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system (linkage), the damper shaft is connected by
linkage to the jackshaft. On a parallel positioning system
(linkageless), the shaft is directly coupled to the actuator
for the air damper.
The air damper mounts to the fan inlet and controls the
air flow to the fan. On low NOx burners, the air damper
is connected to the FGR adapter plate, so that the flue
gas can enter down-stream of the damper where there is
a negative pressure. If an optional silencer were used, it
would be mounted to the inlet of the air damper.
Figure B-7 Multi-blade damper
3. Burner Drawer
Figure B-8 Burner Drawer Assembly
The burner drawer contains the pilot, scanner, diffuser
and oil gun. These components are all attached to the
backplate. The burner drawer is removed as a complete
unit for adjustment and inspection. The burner drawer
slides through the windbox, head extension and into the
gas manifold. It is attached to the burner by bolting the
backplate to the windbox.
The pilot, scanner, oil gun and diffuser position can be
adjusted (in and out) by sliding the tube through the
backplate. Setscrews are used to lock these tubes into
position. The oil gun can be removed for inspection or
extended gas firing without removing the burner drawer.
Diffuser
The diffuser provides the directional control of the
combustion air for mixing and combustion stability. The
diffuser uses a combination of outer swirl air and inner
straight air. An inner ring is fastened to the diffuser in
some applications.
The JBE diffuser sits inside the head section of the
burner and is secured by one of two methods:
1) On smaller JBE(X)5 & JBE(X)7 burners with 12" and
JBE(X) Manual
Blades
Page 10
Figure B-9 Diffuser
14" heads ("J" head and "K" head respectively), the
diffuser has two straps which attach the cylindrical
portion of the diffuser to the burner head extension.
Adjustment may be made by loosening the bolts in the
slotted holes located on each side of the head extension
and then carefully sliding them forward or back. Once
desired adjustment has been achieved, re-tighten bolts
to lock it in that position.
2) On larger JBE(X)7 and JBE(X)9 burners with 16" ("L"
head) and larger, the diffuser is attached to the center
tube of the drawer assembly. Adjustment to this type of
diffuser requires loosening the setscrews that secure the
center tube position on the back of the drawer assembly.
Once loosened, carefully slide the tube forward or back
through the drawer assembly backplate. When desired
position is achieved, re-tighten setscrews on back of
drawer assembly to secure the center tube. It may be
necessary to remove the diffuser (for example if spud
changes are to be made). First, ensure that all power
to the burner has been locked out. On smaller burners,
remove the two side fasteners used for adjustment of
diffuser, then remove the side access cover on the head
extension. Once the access cover is removed, it will be
necessary to partially withdraw the drawer assembly
in order to move the diffuser back. Once the diffuser is
moved back sufficiently, it may be withdrawn sideways
through the access opening. Diffuser removal on larger
units is much the same, although there are no side bolts
through the head extension and the diffuser must be
unfastened from the center tube of the drawer assembly
before it can be withdrawn from the access opening.
When removing and re-installing the diffuser in the
JBE(X) burner, there are a few things to keep in mind.
First, the diffuser position is critical for proper firing.
Before removing or adjusting the diffuser, it is wise to
make reference marks where the diffuser position is set
(side bolts for smaller units or the large center tube on
larger units). Secondly, when re-installing a diffuser, it
is important that the scanner's sight tube be positioned
properly. The diffuser will have a larger hole which the
scanner tube must pass through by at least 1/8". Note
the hole position before removing the diffuser so that
when it is replaced, the hole will be in the correct position
and the sight tube may be placed through it. Also note
the position of the proven gas pilot with reference to the
sight tube. The tube is positioned next to the gas pilot so
that the swirl direction of the diffuser will cause the flame
of the pilot to curl in front of the scanner tube.
Section B - Components
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