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Патент USA US2076968

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April 139 1937.
B E SHAW
'
BURNER CONTROL SYSTEM
Filed Jan. 6, 1956
22x1‘
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'
i732,
2,@7?,963
2,076,968
I Patented Apr. 13, 1937
@FFICE.
UNITED
attests?
BURNER (CGNTRUL srs'rsM
Burton E. Shaw, Adel, liowa, assignor to Penn
Electric Switch Company, Des Moines, llowa, a
corporation of Iowa
Application January 6, 1936, Serial No. 57,’?‘3‘5
12 Claims. (Cl. 200-122)
An object of my invention is to provide a burner
control system which is inexpensive to manu
facture and simple in operation and arrangement
of parts.
_
A further object is to provide a controller in
cluding burner contacts and safetyswitch con
tacts, both operable from a single actuator, thus
eliminating a relay and to provide a combustion
temperature responsive means associated with
10 the controller for modifying the operation of the
burner and safety switches by the actuator.
A further object is to provide a heat responsive
insulation, is provided for mounting the various
elements of the controller. A tube l4 extends
from the rear of the casing it for extension into
a stack or other portion of a furnace, so that a
bimetal element it, carried by the inner end of
the tube l4, may respond to combustion tem
peratures.
The bimetal element i6 is U-shaped and an
chored at one end to a stationary lug iii, an arm
actuator for ?rst closing a normally open burner
switch and then opening a safety switch, com
15 bustion temperature actuated means being oper
able to arrest the movement of the actuator after
the burner switch is closed, provided combustion
is successfully established.
Another object is to provide a controller in
which a resistance or heating element effects
20 operation of a warp element or the like, a shield
being interposable between the two to prevent
operation of the actuator in accordance with
certain conditions.
A still further object is to provide a shield so
25 constructed that it re?ectsthe heat from the
heating element and absorbs heat from the actu
ator, the degree of absorption and re?ection being
predetermined, depending on requirements for
30 the various installations.
With these and other objects in view, my in
vention consists in the construction, arrangement
and combination of the various parts of the de
vice, whereby the objects contemplated are
35 attained, as hereinafter more fully set forth,
pointed out in my claims,—and illustrated in the
accompanying drawing, in which:
Figure 1 is a front elevation of a controller
used in my burner control system.
Figure 2 is a vertical sectional view on the line
4. 0 2-2 of Figure 1, showing the parts on an en
larged scale.
Figure 3 is an enlarged sectional view on the
line 3-3 of Figure 1.
45
Figure 4 is a diagrammatical view of the parts
in Figure 1 in a different position.
Figures 5 and 6 are similar diagrammatical
views, showing still different positions; and
Figures '7 and 8 are electrodiagrammatical
50 views showing the control system adapted for low
voltage and highvoltage room thermostat cir
cuits respectively.
On the accompanying drawing I have used the
reference numeral ID to indicate a switch casing. _
55 Within the casing ID a base l2, preferably of
5
Zll being secured to the other end of the bimetal
element to‘ secure magni?cation of the motion
thereof.
The arm ill extends through a slot 22 in the
casing it, and a slot 24 in the base 62, to a
position within the casing ll]. Within the casing
it it has 2. depending extension 26 connected to
one end of a flexible strap 28. The strap 28 ex
tends around and frictionally engages a spindle
36 of a shield S. The shield S has a second,
5
spindle 32, the spindles being mounted in bear- 20
ings 34.
The other end of the ?exible strap 28 is con
nected by a spring 36 to a pin 38. One of the
bearings 34 is provided with a pair of stop pins
40 and 42.
'
25
From the construction of the parts thus far
described, it will be obvious that upon the tem
perature rising and the bimetal element I6 open
ing, the spindle 30 will be rotated clockwise as
in Figure 2, for swinging ‘the shield S from the CO 0
vertical position of Figure 2 to the horizontal
position of Figure 3, and from the stop pin 40
to the stop pin 42. Thereafter the arm 20 can
move farther, the strap 28 merely slipping rela
tive to the spindle 30.
35
Upon a subsequent reduction of temperature v
affecting the bimetal element IS, the arm 20 will
move downwardly, thus initially returning the
shield to the position of Figure 2, and thereafter
the strap 28 will again slip relative to the spindle 40
30, the spring 36 acting to retract the strap.
Below the shield S is a heater H, such as a
resistance wire in zigzag formation and suitably
supported at its ends. Above the shield S is a
bimetal actuator 44 having one end a ounted on 45
a stationary projection 46 of the base l2. The
other end is free to warp from the position of
Figure l to the positions of Figures 5 and 6, upon
being heated to an intermediate and maximum
degree respectively.
50
The actuator 44 operates a switch arm 45 piv
oted at 48 and carrying a spring arm 50. The
spring arm 50 is operable to close the burner
switch contacts BS, which in most installations
operates a motor M as shown in Figures 7 and 8. 55
2
2,076,968
This motor usually blows air and pumps fuel to
the burner.
