Claims:WE CLAIM:
1. An apparatus for cutting excess material of stubs of headers in high pressure boilers comprising a band saw blade (1) placed between two rollers (2), each of which is held by a guide bar (3), wherein a jaw (4) is provided so as to place the blade according to the stub diameter and space between the stubs.

2. The apparatus for cutting excess material of stubs of headers in high pressure boilers as claimed in claim 1, wherein said jaw is mounted between two plate member (P’) resting against another plate (P) secured thereto, and the jaw, free end of which is in touch with the center of the respective roller (2).

3. The apparatus for cutting excess material of stubs of headers in high pressure boilers as claimed in claim 2, wherein the another plate (P) can be pushed forward and backward by means of moving screw (8) accommodated in screw holder (H).

4. The apparatus for cutting excess material of stubs of headers in high pressure boilers as claimed in any of the preceding claims, wherein the rollers (2) are supported with the help of longitudinal members (L) connected to safe guard (9) for the band saw blade (1), in which the safe guard (9) is located on both sides of said screw (8).

5. The apparatus for cutting excess material of stubs of headers in high pressure boilers as claimed in any of the preceding claims, wherein two handles are provided including band saw machine handle (10) to hold rear side of the apparatus with one hand and handle (5) for holding front side of the apparatus with other hand.

6. The apparatus for cutting excess material of stubs of headers in high pressure boilers as claimed in any of the preceding claims, wherein the rear handle (10) is connected to body of motor (6) of band saw unit which gives drive to the blade upon operation.

7. The apparatus for cutting excess material of stubs of headers in high pressure boilers as claimed in any of the preceding claims, wherein a motor (6) with handle (10) is placed on safe guard (7) for the motor (6).

8. The apparatus for cutting excess material of stubs of headers in high pressure boilers as claimed in claim 7, wherein the safe guard (7) is positioned next to the screw holder (H).

9. The apparatus for cutting excess material of stubs of headers in high pressure boilers as claimed in any of the preceding claims, wherein a coolant bottle (11) is provided to supply coolant for the blade during operation of the apparatus.

10. The apparatus for cutting excess material of stubs of headers in high pressure boilers as claimed in any of the preceding claims involves two operations, thereby substantial saving in time and power consumption.
, Description:An apparatus for cutting excess material of stubs of headers in high pressure boilers
FIELD OF INVENTION
[001] This invention is related to an apparatus for cutting excess material of stubs of headers in high pressure boilers. The headers are welded and heat treated headers in high pressure boilers.

[002] More particularly the invention relates to an apparatus for excess length cutting of stubs in a process of edge preparation of stubs of welded and heat treated headers following hydraulic test in high pressure boilers.

BACKGROUND OF THE INVENTION

[003] During manufacturing of components like super heater headers, water wall headers, re-heater headers, economizer headers and ring headers it is used to deliver steam to a transverse chamber including a number of pipes at different places in the high pressure boilers for power generation, wherein the outside diameter of the header pipes selected in a range from 219.1 millimeter to 864 millimeter with a thickness varying from 32 millimeter to 120 millimeter. The length of the header pipe is in the order of 6 meter to 24 meter. The material grade is of low alloy steels, of high alloy steels (grade 91) and carbon steel. During welding of the stubs on the header pipes along the length, the stubs generally get-distorted. After this welding headers are to be stress-relieved by incorporating those in the furnace and heating up to 700 degree Celsius. During this process of stress-relieving, the header also get distorted. The process of correcting this distortion is called bow correction. This
bow correction is to be carried out by placing the header pipe in a goose-neck hydraulic pressing machine.

[004] The weight of the header assembly may be from 3 tons to 32 tons depending on the size of the header and hence those headers are transported to the pressing machine for bow correction through electrically operated crane called as EOT crane. Thereafter, the stubs are aligned. After pressing and aligning, fillet welds are tested with (Non Destructive Examination) NDE- 100% MPI (Magnetic Particle Inspection) and then headers are subjected to hydraulic test to ensure leak free fillets. After hydraulic testing, heights of the stubs are checked and excess length is marked and removed at drilling m/c and ends are chamfered. The removal of excess length (40mm) of stubs with the welded dummy material takes more time as it involves lot of operations i.e 4 operations.

