Note: Descriptions are shown in the official language in which they were submitted.
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VAPORIZATION PIPE WITH FLAME FILTER
FIELD OF THE INVENTION
The present invention relates generally to smoking devices and vaporization
devices.
More particularly, the present invention relates to a pipe designed to provide
vaporization by
using heat from a flame.
BACKGROUND OF THE INVENTION
Tobacco or other herbs are typically smoked by burning and inhaling the
combustion
fumes and smoke. In recent years, interest has grown in the technique of
vaporization in which
the smoking material is carefully heated so that the desired flavor and
psychoactive
coinponents are liberated, and combustion is minimized.
Vaporization provides rnany benefits over smoking. When performed properly,
vaporization does not produce nearly as much toxic and carcinogenic pyrolytic
products as
smoking. Also, vaporization is smoother and more flavorful, and lacks a burned
taste that
many find disagreeable. Further, vaporization allows more efficient use of
smoking materials,
since desired flavor and psychoactive compounds are not destroyed by
combustion.
However, vaporization is difficult to perform, since vaporization only occurs
in a
relatively narrow temperature range. If the temperature is too low, desired
compounds are not
volatilized and nothing is inhaled; if the teinperature is too high,
combustion will occur, with
its attendant ill effects. For most smoking materials, vaporization is optimal
in a temperature
range of about 325-450 degrees Fahrenheit. The optimal temperature depends
upon the
compounds being vaporized.
Most vaporizers in use today are electrically powered. For vaporizing plant
materials
such as tobacco or marijuana, a temperature-controlled heat gun is often used.
Electrical
vaporization devices are inconvenient to use since they are not portable and
require electrical
line power. Typically, heat guns require several hundred watts of power. Also,
electrical
vaporization devices tend to be expensive.
Some vaporizer devices einploy a burning carbonaceous fuel element as a heat
source.
These devices are most well suited for use in cigarettes since the
carbonaceous fuel element
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burns for several minutes. However, a continuously burning fuel element is not
desired for
vaporizing some materials. Exemplary vaporizer devices in the prior art are
listed below:
US patent 4,219,032 describes a smoking device using a fuel element.
US patent 5,993,748 describes a vaporization device that is electrically
powered.
US patent 4,141,369 describes a vaporization device that is electrically
powered.
US patent 6,354,301 describes a vaporizer attachment for a pipe so that the
pipe can be
coupled to an electric heat gun.
US patent 4,303,083 describes a vaporizer that is electrically powered.
It would be an advance in the art of vaporization devices to provide a
vaporizer that
operates without electrical power, is inexpensive, is easily transportable, is
small, and is
simple to operate. Such a device could be widely used by tobacco smokers and
by users of
medicinal herbs such as marijuana or mullein. Such a device would also largely
avoid the
harmful effects of iiihaling toxic pyrolytic compounds found in smoke and
provide the other
benefits of vaporization.
SUMMARY
The present invention includes a vaporization device having a pipe with a bowl
for
holding smoking material (e.g. tobacco), and a heat resistant and porous
flaine filter for
receiving a flame, wherein the flame filter has a thiclaiess of at least 0.02
inches, and wherein
the flame filter is removably attachable to the pipe upstream from the bowl.
The flame filter
can also have thickness of at least 0.1 inch, or in the range of 0.125-0.75
inches. In one
embodiment, the flame filter is made of open cell ceramic foam, which can
comprise, silicon
carbide, silicon, cordierite or otller ceramics. The flaine filter causes
mixing between flame
exhaust and ambient air.
The flame filter can also be made of bonded granules (e.g. sintered metal or
ceramic
gra.nules), stacked discs (with each disc having at least one hole), a tangled
lump of metal
wire, or stacked screens, for example. Generally, the flaine filter material
should have a
thermal conductivity of at least 30 W/mK. The pipe can also have an airflow
shutter to
automatically regulate the amount of airflow into the flame filter, and
thereby regulate the
temperature. The device can also have a means for indicating temperature, such
as an
electronic temperature sensor with a display, or a bimetallic strip that moves
in response to
temperature.
