FIELD OF INVENTION
The present invention relates to a device for cleaning the fireside deposits of
fossil fuel fired boilers. The device hereinafter is called the soot blower.
BACKGROUND OF THE INVENTION
In fossil fuel-fired boilers, the residue of combustion sticks to the heat transfer
surfaces of boiler and forms as a bad conductor of heat, affecting the heat
transfer. It has direct implication on the efficiency of the boiler. A device for
clearing such deposits generally known as soot blower is used to remove such
deposits and improve the boiler efficiency. The soot blowing is done by steam or
air as the blowing medium.
Soot blower mainly consists of a housing, which holds the bottom angle, and top
angle, and which holds a rack. At the rear end of the housing, a Valve head assy
is fixed. The gearbox assy with two output shaft, one along the axis and the
other across the axis, is held on both the traverse track with proper meshing of
the pinion with the rack. The traveling carriage is fixed to the gearbox. A lance
assy is fixed with the traveling carriage and moves over the feed pipe with
suitable packings for leak proof operation of the blower. The lance has two
nozzles at the end. The steam passes through the head assembly of the Soot
Blower Valve (SBV) at a recommended pressure for blowing. The SBV Head assy
has a provision for the pressure adjustment. The steam jet from the nozzles
strikes the heat transfer surfaces and dislodges the deposits.

A further object of invention is to propose a device for clearing the fireside
deposits of the fossil fuel fired boilers, in which a valve adjustment mechanism is
implemented to enable on line soot blowing pressure adjustments.
A still further object of the invention is to propose a device for clearing the
fireside deposits of the fossil-fuel fired boilers, which enables balanced loading of
the gearbox and carriage assembly on both the axes of the device.
SUMMARY OF INVENTION
Accordingly, there is provided an improved device for cleaning the fireside
deposits of fossil-fuel fired boilers, comprising a gearbox assembly having two
output shaft, a lateral output shaft out of said two out put shaft provides a
traverse movement to a traveling carriage assembly, and an axial shaft with
sprocket for providing rotary motion to a lance assembly, a soot blower valve
(SBV) head assembly fixed to a housing assembly , for allowing ingress of steam
into the lance assembly including a feed pipe assembly, the lance assembly with
the help of nozzles impinging steam on the coils disposed on the internal wall of
the boiler to remove the deposits, the improvement is characterized in that:

US Patent no: 5,353,996- discloses a balanced design construction of a soot
blower. However, the unbalanced design as described in the patent is likely to
lead to instability including wear and tear.
US Patent nos. 5,097,564 & 4,803,959- describe soot blowers operation by
Indexing of the jet path. The indexing provision is made as an internal
arrangement of the traveling carriage assy.
US Patent no: 3,439,376- discloses soot blowers with emergency hand cranking
provisions. The emergency hand cranking provision is given with both rotary and
traverse movement with more effort.
OBJECTS OF INVENTION
It is therefore, an object of the invention is to propose a device for clearing the
fireside deposits of the fossil-fuel fired boilers, in which the indexing provision is
kept external to the traveling carriage by means of an easily removable slotted
sprocket assy.
A still another object of invention is to propose a device for clearing the fireside
deposits of the fossil-fuel fired boilers, which provides a declutch mechanism at
the gearbox output shaft resulting in emergency cranking with lesser effort.

the lateral output shaft is provided with-two pinions which are disposed
on the gear box assembly across the travel axis with at least two bearings
disposed equispacedly along the travel axis for a balanced loading,
the sprocket is configured to have a key-way extending upto 90° segment
enabling transmission of rotational movement of the lance assembly in
one direction only, and simultaneously restricting any rotation of the lance
till the sprocket completes a 90° turn, during the intervening period, a
phase-shift of the helical path of the steam jet is achieved by virtue of a
small movement of the nozzles without the rotation of the lance ,
the gear box is provided with a square-headed rotary output shaft for
emergency retract, which is achieved by a declutching mechanism in
which the rotary sprocket is disconnected to by-pass the rotary motion
and impart only a traverse motion via the square-headed rotary shaft by
using hand crank which reduces the manual efforts during emergency
retract; and
the SBV head assembly comprises a valve stem and a valve lever, the
latter being operated by a cam assembly which during the device
operation brings the valve lever down to open the valve, the valve
opening stroke is adjustable by means of an adjustment means which
enables an on-line setting of the blowing pressure.

