U.S. patent application number 15/418435 was filed with the patent office on 2017-08-03 for vapor delivery systems and methods.
The applicant listed for this patent is Stratos Product Development LLC. Invention is credited to Dainia Edwards, Christopher B. Harrison, Eric W. Healy, Joseph N. Kennelly Ullman, Gregory A. Kirkos, Alga Lloyd Nothern, III, Steven A. Rodriguez.
Application Number | 20170215478 15/418435 |
Document ID | / |
Family ID | 59386079 |
Filed Date | 2017-08-03 |
United States Patent
Application |
20170215478 |
Kind Code |
A1 |
Harrison; Christopher B. ;
et al. |
August 3, 2017 |
VAPOR DELIVERY SYSTEMS AND METHODS
Abstract
There is provided an electronically controlled, breath actuated
vaporization device for generating vaporized material for
inhalation by a user. The vaporization device includes a
vaporization chamber for accommodating material to be vaporized and
a mesh heater or other heater supported upstream of the
vaporization chamber which is operable to heat air that passes
through the mesh heater or other heater during an inhalation event.
A closed loop control scheme may be employed to control heat
generated by the heater to maintain a temperature of the air
delivered to the vaporization chamber at or within a predetermined
tolerance of a desired vaporization temperature for at least a
majority of a duration of the inhalation event.
Inventors: |
Harrison; Christopher B.;
(Vashon, WA) ; Rodriguez; Steven A.; (Seattle,
WA) ; Kirkos; Gregory A.; (Seattle, WA) ;
Nothern, III; Alga Lloyd; (Seattle, WA) ; Edwards;
Dainia; (Issaquah, WA) ; Kennelly Ullman; Joseph
N.; (Seattle, WA) ; Healy; Eric W.; (Seattle,
WA) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Stratos Product Development LLC |
Seattle |
WA |
US |
|
|
Family ID: |
59386079 |
Appl. No.: |
15/418435 |
Filed: |
January 27, 2017 |
Related U.S. Patent Documents
|
|
|
|
|
|
Application
Number |
Filing Date |
Patent Number |
|
|
62288314 |
Jan 28, 2016 |
|
|
|
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
A24F 7/02 20130101; A24F
40/40 20200101; A24F 47/008 20130101 |
International
Class: |
A24F 47/00 20060101
A24F047/00; A24F 7/02 20060101 A24F007/02 |
Claims
1. A vaporization device for delivering vaporized material for
inhalation by a user, the vaporization device comprising: an air
intake through which air enters the vaporization device during an
inhalation event; an outlet through which vapor is withdrawn from
the vaporization device during the inhalation event; a vaporization
chamber for accommodating material to be vaporized; a mesh heater
supported upstream of the vaporization chamber and operable to heat
air which passes through the mesh heater during the inhalation
event as the air moves from the air intake toward the outlet; a
temperature sensor positioned downstream of the mesh heater and
operable to sense a temperature of the air downstream of the mesh
heater; and a control system, the control system operatively
coupled to the temperature sensor and the mesh heater to provide a
closed loop control scheme for controlling heat generated by the
mesh heater to maintain a temperature of the air delivered to the
vaporization chamber at or within a predetermined tolerance of a
desired vaporization temperature for at least a majority of a
duration of the inhalation event.
2. The vaporization device of claim 1 wherein the mesh heater
comprises a mesh of a first material and a frame of a second
material, the mesh being fixed to the frame and supported by the
frame within the vaporization device.
3. The vaporization device of claim 2 wherein the first material of
the mesh is a stainless steel material and the second material of
the frame is a ceramic material.
4. The vaporization device of claim 2 wherein the frame is a
portion of a frame assembly that further comprises opposing bus
bars integrally formed therewith, and wherein opposing ends of the
mesh and heater leads are bonded to the opposing bus bars for
supplying current through the mesh in accordance with the closed
loop control scheme.
5. The vaporization device of claim 1, further comprising: a nozzle
block for supporting the mesh heater upstream of the vaporization
chamber, the nozzle block including a nozzle passage shaped to
funnel the air passing through the mesh heater toward a central
location.
6. The vaporization device of claim 5 wherein a temperature sensing
end of the temperature sensor is positioned at the central
location.
7. The vaporization device of claim 5 wherein the mesh heater is
held offset from the nozzle block via one or more bosses such that,
apart from the one or more bosses, a space is maintained between
the mesh heater and the nozzle block to reduce conductive heat
transfer from the mesh heater to the nozzle block during
operation.
8. The vaporization device of claim 7, further comprising a housing
that accommodates the mesh heater and the nozzle block, and wherein
the nozzle block is held offset from the housing via one or more
other bosses such that, apart from the one or more other bosses, a
space is maintained between the nozzle block and the housing to
reduce conductive heat transfer between the nozzle block and the
housing during operation.
9. The vaporization device of claim 1 wherein the vaporization
chamber is defined at least in part by a heat exchanger, the heat
exchanger including a plurality of vapor flow passages extending
between the vaporization chamber and the outlet.
10. The vaporization device of claim 9 wherein the plurality of
vapor flow passages in the heat exchanger comprise opposing
passages offset from a central plane of the vaporization device, a
central portion of the heat exchanger providing an obstruction
around which the vapor must flow to reach the outlet, and whereby
heat is transferred from the vapor to the heat exchanger as the
vapor moves toward the outlet.