In one usefiil embodiment, the flame filter comprises open cell silicon
carbide foam
made by chemical vapor deposition. The foam can have about 60-110 pores-per-
inch, for
example.
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According to one aspect of the present invention there is provided a
vaporization
device, comprising a) a pipe having a bowl for holding smoking material; b) a
heat resistant
and porous flame filter for receiving a flame, wherein the flame filter has a
thickness of at
least 0.02 inches, wherein the flame filter has tortured flow paths, and
wherein the flame
filter is attached to the pipe upstream from the bowl.
According to a further aspect of the present invention there is provided a
vaporization device, comprising a) a pipe having a bowl for holding smoking
material; b) a
heat resistant flame filter for receiving a flame, wherein the flame filter is
made of open-cell
ceramic foam, and wherein the flame filter is attached to the pipe upstream
from the bowl.
According to another aspect of the present invention there is provided a
vaporization device, comprising a) a pipe having a bowl for holding smoking
material; b) a
filter housing removably attachable to the pipe upstream from the bowl; c) a
heat resistant
and porous flame filter disposed in the filter housing, wherein the flame
filter has a thickness
of at least 0.05 inches, and wherein the flame filter comprises a material
selected from the
group consisting of open cell foam, bonded granules, stacked discs, tangled
wire, stacked
screens and combinations thereof.
According to a still further aspect of the present invention there is provided
a filter
unit for attachment to a pipe, comprising a) a filter housing; b) a heat
resistant and porous
flame filter, with tortured flow paths, disposed in the filter housing; c) a
means for attaching
the filter housing to the pipe.
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The present invention also may have a filter housing for holding the flaine
filter. The
filter housing can be made of thermally insulating material so that a user is
protected from
touching the hot flaine filter. The filter housing can also be hollow to
provide thermal
insulation.
The present invention also includes a filter unit having a filter housing, a
flaine filter
disposed in the housing, and a means for attaching the filter housing to a
pipe. The filter i.uzit
of the present invention can be used witll many different kinds and styles of
smoking pipes
and will transform conventional smoking pipe into a vaporization pipe. The
means for
attaching the pipe can be a threaded connection, magnet, clamp, hinge and the
like.
DESCRIPTION OF THE FIGURES
Fig. 1 shows a cross-sectional side view of a vaporization pipe according to
the present
invention.
Fig. 2 illustrates the present vaporization pipe in operation.
is Fig. 3 shows a close-up of a filter unit according to the present
invention.
Figs. 4a and 4b show an alternative embodiment of the invention having a
hinged filter
unit, and a straight pipe.
Fig. 5 shows an alternative embodiment of the invention having a friction-fit
filter
unit.
Fig. 6 shows an embodiment wherein the flame filter is a stack of screens
(metal or
ceramic).
Fig. 7 shows an embodiment wherein the flame filter is a tangled web of wire.
Fig. 8 shows a close-up of the filter unit wllere the flame filter comprises a
stack of 5
discs with holes.
Figs. 9 and 10 show top view of exemplary discs possible in the embodiment of
Fig. 9.
Fig. 11 shows a close-up of the filter unit where the flame filter is
coinbined with a
disc having holes that directs heat to the periphery of the flame filter.
Fig. 12 is a top view of an exemplary disc that can be used in the embodiment
of Fig.
11.
Fig. 13 shows an embodiment having an electronic temperature sensor and
temperature display.
Fig. 14 shows an embodiment having a mechanical airflow shutter responsive to
temperature for regulating temperature.
Figs. 15a and 15b show top views of an exemplary airflow shutter usable in the
embodiment of Fig. 14.
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Fig. 16 shows an embodiment having a theromechanical element for indicating
temperature inside the device.
