Description:FORM 2
THE PATENT ACT 1970
(39 OF 1970)
&
The Patent Rules, 2003
COMPLETE SPECIFICATION
(See Section 10 and Rule 13)

1 TITLE OF THE INVENTION :
A SYSTEM OF TESTING CIRCUIT FOR HYDRAULIC TESTING OF PRESSURE VESSELS AND METHOD OF TESTING USING THE SAME.



2 APPLICANT (S)

Name : STEEL AUTHORITY OF INDIA LIMITED.

Nationality : Indian.

Address : BHILAI STEEL PLANT, BHILAI, DIST.-DURG, CHHATTISGARH
INDIA, PIN-490001.





3 PREAMBLE TO THE DESCRIPTION

COMPLETE

The following specification particularly describes the invention and the manner in which it is to be performed.

FIELD OF THE INVENTION
The present invention relates to a system of testing circuit for hydraulic testing of pressure vessels. More particularly, the present invention is directed to a modified hydraulic testing circuit for the hydro-testing of pressure vessels (hydro-pneumatic) or accumulators enabling to carry out hydraulic pressure test of the pressure vessels or accumulators with minimized man power and time, without the need for disconnecting the pressure vessel from the equipment of application and depressurizing the vessel and removing the safety valve and plugging it and again pressurizing it to test pressure before testing thereby consuming much time and manpower and down time of equipment as being done conventionally.

BACKGROUND OF THE INVENTION
In Plate Mill of Applicant’s Bhilai Steel Plant , there are twenty numbers of pressure vessels (hydro-pneumatic type ) or accumulators with capacities varying from 2000 litres to 9000 litres and with working pressure ranging from 6 kg/cm2 to 170 kg/cm2.These pressure vessels have to tested hydraulically once in every two years as per The Factories Act 1948. As per the oil requirement of actuators (hydraulic cylinders etc), pressurized oil provided by accumulator.

In the original design of pressure vessels/accumulators, there is no provision for the testing circuit for hydraulic testing of pressure vessels. It is left to the user of the vessel to get it disconnected from the equipment of application before testing (refer FIG -1). After that the vessel has to be depressurized, draining out oil and nitrogen, and its safety valve has to be removed and plugged. Later it has to be pressurized to the test pressure for testing. After completion of testing, pressure vessel has to be again depressurized for its normalization. Finally the vessel has to be restored for working by fitting the safety valve and pressurized to working pressure. The total test procedure takes about 16 hours time during which the application equipment remains inoperative causing substantial production loss.

The present invention thus targets to provide a new design and development of hydraulic testing circuit that helps in testing of pressure vessels in a simple, faster and safe manner with less down time of the equipments being connected to it. This design incorporation can be done in the new pressure vessel manufacture, fabrication and erection. It can also be retrofitted in existing pressure vessels.

OBJECTS OF THE INVENTION

The basic object of the present invention is directed to provide a system of testing circuit for hydraulic testing of pressure vessels/accumulators and a method of such pressure testing in a simple, safe and faster manner without the need for disconnecting the pressure vessel from the equipment of application thus saving lot of time and incidental costs and avoid down time of equipments.

A further object of the present invention is directed to said testing circuit for hydraulic testing of pressure vessels/accumulators without disconnecting the pressure vessel from the equipment of application whereby the elaborate tasks of the need for disconnecting the pressure vessel from the equipment of application and depressurizing the vessel and removing the safety valve and plugging it and again pressurizing it to test pressure before testing as practiced conventionally can be avoided.

A still further object of the present invention is directed to said testing circuit for hydraulic testing of pressure vessels/accumulators without disconnecting the pressure vessel from the equipment of application wherein the system is adapted to be deployed in new pressure vessel manufacture, fabrication and erection, as well as can also be retrofitted in existing pressure vessels.

