U.S. patent number RE33,282 [Application Number 07/136,594] was granted by the patent office on 1990-07-31 for liquid gas-operated lighter.
This patent grant is currently assigned to BIC Corporation. Invention is credited to Friedrich Schachter.
United States Patent |
RE33,282 |
Schachter |
July 31, 1990 |
Liquid gas-operated lighter
Abstract
Liquid gas-operated lighter, particularly pocket lighter,
comprising a burner tip, a fuel tank, and, arranged therebetween, a
non-adjustable control device for the flame height. The control
device is provided with a fuel-permeable proportioning disk of
microporous film which, on the side facing the fuel tank, is
tightly braced in its border region by means of a bracing disk
having a passage for the fuel, and, on the side facing the burner
tip, rests against a component having a gas-permeable layer, the
bracing disk (15) forming the conclusion of the lower end of the
control device (12, 13, 14, 15, 16). In the vertical position of
use of the lighter, this end is always located at a distance above
the liquid phase of the liquid gas. The space between the control
device and the liquid level (21) is free from structural
components.
Inventors: |
Schachter; Friedrich (Vienna,
AT) |
Assignee: |
BIC Corporation (Milford,
CT)
|
Family
ID: |
3578987 |
Appl.
No.: |
07/136,594 |
Filed: |
December 21, 1987 |
PCT
Filed: |
November 23, 1981 |
PCT No.: |
PCT/AT81/00028 |
371
Date: |
July 23, 1982 |
102(e)
Date: |
July 23, 1982 |
PCT
Pub. No.: |
WO82/01932 |
PCT
Pub. Date: |
June 10, 1982 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
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Reissue of: |
403499 |
Nov 23, 1981 |
04560345 |
Dec 24, 1985 |
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Foreign Application Priority Data
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Nov 24, 1980 [AT] |
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5726/80 |
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Current U.S.
Class: |
431/344 |
Current CPC
Class: |
F23Q
2/163 (20130101) |
Current International
Class: |
F23Q
2/16 (20060101); F23Q 2/00 (20060101); F23D
013/04 () |
Field of
Search: |
;431/131,344 ;222/3
;251/120,121 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
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1457631 |
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Oct 1969 |
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DE |
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2622096 |
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Dec 1976 |
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DE |
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2313638 |
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Jun 1975 |
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FR |
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2303239 |
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Oct 1976 |
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FR |
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2444891 |
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Aug 1980 |
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FR |
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Primary Examiner: Green; Randall L.
Attorney, Agent or Firm: Pennie & Edmonds
Claims
I claim:
1. Liquid gas-operated lighter, such as pocket lighter, comprising
a burner tip, a fuel tank and, arranged therebetween, a valve
assembly serving as the only means of communication between said
fuel tank and said burner tip, an annular flange formed at an end
face of said valve assembly facing said fuel tank, said flange
defining a recess, said valve assembly including a valve bore
opening to said recess communicating with said valve, a control
device for the flame height which device is non-alterable by the
user of the lighter, said control device received in said recess
and including a fuel-permeable proportioning disk, said
proportioning disk tightly braced in its border region toward said
end face by means of a bracing member so that gas is enabled to
flow only through said proportioning disk, the border region formed
between said end face and said bracing member is rendered
permanently gas-tight, said bracing member secured in its position
by securing means formed on said flange and provided with passage
means for the fuel, said proportioning disk on the side facing said
burner tip facing a gas-permeable layer, characterized in that said
proportioning disk is a microporous film having slot-shaped pores
oriented in the direction perpendicular to the surface of said
disk, and that said bracing member (15) together with said flange
forms the conclusion of the lower end of said control device (12 to
16) and, in the vertical position of use of said lighter, said
lower end is always spaced at a distance above the liquid phase of
the liquid gas, and that the space between said lower end and the
liquid level (21) is free from structural components, so that said
lower end of said control device is exposed exclusively to the
gaseous phase of the fuel in the vertical position of use of the
lighter.
2. Lighter according to claim 1, characterized in that said lower
end of said control device projects out of the material forming
said fuel tank (1) into the interior of said fuel tank, and that
the length of the portion projecting into the interior of said fuel
tank essentially corresponds to the depth of said recess (12) in
said valve assembly which receives said proportioning disk and said
bracing member.
3. Lighter according to claims 1 or 2, characterized in that the
surfaces and spaces of said lower end of said control device
projecting into said fuel tank (1) have such a size and volume that
the amount of the liquid fuel which adheres to said components due
to surface forces after said lighter has been moved from an
essentially horizontal carrying position when said lighter is moved
into the usual, vertical position of use, is smaller than the
amount of fuel consumed by the normal flame within three
seconds.
4. Lighter according to claim 3, characterized in that the amount
of fuel adhering to said components is smaller than the amount of
fuel consumed by the normal flame within less than one second.
5. Lighter according to claim 1, characterized in that at least the
surface of said bracing member (15) facing said fuel tank (1) is
constructed so as to be fuel-repellent.
6. Lighter according to claim 1, characterized in that the
thickness of said bracing member (15) is smaller than the diameter
of the surface area of said proportioning disk (14) permitting
passage of fuel therethrough.
7. Lighter according to claim 6, characterized in that the
thickness of said bracing member is smaller than half said diameter
of said proportioning.