DETAILED DESCRIPTION
The present invention provides a vaporizing pipe that vaporizes flavor
compounds and
psychoactive compounds from smoking material such as tobacco, inarijuana or
other
substances. The present vaporizer pipe can be used with a flaine such as from
a conventional
butane lighter or a match. The vaporization pipe of the present invention has
a heat resistant,
i o porous flame filter disposed upstreain from the smoking material. In
operation, flame exhaust
and ambient air are drawn into the flame filter. The flame filter causes
mixing between the
flame exhaust and ainbient air, and also conducts heat between the flame
exhaust and ambient
air. The flame filter thereby creates an intermediate temperature air stream
capable of
vaporizing without burning. The smoking material is in the path of the
intermediate
temperature air stream, and so volatile flavor and psychoactive compounds are
vaporized from
the smoking material. The intermediate temperature air stream and vaporized
compounds are
then inhaled. The flame filter can be made of many heat-resistant materials
such as metals
(e.g. refractory metals), ceramics and the like. The material of the flame
filter should be
resistant to oxidation at high temperature, resistant to extreme thermal
shock, and have a high
thermal conductivity. In preferred embodiments of the invention, the flame
filter comprises
reticulated ceramic foam.
Definitions:
Heat resistant: Capable of not melting and maintaining its physical structure
when
exposed to heat from a small flame. Materials that oxidize slightly when
exposed to flame
(e.g. bronze, stainless steel) are considered heat resistant in the invention.
However,
combustible materials (e.g. carbon) are not heat resistant.
Porous: Having a plurality of flow paths or pores that create mixing of
fluids.
Fig. 1 is a cross sectional side view of the present vaporization pipe. The
pipe has a
pipe bottom 20 having a hole 22 through which vapor is inhaled. The 'pipe has
an inhalation
end 24 for contact with a users mouth during use. The pipe also has a bowl 26
for holding
smoking material 28, such as tobacco, marijuana or the like. The bowl 26
preferably has a
mesh screen 30 for supporting the smoking material. A filter unit 34 is
removably attached to
the bowl 26 by threaded connection 32. The filter unit 34 has a heat-resistant
and porous
flame filter 36 and a filter housing 38 surroun.ding the flaine filter 36. The
filter unit 34 may
optionally have a heat shield 40 disposed between the filter housing 38 and
the flame filter 36.
The heat shield 40 can be a thin sheet (0.002") of stainless steel foil, for
example. A corner
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heat shield 41 can also be provided at an opening in the filter housing 38.
The corner heat
shield 41 and heat shield can comprise a single component. The corner heat
shield 41 helps
protect the filter housing 3 8 froin Raine. The filter unit 34 may make an
airtight seal with the
bowl 26, but an airtight seal is not absotutely required in the invention; a
small amount of air
leakage is permissible.
The pipe bottom 20 and filter housing 38can be made of many different
materials
such as wood, glass, ceramic, metal or the like. Materials with low thermal
conductivity such
as wood are generally preferred, but not required in the invention. The filter
housing 38 can
also be made of a material with low thermal conductivity so that heat from the
flame filter 36
does not escape to the exterior surfaces. Atternatively, the filter housing
has a hollow space
42 to provide low thermal conductivity. The pipe bottom 20 can also have a
hollow space
(not shown) for therinal insulation. The bowl 26 can be made of metal, in
which case it may
be plated with a relatively chem.ically nonreactive metal such. as silver,
gold, platinum or
chromium.
The present invention necessarily includes the porous flame filter 36. The
flame
filter is made of heat resistant material such as ceramic or metal (e. g.
refractory metal). The
flame filter is made of porous material. The flame filter can be made of many
structures, such
as open cell foam (ceramic or metal), sintered or bonded ceramic or met.al
granules, stacked
ceramic or metal screens or porous plates, or stacked discs with holes. If
plates are used, the
plates can each have many holes or a single hole. A stack of plates with holes
is considered
to be porous in the i.nvention, even if the plates are made of nonporous
material.
