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Патент USA US3027942

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April 3, 1962
3,027,932
G. HUBER
BURNER HAVING A THERMOELECTRIC SAFETY DEVICE
Filed Feb. 25, 1960
78
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32 mum £91721,
United States Patent 0
_
3,027,932?
Patented Apr. 3, 1962
2
1
3,027,932
_
BURNER HAVING A THERMOELECTRIC
SAFETY DEVICE
Georg Huber, Starnberg, Upper Bavaria, Germany, as
signor to Wilhelm Baler K.G., Stockdorf, near Munich,
Germany
Filed Feb. 25, 1960, Ser. No. 11,043
Claims priority, application Germany, Feb. 27, 1959
3 Claims. (Cl. 158-28)
essentially in the provision of a burner including a ther
moelectric safety device which comprises a valve in
stalled in the supply conduit that conveys fuel to the
‘nozzle means of the burner, and a thermoelectric gen
erator or thermocouple whose hot junction is exposed
to the action of ?ames produced upon ignition of fuel
discharged by the nozzle means. An important feature
of the invention resides in the provision of shielding
means for the cold junction of the thermocouple which
10 is adapted to direct combustion air to the cold junction
and to thereby reduce the temperature of the cold junc
The present invention relates to fuel burners in gen
tion
even if the latter is located in very close proximity
eral, and more particularly to a pressure vaporizer burn
of the hot junction and of the ?ames. The shielding
er which comprises an improved thermoelectric safety
means preferably assumes the form of a tubular body
device adapted to shut off the supply of fuel when the
?ame is extinguished and to permit return ?ow of fuel 15 which surrounds the cold junction and which is located
in the path of combustion air so that the air may enter
at a given maximum pressure in the vaporizer chamber.
through the intake end and is discharged through at
It is already known to utilize thermoelectric safety
least one opening of the shielding means at a point ad
devices in liquid or gaseous fuel burners. However,
many presently known safety devices of such character
jacent to the cold junction. The thermocurrent generated
and weight of the arrangement and, therefore, such de—
to the nozzle means when it receives a thermocurrent
are rather expensive in that they must be operated by an 20 when the hot junction is exposed to the action of ?ames
is conducted to the aforementioned valve which is con
auxiliary burner which is commonly utilized as an igni
structed in such a way that it permits the flow of fuel
tion or pilot burner. The latter adds to the bulkiness
of given strength but automatically shuts off the sup
tain other types of known safety devices for fuel burners 25 ply ,of fuel when the strength of thermocurrent drops
below a given magnitude.
already comprise thermocouples which are exposed to
Certain other advantageous features of the invention
the ?ame produced by the main burner. However, all
reside in the provision of ?ame guiding means ‘for direct
such safety devices are extremely sensitive to vibrations,
ing additional heat to the hot junction of the thermo
and consequently, their life expectancy is too short for
vices have met with little success in actual use.
Cer
use in many types of burners. In addition, many safety 30 couple,‘ in the speci?c con?guration and dimensioning of
the shielding ‘means, in the provision of means for adapt
devices of presently known design must utilize two or
more thermocouples.
An important object of the present invention is to pro
ing the burner‘to operation with highly or less readily
.vaporizable liquid fuels such as petrol ‘and fuel oil, respec
tively, and in such ‘construction of the valve that it per
vide a fuel burner comprising. a thermoelectric safety de
vice which does not require a separate burner and which 35 mits return ?ow of fuel when the pressure at its discharge
side reaches a predetermined magnitude.
is less sensitive to vibrations or shaking.
The novel features which are considered as character
Another important object of the invention is to pro- ’
istic for the invention are set forth in particular in the
vide a fuel burner comprising a lightweight thermoelec
tric safety device of the just described characteristics
which is inexpensive to manufacture, which maybe
readily installed in many types of known liquid’burners,
which is of rugged construction and has a long life ex
pectancy without requiring frequent maintenance or in
spection, and which is of ‘very compact design in that it
appended claims. The invention itself, however, both as
40 to its construction and its method of operation, together
with additional objects and advantages thereof, will be
best understood from the following detailed description
of two speci?c embodiments when read in connection
with the accompanying drawing, in which:
comprises only one thermocouple with two junctions 45 l FIG. 1 is a vertical section through the burner com
bined with a thermoelectric safety device embodying one
which may be placed close to each other to produce a
form of my invention, the section being taken along the
strong .thermocurrent.
line I—-I of FIG. 2, as seen in the direction of arrows;
A further object of the invention is to provide a fuel
FIG. 2 is a section taken along the line II—-II of FIG.
burner comprising a thermoelectric safety device whose
thermocouple may be placed much closer to the main 50 1, as seen in the direction of arrows;
FIG. 3 is a greatly enlarged view of a magnet valve
?ame than the thermocouples of presently known safety
for the burner of FIGS. 1 and 2, the magnet valve being
devices whereby a single thermocouple can produce a
combined with a slightly modi?ed safety device and cer
current of such strength as is necessary to operate the
tain parts of the safety device and of the valve being
safety device.
