Electromagnetic unloading loop for driving centrifugal pump of fracturing pump truck

Abstract

The utility model relates to an electromagnetic unloading loop for driving a centrifugal pump of a fracturing pump truck, and belongs to the technical field of hydraulic systems of centrifugal pump driving motors. According to the technical scheme, an oil inlet of a constant displacement pump (4) is communicated with a hydraulic oil tank (1) through an oil suction ball valve (3), an oil outlet of the constant displacement pump (4) is divided into two paths, one path is communicated with an oil inlet of a one-way valve (5), the other path is communicated with a port A of an electromagnetic reversing valve (7), an oil outlet of the one-way valve (5) is divided into two paths, one path is communicated with a centrifugal pump driving hydraulic motor (9), and the other path is communicated with a port B of an electromagnetic reversing valve (7). An oil outlet of a lower cavity of the cartridge valve element is communicated with the oil return block, an oil outlet of an upper cavity of the cartridge valve element is communicated with a port B of the electromagnetic reversing valve, and the port B of the electromagnetic reversing valve is communicated with the oil return block (8). According to the utility model, the no-load rotation dry friction state of the centrifugal pump motor caused by the fact that hydraulic power output by the constant displacement pump just reaches the initial starting pressure of the centrifugal pump motor when the engine is started can be avoided.

Description

Technical Field

[0001] The utility model relates to an electromagnetic unloading circuit for driving a centrifugal pump of a fracturing pump truck, belonging to the technical field of hydraulic systems of centrifugal pump drive motors. Background Art

[0002] The hydraulic system driving the centrifugal pump motor in the fracturing pump truck utilizes an open system design with a design pressure of 21 MPa (3000 psi). The hydraulic system pressure during operation depends on the external load. As long as the system operates normally below the design pressure, it is considered to be operating normally. A vane pump powered by the transmission provides hydraulic power to drive the centrifugal pump motor. A potentiometer mounted on the panel adjusts the opening of the system circuit proportional relief valve, thereby regulating the flow rate entering the centrifugal pump drive motor. The hydraulic system drive pressure is displayed on the panel for easy operator observation.

[0003] The fundamental problem with the current conventional system is that when the engine drives the transmission, because the transmission's power take-off port is directly connected to the vane pump, when the engine starts, the engine drives the transmission to start, and the transmission power take-off drives the vane pump to rotate. The vane pump outputs hydraulic oil power to act on the centrifugal pump drive motor. The oil supply pressure of the centrifugal pump drive motor is limited by the proportional relief valve connected in parallel in the system circuit. When the set pressure of the proportional relief valve is lower than the driving pressure at the beginning of the centrifugal pump drive motor rotation, all the hydraulic oil output by the vane pump passes through the proportional relief valve for low-pressure unloading, and the centrifugal pump drive motor will not rotate. However, due to the minimum spring preload setting of the proportional relief valve, the opening pressure is 0.7Mpa. When a large flow of liquid flows through the main valve, the valve opening pressure is compressed by the spring, and the final minimum relief pressure will exceed 0.7Mpa. This pressure value is just greater than the driving force of the centrifugal pump motor. At this time, the centrifugal pump will idle and there is a risk of dry friction.

[0004] In order to ensure that the centrifugal pump motor is not easily driven when the engine and vane pump are started, the traditional centrifugal pump motor drive circuit adopts a back pressure check valve connected in series in the centrifugal pump motor drive circuit. The presence of the back pressure check valve increases the oil inlet back pressure of the centrifugal pump drive motor. In theory, the driving pressure to drive the centrifugal pump motor to rotate should be greater than the minimum relief pressure set by the proportional relief valve. At this time, the system flow will overflow from the proportional relief valve and return oil. At this time, no fluid will flow through the centrifugal booster pump motor, and the centrifugal pump motor will not idle. However, under actual operating conditions, due to the influence of the spring stiffness of the back pressure check valve structure itself, the back pressure check valve will open slightly even when the pressure is lower than the set value. At this time, some oil in the system flow will act on the hydraulic motor, and the pressure difference on both sides of the motor will drive the hydraulic motor. Utility Model Content

[0005] The purpose of the utility model is to provide an electromagnetic unloading circuit for driving a centrifugal pump of a fracturing pump truck, which can ensure that when the proportional relief valve is adjusted to a low-pressure state, even if the overflow pressure generated by the compression of the proportional relief valve spring increases, the system flow can still be relieved through the electromagnetic unloading cartridge valve group. In this way, almost all the system flow is relieved through the electromagnetic unloading cartridge valve group, and the centrifugal pump drive motor will not be driven, thereby avoiding the risk of dry friction of the centrifugal pump drive motor and solving the above-mentioned problems existing in the background technology.

