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Патент USA US2109239

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Feb. 22, 1938. -
'
c, SCHOLL
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2,109,239
AIR CONTROL MEANS FOR COMBUSTION APPARATUS
Filed Oct. 19, 1935
2 Sheets-Sheet 1
CIWENTOEI
CV0»? So?a/2
Feb; 22, ‘1938;
C. SCHOLL
AfR CONTROL MEANS FOR COMB UTSTION APPARATUS
Filed Oct. 19, 1935
2,109,239
2 Sheets-Sheet 2
54
P4 ‘
35
- #26
29’
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36
23v
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(ATTOWJ’S
‘ Patented p.512, i938 '
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‘2,109,239 '
UNITED STATES PATENT OFFICE i
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2,109,239
Am. common-trams FOR. COMBUSTION
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APPARATUS
Clark Scholl, Springfield, Ohio, assignor to ‘The. '
Steel Products Engineering Company, $pring
?eld, Ohio, a corporation of Ohio
.
Application October 19, 1935, Serial No. 45,776
13 Claims,‘ (01. 230-114)
The present invention relates to improvements thereby permitting the fuel bed to build up to
in automatic air control means forv combustion the proper depth, and‘ preventing substantial
apparatus, and has particular reference to a combustion losses because of an undue volume
' new and improved automatic damper for control-
5 ling the supply of air ‘under pressure to the fuel
bed of a furnace, as for-example in the retort
of an underfeed coal stoker. '
'
A more speci?c object resides in the provision 5
in an air blower of a novel rotary inlet damper
automatically adjustable in accordance with the
It is well recognized that a proper ratio of
fuel ,and ?nely dispersed air must be maintained
10 in order to obtain e?icient and satisfactory combustion. Such ratio is di?icult to obtain in
stokers with forced draft because of variations
in operating conditionsv in?uencing the amount of
air supplied to the combustion zone.
of excess air.
In one
15 common type of .underfeed stoker, fuel is fed
through a duct into the bottom of a vretort to
varying height of a liquid which is responsive
in level to the differential between the static
pressure of the air delivered by the blower and 10'
the pressure of the atmosphere.
A general object resides in the provision of a
new and improved damper of the foregoing char
acter/which is simple and inexpensive in con-
‘
struction, and sensitive, accurate and reliable in 15
operation.
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>
form a fuel bed, and air for‘ ‘combustion is supFurther objects and advantages vwill become
plied under pressure by ayfan or blower through - apparent as the description proceeds.
a duct to a plenum chamber, and then through
In ‘the accompanying drawings, Figure 1 is a
20 tuyere openings into the bed. When the fuel bed plan view of an underfeed stoker provided with 20
is heavy and dense, the static pressure of the air automatic air supply means embodying the fea
will be relatively high, and at times may reach tures of my invention.
the maximum that the blower can develop. ConFig. 2 is a fragmentary vertical sectional view
. versely, when the fuel bed is thin and porous, its
25 resistance to the passage of air is greatly re-
on an enlarged scale taken along line 2-2 of Fig.
1, and illustrating the automatic air supply 25
duced, and hence the static pressure of the air‘
means.
may be very low. The volume of air delivered
by the blower varies inversely with the static
Fig.3 is an axial sectional view of the blower
taken along line 3-3 of Fig. 2.
'
‘
"
pressure in the air passages. Thus, when the .
Fig. 4 is a ‘horizontal sectional view taken
30 fuel bed is heavy, and the volume of air should along line 4-4 of Fig. 2.
"
.
30
be correspondingly high, the ‘actual volume of air
supplied is relatively low. When the fuel bed is
light, and a relatively small amount of air is required, the amount of air actually supplied may
35 be considerably in excess of that required for
combustion, thus resulting in serious heat losses.
v'I'he condition of the fuel bed is determinedyby
the kind of fuel that is used, the rate of fuel
feed, and the rate of combustion.
40
One of the primary objects of the present
invention resides in the provision of novel means
for supplying air under pressure automatically
in accordance with the conditions of the fuel
bed, thereby avoiding the inconvenience of and
45 necessity for manual supervision and adjustment, and the undesirable consequences of failure
to make proper adjustments.
Another object is to provide an. automatic
damper for the air supply means which is respon50 .sive to the static pressure of the air passing tov
the fuel bed so that when the static pressure
increases, the damper is moved correspondingly
toward open position, and when the static presiii Cl
sure drops, the damper is moved correspondingly
toward closed position to restrict the ?ow of air,
Fig. 5 is a vertical sectional view of a modi
?ed form of the invention.