An additional object of the invention is to provide a 55 broken away;
FIG. 4 is a transverse section taken along the line
liquid fuel burner comprising a thermoelectric safety
IV—IV
of FIG. 3, as seen in the direction of arrows; and
device which may be utilized in burners operating with
FIG. 5 is a greatly enlarged longitudinal central section
readily vaporizable as well as with hard-to-vaporize
of the thermocouple forming part of the safety device,
fuels.
the section being taken along the line V-—V of FIG. 3,
60
A concomitant object of the instant invention is to
as seen in the direction of arrows.
provide a burner embodying a thermoelectric safety de
Referring now in greater detail to the drawing, and
vice of the above outlined characteristics which is con
?rst to FIGS. 1 and 2, the injection nozzles 1, 1‘ of the
structed in such a way that it may control the radiation
pressure vaporizer burner B are supplied with a suitable
of heat to the thermocouple and which may be readily
65 liquid fuel through a supply conduit 2 whose intake end
adapted for use wtih different types of fuel.
is connected to a fuel source, not shown. The conduit 2
Still another object of the invention is to provide a
conveys fuel to a magnet valve 3 whose discharge port
is connected with a further conduit or vaporizer con~
burner provided with a thermoelectric safety device of
necting pipe 4 adapted to lead the fuel to an annular
the above described type wherein the safety device may
simultaneously control the delivery of fuel to two or more 70 vaporizer chamber 5. The latter is connected with the
nozzles 1, 1’ through a vaporizer pressure conduit 6.
The magnet valve 3 is shown in greater detail in FIG. 3.
With the above objects in view, the invention resides
nozzles.
'
>
3,027,932
3
4
It comprises a hand-operated pushbutton or actuating
13 which is comparatively cold and which is received in
a casing 33. Because the connecting wire 34 between
means 7 which is connected to a discoid valve member or
seal 26, the latter being normally urged into sealing posi
tion against its seat 27 by a helical expansion spring 28.
The coaxial stem 7a of the pushbutton 7 carries at its free
end an armature plate 30 which, upon depression .of the
member 7, moves toward the energizable magnet 36 sur
the junctions 12' and 13 is of constantan which is a ma
terial with very high resistance to the ?ow of electric cur
rent, the two junctions necessarily must be located rather
close to each other, i.e. so close that a heating of junc
tion 13 normally cannot be avoided when the junction
rounded by the coil 29, the latter being mounted in the
12' is heated, i.e. the junction 13 cannot be placed en
housing of magnet valve 3. Upon depression of the
tirely outside of the radius of action of the ?ame pro
pushbutton and consequent movement of valve member 10 duced upon ignition of vapors discharged by the nozzle
26 away from its seat 27, the fuel is free to pass from the
means. In accordance with my invention, undesirable
conduit 2, through the housing of valve 3, and into the
heating of thermocouple 12, i.e. of the junction 13 and its
conduit 4 to advance into the vaporizer chamber 5. The
casing 33 is avoided by the provision of protecting or
fuel advancing into, say, the nozzle 1 is discharged in the
shielding means which assumes the shape of a tubular
form of a thin stream onto the bottom 8 of the burner 15 body 14 (see FIG. 2) and which is mounted on the the'r-_
casing 9. The bottom ‘8, the upwardly extending end
mocouple 12 with the help of a nut v15 whose internal
plate 10, and the inclined feed plate 11 beneath the
threads mesh with external threads 35 on the casing 33
nozzles 1, 1' form a shallow pan-shaped receptacle for
(see FIG. 5). The front end‘ portion 14' of tube 14
the fuel discharged by the nozzles 1, 1’. This receptacle
which is adjacent to the nut or sealing means '15 is formed
is shown in FIG. 1. When su?icient fuel accumulates at 20 with one but preferably more axially parallel radially ar=
the bottom of the burner B, the pushbutton 7 is released
ranged openings or‘ slots ‘16 for discharge of combustion
and the resilient means ‘28 immediately returns the valve
air which on account of the draft effect ?ows through the
member 26 into sealing position, i.e. back into abutment
screen 23 in the direction of arrow A (see FIG. 2'), i.e.