Fig. 2 shows the pipe of the present invention in. operation. In operation,
smoking
material 28 is disposed in the bowl. and a user (not showm) inhales air and
vaporization
products from the inhalation end 24, as indicated by arrow 44. Flatne 46 is
provided to the
flanle filter 36 by a lighter 48 or other flanie source, such as a match. The
flame may or may
not touch the flanie filter, but it is best for the flanie to be held slightly
above the flame filter
36. Hot exhaust from the flame 46 is drawn into the flame filter 36. Cold,
ambient air 50 is
also drawn into the flame filter. The flame filter 36 causes mixing between
the flame exhaust
and ambient air. I'he flame exhaust and ambient air, after mixing in the
filter 36, form an
intermediate-temperature ai:r stream 52 that flows over the smoking material.
The
intermediate-temperature air stream 52 can have a temperature of about 250-500
degrees
Fahrenheit, depending on a number of factors such as the speed of inhalation,
the size and
temperature of the flame 46, and the temperature of the ambient air. By
controlling the
application of flame to the flame filter 36 (e. g. lifting or lowering the
lighter), and the size of
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the flame, a user can modulate the teinperature of the air stream 52. With
experience, a user
can determine the temperature by taste and mouth sensations, and adjust the
amount of flame
accordingly to obtain a perfect temperature for vaporization.
Fig. 3 shows a close-up view of the filter unit 34 of the present invention.
The flame
s filter 36 has a thickness 54, which is measured in the directioii of airflow
througli the filter 36.
In the present invention, the flarne filter 36 must have a thickness'54 of at
least 0.02 inches. A
thiclcness of 0.02 inches is the absolute minimum required for at least
partially adequate
mixing between the flame exhaust and ambient air. If the filter is thinner
than 0.02 inches,
then the flame will tend to burn the smoking material. More preferably, the
flaine filter has a
thickness of at least 0.05 inches, 0.1 inches, 0.125 inches or 0.2 inches. A
thicker flame filter
provides more even heating of the smoking material. The flame filter will
typically have a
thiclcness in the range of about 0.25-0.75 inclies, but the thickness of the
filter can also be as
great as 1 or 2 inches or greater in the invention. The thickness of the
filter will depend
somewhat on the amount of mixing provided by the filter structure (e.g. pore
sizes), and the
is thermal conductivity of the filter material. High mixing capability (e.g.
small pore size) and
high thermal conductivity will allow for a thinner filter. Thicker filters are
required if the pore
size is large (e.g. 0.1 inch), and the filter has a low thermal conductivity
(e.g. below 10
W/mK)
The flaine filter 36 may be cylindrically shaped (although is not necessarily
,20 cylindrical), with a diameter 56. The diameter may be selected to be
within the range of about
0.125-0.75 inclles. The diameter of the flame filter 36 influences how much
ambient air is
admitted while inhaling. If the flame filter is very wide (e.g. a couple
inches), then a large
flame is required for adequately high temperature for vaporization. For flame
sizes typical of
conventional butane lighters (e.g., about 0.75-1 inch tall), it has been found
that the best
2s diameter is in the range of about 0.125 to 0.75 inches (i.e. cross
sectional area of about 0.015
square inch to about 1 square inch). The present invention includes
embodiments where the
flame filter is larger or smaller than this range, but in operating such
devices, care must be
taken to properly select the flame size. The present invention also includes
embodiments
where the flame filter is square, rectangular or any other shape in cross-
section.
30 The porous flame filter 36 is essential in the invention. The flame filter
36 can be
made of many different materials and structures, all of which are understood
to be included in
the invention and within the scope of the appended claims. Materials and
structures suitable
for the flame filter include:
Bonded granules--In this embodiment, the flame filter is made of granules of
heat
35 resistant materials bonded or sintered together. Exainples include sintered
bronze, brass,
stainless steel, or other metals. Also included are sintered ceramics such as
alumina,
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cordierite, or porcelain. Bonded silicon carbide granules can be used as well.
The granules can
have sizes in the range of about 100=2000 microns, for exainple. If metals are
used, a
chemically stable coating can be applied such as a gold or platinum to prevent
oxidation. The
porosity (volume % of open space) should be relatively high, for example at
least 20 or 30%.
The pore size should be relatively large so that one can inllale easily; for
example, the pore
size can be about 100-1000 microns.