Referring more particularly to they drawings,
the underfeed stoker disclosed in Fig. 1 has a
burner l0 comprising an upwardly opening ?re 35
pot or retort II, a plenum chamber l2 surround
ing the pot, and tuyéres i3 opening from the
chamber to the top of the pot. Solid fuel, such
for example as coal, is fed by a conveyer l4 from
a hopper I5 through a duct l6 into the bottom 40
of the ?re pot l l to form a fuel bed. Air under
pressure is supplied by a fan or blower I1 through
a duct ‘ It to the plenum'chamber l2 for dis
charge through the tuyeres 13 into the top por
tion of the fuel bed. The conveyer Hand blower 45
I‘! are driven in timed relation through a variable
speed mechanism Hi from an electric motor 20.
Preferably, the blower H, the variable speed '
mechanism l9, ' and the motor 20 are rigidly
mounted on the base of the hopper i5.
50
'The blower H, which constitutes the air sup
ply means, may be of any suitable character, and
is herein shown as of the rotary type. More par
ticularly, the blower l1 comprises a generally
cylindrical housing 2| which has a tangential 55
2
2,109,239
outlet 22 connected to the duct i 8, and which is
is de?ned by registering openings in the contact
formed in one side wall with a circular opening ' ing walls of the duct I8 and the reservoir 40. The
chambers 42 .and 43 preferably are disposed in
23. A rotor or fan wheel 24 is ?xed on- a shaft
25 for rotation within the housing 2|, and com
‘ prises a plurality of annularly arranged periph
eral vanes 28 de?ning a hollow interior space 21
open at one side and closed at the other side.
The shaft 25 is driven by the motor 28. Attached
in fixed position to the housing 2| about the front
10 opening 23 is a ring 28 having an inwardly ta
pering conical ?ange 28 for directing air_to the
interior space of the rotor 24.
An important feature of the present invention
resides in the provision of novel air control
15 means, preferably in the form of a damper, which
‘ opposite ends of" the reservoir 40, and hence are
located side by side with] an interconnecting pas
sage 48 beneath the partition wall 4|. The ad
justing member 39 is shown in the form of a
?oat in the chamber 43, which is of greater,
height and of less horizontal area than the cham
ber 42, and has a vertical connecting rod or stem
50 extending upwardly loosely through an open
ing 5| in the cover 45. Pivotally connected at
one end to the upper end of the rod 50 is a lever
52. The other end of the lever 52 is connected
through a swinging link 53 to the damper plate 15
32. Intermediate its ends, the lever 52 is mount
serves to control the volume of air supplied
through the duct l8 to the fuel bed, and which is
ed for pivotal movement on a horizontal axis
automatically adjustable in accordance with
between two centers 54 adjustably secured in
changes in the static pressure of the air. The
20 damper may be of any desired form or type, and
may be located in any suitable position of control‘
two upstanding arms 55 of a bifurcated bracket
56 rigidly mounted on one end of the reservoir 40. 20
It will be seen that if the fuel bed is light and
in- the air supply system. In the preferred form
of the invention, the air supply is controlled at
the inlet of the blower I‘! by a damper 30 of the
25 rotary type. Preferably, the damper 33 com
prises a ?xed plate 3| integral with the ring 28,
porous, the static pressure in the duct I8 will be
low. As a result, the ?oat 39 will be'lowered to
which constitutes a rim therefor, and a ?at cir
cular rotary plate 32 disposed against the outer
face ofv the plate.3l. The ?xed plate 3| is formed
30 with an inwardly extending axial hub 33 sup
porting a ?xed shaft 34 on the outer end of which
the plate 32 is suitably joumaled. Also secured
to the shaft 34 within the wheel 24 is a generally
conical de?ector 35 for directing the incoming
air toward the vanes 26. The ?xed and movable
plates 3| and 32 are formed respectively with
restrict the flow, of air through the damper 38.
Hence, the supply of I air to the fuel bed, al
though adequate, will be cut down, thereby giving
the fuel bed a ‘chance to build up to the proper
depth, and preventing an undue volume of excess
air from passing through the fuel bed and di
luting the products of combustion. As the fuel 30
bed increases in depth and the holes ?ll up, the
static pressure increases, thereby increasing the
damper opening. Thus, the correct damper ad
justment is automatically maintained at all
' times.
