CN1325756C - Enclosed return circuit hydraulic beam-pumping unit utilizing frequency conversion technology - Google Patents

Abstract

The invention discloses a closed circuit hydraulic pumping unit adopting frequency conversion technology. Apply frequency conversion technology to control the speed of the motor, control the output flow of the pump, and then control the operating speed of the pumping unit, so that the pumping unit-sucker rod-pump can be dynamically coordinated, and the production increase and energy saving are obvious; the frequency conversion speed can be adjusted according to the system Need to provide flow to reduce overflow loss, no matter how the load changes, the output power can adapt to the change of load requirements, and has strong self-control. Using up and down travel switches, speed, displacement sensors, etc., through controllers, frequency converters to realize vector closed-loop control technology for motors and control valve electromagnets, etc., to achieve protection functions such as overload, over-current, over-voltage, and instantaneous stall. The present invention starts from improving the overall efficiency of the pumping unit, reduces the installed power of the pumping unit and effectively utilizes the downward energy of the pumping unit, and at the same time maximizes the efficiency of the hydraulic pump and the motor. The pumping unit can be widely used in oil production in oil fields.

Description

Closed circuit hydraulic pumping unit with frequency conversion technology

technical field

The invention relates to a device for extracting fluid from a well, in particular to a closed circuit hydraulic pumping unit using frequency conversion technology.

Background technique

At present, a kind of mechanical pumping equipment—rod pumping unit is generally used in oilfield development, which can be divided into beam pumping unit and beamless pumping unit. Beam pumping units are widely used in oil fields due to their durability, reliable components, and convenient maintenance. However, the rod pumping unit also exposed certain problems during its use:

(1) Large installed power, high energy consumption and low efficiency

Due to the large size and complex structure of the beam pumping unit, it has a large installed power. At present, the average installed capacity of pumping units in onshore oilfields is more than 32.6kw each, and the annual power consumption of rod pumping units in onshore oilfields in my country is about 6.76 billion kwh. Tracing it to its cause, because its huge balance weight, speed reducer, four-link mechanism and belt transmission mode, in the operation process, consumes a large amount of energy. In addition, the electric motor cannot automatically adjust its output power according to the load change of the pumping unit's up and down strokes, so the system efficiency of the pumping unit is very low, only about 26%.

(2) Poor automatic control performance

The working conditions of the oil well are complex and changeable, and the current mechanical beam pumping unit cannot adjust its motion law in real time according to the actual working conditions to meet the technical requirements of different strokes and stroke times of the oil well. Problems such as insufficient fluid supply and reduced pump efficiency of the pumping unit cannot be solved. It is also impossible to automatically diagnose and control oil well failures, so many failures (such as sucker rods or pump breakage, etc.) cannot be discovered and avoided in time, thereby affecting production and causing unnecessary waste.

In order to solve the above problems, people apply hydraulic technology on the pumping unit. The parameters of the hydraulic pumping unit are convenient to adjust, easy to realize stepless speed regulation, and can well adapt to changes in well conditions. And it is easy to realize the long stroke and low stroke times of the pumping unit, so that the overall weight and floor area of the pumping unit are greatly reduced.

In recent years, as my country's oilfields increasingly need long-stroke, low-stroke pumping units to increase fluid production, people have studied a variety of energy-saving hydraulic pumping units, which are improving oil pumping Some progress has been made in improving the efficiency of the pumping unit, but the design of the hydraulic system is mostly based on how to recover the energy of the downstroke of the pumping unit, and does not make full use of the motor and hydraulic pump. At the same time, the self-adaptive ability of the pumping unit is poor, resulting in low system efficiency, and the energy-saving effect of the pumping unit is not obvious, so it has not been effectively promoted.

Contents of the invention

In order to overcome the above-mentioned shortcomings of high energy consumption, low efficiency and poor self-control, the object of the present invention is to provide a closed circuit hydraulic pumping unit with frequency conversion technology that reduces installed power.

The technical solution adopted by the present invention to solve its technical problems is:

Option 1: A closed circuit hydraulic pumping unit using frequency conversion technology, which consists of three parts: mechanical, hydraulic and electronic control:

1) Mechanical part: the upper and lower pistons of the hydraulic cylinder plunger are matched with the hydraulic cylinder, a hydraulic cylinder partition is installed between the two pistons, the fixed pin and the roller bracket connect the end of the hydraulic cylinder plunger with the movable pulley, and the movable pulley is wound with a steel wire rope , one end of the wire rope is connected to the fixed base frame, the other end is connected to the polished rod of the pumping unit, and the polished rod of the pumping unit is connected to the oil suction pipe through the Christmas tree;