with its seat 27. The fuel in the receptacle 8, 10, 11 is
in the axial direction and into the open rear end of shield
thenignited and heats the charged vaporizer chamber 5 25 ing means 14. In this manner, the cold junction 13 is al=
sufficiently to raise the pressure of fuel therein to the so
ways exposed to the cooling action of in?owin'g combus=
called working pressure. Such working pressure is
tion air, while the hot junction 12' is not in?uencedvby'
reached when the nozzles vbegin to discharge vapors; such
the in?owing combustion air. Consequently, the di?erl
vapors are immediately ignited by the fuel burning in the
ence in temperature of the junctions 12', .13 is. su?icient
aforementioned receptacle whereupon the ignited fuel 30 to generate. an electric current which is capable of enerl
vapors heat the chamber 5 without it being necessary to
gizing the magnet 36. The shielding tube 14 partially
renew the. supply of fuel abovev the bottom 8. Thus, the
surrounds the thermocouple 12, and the nut 15 consti-v
initial introduction of liquid fuel through one or both
nozzles is necessary merely to heat the chamber 5 suffi
ciently in order to begin the. vaporization of fuel; subse
quent'vaporization occurs automatically under the action
of ?ames produced upon ignition of vapors discharged
by the nozzles.
The control device for theburner B_, in addition to the
tutes a front end wall therefor which is perpendicular to
the tube axis. The rear end of the tube is open to permit
35 entry of combustion air.
It has been found that the length of tube 14 should be
at least 2 cm., preferably at least 3 cm. Tubes of a length
between 4.5-5 cm. have been found to be particularly
suitable for properly shielding and cooling the junction
above described magnet valve 3, comprises ‘a thermo
13. The diameter of the tube 14 is preferably selected
couple or thermoelectric generator 12 which is shown in
in such a way that its ratio to the length is about 1:2 but
FIG. 2 and is located adjacent to the chamber 5. This
preferably somewhat greater. The distance between the
thermocouple is now suf?ciently heated to produce a
sealing means 15 and the hot junction 12’ preferably ex“
ceeds 3 cm. ’
thermoelectric current of such magnitude as to supply
thenmocurrent to the magnet coil 29 which energizes the 45
The provision of shielding tube 14 renders it possible
magnet 36 in the housing of magnet valve 3 so that the
to place the hot junction 12’ of thermocouple 12 much
energized magnet 36 may retain the armature plate 30
closer to the flame, at least by 2 em. but preferably by
when the pushbutton 7 is depressed for a second time.
between 3-4 cm. closer than in heretofore known burners‘.
As is shown in FIG. 3 in connection with a slightly modi
As a result, the burner may utilize all types of fuel, i.e.
?ed thermocouple 12A, and also in FIG. 5, the thermo 50 a very volatile fuel (petrol) as well as a fuel which is
couple is electrically connected with the coil 29 by insu
di?icult to vaporize (fuel oil).
lated conductor ‘means 32in a tubular member or sheath
The improved burner further comprises a slidable
31.
'
?ame guiding pipe 17 (FIGS. 1 and 2) which is shifted
If the ?ame is extinguished for one reason or another,
into the center of vaporizer chamber 5 when the device
e.g. owing to blocking of a nozzle, the thermocouple 12 55 is converted for operation with fuel oil. The tubular
is cooled and the magnet 36 is progressively deenergized
member 17 is suspended on the straight portion of the
whereby, in response to a certain temperature of the
vaporizer pressure conduit -6 by means of an element 18
which latter is combined with an elongated bar or guide
rod 19 adapted to slide along the upper wall of the
thermocouple 12, the spring 28 disengages the armature
plate- 30 from the magnet 36 and returns the valve mem
ber 26 into sealing position. The supply of fuel to the 60 vaporizer chamber 5 and to thereby guide the pipe 17 in
vaporizer chamber 5 is now interrupted.