The indexing features of the inventive soot blower enables a phase shift of the
steam jet for effective cleaning through external slotted sprocket arrangement.
The indexing mechanism is simple, open and easy for maintenance. The declutch
mechanism for the hand cranking disengages the rotary motion of the lance and
gives only traverse motion with lesser effort. The on line adjustment of the
blowing pressure for effective cleaning is done by the adjustment mechanism
while the soot blower is in operation. The arrangement of the equispaced load
taking bearings and the drive pinion gives a steady and balanced operation of
the blowers.
BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS
Fig-1. Soot blower indicating the various parts and arrangements according to
the invention
Fig-2. A sectional view of the equispaced arrangement of the drive pinion and
the equispaced load taking bearings for a balanced drive system of the soot
blower
Fig-3. A valve adjustment mechanism indicating the adjusting screw.
Fig-4. A declutch mechanism adapted for the emergency hand cranking.

DETAILED DESCRIPTION OF INVENTION
As shown in Fig.-l, the soot blower comprises a Gearbox assy (01),
a traveling carriage assy (02) a housing assy (03), a SBV head assy (04), a feed
pipe assy (05), a lance assy (06),and a bearing and yoke assy (07).
The gearbox (01) has two output shaft, one for the traverse movement and
another for rotation of the lance (06). The lateral output shaft is fixed with two
pinions (09) on either side of the gearbox (01), which will be meshing with a
rack (08) to provide the traverse movement. The rack (08) is firmly fixed by
bolting with the top angle. The axial shaft is mounted with sprocket (13), which
provides the rotary motion to the lance assy (06). The SBV Head assy (04)
admits steam into the feed pipe assy (05) and the lance assy (06). The feed pipe
external surface is smooth finished to prevent steam leakage through the
packings. The lance assy (06) is provided with two nozzles, which impinges
steam on to the coils in the boiler to remove the deposits.
The two drive pinions (09) on the gearbox assy (01) across the travel axis and
the load taking bearings are provided along the travel axis are equispaced for a
balanced loading. The significance of the design is that the reactive force due to
the pinion and the rack drives (08,09) is well balanced. This results in the steady
travel of the blower with minimal wear and tear.

Roller chains are connected to the sprocket (13) on the traveling carriage (02),
which is keyed to a TC assy spindle extension. The sprocket (13) is designed in
such a way that it has a key way made up to 90 deg segment. It enables to
transmit the rotation of the lance (06) in one direction and during reversal of
direction, there will not be any rotation of the lance (06) up to 90 deg turn of the
sprocket (13). By the time the nozzle is moved slightly without the rotation of
lance (06) , phase shift of the helical path of the steam jet is obtained. This
provision facilitates the complete cleaning of the coils. The advantage of this
arrangement is the phase shift drive is obvious and external with heavy duty
sprocket construction. The replacement and maintenance is a simple a process.
In the gear box assy (01), a square headed rotary output shaft (14) is used for
the emergency retract. For efficient retract, the rotary motion is bypassed by the
declutch mechanism. By declutching, the rotary sprocket (13) is disconnected
and only traverse motion is imparted through the square headed shaft (14) by
hand crank. The main advantage of the hand cranking is that the rotary motion
is by-passed only traverse motion is imparted which is resulting in the lesser
manual effort during the emergency retract.
The device has steam admission valve called Soot Blower Valve (SBV) Head assy
(04). This is fixed at the rear end plate of the housing assy (03). The valve lever
(11) is placed just above the valve stem (10). The valve lever (11) is operated by
a cam assy. When the blower is operated, the cam assy is activated after the
dead travel. The cam assy brings down the valve lever (11) and pushes down
the valve stem (10) so as to open the valve. The valve opening stroke can be
adjusted by the adjusting screws (12) fixed on the valve lever (11). This will
enable to set the blowing pressure as per the requirement even while the blower
is in operation.

