Title of Invention	A DEVICE AND A METHOD FOR REAMING A TAPER PIN HOLE IN THE JOINT PLANE OF INNER GUIDE PLATE OF A DIFFUSER OF A TURBINE
Abstract	A device for reaming a taper pin hole in the joint plane of inner guide plate of a diffuser of a turbine consists of a stem (3) having threads at the both ends of length for fixing to the body at one end and to a sliding block (4) at the other. The sliding block (4) has a slot for adjustment of the stem (3) for alignment of the reamer (8) with the hole. The block (4) has a threaded hole to fix a pressure screw (5) which applies constant pressure to the shank of the reamer during reaming operation. A ratchet handle (6) holds the reamer and imparts rotational motion for reaming the hole. A method for reaming this taper pin hole comprises of aligning the pin hole (9), reamer (8) and a pressure screw (5) by adjusting the stem (3) in the slot of a sliding bloclk. The reamer is held by a ratchet handle (6) that imparts rotational motion to the reamer by rotating it manually while the pressure screw (5) applies constant pressure to the shank of the reamer till the taper pin hole is reamed to the required size and finish.

Title of Invention

A DEVICE AND A METHOD FOR REAMING A TAPER PIN HOLE IN THE JOINT PLANE OF INNER GUIDE PLATE OF A DIFFUSER OF A TURBINE

Abstract

A device for reaming a taper pin hole in the joint plane of inner guide plate of a diffuser of a turbine consists of a stem (3) having threads at the both ends of length for fixing to the body at one end and to a sliding block (4) at the other. The sliding block (4) has a slot for adjustment of the stem (3) for alignment of the reamer (8) with the hole. The block (4) has a threaded hole to fix a pressure screw (5) which applies constant pressure to the shank of the reamer during reaming operation. A ratchet handle (6) holds the reamer and imparts rotational motion for reaming the hole. A method for reaming this taper pin hole comprises of aligning the pin hole (9), reamer (8) and a pressure screw (5) by adjusting the stem (3) in the slot of a sliding bloclk. The reamer is held by a ratchet handle (6) that imparts rotational motion to the reamer by rotating it manually while the pressure screw (5) applies constant pressure to the shank of the reamer till the taper pin hole is reamed to the required size and finish.