A safety switch SS is provided, and it also is
If combustion fails after it is established, the
shield S will return from the position of Figure 5
operated by the arm 5|! through a link connec
tion 52. The link is shouldered at 53, and there
by has a lost motion connection with a spring
arm 54 of the safety switch through a perfora
tion of which, the left end of the link extends.
To provide snap action for the burner switch
BS an armature 56 may be provided on the leaf
energization of the heater H to further warp the
spring 50, and is a?'ected by a permanent mag
to the position of Figure 6, thereby permitting
element 44, as in Figure 6, whereby the safety (R
switch is opened and the burner thus shut down.
It will then take some time for the safety switch
to be reclosed because of the residual heat open
ing it further, and the contacts being closed only
after the heat has been lost to a su?lcient ex
tent to permit the position of Figure 5 to be re
net 58 in the usual manner. The burner switch
BS and the safety switch SS are connected in
sumed. During this period purging of the fur
the circuit of the motor M by wires 0, b, c, and
position for recycling.
d.
nace takes place and the controller is then in
The wires 11 and d are connected with cur
If combustion does not occur in the first place, 15
the shield S will remain in the position of Figure
4, and finally the warp element 44 will assume
be connected to the. secondary of a transformer - the position of Figure 6, thus opening the safety
T and the heater H by wires 0 and h, as in Figure switch and the purging period will come into ef
7, or may be connected as in Figure 8 by these fect as above described. The burner will then 20
wires with the supply wires e and I, if the room recycle. An additional means, of course, can be
thermostat and heater are designed for line volt
provided to lock the controller in open position
age rather than for stepped down voltage of the if a number of recycles does not produce combus
rent supply wires e and f.
A room thermostat is illustrated at RT. It may
transformer secondary.
Practical operation
In the operation of my burner control system
the parts are normally in the position of Figure 1.
Upon a call for heat by the room thermostat a
circuit is traceable through the following ele
ments in Figures 7 and 8: a, H, RT and h.
This energizes the heater so that it causes the
element 44 to warp from the position of Figure 1
to the position of Figure 4 in which the burner
Li switch BS has just been closed. This will cause
the burner to operate and the element 44 will
tion establishment.
It is obvious also from the foregoing that nu
25
merous changes might be made in the construc
tion, arrangement and operation of the parts,
and it is my purpose to cover by my claims any
modifications in structure or use of mechanical
equivalents, which may reasonably come within
the scope of my invention and of the claims.
I claim as my invention:
1. In a burner control switch structure, a nor
mally open switch, a normally closed safety
switch operable to de-energize the burner cir 3 5
cuit, a slow acting actuator for said first switch
continue to move but will not yet open the safety ' and said safety switch for first closing the first
switch, because it will be noted that the shoulder switch and then opening the safety switch,
.53 adjacent the left end of the link 52 has not means for effecting operation of said actuator
yet engaged the spring 54. The switch is de
and means responsive to combustion if estab 40
signed so that it will take about a minute and lished for arresting the operation of said ?rst
a half for the shoulder 53 to engage the spring
54 after the burner switch BS is closed. This
period, of course, can be changed as desired by
properly proportioning the parts.
If combustion occurs within the minute and a
half period, the shield S will be rotated to the
position of Figure 5, thus shielding the element
44 from the heat of the heater H. The degree of
shielding can be controlled in different ways,
means after said actuator has closed said first
switch.
2. In a burner control switch structure, 9. nor
mally open switch, a normally closed safety
switch operable to de-energize the burner cir
cuit, a slow acting actuator for said ?rst switch
and said safety switch for first closing the first
switch and then opening the safety switch, an
electro-responsive heating means for actuating '
said actuator upon energization of said electro
a blackened or darkened surface 51 for the upper . responsive heating means, and means for ar
side of the shield in Figure 3, and a reflecting resting the operation of said electro-responsive
surface 59 for the lower side. The heat from the heating means after said actuator has closed
heater will then be reflected as indicated by said first switch, comprising a shield interposed It Li
arrows 7', while that of the bimetal element 44 between said electro-responsive means and said
will be absorbed.
actuator, said last means being responsive to
maximum shielding being secured by providing
If the above described re?ecting and absorbing
action is carried out to the maximum, then the
V bimetal 44 will warp to its original position, thus
causing intermittent operation of the burner
while the room thermostat is in closed position,
while if it is reduced to some extent, as for in
stance by omitting the blackened and re?ecting
. surfaces 51 and 59 respectively, or by providing
perforations 60 in the shield S, some heat can
still be supplied from the heater H to the bimetal
44 to keep it in the positions of Figures 4 and 5,
so that the burner switch will remain closed and
the safety switch likewise remain closed, while
the room thermostat is in a closed position.
Thereafter when the room thermostat opens,
the burner switch will be opened by the loss of
heat from the bimetal element 44 and the orig
75 inal position of Figure 1 will be assumed.
combustion establishment.