The adjustment/is substantially in ac
cordance with the condition of the fuel‘bed, and
radial uniformly peripherally spaced openings 36 takes, into account the kind‘ of fuel burned, the
and 31 adapted to be moved progressively into rate of vfeed and the rate of combustion in so far _
different degrees of communication between zero as these factors effect the condition of the fuel
’
40 and full registration.
bed. ‘The aggregate area of the openings 35, and 40
The damper plate 32 is rotatably adjustable to ’ also of the openings 31, preferably is at least as
adjust the effective air inlet and hence the air great, if not greater, than the area circumscribed
intake of the blower IT in accordance with varia
tions in the static. pressure of the air supplied to
the fuel bed.
by the ?ange 28 so that there will be no restric- I
tion in the flow of the air vby the damper 30 when
In the preferred embodiment of ' ‘the latter is wide open.
the invention, this is accomplished through the
medium of a liquid 38 which tends to seek dif
ferent levels in accordance with changes in the
differential between the static pressure of the
air delivered by the blower l1 and atmospheric
pressure, and which actuates an adiusting mem
ber 38 operatively connected to the damper plate
32. The liquid 38 is placed in a reservoir 40 which
is divided by apartition 4! at the top into two
chambers 42 and 43 intercom'municating under
the liquid level. One chamber 42 is sealed from
the atmosphere, and is connected above the liq
In the modi?cation shown in Fig. 5, the auto
matic' damper controls the ?ow of air from the
blower I‘! rather than the air entering the blower.
The damper comprises a plate 32“ mounted with
in the duct l3 for pivotal movement about a hori
zontal axis 34" into different angular positions
relative to the path of air ?ow. The operating
mechanism for the pivotal damper plate 32*, ex
cept for minor di?'erences hereinafter described,
is closely similar to that for the rotary damper 55
plate 32, and'hence like parts thereof vare desig
nated bythe same reference numerals plus the
.uid level through a passage 44 with the interior‘ subscript a.
of the duct l8. The other chamber 43, although
In this form, the reservoir 40‘ is mounted von
substantially closed by a cover 45, is open at the the top of the 'duct l8, and the passage 44* opens 60
top to the atmosphere. When the'stoker is idle, from the duct upwardly through one end‘ of the
and atmospheric pressure prevails in the duct i8, chamber 42' to the'top of the liquid 38-. The
the liquid 38 will assume the same level in both cover 45' for the chamber 43' has a central cylin
drical upstanding dome 51 formed ‘with a series
chambers 42 and 43 as indicated at 48. How
65 ever, when the stoker is operating, the static
pressure in the duct l8 will exceed atmospheric
pressure more or less, and will depress the liq
uid in the chamber 42 accordingly. for example
to the level 41, and thereby will cause a corre
70 sponding rise of the liquid in the chamber 43 to
» the level 48.
The adjusting member 39 is mov
able in response to the variations in liquid level.
In Fig. 2, the reservoir 40 is elongated and rec
tangular, and extends along and is directly se
75 cured to one side of the duct II. The passage 44
of peripherally spaced openings 5|,‘ to the atmos 65
phere. The damper plate 32‘ is operable by a rod
58 to which it is pivotally connected at one side
of the axis 34', and which extends upwardly from
the duct l8 through a vertical tube‘ 59 encircled
by the annular ?oat 39-. The lower end of the 70
tube 53 is threaded into a ?anged opening 53 in
the bottom of the chamber 43" and in registra~
tion with an opening 5| inthe top wall of the
duct l8, and the upper end extends to. above the
maximum possible liquid level. ' An inverted cup 75
2,109,239
62, ?xed centrally on the top of the ?oat 39a,
and sealed internally from the chamber 43“, is
pivotally connected to the upper end of the rod
3
rotary plate to effect a vproportionate adjustment
of said inlet area».
