Patent Application
20070295328
The invention will be described by way of example and with reference to the accompanying drawings in which:
With reference to
On the upper portion or top 5 of the primary chamber 4 is a medicant chamber 8. The medicant chamber 8 has a movable end closure or valve 9 which when opened provides a passage for the medicant dosage 100 to enter the primary chamber 4. Typically the dosage is very small, usually substantially less than 1 milligram, typically 50 to 200 micrograms. As shown in
A pump means 30 is connected to the primary chamber 4. The pump means 30 has a one way check valve 32 such as a solenoid valve between the pump 31 connection and the primary chamber 4 connection. By depressing a first switch 40 the pump 31 is activated which evacuates some of the air 22 and water vapor 20A mixture of the primary chamber 4 from an initial pressure P0 of ambient or about 14.7 psi to a reduced pressure P1 of less than P0, the pressure P1 being preferably less than 12 psi or between 12 and 7 psi typically, thereafter the ultrasonic transducer 12 is activated for a predetermined time (t1) as shown in
The movement of the air 22 and water vapor 20A across the valve 32 creates a drop in temperature due in part to the Joule-Thompson Effect. The primary chamber air temperature T0 was initially at ambient and as the pressure drops the temperature correspondingly drops to T1. This is as one would anticipate under the normal equations for a perfect gas PV=rT. A drop in pressure from P0 to P1 while the volume remains constant results in a change in temperature from T0 (ambient) to T1 (less than ambient).
After the pump means 30 shuts down a second switch 42 automatically or by a manual activation opens the valve or end closure 9 on the medicament dispenser chamber 8 as shown in
As illustrated the cloud 200 can be visible through the primary chamber 4 which is preferably made of a clear plastic material.
A mouthpiece connector 52 is connected to the primary chamber 4. Flap 51 is attached inside the lumen of passageway 54 in an expanded area mouthpiece connector 52 and abuts against a reduced diameter stop 53 to seal the opening during evacuation. As the chamber 4 is already rarefied and filled with water vapor, conditions are satisfied to form a cloud immediately after seeding with the cloud forming powder dosage 100. Along with the entry of the dosage 100, air enters through the vent passage 56 and enters the chamber 4 and the chamber pressure rises to atmospheric allowing the patient to suck on the tubing 60 to unseal the flap 51. Additionally, a vent passage 56 to ambient air located on the cap closure 11 is opened when the end closure or valve 9 opens allowing ambient air to re-enter the primary chamber 4. Accordingly as the patient breathes inhaling the cloud 200 ambient air 22 is allowed into the chamber 4 through the vent opening 56 filling the volume as the cloud 200 is withdrawn and inspired into the patients lungs.
The cloud 200 laden with the dose 100 of medicine is easily transferred with 1 or 2 breaths and thus is received as a bolus inhalation into the lungs. Virtually all of the medicine transfers as the cloud formation 200 insures the medication dosage 100 stays suspended in the very tiny droplets 202 of a size substantially smaller than 120 microns, typically having an average size in the 2 to less than 10 micron size.
The invention as disclosed creates a vapor-rich environment suitable for cloud formation without requiring a separate heating element or a cooling coil to enhance cloud formation.
By using the thermodynamic principles of the ideal or perfect gas law the change in lowering or reduced pressure correspondingly creates a change in temperature lower the temperature of the gases in the primary chamber while the mist of water vapor is being generated by the ultrasonic transducer. As the medication in a fine powder form is dispersed into the water vapor-rich air mixture, the water vapor molecules 20A attach to individual particles of medicine 100 forming the cloud 200 of extremely small size medicine laden water droplets 202 ideally suited for inhalation deep into the lungs. The seeding of the cloud by the introduction of fine powder particles adds mass to the system which correspondingly further reduces the temperature slightly.
This technique avoids the use of heating elements or cooling coils to facilitate the formation of a mist. As can be equally appreciated the use of these added components not only increased cost but were in fact sources of errors in that improper temperature controls or settings actually could render the equipment less efficient causing large percentages of a medication dosage to be condensed into droplets that would adhere to the container or chamber walls without ever reaching the patient. As such a doctor could never be sure if the patient ever received a sufficient amount of the medication.
The present invention by operating in a temperature range closer to room temperature avoids these condensation issues while still providing a suitable environment for cloud formation.
As shown the nebulizer 10 can be formed of two separate chambers, an upper primary chamber 4 and a lower secondary chamber 8. The two chambers are attached by a hinge 70 pivotable about the hinge pin 72. On the opposite side of the hinge a means 74 for closing the nebulizer 10 is shown. The means 74 is attached to the upper chamber 4 by a fastener 77 and securely slips over an attachment pin 76 as shown. An O ring type seal 80 is positioned in a groove on top of the secondary chamber 6 and upon attaching the means 74 for closing the nebulizer forms an airtight seal between the chamber 4 and chamber 6 as shown. This provides for a simple yet efficient way to open and wipe clean the nebulizer 10 after each use.
As further shown the nebulizer preferably has rubber pads 90 on the bottom of the lower secondary chamber 6. These pads 90 keep the nebulizer 10 from vibrating on a hard surface and thus prevent movement and reduced noise.
As shown in the
Similarly the one way check valve 32 can be replaced with a one way solenoid valve 32 and a timer (not shown) which after a predetermined time to evacuate the chamber 4 can be used to activate the switch 42 to automatically open the movable end closure or valve 9 to seed the cloud thereby eliminating the need to manually activate the switch 42.
Although not show it is understood that and is preferable that the nebulizer 10 is powered using batteries that are preferably rechargeable or can be electrically connected to an electrical outlet plug by a cord if so desired. In another alternative construction the end closure 9 may be spring loaded to snap open when the pressure differential of the evacuated chamber meets a required amount. In this case the transducer 12 must be activated sufficiently quickly prior to the pump 30 reaching the evacuated pressure needed to have the spring snaps open. Once opened the end closure 9 must be manually reset to the closed positioned after being used and prior to being reused.
Variations in the present invention are possible in light of the description of it provided herein. While certain representative embodiments and details have been shown for the purpose of illustrating the subject invention, it will be apparent to those skilled in this art that various changes and modifications can be made therein without departing from the scope of the subject invention. It is, therefore, to be understood that changes can be made in the particular embodiments described which will be within the full intended scope of the invention as defined by the following appended claims.
