FIELD OF INVENTION:
The present invention relates to an improved tungsten inert gas (TIG)
welding torch for deep bore and narrow region welding in valve bodies. More
particularly, the invention relates to a welding torch which gives good visibility of
hard facing for welder and which improves quality of the weld overlay and
productivity by minimizing the defect.
BACKGROUND OF THE INVENTION:
Technical requirement was the valve body materials are to be hard faced
with stellite materials by using the old conventional TIG torch. The valve body
contains essential components like penstock, seat ring, pressure seal plug, jet
cage etc. Also some more critical location of the valve body undergoes rotary
motion by other components. This rotary motion on the alloy valve body will
cause abrasive corrosive erosion and cracks effects. To eliminate wear and tear
and reduce thereby increasing the life of the valve body by adding strength
. through stellite, this facing is done on the valve body.
These critical locations are located in the narrow and deeper region of the
valve body. At present conventional TIG torches are used for stellite laying and
hard facing in these smaller diameter and deeper region. The diameter of the
conventional TIG torches is big and the length of the torch is so short. So, the
laying and hard facing of the stellite material in narrow path was very critical.
Because of the smaller diameter and deeper region of the location to be hard
faced, welders found it difficult to lay the stellite without defects.
The defects occurred on the job because the welders were not getting
clear visibility of the narrow locations as the conventional TIG torch head

diameter was bigger and obstructing the vision of the welders. Also, as the
handle length of conventional TIG torch is small the welders were extending the
length of the torch using axe wooden sticks at the end. But this method of
extension arrangement gets damaged or distorted during welding at the deepest
• region and a sound weld could not be possible. More start and stop were
required for giving a sound weld overlay. This called for a longer cycle time. Also,
more defects occurred during welding in the above method. So, there is a need
to design and develop a new torch.
In our planned design of the deep bore TIG torch, the dimension of the
torch head diameter has been minimized and the length is also extended long so
that it will be very easy to work in narrow cavities at deeper depths. It is easy to
lay and hard face the stellite material inside the deep holes. Holes to a minimum
of 45mm and to a maximum depth of 650mm regions can be hard faced. By
, using this torch there are several components being hard faced such as
penstock, seat ring, pressure seal plug, jet cage etc.
These components are hard faced by the stellite material to avoid
corrosion, erosion, abrasives and increase the strength of the material by which
the life of the component is also increased. So, replacing of these components is
not often necessary and the life time of the valve body is increased. Hence, the
production rate is also increased.
KATO AKIRA (CN201632398) indicated the utility model relates to a TIG
(Tungsten Inert Gas) welding gun with a compact structure. The TIG welding
gun comprises a welding gun head; the welding gun head is connected with a
conductive tip; a tungsten rod is arranged in the conductive tip; a nozzle is

arranged outside the conductive tip; an end part of the tungsten rod exposes
outside the conductive tip and the nozzle; and a built-in insulating cap is
arranged at the top of the welding gun head. According to the TIG welding gun
provided by the utility model, the length of the top of the welding gun head is
reduced by adopting the built-in insulating cap, the tungsten rod, the conductive
tip and the nozzle are connected with one another in a layer-by-layer sleeving
manner and are then directly connected with the welding gun head, and the
length of the body of the welding gun is shortened on the whole, so that the TIG
welding gun with the compact structure can handle with welding tasks in various
narrow spaces and gaps.
HUNG DEREK YU-FUNG (WO2012082836) indicated in the Embodiments of a
tungsten inert gas (TIG) welding torch with an improved air cooled handle is
provided. The welding torch includes a body, a cable assembly, and a torch
head, handle placed over the body and the cable assembly the handle may
feature a curved end designed to fit near the torch head without contacting the
torch head, providing a closer gripping point to allow greater control of the torch.
In addition, the handle is spaced from the body and the cable assembly to form
an air space within the handle through which air may flow to cool the handle.
OBJECTS OF THE INVENTION:
Therefore, it is an object of the invention to propose an improved
tungsten inert gas (TIG) welding torch for deep bore and narrow region welding
in valve bodies which is able to provide good visibility of the weld region
facilitating the welder to have better manipulation of the torch resulting sound
weld.

Another object of the invention is to propose an improved tungsten inert
gas (TIG) welding torch for deep bore and narrow region welding in valve bodies
which provides accessibility and good visibility to those regions which is not
possible with the existing TIG welding torch for deep bore and narrow region
welding in valve bodies and thus to facilitate the welder to have better
manipulation of the torch to result sound weld.
A still another object of the invention is to propose an improved tungsten
inert gas (TIG) welding torch for deep bore and narrow region welding in valve
bodies which provides a low weight TIG welding torch for reducing the fatigue of
the welder.
BRIEF DESCRIPTION OF ACCOMPANYING DRAWING:
Fig. 1 : Shows a TTG Torch for smaller diameter and deeper region hard
facing overlay according to the invention.
DETAILED DESCRIPTION OF A PREFERRED EMBODIMENT OF THE
INVENTION:
As shown in figure 1, the invented torch handle (1) end comprises a hose
with a copper tube for power and water (2), a copper tube for argon gas (3) and
another copper tube for return water (4). All these three tubes brazed in the
same location for ensuring repair less and leak less conductivity. The overall
diameter of these three tube lines is reduced using reducer disc (5) with three
holes. A brass tube with rubber bush over it is used as guide to connect these

