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Патент USA US3051867

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Aug. 28, 1962
J. M. HOFF
3,051,862
GAS IGNITOR
Filed Feb. 10, 1960
FIG. 1
('°
GAS
BURNER
2’
Ki
W
L3
193
INVENTOR.
JOHN M.
@Mn,
HOFF
5W
ATTORNEYS
United States Patent Office
1
3,051,862
John M. Ho?, Mans?eld, Ohio, assignor to The Tappan
GAS IGNITOR
3,051,862
Patented Aug. 28, 1962
2
The wire electrode is bare and its turns 16 accordingly
spaced apart and non-contacting.
At its other end, which is within the housing 13, the
wire electrode 15 is bonded to a conductor 17 which pro
jects from the rear end of the housing. Excluding the
mouth 14, the space within the housing 13 and surround
ing the enclosed portions of the wire electrode 15 and
This invention relates to an improved electrode de
conductor 17 is ?lled with suitable thermal and electri
cal insulation 18. A ?ller of granular magnesium oxide
vice for electric spark ignition of combustible gases, such
as the gas-air mixtures used in domestic gas range burn 10 has ‘been used for the purpose, and the material is ?rm
1y packed in the housing for support of the inner elec
ers, associated pilot burners and the like.
It is a primary object of the invention to provide an
trode and connected conductor therewithin.
A terminal strip 19 is suitably bonded to the project—
ignitor of this class which will operate e?iciently at sub
stantially lower voltage and current values than has com
ing end of the conductor 17 and, as shown in FIG. 1,
monly ‘been thought necessary for the purpose, whereby 15 a wire connects this terminal to one side of the secondary
winding of a step-up transformer 20, while the other
the new ignitor is both more economical than convention
side of such secondary winding is connected by 'a wire to
al devices and safer in operation.
the housing or outer electrode. The primary of this
Another object is to provide such an ignitor having
transformer is adapted to be connected to a conventional
a very long service life, this characteristic resulting from
source of supply, and I have shown a simple switch 21
a special feature of construction which affords compen
in the supply circuit to the transformer for control of
sation for the electrode erosion and loss which inevitably
Company, Mans?eld, Ohio, a corporation of Ohio
Filed Feb. 10, 1960, Ser. No. 7,827
3 Claims. (Cl. 313-146)
occurs.
the ignitor. Basically, the operation involves applying,
‘Other objects and advantages of the present invention
by means of such transformer, high voltage at low cur
rent to the electrodes to create a spark therebetween ef
will ‘become apparent as the following description pro
25 fective to ignite the gas-air mixture supplied to the pilot
ceeds.
‘burner 11, with the raw gas issuing from such burner
To the accomplishment of the foregoing and related
being caused at least in part to flow over the mouth of
ends, the invention, then, comprises the features herein
the ignitor. The physical arrangement of the compo
after fully described and particularly pointed out in the
nents may vary, but it is desirable to locate the ignitor
claims, the following description and the annexed draw
ing setting forth in detail certain illustrative embodiments 30 so as to be in the stream of the raw gas to be ignited
and yet not in the ?ame produced. For example, a rela
of the invention, these being indicative, however, of but
tive positioning as shown will protect the ignitor from
a few of the various ways in which the principle of the
?ame damage by virtue of the normal updraft resulting
invention may be employed.
by combustion and corresponding direction of the ?ame.
In said annexed drawing:
For a number of reasons, it is signi?cant that the inner
FIG. 1 is a diagrammatic view of a gas burner assem 35
electrode of the new ignitor is in the form of a wire of
bly, such as found in a domestic gas range, including an
small cross-section; as a more speci?c example, this elec
electric ignitor in ‘accordance with the present invention;
trode has been made of nichrome wire of .032 inch diam
FIG. 2 is an axial cross-section of the ignitor on an
enlarged scale;
eter. Such dimensioning provides a highly concentrated
FIG. 3 is a similar section at right angles to the sec 40 spark and, since the wire electrode has such little mass, the
?ow of the gaseous mixture to the region of the spark is
tion shown in FIG. 2; and
practically unobstructed. Moreover, heat is not readily
FIG. 4 is an end view of the ignitor.
conducted away from the tip of the wire electrode, as
Referring now to the drawings in detail, the vgas burner
would be the case with a fairly heavy electrode, and such
10 shown diagrammatically in FIG. 1 is a conventional
oven burner of a domestic gas range having a series of 45 tip actually glows and promotes ignition on such account.
By virtue of these characteristics, it has been found that
ports along the bottom thereof for issue of the usual
the new ignitor will operate properly, as compared to con
combustible mixture of gas and air supplied to such a
ventional devices on the same order, at considerably re
burner. Beneath this oven burner, adjacent one end of
duced voltage and current values. For example, whereas
the same, there is a pilot burner 11 which is again of
conventional form and adapted to be supplied with the 50 an ordinary spark ignitor may require 5,000 volts at .013
ampere, an ignitor constructed as aforesaid and including
same gaseous mixture. An electric ignitor, designated
a wire electrode of the type and size speci?cally set forth
generally by reference numeral 12, is here associated
will function with a supply of 2,000 volts at .008 ampere.
with the pilot burner 11 for controlled ignition of the
The electrode gap in the new ignitor will generally be on
gas-air mixture issuing therefrom when the supply of the
mixture is established to the same, and the resulting pilot 55 the order of from .020 to .060 inch.