8. Lighter according to claim 1, characterized in that said bracing
member (15) consists of a metal material.
9. Lighter according to claim 8, characterized in that said metal
material is machining brass.
10. Lighter according to claim 1, characterized in that a hollow
space is defined between an unbraced area of said proportioning
disk and said bracing member permitting passage of fuel.
11. Lighter according to claim 1, characterized in that on the side
of said proportioning disk (14) facing said burner tip said gas
permeable layer comprising a non-woven fiber material layer (13)
having approximately the same size is provided.
12. Lighter according to claim 11, characterized in that on the
side of said non-woven fiber material layer (13) facing said burner
tip an intermediate layer (18,19') of plastics material is provided
at least corresponding to said border region of said proportioning
disk (14).
13. Lighter according to claim 12, characterized in that said
plastics material is polyimide.
14. Lighter according to claim 1, characterized in that said
proportioning disk (14) consists of a microporous, uniaxially
stretched polypropylene film.
15. Lighter according to claim 14, characterized in that said film
is "Celgard.RTM.2500".
16. Liquid gas-operated lighter, such as pocket lighter, comprising
a burner tip, a fuel tank and, arranged therebetween, a valve
assembly serving as the only means of communication between said
fuel tank and said burner tip, an annular flange formed at an end
face of said valve assembly facing said fuel tank, said flange
defining a recess, said valve assembly including a valve bore
opening to said recess and communicating with said valve, a control
device for the flame height which device is non-alterable by the
user of the lighter, said control device received in said recess
and including a fuel-permeable proportioning disk, said
proportioning disk tightly braced in its border region toward said
end face by means of a bracing member so that gas is enabled to
flow only through said proportioning disk, the border region formed
between said end face and said bracing member is rendered
permanently gas-tight, said bracing member secured in its position
by securing means formed on said flange and provided with passage
means for the fuel, said proportioning disk on the side facing said
burner tip facing a hollow space, the cross-sectional area of said
hollow space perpendicularly to the axis of said proportioning disk
determining the position and size of the surface of said
proportioning disk which permits passage of fuel therethrough,
characterized in that said proportioning disk is a microporous film
having slot-shaped pores oriented in the direction perpendicular to
the surface of said disk, and that said bracing member (15)
together with said flange forms the conclusion of the lower end of
said control device (12 to 16) and, in the vertical position of use
of said lighter, said lower end is always spaced at a distance
above the liquid phase of the liquid gas, and that the space
between said lower end and the liquid level (21) is free from
structural components, so that said lower end of said control
device is exposed exclusively to the gaseous phase of the fuel in
the vertical position of use of the lighter.
17. Lighter according to claim 16, characterized in that said end
face (2') is roughened in order to permit fuel flow from said
proportioning disk toward said valve bore.
18. Lighter according to claim 16, characterized in that said end
face (2') has a distance from said proportioning disk which limits
the yielding of said proportioning disk (14) under the influence of
the pressure acting on it.
19. Lighter according to claim 16 or 18, characterized in that in
said hollow space (16) is arranged a disk (13) of non-woven fiber
material .[.said.]. .Iadd.forming of .Iaddend.gas-permeable layer,
the thickness of said disk of non-woven material being smaller than
the distance of said end face (2') from said proportioning disk
(14).
20. Lighter according to claim 16 characterized in that said
proportioning disk (14) consists of a microporous, uniaxially
stretched polypropylene film.
21. Lighter according to claim 20 characterized in that said film
is "Celgard.RTM.2500". .Iadd.
22. Liquid gas-operated lighter, such as a pocket lighter,
comprising a burner tip, a fuel tank and, arranged therebetween, a
valve assembly serving as the only means of communication between
said fuel tank and said burner tip, an annular flange formed at an
end face of said valve assembly facing said fuel tank, said flange
defining a recess, said valve assembly including a valve bore
opening to said recess and communicating with said valve, a control
device for the flame height which device is non-alterable by the
user of the lighter, said control device received in said recess
and including a fuel-permeable proportioning disk, said
proportioning disk tightly braced in its border region toward said
end face by means of a bracing member so that gas is enabled to
flow only through said proportioning disk, the border region formed
between said end face and said bracing member is rendered
permanently gas-tight, said bracing member secured in its position
by securing means formed on said flange and provided with passage
means for the fuel, said proportioning disk on the side facing said
burner tip directly facing a hollow space in the absence of a gas
permeable structural component, the cross-sectional area of said
hollow space perpendicularly to the axis of said proportioning disk
determining the position and size of the surface of said
proportioning disk which permits passage of fuel therethrough,
characterized in that said proportioning disk is a flexible
microporous film having slot-shaped pores oriented in the direction
perpendicular to the surface of said disk, said slot-shaped pores
directing said gas into said hollow space which space comprises
means for passage of said gas into said valve bore, and that said
bracing member together with said flange forms the conclusion of
the lower end of said control device and, in the vertical position
of use of said lighter, said lower end is always spaced at a
distance above the liquid phase of the liquid gas, and that the
space between said lower end and the liquid level is free from
structural components, so that said lower end of said control
device is exposed exclusively to the gaseous phase of the fuel in
the vertical position of use of the lighter. .Iaddend. .Iadd.23.
The lighter of claim 22 wherein the microporous film is a
uniaxially stretched polypropylene film having a thickness of
between 15 and 39 microns. .Iaddend. .Iadd.24. The lighter of claim
23 wherein the microporous film is "Celgard.RTM. 2500". .Iaddend.