[005] In order to simplify this process specially developed adjustable cutting machine has been introduced by the present invention for excess length material cutting up to dummy i.e 25mm. with the available excess length of 15 mm only. Now removal of this minimum excess length (15mm) involves less operations i.e two operations which leads to finish of the job quickly.

OBJECTS OF THE INVENTION

[006] An object of the invention is to propose an apparatus for cutting excess material of stubs of headers in high pressure boilers which eliminates number of operations, thereby saving time.

[007] Another object of the invention is to propose an apparatus for cutting excess material of stubs of headers in high pressure boilers which results in increase of the output.

[008] Still another object of the present invention is to provide an apparatus for cutting excess material of stubs of headers in high pressure boilers which is simple in construction.

[009] Yet another object of the present invention is to provide an apparatus for cutting excess material of stubs of headers in high pressure boilers which eliminates the amount of rework including dummy blockage inside the stubs.

[010] Further object of the present invention is to provide an apparatus for cutting excess material of stubs of headers in high pressure boilers which allows drastic saving in power consumption.

SUMMARY OF THE INVENTION

[011] Accordingly, there is provided an apparatus for cutting of excess material of stubs during a process of bow correction of welded and heat treated headers in high pressure boilers. The apparatus comprises a band saw blade with which the excess material can be cut by placing on the stub. The blade can be slided around the rollers to get continuous movement until complete material cutting. The moving screw is used for forward and backward movement. An adjustable jaw is employed so as to place the blade as per the stub diameter and the available space between the stubs. There is a provision of two guide bars in order to hold the rollers without sliding. When the apparatus is switched on, band saw motor drives the blade to give required performance and the coolant bottle supplies coolant for the blade.

[012] Further, the invention can be summarized as follows:

[013] An apparatus for cutting excess material of stubs of headers in high pressure boilers comprising a band saw blade (1) placed between two rollers (2), adjacent to which a guide roller (3) is provided, wherein a jaw (4) is provided so as to place the blade according to the stub diameter and space between the stubs.

[014] Said jaw (4) is mounted between two plate member (P’) resting against another plate (P) secured to said two plate member (P).

[015] The another plate (P) can be pushed forward and backward by means of moving screw (8) accommodated in screw holder (H).

[016] The rollers (2) are supported with the help of longitudinal members (L) connected to safe guard (9) for the band saw blade on both sides of said screw (8).

[017] Two handles are provided including band saw machine handle (10) to hold rear side of the apparatus with one hand and handle (5) for holding front side of the apparatus with other hand.

[018] The rear handle (10) is connected to body of motor (6) of band saw unit which gives drive to the blade upon operation.

[019] A motor (6) with handle (10) is placed on safe guard (7) for the motor.

[020] The safe guard (7) is positioned next to the screw holder (H).

[021] A coolant bottle is provided which supplies coolant for the blade during operation of the apparatus.

[022] The invention involves two operations, thereby saving time.

[023] By this proposed invention, the time taken is only 202 minutes instead of 320 minutes by the current method i.e cycle time reduction is 37% and output is increased by 50%. Further, the present invention leads to huge saving in power consumption.

BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS

[024] Further objects and advantages of this invention will be more apparent from the ensuing description when read in conjunction with the accompanying drawings of the exemplary embodiments and wherein:-

Fig. 1 shows: Three dimensional view of an apparatus for cutting excess material of stubs of headers in high pressure boilers according to present invention.
Fig. 2 Shows: An isometric view of an apparatus for cutting excess material of stubs of headers in high pressure boilers in accordance with present invention.
Fig. 3 Shows: Working of present invention.
DETAIL DESCRIPTION OF THE PRESENT INVENTION WITH REFERENCE TO THE ACCOMPANYING DRAWINGS OF PREFERRED EMBODIMENTS

[025] The instant invention is pertinent to a technology in respect of an apparatus for cutting excess material of stubs of headers in high pressure boilers.

[026] Now, reference may be made to fig. 1 and 2. The apparatus comprising of a band saw blade (1) for cutting excess material of stubs of welded and heat treated headers in high pressure boilers.

[027] There is provision of two rollers (2) on both sides of said blade (1), which make the blade to move slowly without sliding. The blade can be slided around the rollers (2) so as to get continuous movement until complete material cutting.