[0006] The technical solution of the utility model is:

[0007] After derrick hoists and puts in place, stamp fixedly derrick of derrick pin, make hydraulic oil circuit that is set as pin of derrick pin.

[0008] Furthermore, the proportional relief valve includes a proportional relief valve main valve, and a proportional relief valve pilot valve and a pressure gauge are connected in series between the proportional relief valve main valve and the hydraulic oil tank.

[0009] Furthermore, an oil suction ball valve, a temperature control valve and an oil return filter are sequentially provided between the centrifugal pump driving hydraulic motor and the hydraulic oil tank.

[0010] The positive effects of this utility model are as follows: an electromagnetic unloading cartridge valve group is provided between the metering pump and the centrifugal pump drive hydraulic motor. The energized and de-energized states of the electromagnetic reversing valve can be used to control whether the system's main hydraulic oil source is in an unloading or working state, thereby controlling whether the hydraulic oil source on the centrifugal pump drive motor side is connected or disconnected. This prevents the centrifugal pump motor from rotating dryly due to no-load friction caused by the hydraulic power output by the metering pump just reaching the initial starting pressure of the centrifugal pump motor when the engine is started. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] Figure 1 This is a schematic diagram of the internal hydraulic principle of the electromagnetic unloading cartridge valve group according to an embodiment of the present utility model;

[0012] Figure 2This is a hydraulic principle diagram of the electromagnetic unloading circuit of an embodiment of the utility model;

[0013] In the figure: hydraulic oil tank 1, oil suction filter 2, oil suction ball valve 3, metering pump 4, check valve 5, cartridge valve core 6, solenoid reversing valve 7, oil return block 8, centrifugal pump drive hydraulic motor 9, proportional relief valve pilot valve 10, pressure gauge 11, proportional relief valve main valve 12, back pressure check valve 13, temperature control valve 14, bypass check valve 15, hydraulic oil cooler 16, and return oil filter 17. DETAILED DESCRIPTION

[0014] The present invention will be further described below with reference to the accompanying drawings and embodiments:

[0015] Refer to the attached Figure 1 and 2 This embodiment provides an electromagnetic unloading circuit for driving a centrifugal pump on a fracturing pump truck. The hydraulic oil tank 1, the oil suction ball valve 3, the metering pump 4, the check valve 5, and the centrifugal pump driving hydraulic motor 9 are connected in sequence to form a circuit. Proportional relief valves are connected in parallel at both ends of the centrifugal pump driving hydraulic motor 9. An electromagnetic unloading cartridge valve group is set between the metering pump 4 and the centrifugal pump driving hydraulic motor 9. The electromagnetic unloading cartridge valve group includes a cartridge valve core 6 and an electromagnetic reversing valve 7. The oil inlet of the metering pump 4 is connected to the oil suction ball valve. 3 is connected to the hydraulic oil tank 1, the oil outlet of the quantitative pump 4 is divided into two ways, one way is connected to the oil inlet of the one-way valve 5, and the other way is connected to the A port of the electromagnetic reversing valve 7, the oil outlet of the one-way valve 5 is divided into two ways, one way is connected to the centrifugal pump driving hydraulic motor 9, and the other way is connected to the oil inlet of the cartridge valve core 6, the lower cavity oil outlet of the cartridge valve core 6 is connected to the oil return block 8, the upper cavity oil outlet of the cartridge valve core 6 is connected to the B port of the electromagnetic reversing valve 7, and the B port of the electromagnetic reversing valve 7 is connected to the oil return block 8.

[0016] Refer to the attached Figure 1 The hydraulic oil power output by the metering pump 4 is divided into two paths after passing through the one-way valve 5. One path enters the centrifugal pump to drive the hydraulic motor 9, and the other path passes through the plug-in valve core 6 and flows into the return oil block 8 to release pressure or is blocked by the opening of the plug-in valve core 6 to seal and hold pressure. The two working conditions of pressure relief and pressure holding depend on the power-on and power-off status of the electromagnetic reversing valve 7.