A still further object of the present invention is directed to said testing circuit for hydraulic testing of pressure vessels/accumulators without disconnecting the pressure vessel from the equipment of application that helps in safer hydraulic testing of pressure vessels and causing safe work environment to the work force.

A still further object of the present invention is directed to said testing circuit for hydraulic testing of pressure vessels/accumulators without disconnecting the pressure vessel from the equipment of application that reduces the involvement of manpower and substantial saving of expenditure.

SUMMARY OF THE INVENTION
The basic aspect of the present invention is directed to a system of testing circuit for hydraulic testing of pressure vessels of accumulators comprising:
Auto shut off valve (ASV), isolation Valve (AIV1), accumulator oil Drain Valve (DV1),Nitrogen Drain Valve (NDV) connected to atmosphere and wherein the system includes :
an Isolation Valve of Nitrogen (NIV1) fitted between safety valve and accumulator;
an Oil Drain Valve (DV2);and
an additional port fitted with Valve (AP1) for facilitating testing of accumulator free of need for disconnecting said pressure vessel from equipment of application and depressurizing the vessel and removing safety valve and plugging it and again pressurizing it to test pressure before testing and avoiding related downtime and manpower.

A further aspect of the present invention is directed to said system comprising
a hydraulic circuit including said pressure vessels or Accumulator for storing and supplying pressurized oil to equipments of application including hydraulic actuators in plate mill wherein each said Accumulator is fitted with Auto-Shut Off Valve(ASV), Isolation Valve (AIV1), accumulator oil Drain Valve (DV1), Nitrogen Supply Valve (NSV), Safety Valve (SV), Nitrogen Drain Valve(NDV) connected to atmosphere, an isolation Valve Of Nitrogen (NIV1)(Class 2500) fitted between safety valve and Accumulator, an Oil Drain Valve (DV2) (Class 2500), and
an Additional Port Fitted With Valve(AP1), (Class 2500) for facilitating pressure testing of Accumulator without disconnecting from application equipment, and wherein
hydraulic pump with Relief Valve is provided to feed hydraulic oil at desired pressure to the system and accumulator; wherein in normal operation after the oil level into accumulator reaches to high working level, hydraulic pumps start unloading the Relief Valve and as per the oil requirement of Actuators ( Hydraulic Cylinders etc.), pressurized oil provided by accumulator; and as soon as the level of Accumulator goes to low working level , hydraulic Pumps again start loading the relief valve and again the pressurized oil from Pump goes to System and Accumulator upto its high working level, and this cycle repeats endlessly;

said “Accumulator” act as an energy reservoir for the system and also its level column indicators facilitates the hydraulic system to run in “auto” mode;

said “Auto-Shut Off Valve ( ASV)” is provided to protect the hydraulic system, during any power failure condition or during any oil leakage into the system; and

said “Safety Valve(SV)” is provided to protect the accumulator and its connected accessories (viz : pipe lines, nitrogen supply/drain valve etc) during any sudden pressure surge into the system.

A still further aspect of the present invention is directed to said system wherein said pressure vessels (hydro-pneumatic type ) are with capacities varying from 2000 litres to 9000 litres and with working pressure ranging from 6 kg/cm2 to 170 kg/cm2 , which need to be tested hydraulically once in every two years (as per The Factories Act 1948).

A still further aspect of the present invention is directed to said system wherein during normal working of said hydraulic system, “Auto Shut-Off Valve (ASV)”, “Isolation Valve(AIV1)” of Accumulator, “Isolation Valve(NIV1)” before “Safety Valve”, “Drain Valve(DV2)” will be in “OPEN” condition, and

“Drain Valve (DV1)”, “Additional Port Fitted With Valve (AP1)”, Nitrogen Supply Valve (NSV ) and Nitrogen Drain Valve(NDV ) should be in “CLOSED” condition .

