BACKGROUND OF THE INVENTION
The present invention relates to a flexible hose system for air preheater cleaning device.
The present invention particularly relates to rotary regenerative heat exchangers generally used as air preheaters and more particularly to a flexible hose system for air preheater cleaning device moving across the air preheater rotor which is adapted to clean with different medium and at various pressure. A rotary regenerative air preheater transfers heat from the flue gas leaving boiler to the entering combustion air through regenerative heat transfer surface in a rotor which turns continuously through the gas and air streams.
Soot or other related materials from the flue gases tend to deposit over a period of time on the heat transfer surface of the rotor of a rotary regenerative air preheater. As these deposits build up, the flow paths for the air and flue gas become blocked and the heat transfer capacity is reduced. Therefore, it is common for these air preheaters to include devices for blowing air or steam at high velocities into the rotor to dislodge the deposits.
A typical cleaner or soot blower for a rotary regenerative air preheater employs a swing arm mounted for rotation through a set of angle or arc with one or more nozzles at the end which blow the soot blowing medium (air or steam) into the rotor as the rotor turns and as the swing arm rotates through the arc. The soot blower is normally mounted on the cold end of the rotor, which is outlet end for the flue gas, but may be mounted as required in either the air or gas duct and either on the cold end or the hot end.
SUMMARY OF THE INVENTION
The present invention is directed to stainless steel flexible hose system for air preheater cleaning device adapted to supply different cleaning mediums at various pressures to the nozzle unit at the end of the swing arm specifically including high pressure water. More specifically, the stainless steel flexible hose is used in the swing arm soot blowers in place barco swivel ball joint to discharge the different cleaning mediums and in particular to discharge the high pressure water through a plurality of high pressure nozzles. The plurality of high pressure nozzles are aligned at an angle with respect to the swing arm whereby they are generally aligned with the heat exchange plates and tangential to the rotor at the outside of
the swing and at an angle to the heat exchange plates and the radius to the rotor at the inside of the swing. The barco swivel ball joint is used to connect the steam pipe line and the cleaning device assembly - swing arm, so that there will be no leakage in the steam path during operation. The swinging angle is in the range of 37° to 45°. Barco Swivel ball joint with swing arm soot blowers has been disclosed in USP6065528. The barco swivel ball joint used in the cleaning device is costlier. As an innovative set up, the stainless steel flexible hose system can be used in place of barco swivel ball joint as an alternative in the cleaning device.
Thus the present invention is provided with an improved flexible hose system for air preheater cleaning device which comprises a speed reducer, a drive motor, a worm gear box, said speed reducer being connected with said drive motor through a coupling, the other end of said speed reducer being connected to said worm gear box through a love joy coupling, said speed reducer, drive motor and the gear box being mounted on a support base, which support base being fixed on a mounting bracket, said worm shaft from said worm gear box being connected with a swivel head through a lever arm and an eccentric pin; a stainless steel barco swivel joint being connected with said swivel header at one end and the steam inlet pipe at the other end.
In the improved flexible hose system for air preheater cleaning device, the mounting bracket is fixed with the duct wall.
In the above cleaning device the drive motor is capable of rotating said speed reducer and said worm gear box.
The worm shaft of the gear box of the air preheater cleaning device is linked with a swivel header through an eccentric pin and lever arm to oscillate the swivel header. The worm shaft is mounted on the swivel header to which the soot blower arm or lance is attached.
The soot blower employs a swing arm mechjmism which is swept across the air preheater rotor at a selectable constant angular velocity from the beginning to the end o f the sweep. The present invention is described in detail with reference to the accompanying drawings, wherein
Fig. 1 illustrates known cleaning device with barco swivel joint; and Fig.2 shows a cleaning device with SS flexible hose of this invention in the above drawings.
The swing arm soot blowers is provided with a speed reducer (2) which is connected with a drive motor (3) through a coupling (5). The other end of the speed reducer (2) is connected to the worm gear box (7) through a

lovejoy coupling (6). The said speed reducer (2), drive motor (3) and the worm gear box (7) are mounted on a support base (4). The support base (4) is fixed on a mounting bracket (1). The worm shaft from the worm gear box (7) is connected with a swivel header (10) through a lever arm (8) and an eccentric pin (9). A stainless steel barco swivel joint (11) is connected with the swivel header (10) at one end and the steam inlet pipe (12) at the other end. The mounting bracket (1) is fixed with the duct wall. During operation the drive motor (3) rotates the speed reducer (2) and the worm gear box (7). The speed is further reduced in the worm gear box (7). The worm shaft is linked with swivel header (10) through eccentric pin (9) and lever arm (8) and thereby it oscillsates the swivel header (10). The worm shaft is being mounted on the swivel header (10) to which the soot blower arm or lance is attached.
Limit switches are used to terminate the swivel of the soot blower arm at the ends of its arc of travel towards the center and outside periphery of the rotor and turn off the soot blowing medium. The soot blowing medium is passed through the pipeline, barco swivel ball joint, swing arm and the nozzle to clean the heat transfer elements.
The stainless steel flexible hose assembly consists of stainless steel hose, wire braid, fixed flange and floating flange. The annular corrugated
hose body made up of stainless steel provides the flexibility and pressure tight core of the assembly. When pressure is applied, unbraided hose tends to elongate axially. To restrain this an external layer of stainless steel wire is provided on the hose. The braid is necessary to prevent elongation and to make the eissembly pressure resistant. Some times two or even three layers of braiding are provided for high pressure applications. The braiding is highly flexible arid follows the movement of the hose. The braiding is normally manufactured in high tensile SS 304 wire. The end connections are TIG welded or brazed. The one end of the flexible hose have fixed flange and the other end of the hose have floating flange.
The stainless steel flexible hose system has many advantages over the known barco swivel ball joint. The stainless steel flexible hose have high physical strength combined with light weight, suitable for wide range of temperature, good corrosion resistance, absorbs vibration and noise from connected parts, compensates for thermal expansion or contraction of piping, connects mis-aligned rigid piping, connects moving parts of equipment and a flexible and quick option for rigid piping in difficult locations. The stainless steel flexible hose had been procured, installed and tested in the airpreheater cleaning devices at various sites. The performance of the flexible hoses was observed and found satisfactory.

WE CLAIM;
1. An improved flexible hose system for air preheater cleaning device which comprises a speed reducer (2), a drive motor (3), a worm gear box (7), said speed reducer (2) being connected with said drive motor (3) through a coupling (5), the other end of said speed reducer (2) being connected to said worm gear box (7) through a love joy coupling (6), said speed reducer (2), drive motor (3) and the gear box (7) being mounted on a support base (4), which support base (4) being fixed on a mounting bracket (1), said worm shaft from said worm gear box (7) being connected with a swivel head (10) through a lever arm (8) and an eccentric pin (9); a stainless steel barco swivel joint (11) being connected with said swivel header (10) at one end and a steam inlet pipe (12) at the other end.
2. An improved flexible hose system as claimed in Claim 1 wherein said mounting bracket (1) is fixed with the duct wall.
3. An improved flexible hose system as claimed in Claim 1 or 2 wherein said drive motor (3) is capable of rotating said speed reducer (2) and said worm gear box (7).
4. An improved flexible hose system as claimed in any one of the preceding claims wherein said worm shaft is linked with said swivel header (10) through an eccentric pin (9) and lever arm (8) to oscillate the swievel header (10).
5. An improved flexible hose system as claimed in Claim 4 wherein said arm shaft is mounted on the swievel header (10) to which the soot blower arm or lance is attached.
6. An improved flexible hose system for air preheater cleaning device substantially as herein described and as illustrated in the accompanying drawings.