DESC:FORM 2
THE PATENTS ACT, 1970
(39 of 1970)
&
The Patent Rules, 2003
COMPLETE SPECIFICATION
(See sections 10 & rule 13)
1. TITLE OF THE INVENTION
AN INTEGRATED HYDRAULIC SYSTEM FOR PROOF PRESSURE TESTING OF CYLINDERS AND SWIVEL JOINTS OF HYDRAULIC EXCAVATORS
2. APPLICANT (S)
NAME NATIONALITY ADDRESS
BEML LIMITED IN BEML Soudha, No 23/1, 4th Main S.R. Nagar, Bengaluru- 560027, Karnataka, India.
3. PREAMBLE TO THE DESCRIPTION
COMPLETE SPECIFICATION

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

FIELD OF INVENTION:
[001] The present invention relates to the field of testing system. The present invention in particular relates to an integrated hydraulic system for proof pressure testing of cylinders and swivel joints of hydraulic excavators.
DESCRIPTION OF THE RELATED ART:
[002] The hydraulic test device and high-pressure hydraulic testing machine are widely used in the production, development and research of various hoses such as quality inspection units, various vehicle parts manufacturing units, product quality monitoring stations, and scientific research institutions. The pressure test system consists of a pressurization system, a control and display system.
[003] The pressurization system mainly completes the pressurization and pressure maintenance of the system, which can ensure long-term pressurization and pressure maintenance.
[004] Reference may be made to the following:
[005] Publication No. RU2783583 relates to the field of test equipment in mechanical engineering and can be used for dynamic testing of high-pressure hoses. Stand constitutes a metal structure containing a frame with a tank installed thereon. A pumping unit is secured on the upper flange of the tank. The pumping unit is connected to the hydraulic panel installed on the frame by a pipeline. Installed on the hydraulic panel are: a check valve, where to a pressure valve and an inlet distributor with an electromagnet are connected by a channel. A pressure gauge is also connected to the hydraulic panel via a gate. A hydraulic accumulator is connected to the channel of the hydraulic panel used to connect the pressure valve with the inlet distributor, thereby being located between the pumping unit and the inlet distributor. An adjustable throttle is secured on the upper wall of the frame and located between the inlet distributor and the tested hose. A pressure sensor and an outlet distributor with an electromagnet are installed at the outlet of the tested hose. The pressure sensor is electrically connected with the signal converter, the programmable logic controller, and the display, located in the control cabinet secured on the frame. The electromagnets and of the distributors and are also electrically connected with the programmable logic controller. Effect: expanded range of testing pressure change rate adjustment, guaranteed distribution of pressure along the entire length of the tested hose, and higher reliability of testing.
[006] Publication No. EP2526395 relates to a hydrostatic pressure testing system for hydrostatic pressure testing of pipe or other vessels. A control center may include a computer program that monitors, records, and controls the system during testing. A test fluid assembly may include a fill conduit capable of providing a test fluid to an inlet section of a vessel to be tested in response to a command from the computer program. A pressure-release safety assembly may have a vent conduit in fluid communication between an outlet section of the vessel and a safety valve. The safety valve may be in fluid communication with a bleed tank for storing an outlet flow of test fluid from the vessel. The safety valve is actuated to relieve fluid pressure in the vessel in response to a selective condition. A method of using the system to conduct hydrostatic pressure testing is also described.
[007] Publication No. CN1075579 relates to the system comprises a first flow valve which controls the fluid flow to the motor, and a swivel able control stick which changes the position of the flow valve, using a control fluid. Behind the flow valve is fitted pressure equalising valve for the motor fluid pressure. A hydraulic ram carries out an extension on retraction movement under the effect of the working fluid. The ram action actuates the jib lifting or lowering motion. A second flow valve controls the working fluid flow to the hydraulic ram, and a second pressure equalising valve is fitted behind it. A load sensor valve is coupled to the two pressure equalising valves via a load sensor line, and responds to the load sensor pressure in the line. It controls the flow vol. of the working fluid. A torque control completes the system.