A still further aspect of the present invention is directed to said system wherein before conducting Pressure Testing of Accumulator, it is ensured that “Auto Shut-Off Valve ( ASV )” , “Isolation Valve Of Accumulator ( AIV1) ” , “Oil Drain Valve 1 (DV1)“ and “Oil Drain Valve 2 (DV2) “ of Accumulator , “Nitrogen Supply ( NSV )“ and “Nitrogen Drain Valve( NDV)”, “Additional Port Fitted With Valve (AP1) “ should be in “ CLOSED” condition, and

setting of Relief Valve of one of Hydraulic Pump is increased by 20 Kg/Cm2 or more, than the Testing Pressure of the said Accumulator and then delivery port of Pump to be connected to Additional Port Fiited With Valve(AP1) through suitable Hose ( of Higher Pressure Rating ).

Another aspect of the present invention is directed to said system wherein during pressure testing of accumulator, the “Safety Valve( SV )” needs to be isolated by operating the “Isolation Valve(NIV1)” incorporated between “Safety Valve” and Accumulator so that draining out the nitrogen and oil from the Accumulator before testing is not needed.

Yet another aspect of the present invention is directed to said system wherein after isolating Safety Valve(SV) , pressurized nitrogen to be supplied through Nitrogen Supply Valve(NSV) to Accumulator, until the Accumulator reaches its testing pressure and then Nitrogen Supply Valve (NSV) made “CLOSED” and after testing of Accumulator is done, the hydraulic system is restored to its normal working condition.

The above said procedure can be carried out only in case of availability of source of nitrogen with sufficient quantity and required pressure with respect to test pressure of Accumulator.

If the nitrogen with sufficient quantity and required pressure is not available, then testing of Pressure Vessel will be carried out with the help of Pump only.

A further aspect of the present invention is directed to a method to carry out hydraulic pressure test of the pressure vessels or accumulators involving the system as described above comprising the steps involving

said accumulator fitted with auto-shut off valve ( ASV ), isolation valve (AIV1) , accumulator oil drain valve ( DV1 ), nitrogen supply valve ( NSV) , safety valve ( SV) , nitrogen drain valve ( NDV ) connected to atmosphere and also said
A) isolation valve of nitrogen ( NIV1) fitted between safety valve and accumulator ;
B) oil drain valve ( DV2) ;
C) additional port fitted with valve ( AP1 ), for facilitating pressure testing of accumulator , the method including:
during normal working said “auto shut-off valve ( ASV)” , “isolation valve ( AIV1 )” of accumulator “isolation valve ( NIV1 ) “ before safety valve , “drain valve ( DV2) ” are maintained in open condition while said “drain valve (DV1 )” ,“additional port fitted with valve (AP1) “ , nitrogen supply ( NSV ) and nitrogen drain valve ( NDV ) in “ closed” condition ; and wherein
during pressure testing of accumulator , isolate the “safety valve( SV )” involving said “isolation valve ( NIV1) ” between safety valve and accumulator thereby
avoiding draining the nitrogen and oil from the accumulator and wherein before conducting pressure testing , ensuring that , “auto shut-off valve ( ASV )” , “isolation valve of accumulator ( AIV1) ” , “oil drain valve 1 (DV1)“ and “oil drain valve 2 (DV2) “of accumulator , “nitrogen supply ( NSV )“and “nitrogen drain valve( NDV)” , ,“additional port fitted with valve (AP1) “ are in “ closed” condition.

