|Title of Invention||
"A DEVICE FOR REDUCTION OF WEAR IN BENDS CARRYING PARTICULATE FLOW."
|Abstract||The invention, relates to a device for re of wear in bends carrying particulate In a coal based thermal power station the particulated air with the pulverised coal 1a carried from the pulverizers to the boiler through at hetwork of piping. Indian coal are rich in abressive alfa quartz which causes extensive wear in the pipes particularly at bends. The bends are repaired or replaced at frequent intervals causing lower efficiency. The existing method of expensive ceramic lining at bends may extend the life of the pipe bonds a little longer. But soon after the ceramic llning wears out the pipe start wearing very fast, The present invention uses a device by providing two bend sayer plates at the inner surface of the bend, one at entry and the other befone the exit of the bend pipes. The bend saver plates, are made of mild steel and are tack or stitch welded they wear out. The main purpose of the bend saver plate is to project the inner surface of the bendipe from wear.|
|Full Text||This invention relates to a device for reduction of wear in bends carrying particulate flow.
In a coal based thermal power station the particulatrd air with the pulverised coal is carried from the pulverizers to the boiler t furnace through a long network of piping to various coal burners. On entering the bend the solid particles separate from the carrier air and impinge on the inner surface of the outer wall due to effect of inertia and centrifugal force and lead to wear of the outer wall. With the curvature of the bend continuing, the impingement and the drag of the particles continue on the rest of the inner surface of the outer wall of the bend and causing the wear. The wear is negligible in the straight pipes as the particles travel with air in a stream-lined fashion parallel to the pipe wall.
There are disadvantages associated with the existing system of particulate flow such, coal and air to the boiler.
One of the main disadvantages with the existing system is that. The coal, particularly the Indian coal is rich in abrassive alfa-quartr This not only leads to excessive wear of pulveriser components but also the bends in the piping lying between the pulverizers and the coal burners.
Another disadvantage is with the existing system is that due to excessive wear the pipe bends are subjected to
frequent puncture in the large radius side walls leading to loss of pressure, air, coal dust and energy in addition to causing air pollution in the neighbourhood.
Yet another disadvantage with the exihting system is that frequent repairs/replacements of such worn out pipes bends has always been a major constraints to tfficlent functioning of the Power Plant.
A further disadvantage with the existing system is that to minimise the problem of repair or replacements, ceramic lining is provided on the inner surface of the bends. Providing ceramic lining inside the bend is expensive. These also wear out little time later than bare pipe exposing the metal of the bends to wear faster.
Therefore, the main object of the present invention is to provide a simple and effective device to minimise the wear of the bend pipes due to particulate flow.
Yet a further disadvantage with the existing system is that the bends are repaired at the damaged parts by welding plates in patches and replace it when no further repair can done*
An object of the present invention/is to provide a device comprising multifunctional bend saver plates so that the wear of the bend is minimum.
Another object of the present invention is to provide bend saver plates which could be sacrificial by using ordinary mild steel or made to last for a longer period by using right type of wear resistance steel.
Yet another object of the present invention is to provide these saver plates locally and not at type ptire pipe
at bend portion so as to keep the initial
to minimum and replacement easier and economical.
A further object of the present invention is to provide the saver plates which can be made easily removable with tack or stitch welding.
According to the present invention there provided a device for reduction of wear in bendi carrying particulate flow comprising, two bend saver plates provided at the inner surface of the'outer wall of the bend pipe characterised in that the first, bend saver plate is fixed at the.begining of the bend pipe in the direction of particulate flow and the second bend saver plate is fixed at the end portion of the bend pipe and at the trailing edge of the inner surface
of the first & second bend saver plate is provided with a profile to deflect the particles away from the inner surface and the leading edges of the said,first, & second bend saver plates are profiled &, bent in-a manner to provide a sheet of Air jet behind the plates at the end close to the inner surface of the outec,wall of the bend pipe. The nature of the invention Its objective and further advantages residing in the same will be apparent from the following description made with reference to non-limiting exipmplary embodiments of the invention represented in the accompanying drawings.
FIG 1. Shows an elevation of the bend pipe with the bend saver plates.
FIG. 2. View 'AA' of the bend pipe showing the portion and details of the bend saver plates.
In accordance with the present invention, the device comprises two bend saver plates/ provided
in a location of maximum wear zone of the'-bend pipe. The basic! bend mentioned is generally made of mild steel and fixed inside the bend pipe by tack or stitch welding so that they can bo easily replaced. The existing practice of providing expensive ceramic lining is thus avoided.
The device is reconomical as these plates
are relatively small in size and made of mild teel
The first bend saver plate/is fixed at the . '
begining of the bend pipe/ in the direction of
particulate flow. The second saver plate/ ll fixed of the bend pipe.
The trailing edges of both the bend saver
plates/are provided with a profile/so that "the1
are released in such a way that they do not iming.
on the bend inner surface for a long distance down-steam. At the leading edges/ of both the bend saver
plates/and are profiled and bent/ in a manner so as
to provide a sheet of air jet behing the plate at the end close to the inner surface of tho outter wall, which acts as cushion against any impinging particles, protecting a further length of the outer wall surface.
The life of the bend pipe with the bend
saver plates increase - manifold. This device can easily be used in all types of sections of Pipe bends where similar problems are encountered. The device is simple to adapt and inexpensive to implement.
The invention described hereinabove is in relation to a non-limiting embodiment and as defined by the accompanying claims.
WE CLAIM :
1. A device for reduction of wear in bends carrying particulate flow comprising two bend saver plate provided
at the inner surface of the outer wall of the bend pipe characterised in that the first bend saver plate (1) is fixed at the begining of the bend pipe (5) in the direction of Particulate flow and the second bend saver plate (2) is fixed at the end portion of the bend pipe (5) and at the trailing edges of the inner surface of the first & second bend saver plates (1,2) is provided with a profile (3) to deflect the particles away from the inner surface and the leading edges of the said first, & lecon'd . . bend saver plates (1,2) are profiled & boot (4) in i manner to provide a sheet of Air Jet behind the pittas (1,2) at the end close to the inner surface of the outer wall of the bend Pipe (5)
2. The device as claimed in claim 1, wherein the
leading edges of the two bend saver plates (1,2)'ar* provided
with a profile and bent (4) away from the innef surface 6f the bends pipe (5) to form cushion of sheet of air jet behind the plate (1,2).
3. The device as claimed in claim 1, wherein the
trailing edges two bend saver plates (1,2) are provided
with a profile (3) to deflect the particles away from the
walls of the downstream straight pipe.
4. The device as claimed in claim 1, wherein the
two bend saver plates (1,2) made of mild steel are tack or
stitch welded for easy replacement.
5. The device as claimed in claim 1 & 4, wherein
the two bend saver plates 0,2} are of special s wear resistance steel.
6. A device for reduction of wear in bends carrying participate flow as hereinabove described and, illustrated.
|Indian Patent Application Number||561/DEL/1997|
|PG Journal Number||10/2008|
|Date of Filing||05-Mar-1997|
|Name of Patentee||BHARAT HEAVY ELECTRICALS LIMITED,|
|Applicant Address||BHEL HOUSE, SIRIFORT, NEW DELHI 110 049, INDIA|
|PCT International Classification Number||B21D 7/25|
|PCT International Application Number||N/A|
|PCT International Filing date|