FIELD OF THE INVENTION:
The present invention relates to a novel device for hydrotesting of vertical
separator or more particularly to a novel method and device that utilizes a taper
thread made inside or outside of the nozzle of a vertical separator vessel of high
pressure steam generators.
BACKGROUND OF THE INVENTION:
Hydro testing is a process in which all the pressure parts are tested for strength
and leaks by pressurization of the vessel to the specified test pressure.
Conducting 100% radiography of all the weld joints assure that weld joints are
defect free but can never provide with the assurance of mechanical integrity of
a system. Hence Hydrostatic testing is the most common method employed for
testing pipes and pressure vessels. This is also to be noted that radiography or
ultrasonic inspection shall also not to be waived off if the component is to be
hydrostatically tested. Pressure tightness is tested by shutting off the supply
valve and observing whether there is a pressure loss over a period of time as
specified by the inspector or typically for 30 minutes.
Vertical separator vessel is a pressure part used for separation of steam at
startup and low load in recirculation mode. It is manufactured by welding of
nozzles (02) to a pipe (01) of OD around 0.6m. Nozzles of various diameters
ranging from Dia.260mm to Dia.450mm with thickness ranging from 50mm to
101.6mm are welded on to the vertical separator pipe whose ends are closed
with hemispherical dished ends. The nozzle and pipe sizes vary as per the MW
rating.
All the nozzle ends are welded with dummy round plates matching the ID of the
nozzle for performing hydro test of the separator vessel. The test pressure lies
from 350 to 480 bar. A conventional Hydro testing method of separator vessel
by using welded dummies is as shown in Fig.6.
Patent Application number IN908KOL2014 invention relates to a universal
device for hydro testing of differently dimensioned welded tubes/pipes
comprising at least four metal rods each having threaded portions; and one

each side is adjoined with nylon „0‟ ring at the facing of the test sample and the
side plates, wherein the side plates are provided with matching holes to hold
the extension portion of the tube sample, and wherein the threaded portions of
said rods having dimensions corresponding to that of said holes of the side
plates.
Patent Application number IN1353KOL2014 Patent relates to “a multi jack
hydraulic testing device for hydraulic testing of fan impeller blade bearing
assembly, comprising a hydraulic pump with a plurality of outlets; a plurality of
impeller blades fixed on a test bed; a plurality of isolating valves and a plurality
of pressure gauges provided on the test bed; and the plurality of outlets from
the hydraulic pump each separately connected to each of the plurality of
impeller blades via each of said plurality of valves and pressure gauges;
wherein the number of pump outlet, isolating valve, pressure gauge and
impeller segment is identical so as to substantially reduce the testing cycle of a
complete fan blade assembly. The above invention is for a different product and
does not contribute for the present invention.
But in the conventional method, the dummies are welded before the
hydrotesting and then it is removed thereafter, which results unnecessary
waste of time and energy.
Further, after performing the hydrotest, stress relieving cycle has to be
employed, which also lengthen and complicate the whole process.
Hence, there is a long-felt need to develop an innovative device and method for
hydro-testing of vertical separator vessel, which can overcome the above-
mentioned difficulties.
The present invention meets the long felt need.
SUMMARY OF THE INVENTION:
A device for hydro-testing of vertical separator comprising: a special taper
thread which is attached with the separator nozzles; a cylinder for facilitating

the guiding of piston; a central member called piston, which is seated on the
nozzles and guides in the cylinder; multiple number of O-rings provided on the
piston; a connector(10, 10a, 11) for putting the piston (6 or 6a) towards the
nozzle; characterized in that said taper thread is designed to take all the
reaction load during pressurization and thereby need of welding and complete
removal of the dummies after hydro test, is nullified.
OBJECTS OF THE INVENTION:
It is therefore, the principal object of the present invention to provide a device
for hydro-testing, which include a special taper thread and can support self-
sealing of liquid.
Another object of the present invention to provide a device for hydro-testing,
which can easily be placed on to the nozzles.
Yet another object of the present invention to provide a device for hydro-testing,
which has sufficient rigidity and stability in carrying out the hydro test.
Further object of the present invention to provide a device for hydro-testing
which is sleek and light-weight, and having a simple construction.
Another object of the present invention to provide a method for hydro-testing
which is simple yet quick.
Yet another object of the present invention to provide a method for hydro-
testing which provide a means to lock with self-acting pressure.
BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWING:
It is to be noted, however, that the appended drawings illustrate only typical
embodiments of the present subject matter and are therefore not to be
considered for limiting of its scope, for the invention may admit to other equally
effective embodiments. The detailed description is described with reference to
the accompanying figures. Some embodiments of system or methods in
accordance with embodiments of the present subject matter are now described,
by way of example, and with reference to the accompanying figures, in which:

Fig-1 illustrates the invented device assembly during hydro testing.
Fig-2 illustrates the typical invented device assembly equipped with internal
thread
Fig-3 illustrates the detailed components of the device with internal thread.
Fig-4 illustrates the typical invented device assembly equipped with external
thread.
Fig-5 illustrates the detailed components of the device with external thread.
Fig-6 illustrates a schematic representation of conventional method of
Hydrotesting with welded dummy plugs.
Fig-7 illustrates a dummy connector to be used, in place of inlet connector
when the nozzle is neither used as inlet nor for mounting pressure gauge.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS:
The present subject matter herein relates to a novel device for hydrotesting of
vertical separator in high pressure steam generators wherein welding of
dummies or flat end covers on the vessel has been eliminated.
According to an implementation of the present subject matter, two types of
special taper threads (3 or 4) are provided, one can be suited to the separator
nozzle inside diameter called the external type and another to the Nozzle
outside diameter, named internal type.
These taper threads can take care of minor ovality and scaling formed after
heat treatment of the separator vessel thus providing proper assembly. Taper
thread on cylinder (5 and 5a) acts as a reaction support while pressurizing and
does not apply force on the nozzle. The device can be employed even if a
component had “n” number of openings with various diameters.
Fig 1 illustrates the position of novel device for hydrotesting in the high
pressure steam generators.
The hydrotesting device (1) is mounted on to different nozzles (2) of separator
vessel.