.Iadd.25. The lighter of claim 22 wherein said gas passage means is
provided by a roughened end face in the region of said hollow
space. .Iaddend. .Iadd.26. The lighter of claim 22 wherein said gas
passage means is provided by a separate non-woven fiber material
layer which is located only in said hollow space. .Iaddend.
.Iadd.27. The lighter of claim 22 wherein the hollow space is
defined by a cross-sectional area of a depth which is minimized in
order to prevent irreversible deformation of said microporous film.
.Iaddend. .Iadd.28. The lighter of claim 22 wherein the thickness
of the bracing member is not greater than the hydraulic diameter of
the hollow space.
.Iaddend. .Iadd.29. The lighter of claim 22 wherein the thickness
of said bracing member is smaller than half the diameter of said
proportioning. .Iaddend. .Iadd.30. The lighter of claim 22 wherein
about 20% of the capacity of the fuel tank is occupied by the
gaseous phase of the fuel and that the components serving to brace
the proportioning disk do not come in contact with the liquid level
of the fuel. .Iaddend. .Iadd.31. The lighter of claim 22 wherein
said bracing member and said end face (2') are each made of metal
having substantially flat opposed surfaces which are forced toward
each other by said securing means to tightly brace the border
region of said proportioning disk in a gas-tight manner. .Iaddend.
.Iadd.32. The lighter of claim 22 wherein the surfaces and spaces
of said lower end of said control device projecting into said fuel
tank have such a size and volume that the amount of the liquid fuel
which adheres to said components due to surface forces after said
lighter has been moved from an essentially horizontal carrying
position when said lighter is moved into the usual, vertical
position of use, is smaller than the amount of fuel consumed by the
normal flame within three seconds. .Iaddend. .Iadd.33. The lighter
of claim 32, wherein the amount of fuel adhering to said components
is smaller than the amount of fuel consumed by the normal flame
within less than one second. .Iaddend. .Iadd.34. Liquid
gas-operated lighter, such as a pocket lighter, comprising a burner
tip, a fuel tank and, arranged therebetween, a valve assembly
serving as the only means of communication between said fuel tank
and said burner tip, an annular flange formed at an end face of
said valve assembly facing said fuel tank, said flange defining a
recess, said valve assembly including a valve bore opening to said
recess and communicating with said valve, a control device for the
flame height which device is non-alterable by the user of the
lighter, said control device received in said recess and including
a fuel-permeable proportioning disk, said proportioning disk
tightly braced in its border region toward said end face by means
of a bracing member so that gas is enabled to flow only through
said proportioning disk, the border region formed between said end
face and said bracing member is rendered permanently gas-tight,
said bracing member secured in its position by securing means
formed on said flange and provided with passage means for the fuel,
said proportioning disk on the side facing said burner tip directly
facing a hollow space, the cross-sectional area of said hollow
space perpendicularly to the axis of said proportioning disk
determining the position and size of the surface of said
proportioning disk which permits passage of fuel therethrough,
characterized in that said proportioning disk is a flexible
microporous film having slot-shaped pores oriented in the direction
perpendicular to the surface of said disk, said slot-shaped pores
directing said gas into said hollow space, which space is
constructed to allow passage of said gas into said valve bore from
areas surrounding said valve bore when the film is deformed, and
that said bracing member together with said flange forms the
conclusion of the lower end of said control device and, in the
vertical position of use of said lighter, said lower end is always
spaced at a distance above the liquid phase of the liquid gas, and
that the space between said lower end and the liquid level is free
from structural components, so that said lower end of said control
device is exposed exclusively to the gaseous phase of the fuel in
the vertical position of use of the lighter. .Iaddend. .Iadd.35.
The lighter of claim 34 wherein the microporous film is a
uniaxially stretched polypropylene film having a thickness of
between 15 and 39 microns. .Iaddend. .Iadd.36. The lighter of claim
35 wherein the microporous film is "Celgard.RTM. 2500". .Iaddend.
.Iadd.37. The lighter of claim 34 wherein the hollow space is
defined by a cross-sectional area of a depth which is minimized in
order to prevent irreversible deformation of said microporous film.
.Iaddend. .Iadd.38. The lighter of claim 34 wherein the areas
surrounding said valve bore are provided with means for passage of
said gas from said deformed film to said valve bore. .Iaddend.