movements into and out of said chamber. The pipe 17
If, during warming up of the vaporizer chamber, a
is formed with a radial opening 20 which is adjacent to
person not familiar with the operating instructions would
the hot junction 12' when the member 17 is in the posi
turn the adjusting wheels 24, 25 into such position as to
tion
of FIGS. 1 and 2, i.e. located externally of the cham
close the nozzles 1 and 1', excess pressure will build up 65
ber 5. Thus, when the burner is operated with petrol,
in the vaporizer chamber. In accordance with one fea
the hot junction 12' of thermocouple or thermoelectric
ture of the present invention, the magnet valve 3 is con
generator 12 is also affected by heat radiated by ?ames
structed in such a way that the excess pressure of fuel in
in the pipe 17. It is preferred to provide an inclined
vaporizer chamber 5 automatically lifts the valve mem
ber 26 off its seat 27 whereby the fuel may ?ow back 70 de?ecting device or baffle 21 in the open front end of the
through the valve 3, thus eliminating the danger of an
pipe 17 which directs heat toward the hot junction 12’ at
explosion due to improper operation of the burner B.
the forward end of the thermocouple. The main purpose
As is best shown in FIG. 5, the thermocouple 12 or
of the pipe 17 is to guide the concentrated ?ames against
12A comprises a ?rst or hot junction 12' which is heated
the inner wall of chamber 5 to thereby assist in more
during the operation of the burner, and a second junction 75 rapid vaporization of fuel oil.
3,027,932
5
As is shown in FIGS. 1 and 2, a cover or lid 22. may
be pivoted to the casing 9; this cover is provided with a
large intake opening for combustion air which prefer
ably contains a screen 23 of wire netting or the like.
When the ?ame guiding tube 17 is moved to the right,
as viewed in FIG. 1 or 2, i.e. into the vaporizing cham
ber 5, the ?ames may pass from the nozzle or nozzles 1,
.
6
of fuel to said chamber when receiving a thermocurrent
of given strength and automatically shutting off the ?ow
of fuel when the strength of thermocurrent drops below
the given value, a thermocouple connected with said valve
means, said thermocouple having a hot junction located
adjacent to and adapted to be heated by the portion of
?ames de?ected through the opening of said ?ame guid
ing means and a cold junction, and shielding means lo
cated in the path of combustion air for the ?ames and
channel de?ned by the outer side of the chamber 5 and
the wall 9. This is desirable when the chamber 5 is to 10 adapted to direct combustion air against said cold junc
tion whereby the latter may be placed in immediate
be heated to a higher temperature, namely, when the fuel
proximity of the ?ames and the thermocouple still pro
is less ‘volatile, e.g. an oil. On the other hand, when the
duce a thermocurrent of such strength as is necessary to
fuel is more volatile, e.g. when the fuel is petrol, the
maintain the valve in fuel ?ow permitting position.
?ame guiding tube may be moved to the left, as viewed
2. In a fuel burner, in combination, nozzle means;
in FIGS. 1 and 2, whereby the ?ames are confined to 15
conduit means for supplying fuel to said nozzle means;
flow through the pipe 17 and heat only the interior of
an annular vaporizer chamber in said conduit means dis
the chamber 5.
posed
in such proximity of said nozzle means as to be
When the tube 17 is moved to the right and into the
heated by ?ames produced upon ignition of fuel dis
chamber 5, the ?ames are free to heat the hot junction
12’ because the propagation of ?ames from the nozzle 20 charged by the nozzle means; tubular ?ame guiding means
provided between said nozzle means and said vaporizer
or nozzles 1, 1' to the inner and outer sides of the cham
chamber for directing ?ames into the interior of said
ber 5 is unobstructed. On the other hand, when the tube
chamber, said ?ame guiding means having at least one
17 is moved to the left so that it con?nes the ?ames to a
radial opening through which a portion of the ?ames
?ow only to the interior of the chamber 5, the ?ames de
?ected by the ba?’le 21 through the opening 20 will heat 25 may be de?ected from the direction of ?ame propagation
to said chamber, and said ?ame guiding means further
the hot junction 12’ to produce the necessary thermo
comprising baffle means located forwardly of said open
current.
ing for de?ecting the ?ames in said ?ame guiding means;
The provision of the opening 20 in the tube 17 renders
and a thermoelectric safety device for controlling the
it possible to mount the thermocouple 12 in close proxim_
ity of the vaporizer chamber 5 without the danger of 30 ?ow of fuel to said chamber and to said nozzle means,
1’ inwardly of the chamber 5 as well as into the annular
overheating the thermocouple. Furthermore, such posi
tioning of the thermocouple facilitates the starting of the
said device comprising valve means in said conduit means
the passages 40, 41. The front end face ‘38’ of the end
3. In a fuel burner, in combination, nozzle means; con
duit means for supplying fuel to said nozzle means; a
adapted to permit the ?ow of fuel to said chamber when
receiving a thermocurrent of given strength and auto
burner B because the thermocouple responds more rapid
matically shutting off the ?ow of fuel when the strength
ly, and the position of the thermocouple need not be
changed when the fuel is changed, i.e. when it is desired 35 of thermocurrent drops below the given value, a thermo
couple connected with said valve means, said thermo
to switch from oil burning to a burning with pertol. All
couple having a hot junction located adjacent to and
that is necessary is to shift the tube 17, whereas the posi
adapted to be heated by the portion of ?ames de?ected
tion of the thermocouple 12 remains unchanged.