Fig 2 and Fig 4 illustrates all the structural components of the device which is
equipped with internal thread (3) or external thread (4) respectively.
A taper internal type thread (3) is provided to suit the separator nozzle outside
diameter for taking reaction load during pressurization (as shown in Fig 2).
Fig 4 illustrate a taper external type thread (4), on the cylinder (5a) of the device
which is attached with the separator nozzle inside diameter.
The device again comprises a central member called piston (6 and 6a) with
atleast two holes.
It is designed in typical way to facilitate entry of pressurized fluid during hydro
in to the chamber and which in turn will pressurize the device to avoid leak.
Piston guides inside the cylinder and a connector is attached at the end.
Apart from the threads, the hydrotesting device (1) also comprising:
a cylinder (5 and 5a) for facilitating the guiding of piston (6 and 6a);
a central member called piston (6 and 6a) is seated on the nozzle and cylinder
(5 and 5a).
The devices also comprises multi number of a O-rings such as (7 and 7a), (8
and 8a), (9 and 9a) which are mounted prior to the assembly;
a connector (10 and 10a) which pushes the piston (6 and 6a) towards the nozzle
while tightening (clearly shown in Fig 3 and 5).
Fig 3 and 5 illustrates the piston which has small holes (12 and 12a) for
passing of fluid during hydro test which has eventually entered into chamber
and further moves the piston (6 and 6a) towards nozzle and resulted in leak
proof joint. Cylinder (5 and 5a) is locked to nozzle using the taper thread (3 and
4).
The piston (6 and 6a) directly touches the nozzle wall and seals with the O-
rings (7 and 7a).

Further, a dummy connector (11) is only provided (as shown in Fig 7) where
there are more than three nozzles in a separator vessel as one nozzle opening is
used for inlet of water and the second one for mounting pressure gauge.
All the O-rings (7 and 7a, 8 and 8a, 9 and 9a) are mounted prior to the
assembly. Surfaces where O-ring comes in contact are made to a surface
roughness of 0.8 to avoid O-ring failure due to roughness of the surface.
In accordance with the other embodiment of the present subject matter, the
water passes through holes because of back pressure in piston (6 and 6a)
towards the component and thereby provides better sealing.
Hence, the chance of liquid crossing the inlet connector thread which is
arrested by O-ring (9 and 9a) provided in the connector is substantially
reduced. Additional O-ring (8 and 8a) is provided arresting leak through piston
(6 and 6a) circumference.
Water is filled into the component to be hydrotested using Connector (10 or
10a) through a pump line and pressurized continuously till the rated pressure
or the pressure as prescribed by statutory codes is achieved.
Supply is cut off after the rated pressure is achieved and then holded for a
period of time generally for half an hour.
After the test, Hydrotesting device (1) is removed and further used. Thread in
the nozzles is washed out and Edge prepared.
Also connector can be used either as inlet to the component or as an inlet to
pressure gauge during hydrotesting. By this novel method, back pressure
during hydro testing also acts on piston (6and 6a) and further tightens the
sealing by pressing the piston (6 and 6a) against the component wall thus
providing self-acting pressure sealing.

WE CLAIM:
1. A device for hydro-testing of vertical separator comprising:
a special taper thread (3 or 4) which is formed in or on the separator
nozzles;
a cylinder (5 and 5a) for facilitating the guiding of piston (6 and 6a);
a central member called piston (6 and 6a), which is seated on the nozzles
and cylinder (5 and 5a);
a dummy connector (11), used in case of more than 2 nozzles in a
separator
multiple number of O-rings (7 and 7a), (8 and 8a) and (9 and 9a) provided
on the piston (6 and 6a) respectively;
a connector (10 or 10a) for putting the piston (6 or 6a) towards the
nozzle;
characterized in that said taper thread is designed to take all the reaction load
during pressurization and thereby need of welding and complete removal of the
dummies after hydro test, is nullified.
2. The device for hydro-testing of vertical separator as claimed in claim 1,
wherein the taper thread (4) is attached to the separator nozzle at the outside
diameter on the cylinder (5a).
3. The device for hydro-testing of vertical separator as claimed in claim 1,
wherein the taper thread (3) is attached to the separator nozzle inside the
diameter of the cylinder (5).
4. The device for hydro-testing of vertical separator as claimed in claim 1,
wherein the piston (6 or 6a) has small holes for passing the fluid into the
chamber and moving the piston (6 or 6a) towards nozzle.
5. The device for hydro-testing of vertical separator as claimed in claim 1,
wherein surface in contact with said O-rings (8 and 8a) has a roughness of 0.8.

6. The device for hydro-testing of vertical separator as claimed in claim 1,
wherein which further comprise dummy connectors (11) placed in the cylinder
(5 and 5a).
7. A method for hydro-testing of vertical separator comprising the steps of:
passing of water through said holes (12) into the chamber and moving
the piston (6 or 6a);
providing protection against leak of liquid by arresting with O-rings (9
and 9a), placed in the connector and other O-rings (10 and 10a) on piston (6 or
6a) circumference;
filling water into the component by using a connector and pressurizing
continuously until reaches to the rated pressure cutting off the supply after
attaining to the rated pressure.
8. The method for hydro-testing of vertical separator as claimed in claim 7,
continuous for half an hour or for the time specified by user .