11. The vaporization device of claim 10 wherein the heat exchanger
is configured such that a portion of the heat transferred to the
heat exchanger from the vapor is conducted upstream to a location
adjacent the vaporization chamber to assist in heating the material
to be vaporized via conduction.
12. The vaporization device of claim 1 wherein the control system
is configured to initiate a soft start in response to an initiation
signal and to transition to the closed loop control scheme upon
detection of a thermal response that exceeds a threshold level or
threshold rate of temperature change arising from inhalation by a
user.
13. The vaporization device of claim 12, further comprising a
trigger device accessible to the user to enable the user to
generate the initiation signal.
14. The vaporization device of claim 12, further comprising a
pressure sensor communicatively coupled to the control system to
generate the initiation signal upon sensing a change in pressure
associated with inhalation by the user.
15. The vaporization device of claim 12 wherein the control system
is configured to disable the mesh heater upon detection of a
divergence of a measured air temperature associated with a
delivered heater power from an expected air temperature, the
divergence arising from a lack of air flow through the vaporization
device resulting from cessation of the inhalation event.
16. The vaporization device of claim 1 wherein the vaporization
device comprises a vaporization head removably coupled to a base
assembly, the base assembly including the mesh heater, the
temperature sensor, the control system and a power source
accommodated within a housing.
17. The vaporization device of claim 16 wherein the vaporization
head includes a heat exchanger received within a removable
mouthpiece, the vaporization chamber defined at least in part by
the heat exchanger.
18. The vaporization device of claim 16 wherein the vaporization
head is removably coupled to the base assembly via a magnetic
coupling.
19. The vaporization device of claim 1, further comprising a vapor
concentration detection arrangement operatively coupled to the
control system to provide signals indicative of a concentration of
vapor in an air-vapor mixture generated in the vaporization chamber
from which to modify operation of the mesh heater.
20. The vaporization device of claim 19 wherein the vapor
concentration detection arrangement comprises one or more light
sources and one or more sensors configured to detect vapor
concentration via an obscuration technique.
21. The vaporization device of claim 19 wherein the vapor
concentration detection arrangement comprises one or more light
sources and one or more sensors configured to detect vapor
concentration via a light scattering technique.
22. A vapor delivery device, comprising: a vaporization chamber to
receive matter to be vaporized; a heater located upstream of the
vaporization chamber; a temperature sensor located downstream of
the heater; one or more processors; and at least one memory, the
memory including instructions that, upon execution by at least one
of the one or more processors, cause the heater to maintain a
temperature of air delivered to the vaporization chamber at or
within a predetermined tolerance of a desired vaporization
temperature for at least a majority of a duration of an inhalation
event using temperature information received from the temperature
sensor.
Description
BACKGROUND
[0001] Technical Field
[0002] This disclosure generally relates to vapor delivery systems
and methods and, more particularly, to vaporization devices
suitable for selectively delivering vaporized material (e.g., plant
material, including plant material extracts, concentrates, and
derivatives) for inhalation by a user, components thereof and
related methods.
[0003] Description of the Related Art
[0004] Vaporization devices suitable for selectively delivering
vaporized plant material for inhalation by a user are well known in
the art. Such devices, however, may suffer from a variety of
deficiencies and drawbacks, such as, for example, inefficient heat
management and delayed vapor delivery arising from prolonged device
warmup.
BRIEF SUMMARY
[0005] Embodiments described herein provide vaporization devices
suitable for selectively delivering vaporized plant material (or
other materials) in an efficient and reliable manner for inhalation
by a user. Embodiments include vaporization devices comprising a
closed loop temperature control technique to drive current from a
power source to a forced convection air heater to provide rapid,
on-demand vapor delivery. Embodiments may further include breath
detection functionality to assist in delivering the vaporized
material on-demand. Embodiments may be provided in multi-part form
factors including, for example, a vaporization head detachable from
a base assembly, which includes the system electronics. The
vaporization head includes a vaporization chamber for receiving the
material to be vaporized. The vaporization head may be configured
to dissipate heat and sufficiently cool the vapor stream for safe
and comfortable inhalation by the user. Advantageously, the
vaporization devices may be configured to enable a user to safely
inhale vaporized plant material on-demand without significant delay
despite fluctuations in inhalation strength, inhalation duration,
ambient environmental conditions, and/or plant material
characteristics (e.g., size, moisture content), thereby enhancing
user experience.
BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS
[0006] FIG. 1 is an isometric view of a vaporization device,
according to one example embodiment, from a top perspective.
[0007] FIG. 2 is an isometric view of the vaporization device of
FIG. 1 from a bottom perspective.
[0008] FIG. 3 is a side elevational view of the vaporization device
of FIG. 1.
[0009] FIG. 4 is an isometric view of the vaporization device of
FIG. 1 with a vaporization head detached from a base assembly
thereof.
[0010] FIG. 5 is a skewed isometric exploded view of the
vaporization device of FIG. 1 from a top perspective.
[0011] FIG. 6 is a skewed isometric exploded view of the
vaporization device of FIG. 1, from a bottom perspective.