2) Hydraulic part: One end of the two-way pump/motor is connected to the upper piston oil chamber of the hydraulic cylinder through the first hydraulic line through the first hydraulic control check valve, and the other end is through the second hydraulic line through the second hydraulic control check valve It is connected with the upper piston of the hydraulic cylinder and the oil chamber between the hydraulic cylinder partition to form a closed loop main hydraulic pipeline; the hydraulically controlled three-position four-way edge valve is connected with an oil inlet and a The control oil port, the oil inlet at the end of the high-pressure selection shuttle valve connected to the first hydraulic pipeline, and the oil outlet of the first check valve are simultaneously connected with the oil inlet of the first hydraulic control check valve; the hydraulic control three-position An oil inlet and a control oil port at the other end of the four-way edge valve connected to the second hydraulic pipeline, an oil inlet at the other end of the high-pressure selection shuttle valve connected to the second hydraulic pipeline, and the first one-way valve The oil outlet of the second one-way valve connected in series is connected with the oil inlet of the second hydraulically controlled one-way valve at the same time; The series connection point of the second one-way valve and the oil inlet of the first safety relief valve, the oil inlet of the second safety relief valve The oil outlet of the first safety relief valve is connected to the oil tank through the cooler and the spring-loaded check valve respectively; the oil inlet of the third safety relief valve is connected to an oil outlet of the high pressure selection shuttle valve, The oil outlet of the third safety relief valve is connected to the series connection point of the first check valve and the second check valve; the other oil outlet of the high pressure selection shuttle valve is connected to the oil inlet of the electromagnetic reversing valve through the control oil hydraulic pipeline The oil outlet of the electromagnetic reversing valve is connected to the control oil ports of the first hydraulic control check valve and the second hydraulic control check valve respectively through the control oil hydraulic pipeline; the oil inlet of the quantitative pump is connected to the oil tank, and the quantitative pump The oil outlet of the hydraulic cylinder is respectively connected to the rodless oil chamber of the hydraulic cylinder, the accumulator, and the oil inlet of the fourth safety relief valve through the third one-way valve, and the oil outlet of the fourth safety relief valve is connected to the oil tank; The oil chamber between the lower piston of the cylinder and the diaphragm of the hydraulic cylinder is connected with the oil tank;

3) Electronic control part: The five signal input ports of the controller are respectively connected to the speed-displacement sensor, the protection switch of the upper and lower limit positions of the sucker rod, and the travel switch of the upper and lower positions through five signal lines, and the first signal output port of the controller is connected through The sixth signal line is connected to the electromagnet control line of the electromagnetic reversing valve, the second signal output port of the controller is connected to one signal input port of the frequency converter through the seventh signal line, and the other signal input port of the frequency converter is connected to the photoelectric The encoder is connected, and the signal output port of the frequency converter is connected with the motor of the bidirectional pump/motor through another signal line.

Scheme 2: Another closed-loop hydraulic pumping unit using frequency conversion technology, which consists of three parts: mechanical, hydraulic and electronic control:

1) Mechanical part: the upper and lower pistons of the hydraulic cylinder plunger are matched with the hydraulic cylinder, a hydraulic cylinder partition is installed between the two pistons, fixed pulleys are installed on the fixed base frame, the fixed pin and the roller bracket hold the end of the hydraulic cylinder plunger It is connected with the movable pulley, and the steel wire rope is wound on the movable pulley. One end of the steel wire rope is connected to the fixed base frame, and the other end is connected to the polished rod of the pumping unit through the fixed pulley. The polished rod of the pumping unit is connected to the oil suction pipe through the Christmas tree;

2) Hydraulic part: One end of the two-way pump/motor is connected to the upper piston oil chamber of the hydraulic cylinder through the first hydraulic line through the first hydraulic control check valve, and the other end is through the second hydraulic line through the second hydraulic control check valve It is connected with the upper piston of the hydraulic cylinder and the oil chamber between the hydraulic cylinder partition to form a closed loop main hydraulic pipeline; the hydraulically controlled three-position four-way edge valve is connected with an oil inlet and a The control oil port, the oil inlet at the end of the high-pressure selection shuttle valve connected to the first hydraulic pipeline, and the oil outlet of the first check valve are simultaneously connected with the oil inlet of the first hydraulic control check valve; the hydraulic control three-position An oil inlet and a control oil port at the other end of the four-way edge valve connected to the second hydraulic pipeline, an oil inlet at the other end of the high-pressure selection shuttle valve connected to the second hydraulic pipeline, and the first one-way valve The oil outlet of the second one-way valve connected in series is connected with the oil inlet of the second hydraulically controlled one-way valve at the same time; The series connection point of the second one-way valve and the oil inlet of the first safety relief valve, the oil inlet of the second safety relief valve The oil outlet of the first safety relief valve is connected to the oil tank through the cooler and the spring-loaded check valve respectively; the oil inlet of the third safety relief valve is connected to an oil outlet of the high pressure selection shuttle valve, The oil outlet of the third safety relief valve is connected to the series connection point of the first check valve and the second check valve; the other oil outlet of the high pressure selection shuttle valve is connected to the oil inlet of the electromagnetic reversing valve through the control oil hydraulic pipeline The oil outlet of the electromagnetic reversing valve is connected to the control oil ports of the first hydraulic control check valve and the second hydraulic control check valve respectively through the control oil hydraulic pipeline; the oil inlet of the quantitative pump is connected to the oil tank, and the quantitative pump The oil outlet of the hydraulic cylinder is respectively connected with the oil chamber between the lower piston of the hydraulic cylinder and the diaphragm of the hydraulic cylinder, the accumulator, and the oil inlet of the fourth safety relief valve through the third check valve. The oil outlet is connected to the oil tank; the rodless oil chamber of the hydraulic cylinder is connected to the oil tank;

3) Electronic control part: The five signal input ports of the controller are respectively connected with the speed-displacement sensor, the protection switch of the upper and lower limit positions of the sucker rod, and the travel switch of the upper and lower positions through five signal lines, and the first signal output port of the controller is connected through The sixth signal line is connected to the electromagnet control line of the electromagnetic reversing valve, the second signal output port of the controller is connected to one signal input port of the frequency converter through the seventh signal line, and the other signal input port of the frequency converter is connected to the photoelectric The encoder is connected, and the signal output port of the frequency converter is connected with the motor of the bidirectional pump/motor through another signal line.

