through the inhalation. Increasing K by a few percent will ensure that the dose is delivered before the end of the inhalation.
• By successively adjusting the K value in this way over inhalation events allows tuning of the delivery to the anticipated inhalation profile for the user. This can all act to refine the delivery profile, such that the dose is delivered in a desired manner during a typical inhalation of a user.
• the chosen profile may be set to deliver the fluid evenly over the user's typical inhalation time.
• the profile may alternatively be adapted such that the fluid delivery is targeted for a particular sub-section of the user's typical inhalation, for example to ensure delivery to the deep lung by increasing the K value to ensure that the dose is delivered before the end of the inhalation event
• the performance of the overall system can be optimised.
• the dosing rate can be controlled to stay within tolerable limits or to optimise the delivery rate to suit the inhalation rate. This can be useful in the case of delivering a drug to patients with a low inspiration flow such as COPD [Chronic obstructive pulmonary disease] patients or children where the maximum delivery rate can be overwhelming.
• COPD Choronic obstructive pulmonary disease
• users have a preference for the delivery rate to be in proportion to the inhalation rate. Expressed simply, the harder the user inhales the greater the delivery rate.
• the use of a pressure restriction and a pressure sensor can be used to create a measure of breath inhalation rate.
• the inhalation rate can be measured and used to provide a signal to control the delivery rate.
• Figure 2 illustrates an example of the modulation of a drive signal by the spray controller of the invention in response to a measured flow signal coming from the flow sensor of the device.
• the figure shows moderation of a sinusoidal drive signal, such as may be used for driving an ultrasonic actuator of the device of Figure 1 , in response to a demand signal shown as a linearly rising signal.
• Typical drive frequencies for the ultrasonic spray generator may be in the range 30kHz to 200 kHz and more typically in the range 50 to 120 kHz. For clarity the drive signal is not shown with its real frequency in this figure.
• Figure 2 also illustrates a deferred reaction to the demand signal, such that the drive signal is only initiated by the spray controller once the demand signal reaches a particular trigger threshold.
• typical value for the trigger threshold is 10 to 15 litres per minute. This serves as a good compromise between wanting the delivery to start early in the inhalation and providing a sufficiently robust sensor value to trigger, avoiding false triggering due to sensor signal noise or air movements due to factors other than inhalation occurring.
• the time for inhalation rates to reach 10 or 15 litres per minute at the start of an inhalation is typically 0.1 seconds or sometimes shorter, this trigger level makes good use of the available inhaled volume. This has the advantage of avoiding false triggering events and also, in the case of amplitude modulation, prevents trying to drive the spray head with too low a voltage for effective operation.
• Figure 3 shows a similar arrangement, preferably where the demand signal is representative of an inhalation through a relatively high resistance drug delivery device, such as an inhaler or electronic cigarette.
• This implementation will tend to give a longer duration of an inhalation, such as the 2 seconds or thereabouts shown in the Figure.
• the drive signal is moderated in amplitude in proportion to the demand signal, which is the output of the flow sensor, and there is a defined minimum threshold trigger level, below which the drive signal is not initiated, which threshold may be at any of the values described above.
• Figure 5 shows a similar arrangement, where the demand is higher and so the mark space ratio for the drive signal is higher.
• the graph shows the sensor or demand signal and the drive signal being on for approximately 8 ms and off for approximately 2 ms, an 80% duty cycle. Varying the duty cycle in this way has been shown to alter the delivery rate linearly with respect to the mark space ratio.
• Figure 6 shows mark space modulation of the drive signal in response to a demand signal that is increasing linearly.
• the mark space ratio increases in a linear fashion in response to the rising sensor signal value and so matches the delivery rate to the demand.
• the period of switching that set the duration of the on and off periods can be set to choice as discussed above, so typically for an inhalation device the switching period may be set to 15ms and hence a 1 :1 mark space ratio would result in driving the head for 7.5ms and not driving the head for 7.5ms. Similarly for a 75 litre per minute air flow the mark space ratio would be 3:4 and the on time would be 11.25ms and the off time would be 3.75 ms within a switching period.
• the flow signal is 0.25 (25%) of full scale value set for the controller.
• the switching period has been set to 15ms, so that the on time is 20% of 15 ms, so 3 ms, and the off time is 12 ms.
• the switching period has set at 10 ms and the sensed flow rate is 90% of the maximum expected values. Hence the on time is 9ms and the off time is 1ms.
• Figure 7 the configuration is similar to that of Figure 6.
• the average measured flow rate in a switching period is determined and this is used to set the mark space ratio.
• the average flow rate is 30% of the maximum and so the on time is 30 % of the switching period (3 ms) and the off time is 70% of the switching period (7 ms).
• the average measured flow is 80% of maximum and so the on time 8ms (80% of the switching period) and the off time is 2ms.

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• Health & Medical Sciences (AREA)
• Engineering & Computer Science (AREA)
• Life Sciences & Earth Sciences (AREA)
• Heart & Thoracic Surgery (AREA)
• Animal Behavior & Ethology (AREA)
• Pulmonology (AREA)
• Anesthesiology (AREA)
• Biomedical Technology (AREA)
• Veterinary Medicine (AREA)
• Hematology (AREA)
• Bioinformatics & Cheminformatics (AREA)
• General Health & Medical Sciences (AREA)
• Public Health (AREA)
• Biophysics (AREA)
• Special Spraying Apparatus (AREA)
• Medicinal Preparation (AREA)
• Nozzles (AREA)
• Media Introduction/Drainage Providing Device (AREA)

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Cited By (25)

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• 2015
  • 2015-06-11 GB GBGB1510166.0A patent/GB201510166D0/en not_active Ceased
• 2016
  • 2016-06-10 CN CN201680043696.3A patent/CN108472460A/zh active Pending
  • 2016-06-10 WO PCT/GB2016/051712 patent/WO2016198879A1/en not_active Ceased
  • 2016-06-10 JP JP2017564644A patent/JP2018521739A/ja active Pending
  • 2016-06-10 US US15/735,078 patent/US20200046918A1/en not_active Abandoned
  • 2016-06-10 EP EP16741105.7A patent/EP3307366B1/en active Active

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