Note: Descriptions are shown in the official language in which they were submitted.
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This invention relates to a damper control arrangement
and in particular relates to a damper control arrangement includ-
ing means to selectively control the opening area o~ a flow-
through orifice. Even more particularly, this invention relates
to a damper con-trol arrangement which provides a selectively
buffered transition in a system when starting or stopping the
~low of fluid in the system.
In many applications it is desirable to provide for a
buffered transition when removing a fluid system from or returning
a fluid system to different preselected fluid flow conditions.
For example, in the filtering of a gas stream using cloth fabric
bags, it is desirable to avoid a sudden surge of gas when a gas
controlling damper arrangement is activated, the sudden surges
of gas causing the fabric filter bags to snap and consequently
weaken the fabric material. This weakening of the fabric is
intensified when the fabric material is one containing glass
fibers.
Prior art damper arrangements, such as bullseye
dampers and butterfly dampers, can only be made to function
satisfactorily by using an expensive time actuating means which
causes them to operate in a relatively slow manner. Even so,
butterfly dampers are particularly difficult to use becuase the
fluid flow rate does not change linearly wlth respect to the
change in position of the damper blade as most of the fluid is
controllable when ~he damper blade moves to a position substan-
tially parallel to the direction of flow of the fluid. Less
objectionable is the bullseye damper since its ~low rate changes
linearly over the entire damper blade stroke.
In order to provide a control arrangement for a damper
to selectively control the opening and closing of a flow-through
orifice to provide a selectively buffered transition in a system
when starting or stopping the flow of fluid therethrough, U.S.
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``` ~067~78
3,8981997 has been proposed utilizing electrical actuating means
to actuate the damper means for movement of the damper blade
from one position to another. In this reference, when the damper
~lade is in an open positionl a soIenoid is required to be
energized. Furthermorel when the device taught by the reference
is used in combination with a filter system utiLizing a baghouse
and the damper assembly is disposed in an inlet~air system to
the baghousel when a compartment is being cleaned the damper
is closed and one solenoid is de-energized, but a second solenoid
is requlred to be energized. When putting the system back on
stream and a soft-inflate is required, the one solenoid is
energized and the second solenoid is de-energized until a pre-
selected distance or preselected period of time has been satisfied.
Then, the energized solenoid is de-energized. After the cycle
is ready to end the low flow rate, the de-energized solenoid is
then re-energized to open the damper and remains in the energized
position during the normal operation of the system.
In the present invention, it is recognized that it is
desirable to provide a damper control arrangement for selectively
controlling the opening and closing of a flow-through orifice and
it is further recognized that it is desirable to provide a damper
control arrangement which is straightforward, inexpensive, readily
constructed and easily maintained.
The present invention advantageously provides a straight-
forward arrangement for a damper control arrangement which includes
means to control the opening and closing of flow-through an orifice.
The present invention further provides a damper contro] arrange-
ment which is inexpensive, sturdy, easy and quickly operable and
yet effective during operating conditions. The present invention
even further provides a damper control arrangement which is use-
ful where, for example, the gentle inflation of a gas filter bag,
as it is being put onstream, utilizes solenoid valves to maintain
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the damper in its fully closed position when said solenoids are
energized and a fully open or normal operating condition when
both solenoids are de-energized and at intermediate holding
positions of the damper assembly, one solenoid is energized and
another solenoid is de-energi2ed.
Various other features of the present invention will
become obvious to those skilled in the art upon reading the
disclosure set forth hereinafter.
More particularly, the present invention provides a
damper control arrangement comprising: a housing wall having an
orifice therein, a damper blade movably positioned selectively
between at least one open position and a closed position in
relation to the orifice, damper blade moving means in communica-
tion with the damper blade for moving the damper blade relative
to the housing wall, actuating means operable to actuate the
damper blade moving means for movement of the damper blade from
one position to another, the actuating means including control
means for the damper blade moving means actuated in response to
a first control circuit and a second control circuit wherein the
first control circuit includes means for de-energizing the
actuating means to a position to cause the selective opening of
the orifice by moving the damper blade a preselected distance,
means for energizing the actuating means once the damper blade
has traveled a preselected distance, and a timing device arranged
to maintain the damper blade at the preselected distance for a
preselected period of time before the actuating means is de-
energized whereby the damper blade is actuated to move to a second
open position, and, the second control circuit includes means for
energizing the actuating means to a position to cause the closing
of the damper blade.