Full Text	FIELD OF INVENTION The present invention relates to a device and method for reaming a taper pin hole in the joint plane of inner guide plate of a diffuser of a turbine. BACKGROUND OF THE INVENTION Inner guide plate of a diffuser in the range of 210 MW to 500 MW, is one of the main component of low pressure turbine. One main turbine consists of three turbines modules, viz. high pressure turbine, intermediate pressure turbine and low pressure turbine. The low pressure turbine, like other turbines, is manufactured by fabricating it in two parts when each part is being machined separately. Facing operation of the' Joint plane face by piano milling both halves is carried out keeping necessary machining allowances. Then holes on upper half are drilled. Holes on parting flange of lower half are transfer marked from holes drilled in upper half and subsequently drilling and tapping operation are carried out. The upper half and lower half is then joined with fasteners. Reaming of taper pin holes at joint plane are then done. Dowel pins are fitted in these reamed holes to avoid dislocation of two halves during subsequent finish machining on a vertical boring machine. Because of this aspect, reamed holes are very important from quality andj accuracy of size point of view. The location of taper pin holes aie in such a position that it is not possible to carry out drilling and reaming operation on any conventional machine. As this part is of complicated design and joint plane is inside the outer ring and outside the inner ring of inner guide plate, the reaming operation has to be done manually by applying pressure screw technology. In the prior art, a temporary threaded piece is welded on the inner guide plate body and pressure screw is used to apply pressure during reaming using ratchet handle manually. As this temporary threaded piece is to be welded on job, it has to be shifted to another section/area for welding that results in delays. Moreover, it is very difficult to align the axis of the threaded piece and pressure screw with joint plane taper pin holes as there is no flexibility available for adjustment after welding. Hence, aligning of pin hole, reamer and pressure screw in one straight line is very difficult to achieve resulting variation in pin hole size that required enlarged or deviated taper pin. It means new pins are required to be made suiting to this holes. This obviously affects the interchangeability. Surface finish is also found to be poor. The whole process takes lot of time. Finally the welded piece is required to be removed and subsequent fettling and grinding is required to be done. Accordingly there exists a need to find a method of reaming the taper pin holes which can eliminates the disadvantages of prior art. OBJECTS OF THE INVENTION It is therefore an object of the invention to propose a device and method for reaming taper pin holes at joint plane of inner guide plate of a diffuser of a turbine which is capable of aligning the pin hole, reamer and pressure screw in a straight line. Another object of invention is to propose a device and method for reaming taper pin holes at joint plane of inner guide plate of a diffuser of a turbine which is capable of producing accurate ream«d holes for required size of dowels. A still another object of the invention is to propose a device and method for reaming taper pin holes at joint plane of inner guide plate of a diffuser of a turbine which reduces the cycle time of operation. BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS Fig.l- Isometric view of Inner guide plate of diffuser showing reaming operation with invented devics. Fig.2- shows the invented device and its parts. Fig.3- shows the inner guide plate of diffuser. DETAILED DESCRIPTION OF A PREFERRED EMBODIMENT OF THE INVENTION Inner guide plate (1) of a diffuser in the range of 210 MW to 500 MW of a low pressure turbine is manufactured by fabrication in two parts (A,B) which are then machined to make those parts ready for assembling together by fasteners (2). First, the joint planes (C) of the two fabricated unit are faced on a piano milling as per marking by distributing machining allowances uniformly. Three holes on upper half (12) for insertion of a cylindrical stem and for reaming and for fastening are made. These holes are then marked on the lower half (13) after clamping the two parts properly by the fastener so that markings are not disturbed. Similar drill holes are then made on the lower half (13). Tapping of one hole for example with M48 is th«2n done. Joining of upper half and lower half is done using for example M48 fastener (2) in the tapped hole. As shown in fig.2 the device (2a) consists of a stem (:$) for example of 75 mm dia milled flat for a length for example 200 mm to avoid fouling of the ratchet handle (6) during rotation manually. The total length of the stem (3) for example is 525 mm having reduced thread dia (10,11) i:or example of M20 and M36 threads at the two ends of the length of the stem (3). The sliding block (4) is for example of length 160 mm, width 60 mm and height 30 mm has a slot of width for example 22 mm and length 100 mm to accommodate the threaded dia of the stem (3) and such that the threaded dia has room