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Патент USA US3059090

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Oct. 16, 1962 l
FiledASepÍ.. 17, 1959
2 Sheets-Sheet l
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Uct. 16, 1962
Filed Sept. 17, 1959
2 Sheets-Sheet 2
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Patented Oct. 16, 1962
Leland B. Wagner, Goshen, Ind., assignor to Penn Con
trols, Inc., Goshen, ind., a corporation of Indiana
Filed Sept. 17, 1959, Ser. No. 840,666
5 Claims. (Cl. 2011-138)
This invention relates generally to combustion respon
sive devices and in particular to a flame detector adapted
for mounting within lche blast tube of a conventional oil
In conventional oil burner installations the combustion
responsive switch, lforming a part o-f the control for the
burner, is mounted at a location in the burner stack where
it can properly indicate the presence or absence of com
bustion. Since this location is relatively remote from
the burner llame itself, and because of the thermal inertia
ofthe oil ñred furnace’s heat exchange surfaces and stack,
the reaction time of such remotely mounted combustion
welded thereto a sidewardly extending, threaded member
11. Tihe threaded member is adapted to receive a nut
(not shown) an-d is inserted into a slot 12 in a bracket ‘13
which is spot welded to a ring clamp 14 as may be seen
in FIG. 7. The clamp 14 is adapted to encircle the
nozzle of an oil `burner within the oil burner blast tube,
the nozzle being shown schematically at 16 in FIG. 7.
rlightening of the bolt 18 serves to clamp the ring 14
about the oil burner nozzle and provides a mounting
means for the llame detector. By means of the elongated
slot 12, the flame detector may be varied in position along
the axis of the oil burner nozzle.
ri‘he housing l() is cup-shaped and its closed end 15,
disposed remotely from the burner llame, is provided
with three apertures bounded by outwardly extending
flanges 19. The apertures are filled with a fusible mate
rial such as glass indicated at 2l in FIG. 2, the fusible
material supporting terminal lugs 22. Slidably inserted
within the housing is a switch accommodating cartridge
responsive switches is prolonged. Further, since the 20 which includes a frame 23. Rearwardly extending tabs
24, formed integrally with the frame, are bent to secure
combustion responsive switch is mounted separately from
the frame to an end plate 26 formed of electrical insulat~
the burner at a location dictated by the particular installa
ing material. Extending from the rear face of the end
tion, this control cannot be pre-wired by the burner
plate 26 are resilient contact leaves 27 which engage the
The apparatus herein disclosed and claimed represents 25 inner ends of the terminals 22 and make electrical con
tact therewith. One of the leaves 27 is electrically con
an improved version of the flame detector disclosed and
nected to the plate 28, another is connected to a switch
claimed in my United States Patent 3,033,978, issued
contact 29‘ and the third is connected to a bracket 31
.lune 12, 1962 and titled “Flame Detector.”
'carrying a second switch contact 32. A movable contact
It is an object of the present invention to provide a
structure cooperates with the contacts 29 and 32 by means
flame detector switching device adapted Vfor mounting
of a slip-friction arrangement which is described in de
within the blast tube of an oil burner to directly view the
tail an-d claimed in my above-mentioned copending appli
burner llame and which utilizes the reflector member
»for directing heat to the bimetal temperature responsive
A further object of the present invention is to provide
a ñame detector switching device of the type referred
to which is sealed against the entry of soot or dirt but
which retains a relatively high degree of sensitivity to the
presence or absence 'of a burner flame.