[0012] FIG. 7 is an isometric view of a vaporization device,
according to another example embodiment, from a top
perspective.
[0013] FIG. 8 is an isometric view of the vaporization device of
FIG. 7 with external components shown transparent to reveal
underlying features and components thereof.
[0014] FIG. 9 is a skewed isometric view of the vaporization device
of FIG. 7 with external components shown partially cut away to
reveal underlying features and components thereof.
[0015] FIG. 10 is a skewed isometric view of the vaporization
device of FIG. 7 with a vaporization head detached from a base
assembly thereof, and with a removable material screen removed from
a vaporization chamber provided by the vaporization head.
[0016] FIG. 11 is a partial cross-sectional view of a front end of
the vaporization device of FIG. 7 showing internal features and
components of the device.
[0017] FIG. 12 is a top plan view of the internal components of the
vaporization device of FIG. 7 showing a path and relative
temperature profile of the air and air-vapor mixture moving through
the device during an inhalation event.
[0018] FIG. 13 provides diagrams of a mesh heater, according to one
embodiment, from front and side perspectives.
[0019] FIG. 14 shows additional details of an example embodiment of
a nozzle block for supporting a mesh heater within the vaporization
device.
[0020] FIG. 15 provides a schematic diagram of a closed loop air
temperature control system, according to one example
embodiment.
[0021] FIG. 16 provides an example plot of air temperature and
corresponding heater output percentage over an approximately 30
second inhalation event in accordance with a closed loop air
temperature control scheme.
[0022] FIG. 17 provides a system block diagram of a vaporization
device, according to one example embodiment.
[0023] FIG. 18 provides an electronics block diagram of a
vaporization device, according to one example embodiment.
[0024] FIG. 19 illustrates a vapor concentration measurement
device, according to one example embodiment.
[0025] FIG. 20 provides a representative plot of obscuration
measurements over three vapor production cycles.
[0026] FIG. 21 provides schematic diagrams of two example light
scattering/detection arrangements.
[0027] FIG. 22 provides schematic diagrams of two example light
scattering arrangements comprising a multi-angle system (upper
right image) and a multi-wavelength system (lower right image).
DETAILED DESCRIPTION
[0028] In the following description, certain specific details are
set forth in order to provide a thorough understanding of various
disclosed embodiments. However, one of ordinary skill in the
relevant art will recognize that embodiments may be practiced
without one or more of these specific details. In other instances,
well-known structures and devices associated with vapor delivery
devices, systems, components or related methods may not be shown or
described in detail to avoid unnecessarily obscuring descriptions
of the embodiments.
[0029] Unless the context requires otherwise, throughout the
specification and claims which follow, the word "comprise" and
variations thereof, such as, "comprises" and "comprising" are to be
construed in an open, inclusive sense, that is as "including, but
not limited to."
[0030] Reference throughout this specification to "one embodiment"
or "an embodiment" means that a particular feature, structure or
characteristic described in connection with the embodiment is
included in at least one embodiment. Thus, the appearances of the
phrases "in one embodiment" or "in an embodiment" in various places
throughout this specification are not necessarily all referring to
the same embodiment. Furthermore, the particular features,
structures, or characteristics may be combined in any suitable
manner in one or more embodiments.
[0031] As used in this specification and the appended claims, the
singular forms "a," "an," and "the" include plural referents unless
the content clearly dictates otherwise. It should also be noted
that the term "or" is generally employed in its sense including
"and/or" unless the content clearly dictates otherwise.
[0032] Embodiments described herein provide vaporization devices
suitable for selectively delivering vaporized plant material (or
other material) in an efficient and reliable manner for inhalation
by a user. Embodiments include vaporization devices that utilize a
closed loop temperature control technique to drive current from a
power source to a forced convection air heater to provide rapid,
on-demand vapor delivery. Embodiments may further include breath
detection functionality to assist in delivering the vaporized plant
material on-demand. Embodiments may be provided in multi-part form
factors including, for example, a vaporization head detachable from
a base assembly, which includes the system electronics. The
vaporization head includes a vaporization chamber for receiving the
material to be vaporized. The vaporization head may be configured
to dissipate heat and sufficiently cool the vapor stream for safe
and comfortable inhalation by the user. Advantageously, the
vaporization devices may be configured to enable a user to safely
inhale vaporized plant material on-demand without significant delay
despite fluctuations in inhalation strength, inhalation duration,
ambient environmental conditions, and/or plant material
characteristics (e.g., size, moisture content), thereby enhancing
user experience.
[0033] Although the vaporization devices and methods described
herein are shown and described often in the context of handheld,
electronically controlled, breath actuated vaporizer devices for
delivering vaporized plant material to a user, it will be
appreciated by those of ordinary skill in the relevant art that
features and aspects of such devices may be applied to other
devices and for other purposes, including, for example, benchtop
vaporization devices or systems for delivering vaporized material
for recreational, medical or other purposes.