A still further aspect of the present invention is directed to said method comprising the steps of:
(i)isolating the “Safety Valve( SV )” by operating the “Isolation Valve(NIV1)” incorporated between “Safety Valve” and Accumulator without the need for draining out the nitrogen and oil from the Accumulator before testing;
(ii)keeping “Auto Shut-Off Valve ( ASV )” , “Isolation Valve Of Accumulator ( AIV1)”, “Oil Drain Valve 1 (DV1)“ and “Oil Drain Valve 2 (DV2)” of Accumulator , “Nitrogen Supply ( NSV )“ and “Nitrogen Drain Valve( NDV)”, “Additional Port Fitted With Valve (AP1) “in “ CLOSED” condition prior to testing, and
(iii) setting of Relief Valve of connecting Hydraulic Pump is increased by 20 Kg/Cm2 or more, than the Testing Pressure and then delivery port of said Pump to be connected to Additional Port Fiited With Valve(AP1) through suitable Hose ( of Higher Pressure Rating);
(iv) supplying pressurized nitrogen through Nitrogen Supply Valve(NSV) to Accumulator, until the Accumulator reaches its Testing Pressure and then Nitrogen Supply Valve (NSV) made “CLOSED” and maintained for desired duration as per standard test norms; and
(v) restoring the hydraulic system to its normal working condition after testing of Accumulator is done.

A still further aspect of the present invention is directed to said method wherein the testing time required is saved by 50% i.e., from 16 hours to 8 hours time depending upon the capacity of the vessel.

The above and other aspects and advantages of the present invention are described hereunder in greater details with reference to the following accompanying non limiting illustrative drawings.
BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS

Figure 1: shows the conventional hydraulic testing circuit of pressure vessels or accumulators requiring disconnection of the vessel from equipment of application during testing and longer downtime of equipment to which it is connected.

Figure 2: shows the hydraulic testing circuit for pressure vessels or accumulators according to present invention without the need for disconnecting the equipment of application from the pressure vessel and saving manpower, time and cost.

DETAILED DESCRIPTION OF THE INVENTION WITH REFERENCE TO THE ACCOMPANYING DRAWINGS

The present invention is directed to provide a system of testing circuit for hydraulic testing of pressure vessels/accumulators and a method of such pressure testing in a simple, safe and faster manner without the need for disconnecting the pressure vessel from the equipment of application thus saving lot of time and incidental costs and avoid down time of equipments.

To emphasize the benefits of system and method of the present invention, the applicants prefer to illustrate the limitations of the existing facilities for testing of hydro-pneumatic type pressure vessels in relation to accompanying Figure 1 as follows:

In applicants’ existing hydraulic system, referring to Fig-1, include the components connected to it as the following-
The Accumulator is fitted with Auto-Shut Off Valve ( ASV ), Isolation Valve (AIV1), accumulator oil Drain Valve ( DV1 ), Nitrogen Supply Valve ( NSV) , Safety Valve ( SV) , Nitrogen Drain Valve ( NDV ) connected to atmosphere.

The function of “Accumulator” here is to act as an energy reservoir for the system and also its level column indicators facilitates the hydraulic system to run in “auto” mode .

The function of “Auto-Shut Off Valve ( ASV)” is to protect the hydraulic system, during any power failure condition or during any oil leakage into the system.

The function of “Safety Valve(SV)” is to protect the accumulator and its connected accessories (viz : pipe lines, nitrogen supply/drain valve etc) during any sudden pressure surge into the system .

During normal working of hydraulics system, Auto Shut-Off Valve( ASV), Isolation Valve ( AIV1) should be in “OPEN” condition all the time and the Oil Drain Valve (DV1) of accumulator, Nitrogen Supply Valve (NSV) and Nitrogen Drain Valve (NDV) should be in “CLOSED” condition.

During normal working, pressurized oil from hydraulic Pumps feed both to System and Accumulator. After the oil level into accumulator reaches to high working level, hydraulic pumps start unloading the Relief Valve and as per the oil requirement of Actuators ( Hydraulic Cylinders etc.), pressurized oil provided by accumulator. As soon as the level of Accumulator goes to low working level , hydraulic Pumps again start loading the relief valve and again the pressurized oil from Pump goes to System and Accumulator upto its high working level, and then , again hydraulic Pumps start unloading the Relief Valve . This process runs in the above manner endlessly , unless any external factors/error creates any discrepancy in the system.