.Iadd.39. Liquid gas-operated lighter, such as a pocket lighter,
comprising a burner tip, a tank for fuel in the liquid and gaseous
states and, arranged therebetween, a valve assembly serving as the
only means of communication between said fuel tank and said burner
tip, an annular flange formed at an end face of said valve assembly
facing said fuel tank, said flange defining a recess, said valve
assembly including a valve bore opening to said recess and
communicating with said valve, a control device for the flame
height which device is non-alterable by the user of the lighter,
said control device received in said recess and including a
fuel-permeable proportioning disk, said disk tightly braced in its
border region against the periphery of said end face by means of a
bracing member so that fuel is enabled to flow only through said
disk, the border region formed between said end face and said
bracing member being rendered permanently non-permeable for fuel,
said bracing member secured in its position by means formed on said
flange and provided with passage means for the fuel, said disk on
the side facing said burner tip directly facing a hollow space, the
cross-sectional area of said hollow space perpendicularly to the
axis of said disk determining the position and size of the surface
of said disk which permits passage of fuel therethrough,
characterized in that said disk is a flexible microporous film
having substantially discrete pores for providing fuel passage in
the direction perpendicular to the surface of said disk, said pores
being of slot-shaped cross-section and directing said fuel into
said hollow space, which space is constructed to allow passage of
said fuel into said valve bore even from areas within said hollow
space where fuel after passing through said disk would otherwise
remain trapped due to said film deforming and contacting opposite
portions inside said braced periphery of said end face, and that
said bracing member together with said flange forms the conclusion
of the lower end of said control device and, in the vertical
position of use of said lighter, said lower end is always spaced at
a distance above the liquid phase of the fuel, and that the space
between said lower end and the liquid level is free from structural
components, so that said lower end of said control device is
exposed exclusively to the gaseous phase of the fuel in the
vertical position of use of the lighter. .Iaddend. .Iadd.40. The
lighter of claim 39 wherein the microporous film is a uniaxially
stretched polypropylene film having a thickness of between 15 and
39 microns. .Iaddend. .Iadd.41. The lighter of claim 40 wherein the
microporous film is "Celgard.RTM. 2500". .Iaddend. .Iadd.42. The
lighter of claim 39 wherein, with the exception of said microporous
film, all components of the lower end of said control device are
made of metal, said components holding said disk tightly braced in
its border region in order to enable gas to flow only through said
disk from said fuel tank to said burner tip, said lower end of said
control device projecting into said fuel tank and that the amount
of liquid fuel which adheres to said components when said lighter
is moved into a vertical operational position is less than two
cubic millimeters and the amount of fuel passing through said disk
during operation of the lighter produces a flame height of about 25
mm. .Iaddend.
Description
BACKGROUND OF THE INVENTION
The invention relates to a liquid gas-operated lighter,
particularly pocket lighter, comprising a burner tip, a fuel tank
and, arranged therebetween, a non-adjustable control device for the
flame height which is provided with a fuel-permeable proportioning
disk of microporous film. On its side facing the fuel tank, the
proportioning disk is tightly braced in its border region by means
of a bracing disk which is provided with a passage for the fuel
and, on its side facing the burner tip, the proportioning disk
rests against a structural component having a gas-permeable
layer.
In pocket lighters, particularly in those having no adjustable
flame regulator, manufacturing inconsistencies lead to a great
problem with respect to keeping the flame height constant,
particularly with respect to achieving a uniform burning of the
flame. Moreover, due to the fact that the vapor pressure of the
fuel depends upon the temperature, the amount of gas discharged
and, therefore, the flame height change as the temperature changes.
For example, assuming a normal flame with a height of 25 mm at
25.degree. C., a temperature change of about 10.degree. C. results
in a change of the flame height of about 10 mm, about 1 milligram
fuel per second being consumed at a flame height of 25 mm when
using, for example, isobutane gas. When the temperature influences
are compounded with the manufacturing inconsistencies, unexpectedly
high flames may frequently occur, which represent a safety
risk.
In lighters having a wick or an ascending pipe, and in lighters in
which the fuel tank contains air whose pressure is higher than the
vapor pressure of the liquid gas, a decrease of the liquid level
with increasing consumption also leads to a change of the flame
height. Experience has shown that in known lighters even the aging
in the unused state leads to a change of the originally adjusted
flame characteristic. This is particularly true when the lighters
are subjected to changing or extreme ambient conditions.
Also, a flickering of the flames can be frequently observed. This
is particularly true for pocket lighters which are subjected to
very different temperatures, on the one hand, and which are
frequently in a completely undefined carrying position immediately
prior to being used.
In these devices, the relative constancy of the flame height is
also primarily a safety problem because unexpectedly high flames
may lead to burns or to the unintentional igniting of objects.
Because of the importance of this problem, even non-refillable
lighters, or so-called disposable lighters, practically without
exception have adjustable flame regulators, which substantially
increases their manufacturing costs. Nevertheless, the problem of
exceeding the permissible maximum flame height is not
satisfactorily solved in this manner. Therefore, several countries
are considering introducing legal limitations for such
products.
A vast majority of the conventional gas lighters are provided with
porous bodies serving as flow-control elements for the fuel. These
flow-control elements are simultaneously used for regulating the
flame height. Inasmuch as they are bodies made of fibers, the
amount of fuel passing therethrough can be regulated by an
appropriate compression of the body; the stronger the body is
compressed, the lower becomes the amount flowing through. If the
flow-control bodies consist of rigid, porous materials, such as,
sintered material, the amount flowing through is regulated by
covering the surface of the portions of the body exposed to the
fuel by elastically deformable elements. However, it is also known
to conduct the fuel through a narrow bore of a rubber-elastic
element toward the burner tip and to regulate the amount flowing
through by radially deforming the rubber body by applying an axial
pressure, thereby reducing the diameter of the small bore serving
as passage.
In these cases, the compression is adjusted during the manufacture
of the lighters in such a way that the flame has a permissible
height. It is left to the user to adjust a flame height deviating
therefrom.
It may happen in pocket lighters that a dangerously high flame
occurs at the time of ignition or during the adjustment of the
flame height, which causes small droplets of liquid gas to be
entrained by its gas phase, resulting in flickering of the flame.