[0034] FIGS. 1 through 6 show one example embodiment of a handheld,
electronically controlled, battery driven, breath actuated vapor
delivery unit in the form of a vaporizer device 10. The vaporizer
device 10 includes a base assembly 12, which includes the system
electronics contained in a housing 13a, 13b, and a vaporizer head
14 that is removably coupleable to the base assembly 12 for
vaporizing material (e.g., plant material, including plant material
extracts, concentrates and derivatives) loaded in the vaporizer
head 14 for inhalation by a user. The vaporization head 14 may be
removably coupled to the base assembly 12 via a magnetic coupling
arrangement 15 or other coupling arrangement, such as, detents,
snaps, clips, latches, or other fasteners.
[0035] The vaporizer device 10 includes an air intake 20 (e.g.,
plurality of intake apertures), through which air enters the
vaporization device 10 during an inhalation event, and an outlet
22, through which vapor is withdrawn from the vaporization device
10 by the user. The vaporization device 10 further includes a
vaporization chamber 24 for accommodating the material to be
vaporized. According to the example embodiment shown in FIGS. 1
through 6, the vaporization head 14 may include a heat exchanger 26
and a removable mouthpiece 28 detachably coupled to the heat
exchanger 26. The vaporization chamber 24 is defined at least in
part by the heat exchanger 26 and is accessible to a user by
removing the mouthpiece 28 from the heat exchanger 26. In this
manner, a user may conveniently remove or disengage the mouthpiece
28 from the heat exchanger 26 to load the vaporization device 10
with material to be vaporized as desired. The mouthpiece 28 may be
removably coupled to the heat exchanger 26 via one or more detent
mechanisms 29 or other coupling arrangements, such as, snaps,
clips, latches, magnets or other fasteners. In other instances, the
vaporization chamber 24 may be selectively accessible to a user
without removing the mouthpiece 28. For example, the mouthpiece 28
may slide relative to the heat exchanger 26 to reveal the
vaporization chamber 24 while remaining coupled to the heat
exchanger 26. In other instances, an access panel or cover may
provide access to the vaporization chamber 24.
[0036] The heat exchanger 26 includes one or more vapor flow
passages 27 extending from the vaporization chamber 24 toward the
outlet 22. For instance, the example embodiment of FIGS. 1 through
6 includes a heat exchanger 26 having opposing passages 27 offset
from a central plane of the vaporization device 10. The heat
exchanger 26 further includes a central portion that provides an
obstruction around which the vapor must flow to reach the outlet
22. As the generated vapor moves through the vapor flow passages
27, heat is transferred from the vapor to the heat exchanger 26 to
assist in cooling the vapor prior to inhalation by the user.
According to the example embodiment, the heat exchanger 26 is
configured such that a portion of the heat transferred to the heat
exchanger 26 from the vapor is conducted upstream to a location
adjacent the vaporization chamber 24 to assist in heating the
material to be vaporized via conduction.
[0037] The vaporization device 10 further includes a mesh heater 30
supported upstream of the vaporization chamber 24, which is
operable to heat air which passes through the mesh heater 30 during
each inhalation event as it moves from the air intake 20 toward the
outlet 22. The mesh heater 30 may comprise a wire mesh 32 of a
first material (e.g., stainless steel) and a frame 34 of a second
material (e.g., ceramic material). The wire mesh 32 is fixed to the
frame 34 and supported by the frame 34 within the vaporization
device 10. The frame 34 may be a portion of a frame assembly that
further comprises opposing bus bars (e.g., low resistance, copper
bus bars) integrally formed therewith. Opposing ends of the mesh 32
may be bonded (e.g., silver soldered) to the opposing bus bars,
along with heater leads (not shown) for supplying electric current
through the mesh 32 in accordance with the control system
functionality disclosed herein.
[0038] The vaporization device 10 may further comprise a nozzle
block 36 for supporting the mesh heater 30 upstream of the
vaporization chamber 24. The nozzle block 36 may include a nozzle
passage 38 that is shaped to funnel air passing through the mesh
heater 30 toward a central location (as illustrated best in the
example embodiment shown in FIG. 14). The vaporization device 10
may further include one or more temperature sensor(s) (e.g., one or
more thermocouple(s)) positioned downstream of the mesh heater 30
which are operable to sense a temperature of the air downstream of
the mesh heater 30 at the central location and/or other locations.
Temperature readings may be used to control various operational
aspects of the vaporization device 10 as described herein.
Temperature sensing locations may include immediately downstream of
the mesh heater 30 to sense a temperature of the heated air stream
generated by the mesh heater 30, within the vaporization chamber
24, immediately downstream of the vaporization chamber 24, at or
near the outlet 22, and at or near the air intake 20.
[0039] The vaporization device may further include a control system
50, comprising one or more printed circuit board assemblies 52, 54,
which is/are operatively coupled to the temperature sensor and the
mesh heater 30 to provide a closed loop control scheme for
controlling heat generated by the mesh heater 30 so as to maintain
a temperature of the air delivered to the vaporization chamber 24
at or within a predetermined tolerance of a desired vaporization
temperature for at least a majority of a duration of an inhalation
event. The control system 50 may further include a power source 56
(e.g., a low voltage, high current battery) and a charging circuit,
including a power connector 58, for enabling the power source 56 of
the vaporization device 10 to be recharged as needed.
[0040] The vaporization device 10 may further include a pressure
sensor 60 operatively coupled to the control system 50 to sense the
initiation of an inhalation event. The pressure sensor 60 may be
positioned upstream of the mesh heater 30 and configured to sense a
drop in pressure as a user begins to inhale on the device 10.