Compared with the background technology, the present invention has the beneficial effects that: the present invention uses frequency conversion technology to control the rotational speed of the three-phase asynchronous motor, thereby controlling the output flow of the pump, achieving the control of the hydraulic cylinder according to a certain rule, and then the operation of the hydraulic pumping unit The purpose of speed is to make the pumping unit-sucker rod-sucker pump can be dynamically coordinated, increase production and save energy significantly; frequency conversion speed regulation can provide flow according to the needs of the system so as to minimize the loss of system overflow, so this No matter how the load changes, the output power of the system can adapt to the change of load requirements, and has strong self-control. The present invention uses electronic control equipment such as up and down stroke switches, speed and displacement sensors, and realizes vector closed-loop control technology for motors and control valve electromagnets through controllers and frequency converters, thereby realizing overload, overcurrent, overvoltage, and instantaneous stall. And many other strong protection functions. The present invention makes full use of the advantages of the hydraulic system itself, and starts from improving the overall efficiency of the pumping unit, while reducing the installed power of the pumping unit and effectively utilizing the downward energy of the pumping unit, it maximizes the efficiency of the hydraulic pump and the motor. efficiency. In a word, this hydraulic pumping unit combines the contemporary hydraulic volume speed regulation technology, computer technology, frequency conversion control technology, rich software and hardware resources, flexible system control, so that it has the advantages of simple structure, remarkable energy saving effect and strong adaptability. The pumping unit can be widely used in oil production in oil fields.

Description of drawings

The present invention will be further described below in conjunction with drawings and embodiments.

Fig. 1 is a kind of structural schematic diagram of the present invention;

Fig. 2 is a schematic diagram of another structural principle of the present invention.

In the figure: 1. Fuel tank, 2. Hydraulic pipeline, 3. Quantitative pump, 4. Coupling, 5. Motor, 6. Check valve, 7. Hydraulic pipeline, 8. Accumulator, 9. Safety overflow Flow valve, 10, 11, 12. Hydraulic line, 13. Cooler, 14, 16, 17, 18. Hydraulic line, 15. Spring loaded check valve, 19. Safety relief valve, 20, 21. Hydraulic pipeline, 22. Motor, 23. Coupling, 24. Bidirectional pump/motor, 25. Photoelectric encoder, 26. Charge pump, 27. Motor, 28. Coupling, 29. Hydraulic pipeline, 30. Signal line, 31, 32, 33. Hydraulic pipeline, 34, 35. Check valve, 36. Hydraulic pipeline, 37. Safety overflow valve, 38. Hydraulic pipeline, 39. High pressure selection shuttle valve, 40, 41 , 42, 43, 44. Hydraulic pipelines, 45. Hydraulic control three-position four-way edge valve, 46, 47. Hydraulic pipelines, 48. Safety relief valves, 49, 50, 51, 53. Hydraulic pipelines, 52, 54, 55. Hydraulic pipelines flowing through control oil, 56, 57. Hydraulic control check valves, 58. Electromagnetic reversing valves, 59, 60. Hydraulic pipelines, 61. Seal rings, 62, 65. respectively It is the protection switch of the upper and lower limit positions of the sucker rod, 63, 64 are the travel switches of the upper and lower positions respectively, 66. the iron stopper at the upper end of the plunger, 67. the fixed base frame, 68. the signal line, 69. the frequency converter , 70, 71. Signal line, 72. Controller, 73, 74, 75, 76, 77. Signal line, 78. Moving pulley, 79. Wire rope, 80. Roller bracket, 81. Fixed pin, 82. Hydraulic cylinder plunger , 83. Hydraulic cylinder, 84. Speed-displacement sensor, 85. Pumping unit polished rod, 86. Hydraulic cylinder partition, 87. Christmas tree, 88. Oil extraction pipe, 89. Fixed ground, 90. Fixed pulley. Among them, the dotted lines 52, 54, 55 are the contents of the hydraulic part, indicating that the flow in the hydraulic pipeline is the control oil, and the dotted lines 30, 68, 70, 71, 73, 74, 75, 76, 77 are the contents of the electronic control part, indicating that each An electrical control signal.

Detailed ways

As shown in Figure 1, the present invention includes:

Mechanical part: the upper and lower pistons of the hydraulic cylinder plunger 82 match the hydraulic cylinder 83, a hydraulic cylinder partition 86 is installed between the two pistons, the fixed pin 81 and the roller bracket 80 connect the end of the hydraulic cylinder plunger 82 with the movable pulley 78 , the movable pulley 78 is wound with a wire rope 79, one end of the wire rope 79 is connected to the fixed base frame 67, the other end is connected to the polished rod 85 of the pumping unit, and the polished rod 85 of the pumping unit is connected to the oil extraction pipe 88 through the christmas tree 87.