[028] Further, a guide bar (3) is provided for each of the two rollers (2) adjacent thereto. The two guide bars (3) hold said rollers (2) without sliding.

[029] In addition to the above, an adjustable jaw (4) is employed so as to place the blade according to the stub diameter and available space between the stubs. Said jaw is mounted between two plate members (P’) resting against another plate (P) being secured thereto. The jaw, free end of which is in touch with the center of the respective roller (2) as illustrated in fig. 1. The plate (P) can be pushed forward and backward by means of moving screw (8). The screw is accommodated in a screw holder (H).

[030] The rollers (2) are supported with the help of longitudinal members (L) connected to safe guard (9) for band saw blade. The safe guard (9) is located on both sides of the screw (8).

[031] In conjunction with the above, there is provision of two handles (5, 10) at the front and rear. Said handles include band saw machine handle (10) to hold rear side of the apparatus with one hand and another handle (5) for holding front side of the apparatus with other hand in order to perform cutting. The rear handle (10) is connected to body of motor (6) of band saw unit which gives drive to the blade upon operation.

[032] Also, there are two safe guards (7, 9) wherein one (7) is meant for band saw motor (6) and the other (9) for band saw blade (1) to operate the apparatus safety.

[033] The motor (6) with handle (10) are placed on said safe guard (7) for motor.

[034] Also, a coolant bottle (11) is provided which supplies coolant for the blade during operation of the apparatus for cutting excess material of header stubs (12) as best seen in fig. 3.

[035] The above discussed apparatus involves only two operations as compared to four operations of known art for cutting of excess material of stubs. Thus, it results in time saving.

[036] It will be understood by those within the art that, in general, terms used herein, and especially in the appended claims (e.g., bodies of the appended claims) are generally intended as “open” terms (e.g., the term “including” should be interpreted as “including but not limited to,” the term “having” should be interpreted as “having at least,” the term “includes” should be interpreted as “includes but is not limited to,” etc.). It will be further understood by those within the art that if a specific number of an introduced claim recitation is intended, such an intent will be explicitly recited in the claim, and in the absence of such recitation no such intent is present. For example, as an aid to understanding, the following appended claims may contain usage of the introductory phrases “at least one” and “one or more” to introduce claim recitations. However, the use of such phrases should not be construed to imply that the introduction of a claim recitation by the indefinite articles “a” or “an” limits any particulars claim containing such introduced claim recitation to inventions containing only one such recitation, even when the same claim includes the introductory phrases “one or more” or “at least one” and indefinite articles such as “a” or “an” (e.g., “a” and/or “an” should typically be interpreted to mean “at least one” or “one or more”); the same holds true for the use of definite articles used to introduce claim recitations. In addition, even if a specific number of an introduced claim recitation is explicitly recited, those skilled in the art will recognize that such recitation should typically be interpreted to mean at least the recited number (e.g., the bare recitation of “two recitations,” without other modifiers, typically means at least two recitations, or two or more recitations). Furthermore, in those instances where a convention analogues to “at least one of A, B and C, etc.” is used, in general such a construction is intended in the sense one having skill in the art would understand the convention (e.g., “a system having at least one of A, B and C” would include but not be limited to systems that have A alone, B alone, C alone, A and B together, A and C together, B and C together, and/or A, B, and C together, etc.). In those instances, where a convention analogous to “at least one of A, B, or C, etc.” is used, in general such a construction is intended in the sense one having skill in the art would understand the convention (e.g., “a system having at least one of A, B, or C” would include but not be limited to systems that have A alone, B alone, C alone, A and B together, A and C together, B and C together, and/or A, B, and C together, etc.). It will be further understood by those within the art that virtually any disjunctive word and/or phrase presenting two or more alternative terms, whether in the description, claims, or drawings, should be understood to contemplate the possibilities of including one of the terms, either of the terms, or both terms. For example, the phrase “A or B” will be understood to include the possibilities of “A” or “B” or “A and B”.

[037] It is to be noted that the present invention is susceptible to modifications, adaptations and changes by those skilled in the art. Such variant embodiments employing the concepts and features of this invention are intended to be within the scope of the present invention, which is further set forth under the following claims:-