One of the applications of a microfluidic ejection device is to jet a solution on to another device where a secondary function may be performed. A common secondary function is to vaporize a solution using a heater such that the contents of the solution can be vaporized so as to deliver the solution as a gaseous substance. Applications of such technology include, but are not limited to, metering and vaporizing device for electronic cigarettes, vapor therapy, gaseous pharmaceutical delivery, vapor phase reactions for micro-labs, and the like. This document discloses a method for integrating the fluid delivery and vaporization mechanisms into a single microfluidic device for the purposes of further miniaturization, higher precision vapor delivery and cost reduction, as well as operational efficiency.
When jetting a fluid onto a heated surface it is highly desirable for 100% of the fluid to vaporize so that liquid is not discharged from the vaporizing device. The problem lies in that the vaporizing heater must be small enough to heat up extremely quickly, but yet have enough surface area to catch all fluid and fluid droplets that is being ejected onto it. In a conventional vaporizing device, a fluid wick would be used that would be disposed in a fluid reservoir on one end thereof while touching a heater on a distal end thereof to vaporize fluid wicked from the fluid reservoir. The wick method has no control of how much fluid is vaporized. Thus the amount of fluid vaporized may vary with the amount of negative pressure applied to the vaporizing device. If a conventional heater configuration for vaporizing fluids is used for providing a jetted fluid, the entire wick is heated to the high temperature. Heating the entire wick requires a large amount of energy and may result in degradation of the wick over time.
Another problem with conventional vaporizing devices is that a standard back pressure range is preferred in vaporizing devices to prevent liquid from drooling from the ejection head. A back pressure of about 7 to about 12 kilonewtons per square meter is desirable. However, if a conventional jetting device for the fluid is exposed to a negative pressure the ejection head will begin to drool and not accurately jet fluid therefrom. Accordingly, what is needed is a fluid vaporizing assembly that provides a sufficient back-pressure for vapor applications yet provides a controlled amount of liquid to be vaporized.
In view of the foregoing, one embodiment of the disclosure provides a heater assembly for a vaporizing device, a vaporizing device containing the heater assembly, and a method for vaporizing fluid ejected by an ejection head. The heater assembly for the vaporizing device includes a vapor inlet end and a vapor outlet end, positive and negative electrodes for contact with positive and negative heater terminals on a vaporizing heater, an insulator for electrical insulation between the positive and negative heater terminals, and a wick disposed between the insulator and the vaporizing heater for dispersion of liquid to be vaporized by the vaporizing heater and for back pressure control of the vaporizing device.
Another embodiment of the disclosure provides a vaporizing device that includes a housing body, a mouthpiece attached to the housing body, a heater assembly disposed in the mouthpiece for vaporizing fluid ejected from an ejection head, and a removable fluid ejection assembly attached to the mouthpiece. The fluid ejection assembly includes a fluid container in flow communication with the ejection head. The heater assembly includes a heater element having a fluid collection side and a second side opposite the fluid collection side, and a porous wick adjacent the second side of the heater element.
A further embodiment of the disclosure provides a method for vaporizing a fluid ejected by an ejection head so that substantially all of the fluid ejected by the ejection head is vaporized. The method includes providing a mouthpiece for sucking in vapors generated by a foraminous vaporizing heater, disposing a porous wick adjacent to the vaporizing heater in the mouthpiece, wherein the wick is disposed on a side of the vaporizing heater opposite a side of the vaporizing heater that faces the ejection head so that the wick is heated by the vaporizing heater and collects and vaporizes any fluid passing through the foraminous vaporizing heater.
In some embodiments, the mouthpiece has a cavity therein for the heater assembly, a vapor outlet port disposed adjacent to the vapor outlet end of the heater assembly and one or more air intake ports disposed adjacent to the vapor inlet end of the heater assembly wherein ambient air is drawn through the vaporizing heater and the wick.
In another embodiment, a support housing is attached to the mouthpiece. The support housing includes a fluid reservoir, an ejection head, and logic control for metering the amount of fluid jetted to the vaporizing heater and for activating the vaporizing heater.
In yet another embodiment, there is a provided a vaporizing device housing for containing the support housing, power circuitry, and a power source for the vaporizing device.
In some embodiments, the wick is a resilient, porous material selected from ceramic, sintered metal, metal/ceramic composite materials, wire mesh, steel wool, fiberglass, and the like. The wick is selected to provide a predetermined negative pressure for the vaporizing device.
