FIELD OF THE INVENTION
The present invention relates to a method of manufacturing electrically operated
relief valve. In particular, the invention relates to a method of connecting main
base and inlet neck in the manufacturing of Electromatic Relief Valve. More
particularly, the invention relates to a method of joining main base and inlet neck
of electromatic relief valves by an improved welding nozzle in a semi-automatic
submerged arc welding process.
BACKGROUND OF THE INVENTION
Manufacturing process of Electronic relief valve includes joining of two parts
namely main base and Inlet neck by Shielded metal arc welding process takes
about 24 hours to complete the job. The welder fatigue is further increased for
prolonged cycle time. The welder welds the job manually while the job rotates.
Rotation speed of the job is set by the welder as per his convenience. The slag
removal is also a tiring job in this process. There is no rotational arrangement for
deeper penetration in the narrow groove. All these prior art disadvantages call
for an alternate method of welding the main base and inlet neck of the
electromatic relief valves automatically. The Electromatic Relief valve is used in
boilers to purge the super heater and a header, to reduce the possibility of
damaging the spring-loaded safety valve seats or turbine equipment.

OBJECTS OF THE INVENTION
It is therefore an object of the present invention to propose a method of joining
main base and inlet neck of electromatic relief valves by an improved welding
nozzle in a semi-automatic submerged arc welding process.
A further object of the present invention is to propose a method of joining main
base and inlet neck of electromatic relief valves by an improved welding nozzle in
a semi-automatic submerged arc welding process, in which a tilting mechanism is
adapted in the SAW machine for deeper penetration.
SUMMARY OF THE INVENTION
Accordingly, the main base and inlet neck of the electromatic relief valve are
fitted on a conventional fixture to carry out the root welding, These two parts are
lifted and positioned to a tiltable positioner disposed on the SAW machine. A
welding nozzle is designed such that a maximum weld groove width of 7 mm
can be welded, that means, the groove is very narrow with one side having 15o
taper and another side Oo with vertical. The welding nozzle is fitted to a welding
torch of the SAW machine by threaded connection. Now the wire spool is rotated
and through a wire feed system, a consumable wire is fed to the narrow groove.
Butt joint of the main base and inlet neck is possible through the improved
welding nozzle. Upto normal V-groove, the job axis is kept horizontal with ground
in IG position and material is deposited layer by layer. The slag comes out by
itself as the weld area cools down slightly during rotation of the job. But for
tapered portion, welding of the job keeping the same in horizontal

position is difficult as the material may flow, so the tiltable hole positioned is
tilted by 15o so that tapered portion can be assumed as V-groove and welding is
carried out. On the SAW machine, the job welding is completed in one shift.
BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS
Figure 1 shows a cross sectional view of connecting the two components namely
Main base and Inlet neck.
Figure 2 shows an improved welding nozzle according to the invention.
Figure 3 shows another embodiment of the improved welding nozzle.
Figure 4 shows a SAW machine fitted with a work piece for welding the main
base and inlet neck using the improved welding nozzle of the invention.
DETAILED DESCRIPTION OF A PREFERRED EMBODIMENT OF THE
INVENTION
Referring to figure 4, main base (01) and Inlet neck (02) of the valve, are tack
welded to form a welded assembly which is taken to the positioned (05) and
kept nearer to the SAW machine (05).

Depending upon the parameters of relief valve, an improved welding nozzle is
fitted to the welding torch (06) of the SAW-machine. The wire spool (08) is
rotated through the wire feeder system (09) of the machine to feed the
consumable wire (10) to the weld groove.
Butt joint of the main base (01) and the neck (02) through the welding nozzle
(03) / (04) is carried out to the joining material layer by layer and the slag comes
out by itself as the weld area cools down slightly as the job rotates. The
positioned (5) is tilted by 15o so that the tapered portion of the groove can be
assumed as a V-Groove and welding is completed in one setting.
EXPERIMENTAL DATE DATA FOR THE DEVELOPMENT OF NOZZLE
The male thread in the nozzle is machined to suit the female thread of the
welding torch. The inner diameter of the nozzle is made to suit the wire
diameter.
1. Nozzle developed for welding Main base – 7501:-
Length of the Nozzle: 120 ; OD of cylindrical portion – 12 mm
Taper angle and length: 10o with taper length 70 mm
2. Nozzle developed for welding Main base – 7520 :

Total length of Nozzle: 135 mm ; OD of upper portion of Nozzle – 12 mm
OD of lower portion of Nozzle: 8 mm ; Length of lower portion of Nozzle: -
80 mm
The above dimensions are derived by experiments and the trial was completed
successfully.

WE CLAIM :
The method of welding of narrow groove of main base and inlet neck in the
manufacturing of electromatic relief valve comprises of following steps:-
- fixing the tack welded assembly of Main base (01) and Inlet neck (02) in
the SAW machine (07) provided with a tiltable hole positioned;
- feeding a consumable wire (10) to the narrow groove butt joint through
the improved welding nozzle (03/04);
wherein the consumable wire is made to pass through a wire feed system
(09) from a wire spool (08) at constant feed rate;
- depositing the consumable material layer by layer up to a normal V
groove, followed by tilting of the positioned by 15o for the tapered portion
of the groove and the welding is carried out;

wherein the male thread of the nozzle is machined to match the female thread of
the welding torch and wherein the inner diameter of the nozzle is made to
correspond to the wire diameter.