Advantageously, the pressure sensor 60 may be used to initiate a
soft start of the mesh heater 30 in accordance with aspects of the
control methodology described herein prior to employing the closed
loop control scheme. In other embodiments, the vaporization device
10 may further include a trigger (e.g., depressible button) to
initiate the soft start of the mesh heater 30. In still other
embodiments, the pressure sensor 60 may be used to measure pressure
periodically or constantly throughout the inhalation event, and the
mesh heater 30 may be controlled based at least in part on such
pressure measurements.
[0041] FIGS. 7 through 11 show a vaporization device having the
same or similar features to the example embodiment of the
vaporization device 10 of FIGS. 1 through 6. Select features of the
vaporization device are labeled in the figures for additional
clarity.
[0042] FIG. 12 illustrates the air and air-vapor mixture moving
through a front end of the vaporization device during an inhalation
event. As can be appreciated from a review of FIG. 12, relatively
cool ambient air is drawn into the device during inhalation through
an air intake, as represented by the blue arrow. Upon passing
through a mesh heater, the air is rapidly heated to a desired
vaporization temperature (e.g., approximately 225.degree. C. for
vaporizing certain types of plant matter), as represented by the
red arrow. Then, the heated air interacts with the material to be
vaporized in the vaporization chamber to generate an air-vapor
mixture that is discharged from the vaporization chamber at a lower
exit temperature, as represented by the arrow transitioning from
red to yellow. Next, air-vapor mixture moves through vapor flow
passages of a heat exchanger whereby heat is transferred from the
air-vapor mixture to the heat exchanger to cool the air-vapor
mixture to a comfortable temperature before being discharged
through the outlet of the vaporization head for inhalation, as
represented by the arrows transitioning from yellow to blue.
Advantageously, some of the heat from the air-vapor mixture may be
reclaimed by the heat exchanger for conductive heating of the
material to be vaporized, as represented by the yellow arrows
outlined in broken lines.
[0043] FIG. 13 provides a schematic representation of a mesh heater
according to aspects of the vaporizer devices described herein. The
mesh heater is a compact, high power density, high efficiency
forced-convection air heater for flowing air which is configured to
provide a rapid rate of heating. The mesh heater is depicted in
FIG. 13 with a wire mesh resistive element 1 held in housing 2,
which is electrically insulating or has an insulating layer. Bus
bars 3 provide connections at opposing ends of the wire mesh
resistive element 1, and are connected to wire leads (not shown)
which provide electrical power to the heating element (i.e., wire
mesh resistive element 1). An air opening 4 is provided adjacent
the mesh, and converges to a nozzle/mixer 5, wherein a temperature
measurement element 6 is provided. The mesh heater rapidly heats
air through forced convection. Electrical current is passed through
the mesh resistive element 1, which then heats to a high surface
temperature. Air flowing through the mesh heater is heated by the
wire mesh resistive element 1. The mesh heater is of low electrical
resistance, and the convection is very efficient, two factors which
combine to give the heater a fast thermal time constant and effect
a rapid heating rate of the air. Heated air flows into the
nozzle/mixer 5 and heats the temperature measurement element 6,
which can be used to effect closed-loop temperature control. The
bus bars 3 are connected to the mesh 1 with a low resistance
connection. The housing 2 is mechanically robust, which protects
the delicate wire mesh resistive element 1 from external physical
loads. The housing 2 also provides thermal management of the wire
leads (not shown). The material of the mesh 1 may have a positive
temperature coefficient of resistance, which helps to self-limit
the temperature of the heater during operation.
[0044] Advantageously, the mesh heater provides a particularly
compact and efficient form factor for transferring a large amount
of heat into a flow of air, especially when considering power
consumption in relation to heat transferred into the moving air
stream. The mesh heater may provide a particularly rapid heating
rate of the air flow (e.g., up to and exceeding 100.degree. C.,
150.degree. C. or 200.degree. C. per second) with the use of a
low-mass, low impedance mesh heating element 1. The heating element
may be a single piece of fine wire mesh 1. The heating element may
be designed to be powered with a low voltage, high current battery.
The heating element may provide particularly efficient heating as
nearly all power consumed may be transferred to the moving air
stream via convection with minimal losses. The heating element may
provide a high surface area-to-volume ratio thereby providing a
high thermal power density. The mesh heater may comprise a
mechanically robust form factor having an integrated housing 2. The
temperature measurement element 6 may be integrated with the
housing 2 and supported at a central location. The housing 2 may
provide a nozzle or funnel which forces the air flowing through the
mesh resistive element 1 to mix so that a single point temperature
measurement more accurately represents the average temperature of
the flowing air stream. The mesh resistive element 1 may comprise
stainless steel, which has the property of self-limiting the
electrical current through the mesh resistive element 1 since the
electrical resistance of the stainless steel mesh increases with
temperature as it heats up. This helps prevent the mesh resistive
element 1 from self-fusing or from other damage. The stainless
steel mesh resistive element 1 may provide a safer material with
regard to biocompatibility and inhalation when compared to Nichrome
(NiCr) and other common resistive heating element materials.