to be manoevured for adjustment along the length of the slot. The stem of the device is then fixed in one of the other two holes as shown in fig.l by for example M36 nut and washer. The other end of the stem (3) is fixed with a sliding block (4) assembled in slot (14). The slot (14) is for adjustment in alignmen: of pin hole (9), reamer (8) and pressure screw (5). The sliding block (4) has a threaded hole (13) above the slot (14) for the provision of a pressure screw (5). This sliding block (4) can be aligned with pin hole axis very easily and manual reaming can be done with a reamer (8) and ratchet handle (6) while pressure screw (5) fixed in the threaded hole (15) giving a constant pressure on the reamer provides a constant support and alignment. As shown in fig (2) the device (2a) has a built in sliding block (4) that can be adjusted as per requirement and p'oper alignment of the reamer (8) with the pressure screw (5) and the hole (9) to be reamed is ensured. Since the taper pin hole location (9), reamer (8) and pressure screw (5) are all in one line, an accurate hole (9) with required quality and surface finish is achieved. This process gives no scope for any devicition in hole size and shape. Time and labour taken by this process is very less compared to earlier one. Earlier the two units used to be joined by fasteners while in the present invention, using a stem (3) in place of one of the fasteners alorg with sliding block (4) has enhanced the quality of the hand reaming operaton. The cylindrical stem (3) and the sliding block (4) has given the process much rigidity and scope of adjustment for alignment. After the reamed hole being produced as per drawing, the taper dowel pins are fitted in the hole to make the unit ready for final finish machining on a vertical boring machine. As the device (2a) is clamped with the job, it gives high degree of rigidity. For producing the reamed taper pin hole (9), the device (2a) is placed in position with the stem (3) locked on the body at the joint face by a nut (7) in one side and clamped with the sliding block (4) on the other side after passing through a slot (14) on the block (4). The reamer (8) is placed on the drilled hole (9) to be reamed ensuring the correct alignment with the pressure screw (5) engaged with the reamer when a continuous pressure is applied on the shank of the reamer (8) during reaming operation providing a constant support to the reamer (8), The rachet handle (6) holds the reamer (8) and is rotated to give a rotational motion to the reamer (8) inside the drilled hole (9) to produce finally the reamed taper pin hole of required size and finish. WE CLAIM 1. A device (2a) for reaming a taper pin hole (9) in the joint plane (6) of inner guide plate (1) of a diffuser of a turbine, comprising: at least one cylindrical stem (3) having threaded ends (10,11) for fixing with the body (12,13) at one end by nut (7) and with a sliding block (4) at the other end; the said sliding block (4) having a slot (14) at the middle and a threaded hole (15) above the slot (14), a pressure screw fixed in the threaded hole of the block (4); characterized in that the fixat on of stem (3) provides rigidity, adjustment and alignment. 2. A method for reaming a taper pin hole (9) in the joint plane (C) of inner guide plate (1) of a diffuser of a turbine comprising the steps of: a ratchet handle (6) is attached to the reamer (8); the reamer (8) is positioned h the drilled hole; the stem (3) is adjusted in the slot (14) of the sliding block (4) to make the pin hole (9), the reamer (8) and the pressure screw (5) properly aligned; a pressure screw (5) fixed in the threaded hole (15) is engaged with the shank of the reamer (8) which applies constant pressure on the reamer to maintain alignment of the reamer (8) with the pin hole; the ratchet handle (6) is rotated to provide a rotational motion to the reamer (8) to produce the taper pin hole. OF L.S.DAVAR & CO. APPLICANTS' AGENT 3. A method for reaming a taper pin hole (9) in the joint plane (C) of inner guide plate (1) of a diffuser of a turbine as claimed in claim 2 wherein adjustment of alignment is carried out by adjusting the stem (3) in the slot (14) of the sliding block (4). A device for reaming a taper pin hole in the joint plane of inner guide plate of a diffuser of a turbine consists of a stem (3) having threads at the both ends of length for fixing to the body at one end and to a sliding block (4) at the other. The sliding block (4) has a slot for adjustment of the stem (3) for alignment of the reamer (8) with the hole. The block (4) has a threaded hole to fix a pressure screw (5) which applies constant pressure to the shank of the reamer during reaming operation. A ratchet handle (6) holds the reamer and imparts rotational motion for reaming the hole. A method for reaming this taper pin hole comprises of aligning the pin hole (9), reamer (8) and a pressure screw (5) by adjusting the stem (3) in the slot of a sliding bloclk. The reamer is held by a ratchet handle (6) that imparts rotational motion to the reamer by rotating it manually while the pressure screw (5) applies constant pressure to the shank of the reamer till the taper pin hole is reamed to the required size and finish.