Stack of plates or screens--The flaine filter can comprise a stack of at least
two,
preferably at least three or four metal screens. For example, conventional
metal screens can be
used. In this case, the metal should have a relatively high thermal
conductivity above about 30
W/mK (e.g. brass or silver). Also, the metal may be resistant to oxidation, or
have a protective
coating (e.g. platinum). Alternatively, the flame filter can comprise a stack
of at least two,
preferably at least three.or four ceramic or metal plates with holes. A series
of plates with
holes is considered to be 'porous' in the present invention and appended
claims.
Metal wire--The flame filter can also comprise a web of metal wire (e.g. 20-30
gauge). The metal may be resistant to oxidation or have a protective coating
(e.g. platiiium or
gold), and have a high thermal conductivity (e.g. copper, brass or silver).
The metal wire can
be tangled, coiled, folded of in any other configuration that creates mixing
of air and flame
exhaust.
Reticulated open-cell foam--The flame filter can also comprise open cell metal
or
ceramic foam. In this case, the foam can have a pores-per-inch (PPI) rating of
about 30-120,
more preferably in the range of 50-100 PPI, inclusive. If metal is used, it
should be heat
resistant, and possibly coated with a protective coating (e.g. gold, platinum
or other platinum-
family metals). If ceramic is used, the foam can be made by applying a ceramic
slurry to a
polymer (e.g. uretliane) foam substrate, and then kiln-firing, as known in the
art. Also, the
cerainic foam can be made by chemical vapor deposition (CVD) onto a foam
substrate, also as
lcnown in the art. If CVD ceramic foam is used, it can be made of silicon
carbide, which has
very high oxidation resistance and thermal shock capability, is relatively
inert, and has high
thermal conductivity, which are all desirable properties. CVD ceramic foam can
also be made
of silicon, which also has high thermal conductivity and heat resistance.
Other possible
materials for the ceramic foam include cordierite, zirconium-containing
ceramics, or silica-
containing cerainics, or combinations of these materials. Some cerainic
materials may break
apart or crack due to the thermal shock of the applied flame, which is
undesirable. Hence, a
ceramic material should be selected that can withstand the thermal shock. A
particularly
useful material for the flaine filter is 80 PPI CVD silicon carbide open-cell
foam about 0.25-
0.5 inches thick. The foam may have a relative density (volume occupied by
solid material) of
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about 5-25%. It is also iioted that not all of the cells need to be open; some
cells can be closed,
as often occurs in ceramic foam made from slurry applied to polyiner foam.
Most generally, the flame filter can coinprise any heat-resistant, porous
material that
causes mixing of the flame exhaust and air, and has a thicluiess of at least
0.02 inches, or at
least I millimeter or 0.1 inches. Reticulated structttres such as open cell
foanis are preferred,
but the invention includes all the materials listed above. The flame filter
should resist melting
up to at least the temperature of the flame of course, and preferably resists
oxidation up to
about 1000 degrees Fahrenheit. Some oxidation is acceptable if it forms a
protective coating.
Also, the material of the flame filter (i.e. not including pore spaces), may
have a thermal
conductivity of at least 30 W/mK. Silicon carbide can have thermal
conductivity of about 120
W/mK, and so provides good heat transfer. A high thermal conductivity
facilitates heat
transfer between the flame exhaust and ambient air, thereby ensuring that the
intermediate
temperature air stream has a uniform temperature.
The flame filter can have a protective coating (e.g. platintun) to protect it
from
oxidation and chemical reactions. A protective coating can be particularly
useful in
einbodiments employing metals, such as metal wire or sintered metal granules.
It is also noted that the flame filter 36 can have a combustion catalytic
coating (e.g.
platinum) for causing more complete cornbustion of the flame exhaust. This
will tend to
reduce the amount of harmful combustion products inhaled from the flame.
