Variable frequency hydraulic closed drive system and control method for screw conveyor of shield machine

Abstract

The present invention discloses a variable frequency hydraulic closed drive system and control method for a screw conveyor for a shield machine, comprising a hydraulic motor connected to the screw conveyor, the hydraulic motor being connected to a bidirectional rotary quantitative pump, the bidirectional rotary quantitative pump being driven by a variable frequency motor, the variable frequency motor being connected to a main control room via a variable frequency controller, the inlet and outlet of the hydraulic motor being respectively connected to the inlet and outlet of the bidirectional rotary quantitative pump via a hydraulic pipeline, a flushing valve group and an oil replenishing valve group and a first pressure sensor connected to the main control room being arranged on the hydraulic pipeline, and the oil replenishing valve group being connected to the main control room. The present invention not only effectively guarantees the reliability, safety, and energy-saving economy of the screw conveyor of the shield machine during the construction process, but also effectively improves the efficiency of the shield machine during the construction process, effectively reduces the construction cost of the enterprise, and effectively improves the economic benefits of the enterprise.

Description

Technical Field

[0001] The invention relates to the technical field of drive systems for screw conveyors, and in particular to a variable frequency hydraulic closed drive system and a control method for a screw conveyor for a shield machine. Background Art

[0002] The screw conveyor is a very important component of the earth pressure balance shield machine. Its main function is to transport the slag cut by the shield machine cutter and dropped into the soil bin to the belt conveyor through the screw conveyor. The working efficiency and reliability of the screw conveyor directly determine the progress of the construction. The screw conveyor drive is a large load drive with large driving power and large energy loss. In the past, the screw conveyor used a three-phase asynchronous fixed frequency motor to drive the closed variable pump, and then the closed variable pump drove the motor to rotate to drive the screw conveyor to rotate. The system flow was mainly controlled by adjusting the swash plate angle of the pump to control the speed of the motor-driven screw conveyor. The closed variable pump has a complex structure, a high probability of system failure, and the variable mechanism of the closed variable pump has relatively high requirements for system cleanliness. Therefore, the driving method of using a three-phase asynchronous fixed frequency motor to drive the closed variable pump has a high failure rate. Summary of the invention

[0003] In view of the deficiencies in the above-mentioned background technology, the present invention proposes a variable frequency hydraulic closed drive system and control method for a screw conveyor for a shield machine, which solves the technical problem that the existing screw conveyor uses a three-phase asynchronous fixed frequency motor to drive a closed variable pump with a high failure rate.

[0004] The technical solution of the present invention is implemented as follows: a variable frequency hydraulic closed drive system for a screw conveyor for a shield machine, including a hydraulic motor connected to the screw conveyor, the hydraulic motor is connected to a bidirectional rotary quantitative pump, the bidirectional rotary quantitative pump is driven by a variable frequency motor, the variable frequency motor is connected to the main control room through a frequency conversion controller, the inlet and outlet of the hydraulic motor are respectively connected to the inlet and outlet of the bidirectional rotary quantitative pump through a hydraulic pipeline, a flushing valve group and an oil replenishing valve group and a first pressure sensor connected to the main control room are arranged on the hydraulic pipeline, and the oil replenishing valve group is connected to the main control room. The main control room can control the operating state of the variable frequency motor as needed, and then can control the pumping efficiency of the bidirectional rotary quantitative pump, thereby adjusting the rotation speed of the hydraulic motor. Compared with the traditional variable pump, the bidirectional rotary quantitative pump not only has a simple system, low cleanliness requirements, and good stability, but also the variable frequency drive can achieve stepless speed change, which is more energy-saving and efficient.

[0005] Furthermore, the flushing valve group includes a hydraulically controlled reversing valve connected between two hydraulic pipelines, two oil inlet control ports of the hydraulically controlled reversing valve are respectively connected to the two hydraulic pipelines, and the oil outlet of the hydraulically controlled one-way valve is connected to a cooling oil tank. Through the flushing valve group, a part of the high-temperature hydraulic oil in the hydraulic pipeline can be discharged, thereby taking out the heat generated in the closed circulation system. The setting of the hydraulically controlled reversing valve can realize the automatic flushing function, automatically discharge part of the high-temperature hydraulic oil on the side with lower pressure in the hydraulic pipeline, and the control is simpler.