Referring to Fig-1 showing the existing system of hydraulic circuit with Accumulators, during conventional pressure testing of accumulator, the Safety Valve(SV) has to be isolated; for this requirement, the nitrogen and oil from the accumulator has to be drained out and hence the whole hydraulic system taken into shut-down condition, during pressure testing of accumulator. After isolating Safety Valve(SV) , oil is to be filled into Accumulator upto its HIGH working level of accumulator. It is to be noted here that during filling of oil in to accumulator, “Auto Shut-Off Valve(ASV)”, “Isolation Valve(AIV1)” would be in “OPEN” condition and the “Oil Drain Valve(DV1)” of Accumulator, “Nitrogen Supply Valve(NSV)“ and “Nitrogen Drain Valve(NDV)” should be in “CLOSED” condition.

When the level of oil into the accumulator reaches to HIGH working level , hydraulic Pumps to be made OFF. Also “Auto Shut-Off Valve (ASV)”, “Isolation Valve( AIV1)” will be put into “CLOSED“ condition. Pressurized nitrogen to be supplied through Nitrogen Supply Valve (NSV) to Accumulator, until the Accumulator reaches its testing pressure and then Nitrogen Supply Valve (NSV) made “CLOSED”. In this way the conventional pressure vessels’ testing is conducted. After testing of Accumulator is done, the hydraulic system is restored to its normal working condition.
Nitrogen is used in normal operation of accumulator and also during Pressure Testing because of following reasons:
The said Accumulator is a Hydro-Pneumatic type and is required to maintain the System Pressure. In the normal operation of System, Pressure is maintained with the help of Nitrogen as it is an inert gas , clean , free from moisture and dust.
During Pressure testing of Pressure Vessels, Pressurized Nitrogen to be supplied through Nitrogen Supply Valve (NSV) to Accumulator, until the Accumulator reaches its Testing Pressure.
In the modified hydraulic system of present invention as shown in accompanying Fig.-2 , the components present are as follows:
Accumulator is fitted with Auto-Shut Off Valve(ASV), Isolation Valve (AIV1), accumulator oil Drain Valve (DV1), Nitrogen Supply Valve (NSV), Safety Valve (SV), Nitrogen Drain Valve(NDV) connected to atmosphere.

All the above mentioned components were also the part of old existing hydraulic system . The list of newly added components to modified hydraulic system are as follows:
A) Isolation Valve Of Nitrogen (NIV1)(Class 2500) fitted between safety valve and Accumulator.
B) Oil Drain Valve (DV2) (Class 2500) .
C) Additional Port Fitted With Valve(AP1), (Class 2500) for facilitating pressure testing of Accumulator .

During normal working of modified hydraulic system according to present invention, “Auto Shut-Off Valve (ASV)”, “Isolation Valve(AIV1)” of Accumulator “Isolation Valve(NIV1)” before “Safety Valve”, “Drain Valve(DV2)” will be in “OPEN” condition.

“Drain Valve (DV1)”, “Additional Port Fitted With Valve (AP1)”, Nitrogen Supply Valve (NSV ) and Nitrogen Drain Valve(NDV ) should be in “CLOSED” condition .

Referring FIG-2, during pressure testing of accumulator , the “Safety Valve( SV )” needs to be isolated. For this “Isolation Valve(NIV1)” has already been incorporated between “Safety Valve” and Accumulator .

In this way, now in new modified system draining out the nitrogen and oil from the Accumulator before testing is not needed, as was done previously with existing system. Before Conducting Pressure Testing , make sure that , “Auto Shut-Off Valve ( ASV )” , “Isolation Valve Of Accumulator ( AIV1) ” , “Oil Drain Valve 1 (DV1)“ and “Oil Drain Valve 2 (DV2) “ of Accumulator , “Nitrogen Supply ( NSV )“AND “Nitrogen Drain Valve( NDV)” , “Additional Port Fitted With Valve (AP1) “ should be in “ CLOSED” condition .

