HEATER ELEMENT FOR A VAPORIZATION DEVICE
A heating element for a vaporizing device, a vaporizing device containing the heating element, and a method for vaporizing fluid ejected by an ejection head. The heating element includes a conductive material deposited onto an insulative substrate, a protective layer deposited onto the conductive layer, and a porous layer having a porosity of at least about 50% deposited onto the protective layer. The heating element has an effective surface area (ESA) for fluid vaporization that is greater than a planar surface area defined by dimensions of the heating element so that a fluid contact surface of the heating element is greater than the planar surface area of the heating element.
One of the applications of a fluidic ejection device is to jet a solution onto 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. A problem associated with such devices is efficient vaporization of the fluid. This document discloses improved heating elements and methods for improving the vaporization efficiency of heating elements for vaporization devices.
BACKGROUND AND SUMMARYWhen 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 has enough surface area to catch all fluid and fluid droplets that are being ejected onto the heating element. A typical metal foil heating element has a smooth surface with minimal liquid/heater interface which is due to a low surface roughness of the heating element surface. Accordingly, some of the fluid droplets impinging on the surface of the heating element will be scattered or fluid droplets will be ejected from the heating element if a significant layer of fluid already exists on the surface of the heating element when new droplets arrive. Thus, instead of only vapor being discharged from the vaporization device, liquid droplets may be entrained in the vapor and discharged from the vaporization device. In some applications, the discharge of liquid is not only undesirable, but may be detrimental to the user. Also, unvaporized fluid may build up inside the vaporization device and thus degrade the operation of the device.
In order to avoid the discharge of liquid droplets from a vaporization device, the stream of fluid ejected onto the surface of the heating element must be efficiently captured by the heating element, spread out over the surface of the heating element, and completely vaporized at approximately the same rate as the fluid arrives on the surface of the heating element in order to avoid liquid accumulation on the surface of the heating element.
In view of the foregoing, embodiments of the disclosure provide a heating element for a vaporizing device, a vaporizing device containing the heating element, and a method for vaporizing fluid ejected by an ejection head. The heating element includes a conductive material deposited onto an insulative substrate, a protective layer deposited onto the conductive layer, and a porous layer having a porosity of at least about 50% deposited onto the protective layer. The heating element has an effective surface area (ESA) for fluid vaporization that is greater than a planar surface area defined by dimensions of the heating element so that a fluid contact surface of the heating element is greater than the planar surface area of the heating element.
In one embodiment, the heating element has a rectangular shape. Accordingly, the effective surface area (ESA) of the heating element is defined by the equation ESA>L×W, wherein L is a length of the heating element and W is a width of the heating element that is exposed to a vaporizing fluid.
In another embodiment, the heating element has a circular shape. Accordingly, the effective surface area (ESA) of the heating element is defined by the equation ESA>π×R2 wherein R is a radius of the heating element that is exposed to a vaporizing fluid.
Another embodiment of the disclosure provides a vaporizing device that includes a housing body, a mouthpiece attached to the housing body, and a heating element disposed adjacent to the mouthpiece for vaporizing fluid ejected from an ejection head. The heating element has a conductive material deposited onto an insulative substrate, a protective layer deposited onto the conductive layer, and a porous layer having a porosity of at least about 50% deposited onto the protective layer.
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 vaporization device having an ejection head and a vaporizing heater element adjacent to the ejection head; ejecting fluid onto the heater element; activating the heating element during fluid ejection; and vaporizing substantially all of the fluid using the heating element. The heating element has a conductive material deposited on an insulative substrate, a protective layer deposited on the conductive layer, and a porous layer having a porosity of at least about 50% deposited onto the protective layer.
In some embodiments, the porous layer has a grit blasted surface texture that provides the effective surface area (ESA) thereof. In other embodiments, the porous layer is a grit blasted ceramic material.
In another embodiment, the porous layer is a laser etched ceramic layer.
In yet another embodiment, the porous layer is deposited as a coarse glass frit that is sintered onto a surface of the heating element.
In some embodiments, the porous layer has a thickness ranging from about 0.5 millimeters (mm) to about 3 mm. In other embodiments the porous layer has a thickness ranging from about 1 mm to about 2 mm.
In some embodiments, the insulative substrate, conductive layer and protective layer have a combined thickness ranging from about 4 millimeters (mm) to about 1 centimeter (cm)
In some embodiments, the porous layer has a porosity ranging from about 50% to about 95%.
In some embodiments, the conductive layer is a screen printed conductive layer deposited onto a ceramic substrate.
Other features and advantages of disclosed embodiments may be evident by reference to the following detailed description, drawings and claims wherein:
The disclosure is directed to a vaporization device 10 as shown in
The mouthpiece 12, as well as the body 16 of the vaporization 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 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.
As shown in
An inlet air flow control device may be included to provide backpressure control on the ejection head 22. The inlet air flow control device may include a damper slide 34 and air inlet holes 36 that allow air to be drawn into the conduit 14 adjacent the heating element 24 and ejection head 22 so that excessive negative pressure on the ejection head 22 can be avoided.
An important component of the vaporization device 10 is the heating element 24 as shown in
As set forth above, it is desirable to vaporize substantially all fluid ejected from the ejection head 22 so that only vapors are discharged through the conduit 14 of the mouthpiece 12. Accordingly, the heating element 24 desirably contains a fluid absorbing or capturing layer 44 that is formed on a protective layer 46. The protective layer 46 is positioned between the fluid absorbing or capturing layer 44 and the resistive or conductive metal material 42 and may be made of the same material as the ceramic base 40 or any other suitable, high temperature material that is substantially non-porous. Other suitable materials for the protective layer include, but are not limited to alumina, aluminum nitride, silica or silicon nitride.