through the opening of said ?ame guiding means and
FIGS. 3 and 4 show a slightly modified thermocouple
112A comprising a shielding tube 37 whose front end 40 a cold junction, and shielding means located in the path
of combustion air for the ?ames and adapted to direct
portion is ?attened, as at 38, and is welded to the nut 15
combustion air against said cold junction whereby the
which latter is centrally received in said end portion. In
latter may be placed in immediate proximity of the ?ames
this manner, the end portion 318 de?nes two passages or
and the thermocouple still produce a thermocurrent of
channels 40, 41 at the opposing sides of retaining nut
1'5, the combustion air entering through the open rear 45 such strength as is necessary to maintain the valve in fuel
?ow permitting position.
or intake end 39 of tube 37 and being discharged through
portion 38 is preferably ?ush with the exposed side of
vaporizer chamber in said conduit means disposed in such
Without further analysis, the foregoing will so fully 50 proximity of said nozzle means as to be heated by ?ames
produced upon ignition of fuel discharged by the nozzle
reveal the gist of the present invention that others can,
means; ?ame guiding means movable between said nozzle
by applying current knowledge, readily adapt it for vari
means and said vaporizer chamber for directing ?ames
ous applications without omitting features that, from
into the interior of said chamber when moved toward said
the standpoint of prior art, fairly constitute essential
characteristics of the generic and speci?c aspects of this 55 nozzle means and for permitting the ?ames to heat the
exterior of said chamber when moved toward and into the
invention and, therefore, such adaptations should and
chamber, said ?ame guiding means having at least one
are intended to be comprehended within the meaning and
opening through which a portion of the ?ames may be
range of equivalence of the following claims.
de?ected from the direction of ?ame propagation to said
What is claimed as new and desired to be secured by
60 chamber; and a thermoelectric safety device for con
Letters Patent is:
trolling the flow of fuel to said chamber and to said nozzle
1. In a fuel burner, in combination, nozzle means;
nut 15.
conduit means for supplying fuel to said nozzle means; a
means, said device comprising valve means in said con
duit means adapted to permit the ?ow of fuel to said
chamber when receiving a thermocurrent of given strength
?ames produced upon ignition of fuel discharged by the 65 and automatically shutting off the ?ow of fuel when the
strength of thermocurrent drops below the given value, a
nozzle means; ?ame guiding means provided between
thermocouple connected with said valve means, said
said nozzle means and said vaporizer chamber for direct
thermocouple having a hot junction located adjacent to
ing ?ames to said chamber, said ?ame guiding means hav
ing at least one opening through which a portion of the 70 and adapted to be heated by the portion of ?ames de
?ected through the opening of said ?ame guiding means
?ames may be de?ected from the direction of ?ame
when the latter is moved toward said nozzle means and
propagation to said chamber; and a thermoelectric safety
a cold junction, said hot junction heated by the ?ames
device for controlling the ?ow of fuel to said chamber
heating the exterior of said chamber when the ?ame guid
and to said nozzle means, said device comprising valve
means in said conduit means adapted to permit the ?ow 75 ing means is moved into the chamber, and shielding means
vaporizer chamber in said conduit means disposed in
such proximity of said nozzle means as to be heated by
3,027,932
7
8
located in the path of combustion air for the ?ames and
adapted to direct combustion air against said cold junction
whereby the latter may ‘be placed in immediate proximity
of the ?ames
and the thermocouple
still produce a‘t’
ther
tf‘ht
thi‘
mocurren o suc s reng
as 1s necessary to mam am
the val
' f l?
'tt'
o to .
V6 1“ ue
ow Perm‘ mg P S“ “
References Cited in the ?le of this patent
UNITED STATES PATENTS
5
J
2,303,807
2,322,410
gflggféarfner
16 ------------------------- ----Algll‘éyzg’,
Wilson _______________ __ Dec. 1, 1942
Alfery ______________ __ June 22, 1943
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