Full Text

FIELD OF INVENTION
The present invention relates to a device and method for reaming a taper pin
hole in the joint plane of inner guide plate of a diffuser of a turbine.
BACKGROUND OF THE INVENTION
Inner guide plate of a diffuser in the range of 210 MW to 500 MW, is one of the
main component of low pressure turbine. One main turbine consists of three
turbines modules, viz. high pressure turbine, intermediate pressure turbine and
low pressure turbine. The low pressure turbine, like other turbines, is
manufactured by fabricating it in two parts when each part is being machined
separately. Facing operation of the' Joint plane face by piano milling both halves
is carried out keeping necessary machining allowances. Then holes on upper half
are drilled. Holes on parting flange of lower half are transfer marked from holes
drilled in upper half and subsequently drilling and tapping operation are carried
out. The upper half and lower half is then joined with fasteners. Reaming of
taper pin holes at joint plane are then done. Dowel pins are fitted in these
reamed holes to avoid dislocation of two halves during subsequent finish
machining on a vertical boring machine. Because of this aspect, reamed holes
are very important from quality andj accuracy of size point of view.
The location of taper pin holes aie in such a position that it is not possible to
carry out drilling and reaming operation on any conventional machine. As this
part is of complicated design and joint plane is inside the outer ring and outside

the inner ring of inner guide plate, the reaming operation has to be done
manually by applying pressure screw technology.
In the prior art, a temporary threaded piece is welded on the inner guide plate
body and pressure screw is used to apply pressure during reaming using ratchet
handle manually. As this temporary threaded piece is to be welded on job, it has
to be shifted to another section/area for welding that results in delays. Moreover,
it is very difficult to align the axis of the threaded piece and pressure screw with
joint plane taper pin holes as there is no flexibility available for adjustment after
welding. Hence, aligning of pin hole, reamer and pressure screw in one straight
line is very difficult to achieve resulting variation in pin hole size that required
enlarged or deviated taper pin. It means new pins are required to be made
suiting to this holes. This obviously affects the interchangeability. Surface finish
is also found to be poor. The whole process takes lot of time. Finally the welded
piece is required to be removed and subsequent fettling and grinding is required
to be done.
Accordingly there exists a need to find a method of reaming the taper pin holes
which can eliminates the disadvantages of prior art.
OBJECTS OF THE INVENTION
It is therefore an object of the invention to propose a device and method for
reaming taper pin holes at joint plane of inner guide plate of a diffuser of a
turbine which is capable of aligning the pin hole, reamer and pressure screw in a
straight line.

Another object of invention is to propose a device and method for reaming taper
pin holes at joint plane of inner guide plate of a diffuser of a turbine which is
capable of producing accurate ream«d holes for required size of dowels.
A still another object of the invention is to propose a device and method for
reaming taper pin holes at joint plane of inner guide plate of a diffuser of a
turbine which reduces the cycle time of operation.
BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS
Fig.l- Isometric view of Inner guide plate of diffuser showing reaming
operation with invented devics.
Fig.2- shows the invented device and its parts.
Fig.3- shows the inner guide plate of diffuser.
DETAILED DESCRIPTION OF A PREFERRED EMBODIMENT OF THE
INVENTION
Inner guide plate (1) of a diffuser in the range of 210 MW to 500 MW of a low
pressure turbine is manufactured by fabrication in two parts (A,B) which are then
machined to make those parts ready for assembling together by fasteners (2).
First, the joint planes (C) of the two fabricated unit are faced on a piano milling
as per marking by distributing machining allowances uniformly. Three holes on
upper half (12) for insertion of a cylindrical stem and for reaming and for
fastening are made. These holes are then marked on the lower half (13) after

clamping the two parts properly by the fastener so that markings are not
disturbed. Similar drill holes are then made on the lower half (13). Tapping of
one hole for example with M48 is th«2n done. Joining of upper half and lower half
is done using for example M48 fastener (2) in the tapped hole. As shown in fig.2
the device (2a) consists of a stem (:$) for example of 75 mm dia milled flat for a
length for example 200 mm to avoid fouling of the ratchet handle (6) during
rotation manually. The total length of the stem (3) for example is 525 mm
having reduced thread dia (10,11) i:or example of M20 and M36 threads at the
two ends of the length of the stem (3). The sliding block (4) is for example of
length 160 mm, width 60 mm and height 30 mm has a slot of width for example
22 mm and length 100 mm to accommodate the threaded dia of the stem (3)
and such that the threaded dia has room to be manoevured for adjustment along
the length of the slot. The stem of the device is then fixed in one of the other
two holes as shown in fig.l by for example M36 nut and washer. The other end
of the stem (3) is fixed with a sliding block (4) assembled in slot (14). The slot
(14) is for adjustment in alignmen: of pin hole (9), reamer (8) and pressure
screw (5). The sliding block (4) has a threaded hole (13) above the slot (14) for
the provision of a pressure screw (5). This sliding block (4) can be aligned with
pin hole axis very easily and manual reaming can be done with a reamer (8) and
ratchet handle (6) while pressure screw (5) fixed in the threaded hole (15) giving
a constant pressure on the reamer provides a constant support and alignment.
As shown in fig (2) the device (2a) has a built in sliding block (4) that can be
adjusted as per requirement and p'oper alignment of the reamer (8) with the
pressure screw (5) and the hole (9) to be reamed is ensured. Since the taper pin
hole location (9), reamer (8) and pressure screw (5) are all in one line, an
accurate hole (9) with required quality and surface finish is achieved. This
process gives no scope for any devicition in hole size and shape. Time and labour
taken by this process is very less compared to earlier one. Earlier the two units
used to be joined by fasteners while in the present invention, using a stem (3) in
place of one of the fasteners alorg with sliding block (4) has enhanced the

