Hydraulic oil deironing device with temperature control system and deironing method thereof

Abstract

The invention provides a hydraulic oil iron removal device with a temperature control system and an iron removal method of the hydraulic oil iron removal device. The hydraulic oil iron removal device comprises an iron remover and the temperature control system. The de-ironing separator comprises a covering structure and a containing structure, and the covering structure and the containing structure are detachably connected to form a closed containing cavity with an openable cover. At least one electromagnet is arranged on the end face, making contact with the containing structure, of the covering structure. The containing structure is provided with an oil inlet part and an oil outlet part which are connected with a hydraulic oil storage container so as to form a hydraulic oil circulation loop; and a temperature sensor is arranged in the iron remover. Magnetic particles in hydraulic oil can be effectively removed, the service life of hydraulic elements is prolonged, and the hydraulic oil is recycled; the electromagnet is used as a part for adsorbing magnetic particles and heating, so that the iron removal efficiency is greatly improved, additional heating elements are avoided, the structure is simple and compact, and the cost is saved.

Description

Technical Field

[0001] The invention relates to the technical field of hydraulic oil iron removal, in particular to a hydraulic oil iron removal device with a temperature control system and an iron removal method thereof. Background Art

[0002] At present, hydraulic devices are used in wind power, aerospace, heavy-duty vehicles and other fields for driving, control and other functions. However, when hydraulic pumps, hydraulic valves and other components are in use, the surface material of the components will fall off due to friction, collision, cavitation and other reasons. These shed materials generally circulate in the system with the hydraulic oil in the form of magnetic particles, and these particles will erode and rub the hydraulic components, causing secondary damage. At present, traditional hydraulic oil iron removers usually rely on permanent magnets to absorb magnetic particles, and the viscosity and fluidity of hydraulic oil will change with temperature. Traditional iron removers cannot actively adjust the oil temperature, resulting in unstable iron removal effect under different working conditions.

[0003] Since traditional iron removers cannot effectively remove magnetic particles, the frequency of replacing hydraulic oil is still high, which not only increases labor and time costs, but also causes a huge waste of resources. Therefore, it is necessary to develop a hydraulic oil impurity removal device that can work effectively under different working conditions to prevent magnetic particles from causing secondary damage to hydraulic components. Summary of the invention

[0004] The purpose of the present invention is to provide a hydraulic oil iron removal device with a temperature control system and an iron removal method thereof, which can effectively remove magnetic particles in the hydraulic oil, extend the service life of the hydraulic components, and realize the reuse of the hydraulic oil.

[0005] To achieve the above object, the technical solution of the present invention is: a hydraulic oil iron removal device with a temperature control system, comprising an iron remover and a temperature control system;

[0006] The iron remover comprises a covering structure and a containing structure, which are detachably connected to each other to form a closed cavity with an openable cover; the end surface of the covering structure in contact with the containing structure is provided with at least one electromagnet; the containing structure has an oil inlet part and an oil outlet part connected to a hydraulic oil storage container to form a hydraulic oil circulation loop; a temperature sensor is provided in the iron remover;

[0007] The temperature control system includes a power module and an electric control module; the power module has a high voltage source and a low voltage source, the electric control module is respectively connected to the power module, the electromagnet and the temperature sensor, and the electric control module controls the electromagnet to connect to the high voltage source or the low voltage source according to the temperature collected by the temperature sensor.

[0008] Preferably, the oil outlet portion includes an oil outlet pipe and a radiator; the oil outlet pipe is connected to the hydraulic oil storage container and the containing structure, and the radiator is arranged on the oil outlet pipe to cool the hydraulic oil in the oil outlet pipe;

[0009] The radiator is connected to an electric control module, and the electric control module controls the opening and closing of the radiator fan according to the temperature collected by the temperature sensor;

[0010] The temperature control system also includes a PID control module, which is connected to the temperature sensor, the radiator and the electronic control module respectively, and the PID control module cooperates with the electronic control module to control the speed of the radiator fan according to the temperature collected by the temperature sensor to stabilize the hydraulic oil temperature.

[0011] Preferably, the oil inlet part includes an oil inlet pipe, a hydraulic pump, and a one-way valve; the oil inlet pipe connects the hydraulic oil storage container and the containing structure, and the hydraulic pump and the one-way valve are arranged on the oil inlet pipe to transport the hydraulic oil in the hydraulic oil storage container to the containing structure in one direction.

[0012] Preferably, the oil inlet part further includes a relief valve, which is arranged on the oil inlet pipe and is used to open the valve port of the relief valve to unload when the pressure of the hydraulic oil exceeds the set value of the relief valve.

[0013] Preferably, a plurality of permanent magnets are fixed to the end surface of the iron remover covering structure in contact with the accommodating structure.

[0014] Preferably, the permanent magnets and the electromagnets are arranged alternately.