Setting of Relief Valve of one of Hydraulic Pump should be increased by 20 Kg/Cm2 or more, than the Testing Pressure of the said Accumulator. Now the delivery port of Pump to be connected to Additional Port Fitted With Valve(AP1) through suitable Hose ( of Higher Pressure Rating ).

During normal working of hydraulic system, pressure of Relief Valve should be set at (20 Kg/Cm2 higher or more), than the safe working pressure of hydraulic system, required for the smooth running of the hydraulic system.

It can easily be understood, by the following illustration:
If the Safe Working Pressure (SWP) of the system is 100 Kg/Cm2 , then the setting of Relief Valve should be set at around 120 Kg/Cm2 to 125 Kg/Cm2 .

Now for testing of Accumulator, at its Test Pressure, pressure of the Relief Valve should be set at (20 Kg/Cm2 higher or more ), than the required Test Pressure (TP) of Accumulator .

For example, if the Test Pressure of the Accumulator is 165 Kg/Cm2, then the Relief Valve to be set at around 180 Kg/Cm2 to 185Kg/Cm2 .

As far as boundary condition of accumulator testing is concerned, the maximum pressure rating of Relief Valve should be sufficiently higher than the Test Pressure.

The PRECAUTIONS to be taken for safe pressure testing of accumulator are as follows:
• CONDITION OF HOSES AND ADAPTORS USED FOR PRESSURE TESTING , SHOULD BE IN GOOD CONDITION AND PROPERLY TIGHTENED .
• SAFE WORKING PRESSURE RATING FOF HOSES USED FOR PRESSURE TESTING SHOULD BE SUFFICIENTLY HIGHER THAN THE TEST PRESSURE .
• ENSURE THE CRIMPING PORTION OF THE HOSES AND ADAPTORS , SHOULD BE IN GOOD CONDITION AND SHOULD BE FREE FROM ANY OIL LEAKAGE , DURING PRESSURE TESTING.
• CHECK THE CONDITION OF PIPE LINES, VALVES USED FOR PRESSURE TESTING TO BE CHECKED FOR ANY DEFECT/EXTERNAL DAMAGE , BEFORE CONDUCTING PRESSURE TESTING.
• ENSURE THAT THE PRESSURE RATING OF RELIEF VALVE SHOULD BE, SET AT (20 Kg/Cm2 HIGHER OR MORE ) , THAN THE REQUIRED TEST PRESSURE ( TP ) OF ACCUMULATOR , BEFORE CONDUCTING PRESSURE TESTING .
• STRICTLY ENSURE THAT , BEFORE PRESSURE TESING , WHICH VALVE IS TO BE IN “ OPEN” CONDITION AND WHICH VALVES TO BE IN “ CLOSED “ CONDITION .
• BEFORE CONDUCTING PRESSURE TESTING, MAKE SURE THAT THE PROCEDURE OF PRESSURE TESTING SHOULD BE CLEARLY MENTIONED, STATED AND WELL UNDERSTOOD AMONG THE PERSONS, INVOLVED IN PRESSURE TESTING .

The salient advantageous features of the present invention are as follows:
1. Safety valve of the pressure vessel is connected through an isolation valve.
2. An additional drain valve and one port added to the circuit for connecting high pressure pump for testing purpose.
3. Testing of pressure vessels can be done with less down time of equipments.
4. Design can be incorporated even in the existing pressure vessels.
5. Helps in design of new pressure vessels with this testing circuit.

, Claims:We Claim:

1. A system of testing circuit for hydraulic testing of pressure vessels of accumulators comprising:
Auto shut off valve (ASV), isolation Valve (AIV1), accumulator oil Drain Valve (DV1),Nitrogen Drain Valve (NDV) connected to atmosphere and wherein the system includes :
an Isolation Valve of Nitrogen (NIV1) fitted between safety valve and accumulator;
an Oil Drain Valve (DV2);and
an additional port fitted with Valve (AP1) for facilitating testing of accumulator free of need for disconnecting said pressure vessel from equipment of application and depressurizing the vessel and removing safety valve and plugging it and again pressurizing it to test pressure before testing and avoiding related downtime and manpower.

