FIELD OF THE INVENTION
This present invention relates to a purging apparatus for welding of thin walled
Titanium tube in intricate position.
BACKGROUND OF THE INVENTION
Welding of titanium joints requires high level of cleanliness, is to be conducted in
a location free from atmosphere air. These process parameters are ensured by
providing a purging arrangement to the joint region just before, during, and just
after the welding process. Purging requires that all regions ambient to the weld
joint are filled with inert gas such that the atmosphere is free from contaminants.
Sometimes due to configuration of the weld joint and accessibility constraints, it
is not possible to provide effective purging to the weld joint which results in poor
quality of weld joints. As the joints in such areas are prone to in-service cracks
and other types of serious malfunctions, a substantial number of joints are either
rejected in totality, or call for change in the configuration of the joint to enable
quality-welding.
OBJECTS OF THE INVENTION
It is therefore an object of the invention to propose a purging apparatus
assembly to prevent contamination of weld joints during welding of thin-welded
titanium tubes in intricate positions.
Another object of the invention is to propose a purging apparatus assembly to
prevent contamination of weld joints during welding of thin-welded titanium
tubes in intricate positions, which provides uniform cooling to maintain colour of
the weld joint.
A further object of the invention is to propose a purging apparatus assembly to
prevent contamination of weld joints during welding of thin-welded titanium
tubes in intricate positions, which produces weld joints to meet RT-quality
requirements.
SUMMARY OF THE INVENTION
Accordingly, there is provided a purging apparatus assembly comprising a
plurality of unions. A coil of Titanium tube is inserted into the unions and fillet
welding is done over the unions. The mandatory requirement of the process is
that welding is to be carried out under closed purged atmosphere. To meet the
mandatory requirement, our novel circular purging gadget has been invented.
The invention described herein consists of an apparatus to direct the purging gas
to the weld joint uniformly to ensure that mist formation is caused in the weld
zone and there is no traces of undesirable atmospheric elements. The
compactness of the apparatus ensures that it can be employed in intricate
locations having 60mm gap in between the tubes.
The apparatus consists of an enclosure to which a source of inert gas is
connected and an outlet which includes perforated sheet, and at least six layers
of mesh in the order of course, medium and fine to ensure uniform distribution
of the inert gas. The apparatus includes a shutter means retractable to a desired
levels as per convenience of the welder such that a good quality weld joint is
obtained.
BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWING
The proposed invention will be better understood by the following description
with reference to the accompanying drawing.
Figure 1 - shows a purging of thin walled titanium tube weld joint in intricate
configurations according to the invention.
DETAILED DESCRIPTION OF A PREFERRED EMBODIMENT OF THE
INVENTION
As shown in figure - 1, an inlet (1) connected to an inert gas source is disposed
of the welding zone which directs inert gas on the tope side to the weld zone on
the bottom side. A locking plate (2) supporting a Base Plate (3) and a cover ring
(4), together constitutes a purging enclosures (5). A thin walled Titanium tube
(6) which is to be welded over union is covered by the Split enclosure (5) such
that the opening and closure of the enclosure can be controlled to suit welding
configuration. A plurality of mesh / Perforated sheets (7) allows mist formation in
the weld zone. To provide a back purging to the weld zone, a purging apparatus
(8) is provided through the tube. During welding, a torch purging (11) is also
provided. The Torch purging, back purging and purging through the tube all put
together form a global purging (10) which prevents contamination during the
thin walled Titanium tube welding.
WE CLAIM
1. A purging apparatus assembly to prevent contamination of weld joints
during welding of thin-welded titanium tubes in intricate positions,
comprising:
- a titanium tube for welding over a plurality of unions on at least two
collectors;
- a split type purging enclosure having a lock plate, a base plate, and a
cover ring;
- an inert gas source with an outlet means disposed around the welding
zone such that the outlet means remains located on the top; side so as
direct inert gas towards the bottom side;
- the tube with unions covered by the said split type enclosure;
- a plurality of mesh / perforated sheets in an order of course, medium, and
fine disposed at the outlet means so as to uniformly distribute the inert
gas during welding; and
- a shutter means configured on the enclosure and being retractable to
desired levels allowing the operator to implement the welding to produce
a good quality of joint.

ABSTRACT

The invention relates to a purging apparatus assembly to prevent contamination
of weld joints during welding of thin-welded titanium tubes in intricate positions,
comprising a titanium tube for welding over a plurality of unions on at least two
collectors; a split type purging enclosure having a lock plate, a base plate, and a
cover ring; an inert gas source with an outlet means disposed around the
welding zone such that the outlet means remains located on the top; side so as
direct inert gas towards the bottom side; the tube with unions covered by the
said split type enclosure; a plurality of mesh / perforated sheets in an order of
course, medium, and fine disposed at the outlet means so as to uniformly
distribute the inert gas during welding; and a shutter means configured on the
enclosure and being retractable to desired levels allowing the operator to
implement the welding to produce a good quality of joint.