Combustion – With supporting bracket – leg – hook – strap or clip
Reexamination Certificate
2000-02-18
2001-09-25
Lazarus, Ira S. (Department: 3743)
Combustion
With supporting bracket, leg, hook, strap or clip
C431S355000, C431S278000, C431S266000, C431S154000
Reexamination Certificate
active
06293784
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to pilot assemblies, and, more particularly to pilot assemblies of the type having a changeable pilot orifice member.
BACKGROUND OF THE INVENTION
Gaseous fuel (hereafter for simplicity, gas) burning devices, such as conventional hot water heaters and gas fireplaces, typically burn natural gas or propane. Pilot assemblies are conventionally mounted in, and used to light, such gas burning devices. A conventional pilot assembly includes a pilot which continuously burns gas at a low rate to provide a pilot flame. The pilot flame in turn lights an adjacent main burner when gas is supplied to the main burner.
As a convenient example of a conventional environment for such a pilot assembly, a conventional gas fireplace GF (
FIG. 7
) includes a floor
8
, a fireplace box
9
extending upwardly from the floor
8
, and conventional fireplace hardware
10
mounted in the fireplace box
9
. The box
9
encloses sufficient volume for the fireplace hardware
10
and fireplace flames. The fireplace hardware
10
includes a grate
11
(in broken lines) standing on the floor
8
, imitation noncombustible logs
12
(in broken lines) resting on the grate
11
, a main burner
13
mounted to the floor
8
in substantially hidden relation behind the grate
11
and logs
12
, and a pilot assembly
15
. The main burner has plural gas flame producing nozzles
14
, some adjacent the pilot assembly
15
.
A typical conventional pilot assembly
15
(
FIG. 8
) includes a horizontal mounting bracket
17
fixed by any conventional means, not shown, with respect to the main burner
13
. The pilot assembly
15
is substantially hidden behind the main burner
13
. The assembly
15
includes a pilot
19
, an ignitor
21
, a thermocouple
22
, and a thermopile generator
23
, which are fixed on, and extend vertically through, the mounting bracket
17
in side-by-side relation.
The pilot
19
(
FIG. 8
) includes a one piece housing
27
extending vertically through and fixed to the central portion of the bracket
17
. A semirigid, metal, gas supply tube
28
connects the bottom of the pilot housing
27
through a conventional pilot valve V to a conventional gas source GS. A typical pilot valve V is spring biased closed (to block gas flow to the pilot
19
), but can be opened manually and can be held open electrically (to allow gas flow to the pilot).
FIG. 8
schematically shows a suitable conventional pilot valve V comprising a spring biased closed valve core C
1
interposed between the gas source GS and pilot supply tube
28
, and a manual opener (e.g. push button) B
1
and electromagnetic hold-open (e.g. solenoid) E
1
actuable to respectively open and hold-open the valve core C
1
against its spring S
1
.
The upper end of the pilot housing
27
normally emits a pilot flame (not shown) fueled by gas supplied through the open valve V and tube
28
. A pilot flame target
31
is fixed atop the housing
27
to direct the pilot flame laterally (to the right and left and forward out to the page in
FIG. 8
) along paths from the target
31
. The top of the ignitor
21
(
FIG. 8
) is adjacent one side (the left side in
FIG. 8
) of the target
31
, for igniting gas flow therefrom to establish the pilot flame of pilot
19
. The tops of the thermocouple
22
and thermopile generator
23
closely flank the target
31
(FIG.
8
), so as to be in the pilot flame path from opposite sides of the target
31
and with the ignitor
21
snugly spaced between the thermocouple
22
and target
31
. The front of the flame target
31
is adjacent ones of the gas outlet nozzles of the main burner
13
, such that the forward directed flame pilot flame component ignites the main burner
13
.