The overall thickness T1 of the heating element may range from about four millimeters to about 1 centimeter. The thickness T2 of the fluid absorbing or capturing layer 44 may range from about 0.5 to about 3 millimeters in thickness, such as from about 1 to about 2 millimeters in thickness. The thicknesses of the resistive or conductive material 42 and protective layer 46 are not critical to the embodiments of the disclosure. In the case of an imbedded resistive or conductive material 42, a protective material layer 46 may not be necessary.
In one embodiment, as shown in
For a rectangular heating element having a width W, a length L and a thickness T1 as described above, the heating element 24 is further defined as having an effective surface area (ESA) for fluid vaporization that is defined by the equation ESA>L×W. For a circular heating element, the effective surface area (ESA) of the heating element is defined by the equation ESA>π×R2 wherein R is a radius of the heating element that is exposed to a vaporizing fluid. The heating element is not limited to a rectangular or circular shape as any shape including triangular, complex shapes, and the like may be used. Accordingly, the ESA of the heating element is greater than the nominal dimensions of the protective layer 46.
In another embodiment, as shown in
One method for making a heating element 24, according to an embodiment of the disclosure, is illustrated schematically in
In a next step of the process, as shown in
In the final step of the process,
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.
Claims
1. A heating element for a vaporization device comprising a conductive material deposited onto an insulative substrate, a protective layer deposited onto the conductive layer, and a porous layer having a porosity of at least about 50% deposited onto the protective layer wherein the heating element has an effective surface area (ESA) for fluid vaporization that is greater than a planar surface area defined by dimensions of the heating element so that a fluid contact surface of the heating element is greater than the planar surface area of the heating element.
2. The heating element of claim 1, wherein the heating element has a rectangular shape and has an effective surface are for fluid vaporization defined by the equation ESA>L×W, wherein L is a length of the heating element and W is a width of the heating element.
3. The heating element of claim 1, wherein the porous layer has a grit blasted surface texture providing the effective surface area (ESA) thereof.
4. The heating element of claim 1, wherein the porous layer has a thickness ranging from about 0.5 millimeters (mm) to about 3 mm.
5. The heating element of claim 1, wherein the insulative substrate, conductive layer and protective layer have a combined thickness ranging from about 4 millimeters (mm) to about 1 centimeter (cm).
6. The heating element of claim 1, wherein the porous layer has a porosity ranging from about 50% to about 95%.
7. The heating element of claim 1, wherein the conductive layer is a screen printed conductive layer deposited onto a ceramic substrate.
8. The heating element of claim 1, wherein the porous layer comprises a laser etched ceramic layer.
9. The heating element of claim 1, wherein the porous layer comprises a coarse grit deposited ceramic layer that is sintered.
10. A vaporization device comprising a housing body, a mouthpiece attached to the housing body, and a heating element disposed adjacent to the mouthpiece for vaporizing fluid ejected from an ejection head, wherein the heating element comprises a conductive material deposited onto an insulative substrate, a protective layer deposited onto the conductive layer, and a porous layer having a porosity of at least about 50% deposited onto the protective layer.
11. The vaporization device of claim 10, wherein the heating element has a rectangular shape and has an effective surface area (ESA) for fluid vaporization defined by the equation ESA>L×W, wherein L is a length of the heating element and W is a width of the heating element.
12. The vaporization device of claim 11, wherein the porous layer has a grit blasted surface texture providing the effective surface area (ESA) thereof.
13. The vaporization device of claim 10, wherein the porous layer has a thickness ranging from about 0.5 millimeters (mm) to about 3 mm.
14. The vaporization device of claim 10, wherein the insulative substrate, conductive layer and protective layer have a combined thickness ranging from about 4 millimeters (mm) to about 1 centimeter (cm).
15. The vaporization device of claim 10, wherein the porous layer has a porosity ranging from about 50% to about 95%.
16. 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, comprising providing a vaporization device having an ejection head and a vaporizing heater element adjacent to the ejection head;
- ejecting fluid onto the heater element;
- activating the heating element during fluid ejection; and
- vaporizing substantially all of the fluid using the heating element, wherein the heating element comprises a conductive material deposited on an insulative substrate, a protective layer deposited on the conductive layer, and a porous layer having a porosity of at least about 50% deposited onto the protective layer.
17. The method of claim 16, further comprising absorbing the fluid by the porous layer of the heating element, wherein the porosity of the heating element is defined by the equation ESA>L×W, wherein ESA is an effective surface area of the heating element, L is a length of the heating element and W is a width of the heating element having a rectangular shape and that is exposed to a vaporizing fluid.
18. The method of claim 16, wherein the porous layer is deposited as a coarse glass frit that is sintered onto the protective layer of the heating element.
19. The method of claim 16, wherein the porous layer is formed by grit blasting the protective layer or a ceramic layer deposited onto the protective layer of the heating element.
20. The method of claim 16, wherein the porous layer is formed by laser etching the protective layer or a ceramic layer deposited onto the protective layer of the heating element.
Type: Application
Filed: Dec 6, 2016
Publication Date: Jun 7, 2018
Inventor: Byron V. BELL (Lexington, KY)
Application Number: 15/369,961