5. An automatic damper for forced draft stokers. , >
comprising, in combination with a rotary blower
having a discharge duct and having an axial
tube 59 or into the dome 51.
atmospheric air inlet, a ?xed damper plate ex
I claim as my invention:
1. An automatic damper for forced-draftstok tending across said inlet, a rotary damper plate
ers comprising, in combination with a rotary mounted in cooperative relation against said
blower having a discharge duct and an axial - ?xed damper plate, said plates having air inlet ‘
openings movable respectively into di?erent de 10
10 atmospheric air inlet, a ?xed damper plate ex
tending across said inlet, a rotary damper plate grees of registration to de?ne the e?ective air
mounted in cooperative relation against said ?xed inlet area, means de?ning two chambers con-'
taining a liquid in intercommunication below.
damper plate, said plates having air inlet open
ings movable respectively into different degrees the liquid level, one chamber being closed to the
of registration to de?ne the e?ective air inlet atmosphere and being connected above the liquid 15
area, and means located outside of said duct for level to said duct, the other chamber being open
above the liquid level to the atmosphere, a float
automatically adjusting said rotary plateto in
on the liquid in said other chamber, and means
crease and decrease said air inlet area respective
ly in accordance with increases and decreases in operatively connecting said ?oat to said rotary
the static pressure of the air discharged from said plate to control said air inlet area in accordance 20
with changes in the static pressure in said duct
blower.,
,
to increase the air ?ow upon an increase in static
2. An automatic damper for forced-draft stok
ers comprising, in combination with a rotary pressure and to reduce the air ?ow upon a de
blower having a discharge duct and having an crease in static pressure.
6. An automatic damper for forced draft stok 25
air inlet, a ?xed damper member extending
ers
comprising, in combination with a blower
across said inlet, a rotary damper member mount
ed in cooperative relation against‘ said ?xed having a discharge duct and having an air inlet,
damper member, said members being ?at and a ?xed damper member for said inlet, a rotary
Y58, and is adapted to telescope loosely onto the
having air inlet openings movable respectively
into di?erent degrees of registration to de?ne
the e?ective air inlet area, a stationary reservoir
adapted to contain a liquid varying in level in
accordance with changes in the static pressure
of the air ?owing through said duct, and means
operable in response to variations in the level of
said liquid for automatically adjusting said ro
tary member.
,
I 3. An automatic damper for forced draft stok
ers comprising, in combination with a rotary
blower having a peripheral discharge duct and
having an‘ air inlet in one side, a ?xed damper
member for said inlet, a rotary damper member
mounted in cooperative relation with said ?xed
damper member, said members having air inlet
openings movable respectively into di?erent'de
damper member mountedin cooperative relation
with said ?xed damper member, said members 30
having air inlet openings movable respectively
into di?erent degrees of registration to de?ne
the effective air inlet area, means de?ning two
chambers containing a liquid in intercommuni
cation below the liquid level, one chamber being 35
relatively large and shallow, being closed to the
atmosphere and being connected above the liq
uid level to said duct, the other chamber being
relatively small and deep and being under a
substantially constant pressure above the liquid 40
level, a ?oat on the liquid in said other chamber
and spaced from the walls thereof, and move
ment multiplying means operatively connecting
said ?oat to said rotary member to control said
air inlet area in accordance with changes in the 45
static pressure in said duct.
7. An automatic damper for forced-draft stok
inlet area, a stationary reservoir having two liq- Y
uid chambers in intercommunication below the ers comprising, in combination with a forced
liquid level, one of said chambers being closed draft supply means having a discharge air-?ow
to the atmosphere and being in communication duct and an air inlet, a rotary damper for ad
above the liquid level with said duct, the other of justing the effective area of the air inlet, a liquid
said chambers being open to the atmosphere, reservoir having a partition de?ning two liquid
and means operable in response to variations in chambers intercommunicating below the liquid
liquid level in one of said chambers for adjusting level, one of said chambers being closed to the
said damper automatically in accordance with atmosphere and in communication above the 55
variations in the static pressure of the air in said liquid level with said duct, the other of said cham
bers being open above the liquid level to the
duct.
atmosphere, a ?oat in said other chamber, a lever
4. An automatic damper for forced draft stok
ers comprising, in combination with a rotary pivotally mounted intermediate its ends on said
blower
having a hollow propeller and having a reservoir and having a link connection at one 60
Ci)
casing with a peripheral discharge duct and an end with said ?oat and a link connection at the
air inlet opening in one side, a ?xed damper other end with said damper, whereby vertical
plate secured to said casing across said inlet and movement of said ?oat will e?ect a proportion
having a conical ?ange for directing air into ate angular adjustment of said damper.