Therefore, it is desirable to limit the amount of fuel discharged.
It is known that such a limitation can be achieved by a certain
microporous plastics film. Such a film can be provided either
instead of a flame regulating mechanism or in addition thereto, as
shown by French Pat. Nos. 2,313,638 and 2,313,639. In these
lighters, the porous film separates a wetting chamber from a
vaporization chamber. In these lighers, it must be ensured that
liquid fuel wets the membrane on the side of the film exposed to
the fuel, for which purpose wicks or dip pipes are provided. As a
result, the manufacture of these lighers becomes more complicated
and more expensive.
It is the object of the invention to provide a simple structural
design of lighters, which leads to a low reject rate in the mass
production of such pocket lighters (disposable lighters). By
decreasing the number of structural components, the manufacturing
costs are reduced.
The invention resides in the finding, contrary to the prevailing
view, that a uniform flame whose height is limited can be achieved
even during long burning durations, when fuel is present in the
gaseous state on the side of the membrane exposed to the fuel.
However, the practical embodiment poses difficulties because the
uncontrolled position of the lighter between uses always causes
liquid fuel to reach the membrane and to wet the latter. Therefore,
it must be ensured that the liquid fuel quickly runs off from the
membrane into the tank when the lighter is positioned vertically
into its position of use and that only a non-avoidable amount of
liquid fuel remains in the region of the membrane. Therefore, the
basic concept of the invention resides in constructing the size and
shape of the structural components of the control device facing the
interior of the fuel tank in such a way that as little as possible
liquid fuel is retained by surface forces.
In the above-described pocket lighters having a control device, the
latter has a bracing disk which tightly presses together in its
border region the proportioning disk which also consists of
microporous film, so that only the surface area free from
compression action is available for the passage of the fuel. Such a
control device meets the requirements for achieving the object of
the invention if, in accordance with the invention, the bracing
disk forms the conclusion of the lower end of the control device,
and when, in the vertical position of use of the lighter, this end
is always situated at a distance above the liquid phase of the
liquid gas and the space between the control device and the level
of the liquid is free from structural components.
Surprisingly, the construction of the control device in accordance
with the invention results in a very uniformly burning flame and,
furthermore, the lighters leaving the manufacturing plant have
insignificant inconsistencies with respect to the flame height.
Since the lighters have no regulating mechanism for adjusting the
flame height, it is particularly important that the flame height
resulting from the manufacture of the lighters is as uniform as
possible and corresponds to the normal flame height of 25 mm at
298.degree. K.
An advantageous embodiment results when the surfaces and spaces of
the control device and its housing facing the fuel tank and
facilitating the adherence of the liquid fuel have such a size and
volume that the amount of liquid fuel which adheres to these
structural components due to surface forces when the lighter is
moved into the normal, vertical position of use, is smaller than
the amount of fuel consumed by the normal flame within three
seconds, preferably within less than one second.
For improving the desired effects, the surfaces, particularly those
of the bracing disk, can be provided with a coating which repels
the liquid fuel.
The invention further relates to the structural design and the
selection of material for the proportioning disk, bracing disk and
the structural component having a gas-permeable layer. In the
following, several embodiments of the invention shall be described
with the aid of the drawing, without limiting the invention to
these embodiments.
BRIEF DESCRIPTION OF THE DRAWING
FIG. 1 is a partial sectional view of a lighter in accordance with
the invention which is equipped with a non-adjustable control
device for keeping the flame height constant. For clarity's sake,
all those parts which are not necessary for the explanation of the
invention are not illustrated.
FIGS. 2 through 10 are cross-sectional views through various
advantageous embodiments of the control device.
DETAILED DESCRIPTION OF THE INVENTION
In accordance with FIG. 1, a valve member 2 is pressed in a
gas-tight manner into the upper wall of a liquid-gas tank 1. In a
bore on the side facing away from the tank, the valve member 2
receives a displaceable burner pipe 3. At its upper end, the burner
pipe 3 has a burner tip 4 underneath which an actuating lever 5
engages. A bore 8 within the burner pipe 3 extends from an outlet 6
to a transverse bore 7. At the lower end of the burner pipe 3, a
sealing disk 9 is arranged which interacts with a valve seat 10 of
the valve member 2. When the lighter is not used, the actuating
lever 5 presses the burner pipe 3 toward the bottom against the
valve seat 10 with the aid of a spring, not shown, and thereby
closes a valve bore 11.
At its side facing the tank 1, the valve member 2 has an annular
flange forming recess 12 against whose end face is placed a
non-woven fiber material layer 13 which forms the component having
the gas-permeable layer. Underneath the non-woven fiber material
layer 13 is arranged a proportioning disk 14 which is pressed
against the non-woven fiber material layer by a bracing disk 15, so
that the bracing surface is substantially closed in a gas-tight
manner. A hollow space 16 is arranged in the bracing disk 15. The
hollow space 16 is connected to the tank 1 via an opening 17.
The recess 12, the non-woven fiber material layer 13, the
proportioning disk 14, the bracing disk 15 and the hollow space 16
form the control device in accordance with the invention.