An electrically insulated wire
24
(
FIG. 8
) electrically couples the bottom of the ignitor
21
to the output of a conventional ignitor voltage source, here for example a conventional, manually actuable, push button, piezo-electric voltage source PZ, grounded to the bracket
17
. Given a supply of gas through the pilot valve V to the pilot
19
, manual actuation of the piezo voltage source discharges an electrical spark between the tops of the ignitor
21
and pilot
19
, thereby igniting the pilot gas flow and starting the pilot flame.
A relatively stiff wire
25
extends from the bottom of the thermocouple
22
to the control input of the electromagnetic hold-open E
1
of pilot valve V. The thermocouple
22
, when heated by the pilot flame from pilot
19
, supplies a voltage (typically in the range of millivolts) to the solenoid E
1
to maintain the valve V open and so maintain gas flow to the pilot and keep the pilot flame on. If the pilot flame becomes extinguished, the thermocouple
22
cools, its voltage output drops, and the solenoid E
1
relaxes and the spring S
1
closes the valve V and shuts off gas flow to the pilot
19
.
The bottom of thermopile generator
23
(
FIG. 8
) connects through a heat shielded, relatively stiff, electrically insulated wire pair
26
to a main gas safety valve MV interposed between the conventional gas source GS and the main burner
13
. The thermopile generator
23
responds to pilot flame heat to electrically open the main valve MV to supply gas from the gas source GS to the main burner
13
and responds to lack of pilot flame heat to close the valve Mv and thus shut off gas flow to the main burner
13
. The main safety valve MV may be a conventional solenoid valve (like pilot V but without the manual opener B
1
) comprising a valve core C
2
spring biased closed by a spring S
2
and openable by a solenoid E
2
.
Typically, a manual control MC, in the form of a manually adjustable valve, is in series with the main safety valve MV, between the gas source GS and main burner MB, to allow the human operator of the fireplace GF to turn on and off, and vary the flame height of, the main burner MB.
The top and bottom ends of the one-piece pilot housing
27
(
FIG. 9
) are spaced above and below the bracket
17
. The housing
27
has a radially inwardly stepped, upper housing portion
45
. The housing
27
also has a stepped axial through passage
29
. The passage
29
has a substantially cylindrical top portion
42
, an enlarged-diameter midportion
43
and a further enlarged-diameter, bottom opening, internally threaded recess
44
. The portions
42
and
43
are separated by a tapered annular step
46
. The midportion
43
and recess
44
are separated by an annular step
47
, the upper portion of which is tapered upward and inward. The open top
48
of the passage
29
acts as the ignited gas/air mixture (flame) outlet nozzle of the pilot
19
.
The pilot flame target
31
comprises a semi-circular base
38
which is fixed, by any convenient means, such as welding, to the upper housing portion
45
. The target
31
has an inverted trough-like, pilot flame deflector
39
fixedly upstanding from the base
38
and spaced above the pilot flame nozzle
48
for deflecting the pilot flame laterally (to the left and right in
FIG. 9
) toward the ignitor
21
, thermocouple
22
and thermopile generator
23
and forwardly (out of the page in
FIG. 9
) toward the main burner
13
.
At least one air supply aperture
32
opens radially through the peripheral wall of the housing
27
and into the midportion
43
of the passage
29
. The aperture
32
may be above the bracket
17
as here shown, or below it.
An inverted cup-shaped, pilot orifice-containing member
33
includes a substantially cylindrical peripheral wall
35
, a horizontal top end wall
36
, a central orifice
34
preferably centered in the end wall
36
, and a radially outwardly and downwardly flared bottom flange
40
. The orifice member
33
is assembled in the pilot housing
27
by upward insertion through the threaded bottom recess
44
. When so installed, as seen in
FIG. 9
, the top end wall
36
, with its orifice
34
, is located closely below the air aperture
32
, the peripheral wall
35
is in snug sliding engagement with the lower portion of the passage midportion
43
, and the bottom flange
40
sn
Cocks Josiah C.
Flynn ,Thiel, Boutell & Tanis, P.C.
Lazarus Ira S.
LandOfFree
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