3. In a burner control switch structure, a nor
mally open switch, a normally closed safety
switch operable to de-energize the burner cir
cuit, a slow acting actuator for said first switch
and said safety switch for ?rst closing the first
switch and then opening the safety switch, an
electro-responsive heating means for actuating (25
said actuator upon energization of said electro- '
responsive heating means, and means for ar
resting the operation of said electro-responsive
heating means after said actuator has closed
said first switch, comprising a shield interposed
between said electro-responsive means and said
actuator, said last means being responsive to
combustion establishment, the side of said shield
facing said electro-responsive heating means be—
ing heat re?ecting.
3
4.1a a burner controller, a normally open
switch, a normally closed safety switch oper
able to de-energize the burner circuit, a slow
acting actuator for said ?rst switch and said
safety switch for ?rst closing the ?rst switch
and then opening the safety switch, an electro
responsive heating means for actuating said ac
tuator upon energization of said electro-respon
sive heating means, and means for-arresting the
resistance element and the warp element upon
combustion establishment.
8. In a burner controller of the character dis
closed, a normally open switch, a normally closed
safety switch operable to de-energize the burner
circuit, a warp element responsive to heat and
operable upon warping to close said ?rst switch
and then open said safety switch, a resistance
element which, when energized, is operable to
10 operation of said electro-responsive heating
radiate heat to said warp element to cause warp
means after said actuator has closed said ?rst
switch comprising a shield interposed between
said electro-responsive means and said actuator,
said last means being responsive to combustion
15 establishment, the side of said shield facing
ing thereof, and means responsive to combustion
establishment for arresting the ?ow of heat from
said resistance element to said warp element, said
means comprising a shield interposed between the
resistance element and the warp element upon
combustion establishment, said shield preventing
at least a portion of the heat generated by said
resistance element from affecting said warp ele
ment.
said actuator being heat absorbing.
5. In a burner controller, a normally open
switch, a normally closed safety switch oper
able to de-energize the burner circuit, a slow
2o acting actuator for said ?rst switch and said
safety switch for ?rst closing the ?rst switch
and then opening the safety switch, an electro
responsive heating means for actuating said ac
tuator upon energization of said electro-respon
25 sive heating means, and means for arresting the
operation of said electro-responsive heating
means after said actuator has closed said ?rst
switch comprising a shield interposed between
said electro-responsive means and said actuator,
30 said last means being responsive to combustion
establishment, the side of said shield facing said
electro-responsive heating means being heat re
?ecting, and the side of said‘ shield facing said
actuator being heat absorbing. -
35
6. In a burner controller of the character dis
closed, a normally open switch, a normally
closed safety switch operable to de-energize the
burner circuit, a warp element responsive to
heat and operable upon warping to close said
a 40 ?rst switch and then open said safety switch,
a resistance element which, when energized, is
operable to radiate heat to said warp element
to cause warping thereof, and means responsive
to combustion establishment for arresting the
45 ?ow of heat from said resistance element to
said warp element.
7. In a burner controller of the character dis
closed, a normally open switch, a normally closed
safety switch operable to de-energize the burner
50 circuit, a warp element responsive to heat and
operable upon warping to close said ?rst switch
and then open said safety switch, a resistance
element which, when energized, is operable to
radiate heat to said warp element to cause warp
55 ing thereof, and meansresponsive to combustion
establishment for arresting the ?ow of heat from
said resistance element to said warp element, said
means comprising a shield interposed between the
10
9. In a burner control device, a normally open
burner switch, a normally closed safety switch, a
bimetal warp- element for closing said burner
switch and then opening said safety switch upon
being heated, a heater for said bimetal warp ele
ment, and means responsive to combustion es
tablishment for at least reducing the heating
effect of said resistance element on said bimetal
warp element.
’
10. In a burner control device, a normally open
burner switch, a normally closed safety switch, a i
bimetal warp element for closing said burner
switch and then opening said safety switch upon
being heated, a heater for said bimetal warp ele
ment, and means responsive to combustion estab
lishment comprising a shield interposed between
said resistance element and said bimetal warp
element and temperature responsive means for
actuating said shield to its interposed position.
11. In a controller of the kind disclosed, a
heating element, a safety switch, an actuator i
for said safety switch responsive to heat generated
by said heating element, a shield for shielding
the heat of said heating element from acting
and means responsive to said actuator upon com
bustion establishment for moving said shield to
its effective position.
12. In a controller of the kind disclosed, a heat
ing element, a safety switch, an actuator for said
safety switch responsive to heat generated by said
heating element, a shield for shielding at least a
part of the heat of said heating element from act
ing upon said actuator and means responsive to
combustion establishment for effecting movement
of said shield to its shielding position and respon
sive to combustion failure to effect movement
thereof to its non-shielding position.
BURTON E. SHAW.
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