The proportioning disk 14 is composed of a microporous plastics
film which is permeable in the direction of the surface normal for
the liquid and the gaseous phases of the liquid gas. Particularly
suitable is a microporous, uniaxially stretched polypropylene film
having a thickness of between 10 and 100 .mu.m, preferably between
15 and 39 .mu.m, and having slot-like pores oriented in the
stretching direction. Such a product is sold at the present time,
inter alia, by Celanese Corp., U.S.A., under the tradename
"Celgard.RTM.2500". Preferably, the thermal expansion coefficient
of the proportioning disk 14 is close or equal to that of the
bracing disk 15.
The non-woven fiber layer 13 has a thickness of 20 to 200 .mu.m,
preferably 20 to 50 .mu.m. Particularly suitable for this purpose
are textile laminated materials of non-woven polypropylene fibers,
manufactured either according to the melt-air-blow method or the
spinbond method. Particularly the melt-air-blow method provides
very uniform laminated materials. A particular advantage of the
non-woven fiber material layer 13 resides in the alleviation of
mechanical instabilities of the proportioning disk 14, such as,
periodic fluttering.
The proportioning disk 14 and the non-woven fiber material layer 13
are braced into the recess 12 by means of the bracing disk 15 in
such a way that the bracing surface forms a gas-tight closure. The
bracing disk 15 is fixed by flanging the rim of the recess 12. It
is advantageous to make the valve member 2 of a metal material,
preferably of machining brass, because the high compressive
strength of such materials facilitates a reliably tight
closure.
In accordance with FIG. 1, the hollow space 16 in the bracing disk
15 is provided in its side facing the proportioning disk 14.
However, it can also be formed in a different manner and it can
also be located on the side of the proportioning disk 14 facing
away from the tank 1. The cross-sectional area of the hollow space
16 perpendicularly to the axis of the proportioning disk 14
determines the size, position and shape of the surface of the
proportioning disk 14 exposed to the fuel. Generally, this surface
will be circular. However, it can also have another shape. In the
latter case, the diameter of a circular area of equal size is
designated the hydraulic diameter of the surface deviating from the
circular shape. The thickness of the bracing disk 15 is smaller
than the hydraulic diameter, preferably smaller than half the
hydraulic diameter.
It is the purpose of the hollow space 16 to keep a defined
cross-sectional area of the proportioning disk 14 free for the
passage of gas. The surface area of the proportioning disk 14
exposed to the fuel is coordinated to its gas permeability in such
a way that a desired amount of gas is allowed to pass through in
the direction of the burner tip. The depth of the hollow space must
be at least of such a magnitude that the bracing force imparted by
the bracing disk 15 to the proportioning disk 14 and the non-woven
fiber material layer 13 does not impair the gas permeability of the
non-woven fiber material layer 13 parallel to the contact surface.
When the proportioning disk 14 has a thickness of 15 to 50 .mu.m
and the non-woven fiber material layer 13 has a thickness of 20 to
50 .mu.m, a depth of the hollow space 16, of, for example, 0.1 to
0.14 mm is sufficient. Due to its small thickness, the
proportioning disk 14 is extremely flexible, so that it yields into
an open space as a result of even a low pressure, as it can be
transmitted, for example, by the non-woven fabric material layer 13
without significant compression or as it prevails, for example, as
the saturated vaporization pressure in the tank 1. By the bracing
force exerted by the bracing disk 15, the non-woven fiber material
layer 13 is compressed in the region of the bracing surface and the
proportioning disk 14 is pressed into it, so that the bracing area
becomes gas-impermeable. In the region of the hollow space 16, the
non-woven fiber material layer 13 remains uncompressed. Due to the
flexibility of the proportioning disk 14 it is immaterial whether
the hollow space 16 is located on the side of the proportioning
disk 14 facing the tank or facing away from the tank, because, in
either case, a yielding into the hollow space 16 is possible
without substantial compression of the non-woven fiber material
layer 13. In this manner, a surface area corresponding to the
cross-sectional area of the hollow space 16 is reliably made
available for the passage of the gas, the only requirement being
that the non-woven fiber material layer 13 or another layer having
an equivalent effect is arranged at least in the region of the
hollow space 16 and is located on the side of the proportioning
disk 14 facing away from the tank 1.
The proportioning disk 14 and the gas-permeable non-woven fiber
material layer 13 are preferably situated in or immediately below
the plane of the tank ceiling 20.
For example, in a practical application of the invention, the
bracing disk 15 may have a diameter of 3 mm and the hollow space 16
may have a diameter of 1.8 mm and a depth of 0.12 mm in order to
achieve a flame height of 25 mm (normal flame) at 298.degree. K.
ambient temperature, in which case about 1 milligram of fuel is
consumed per second. By changing the cross-sectional area of the
hollow space, the flame height can be influenced directly.
In accordance with the invention, a quiet and uniform burning of
the flame in the normal, vertical position of operation is achieved
by an arrangement of the control device which as much as possible
reduces or excludes a direct contact of the proportioning disk 14
with the liquid phase of the tank filling. When the lighter is
moved from an undefined, for example, horizontal carrying position
into a vertical position for ignition, the liquid fuel, with the
exception of a residual amount retained by surface forces, flows
from the space situated in front of the proportioning disk 14 into
the tank 1, so that the proportioning disk 14 is exposed to gaseous
fuel and is separated from the liquid level 21 of the fuel.