Even more particularly, the present invention provides
a damper control arrangement comprising a housing wall having an
~06747~3
orifice therein, a damper blade movably positioned selectively
between at least one open posi.tion and a closed position in
relation to the ori~ice; damper blade moving means in communica-
tion with the damper blade for moving the damper blade relative
to the housing wall, actuating means operable to actuate the damper
blade moving means for movement of the damper blade from~one
position to another, the actuating means including control means
for the damper blade moving means actuated in response to a
first control circuit and a second control circuit wherein (1)
the first control circuit includes a normally open switch means
closed to a first position, the switch means in the first closed
position being in series with two branch circuits in parallel,
the first of the branch circuits including a normally open first
contact swltch and a first contactor actuating means whereby the
first contactor actuating means actuates the actuating~means to
a first position upon closing the normally open first contact
switch, the second of the branches including a normally open
limit switch and a first contact relay which operates the normal-
ly open first contact switch, the normally open llmit switch
being operable in response to selected movement of the damper
blade whereby when the damper blade moves a preselected distance
the limit switch is actuated to a closed position.thereby ener-
gizing the contact relay which closes the normally open first
contact switch, actuating the first contactor.actuating means
which in turn actuates the actuating means to its original posi-
tion' and, (2) the second control circuit includes the normally
open switch means closed to a second position, the first con-
tactor actuatlng means and a second contactor actuating means
whereby the ~irst and second contactor actuating means actuates
the actuating means to a second position upon closin~ the normal-
ly open switch means to the second position.
It is to be understood that the description of the
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`~ 1067478
examples of the present invention given hereinafter are not by
way of limitation and various modifications within the scope of
the present invention will occur to those skilled in the art
upon reading the disclosure set forth hereinafter.
Referring to the drawing
The Figure is an elevational view, partially in cross-
section, of one preferred embodiment of the invention of this
disclosure includin~ an electrical schematic for operating the
preferred embodiment.
The Figure of the drawing illustrates the struc-ture
of a damper assembly 2 operable in response to the operation of
the damper blade moving means, exemplified as fluid cylinder 4,
the fluid being generally either hydraulic or pneumatic. How-
ever, it is realized that the damper blade moving means may be
other mechanical means such as a motorized drive with appropriate
gearing. Fluid pressure for operation of the fluid cylinder 4,
as exemplified, is supplied from the actuating means, exemplified
as a single coil, three positions spring return to center, and
remote air pllot operated solenoid valve means 6 which is adapted
to supply fluid to compartment A of the cylinder 4 through line
8 and into the other compartment, compartment B, of the fluid
cylinder 4 through appropriate conduit piping 10, the compart-
ments A and B of cylinder 4 defined by the position of piston
means 82, to be discussed hereinafter.
Supply of fluid to the fluid-cylinder 4 is determined
by the position of the slideable valve portion 20 of the valve
means 6 in response to the operation of the coil solenoids 12
and 14. Solenoids 12 and 14 include biasing means 16 and 18,
respectively, whereby upon energization, the positioning of the
slideable valve portion 20 which is disposed within the housing
24, determines which conduits supplies fluid to the selected
compartment of the cylinder 4, as discussed hereinafter. It is
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also realized that the e~emplified actuating means 6 may be, ~or
example, a reversible starter if the damper moving means 4 is,
~or example, a motorized drive with appropriate gearing. It
will become apparent to those skilled in the art that even further
substitutions may be made with actuating means from the damper
moving means which are operable in response to electrical cir-
cuitry, which will be discussed hereinafter, without departing
from the scope and spirit of the present invention.
The valve means 6 includes five flow-through openings
26, 28, 30, 32 and 34 therein in the housing portion 24. Open-
ings 26 and 28 communicate with conduits 8 and 10, respectively,
openings 30 and 34 are in communication with exhaust conduits
36 and 38, respectively, and opening 32. is in fluid communicatlon
with a fluid supply source conduit 40, conduit 40 supplying the
pressurized fluid to the fluid cylinder 4 by means of the control
: valve 6. In the Figure, solenoid 14 including blasing means :
18, is further provided with slideable valve means 15 which
includes three flow-through openings 17, 19 and 21 therein.
Opening 17 communicates with a fluid supply conduit 29, conduit
29 supplying the pressurized fluid to a fluid cylinder 27 by
means of the valve means 15 and conduit 25. When solenoid 14
is energized, opening 21 is in fIow-through alignment with conduit
25 to exhaust the pressurized fluid from the fluid cylinder 27.
When solenoid 14 is de-energized, opening 19 is in flow-through
alignment with conduit 25 thereby supplying pressurized fluid
from the supply source conduit 29 through flow-through opening
. 17 to the fluid cyIinder 270
It is noted that when solenoids 12 and 14 are de-
energized a flow-through passage 48 i.s aligned for ~low-through
communication with conduit 40, the supply fluid conduit, and
conduit 10 with flow-through passage 46 being aligned between
openings.26 and 34 to provide for the exhausting of the fIuid
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78
from the fluid cylinder 4 through fluid conduit 8 and the exhaust
conduit 38. ~nerg.ization of solenoids 12 and 14 urges valve
portion 20 to a position within control valve means 6 so that
flow-through passage 44 is aligned with opening 32 and opening .
26 thereby providing fluid from conduit 44 to the fluid cylinder
4 through fluid condult 8 with flow-through opening 42 being
aligned with openings 28 and 30 providing for flow-through comm-
unication between conduit 10 and e~haust line 36. -When soienoid
12 is de-energized and solenoid 14 i9 energized, the slideable
valve portion 20 is locked in its original position, as illustra-
ted in the Figur~e,~and all openings to the control valve means 6
are closed off.