In some embodiments, the porous wick is disposed between the heater element and an insulator for heater terminals of the heater element.
In some embodiments, the fluid container is a removable fluid container and ejection head assembly.
In some embodiments, the housing body of the vaporizing device includes a power switch, a vapor activation button, and a USB port.
In some embodiments, an amount of negative pressure adjacent the ejection head is reduced by providing air intake ports in the mouthpiece to provide air flow between the ejection head and the vaporizing heater.
Other features and advantages of the inventive may be evident by reference to the following detailed description, drawings and claims wherein:
The disclosure is directed to a vaporizing device 10 as shown in
The mouthpiece 12, as well as the body 16 of the vaporizing device 10 may be made from a wide variety of materials including plastics, metals, glass, ceramic and the like provided the materials are compatible with the fluids to be ejected and vaporized by the device 10. A particularly suitable material may be selected from polyvinyl chloride, high density polyethylene, polycarbonate, stainless steel, surgical steel, nickel-plated steel, and the like. All parts, including the mouthpiece 12, and body 16 that come in contact with fluids and vapors may be made of plastic. The vapor exit conduit 14 may be made of metal such as stainless steel or other material that is resistant to heat and vapors generated by the device.
A cross sectional view of the device 10 is shown in
An important component of the vaporizing device is the removable vapor ejection assembly 18 shown in more detail in
An exploded view of portions of the removable vapor ejection assembly 18 is shown in more detail in
As shown in
The wick 56 is a porous material, described in more detail below, that provides an important function in the operation of the vaporizing device 10. The wick 56 in combination with air intake ports 54 in the mouthpiece 12 enable operation of the vaporizing device 10 without imposing a negative pressure adjacent the fluid discharge side of the ejection head 34. Avoiding a negative pressure adjacent the ejection head 34 is important in order to prevent excessive liquid from discharging from the ejection head 34. Thus the correct placement of the porous wick 56 in the heater assembly 36 is important and must be down stream of the air intake ports 54. If the porous wick 56 were positioned in contact with the ejection head 34, liquid would be caused to drool out of the ejection head 34 and the air intake ports 54 would be ineffective for maintaining atmospheric pressure adjacent the discharge side of ejection head 34. Accordingly, the flow of fluid from ejection head 34 is suitably across an air gap between the ejection head 34 and the heater 48 wherein ambient air is introduced to maintain atmospheric pressure adjacent the discharge side of the ejection head 34 regardless of the negative pressure imposed by a user on the vapor exit conduit 14 through the porous wick 56 and vaporizing heater 48.
Also by placing the vaporizing heater 48 between the ejection head 34 and the porous wick 56, fluid ejected from the ejection head 34 that does not impact on the surface of the vaporizing heater 48 will be disposed on the surface of the porous wick 56 adjacent the heater 48. Since the porous wick 56 is in contact with the vaporizing heater 48, the fluid on the surface of the wick 56 will also be vaporized so that no liquid is discharged through the vapor exit conduit 14. All of the pressure drop imposed by the vapor exit conduit 14 is thus taken through the porous wick 56 without imposing a negative pressure adjacent the discharge side of the ejection head 34. In one embodiment, the pressure drop through the wick may range from about 10 to about 100 cm water column.
The wick 56 may be made of a variety of resilient materials including ceramic, sintered metal, composite ceramic and metal materials, wire mesh, steel wool, fiberglass, and the like. As shown in
As air is drawn through the vapor exit conduit 14, air is also drawn in through air intake ports 54 that are upstream of the vaporizing heater 48 so that the jetted fluid is focused onto the vaporizing heater 48 without disrupting the jetted fluid flow. All fluid from the ejection head 34 is jetted onto vaporizing heater 48 and/or wick 56 due to the direction of air flow through the vaporizing heater 48 and wick 56 indicated by arrows 64 and 66 (
Accordingly, the foregoing configuration of vaporizing heater 48, wick 56 and air intake ports 54 work in conjunction with one another to improve the efficiency of vaporization of fluid from the ejection head 34 and reduce or eliminate any drooling of liquid from the ejection head 34.
While particular embodiments have been described, alternatives, modifications, variations, improvements, and substantial equivalents that are or can be presently unforeseen can arise to applicants or others skilled in the art. Accordingly, the appended claims as filed and as they can be amended are intended to embrace all such alternatives, modifications variations, improvements, and substantial equivalents.
This application claims priority to provisional application Ser. No. 62/281,804, filed Jan. 22, 2016.
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