Since the thickness of the bracing disk 15 is not greater than the
hydraulic diameter of the hollow space 16, the volume of the space
situated in front of the proportioning disk 14 is small. Since,
also due to the low surface tension and viscosity of the liquid
phase of the fuel, the flow resistance is low during flow-off, any
possibly retained residual amount of the fuel, relative to the
cross-sectional area of the proportioning disk available for the
passage of gas, is so small that it runs off, evaporates or burns
in a short time, for example, about 1 second. If any spontaneous,
bubble-forming boiling of the liquid fuel occurs at all on the side
of the proportioning disk 14 facing the tank 1, the amount
available for the boiling is evaporated after a short time.
Therefore, except for a very short start-up time, gas passes
through the proportioning disk 14 exclusively from the gaseous
phase of the fuel, so that a quietly and uniformly burning flame is
obtained.
The effect achieved in accordance with the invention can be
improved in a simple manner by various measures.
An improvement of the flow-off of the liquid phase as complete as
possible during moving the burner into the vertical position is
achieved by making the surface of the bracing disk 15 non-wettable.
This can be achieved, for example, by coating it with fluorinated
hydrocarbon compounds, for example, polytetrafluoroethylene.
When the bracing disk 15 is fuel-repellent, it is advantageous to
have a diameter of the opening 17 of such a small size that
capillary forces promote the flow-off of the fuel from the hollow
space 16.
If the bracing disk 15 has a wettable surface, the effect in
accordance with the invention can be improved by geometrically
constructing the opening 17 in such a way that capillary effects
are avoided.
Furthermore, the flame can be stabilized after ignition especially
quickly when the valve member 2 projects into the liquid-gas tank
in such a way that the size of the projection corresponds
approximately to the depth of the recess 12, so that the
proportioning disk 14 is located approximately in the plane of the
liquid-gas tank ceiling 20 of the liquid-gas tank 1.
While, in accordance with the invention, the intended effect is
achieved by a proportioning from the gas phase, the known solutions
attempt to obtain a wetting of the porous membrane with the liquid
phase which is as complete as possible. In these cases, due to the
thermodynamic conditions, a boiling with a spontaneous or periodic
bubble formation cannot be avoided, even if, in accordance with the
proposal of French Pat. No. 2,313,639, the bracing member is
constructed so as to be thermally insulating.
Further advantageous embodiments of the invention are explained
with the aid of FIGS. 2-8, each illustrating a cross-sectional view
of the control device. All reference numerals are selected in
accordance with FIG. 1.
FIG. 2 shows an embodiment wherein the hollow space 16 is formed by
a recess at the end face of the recess 12. Accordingly, the hollow
space 16 can be manufactured in one step with the production of the
recesses 12 in the valve member 2, which can be done with high
accuracy.
The illustrated construction of the bracing disk 15 results in a
symmetrical deformation of the proportioning disk 15 and of the
non-woven fiber material 13.
In FIG. 3, as in FIG. 2, the hollow space 16 is arranged on that
side of the proportioning disk 14 which faces away from the tank 1,
however, is limited at the periphery by a spacer ring 18 which, as
is true for the proportioning disk 14 and the non-woven fiber
material layer 13, is braced in a gas-tight manner by the bracing
disk 15. The spacer ring 18 consists of a plastics material of high
stiffness, compressive strength, dimensional stability under heat,
and low thermal conductivity. Particularly suitable for this
purpose are structural components of polyimide, for example, a type
manufactured by Du Pont under the tradename "Kapton.RTM.". This
material has approximately the same thermal expansion as brass, so
that, when the valve member 2 is made of machining brass, no
thermal tensions impair the function of the device in accordance
with the invention. The spacer ring 18 can be easily stamped from
commercially available films, which facilitates a very inexpensive
production. Moreover, the plastics material of the spacer ring 18
promotes the sealing action at the bracing surface. The opening 17
is small in relation to the hydraulic diameter, so that the
retention of large amounts of liquid fuel is avoided when the
lighter is moved into the vertical position.
The embodiment in accordance with FIG. 4 corresponds essentially to
that of FIG. 2, however, an intermediate ring 19 is arranged
between proportioning disk 14 and bracing disk 15. The intermediate
ring 19 consists of a plastics material of the type as it is also
advantageously used for the spacer ring 18, FIG. 3. As a result,
the sealing action of the bracing surface is promoted, on the one
hand, and, on the other hand, damage to the proportioning disk 14
during assembly is avoided when, for example, a measuring pipe is
attached for checking the amount of gas passing through.
FIG. 5 shows an embodiment in which a non-woven fiber material
layer 13 is arranged only in the region of hollow space 16 provided
in the valve member 2. For ensuring a good sealing action at the
bracing surface, and for avoiding damage to the proportioning disk
14 during assumbly, an intermediate ring 19 is arranged between the
bracing disk 15 and proportioning disk 14, as in FIG. 4. The
arrangement of the non-woven fiber material layer 13 exclusively in
the region of the hollow space 16 does not lead to functional
disadvantages, however, makes possible savings in material and
permits an especially simple assembly.
In FIG. 6, an embodiment is illustrated wherein the hollow space 16
is provided in the bracing disk 15 and continues into the opening
17 without projection. The purpose of this construction is to avoid
capillary effects in the case of a wettable surface of the bracing
disk 15. The opening 17 has a relatively large diameter, which
promotes the flow-off of the liquid phase in the case of a wettable
surface of the bracing disk 15, because a capillary effect is
avoided. Basically, the opening 17 toward the tank 1 can also be
constructed so as to widen in a funnel-shaped manner.