In general, the movable contact structure includes a
plate 33 which extends between the contacts 29‘ and 32
and is carried by a bracket 34. The bracket 34 is aper
tured to freely receive the thrust element 36. The bracket
carries a leaf-type spring 37 whose free end frictionally
engages the thrust member 36. A screw 38 threaded into
Another object is to provide a llame detector wherein 40 the plate 28 serves to electrically attach one end of a
pig-tail lead wire 39 to the bracket '34.
a bimetal element has the transfer of heat to it by con
The open end of the cartridge provided by the frame 23
duction minimized and the transfer of heat to it by radia
is closed by a reiiector plate 41, the reflector plate butting
tion maximized.
against the marginal edge of the frame 23 as may be
An additional object is to provide a flame detector
wherein a bimetal element has the transfer of heat by 45 seen in FIG. 4. As may best be seen in FIG. 4, two
yannular members 42, which may -be formed of Teflon or
conduction from it to surrounding objects minimized.
similar material abut the plate 41 and have formed there~
Still another object is to provide a bimetal element in
in diametrically opposed notches y43 which have inclined
a flame detector which is supported by a mounting which
sidewalls. The adjacent notches in the members 42 thus
has a low thermal conductivity and has a minimum area
50 provide substantially V-shaped depressions. Seated in
in contact with the bimetal element.
the depressions are the ends of a bimetal element 44 which
The full nature of the invention will be understood
extends diametrically across the housing. Extending from
the inner face of the element 44 and freely through an
aperture 46 in the reflector plate 41 is the -thrust member
FIG. l is an end View of an assembly embodying the
55 '36, the thrust member being Welded to the bimetal element.
present invention.
from the accompanying drawings and the following de
scription and claims:
An annular hold-down ring 47 overlies the outermost one
FIG. 2 is a side elevational view of a switch accommo
of the annular members 42 and the assembly thereby
dating :cartridge of the assembly surrounded by a sec
formed is held in stacked relation by means of forwardly
tional view of its housing taken along the line 2_2 of
exten-ding tabs 48 which are formed integrally with the
FIG. l.
60 frame '23.
FIG. 3 is an end 4View of the assembly taken from the
'In assembling the apparatus the cartridge subassembly
end opposite that of FIG. l.
is inserted in the housing 10 and positioned so that the
FIG. 4 is a sectional view of a portion of the assembly
leaves 27 engage the terminals 22. The end of the housing
taken along the line 2_2 of FIGURE 1.
is then sealed by means of a stainless steel cup-shaped
FIG. 5 is a front view of the reflector plate.
65 element 49. The element 49 is provided with a black,
FIG. 6 is an end elevational view of a stainless steel
cup-shaped element used to enclose the opposite end of
the assembly.
non-reflecting finish on its outer face so as to absorb
radiant heat from the burner flame. The edge of the
sealing plate 49 is welded to the adjacent annular, margi
FIG. 7 is an end View of the attachment `for clam-ping
nal surface of the housing 10. As may best be seen in
the assembly to the nozzle of an oil burner..
70 FIG. 6, the plate 49 is provided with four diametrically
Referring initially to FIGS. 1 and 7, the flame detect
opposed raised portions 51 which accommodate the tabs
ing apparatus includes a cylindrical housing 10 having
Stiffening ribs 52 extend between the raised por
3,059, oso
tions 51 and provide the required rigidity for the rela
to receive radiant heat from a source thereof, said de
tively thin plate 49.