quality of the hand reaming operaton. The cylindrical stem (3) and the sliding
block (4) has given the process much rigidity and scope of adjustment for
alignment. After the reamed hole being produced as per drawing, the taper
dowel pins are fitted in the hole to make the unit ready for final finish machining
on a vertical boring machine. As the device (2a) is clamped with the job, it gives
high degree of rigidity. For producing the reamed taper pin hole (9), the device
(2a) is placed in position with the stem (3) locked on the body at the joint face
by a nut (7) in one side and clamped with the sliding block (4) on the other side
after passing through a slot (14) on the block (4). The reamer (8) is placed on
the drilled hole (9) to be reamed ensuring the correct alignment with the
pressure screw (5) engaged with the reamer when a continuous pressure is
applied on the shank of the reamer (8) during reaming operation providing a
constant support to the reamer (8), The rachet handle (6) holds the reamer (8)
and is rotated to give a rotational motion to the reamer (8) inside the drilled hole
(9) to produce finally the reamed taper pin hole of required size and finish.

WE CLAIM
1. A device (2a) for reaming a taper pin hole (9) in the joint plane (6) of
inner guide plate (1) of a diffuser of a turbine, comprising:
at least one cylindrical stem (3) having threaded ends (10,11) for fixing
with the body (12,13) at one end by nut (7) and with a sliding block (4) at
the other end;
the said sliding block (4) having a slot (14) at the middle and a threaded
hole (15) above the slot (14),
a pressure screw fixed in the threaded hole of the block (4);
characterized in that the fixat on of stem (3) provides rigidity, adjustment
and alignment.
2. A method for reaming a taper pin hole (9) in the joint plane (C) of inner
guide plate (1) of a diffuser of a turbine comprising the steps of:
a ratchet handle (6) is attached to the reamer (8);
the reamer (8) is positioned h the drilled hole;
the stem (3) is adjusted in the slot (14) of the sliding block (4) to make
the pin hole (9), the reamer (8) and the pressure screw (5) properly
aligned;
a pressure screw (5) fixed in the threaded hole (15) is engaged with the
shank of the reamer (8) which applies constant pressure on the reamer to
maintain alignment of the reamer (8) with the pin hole;
the ratchet handle (6) is rotated to provide a rotational motion to the
reamer (8) to produce the taper pin hole.

OF L.S.DAVAR & CO.
APPLICANTS' AGENT
3. A method for reaming a taper pin hole (9) in the joint plane (C) of inner
guide plate (1) of a diffuser of a turbine as claimed in claim 2 wherein
adjustment of alignment is carried out by adjusting the stem (3) in the
slot (14) of the sliding block (4).

A device for reaming a taper pin hole in the joint plane of inner guide plate of a diffuser of a turbine consists of a stem (3) having threads at the both ends of length for fixing to the body at one end and to a sliding block (4) at the other. The sliding block (4) has a slot for adjustment of the stem (3) for alignment of
the reamer (8) with the hole. The block (4) has a threaded hole to fix a pressure screw (5) which applies constant pressure to the shank of the reamer during reaming operation. A ratchet handle (6) holds the reamer and imparts rotational motion for reaming the hole. A method for reaming this taper pin hole comprises of aligning the pin hole (9), reamer (8) and a pressure screw (5) by adjusting the stem (3) in the slot of a sliding bloclk. The reamer is held by a ratchet handle (6) that imparts rotational motion to the reamer by rotating it manually while the pressure screw (5) applies constant pressure to the shank of the reamer till the
taper pin hole is reamed to the required size and finish.

Documents:

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Patent Number

271523

Indian Patent Application Number

2155/KOL/2008

PG Journal Number

09/2016

Publication Date

26-Feb-2016

Grant Date

24-Feb-2016

Date of Filing

15-Dec-2008

Name of Patentee

BHARAT HEAVY ELECTRICALS LIMITED

Applicant Address

REGIONAL OPERATIONS DIVISION (ROD), PLOT NO: 9/1, DJBLOCK 3RD FLOOR, KARUNAMOYEE, SALT LAKE CITY, KOLKATA-700091, HAVING ITS REGISTERED OFFICE AT BHEL HOUSE, SIRI FORT, NEW DELHI-110049

Inventors:

#	Inventor's Name	Inventor's Address
1	ALOK KUMAR	HEEP BHEL HARIDWAR
2	RAJENDRA SINGH	HEEP BHEL HARIDWAR

PCT International Classification Number

F01K7/00

PCT International Application Number

N/A

PCT International Filing date

PCT Conventions:

#	PCT Application Number	Date of Convention	Priority Country
1			NA