2. The system as claimed in claim 1 comprising
a hydraulic circuit including said Pressure Vessels or Accumulator for storing and supplying pressurized oil to equipments of application including hydraulic actuators in Plate Mill wherein each said Accumulator is fitted with Auto-Shut Off Valve(ASV), Isolation Valve (AIV1), accumulator oil Drain Valve (DV1), Nitrogen Supply Valve (NSV), Safety Valve (SV), Nitrogen Drain Valve(NDV) connected to atmosphere, an isolation Valve Of Nitrogen (NIV1)(Class 2500) fitted between safety valve and Accumulator, an Oil Drain Valve (DV2) (Class 2500), and
an Additional Port Fitted With Valve(AP1), (Class 2500) for facilitating pressure testing of Accumulator without disconnecting from application equipment, and wherein
hydraulic pump with Relief Valve is provided to feed hydraulic oil at desired pressure to the system and accumulator; wherein in normal operation after the oil level into accumulator reaches to high working level, hydraulic pumps start unloading the Relief Valve and as per the oil requirement of Actuators ( Hydraulic Cylinders etc.), pressurized oil provided by accumulator; and as soon as the level of Accumulator goes to low working level , hydraulic Pumps again start loading the relief valve and again the pressurized oil from Pump goes to System and Accumulator upto its high working level, and this cycle repeats endlessly;

said “Accumulator” act as an energy reservoir for the system and also its level column indicators facilitates the hydraulic system to run in “auto” mode;

said “Auto-Shut Off Valve ( ASV)” is provided to protect the hydraulic system, during any power failure condition or during any oil leakage into the system; and

said “Safety Valve(SV)” is provided to protect the accumulator and its connected accessories (viz : pipe lines, nitrogen supply/drain valve etc) during any sudden pressure surge into the system.

3. The system as claimed in anyone of claims 1 or 2 wherein said pressure vessels (hydro-pneumatic type ) are with capacities varying from 2000 litres to 9000 litres and with working pressure ranging from 6 kg/cm2 to 170 kg/cm2 , which need to be tested hydraulically once in every two years (as per The Factories Act 1948).

4. The system as claimed in anyone of claims 1 to 3 wherein during normal working of said hydraulic system, “Auto Shut-Off Valve (ASV)”, “Isolation Valve(AIV1)” of Accumulator, “Isolation Valve(NIV1)” before “Safety Valve”, “Drain Valve(DV2)” will be in “OPEN” condition, and

“Drain Valve (DV1)”, “Additional Port Fitted With Valve (AP1)”, Nitrogen Supply Valve (NSV ) and Nitrogen Drain Valve(NDV ) should be in “CLOSED” condition .

5. The system as claimed in anyone of claims 1 to 4 wherein before conducting Pressure Testing of Accumulator, it is ensured that “Auto Shut-Off Valve ( ASV )” , “Isolation Valve Of Accumulator ( AIV1) ” , “Oil Drain Valve 1 (DV1)“ and “Oil Drain Valve 2 (DV2) “ of Accumulator , “Nitrogen Supply ( NSV )“ and “Nitrogen Drain Valve( NDV)”, “Additional Port Fitted With Valve (AP1) “ should be in “ CLOSED” condition, and

setting of Relief Valve of one of Hydraulic Pump is increased upto 20 Kg/Cm2 or more, higher than the Testing Pressure and then delivery port of Pump to be connected to Additional Port Fiited With Valve(AP1) through suitable Hose ( of Higher Pressure Rating ).