[008] Publication No. CN203869821 relates to a hydraulic pressure test apparatus for an explosion-proof box. The hydraulic pressure test apparatus consists of standing columns, upper compaction oil cylinders, an upper compaction end cover, a pushing trolley, a rising rack, an overall pedestal, a bearing pedestal, a right bracket, a right compaction oil cylinder, a right compaction end cover, a left bracket, a left compaction oil cylinder, a left compaction end cover and a stamping device. The standing columns are arranged at the overall pedestal, wherein he standing columns and the overall pedestal are in a welding assembling mode. Two circular holes are formed in the upper portions of the standing columns; and the upper compaction oil cylinders are arranged in the circular holes of the standing columns. The upper compaction end cover and the upper compaction oil cylinders are connected by bolts. The bearing pedestal is arranged on the overall pedestal. Sixteen groups of springs are arranged at the bottom of the pushing trolley. The bearing pedestal is arranged among the wheels of the pushing trolley; and the rising rack is arranged on the pushing trolley. The right bracket is arranged on the overall pedestal and the right bracket and the overall pedestal are connected by bolts. A circular hole is formed in the right bracket; the right compaction oil cylinder is arranged in the circular hole of the right bracket; and the right compaction end cover and the right compaction oil cylinder are connected by bolts. The left bracket is arranged on the overall pedestal, wherein the left bracket and the overall pedestal are connected by bolts; a circular hole is formed in the left bracket and the left compaction oil cylinder is arranged in the circular hole of the right bracket; and the left compaction end cover and the left compaction oil cylinder are connected by bolts. The stamping device is connected with an explosion-proof box for testing. According to the technical scheme, the structure of the test apparatus is reasonable and compact; the apparatus can be controlled conveniently and is secure and reliable; time and effort are saved; the universality is good; and the test objectives can be achieved conveniently with high efficiency.
[009] Publication No. CN203414263 relates to equipment for testing the hydraulic pressure of a component of an explosion-proof motor, and the equipment comprises an extruding device and a pedestal. The extruding device consists of a left hydraulic machine and a right hydraulic machine. The left hydraulic cylinder of the left hydraulic machine is fixedly connected to a left support, and the right hydraulic cylinder of the right hydraulic machine is fixedly connected to a right support. A water tank is disposed between the left support and the right support. The water tank is located under the left push rod of the left hydraulic machine and the right push rod of the right hydraulic machine. The right end of the left push rod is disposed to be opposite to the left end of the right push rod. The left support and the right support are respectively fixed on the pedestal. After the hydraulic pressure of a to-be-tested piece, which is extruded between the left push rod and the right push rod, is tested, water for a test flows into the water tank directly after the to-be-tested piece is taken down because the water tank is disposed under the left and right push rods of the equipment. Moreover, the water which flows into the water tank can be used for the next test. Accordingly, the water for the test can be reused, thereby saving the source.
[010] Publication No. CN102564860 relates to a rotating joint durability testing principle and a full-automatic testing machine are applied in the technical field of engineering mechanical test. The full-automatic testing machine comprises a hydraulic loading system, a servo motor driving system and a programmable Logic Controller (PLC) system. During the operation of a rotating joint, the hydraulic loading system input hydraulic oil with rated pressure in an oil channel of the rotating joint, then the servo motor driving system enables the rotating shaft and the casing of the rotating joint to rotate relatively, and adjusts the rotating speed, the rotating direction and the rotating angle of the relative rotation, and finally the PLC measuring and controlling system controls the gain and loss of electricity of electromagnetic valves and the operation of the servo motor, automatically measures the oil temperature, the oil flow quantity, the oil pressure, the driving torque and the rotating speed of the rotating joint, processes signals and displays collected data in real time. The rotating joint durability testing principle and the full-automatic testing machine can simulate the actual working condition of the rotating joint, and research the tightness of the rotating joint sealing member, effects of temperature towards the driving torque and the strength of rotating joint parts under the pressure in the process of 2000-hour running.