Hydraulic part: One end of the two-way pump/motor 24 is connected to the oil inlet of the first hydraulic control check valve 56 through the hydraulic pipeline 31, and then connected to the upper piston oil chamber 83A of the hydraulic cylinder 83 through the hydraulic pipeline 59, and the other end is The hydraulic pipeline 42 is connected to the oil inlet of the second hydraulic control check valve 57, and then connected to the oil cavity 83B between the upper piston of the hydraulic cylinder 83 and the hydraulic cylinder partition 86 through the hydraulic pipeline 60, forming a closed loop The main hydraulic pipeline; an oil inlet at one end of the hydraulically controlled three-position four-way edge valve 45 is connected to the hydraulic pipeline 31 at the oil inlet end of the first hydraulically controlled check valve 56 through the hydraulic pipeline 43, and the hydraulically controlled three-position four-way A control oil port of the through rib valve 45 is connected with the hydraulic line 31 of the oil inlet end of the first hydraulic control check valve 56 through the hydraulic pipeline 46, and an oil inlet at one end of the high-pressure selection shuttle valve 39 is connected through the hydraulic pipeline 40 It is connected with the hydraulic pipeline 31 of the oil inlet port of the first hydraulically controlled check valve 56, and the oil outlet port of the first check valve 34 is hydraulically connected with the oil inlet port of the first hydraulically controlled check valve 56 through the hydraulic pipeline 32. The pipeline 31 is connected; an oil inlet at the other end of the hydraulically controlled three-position four-way edge valve 45 is connected with the hydraulic pipeline 42 at the oil inlet end of the second hydraulically controlled check valve 57 through the hydraulic pipeline 44, and the hydraulically controlled three-position A control port of the four-way edge valve 45 is connected to the hydraulic line 42 of the oil inlet end of the second hydraulic control check valve 57 through the hydraulic line 47, and the oil inlet at the other end of the high-pressure selection shuttle valve 39 is connected through the hydraulic line. 41 is connected with the hydraulic pipeline 42 of the oil inlet port of the second hydraulic control check valve 57, and the oil outlet of the second check valve 35 connected in series with the first check valve 34 is connected with the second hydraulic control valve through the hydraulic pipeline 33. The oil inlet end of the one-way valve 57 is connected to the hydraulic pipeline 42; the oil inlet of the charge pump 26 is connected to the oil tank 1 through the hydraulic pipeline 21, and the other end is connected to the first one-way valve 34 and the second one-way valve through the hydraulic pipeline 29 respectively. The oil inlet of the second safety relief valve 48 is connected to the oil inlet of the hydraulically controlled three-position four-way edge valve 45 through the hydraulic pipelines 29 and 20. The oil outlet of the oil port and the second safety relief valve 48 is connected to the oil outlet end of the first safety relief valve 19 through the hydraulic pipeline 17, and then through the hydraulic pipeline 18, the cooler 13, the hydraulic pipeline 12 or through the hydraulic pipeline 17. The oil tank 1 is connected behind the hydraulic pipeline 14, the spring-loaded check valve 15, and the hydraulic pipeline 16; the oil inlet of the third safety overflow valve 37 is connected to an oil outlet of the high-pressure selection shuttle valve 39 through the hydraulic pipeline 38, The oil outlet of the third safety relief valve 37 is connected to the series connection point of the first check valve 34 and the second check valve 35 through the hydraulic pipeline 36; the other oil outlet of the high pressure selection shuttle valve 39 is connected through the control oil hydraulic pipeline 52 is connected with the oil inlet port of the electromagnetic reversing valve 58, and the oil outlet port of the electromagnetic reversing valve 58 is connected with the control oil port of the first hydraulic control check valve 56 through the control oil hydraulic pipeline 54, and is connected with the control oil hydraulic pipeline through the control oil hydraulic pipeline. 55 is connected to the control oil port of the second hydraulic control check valve 57; the oil inlet port of the quantitative pump 3 is connected to the oil tank 1 through the hydraulic pipeline 2, and the oil outlet port of the quantitative pump 3 passes through the third check valve 6 respectively through the hydraulic pipe The road 7 is connected with the rodless oil chamber 83D of the hydraulic cylinder 83, connected with the accumulator 8 through the hydraulic pipeline 51, connected with the oil inlet of the fourth safety overflow valve 9 through the hydraulic pipeline 50, and the fourth safety overflow valve The oil outlet of the valve 9 is connected to the oil tank 1 through the hydraulic pipeline 10; the oil cavity 83C between the lower piston of the hydraulic cylinder 83 and the hydraulic cylinder partition 86 is connected to the oil tank 1 through the hydraulic pipeline 11.

Electronic control part: the five signal input ports of the controller 72 are respectively connected with the speed-displacement sensor 84, the protection switches 62 and 65 of the upper and lower limit positions of the sucker rod through five signal lines 73, 74, 77, 75, and 76, The upper and lower position travel switches 63 and 64 are connected, the first signal output port of the controller 72 is connected with the electromagnet control line of the electromagnetic reversing valve 58 through the sixth signal line 68, and the second signal output port of the controller 72 is connected through the seventh signal The line 71 is connected with one signal input port of the frequency converter 69, the other signal input port of the frequency converter 69 is connected with the photoelectric encoder 25 through the signal line 30, and the signal output port of the frequency converter 69 is connected with the bidirectional pump/motor 24 through another signal line 70 The motor 22 is connected.