Also, it is noted that the filter can include means (e.g. threads, friction
fit) for direct
attachment to the pipe. Preferably, the flame filter is disposed in a filter
housing, because the
flame filter typically gets too hot to safely handle. If a filter housing is
used, the flame filter
can be attaclled to the pipe indirectly through the filter housing. It is
understood that the flame
filter is considered attached to the pipe even in embodiments where the flame
filter is directly
attached only to the filter housing.
It is noted that the filter unit 34 can attach to the pipe with many different
mechanisms.
Exainples include magnetized components that attach by magnetic attraction,
screw threads as
shown in Figs 1 and 2, friction fit, with or without O-rings, hinges, spring
clamps and the like.
Figs. 4a and 4b illustrate an alternative embodiment of the invention where
the filter
unit 34 is attached to a straight pipe 55 with a hinge 56. The hinge allows
the smoking
material 28 to be inserted, and removed when it is spent. It is tuiderstood
that a hinge
attachment is considered to be an example of a'removable' attachnient in the
present invention
and appended claims.
Fig. 5 shows an alternative embodiment where the filter unit 34 is attached to
the
straight pipe by sliding over the straight pipe 55 with a friction fit. An 0-
ring (not shown) can
be disposed between the filter housing 38 and the straight pipe 55.
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Fig. 6 shows an embodiment of the invention having a stack of 6 screens 58 as
the
flame filter. The screens can be made of metal mesh, for example, or cerainic.
The filter unit
34 fits onto a pipe 57 witli a friction fit, for example. The screens 58 may
be spaced apart as
shown, or may be in contact. A series of screens is considered to be 'porous'
in the invention.
Fig. 7 shows an embodiment wllere the flame filter coinprises a web of metal
wire 60.
The wire can be 20-30 gauge, for exainple. The wire can be tangled, as shown,
or can be
coiled or folded in an organized fashion.
Fig. 8 shows a close-up of the filter unit 34 in an einbodiment where the
porous flame
filter comprises a series of 5 discs 61 a-61 e, with each disc having holes
64. The discs can be
made of metal or ceramic or any other heat-resistant material, for example.
The discs have
holes in different locations, so that ambient air and flame exhaust follow a
tortured patli 62.
The tortured path creates mixing between the flame exhaust and the ambient
air, as required in
the present invention. The disc material may or may not be porous, but the
combination of
stacked discs is considered porous in the invention. The number is discs can
be in the range of
about 3-20, for example.
Fig. 9a shows a group of 5 discs that can be used in the embodiment of Fig. 8.
Each
disc has the same hole pattern, but each disc is rotated so that the holes in
adjacent discs are
not overlapping. This assures that the flame exhaust and ambient air follow a
tortured path
and are mixed as they pass between the discs. Fig. 10 shows an alternative
group of discs 61
having elongated holes 64 arranged in a striped pattern. The discs can be
round (as shown), or
square, rectangular or any other shape.
Fig. 11 shows yet another embodiment of the filter unit 34 wherein the flame
filter 36
is combined with a disc 70 over the flame filter 36. The disc 70 has holes 72
around the
periphery. The holes 72 are located at the periphery, and so tend to direct
heat toward the
periphery of the filter, and thereby create a more uniform heat distribution
in the smoking
material. Without the disc 70, sometimes the teinperature can be too hot in
the center, and too
low at the edges. Fig. 12 shows a top view of the disc. The disc can have any
nuinber of holes
(e.g. 3-10), and the holes can be any shape. The disc 70 can also be located
under (on the
downstream side of) the flame filter 36. The embodiment of Figs. 11 and 12 is
most useful
where the flame filter 36 comprises a reticulated structure such as a foam or
bonded granules.
In an alternative embodiment, the disc 70 has no holes, and has a smaller
diameter than the
flaine filter 36, so that it directs airflow to the periphery. The disc 70 can
be bonded to the
flaine filter 36.