[0045] Although the example embodiment of the vaporizer device 10
shown in FIGS. 1 through 6 and other embodiments are described as
including a mesh heater, it is appreciated that in other
embodiments, other types of heaters and heating elements may be
used in conjunction with other aspects and features of the
vaporization devices, components and related methods disclosed
herein. For example, a heater element in the form of a coil,
pancake coil, wire screen, wire array or other heater element
device or arrangement may be provided in lieu of the wire mesh
32.
[0046] FIG. 14 shows different views of an example nozzle block
(similar to nozzle block 36 of FIGS. 5 and 6) to further illustrate
an example of a location of the temperature sensor and funneling
characteristics of the nozzle passage thereof, which may assist in
mixing the heated air stream to obtain a more accurate reading of
the average air temperature of the air stream passing through the
mesh heater (or other heater). In addition, FIG. 14 highlights
features of the example nozzle block which help manage heat
management within the device. As can be appreciated from a review
of FIG. 14, the mesh heater may be held offset from the nozzle
block via one or more bosses such that, apart from the one or more
bosses, a space is maintained between the mesh heater and the
nozzle block. This helps to reduce conductive heat transfer from
the mesh heater to the nozzle block during operation. Although the
bosses are shown as being integrally formed with the nozzle block,
it is appreciated that the bosses may be provided by the frame of
the mesh heater rather than the nozzle block. Alternatively, one or
more spacers or mounting members may be provided in lieu of bosses.
The nozzle block may also be held offset from the device housing
via one or more bosses such that, apart from the one or more other
bosses, a space is maintained between the nozzle block and the
housing. This helps to reduce conductive heat transfer between the
nozzle block and the housing during operation. Although the bosses
are shown as being integrally formed with the nozzle block, it is
appreciated that the bosses may be provided by the housing rather
than the nozzle block. Alternatively, one or more spacers or
mounting members may be provided in lieu of bosses.
[0047] FIG. 15 provides a schematic of a closed loop air
temperature control scheme that may be employed with embodiments of
the vaporizer devices described herein. The closed loop air
temperature control scheme may be used to quickly and accurately
heat air to a given temperature set point over a wide range of flow
rates, ambient conditions, and battery states in order to vaporize
target constituents of the material to be vaporized and inhaled.
The mesh heater (1), expressed schematically in FIG. 15 as a
resistor, may comprise a fine stainless steel mesh through which
air passes when a user inhales via a mouthpiece. Air temperature is
measured with a thermocouple (2) (or other temperature sensor)
placed in the air path, downstream of the heater (1). The
thermocouple signal is conditioned and amplified by an amplifier
(5) for measurement by an analog-to-digital converter (ADC) located
within a microcontroller (MCU) (6). When the user activates the
heater (1) (such as by inhaling on the mouthpiece), a software PID
loop (or other control loop feedback mechanism) in the MCU (6)
adjusts the output of the heater (1) based on feedback from the
signal of the thermocouple (2). Generally, if the thermocouple
measurement is less than the desired air temperature, the heater
output is increased. If the thermocouple measurement is greater
than the desired air temperature, the heater output is decreased.
The heater output will be adjusted throughout a use cycle in order
to maintain an output temperature that is equal to or within an
acceptable tolerance (e.g., .+-.5.degree. C., .+-.2.degree. C.) of
a desired set point or vaporization temperature. One side of the
heater (1) is connected to a power source (3) of the device, and
the other side is connected to a power MOSFET (4). When the gate of
the MOSFET (4) is driven high by the MCU (6), current passes
through the heater (1) and the MOSFET drain/source. When the gate
of the MOSFET (4) is driven low, the heater (1) is turned off and
no current flows. The on/off duty cycle may be modulated between
0-100% based on the feedback from the thermocouple (2). Pulse width
modulation (PWM) may be employed in the control scheme at a
frequency of 100 Hz, or at other frequencies. FIG. 16 provides a
representative graph of the temperature control scheme employed
over about a 30 second inhalation event.
[0048] The closed loop air temperature control scheme provides
enhanced temperature control to provide an improved user experience
as compared to other vaporizer devices which may set a heater
element at a fixed output without feedback from a temperature
sensor, which would result in inaccurate temperature control
outside of narrow default operating conditions, such as flow rate,
ambient temperature, and battery voltage. Measuring the temperature
of the heated airstream directly, rather than the heater element,
provides enhanced control of the user experience over a wider range
of dynamic operating conditions (e.g., flow rate, ambient
temperature, and battery voltage). Advantageously, monitoring the
air temperature with a fine-wire thermocouple minimizes the thermal
mass of the sensor, and thus response time. This allows increased
accuracy of heater adjustment that may self-correct for different
inhalation rates, ambient temperatures, and/or battery voltages,
even if these parameters are changing significantly within a
single-use.
[0049] The closed-loop air temperature control scheme is designed
for the purpose of vaporizing target constituents on-demand in a
target material (e.g., plant material, including plant material
extracts, concentrates, and derivatives) for inhalation, and may be
configured in conjunction with the mesh heater to provide up to and
exceeding 100W to provide a fast response while heating air
200.degree. C. or more above ambient over a wide range of flow
rates (e.g., up to 10 liters per minute or more). An efficient
heater design will have near zero conducted heat loss to its
surrounding environment, such that all power provided to the heater
will be convectively transferred to the flowing air. As the design
approaches this ideal, it is imperative that the heater only be
activated when air is flowing in order to avoid heating the system
without an accompanying heat loss path.