The difference between Fig. 2 and Fig. 1 is: in Fig. 2, its mechanical part: the upper and lower pistons of the hydraulic cylinder plunger 82 are matched with the hydraulic cylinder 83, and a hydraulic cylinder partition 86 is installed between the two pistons, and the fixed base The fixed pulley 90 is housed on the frame 67, the fixed pin 81 and the roller bracket 80 connect the end of the hydraulic cylinder plunger 82 with the movable pulley 78, the movable pulley 78 is wound with a steel wire rope 79, one end of the steel wire rope 79 is connected to the fixed base frame 67, and the other end passes through the fixed pulley 90 Connect the polished rod 85 of the pumping unit, and the polished rod 85 of the pumping unit is connected to the oil extraction pipe 88 through the Christmas tree 87 . The connection modes of the above-mentioned hydraulic parts are basically the same, the difference is that in Fig. 2, the outlet of the accumulator 8 communicates with the oil chamber 83C between the lower piston of the hydraulic cylinder 83 and the hydraulic cylinder partition 86 through the hydraulic pipelines 51 and 7, so as to To realize its counterweight balance function; the rodless oil cavity 83D of the hydraulic cylinder 83 is connected with the oil tank 1 through the hydraulic pipeline 11 .

Since the principles of the hydraulic part and the electric control part of the two schemes are basically the same, the working process principle of the closed circuit hydraulic pumping unit energy-saving system scheme 1 is mainly explained as follows:

(1) The plunger goes up

When the pumping unit is on an upstroke, the controller 72 outputs a control signal 71 to the frequency converter 69, and the frequency converter 69 drives the motor 22 to run at a low speed through the control signal 70; at the same time, the controller 72 outputs a control signal 68 to turn the electromagnetic reversing valve 58 to the right position The electric motor 22 drives the two-way pump/motor 24 through the shaft coupling 23, and outputs high-pressure oil in the hydraulic pipeline 42, and passes through the hydraulic pipeline 42, through the hydraulic control check valve 57, into the upper piston of the hydraulic cylinder 83 and the hydraulic cylinder The oil chamber 83B between the partitions 86; at this time, the high-pressure oil in the hydraulic line 42 passes through the hydraulic line 41, the high-pressure selection shuttle valve 39, and enters the hydraulic line 52 as control oil, and passes through the right position of the electromagnetic reversing valve 58, the hydraulic pressure The pipeline 54 reaches the hydraulic control check valve 56, and the hydraulic control check valve 56 is opened, so the oil flowing out of the upper piston oil chamber 83A of the hydraulic cylinder 83 can pass through the hydraulic control check valve 56 smoothly; enter the hydraulic cylinder The high-pressure oil in the oil chamber 83B between the upper piston of 83 and the hydraulic cylinder partition 86 pushes the plunger 82 upward, drives the movable pulley 78 upward, and then drives the sucker rod 85 upward; during the upward movement of the piston 82, the upward movement of the hydraulic cylinder 83 The oil in the oil chamber 83B between the piston and the hydraulic cylinder partition 86 is discharged, and is sucked into the two-way pump/motor 24 again through the hydraulic pipeline 59, the hydraulic control check valve 56, and the hydraulic pipeline 31. The hydraulic oil discharged from the oil chamber 83C between the lower piston and the hydraulic cylinder partition 86 is directly returned to the oil tank through the hydraulic pipeline 11; The rodless oil chamber 83D of the cylinder 83 supplies oil to the rodless oil chamber 83D of the hydraulic cylinder 83. On the other hand, the accumulator 8 communicates with the rodless oil chamber 83D of the hydraulic cylinder 83 through the hydraulic pipelines 51 and 7, so that the hydraulic pressure The rodless oil chamber 83D of the cylinder 83 maintains a certain constant pressure, which can be used to balance a part of the load and play the role of counterweight. During operation, the control controller 72 detects the signal 73 output by the speed-displacement sensor 84 in real time, and calculates the operating speed and displacement of the pumping unit at this time; the frequency converter 69 detects the signal 30 output by the photoelectric encoder 25, and calculates this When the speed of the motor 22. In the controller 72, the input displacement signal is compared with the preset stroke, and the input speed signal is compared with the ideal operating speed curve, and the control signal 71 is continuously output to the frequency converter 69, so that the frequency converter continuously outputs signals 70 to adjust the rotation speed of the motor 22, change the oil flow into the hydraulic cylinder 83, and then continuously adjust the operating speed of the sucker rod 85 to make it run in the most ideal working state. When the displacement of the sucker rod is close to the set stroke, the stopper 66 at the upper end of the plunger touches the upper position travel switch 63, making it generate a control signal 75 to the controller 72, and the controller 72 sends a control signal 71 to the frequency converter 69, and the frequency converter 69 reduces the rotation speed of the motor 22 through the control signal 70, so that the oil supply of the bidirectional pump/motor 24 is reduced until the rotation speed of the motor 22 becomes zero, and there is no flow output. The control oil pressure of 56 drops to zero, so that the hydraulic cylinder 83 is locked in a fixed position, stops moving, and the speed of the sucker rod 85 becomes zero; after the sucker rod 85 reaches the upstroke position, it will stay for a period of time according to the ideal speed curve. The deformation energy of the sucker rod 85 is released, and at this time, its reliable stop is realized by the above-mentioned locking circuit.