[0017] When the solenoid reversing valve 7 loses power, the B port of the solenoid reversing valve 7 is connected to the upper cavity of the cartridge valve core 6, and the liquid flow in the upper cavity of the cartridge valve core 6 flows into the oil return block 8 through the B port of the solenoid reversing valve 7. The pressure in the upper cavity of the cartridge valve core 6 decreases. At this time, the oil output by the metering pump 4 passes through the one-way valve 5, and the valve core of the cartridge valve core 6 is pushed open by the liquid flow behind the one-way valve 5. The valve core of the cartridge valve core 6 opens, and the liquid flows through the oil outlet of the lower cavity of the cartridge valve core 6 and the B port of the solenoid reversing valve 7 and finally flows into the oil return block 8 to realize the unloading of the system circuit.

[0018] When the electromagnetic reversing valve 7 is energized, the oil outlet of the metering pump 4 is connected to the A port of the electromagnetic reversing valve 7, and the oil output by the metering pump 4 enters the upper chamber of the plug-in valve core 6 through the A port of the electromagnetic reversing valve 7. The pressure acts on the valve core of the plug-in valve core 6 to achieve the closed state of the valve core of the plug-in valve core 6. At this time, the oil output by the metering pump 4 will flow into the drive circuit of the centrifugal pump driving the hydraulic motor 9 after passing through the one-way valve 5. At this time, the drive circuit pressure of the centrifugal pump driving the hydraulic motor 9 gradually builds up until the driving pressure is greater than the starting pressure of the centrifugal pump driving motor, and the centrifugal pump is started.

[0019] In this embodiment, the proportional relief valve includes a proportional relief valve main valve 12 , and a proportional relief valve pilot valve 10 and a pressure gauge 11 are connected in series between the proportional relief valve main valve 12 and the hydraulic oil tank 1 .

[0020] Refer to the attached Figure 2 The unloading process of the electromagnetic unloading circuit of the utility model is as follows:

[0021] Turn the oil suction ball valve 3 to the open position. At this time, the metering pump 4 absorbs hydraulic oil from the hydraulic oil tank 1 through the filtering effect of the oil suction filter 2, and then the metering pump 4 outputs the hydraulic oil to the execution components of the system.

[0022] The liquid flow output by the metering pump 4 is divided into two paths after passing through the one-way valve 5. The main oil path enters the driving end of the centrifugal pump-driven hydraulic motor 9. The main oil path is also connected in parallel with a branch path, on which a proportional relief valve main valve 12 is provided. The proportional relief valve main valve 12 is used to adjust the inlet pressure of the main oil path. The proportional relief valve main valve 12 is remotely controlled by the proportional relief valve pilot valve 10, and the overflow pressure reading is displayed by the pressure gauge 11.

[0023] After the main oil circuit passes through the centrifugal pump-driven hydraulic motor 9, it drives the centrifugal pump-driven hydraulic motor 9 to rotate. The system return oil passes through the back-pressure check valve 13. If the opening pressure setting value of the back-pressure check valve 13 is much higher than the setting value of the proportional relief valve main valve 12, the main oil circuit oil of the system will preferentially overflow through the proportional relief valve main valve 12 and return oil. Due to the back pressure of the back-pressure check valve 13, the centrifugal pump-driven hydraulic motor 9 will not rotate. However, due to the internal structure of the back-pressure check valve 13, there may be a moment when the fluid pressure does not reach the pressure setting value of the back-pressure check valve 13, but the back-pressure check valve 13 will open slightly. At this time, the fluid will enter the temperature control valve 14 through the small opening of the back-pressure check valve 13, and finally return to the hydraulic oil tank 1 through the return oil filter 17. The system fluid will then drive the centrifugal pump-driven hydraulic motor 9, causing the centrifugal pump-driven hydraulic motor 9 to idle. The bypass check valve 15 and the hydraulic oil cooler 16 are used to dissipate heat for the entire system. In order to prevent the centrifugal pump-driven hydraulic motor 9 from idling at this time, a plug-in valve core 6 and an electromagnetic reversing valve 7 are connected to the rear end of the one-way valve 5. The valve core structure of the plug-in valve core 6 has a large-diameter flow and unloading capacity. The lower chamber of the plug-in valve core 6 is connected to the oil return block 8, and the upper chamber of the plug-in valve core 6 is connected in series with the electromagnetic reversing valve 7. The power-on and power-off of the electromagnetic reversing valve 7 determines whether the liquid flow of the plug-in valve core 6 is connected to the oil return block 8 or the oil outlet of the metering pump 4.