three tubes to the reducer disc. The rubber bush grips the handle rigidly by
press fit. Through the other end of the reducer disc three copper tubes are
further extended with smaller diameter tubes for increasing the length of the
torch using junction copper tubes (6) and brazing for further reduction in the
overall diameter of the tubes and are inserted into the smaller reducer disc (7)
with three holes. The tubes which cross the smaller reducer disc are gently
twisted (8) to a rope shape coiling extension such that the overall diameter of
the torch is further reduced and any required length is attained up to the TIG
welding head (9) to enter into very smaller diameter and deepest region of the
welding spot. This doubly increases the cooling effect of the welding torch.
These three vital copper tubes of the torch are covered with glass wool,
asbestos rope dipped in high ratio sodium silicate liquid for enhancing the cooling
effect of the torch during welding of hard facing overlay which emits out high
temperature and done with preheating.
The cooling effect is further preserved using cooper tubes cut into equal
horizontal halves. The copper halves are safe guarded using glass wool, asbestos
rope dipped in high ratio sodium silicate over it and glass wool insulating bush
which takes care of the total safety of the torch with highest cooling effect.
Ceramic power, Iron powder blended in low ratio sodium silicate is used in
between the cooper tube ends for strengthening the torch rigidity during
handling.

The newly designed TIG welding torch head (9) for deep bore and narrow
region welding in Valve bodies is a small diameter torch head (9) and copper
tubes (2, 3 & 4) are connected through nut and Nipple (5, 7 & 10) to reduce the
diameter of the torch which provides accessibility to those regions which is not
possible with the help of ordinary TIG welding torches. With this torch (9) a good
visibility of the weld region is obtained, thereby facilitating the welder to have
better manipulation of the torch which in turn results in sound weld. It uses
ceramic pack and cover for insulation (11) to give low weight TIG welding torch
which reduces the fatigue of the welder and enables the welder to continuously
weld for a longer time.

WE CLAIM
1. An improved tungsten inert gas (TIG) welding torch for deep bore and
narrow region welding in valve bodies comprising;
a torch handle (1) comprises of a hose;
a copper tube for power and water (2) a copper tube for argon gas (3)
and a copper tube for return water (4) disposed in the hose;
characterized in that,
the said three tubes (2,3,4) brazed in the same location for ensuring
repair less and leak less conductivity when a reducer disc (5) having three holes
is disposed for reducing the overall diameter of those said three tube lines
(2,3,4) being guided by a brass tube with rubber bush over it for connecting
these said three tubes to the reducer disc (5) where the rubber bush is disposed
for gripping the handle rigidly by press fit wherein the small diameter tubes are
disposed from the other end of the reducer disc (5) for further extending the
said tubes for increasing the length of the torch by disposed junction copper
tubes (6) when reduced diameter of tubes brazed in the junction and inserted
into the smaller reducer disc (7) having three holes when the smaller diameter
tubes crossing the reducing disc (7) forms a twisted (8) rope shape coiling
extension such that the overall diameter of the torch is further reduced and
required length is attained up to the TIG welding head (9) for entering into very
small diameter and deepest region of the welding spot.
2. The improved TIG welding torch as claimed in claim i, wherein the said
three copper tubes (2,3,4) of the torch are covered with glass wool, asbestos

rope dipped in high ratio sodium silicate liquid for enhancing the cooling effect of
the torch during welding of hard facing overlay.
3. The improved TIG welding torch as claimed in claim 1, wherein ceramic
powder, iron powder blended in low ratio sodium silicate is disposed in between
the copper tubes end for strengthening the torch rigidity during handling.

ABSTRACT

The present invention relates to a welding torch for good visibility of hard
facing for welder, quality of the weld overlay and improved productivity by
minimizing the defect comprising a invented torch handle (1) end comprises a
hose with a copper tube for power and water (2), a copper tube for argon gas
(3) and another copper tube for return water (4). All these three tubes brazed in
the same location for ensuring repair less and leak less conductivity. The overall
diameter of these three tube lines is reduced using reducer disc (5) with three
holes. A brass tube with rubber bush over it is used as guide to connect these
three tubes to the reducer disc. The rubber bush grips the handle rigidly by press
fit. From the other end of the reducer disc three copper tubes are further
extended with smaller diameter tubes for increasing the length of the torch using
junction copper tubes (6) and brazing for further reduction in the overall
diameter of the torch and are inserted into the smaller reducer disc (7) with
three holes. The tubes which cross the smaller reducer disc are gently twisted
(8) to a rope shape coiling extension such that the overall diameter of the torch
is further reduced and any required length is attained up to the TIG welding
head (9) to enter into very smaller diameter and deepest region of the welding
spot. This doubly increases the cooling effect of the welding torch.