WE CLAIM:
1. An improved device for cleaning the fireside deposits of fossil-fuel fired
boilers, comprising :
- a gearbox assembly (01) having two output shaft, a lateral output
shaft out of said two out put shaft provides a traverse movement to a
travelling carriage assembly (02), and an axial shaft with sprocket (13) for
providing rotary motion to a lance assembly (06);
-a soot blower valve (SBV) head assembly (04) fixed to a housing
assembly (03), for allowing ingress of steam into the lance assembly (06)
including a feed pipe assembly (05), the lance assembly (06) with the help of
nozzles impinging steam on the coils disposed on the internal wall of the
boiler to remove the deposits, the improvement is characterized in that:
- the lateral output shaft is provided with-two pinions (09) which are
disposed on the gear box assembly (01) across the travel axis with at
least two bearings disposed equispacedly along the travel axis for a
balanced loading,
- the sprocket (13) is configured to have a key-way extending upto 90°
segment enabling transmission of rotational movement of the lance
assembly (06) in one direction only, and simultaneously restricting any
rotation of the lance (06) till the sprocket (13) completes a 90° turn,
during the intervening period, a phase-shift of the helical path of the

steam jet is achieved by virtue of a small movement of the nozzles without the
rotation of the lance (06)
- the gear box (02) is provided with a square-headed rotary output shaft
(14) for emergency retract, which is achieved by a declutching mechanism
in which the rotary sprocket (13) is disconnected to by-pass the rotary
motion and impart only a traverse motion via the square-headed rotary
shaft (14) by using hand crank which reduces the manual efforts during
emergency retract; and
- the SBV head assembly (04) comprises a valve stem (10) and a valve
lever (11), the latter being operated by a cam assembly which during the device
operation brings the valve lever (11) down to open the valve, the valve opening
stroke is adjustable by means of an adjustment means (12) which enables an
on-line setting of the blowing pressure
2. The device as claimed in claim 1, wherein the drive pinions (09) mesh with a
rack (08) to provide the traverse motion, the rack (08) being fixed at top angle.
3. An improved device for cleaning the fireside deposits of fossil-fuel fired boilers,
as substantially described and illustrated herein with reference to the accompanying drawings.

The invention relates to an improved device for cleaning the fireside deposits of fossil-fuel fired boilers, comprising a gearbox assembly (01) having two output shaft, a lateral output shaft out of said two out put shaft provides a traverse
movement to a travelling carriage assembly (02), and an axial shaft with sprocket (13) for providing rotary motion to a lance assembly (06), a soot blower valve (SBV) head assembly (04) fixed to a housing assembly (03), for allowing
ingress of steam into the lance assembly (06) including a feed pipe assembly (05), the lance assembly (06) with the help of nozzles impinging steam on the coils disposed on the internal wall of the boiler to remove the deposits, the
improvement is the lateral output shaft is provided with-two pinions (09) which
are disposed on the gear box assembly (01) across the travel axis with at least two bearings disposed equispacedly along the travel axis for a balanced loading, the sprocket (13) is configured to have a key-way extending upto 90° segment
enabling transmission of rotational movement of the lance assembly (06) in one direction only, and simultaneously restricting any rotation of the lance (06) till the sprocket (13) completes a 90° turn, during the intervening period, a phase-
shift of the helical path of the steam jet is achieved by virtue of a small movement of the nozzles without the rotation of the lance (06) the gear box (02) is provided with a square-headed rotary output shaft (14) for emergency
retract, which is achieved by a declutching mechanism in which the rotary sprocket (13) is disconnected to by-pass the rotary motion and impart only a traverse motion via the square-headed rotary shaft (14) by using hand crank
which reduces the manual efforts during emergency retract, and the SBV head assembly (04) comprises a valve stem (10) and a valve lever (11), the latter being operated by a cam assembly which during the device operation brings the
valve lever (11) down to open the valve, the valve opening stroke is adjustable by means of an adjustment means (12) which enables an on-line setting of the blowing pressure