Dynamic Logic Element For Controlling Pressure Limit In Hydraulic System

Abstract

The present invention relates to a stand-alone or inbuilt logical element associated with a hydraulic system for effective regeneration to improve the efficiency of any hydraulic system of a machine or equipment, including but not limited to farm machinery, industrial machinery, construction and mining machinery which uses hydraulic system. The logical element senses the cavitation or low pressure in the hydraulic system and automatically regulates and diverts the portion of hydraulic oil flow to caveated and required areas by regenerating through the anti-cavitation feature of the valve by automatically sensing and applying selective restriction to the set or adjustable pressure limit for the passage of oil.

Claims

1. An apparatus for regulating flow of fluid, comprising: a dynamic logical element having a pilot operated valve where a pilot line is connected to a pump line of a pump, said pilot operated valve senses a level of pressure restriction needed in tank line of a direction control valve to activate said dynamic logical element inversely proportionally to set pressure limit for the passage of said fluid to an optimum level in order to regulate the pressure and flow of said fluid in said tank line based on demand or flow of said fluid; and at least one sensor and controller that detects variable return line flow characteristics such as maximum return line flow rate and minimum return line flow rate of a cylinder and a motor, wherein said dynamic logical element controls the level of pressure restriction of fluid based on the variable return line flow characteristics of the cylinder which is connected to a first valve section and the motor which is connected to a second valve section of the direction control valve in order to maintain constant maximum allowable pressure limit, said dynamic logical element senses the cavitation being occurred in said direction control valve and redirects required fluid to desired section of said direction control valve to reduce said cavitation in said direction control valve, and the dynamic logical element (12) has adjustable or non-adjustable means applies restriction to the fluid flow to set the required pressure in the return line to optimize the effectiveness of regeneration of hydraulic system through anti cavitation function to the required area.

2. The apparatus as claimed in claim 1 comprising: a check valve which is mounted between tank line and service port of a second valve section, wherein said check valve allows maximum flow when there is a pressure restriction applied by said dynamic logical element.

3. The apparatus as claimed in claim 1, wherein said dynamic logical element senses cavitation occurring in said cylinder to redirect the flow of the fluid to the cavitation side of said cylinder via anti-cavitation valves to increase efficiency.

4. The apparatus as claimed in claim 1, wherein said dynamic logical element senses cavitation occurring in said motor to redirect the flow of said fluid to said cavitation via anti-cavitation valves to increase efficiency.

5. The apparatus as claimed in claim 1, wherein said tank line of said direction control valve is connected back to a tank through a cooler and a return line filter.

6. The apparatus as claimed in claim 1, wherein at least one pressure sensor is mounted on a specific service port which provides an input signal to the controller when there is a flow in the port and the controller sends an appropriate signal to the dynamic logical element to apply selective restriction.

7. The apparatus as claimed in claim 1, wherein said fluid is oil.

8. A system for regulating flow of fluid for reducing cavitation comprising: a direction control valve; a dynamic logical element as claimed in claim 1; a pump connected to said direction control valve which has a main relief valve and a High Pressure Carry Over (HPCO) line of the valve is connected back to a tank via an oil cooler and a return line filter, wherein a tank line of the valve is connected to said dynamic logical element which senses a pressure from a point between the pump and the main relief valve, wherein said dynamic logical element having a pilot operated valve where a pilot line is connected to a pump line of the pump; a hydraulic cylinder; and a hydraulic motor.

9. The system for regulating flow of fluid for reducing cavitation as claimed in claim 8 comprising: a check valve which is mounted between tank line and service port of a second valve section, wherein said check valve allows maximum flow when there is a pressure restriction applied by said dynamic logical element.

10. The system as claimed in claim 8, wherein said dynamic logical element senses cavitation occurring in said cylinder to redirect the flow of the fluid to the cavitation side of said cylinder via anti-cavitation valves to increase efficiency.

11. The system as claimed in claim 8, wherein said dynamic logical element senses cavitation occurring in said motor to redirect the flow of said fluid to said cavitation via anti-cavitation valves to increase efficiency.

12. The system as claimed in claim 8, wherein said tank line of said direction control valve is connected back to a tank through a cooler and a return line filter.

13. The system as claimed in claim 8, wherein at least one pressure sensor is mounted on a specific service port which provides an input signal to the controller when there is a flow in the port and the controller sends an appropriate signal to the dynamic logical element to apply selective restriction.

14. The system as claimed in claim 8, wherein said fluid is oil.

Description

BRIEF DESCRIPTION OF DRAWINGS

[0034] FIG. 1 illustrates a hydraulic circuit of the system according to an embodiment herein.

DETAILED DESCRIPTION OF THE INVENTION

[0035] FIG. 1 shows a circuit representing the working principle of the invention. A pump (3) is coupled to the power source (20) by suitable means and takes fluid (i.e. oil) from the tank (1) by a hose connection through a suction strainer (2).

[0036] The pump (3) outlet is connected to the valve (4) which has a main relief valve (5) and the HPCO (17) line of the valve is connected back to the tank (1) via oil cooler (18) and a return line filter (19). The tank line of the valve (4) is connected to the dynamically logical element (12) and the logic element (12) senses the system pressure from a point between pump (3) and valve (5).

[0037] The logic element can be an adjustable (12a) or non-adjustable orifice type (12b) or a check valve with adjustable (12c) or non-adjustable crack pressure type (12d).

[0038] The magnitude of restriction can be varied dynamically to enhance the usage of the system by using sensors and controller (16).