[0050] The mesh heater is controlled via closed-loop control, with
feedback coming from a thermocouple in the air path downstream from
the heater. Without air moving through the heater, the air around
the temperature sensor may heat slightly, but not nearly enough to
approach the desired set point at the temperature sensor downstream
from the heater. Accordingly, the closed loop control would quickly
increase the heater output to 100% without any forced convection
air heat transfer, resulting in extremely high temperatures at the
heater element. This has the effect of shortening heater and
battery life, and, eventually, causing uncomfortable or, possibly,
dangerous touch temperatures at the surface of the device.
Accordingly, in order to mitigate this risk, a method for turning
on the heater at a low level momentarily in order to verify
expected thermal response from the air, and thus air velocity
beyond a minimum threshold, has been developed. This method assures
that the temperature control of the heater is only activated during
a valid breath.
[0051] As previously described, the mesh heater (1), expressed
schematically as a resistor, may comprise a fine mesh through which
air passes when a user inhales via a mouthpiece. Air temperature is
measured with a thermocouple (2) placed in the air path, downstream
of the mesh heater (1). The thermocouple signal is conditioned and
amplified by an amplifier (5) for measurement by an
analog-to-digital converter (ADC) located within the MCU (6). A
pressure sensor (7) may be included upstream of the heater for the
purpose of detecting air flow. When air flow above a minimal
threshold is detected, a heater soft start may be initiated. The
heater soft start is accomplished by enabling the heater at a low
duty cycle (e.g., 5% or less, 2% or less) and monitoring the
temperature sensor output for a rapid thermal response. In the
absence of adequate airflow, the reported temperature will
increase, but only slowly. With airflow, the temperature increases
much more rapidly. By monitoring the rate of temperature change,
dT/dt, the heater feedback control loop is initiated only when
dT/dt exceeds a software configurable threshold. If a heater soft
start exceeds a software configurable timeout period, the heater is
completely disabled and will not start again until a new breath is
detected with the pressure sensor (7) or other detection means.
[0052] Once initiated, the feedback control loop in the MCU (6)
adjusts the heater output based on feedback from the temperature
sensor signal. Generally, if the temperature sensor measurement is
less than the desired air temperature, the heater output is
increased. If the temperature sensor measurement is greater than
the desired air temperature, the heater output is decreased. The
heater output will be adjusted throughout a use cycle in order to
maintain an output temperature that is equal to or within an
acceptable tolerance of the desired set point or vaporization
temperature.
[0053] Advantageously, the soft start and associated control scheme
enables on-demand use of the vaporizer device without preheating,
which would otherwise require a more powerful heater and additional
safeguards to prevent false triggering, and which may scorch the
material or otherwise degrade the quality of the vapor and
subsequent user experience. The soft start function also allows
detection of adequate air flow prior to enabling closed-loop
control of the heater to its set point temperature. This function
is implemented without requiring any additional components beyond
what is needed for typical closed-loop control. Although the soft
start is described as being triggered by breath detection via a
pressure sensor (7), it is appreciated that in other embodiments a
user accessible trigger or other control may be provided in
addition to or in lieu of the pressure sensor (7) for triggering
the soft start.
[0054] The control system may also be configured to disable the
mesh heater and stop the closed loop feedback control scheme upon
detection of a divergence of a measured air temperature associated
with a delivered heater power from an expected air temperature, the
divergence arising from a lack of air flow through the vaporization
device (i.e., cessation of the inhalation event). For example, the
mesh heater may be operated at a given level (e.g., 40%.+-.2%) to
maintain a desired vaporization temperature (e.g., 200.degree.
C..+-.5.degree. C.). Then, upon cessation of the inhalation event,
the sensed temperature may drop significantly despite maintaining
the mesh heater at the same power level given the lack of moving
air that would otherwise transfer heat generated by the mesh heater
to the location of the temperature sensor. This divergence thus
signals that air flow has ceased and that the closed loop control
scheme should be disabled until another inhalation event
occurs.
[0055] FIG. 17 provides a system block diagram of a vaporization
device, according to one embodiment, and FIG. 18 provides an
electronics block diagram of a vaporization device, according to
one example embodiment. Features and associated functionality of
the vaporization devices will be readily apparent to those of
ordinary skill in the relevant art upon review of the block
diagrams and in view of various aspects of the vaporization devices
described elsewhere herein. For example, FIG. 17 schematically
depicts a control system comprising one or more microprocessors
that are communicatively coupled to a power supply (e.g., battery);
a charging port, such as may provide power charging functionality
for the power supply; one or more user controls (e.g., a trigger),
such as may be operated by a user to initiate the vaporization
process; one or more user feedback devices (e.g., LEDs, electronic
display), such as may be used to communicate information (e.g.,
power on/off state) to the user; a heater (e.g., wire mesh heater),
such as may be used to heat a flow of air moving through the
vaporization device during an inhalation event; a breath detection
sensor (e.g., pressure sensor), such as may be used to detect an
inhalation event and initiate a soft start of the heater; and a
temperature sensing device (e.g., thermocouple), such as may be
used to detect air temperature and provide a closed loop air
temperature control scheme in conjunction with the microprocessor
and the heater. The control system may also include one or more
memories, such as may store various information and/or
processor-executable instructions related to operations of the
control system. The control system may also include a wireless
communication module for receiving information from and/or
transmitting information to external devices or networks.