[0006] Furthermore, a back pressure valve is provided between the cooling oil tank and the oil outlet of the hydraulically controlled reversing valve, and the flushing flow rate can be accurately controlled by adjusting the back pressure valve.

[0007] Furthermore, a pressure shuttle valve is provided between the two hydraulic pipelines, and the first pressure sensor is connected to the hydraulic pipeline through the pressure shuttle valve. The main control room can adjust the flushing flow of the back pressure valve according to the data detected by the first pressure sensor, and the setting of the pressure shuttle valve can ensure that the pressure detected by the first pressure sensor is stable and is a pressure value on the higher pressure side.

[0008] Furthermore, a safety valve is provided between the oil replenishment valve group and the hydraulic pipeline, the safety valve includes an oil replenishment check valve and a safety overflow valve connected in parallel, the oil inlet of the safety valve is connected to the oil replenishment overflow valve, and the oil replenishment overflow valve is connected to the overflow oil tank. The setting of the safety valve further ensures the stability of the hydraulic oil pressure in the hydraulic pipeline and fully ensures the safety of the hydraulic pipeline; the setting of the oil replenishment overflow valve further ensures the safety of the system.

[0009] Furthermore, the safety valve is provided with two, the oil inlets of the two safety valves are connected in parallel with the oil replenishment valve group, and the oil outlets of the two safety valves are connected to two hydraulic pipelines respectively. The two safety valves are provided and connected to two hydraulic pipelines respectively, which fully guarantees the oil replenishment efficiency and can ensure that the pressure on the low-pressure side is replenished in time during flushing. In addition, when the pressure of the hydraulic pipeline on one side reaches the setting of the safety valve, the safety overflow valve connected to this side opens the overflow, and then enters the hydraulic pipeline on the low-pressure side through the oil replenishment one-way valve on the other side. Therefore, the safety valve always overflows the oil on the high-pressure side back to the low-pressure side.

[0010] Furthermore, a second pressure sensor is provided between the oil replenishment relief valve and the safety valve, and the second pressure sensor is connected to the main control room. The main control room can monitor the oil supply pressure of the oil replenishment valve group in real time, compare it with the pressure monitored by the first pressure sensor, and then control the oil replenishment valve group to provide an appropriate amount of hydraulic oil.

[0011] A control method for a variable frequency hydraulic closed drive system of a screw conveyor for a shield machine, wherein a main control room controls a variable frequency controller to drive a variable frequency motor to rotate according to the speed requirement of the screw conveyor, and the variable frequency motor controls a bidirectional rotary quantitative pump to supply oil to a hydraulic motor, and then the hydraulic motor drives the screw conveyor to rotate.

[0012] During the circulating oil supply process of the bidirectional rotary metering pump, the oil inlet control port on one side of the hydraulic reversing valve is pushed for reversal by the high-pressure oil in the hydraulic pipeline on the same side, and the oil inlet control port on the other side is connected to another hydraulic pipeline, and the high-temperature hydraulic oil in the hydraulic pipeline flows into the cooling oil tank through the back pressure valve.

[0013] When the cooling oil tank recovers high-temperature hydraulic oil, the main control room starts the oil replenishment valve group to synchronously replenish oil to the two hydraulic pipelines based on the pressure detection of the first pressure sensor. The main control room controls the oil replenishment amount of the oil replenishment valve group in real time through the monitoring data of the first pressure sensor and the second pressure sensor.

[0014] The present invention not only effectively ensures the reliability, safety and energy-saving economy of the screw conveyor of the shield machine during the construction process, but also effectively improves the efficiency of the shield machine during the construction process, effectively reduces the construction cost of the enterprise, and effectively improves the economic benefits of the enterprise. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] In order to more clearly illustrate the embodiments of the present invention, the accompanying drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings in the following description are only some embodiments of the present invention. For ordinary technicians in this field, other accompanying drawings can be obtained based on these accompanying drawings without paying any creative work.