Fig. 13 shows another embodiment having an electronic temperature indicator 80
coupled to a temperature sensor 82 such as a thermistor or thermocouple. The
temperature
sensor 82 should be located close to the smoking material 28. The temperature
sensor can be
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located behind (downstream from) the smoking niaterial, as shown, or can be
located between
the flame filter 36 and the smoking material 28. In operation, the display 80
provide the user
with an indication of the temperature at the smoking material. This is useful
for some users
who have difficultly adjusting the flaine application to achieve the best
vaporization
s temperature. The display may have an LED, or liquid crystal element to
indicate an
approximate temperature to the user, for example with a bar display. By using
the display, the
user can more accurately adjust the teinperature inside the smoking material
28.
Fig. 14 shows anotlzer aspect of the invention wherein the pipe includes a
thermo-
mechanical airflow shutter 84 for controlling airflow in response to
temperature. In the present
vaporization pipe, the amount of airflow influences the teinperature at the
smoking material.
Specifically, for a constant flame size, higher airflow (stronger inhalation)
results in cooler
temperature, since higher airflow requires more ambient air. Hence, the
thermomechanical
shutter 84 can maintain a somewhat constant teinperature by restricting
airflow when
temperature is too low. More specifically, the shutter 84 opens when is it
exposed to excessive
temperature (e.g. temperatures that can cause burning), thereby allowing more
ambient air,
and reducing the temperature. The shutter can be made of a bimetallic strip
partially blocking
the air passage. When exposed to high teinperature, the shutter 84 bends to
open the airway.
Many different shapes and structures casi be used for the shutter 84. Figs.
15a and 15b, for
example, show top views of a sllutter made of bimetallic sheet at low and high
temperature,
respectively. Leaves 86 of the shutter curl in a direction out of the page
when exposed to
excessive temperature, and thereby allow more airflow when exposed to
excessive
temperature. The shutter 84 can be located between the flame filter 36 as
shown, or can be
placed below the smoking material 28 (i.e., within the pipe bottom). In an
alternative
embodiment, the shutter allows air directly from ambient (not through the
flame filter), when
the temperature is excessive.
Fig. 16 shows yet another embodiment of the invention having a temperature
indicator.
Specifically, the device has a thermomechanical element (e.g. bimetallic
strip) 86 that
responds to temperature by raising or lowering a rod 88 through a hole 90. The
height of the
rod 88 indicates the approximate temperature experienced by the smoking
material 28.
The present invention is also directed toward only the filter unit, which has
a flame
filter inside the filter housing, and a means for attaching the filter housing
to a pipe. The
present filter unit can be used with many different kinds of pipes and devices
ordinarily
intended for use as conveiitional smoking devices. In fact, the present filter
unit can
effectively transform a conventional smoking device into a vaporization
device. For example,
the filter unit can be combined with a water pipe ("bong") or any other pipe
known in the art,
and the pipe will act as a vaporizer.
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It is also noted that the present invention can be used to produce smoke, if
desired. If
smoke is desired, a large flame is provided to the flaine filter. Smoke
produced in the present
device will tend to be smoother and more pleasant than smoke produced in a
conventional
pipe, but will contain the harnzful substances known to occur in smoke.
It is noted in the present invention that ceramic materials are generally
preferred over
metals for use in the flaine filter 36. This is because ceramics tend to be
much more resistant
to oxidation and corrosion at high temperatures. Metals such as brass, copper
or bronze tend
to oxidize, which produces unhealtliful metal oxide particles, which are
inhaled. Also, metal
flame filters tend to create a metallic taste. Inert metals such as platinuin
or gold can be used
(e.g. as a coating), but such materials are very expensive. Hence, inert
ceramics such as silicon
carbide, silicon, cordierite, and zirconia are preferred. It is also noted
that semiconductor
materials such as silicon can be used for the flaine filter (e.g. silicon
foam), and such materials
are understood to fall under the rubric of ceramic materials in the present
disclosure.
Nevertheless, it is understood that even oxidizable metals (e.g. brass,
bronze, steel) will
ls function to provide flame filtering and air mixing, and are therefore
included in the present
invention and scope of the appended claims.
It will be clear to one skilled in the art that the above embodiments may be
altered in
many ways without departing from the scope of the invention. Accordingly, the
scope of the
invention should be determined by the following claims and their legal
equivalents.
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