6. The system as claimed in anyone of claims 1 to 5 wherein during pressure testing of accumulator, the “Safety Valve( SV )” needs to be isolated by operating the “Isolation Valve(NIV1)” incorporated between “Safety Valve” and Accumulator so that draining out the nitrogen and oil from the Accumulator before testing is not needed.

7. The system as claimed in anyone of claims 1 to 6 wherein after isolating Safety Valve(SV) , pressurized nitrogen to be supplied through Nitrogen Supply Valve(NSV) to Accumulator, until the Accumulator reaches its testing pressure and then Nitrogen Supply Valve (NSV) made “CLOSED” and after testing of Accumulator is done, the hydraulic system is restored to its normal working condition.

8. A method to carry out hydraulic pressure test of the pressure vessels or accumulators involving the system as claimed in claims 1 to 7 comprising the steps involving

said accumulator fitted with auto-shut off valve ( ASV ), isolation valve (AIV1) , accumulator oil drain valve ( DV1 ), nitrogen supply valve ( NSV) , safety valve ( SV) , nitrogen drain valve ( NDV ) connected to atmosphere and also said
A) isolation valve of nitrogen ( NIV1) fitted between safety valve and accumulator ;
B) oil drain valve ( DV2) ;
C) additional port fitted with valve ( AP1 ), for facilitating pressure testing of accumulator , the method including:
during normal working said “auto shut-off valve ( ASV)” , “isolation valve ( AIV1 )” of accumulator “isolation valve ( NIV1 ) “ before safety valve , “drain valve ( DV2) ” are maintained in open condition while said “drain valve (DV1 )” ,“additional port fitted with valve (AP1) “ , nitrogen supply ( NSV ) and nitrogen drain valve ( NDV ) in “ closed” condition ; and wherein
during pressure testing of accumulator , isolate the “safety valve( SV )” involving said “isolation valve ( NIV1) ” between safety valve and accumulator thereby
avoiding draining the nitrogen and oil from the accumulator and wherein before conducting pressure testing , ensuring that , “auto shut-off valve ( ASV )” , “isolation valve of accumulator ( AIV1) ” , “oil drain valve 1 (DV1)“ and “oil drain valve 2 (DV2) “of accumulator , “nitrogen supply ( NSV )“and “nitrogen drain valve( NDV)” , “additional port fitted with valve (AP1) “ are in “ closed” condition.

9. The method as claimed in claim 8 comprising the steps of:
(i)isolating the “Safety Valve( SV )” by operating the “Isolation Valve(NIV1)” incorporated between “Safety Valve” and Accumulator without the need for draining out the nitrogen and oil from the Accumulator before testing;
(ii)keeping “Auto Shut-Off Valve ( ASV )” , “Isolation Valve Of Accumulator ( AIV1)”, “Oil Drain Valve 1 (DV1)“ and “Oil Drain Valve 2 (DV2)” of Accumulator , “Nitrogen Supply ( NSV )“ and “Nitrogen Drain Valve( NDV)”, “Additional Port Fitted With Valve (AP1) “in “ CLOSED” condition prior to testing, and
(iii)setting of Relief Valve of connecting Hydraulic Pump is increased upto 20 Kg/Cm2 or more, higher than the Testing Pressure and then delivery port of said Pump to be connected to Additional Port Fiited With Valve(AP1) through suitable Hose ( of Higher Pressure Rating);
(iii)supplying pressurized nitrogen through Nitrogen Supply Valve(NSV) to Accumulator, until the Accumulator reaches its Testing Pressure and then Nitrogen Supply Valve (NSV) made “CLOSED” and maintained for desired duration as per test norms; and
(iv)restoring the hydraulic system to its normal working condition after testing of Accumulator is done.

10. The method as claimed in anyone of claims 8 or 9 wherein the testing time required is saved by 50% i.e., from 16 hours to 8 hours time depending upon the capacity of the vessel.

Dated this the 30th day of November, 2022
Anjan Sen
Of Anjan Sen & Associates
(Applicant’s Agent)
IN/PA-199