Means for energizing solenoids 12 and 14 is through
electrical circuitry hereinafter referred to as first and second
control circuits. Each of the circuits include the three-way
main control circuit switch 50, the first control circuit being
energized by actuating main control circuit switch 50 to a
closed position at contact 53 and the second control circuit
being energized by actuating main con:trol circuit swi.tch 50 to
a closed position at.52 and 54. : ::
rrhe first control circuit is comprised of two branch
circuits, the first branch circuit including a first contactor
actuating means, exemplified as solenoid co11 winding 78, coil
winding 78 being the actuating winding for solenoid 14. The
first branch circuit ~urther lncludes normally open contact
relay switch 56 which is operable in response to energization
of contact relay 62. Contact relay 62 including wind1ng 66 is
energized through the second branch electricsl conduit 64 which ~-
includes normally open limit switch 68 and normally open contact
switch 53. Thus, when the control switch 50 is closed to
position 53, coil 78 is maintained energized providing control
relay 62 is energized. Upon de-energization of contact relay 62,
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106747~
normally open contact switch 56 opens thèreby breaking the cir-
cuit which supplies electrical energy to the coil winding 78.
Furthermore, limit switch 68 must also be closed in order to
maintain contact relay 62 in an energized condition.
Also provided in the first electrical circuit is a
normally closed contact switch 72 operable in response to
energization of timing element 73 of timing device 74; element
73 and switch 72 being in parallel with contact relay coil 66.
In operation, upon closing of the normally open limit
switch 68 electrical energy is supplied to coil 66 thereby
actuating contact relay 62 closing the normally open contact
switch 56, energizing coil 78, and energizing timing element 73.
Timing element 73, after a preselected period of time, times out,
opening normally closed timing swltch 72. Opening contact
switch 72 de-energizes solenoid 14 through coil 78.
The second electrical control circuit includes the
main control switch 50 situated to closed positions 52 and 54
and electrical coil 78 and electrlcal coil 60 whlch supplies
electrical energy for the operation of the solenoids 14 and 12,
respectively. Thus, when the main control switch 50 is in the
closed positions at 52 and 54, solenoids 12 and 14 are operable
to provide fluid to the fluid cylinder 4, as discussed previously.
In the first electrical control circuit, the normally
open limit switch 68 is operable in response to the movement of
transversely extending arm 80 which is fixedly attached to the
connecting rod 84, connection rod 84 being disposed between and
fixedly attached to the damper assembly 2 at one end and the
piston 82 at the other for slideable movement through and in
fluid tight relation~with an opening in housing 4. Movement
of arm 80 against and in contacting relationship with the limit
switch contacting arm 81 actuates the limit switch 68 to a
closed position thereby energizing the first electrical control
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06~747~3 ~
circuit as discussed previously.
In the ~igure the damper blade 92 is shown in a closed
position in fluid tight relationship with seal 93 which surrounds
orifice 86 and plate 87. Blade 92 is held in position and 9up-
ported by support frame 85 and transversel~ extending rod 84 con-
- necting blade 92 to piston 82 within cylinder 4. Cylinder 4 is
generally a pneumatic or hydraulic cylinder actuated, as descrlb-
ed previously, by co~trol valve 6 and supported by support
frame 85 outside of the fluid passageway. A cylindrical projec-
tion 90 is attached on the orifice side of damper blade 92 to
provide a fluid passageway of constant cross sectional area
during a preselected portion of the stroke of the damper blade
92. This can be seen from-the dashed lines in the Figure.
During a préselected period of the damper blade~stroke cylindri-
cal projection 90 is passed through orifice 86 thereby defining
an annular;opening between the sidewalls and orifice 86. Also,
as can be seen from the Figure,-during initial stages of opening
of the damper assembly 2, damper blade 92 will be moved upwardly
from its fluid tight position on the seal 93. When this happens,
cylindrical projection 90 remains in juxtaposition with orifice
86 and a constant flow of fluid will be allowed to pass through
damper assembly 2 between the annular space defined between the
cylindrical projection 90 and the plate defining orifice 86.
Cylindrical projection 90 therefore acts as a buffer which in
effect provides for a smooth transition, for example, cloth
filter bags are being returned onstream after cleaning. In
normal operation, for example, with the baghouse including a
plurallty of cloth filter bags, the amount of initial opening o~f
the orifice 86 is only one or two inches before the contact arm
81 is contacted by the transversely extending arm 80 whi-ch stops
the movement of the damper assembly 2. It is further realized
that in close control of the damper blade away from the orifice
.
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86 a cylindrical portion 90 is not necessary.
It i9 reaIized that the damper assembly may take on
other shapes and structures, such as those described in U.S.
Patent No. 3,752,439. However, it is noted that in the utili-
zation of the damper assembly 2, as previously describedr a
variable orifice is defined during the upper movement of the
damper assembly 2. The varying orifice is then stopped at a
p~eselected distance or partially open position, in relation
to the opening 86 in wall 87. The`preselected damper assembly
2 remains in this partially open position for actuating means
: becomes operable and forces the damper assembly 2 to its fully
open position.
It will be realized that vàrious changes may be made
to the specific embodiment shown and described without departing
from the scope and principals of the present invention.
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