vice comprising a tubular housing having two closed ends
In operati-on, with the assembly clamped upon the noz
zle of an oil burner, the plate or element 49 will be
with one said end facing the heat source being con
structed of a thin metallic wall with a dull black outer
facing the burner llame and will receive radiant heat
therefrom. In turn, the bimetal element 44 will receive
heat both by radiation `and convection from the inner
face of the sealing plate 49. The resulting movement
in said housing, mounts constructed of a material having
a low thermal conductivity in said housing, a tempera
ture responsive Ibimetal element mounted diametrically
surface, spaced stationary switch contacts supported with
of the bimetal member in response to the presence or ab
sence or llame at the burner will serve to position the
contact plate 313 against one or the other of the fixed
across the said tube near said one end facing the heat
source by said mounts, a thrust member extending into
said housing from the inner face of said bimetal element
and adapted to be moved lineally as said element re
sponds to temperature change, a clutch arm slidably
mounted on said thrust member, resilient means acting
contacts 29 and 32. Because of the slip-friction connec
tion between the thrust member 36 and the bracket 34,
the contacts will be operated upon a predetermined change
in temperature as is Well known in the art. The opera 15 between said thrust member and said arm to resist move
tion Iof the switching elements is not described in detail
ment of said arm along said member, a contact element
herein but is described `in detail in my copending applica
carried by said arm and adapted to engage one or the
other of said stationary contacts depending upon the di
While the bimetal element 44 is sealed from direct
rection of motion of said thrust member, and a reflector
thermal radiation from the burner ñame by the plate 49,
mounted in said tubular housing to receive radiant heat
the sensitivity of response of the flame detector is main
energy from said one end facing the heat source and to
tained at the desired point because of the presence of the
focus said heat energy onto said bimetal element.
rellector plate 41. As may Ibe seen in FIGS. 4 and 5,
3. A sensitive heat detector comprising a heat respon
the reflector plate is of concavo-convex configuration,
sive element, a mounting composed at least in part of a
and its concave surface 41a is provided with a smooth,
non-metallic material having a low thermal conductivity
heat reflecting finish. The reñector plate serves to focas
and supporting said element with only a small area of
heat radiated from the inner face of the sealing plate
the non-metallic part in contact with said element to
49 on to the bimetal element 44, and the curvature of
minimize the transfer of heat by conduction between said
the plate tends to retain a pocket of heated air about
element .and `any surrounding objects, and a means for
the bimetal element. The ñame detector assembly just 30 concentrating infrared radiation onto said element to maX
described provides a structure which is sealed against
imize the transfer of heat by radiation to said element.
entry of soot or dirt into the switching elements. While
4. A lsensitive heat detector comprising a bimetal ele
the bimetal element 44 is `shielded from direct radiation
ment, a mounting composed at least in part of a non
from the burner iiame, the concave-convex reflector plate
metallic material having a low thermal conductivity and
41 serves to maintain the sensitivity and rapidity of re 35 supporting said «bimetal element with only a small area
sponse of the device.
of the non-metallic part in contact with the edges of
While the invention has been disclosed and described
said element to minimize the transfer of heat by conduc
in some detail in the drawings and foregoing description,
tion between said element and any surrounding objects,
they are to be considered as illustrative and not restrictive
and a reflector for concentrating infrared radiation onto
in character, as modifications may readily suggest them
said element `to maximize the transfer of heat by radia
selves to persons skilled in this art and within the broad
tion to said element.
scope of the invention, reference being had to the ap
5. A sensitive heat detector in accordance with claim 4
pended claims.
wherein said bimetal element is an elongated thin bimetal
The invention claimed is:
strip and the non-metallic part of said mounting has V
1. A heat detector control device comprising a hous- .
shaped notches receiving the ends of said element to
ing, a portion of said housing facing a source of heat be
establish a minimum contact area between said mounting
ing constructed of a thin metallic wall with a non-reflec
and said element.
tive outer surface, a reflector mounted in said housing,
mounting means constructed at least in part of a non
References Cited in the ñle of this patent
metallic material having a low thermal conductivity, a
bimetal element mounted in said housing and in contact
Yerrington __________ __ Apr. 28, 1903
with only the non-metallic part of said mounting means
to operate a control means as said bimetal element ex
pands and contracts, said reflector being positioned to re
ceive radiant heat energy from said portion of said hous
ing and to focus said heat energy onto said bimetal ele
2. A radiant heat detecting switching device adapted
CA ci
Apfel ______________ __ Aug. 22, 1922
Pendleton __________ __ Apr. 16, 1935
McCabe ____________ __ June 1‘3, 1939
Koci _______________ __ May 29, 1951
Moorhead ___________ __ Feb. 18, 1958
Ganske et al. ________ __ Nov. 24, 1959
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