[011] Publication No. CN108106834 relates to a hydraulic excavator rotation performance test device and a test method and belongs to the construction machinery technical field. The test device includes an optical fiber optic gyro module, pressure sensors, a data acquisition instrument and a data analysis module; the fiber optic gyroscope module is fixed on a rotary excavator; the pressure sensors are installed on the pilot oil passages of a handle; the fiber optic gyro module and the pressure sensors are connected with the data acquisition instrument through a signal line; and measured data are processed by the data analysis module, so that a corresponding test curve can be obtained. With the hydraulic excavator rotation performance test device and the test method of the invention adopted, a rotation braking angle curve, a rotation angular velocity curve, the angular acceleration curves of an acceleration/deceleration section, braking deceleration time and start-up acceleration time can be accurately measured; the problem of inconvenience in installation caused by using a conventional encoder to perform rotation measurement and the problem of low accuracy of angular velocity and angular acceleration which are obtained on the basis of angular displacement can be solved. The hydraulic excavator rotation performance test device and the test method of the present invention have the advantages of simple and convenient installation and high measurement accuracy.
[012] Publication No. CN207472518 relates to a hydraulic component capability test technical field especially is an excavator hydraulic component capability test device, including a sealed container and no. Two sealed container, the outer fixed surface of a sealed container's lower extreme installs pressure sensor no. One, and a sealed container's inside movable mounting has a sealed piston, fixed surface installs the depression bar outside the upper end of sealed piston, a sealed container's inside lower extreme fixed mounting has the baroceptor. An excavator hydraulic component capability test device, be equipped with no. Two sealed container, no. Two pressure sensor and no. Two sucking discs, increase sealed container's number, can intuitive judgment go out hydraulic component's gas tightness, conveniently do further detection to hydraulic component's gas tightness, can select different radial sucking discs according to the detection needs of test point moreover, increased test instrument's application range, bring better use prospect.
[013] Publication No. CN107677433 relates to the hydraulic element performance testing technical field, and especially relates to an excavator hydraulic element performance testing device comprising a no.1 seal container and a no.2 seal container; the bottom outer surface of the no.1 seal container is fixedly provided with a no.1 pressure sensor; a seal piston is movably arranged in the no.1 seal container; the top outer surface of the seal piston is fixedly provided with a pressure bar; an air pressure sensor is fixedly arranged on the internal bottom of the no.1 seal container. The excavator hydraulic element performance testing device is provided with the no.2 seal container, a no.2 pressure sensor, and a no.2 sucker; the seal container number is increased, thus directly determining the hydraulic element airtight, and further easily detecting the hydraulic element airtight; the sucker of different radiuses can be selected according to detection needs of the test points, thus increasing the testing device usage scope, and providing a better usage prospect.
[014] Publication No. CN102183426 relates to a novel method for testing the durability of a track tensioning device of a hydraulic excavator. The method comprises the following steps of: calculating a maximum working pressure of an oil cylinder during working according to a maximum load of the track tensioning device of the hydraulic excavator and the diameter of the oil cylinder, taking the maximum working pressure as a maximum hydraulic value provided by a hydraulic pump unit, and connecting the track tensioning device and the hydraulic pump unit with an operating system through an oil supply pipeline; removing grease inside the oil cylinder of the track tensioning device, and realizing periodic compression of a tensioning spring by using periodic reciprocating motions of a piston and the oil cylinder of the track tensioning device; recording a spring compressed frequency before the track tensioning device fails so as to determine the durability of the track tensioning device; and detecting and analyzing a failure mode so as to provide basis for improvement on the durability of the track tensioning device. By using the oil cylinder of the track tensioning device, the reciprocating motion of the tensioning spring is realized, and an auxiliary hydraulic cylinder is avoided; therefore, the whole test equipment is simplified, and the safety protection level is high.
[015] Publication No. CN205750426 relates to a hydraulic shovel test system, sensor module includes pressure transmitter, turbine flowmeter, displacement sensor, the gyration encoder, signal conditioning module includes the isolated gate, the RS422TTL converter, the compact RIO platform includes the IO module, NI9118 FPGA machine case, NI9025 real -time controller, hydraulic shovel and sensor module are connected, the signal of pressure transmitter output directly is connected with 9205 modules of NI through the shielded wire, turbine flowmeter, the signal of displacement sensor output inserts 9205 modules of NI respectively after the isolated gate conversion, the NI9215 module, the gyration encoder passes through the RS422TTL converter and is connected with the NI9401 module, the IO module is connected with 9118 FPGA of NI machine case, NI9118 FPGA machine case passes through the PCI bus and is connected with NI 9025 real -time controller, NI9025 real -time controller and upper computer connection, moreover, the steam generator is simple in structure, can carry out synchronous sampling to excavator system parameter data, realize the high accuracy control of excavator, the system development degree of difficulty is little, short periodic time, low cost, can move stably under complex operating condition.