(2) The plunger goes down

During the downstroke of the pumping unit, the controller 72 outputs a control signal 71 to the frequency converter 69, and the frequency converter 69 drives the motor 22 to run in reverse at a low speed through the control signal 70; at the same time, the controller 72 outputs a control signal 68 to turn the electromagnetic reversing valve 58 on. to the right position; the motor 22 drives the two-way pump/motor 24 through the coupling 23, and outputs high-pressure oil to the hydraulic pipeline 31, through the hydraulic pipeline 31, through the hydraulic control check valve 56 and the hydraulic pipeline 59, into the hydraulic cylinder 83 in the upper piston oil chamber 83A; at this time, the high-pressure oil in the hydraulic line 31 passes through the hydraulic line 40, the high-pressure selection shuttle valve 39, enters the hydraulic line 52 as control oil, and passes through the electromagnetic reversing valve 58 to the right, hydraulic pressure The pipelines 54 and 55 reach the hydraulically controlled one-way valve 57, and the hydraulically controlled one-way valve 57 is opened, so the oil flowing out of the oil chamber 83B between the upper piston of the hydraulic cylinder 83 and the hydraulic cylinder partition 86 can pass through smoothly. The hydraulic control check valve 57; the high-pressure oil entering the upper piston oil chamber 83A of the hydraulic cylinder 83 pushes the plunger 82 of the hydraulic cylinder 83 downward, drives the roller 78 downward, and then drives the sucker rod 85 downward; during the downward process of the piston 82 , the oil in the oil chamber 83B between the upper piston of the hydraulic cylinder 83 and the hydraulic cylinder partition 86 is discharged, and is sucked into the two-way pump/motor 24 again through the hydraulic pipeline 60, the hydraulic control check valve 57, and the hydraulic pipeline 42. In the process, the pressure in the upper piston oil chamber 83A of the hydraulic cylinder 83 is used, and the energy is used to make the piston 82 move downward through the downstroke of the pumping unit, and a part of the energy is passed through the rodless oil chamber 83D of the hydraulic cylinder 83 through the hydraulic pipe. The channels 7 and 51 are recovered into the accumulator 8 for energy storage; the oil cavity 83C between the lower piston of the hydraulic cylinder 83 and the hydraulic cylinder partition 86 produces a self-priming effect due to its larger volume, and is connected to the hydraulic pressure through the hydraulic pipeline 11. Cylinder 1 sucks oil into the oil cavity 83C between the lower piston of the hydraulic cylinder 83 and the hydraulic cylinder partition 86 to replenish oil. During operation, the controller 72 detects the signal 73 output by the speed-displacement sensor 84 in real time, and calculates the operating speed and displacement of the pumping unit at this time; the frequency converter 69 detects the signal 30 output by the photoelectric encoder 25, and calculates the current The speed of the motor 22; in the controller 72, the input displacement signal is compared with the preset stroke, and after the input speed signal is compared with the ideal running speed curve, the control signal 71 is continuously output to the frequency converter 69, so that The frequency converter continuously outputs the signal 70 to adjust the speed of the motor 22, change the oil flow in the output hydraulic cylinder 83, and then continuously adjust the running speed of the sucker rod 85 to run it in the most ideal working state. When the displacement of the sucker rod is close to the set stroke, the stopper 66 at the upper end of the plunger touches the travel switch 64 at the lower position, making it generate a control signal 76 to the controller 72, and the controller 72 sends a control signal 71 to the frequency converter 69, and the frequency converter 69 reduces the rotation speed of the motor 22 through the control signal 70, so that the oil supply of the bidirectional pump/motor 24 is reduced until the rotation speed of the motor 22 becomes zero, and there is no flow output. The control oil pressure of 57 drops to zero, so that the hydraulic cylinder 83 is locked in a fixed position, stops moving, and the speed of the sucker rod 85 becomes zero; after the sucker rod 85 reaches the downstroke position, it will also stay for a period of time according to the ideal speed curve , so that the filling factor of the oil well pump can be optimized.

The principle of scheme 2 of energy-saving system of closed circuit hydraulic pumping unit is basically the same as that of scheme 1. The difference is that the downward process of the plunger in scheme 2 is just the upstroke process of the pumping unit, and the upward stroke of the plunger is the downstroke process of the pumping unit. .

During the up and down operation of the pumping unit, the speed and position signals of the pumping unit are fed back to the controller 72 in real time and recorded, and compared with the ideal operating curve set in the controller 72, a large closed loop of pumping unit speed feedback is formed , so as to adjust and control the speed of the pumping unit in real time, so that it can reach the best oil recovery state. During the operation of the pumping unit, the motor can continuously adjust its output power according to the change of the load, thereby saving a lot of energy.

Input the required pumping unit stroke and number of strokes to the controller 72, the controller 72 will automatically adjust the flow of oil flowing into and out of the hydraulic cylinder 83, thereby adjusting the stroke times of the pumping unit; The speed and displacement sensors of the pumping machine can automatically adjust the stroke of the pumping unit.

Since the pumping unit works frequently on the up and down strokes, the temperature rise of the oil in the system is relatively large, so a cooling system must be used. This system uses a charge pump 26 to force the closed circuit to cool the circuit to achieve a good cooling effect.