The end portion 15’ of the wire electrode will in time
?ame, of course, is used to ignite the main or oven
become shortened by inevitable loss of metal, and the turns
burner.
or coils 16 provide for lengthening the electrode to make
This ignitor comprises a tubular housing 13, which
up such loss. That is, the turns constitute, in effect, stor
has been made of stainless steel, with one end thereof
?ared to form a mouth 14 of conical section. As will 60 age of the wire and, when the gap has increased to a point
where loss of the spark cannot adequately be corrected by
appear more clearly below, the housing forms an outer
bending the initial exposed end length of the wire elec
electrode, and there is an inner electrode 15 in spaced re
trode, the wire is simply pulled from the insulative pack
lation within the housing. Such inner electrode is in the
ing to extend the end turn until the initial exposed length
form of a wire of small cross-section and high electrical
resistance extending generally along the axis of the hous 65 is re-established. The encircling nature of the outer elec
trode, of course, facilitates positioning of the tip of the
ing 13 and being coiled into a plurality of turns 16 in
wire electrode, and the relatively large area of the surface
the region of the housing just behind or .the rear of the
available for the spark also keeps this electrode “cool” as
mouth 14. The terminal portion 15’ of the wire elec
a result of conductive dissipation of heat therein at the
trode at this end of the ignitor projects into the mouth
14 and extends interiorly thereacross at a considerable an 70 region of the spark, with deterioration of this electrode
being negligible for practical purposes.
gle to the axis, with the extreme end or tip in close-spaced
opposition to the conical inner surface of the mouth.
As workers in the art will appreciate, a typical gas cook
3,051,862
ll
ing oven assembly in which the ignitor may be used will
include various controls of known design and function for
regulation, and possibly programming, of the oven opera
2. An electric spark ignitor for gaseous fuel burning
tails described, provided the features stated in any of the
following claims or the equivalent of such be employed.
I, therefore, particularly point out and distinctly claim as
3. An electric spark ignitor for gaseous fuel burning
devices, comprising a ?rst electrode made of wire of small
cross—section and high electrical resistance, a second elec
trode having a surface disposed in close spaced opposition
devices, comprising a ?rst electrode made of wire of small
cross-section and high electrical resistance, a second elec
trode having a surface encircling an end position of said
tion. While these are not necessary to the present inven
tion, it may be noted that the pilot burner will desira-biy
first electrode, the thus encircled end portion of the ?rst
incorporate a ?ame control of suitable type to prevent the
electrode being at a substantial angle to‘ said surface with
its tip in close spaced opposition thereto to form a spark
?ow of gas to the oven burner when the pilot is cold, or in
gap with the same, the ?rst electrode wire having a plural
other words, until after the pilot ?ame has been estab
lished by ignition. The ignitor energization should prefer
ity of storage turns therein for extension of the same to
ably be maintained for a de?nite interval to insure ignition, 10 compensate loss of material at such spark tip thereof, and
and the switch controlling the same can be of a type which
a compacted mass of particulate thermal insulation mate
rial surrounding such turns and the remote extent of the
will open only after a time delay for automatic provision
of this feature.
?rst electrode, the ?rst electrode including the turns thereof
Other modes of applying the principle of the invention
being thus embedded in said material and being extensible
may be employed, change being made as regards the de
from within the same.
my invention:
1. An electric spark ignitor for gaseous fuel burning 20 to an end of said wire to form a spark gap therewith, said
?rst electrode having a plurality of storage turns formed
devices, comprising an outer electrode in the form of a
tube having a ?ared mouth at one end, an inner electrode
therein and a terminal connection at its other end, the
in spaced relation within said outer electrode, said inner
turns providing for extension of the Wire electrode relative
electrode being made of wire of small cross-section and
to the terminal connection thereof to compensate for loss
of material at the spark gap end to maintain proper gap
dimension, and a compacted mass of particulate thermal
high electrical resistance, the inner Wire electrode having
an end portion within the mouth of the outer electrode at
a substantial angle to the wall of the same and with its tip
insulation material surrounding such turns and the remote
extent of the ?rst electrode.
in closed spaced opposition to the inner surface of said
wall, thereby to form a spark gap with the outer electrode,
References Cited in the ?le of this patent
UNITED STATES PATENTS
the wire inwardly with respect to the rnouth having a series
of spaced storage turns therein, and being connected at its
removed end to an external conductor, and a compacted
mass of particulate thermal and electrical insulation mate
rial ?lling the space within the outer electrode about said
turns and the extent of the wire electrode to the rear of 35
the same, the wire electrode including the turns thereof
being thus embedded in said material and being extensible
from within the same at the gap-forming end to compen
393,304
895,030
Haskins _____________ __ Nov. 20, 1888
Lang ________________ __ Aug. 4, 1908
1,290,121
Donat ________________ __ Jan. 7, 1919
2,241,295
2,548,300
Clark _______________ __ May 6, 1941
Garner _______________ __ Apr. 10, 1951
2,948,824
Smits ________________ __ Aug. 9, 1960
840,961
France _______________ __ Jan. 28, 1939
FOREIGN PATENTS
sate for consumption of said wire electrode in use of the
ignitor.
40
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