[0016] Figure 1 It is a system schematic diagram of the present invention. DETAILED DESCRIPTION

[0017] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0018] Embodiment 1, the variable frequency hydraulic closed drive system of the screw conveyor for shield machine, such as Figure 1As shown, it includes a hydraulic motor 6 connected to a screw conveyor, and the hydraulic motor 6 is connected to a bidirectional rotary metering pump 1, and the bidirectional rotary metering pump 1 is driven by a variable frequency motor 2. The variable frequency motor 2 is connected to the main control room through a variable frequency controller, and the main control room can remotely control the stepless speed change of the variable frequency motor. The inlet and outlet of the hydraulic motor 6 are respectively connected to the inlet and outlet of the bidirectional rotary metering pump 1 through a hydraulic pipeline to form a closed circulation system. The stepless speed change of the variable frequency motor 2 can drive the hydraulic motor 6 to achieve stepless speed change through the bidirectional rotary metering pump 1. Compared with the traditional variable pump, the bidirectional rotary metering pump 1 not only has a simple system, low cleanliness requirements, and good stability, but also the variable frequency drive can achieve stepless speed change, which is more energy-saving and efficient.

[0019] In order to ensure that the heat in the closed circulation system can be easily dissipated, the hydraulic pipeline is provided with a flushing valve group 4, an oil replenishing valve group 5 and a first pressure sensor 13 connected to the main control room, wherein the oil replenishing valve group 5 is connected to the main control room. The main control room can control the operating state of the variable frequency motor 2 as needed, and then control the pumping efficiency of the bidirectional rotary quantitative pump 1, thereby adjusting the rotation speed of the hydraulic motor 6. The main control room can also timely control the oil replenishing valve group 5 to replenish the closed circulation system according to the pressure value detected by the first pressure sensor 13.

[0020] The flushing valve group 4 includes a hydraulically controlled reversing valve 11 connected between two hydraulic pipelines. The two oil inlet control ports of the hydraulically controlled reversing valve 11 are respectively connected to the two hydraulic pipelines, and the oil outlet of the hydraulically controlled one-way valve 11 is connected to the cooling oil tank 14. A part of the high-temperature hydraulic oil in the hydraulic pipeline can be discharged through the flushing valve group 4, thereby taking out the heat generated in the closed circulation system. The setting of the hydraulically controlled reversing valve 11 can realize the automatic flushing function. The high-pressure side in the two hydraulic pipelines can automatically push the hydraulically controlled one-way valve 11 to reverse, thereby realizing the flow of the normally closed hydraulically controlled reversing valve 11, and discharging part of the high-temperature hydraulic oil on the lower pressure side of the hydraulic pipeline to the cooling oil tank 14, which is simple and convenient to control.

[0021] Embodiment 2, a variable frequency hydraulic closed drive system for a screw conveyor for a shield machine, a back pressure valve 12 is provided between the cooling oil tank 14 and the oil outlet of the hydraulically controlled reversing valve 11, and the flushing flow rate can be accurately controlled by adjusting the back pressure valve 12.

[0022] The other structures of this embodiment are the same as those of Embodiment 1.

[0023] Embodiment 3, the variable frequency hydraulic closed drive system of the screw conveyor for the shield machine, a pressure shuttle valve 10 is provided between the two hydraulic pipelines, and the first pressure sensor 13 is connected to the hydraulic pipeline through the pressure shuttle valve 10. The main control room can adjust the flushing flow of the back pressure valve 12 according to the data detected by the first pressure sensor 13, and the setting of the pressure shuttle valve 10 can ensure that the pressure detected by the first pressure sensor 13 is stable and is the pressure value on the higher pressure side.

[0024] The other structures of this embodiment are the same as those of Embodiment 1 or 2.