In FIG. 7, as in FIG. 6, the hollow space 16 is also arranged on
that side of the proportioning disk 14 which faces the tank 1,
however, as in FIG. 3, is formed by a spacer ring 18. The
properties of the spacer ring 18 have been explained in the
description of FIG. 3. This embodiment facilitates a very
economical production.
FIG. 8 shows an embodiment which essentially corresponds to that of
FIG. 1, however, an intermediate layer 19' is provided at the side
of the non-woven fiber material layer 13 facing the burner tip. The
intermediate layer 19' consists of a plastics material as it is
advantageously used for the spacer ring 18 for the embodiment of
the invention according to FIG. 3.
The manufacturing costs of the lighter according to the invention
are substantially reduced just by the fact that no large structural
components are required which would lead to high costs for
materials. Also, the costs for the mechanical finishing of the
structural components are low because it is not necessary to remove
large amounts of material and no work with exacting requirements
must be performed at locations which are not easily accessible, for
example, in deep blind-end bores.
Since the required small parts are all arranged in very shallow
recesses, the mounting of these parts is also free of problems and
can be performed withrelatively simple devices.
Moreover, the small dimensions of the structural components prevent
the occurrence of great thermal expansions or thermal tensions
which, for example, due to long-term storage or transport at high
temperatures, irreversibly reduce the necessary bracing forces.
The usually occurring dimensional deviations may lead to
substantial differences in the flame height within one production
series can be substantially reduced in an economical manner by the
device in accordance with the invention. On the one hand, the
simplicity of the required structural components facilitates a high
constancy in quality. The arrangement of all small parts in easily
accessible, shallow recesses also reduced the probability of
incorrect assembly. Moreover, it makes possible a check of the gas
permeability of the proportioning disk 14 in a simple manner, as
well as a conpensation of the observed inconsistencies of the
amounts of gas passing through. This can be done, for example, in
the following manner.
After inserting the non-woven fiber material layer 13 and the
proportioning disk 14 into the recess 12, a measuring pipe is
pressed on tightly. The measuring pipe has an exactly defined
internal diameter, preferably greater than the hydraulic diameter.
The amount of gas flowing through is measured and compared to a
fixed reference value. In the case of deviations caused by
inconsistencies of the permeability of the proportioning disk 14,
either the proportioning disk 14 can be blown out and be replaced
by a new one, or the diameter of the hollow space 16 is adjusted
accordingly. This can be done, for example, by selecting and
mounting a suitable combination of stored components with various
diameters of the hollow space, and of bracing disks 15 or spacer
rings 18. Such a checking and selecting device can be easily
included in a conventional automated manufacturing line.
In the known embodiment, measures for checking and compensating for
inconsistencies in the amounts flowing through are significantly
more complicated or cannot be carried out at all.
Another advantage of the device in accordance with the invention
concerns the change of the originally adjusted flame characteristic
due to aging which frequently occurs even without use of the
lighter. Using microporous, uniaxially stretched polypropylene
film, preferably of "Celgard.RTM.2500" as the material for the
proportioning disk 14, particularly in combination with a non-woven
fiber material layer 13 of non-woven propylene fibers, results in a
very high aging stability of the device in accordance with the
invention with respect to the constancy of the flame
characteristic.
The uniaxially stretched polypropylene film is deformable in the
non-stretched direction, so that the amount flowing through could
be influenced unintentionally. Therefore, it is advantageous to
construct the opening of the valve bore 11 in a very small size,
for example, 0.1 to 0.4 mm, so that the proportioning disk and the
fiber material layer cannot be pressed in by the gas pressure, and
it is also advantageous to limit the depth of the hollow space 16
.Iadd.between disk 14 and roof 24 .Iaddend.if the .[.latter.].
.Iadd.hollow space .Iaddend.is arranged on the side of the
proportioning disk facing the burner tip, .Iadd.as shown in FIG.
9.Iaddend., in order to avoid an irreversible deformation of the
proportioning disk under the influence of the gas pressure acting
on it.
Instead of the non-woven fiber material layer it is also possible
to use any other component which has a gas-permeable layer
alongside the contact surface with the proportioning disk 14. This
can be achieved, for example, also thereby that, as illustrated in
FIG. 10, the valve member 2 is roughened .Iadd.23 .Iaddend.on the
end face 2' of the blind hole-like recess 12 at least in the region
of the hollow space 16 in a suitable manner, for example, by means
of sand blasting.
In the production of lighters, such as, non-refillable pocket
lighters, the filling amount of the liquid gas must be limited to
approximately 80% of the volume of the fuel tank. During the
filling procedure, the ambient temperature is about 20.degree. to
25.degree. C. This limitation to 80% is necessary for safety
reasons because, during later storage or during the use of the
lighters, the liquid fuel may lead to an explosion-like bursting of
the tank in the case of substantially higher temperatures, such as
60.degree. C.
The fact that about 20% of the capacity of the tank must be
occupied by the gaseous phase of the fuel is utilized in the
lighters in accordance with the invention in order to ensure that
the proportioning disk and the components serving to brace the
proportioning disk do not come into contact with the liquid level
of the fuel when the lighter is used in the vertical position.
* * * * *