[0056] Although not depicted in the example embodiment of the
vaporization devices shown in FIGS. 1 through 6, it is appreciated
that in some embodiments, a vaporization device (including a
benchtop device) may be provided with one or more vapor
concentration measurement devices for modifying operational
parameters of the vaporization device based at least in part on
concentration measurement data obtained therefrom. In some
instances, for example, the vaporization device may be configured
to measure vapor concentration by obscuration. One example vapor
concentration measurement device is depicted in FIG. 19. As shown
in FIG. 19, the vapor concentration measurement device may include
an elongated measurement chamber through which a flow of vapor may
be passed through inlet and exhaust ports with a light source at
one end and an optical power meter or photodiode at the other end
to measure a change in power readings associated with a decrease in
the amount of light reaching the optical power meter or photodiode
as a result of light being obscured by vapor in the measurement
chamber. FIG. 20 provides a representative plot of obscuration
measurements over three vapor production cycles. As an example, the
first cycle is characterized by a power reading of about 3.95 mW
prior to vapor introduction and a power reading of about 3.51 mW
upon vapor introduction, thus resulting in a percentage of light
obscuration per foot of about 11.1% ((power before vapor-power
during vapor)/(power before vapor)*100). This information can then
be used, for example, to determine the concentration of vapor, and
ultimately to tailor the delivery of vapor at a desired
concentration for precise dosing purposes or to customize user
experience by targeting certain constituents. In addition,
concentration measurements may be used to determine when the
material to be vaporized has been consumed, such as, for example,
comparing measured concentration against expected concentration for
given operating parameters and/or by monitoring the rate of decline
in measured concentration. Additionally, vapor concentration
measured in real-time could allow for user feedback from the device
to indicate to the user that vapor is being produced. For example
haptic feedback may be provided from a vibration device mounted
inside the vaporizer, or visual feedback through an indicator
(e.g., LED, electronic display), based on such measurements. This
may address deficiencies of some known vaporizers in which it is
difficult for users to tell if they are receiving vapor.
[0057] In other embodiments, the vaporization device may be
configured to measure vapor concentration and/or detect combustion
particles via light scattering detection techniques as opposed to
measuring obscuration. Measuring light scatter has the
aforementioned advantages of detecting vapor concentration by
obscuration, but also has the added advantage that it can be used
to discriminate effluent from vapor. Detecting, and having the
ability to avoid, other gasses or particles in the vapor stream is
especially important in applications where end-users cannot
tolerate contaminants (e.g., asthmatic users), or more broadly,
when vapor purity is desired by the end-user. Furthermore, the
scatter detection approach may enable a very compact light
source/measurement area/detector to be constructed within a vapor
delivery device, such as, for example, a handheld vaporization
device. In some instances, light guides may be added to create a
form factor in which the light source (e.g., LED(s)) and photodiode
are co-planar for ease of packaging. FIG. 21 provides schematic
diagrams of two example light scattering arrangements wherein
photodiodes are arranged to detect light emanating from a light
source (e.g., LED) that is scattered by vapor moving through a
vaporization device to be inhaled by a user.
[0058] A multi-angle system or a multi-wavelength system may be
used to differentiate target vapor from other gasses or particulate
streams. Also, absolute magnitude of photodiode signal could be
used to differentiate particle size. Any of these methods may in
turn be used to differentiate desirable vapor particles from
undesirable particles for modifying or otherwise controlling user
experience. A vaporizing device may use this differentiation, for
example, to maximize vaporization without producing undesirable
particles. Differentiating based on wavelength or angle may not be
as sensitive to contamination or other outside influences as
differentiating based on the absolute magnitude of photodiode
signal. Furthermore, wavelength and angle discrimination give
particle differentiation independently of vapor concentration,
while differentiating based on the absolute magnitude of photodiode
signal would not. Since scatter intensity is dependent on incidence
angle, wavelength, and particle size, the scatter intensity as
measured by the photodiode for each LED, and the ratios of those
individual measurements, may be used to determine the type of
particles causing the scattering. FIG. 22 provides schematic
diagrams of two example light scattering arrangements comprising a
multi-angle system (upper right image) and a multi-wavelength
system (lower right image).
[0059] Aspects and features of the various embodiments described
above may also be combined to provide further embodiments. These
and other changes can be made to the embodiments in light of the
above-detailed description. In general, in the following claims,
the terms used should not be construed to limit the claims to the
specific embodiments disclosed in the specification and the claims,
but should be construed to include all possible embodiments along
with the full scope of equivalents to which such claims are
entitled.
CROSS-REFERENCE TO RELATED APPLICATIONS
[0060] This application claims the benefit of provisional
application No. 62/288,314, filed Jan. 28, 2016, which is
incorporated herein by reference in its entirety.
* * * * *