[0025] Embodiment 4, variable frequency hydraulic closed drive system of screw conveyor for shield machine, a safety valve 7 is arranged between the oil replenishment valve group 5 and the hydraulic pipeline, the safety valve 7 comprises a parallel oil replenishment check valve 9 and a safety overflow valve 3, the oil inlet of the safety valve 7 is connected to an oil replenishment overflow valve 8, and the oil replenishment overflow valve 8 is connected to an overflow oil tank 15. The setting of the safety valve 7 further ensures the stability of the hydraulic oil pressure in the hydraulic pipeline, and also fully ensures the safety of the hydraulic pipeline; the setting of the oil replenishment overflow valve 8 further ensures the safety of the system.

[0026] The other structures of this embodiment are the same as those of Embodiment 1, 2 or 3.

[0027] Embodiment 5, the variable frequency hydraulic closed drive system of the screw conveyor for the shield machine, the safety valve 7 is provided with two, the oil inlets of the two safety valves 7 are connected in parallel with the oil replenishing valve group 5, and the oil outlets of the two safety valves 7 are respectively connected to the two hydraulic pipelines. The two safety valves 7 are provided and respectively connected to the two hydraulic pipelines, which fully guarantees the oil replenishment efficiency and can ensure that the pressure on the low-pressure side is replenished in time during flushing. In addition, when the pressure of the hydraulic pipeline on one side reaches the setting of the safety valve 7, the safety overflow valve 3 connected to this side opens the overflow, and then enters the hydraulic pipeline on the low-pressure side through the oil replenishment check valve 9 on the other side. Therefore, the safety valve 7 always overflows the oil on the high-pressure side back to the low-pressure side.

[0028] The other structures of this embodiment are the same as those of Embodiment 4.

[0029] Embodiment 6, the variable frequency hydraulic closed drive system of the screw conveyor for the shield machine, a second pressure sensor 16 is provided between the oil replenishment relief valve 8 and the safety valve 7, and the second pressure sensor 16 is connected to the main control room. The main control room can monitor the oil supply pressure of the oil replenishment valve group 5 in real time, compare it with the pressure monitored by the first pressure sensor 13, and then control the oil replenishment valve group 5 to provide an appropriate amount of hydraulic oil.

[0030] The other structures of this embodiment may be the same as any one of Embodiments 1-5.

[0031] Embodiment 7, a control method for a variable frequency hydraulic closed drive system of a screw conveyor for a shield machine, wherein the main control room controls the variable frequency controller to drive the variable frequency motor 2 to rotate according to the speed requirement of the screw conveyor, and the variable frequency motor 2 controls the bidirectional rotary metering pump 1 to supply oil to the hydraulic motor 6, and then the hydraulic motor 6 drives the screw conveyor to rotate.

[0032] During the circulating oil supply process of the bidirectional rotary metering pump 1, the oil inlet control port on one side of the hydraulic reversing valve 11 is pushed for reversal by the high-pressure oil in the hydraulic pipeline on the same side, and the oil inlet control port on the other side is connected to another hydraulic pipeline, and the high-temperature hydraulic oil in the hydraulic pipeline flows into the cooling oil tank 14 through the back pressure valve 12.

[0033] When the cooling oil tank 14 recovers the high-temperature hydraulic oil, the main control room starts the oil replenishing valve group 5 to synchronously replenish the two hydraulic pipelines according to the pressure detection of the first pressure sensor 13. The main control room controls the oil replenishing amount of the oil replenishing valve group 5 in real time through the monitoring data of the first pressure sensor 13 and the second pressure sensor 16.

[0034] The structure of this embodiment may be the same as that of the sixth embodiment.

[0035] The details not described in detail in the present invention are all conventional technical means known to those skilled in the art.