This system adopts a closed hydraulic circuit system, so that the two working chambers of the hydraulic cylinder 83 are the upper piston oil chamber 83A of the hydraulic cylinder 83, and the oil in the oil chamber 83B between the upper piston of the hydraulic cylinder 83 and the hydraulic cylinder partition 86 It is effectively utilized, which greatly saves the amount of hydraulic oil used. At the same time, the system has a compact structure and strong safety.

This system uses a locking circuit to realize the stop of the pumping unit at the end of the stroke, which has the characteristics of fast response, safe and reliable locking.

The energy accumulator 8 is used as configuration, so that the installed power of the system is greatly reduced. The accumulator 8 generates a certain amount of pressure oil to act on the plunger rod 82 of the hydraulic cylinder 83, so that when the sucker rod 85 is upstroke, its force offsets a part of the gravity of the sucker rod 85 to push the sucker rod 85 upward; During the downstroke of the oil rod 85, its active force can still be used to offset a part of the gravity of the sucker rod to realize its counterweight function, and can also be used to reclaim the energy during the downstroke of the pumping unit to realize energy reuse. The accumulator 8 also plays the role of buffering the mechanical shock at the end of the upper and lower strokes, so that the operation effect of the pumping unit is more stable.

When the plunger 82 of the hydraulic cylinder 83 rushes out of its prescribed stroke due to an accident, the iron stopper at the upper end of the plunger rod 82 will contact the protection switches 62, 65 at the upper and lower limit positions, forcing the system to be powered off to realize power-off protection.

Among the other components of the system, when the speed-displacement sensor 84 detects that the sucker rod 85 has an unexpected excessive speed during the operation of the pumping unit, the controller 72 will generate a control signal 68 to make the electromagnetic reversing valve 58 switch to Left position, the control oil pressure of hydraulic control check valve 56, 57 is zero, forms self-locking loop, realizes hydraulic cylinder 83 oil circuit locking, makes pumping unit brake safely. During the upstroke of the pumping unit, due to overload, the outlet pressure of the two-way pump/motor 24 will rise, and at this time the safety relief valve 37 will open quickly to realize the overflow of the closed circuit from the high-pressure pipeline to the low-pressure pipeline Protection, keeping the pressure at the upper limit of the working pressure and preventing it from continuing to rise. It can be seen that the system has multiple protection functions in terms of safety and reliability.

Claims (2)

1. closed circuit hydraulic pumping unit that adopts converter technique is characterized in that being made up of machinery, hydraulic pressure, automatically controlled three parts:

1) mechanical part: two pistons up and down and the hydraulic cylinder (83) of cylinder plunger (82) match, two piston spaces are equipped with hydraulic cylinder dividing plate (86), steady pin (81) is connected cylinder plunger (82) end with rolling wheel support (80) with movable pulley (78), movable pulley (78) is gone up around wire rope (79), wire rope (79) one ends are connected and fixed pedestal (67), the other end connects oil-extractor polish-rod (85), and oil-extractor polish-rod (85) connects oil pick-up tube (88) through production tree (87);

2) hydraulic part: two-way pump/motor (24) one ends link to each other with the upper piston oil pocket (83A) of hydraulic cylinder (83) by first hydraulic control one-way valve (56) through first fluid pressure line, the other end links to each other with oil pocket (83B) between hydraulic cylinder dividing plate (86) by second hydraulic control one-way valve (57) and the upper piston of hydraulic cylinder (83) through second fluid pressure line, forms a closed circuit master fluid pressure line; Link to each other oil-in and a control port, the high pressure of an end of hydraulic control 3-position 4-way rib valve (45) and first fluid pressure line selects link to each other with first fluid pressure line oil-in of an end and the oil-out of first one way valve (34) of shuttle valve (39) to be connected with the oil-in of first hydraulic control one-way valve (56) simultaneously; An oil-in of the other end that hydraulic control 3-position 4-way rib valve (45) links to each other with second fluid pressure line selects the oil-in of the continuous other end of the shuttle valve (39) and second fluid pressure line and second one way valve (35) oil-out of first one way valve (34) serial connection to be connected with the oil-in of second hydraulic control one-way valve (57) simultaneously with a control port, high pressure; The oil-in connected tank (1) of slippage pump (26), the oil-out of slippage pump (26) connects respectively that first one way valve (34) is connected in series a little with second one way valve (35) and the oil-in of first safety overflow valve (19), the oil-in of second safety overflow valve (48) connects hydraulic control 3-position 4-way rib valve (45) oil-out, and the oil-out that the oil-out of second safety overflow valve (48) connects first safety overflow valve (19) is connected tank (1) behind cooler (13), spring-loaded one way valve (15) respectively again; The oil-in of the 3rd safety overflow valve (37) is connected on the oil-out that high pressure is selected shuttle valve (39), and the oil-out of the 3rd safety overflow valve (37) connects first one way valve (34) and is connected in series a little with second one way valve (35); High pressure selects another oil-out of shuttle valve (39) to link to each other with the oil-in of solenoid operated directional valve (58) through control fluid pressure pipe road, and the oil-out of solenoid operated directional valve (58) links to each other with the control port of first hydraulic control one-way valve (56) with second hydraulic control one-way valve (57) respectively through control fluid pressure pipe road; The oil-in connected tank (1) of constant displacement pump (3), the oil-out of constant displacement pump (3) is connected the oil-out connected tank (1) of the 4th safety overflow valve (9) with the oil-in of the no bar oil pocket (83D) of hydraulic cylinder (83), accumulator (8), the 4th safety overflow valve (9) respectively by the 3rd one way valve (6); The lower piston of hydraulic cylinder (83) links to each other with fuel tank (1) with oil pocket (83C) between hydraulic cylinder dividing plate (86);