[016] Publication No. CN108571476 relates to the technical field of hydraulic hose testing, in particular to a testing device of a hydraulic hose high-temperature pressure resistant test. The device comprises an oil groove, a variable pump, an overflow valve, a first one-way valve, a second one-way valve, an accumulator, a three-position four-way electromagnetic reversing valve, a pressurizing cylinder, a heating device, a quantitative pump and a manual intercepting valve. By means of the device, high-temperature and high-pressure oil liquid can be provided for a hydraulic hose, so that measuring is more convenient and rapid when the high-temperature pressure resistant test of the hydraulic hose is conducted to improve the working efficiency.
[017] In the conventional technology, separate intensifier is used for proof pressure testing of hydraulic components. Hence there needed a system which does not uses separate intensifier.
[018] In order to overcome above listed prior art, the present invention aims to provide an integrated hydraulic system for proof pressure testing of cylinders and swivel joints of hydraulic excavators.
OBJECTS OF THE INVENTION
[019] The principal object of the present invention is to provide an integrated hydraulic system for proof pressure testing of cylinders and swivel joints of hydraulic excavators.
[020] Another object of the present invention is to provide a cost effective and simplified hydraulic system which does not uses separate intensifier.
SUMMARY OF THE INVENTION:
[021] The present invention relates to an integrated hydraulic system for proof pressure testing of cylinders and swivel joints of hydraulic excavators. As shown in hydraulic circuit at figure 1, the system comprises hydraulic tank (1), shut off valve (2), hydraulic pump (4), electric motor (5), directional control valve (7), relief valve (6), hydraulic cylinder (9), swivel joint (10) and pressure gauge/ pressure transducer (8). The pressure of rod side of hydraulic cylinder is intensified and same is utilized for proof pressure testing of the same cylinder & swivel joint simultaneously.
BREIF DESCRIPTION OF THE INVENTION
[022] It is to be noted, however, that the appended drawings illustrate only typical embodiments of this invention and are therefore not to be considered for limiting of its scope, for the invention may admit to other equally effective embodiments.
[023] Figure 1 shows Hydraulic circuit at integrated hydraulic system for proof pressure testing of cylinders and swivel joints of hydraulic excavators according to the present invention.
DETAILED DESCRIPTION OF THE INVENTION:
[024] The present invention relates to an integrated hydraulic system design for proof pressure testing of cylinders and swivel joints of hydraulic excavators which are connected in series (Pump flow –> Cylinder –> Swivel joint), using principle of pascal's law pressure intensification.
[025] As shown in below hydraulic circuit at figure- 1, the system consists of hydraulic tank (1), shut off valve (2), filter/ strainer (3), hydraulic pump (4), electric motor (5), relief valve (6), directional control valve (7), pressure gauge/ pressure transducer (8), hydraulic cylinder (9) and swivel joint (10).
[026] The system includes a hydraulic power pack which can operate up to 350 bar, a pressure sensor with digital display, shut off valves and a test fixture.
[027] The hydraulic power pack supplies high-pressure hydraulic fluid to the cylinder (9). The cylinder is secured in a fixture in-order to provide stable mounting location and prevent any movements or vibrations. Initially the cylinder will be operated for 10 - 20 reciprocating cycles. Then oil supply to cylinder is stopped in retracted position of piston in order to ensure Rod end side is filled with oil completely.
[028] Pre-fill the swivel joint (i.e., it can be pre-filled manually or by power pack or some quantity of oil can be transferred from existing cylinder during extension of cylinder).
[029] After fill of swivel joint, the system is ready for testing of cylinder and swivel joint simultaneously. At this point of time, the full quantity oil is available at rod end side and swivel joint.