[0024] The innovation of the present utility model is that a set of electromagnetic unloading cartridge valve groups is set between the metering pump 4 and the centrifugal pump drive hydraulic motor 9. When the electromagnetic reversing valve 7 loses power, it is in a completely unloaded state, and the upper chamber of the cartridge valve core 6 is connected to the hydraulic oil tank. At this time, the liquid flow of the metering pump 4 opens the one-way valve 5, and the liquid flow of the one-way valve 5 opens the valve core of the cartridge valve core 6. The output flow of the metering pump 4 is completely relieved from the cartridge valve core 6, so that the loaded motor will not be driven. When the electromagnetic reversing valve 7 is energized, the valve core of the cartridge valve core 6 is closed, and the output flow of the metering pump 4 flows through the one-way valve 5 to the driving end of the centrifugal pump drive hydraulic motor 9. At this time, the set pressure of the main relief valve is adjusted, and the system circuit pressure will slowly build up.

[0025] In this embodiment: Hydraulic component model and manufacturer:

[0026] Hydraulic oil tank 1 Chiyu Hydraulics, CYYY series;

[0027] Suction filter 2 Liming Hydraulics, TF series;

[0028] Oil suction ball valve 3 Zhongshan Tiewang, KV series;

[0029] Dosing pump 4 Parker, USA, TC series;

[0030] Check valve 5 Huade Hydraulic SA series;

[0031] Cartridge valve core 6 American SUN, RPCC series;

[0032] Solenoid reversing valve 7 American SUN, PR series;

[0033] Oil return block 8 tee H360 series;

[0034] Centrifugal pump drives hydraulic motor 9 Parker, MS series;

[0035] Proportional relief valve pilot valve 10 Atos ATO series;

[0036] Pressure gauge 11 Tektronix P14P series;

[0037] Proportional relief valve main valve 12 Atos ATO series;

[0038] Back pressure check valve 13 Huade Hydraulic SA series;

[0039] Temperature control valve 14 Nanjing Dibo TBCH series;

[0040] Bypass check valve 15 Huade Hydraulic SA series;

[0041] Hydraulic oil cooler 16 Yantai Ice Wheel B1798 series;

[0042] Return oil filter 17 Liming Hydraulics RF series.

Claims

1. An electromagnetic unloading circuit for driving a centrifugal pump of a fracturing pump truck, wherein a hydraulic oil tank (1), an oil suction ball valve (3), a metering pump (4), a one-way valve (5), and a centrifugal pump driving hydraulic motor (9) are sequentially connected to form a circuit, and proportional relief valves are connected in parallel at both ends of the centrifugal pump driving hydraulic motor (9), characterized in that: An electromagnetic unloading cartridge valve group is provided between the metering pump (4) and the centrifugal pump driving hydraulic motor (9), and the electromagnetic unloading cartridge valve group comprises a cartridge valve core (6) and an electromagnetic reversing valve (7). The oil inlet of the metering pump (4) is connected to the hydraulic oil tank (1) through the oil suction ball valve (3). The oil outlet of the metering pump (4) is divided into two paths, one of which is connected to the oil inlet of the one-way valve (5) and the other is connected to the A port of the electromagnetic reversing valve (7). The oil outlet of the one-way valve (5) is divided into two paths, one of which is connected to the centrifugal pump driving hydraulic motor (9) and the other is connected to the oil inlet of the cartridge valve core (6). The lower cavity oil outlet of the cartridge valve core (6) is connected to the oil return block (8), the upper cavity oil outlet of the cartridge valve core (6) is connected to the B port of the electromagnetic reversing valve (7), and the B port of the electromagnetic reversing valve (7) is connected to the oil return block (8).

2. The electromagnetic unloading circuit for driving a centrifugal pump of a fracturing pump truck according to claim 1, characterized in that: The proportional relief valve comprises a proportional relief valve main valve (12), and a proportional relief valve pilot valve (10) and a pressure gauge (11) are connected in series between the proportional relief valve main valve (12) and the hydraulic oil tank (1).

3. The electromagnetic unloading circuit for driving a centrifugal pump of a fracturing pump truck according to claim 2, characterized in that: An oil suction ball valve (3), a temperature control valve (14) and an oil return filter (17) are sequentially provided between the centrifugal pump driving hydraulic motor (9) and the hydraulic oil tank (1).

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