[0039] The output of logic element (12) is connected to tank (1) via cooler (18) and return line filter (19). The valve (4) has two valve sections (6, 7) in a parallel circuit. The two valve sections are (i) a first valve section (6) and (ii) a second valve section (7). Each valve section (6, 7) having a set of anti-cavitation cum shock relief valve (8, 9, 10, 11) fitted in the service port.

[0040] The logical element (12) is a pilot operated valve where the pilot line is connected to the P line which senses the pressure which inversely proportionally activates the logical element (12) to set value (e.g. pressure limit, fluid flow rate, etc.) which is connected to the tank line and thus regulates the pressure and flow in the tank line. The optimum level or the optimum value for pressure and fluid flow rate may vary with nature and type of fluid.

[0041] The first valve section (6) is connected to a hydraulic cylinder (13). The cylinder (13) is connected to a machine element in such a way that the gravitational pull arising out of the self-weight of the machine element is pulling the cylinder rod in the indicated direction.

[0042] The second valve section (7) is connected to a hydraulic motor (14). The logic element (12) is a valve which applies selective restriction in the oil passage to the preset pressure.

[0043] While operating the valve section1 (6) to open the cylinder (13) and if the cylinder (13), due to the gravitational pull, opening faster than the available pump (3) flow, cavitation occurs in the cylinder. The logical element (12) senses the same and diverts the return oil to the cylinder via the anticavitation valve (8) of the respective valve port.

[0044] While the logic element (12) applies restriction in the oil passage, the oil diverted to the cavitating side of the cylinder (13) which is a relatively at a least resistant path for the return oil flow. Because of which the cylinder (13) operation becomes faster resulting in an efficient operation. In case if the selective restriction is not applied, the oil will not get diverted to the cylinder (13) as it is not a least resistant path.

[0045] Similarly, while operating the second valve section (7) to operate the motor (14) and while the motor (14) start over running, cavitation will occur. The selective restriction made by the logical element (12) by automatically sensing the cavitation, diverts the returning oil back to the charging line to avoid cavitation and resulting in a better efficiency. While rotating the motor in clockwise direction and while cavitation occurs, through anti cavitation valve (10) oil will be regenerated. While rotating the motor in anti-clockwise direction, when cavitation occurs, the regeneration will happen through the check valve (15) in addition to the inbuilt anti-cavitation valve (11) which increases the regeneration flow of oil to further enhance the efficiency.

[0046] The below table shows the test results data in hydraulic system.

TABLE-US-00001 Test Trial Trial 1 Trial 2 Trial 3 Amb Temperature in deg C. 34.0 33.5 33.8 at test duration Engine operating speed, (RPM) 1200 1200 1200 Test duration, 20 20 20 No load pressure of pump1 (bar) 17.8 17.8 17.7 Capacity of pump1 (cc) 34.56 34.56 34.56 No load pressure of pump2 (bar) 19.8 19.8 19.8 Capacity of pump2 (cc) 16.85 16.85 16.85 Length of Trench, Meters 1 .0 14.2 13.0 Depth of Trench, 1 Meter 1.1 1.18 1.25 Width of Trench, Meters 0.90 0.90 0.90 Volume of material removed, CuM 14.85 15.08 14.63 Bucket swing angle, deg 45 60 45 60 45 60 Bucket Volume, m3 0.27 0.27 0.27 Amb Temperature in deg C. 32.8 32.8 32.5 at test duration Engine operating speed, (RPM) 1400 1400 1400 Test duration, 20 20 20 No load pressure of pump1 (bar) 18.7 18.8 18.8 Capacity of pump1 (cc) 34.56 34.56 34.56 No load pressure of pump2 (bar) 22 22 21.9 Capacity of pump2 (cc) 16.85 16.85 16.85 Length of Trench, Meters 16.2 15.8 15.5 Depth of Trench, 1 Meter 1.2 1.3 1.3 Width of Trench, Meters 0.90 0.90 0.90 Volume of material removed, CuM 17. 0 18.49 18.14 Bucket swing angle, deg 45 60 45 60 45 60 Bucket Volume, m3 0.27 0.27 0.27 Amb Temperature in deg C. 32.5 32.5 32.6 at test duration Engine operating speed, (RPM) 1600 1600 1600 Test duration, 20 20 20 No load pressure of pump1 (bar) 20 20 19.8 Capacity of pump1 (cc) 34.56 34.56 34.56 No load pressure of pump2 (bar) 23 22.8 23 Capacity of pump2 (cc) 16.85 16.85 16.85 Length of Trench, Meters 17.8 16.5 17 Depth of Trench, 1 Meter 1.2 1.28 1.25 Width of Trench, Meters 0.90 0.90 0.90 Volume of material removed, CuM 19.22 19.01 19.1 Bucket swing angle, deg 45 0 45 60 45 60 Bucket Volume, m3 0.27 0.27 0.27 indicates data missing or illegible when filed

LIST OF COMPONENTS WITH RESPECT TO REFERENCE NUMERALS

[0047] Tank (1) [0048] Strainer (2) [0049] Pump (3) [0050] Control Valve (4) [0051] Main relief valve (5) [0052] First Valve Section (6) [0053] Second Valve Section (7) [0054] Anti-cavitation cum shock relief valve (8) [0055] Anti-cavitation cum shock relief valve (9) [0056] Anti-cavitation cum shock relief valve (10) [0057] Anti-cavitation cum shock relief valve (11) [0058] Logic element (pilot operated inversely proportional valve) (12) [0059] Options for logic element/Adjustable or non-adjustable means (12a, 12b, 12c & 12d) [0060] Hydraulic Cylinder (13) [0061] Hydraulic Motor (14) [0062] Check valve (15) [0063] Sensors and Controller (16) [0064] HPCO line (17) [0065] Oil Cooler (18) [0066] Return line filter (19) [0067] Power source (20)