[030] Oil will be supplied at head end port. Since the piston cannot move as the rod end port is connected to swivel joint port, the pressure of oil intensifies at rod end port (RE). The same amplified pressure is applied to the Inlet port-A (Port A is having one inlet and one outlet as shown Figure-1) of swivel joint (10) through high pressure hose while keeping Outlet port -A of swivel joint closed with dummy flange to simulate real-time operating conditions i.e., While continuation apply of hydraulic flow (pressure) at head end, the pressure at rod end side of hydraulic cylinder is intensified which is utilized for proof pressure testing of the cylinder & swivel joint simultaneously instead of testing one after other hence proof pressure test time is reduced and to improve productivity.
[031] The pressure sensor (8) is connected at rod end port of cylinder and same is connected to digital display. The pressure sensor and relief valve helps in maintaining the oil pressure within safe operating limits.
[032] Pressure Intensification phenomenon:
[033] Force (F) developed by a hydraulic cylinder = Hydraulic Pressure (P) x Area (A)
P = F/A
[034] The pressure intensification factor for each cylinder is fixed and is calculated using mathematical equations that take the area of the piston and cylinder bore into account as given below:
1. F = P*A
2. P1* A1|Head end = P2* A2|Rod end ;
A1 (Bore area) = ?/4 * d12 ;
A2 (Rod area) = ?/4* d22
A3 (Annulus area) = ( A1- A2)

3. Pressure intensified at Rod end side P2 = P1*(A1/ A3); The P1 pressure can be controlled via potentiometer in the hydraulic power pack system. When pressure P1 is varied, then P2 is varied by A1/A3 factor which is called as intensification factor.
4. Intensification factor ultimately refers to A1/A3.
5. Any cylinder can be chosen of different bore and annulus area as per requirement.
6. The amplified/intensified pressure is measured by a pressure sensor.
[035] Typically the proof pressure will be 1.25 to 2 times of operating pressure of the cylinder and swivel joint of excavators.
[036] In an embodiment, many test components can be connected to Rod side of hydraulic cylinder so that multiple test components can be pressurized simultaneously to the proof pressure value.
[037] Thus in the present invention, pump will not get overloaded since it is not directly connected to proof pressure test component. The required proof pressure is generated in rod side of hydraulic cylinder due to pressure intensification phenomenon. The hydraulic cylinder is used for pressure intensification. Hence, proof pressure will not act on oil supply pump.
[038] In the present invention the separate intensifier is not required. This is a cost effective and simplified hydraulic system.
[039] Numerous modifications and adaptations of the system of the present invention will be apparent to those skilled in the art, and thus it is intended by the appended claims to cover all such modifications and adaptations which fall within the true spirit and scope of this invention.
,CLAIMS:WE CLAIM:
1. An integrated hydraulic system for proof pressure testing of cylinders and swivel joints of hydraulic excavators comprises hydraulic tank (1), shut off valve (2), hydraulic pump (3), electric motor (4), relief valve (5), directional control valve (7), hydraulic cylinder (9), swivel joint (10) and pressure gauge/ pressure transducer (8) wherein the pressure of rod side of hydraulic cylinder is intensified and same is utilized for proof pressure testing of the same cylinder & swivel joint simultaneously.
2. The integrated hydraulic system for proof pressure testing of cylinders and swivel joints of hydraulic excavators, as claimed in claim 1, wherein at a time, cylinder and swivel joint can be tested simultaneously reducing proof pressure test time and improving productivity.
3. The integrated hydraulic system for proof pressure testing of cylinders and swivel joints of hydraulic excavators, as claimed in claim 1, wherein pump need not be rated for proof pressure testing since oil is supplied to head/piston end of cylinder and pressure intensification occurs in rod side of hydraulic cylinder hence the life of high-pressure pump which is supplying oil into the hydraulic circuit is enhanced.
4. The integrated hydraulic system for proof pressure testing of cylinders and swivel joints of hydraulic excavators, as claimed in claim 1, wherein if piston side of a double acting cylinder is pressurized and at the same time oil is prevented from escaping from the rod end side, pressure will increase in the rod end side due to smaller area in rod end side compare to piston end side.
5. The integrated hydraulic system for proof pressure testing of cylinders and swivel joints of hydraulic excavators, as claimed in claim 1, wherein N- number of test components are connected to rod side of hydraulic cylinder so that test components can be pressurized simultaneously to the proof pressure value.