8. An automatic ‘damper for forced draft stok "105
said “propeller, a rotary damper plate mounted
in cooperative relation against said ?xed damper . ,ers comprising, in combination with a blower
‘having a discharge duct and an air inlet, a
plate, said plates having air inlet openings mov
damper for adjusting the effective area of the
able respectively into different degrees of reg
istration‘ to de?ne the e?ective air inlet area, air inlet, a liquid reservoir having a partition de
the aggregate area of the openings in each ?ning two rectangular liquid chambers juxta 70
posed end to end and intercommunicating below
damper plate being no less than the area cir
cumscribed by said ?ange, and means out of the the liquid level, one of said chambers being rela
grees of registration to de?ne the e?’ective air
path of air ?ow through said duct and adjust
able in response to variations solely in the static
pressure of the air in said duct for adjusting said
tively large and closed to the atmosphere and
in communication above the liquid level with said
duct at the discharge side of said damper, a ?oat -
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2,109,239
in the other chamber which is relatively small
and open above the liquid level to the atmosphere,
and movement multiplying means operatively
connecting said damper and said ?oat for syn
chronous movement, whereby vertical movement
of said?oat in response to varying liquid levels
will e?ecta proportionate adjustment of said
damper.
9. An automatic damper comprising, in com
10 bination with an air-?ow passage, an adjustable
damper for controlling the volume oi’ air ?owing
through said passage, a liquid reservoir having
two liquid chambers inte'rcommunicating below
the liquid level, one of said chambers being closed
15 to the atmosphere and in communication above
the liquid level with said passage at the outlet
side of ‘said damper, the other of said chambers
being open above the liquid level‘ to the atmos
phere, a ?oat in one of said chambers, a lever
'20 having a ?xed fulcrum and having pivotal con
25
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40
multiplying means to said damper to effect a
proportionate variation in the air inlet area.
12. An automatic damper comprising, in com
bination with an air duct and means for supply
ing air under pressure to said duct, a damper
pivotally mounted in said duct, a liquid reservoir
mounted on said duct and having a partition de
?ning two liquid chambers in intercommunica
tion below the liquid level, one of said chambers
being closed to the atmosphere and being in com
munication above the liquid level with the in
terior of said duct at the discharge side of said
damper, the other or said chambers being open
to the atmosphere, a tube communicating with
10
said duct and extending outwardly into said 15
other chamber to a point above the liquid level,
an annular ?oat mounted on the liquid in said
other chamber and encircling said tube, a cap
on said ?oat telescoping with and substantially
sealing said tube fromv the atmosphere, and a 20'
nections with said ?oat and said damper whereby pivotal link connection between said cap and said
movement of said ?oat in response to varying; damper extending through said tube, whereby
liquid levels will e?'ect ,a proportionate adjust
said damper will be moved toward open position
ment of said damper.
as said ?oat rises in response to an increase in
10. An automatic damper comprising, in com
static pressure in said duct.
bination with an air ?ow passage, an adjustable
13. An automatic damper comprising, in com
damper for controlling the volume of air ?owing bination with an air duct and means for supply
throughsaid passage, a reservoir having two liq— I ing air under pressure to said duct, an adjust
uid chambers of unequal height and of unequal able damper in said duct, a liquid reservoir
horizontal areas in intercommunication below the mounted over said duct and having two liquid 30
liquid level, the chamber or larger area being chambers in intercommunication below the liquid
closed to_the atmosphere and in communication level, one of said chambers being closedto the
above the liquid level with said passage at the atmosphere and being in communication above
outlet side of said damper, and a ?oat in the the liquid level with the interior of said duct, the
chamber of smaller area operable in response to other of said chambers being vopen to the at
variations in liquid level for adjusting said damp
mosphere, a tube communicating with said duct
er automatically in accordance with variations in
and extending into said otherv chamber to a
the static pressure of the air in said passage.
point above the liquid level, an annular ?oat
11. An automatic damper for forced-draft mounted in said other chamber and encircling
stokers comprising, in combination with a rotary said tube, and a connection between said damper 40
blower having an air inlet and a discharge duct,
a low pressurevair damper in control of all or the
air passing to said duct and adjustable to vary
the effective area 01’ said air inlet-from zero to
maximum, and means including a ?oat movable
in response to variations 'in the pressure of the
air in said duct and connected by a movement
and said ?oat extending through said tube,
whereby said damper will be adjusted synchro
nously with the vertical movement of said ?oat
in response to variations in the static pressure in
said duct.
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CLARK SCHOLL.
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