3) automatically controlled part: five signal inputs of controller (72) are by five signal line (73; 74; 77; 75; 76) respectively with speed one displacement transducer (84); the protection switch (62 of the high-low limit position of sucker rod; 65); upper-lower position travel switch (63; 64) link to each other; controller (72) first signal outputs link to each other with the magnet control line of solenoid operated directional valve (58) by the 6th holding wire (68); controller (72) secondary signal delivery outlet links to each other with a signal input of frequency converter (69) by the 7th holding wire (71); another signal input of frequency converter (69) links to each other with photoelectric encoder (25) by holding wire (30), and frequency converter (69) signal output links to each other with the motor (22) of two-way pump/motor (24) by another holding wire (70).

2. closed circuit hydraulic pumping unit that adopts converter technique is characterized in that being made up of machinery, hydraulic pressure, automatically controlled three parts:

1) mechanical part: two pistons up and down and the hydraulic cylinder (83) of cylinder plunger (82) match, two piston spaces are equipped with hydraulic cylinder dividing plate (86), fixed pulley (90) is housed on the stationary base mount (67), steady pin (81) is connected cylinder plunger (82) end with rolling wheel support (80) with movable pulley (78), movable pulley (78) is gone up around wire rope (79), wire rope (79) one ends are connected and fixed pedestal (67), the other end connects oil-extractor polish-rod (85) through fixed pulley (90), and oil-extractor polish-rod (85) connects oil pick-up tube (88) through production tree (87);

2) hydraulic part: two-way pump/motor (24) one ends link to each other with the upper piston oil pocket (83A) of hydraulic cylinder (83) by first hydraulic control one-way valve (56) through first fluid pressure line, the other end links to each other with oil pocket (83B) between hydraulic cylinder dividing plate (86) by second hydraulic control one-way valve (57) and the upper piston of hydraulic cylinder (83) through second fluid pressure line, forms a closed circuit master fluid pressure line; Link to each other oil-in and a control port, the high pressure of an end of hydraulic control 3-position 4-way rib valve (45) and first fluid pressure line selects link to each other with first fluid pressure line oil-in of an end and the oil-out of first one way valve (34) of shuttle valve (39) to be connected with the oil-in of first hydraulic control one-way valve (56) simultaneously; An oil-in of the other end that hydraulic control 3-position 4-way rib valve (45) links to each other with second fluid pressure line selects the oil-in of the continuous other end of the shuttle valve (39) and second fluid pressure line and second one way valve (35) oil-out of first one way valve (34) serial connection to be connected with the oil-in of second hydraulic control one-way valve (57) simultaneously with a control port, high pressure; The oil-in connected tank (1) of slippage pump (26), the oil-out of slippage pump (26) connects respectively that first one way valve (34) is connected in series a little with second one way valve (35) and the oil-in of first safety overflow valve (19), the oil-in of second safety overflow valve (48) connects hydraulic control 3-position 4-way rib valve (45) oil-out, and the oil-out that the oil-out of second safety overflow valve (48) connects first safety overflow valve (19) is connected tank (1) behind cooler (13), spring-loaded one way valve (15) respectively again; The oil-in of the 3rd safety overflow valve (37) is connected on the oil-out that high pressure is selected shuttle valve (39), and the oil-out of the 3rd safety overflow valve (37) connects first one way valve (34) and is connected in series a little with second one way valve (35); High pressure selects another oil-out of shuttle valve (39) to link to each other with the oil-in of solenoid operated directional valve (58) through control fluid pressure pipe road, and the oil-out of solenoid operated directional valve (58) links to each other with the control port of first hydraulic control one-way valve (56) with second hydraulic control one-way valve (57) respectively through control fluid pressure pipe road; The oil-in connected tank (1) of constant displacement pump (3), the oil-out of constant displacement pump (3) by the 3rd one way valve (6) respectively with the lower piston of hydraulic cylinder (83) and hydraulic cylinder dividing plate (86) between oil pocket (83C), accumulator (8), the oil-in of the 4th safety overflow valve (9) be connected the oil-out connected tank (1) of the 4th safety overflow valve (9); The no bar oil pocket (83D) of hydraulic cylinder (83) links to each other with fuel tank (1);

3) automatically controlled part: five signal inputs of controller (72) are by five signal line (73; 74; 77; 75; 76) respectively with speed-displacement transducer (84); the protection switch (62 of the high-low limit position of sucker rod; 65); upper-lower position travel switch (63; 64) link to each other; controller (72) first signal outputs link to each other with the magnet control line of solenoid operated directional valve (58) by the 6th holding wire (68); controller (72) secondary signal delivery outlet links to each other with a signal input of frequency converter (69) by the 7th holding wire (71); another signal input of frequency converter (69) links to each other with photoelectric encoder (25) by holding wire (30), and frequency converter (69) signal output links to each other with the motor (22) of two-way pump/motor (24) by another holding wire (70).

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