[0036] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A variable frequency hydraulic closed drive system for a screw conveyor for a shield machine, comprising a hydraulic motor connected to the screw conveyor, characterized in that: The hydraulic motor is connected to a bidirectional rotary quantitative pump, which is driven by a variable frequency motor, which is connected to the main control room through a variable frequency controller, and the inlet and outlet of the hydraulic motor are respectively connected to the inlet and outlet of the bidirectional rotary quantitative pump through a hydraulic pipeline, and a flushing valve group and an oil replenishing valve group and a first pressure sensor connected to the main control room are arranged on the hydraulic pipeline, and the oil replenishing valve group is connected to the main control room; The flushing valve group includes a hydraulically controlled reversing valve connected between two hydraulic pipelines, two oil inlet control ports of the hydraulically controlled reversing valve are respectively connected to the two hydraulic pipelines, and the oil outlet of the hydraulically controlled reversing valve is connected to the cooling oil tank; the hydraulically controlled reversing valve realizes automatic flushing, and the high-pressure side in the two hydraulic pipelines automatically pushes the hydraulically controlled reversing valve to reverse, thereby realizing the flow of the normally closed hydraulically controlled reversing valve, and discharging part of the high-temperature hydraulic oil on the side with lower pressure in the hydraulic pipeline to the cooling oil tank; A safety valve is provided between the oil replenishment valve group and the hydraulic pipeline. The safety valve includes a parallel oil replenishment check valve and a safety overflow valve. The oil inlet of the safety valve is connected to the oil replenishment overflow valve, and the oil replenishment overflow valve is connected to the overflow oil tank. Two safety valves are provided. The oil inlets of the two safety valves are connected in parallel with the oil replenishment valve group, and the oil outlets of the two safety valves are connected to two hydraulic pipelines respectively. The two safety valves ensure that the pressure on the low-pressure side is replenished in time during flushing. When the pressure of the hydraulic pipeline on one side reaches the setting of the safety valve, the safety overflow valve connected to this side opens the overflow, and then enters the hydraulic pipeline on the low-pressure side through the oil replenishment check valve on the other side. The safety valve always overflows the oil on the high-pressure side back to the low-pressure side. A back pressure valve is arranged between the cooling oil tank and the oil outlet of the hydraulically controlled reversing valve.

2. The variable frequency hydraulic closed drive system for the screw conveyor for the shield machine according to claim 1 is characterized in that: A pressure measuring shuttle valve is arranged between the two hydraulic pipelines, and the first pressure sensor is connected to the hydraulic pipeline through the pressure measuring shuttle valve.

3. The variable frequency hydraulic closed drive system for a screw conveyor for a shield machine according to any one of claims 1 to 2, characterized in that: A second pressure sensor is arranged between the oil replenishment overflow valve and the safety valve, and the second pressure sensor is connected to the main control room.

4. The control method of the variable frequency hydraulic closed drive system of the screw conveyor for the shield machine according to claim 3 is characterized in that: The main control room controls the frequency conversion controller to drive the frequency conversion motor to rotate according to the speed requirements of the screw conveyor. The frequency conversion motor controls the bidirectional rotary quantitative pump to supply oil to the hydraulic motor, and then the hydraulic motor drives the screw conveyor to rotate.

5. The control method of the variable frequency hydraulic closed drive system of the screw conveyor for the shield machine according to claim 4 is characterized in that: During the circulating oil supply process of the bidirectional rotary metering pump, the oil inlet control port on one side of the hydraulically controlled reversing valve is pushed for reversing by the high-pressure oil in the hydraulic pipeline on the same side, and the oil inlet control port on the other side of the hydraulically controlled reversing valve is connected to another hydraulic pipeline, and the high-temperature hydraulic oil in the hydraulic pipeline flows into the cooling oil tank through the back-pressure valve.

6. The control method of the variable frequency hydraulic closed drive system of the screw conveyor for the shield machine according to claim 5 is characterized in that: When the cooling oil tank recovers high-temperature hydraulic oil, the main control room starts the oil replenishment valve group to synchronously replenish oil to the two hydraulic pipelines based on the pressure detection of the first pressure sensor. The main control room controls the oil replenishment amount of the oil replenishment valve group in real time through the monitoring data of the first pressure sensor and the second pressure sensor.

Images