[0015] A method for removing iron from a hydraulic oil iron removal device with a temperature control system, specifically comprising the following steps:

[0016] S1, controlling the hydraulic oil to circulate in a circulation loop including an iron remover, a hydraulic oil storage container, an oil inlet part and an oil outlet part;

[0017] The electromagnet is connected to the power module through the electronic control module, and the hydraulic oil in the iron remover is heated by the electromagnet, and the magnetic particles in the hydraulic oil are absorbed by the electromagnet / electromagnet and permanent magnet;

[0018] The temperature sensor collects the hydraulic oil temperature T4 in the iron remover in real time and sends the temperature T4 to the electronic control module and the PID control module;

[0019] S2, the electric control module and the PID control module control the radiator and switch the power module connected to the electromagnet according to the preset optimal working temperature range and the hydraulic oil temperature T4, so that the hydraulic oil inside the iron remover is in the optimal working temperature range when the iron remover is working;

[0020] S3. When the electromagnet / electromagnet and permanent magnet are full of magnetic particles, the hydraulic oil is controlled to stop circulating, the electromagnet is connected to a low voltage source, and the radiator works to cool the hydraulic oil until its temperature drops to a temperature convenient for subsequent operations. The covering structure is then removed and the adsorbed magnetic particles are removed, completing the hydraulic oil impurity removal work.

[0021] Preferably, S2 is specifically:

[0022] The lowest working temperature T1, the highest working temperature T2 and the optimum working temperature T3 in the optimal working temperature range are recorded, and T1 <T3<T2;

[0023] When the temperature T4 obtained by the PID control module and the electronic control module is greater than T2, the electronic control module connects the electromagnet to a low voltage source to put the electromagnet in a low voltage state, and starts the radiator to reduce the oil temperature T4 to T3, and then connects the electromagnet to a high voltage source to put the electromagnet in a high voltage state. At the same time, the PID control module controls the operating power of the radiator to keep the oil temperature within the optimal working temperature range;

[0024] When the temperature T4 obtained by the PID control module and the electronic control module is less than T1, the electronic control module connects the electromagnet to a high voltage source to put the electromagnet in a high voltage state, and the electronic control module stops the radiator from working, causing the oil temperature to rise. When the oil temperature reaches T3, the electronic control module controls the radiator to start working, and at the same time the PID control module controls the operating power of the radiator to keep the oil temperature within the optimal working temperature range.

[0025] When the temperature T4 obtained by the PID control module and the electronic control module is greater than T1 and less than T2, the electronic control module connects the electromagnet to the high voltage source to put the electromagnet in a high voltage state. The electronic control module controls the radiator to start working. At the same time, the PID control module controls the operating power of the radiator to keep the oil temperature within the optimal working temperature range.

[0026] Preferably, the PID control module obtains an input signal through a temperature sensor and outputs a digital control signal to the radiator fan. The specific expression is as follows:

[0027]

[0028] Where: k is the time; e is the temperature error between the input and feedback obtained by the temperature sensor; K p is the proportionality coefficient; K i is the integral coefficient; K d is the differential coefficient;

[0029] The radiator fan speed is adjusted by the PID control module, which is specifically expressed as:

[0030] n=tanh(u(k))·n max

[0031] In the above formula: n is the fan speed, tanh is the hyperbolic tangent function, u(k) is the output signal of the PID control module, n max The maximum fan speed.

[0032] Preferably, step S3 is implemented by a stop button provided in the electronic control module for controlling the opening and closing of the iron removal device. When the stop button is pressed, the hydraulic pump stops working and supplying oil, and the electronic control module connects the electromagnet to a low-voltage source to put the electromagnet in a low-voltage state. At the same time, the electronic control module controls the radiator to operate at maximum power to lower the oil temperature, so that the covering structure and the containing structure of the iron remover can be separated subsequently and the adsorbed magnetic particles can be removed.

[0033] Compared with the prior art, the present invention has the following beneficial effects:

[0034] (1) The present invention not only improves the iron removal efficiency by integrating a temperature control system and an optimized electromagnet design, but also ensures that the iron removal process is carried out under optimal temperature conditions by precisely controlling the temperature of the hydraulic oil. This temperature control capability significantly improves the iron removal efficiency while avoiding the reduction in iron removal efficiency caused by temperature fluctuations.

[0035] (2) The present invention achieves efficient iron removal under different working conditions by combining different magnets and different power sources. At the same time, the scalability of the system facilitates future technology upgrades and changes in working conditions, ensuring long-term maintenance and operating efficiency.

[0036] (3) The present invention dynamically adjusts the speed of the cooling fan based on actual working conditions, thereby achieving accurate temperature matching, improving iron removal efficiency and helping to extend the service life of hydraulic oil and equipment.

[0037] (4) The iron remover structure design of the present invention adopts a bolt fixing method to simplify the disassembly and assembly process of the covering structure. At the same time, the alternating arrangement of permanent magnets and electromagnets improves the adsorption efficiency of magnetic particles and helps to evenly distribute the oil temperature, ensuring the uniformity and efficiency of the iron removal process.

[0038] The present invention can effectively remove magnetic particles in hydraulic oil, extend the service life of hydraulic components, and realize the reuse of hydraulic oil; using electromagnets as adsorbing magnetic particles and heating components greatly improves the iron removal efficiency while avoiding the use of additional heating components, has a simple and compact structure, and saves costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] Figure 1 It is a schematic diagram of the iron removal device;

[0040] Figure 2It is a structural schematic diagram of the iron remover of the present invention;

[0041] Figure 3 This is the internal structure diagram of the iron remover;

[0042] Figure 4 It is a schematic diagram of the covering structure of the iron remover;

[0043] Figure 5 This is the connection diagram of the temperature control system of the iron remover. DETAILED DESCRIPTION

[0044] The technical solution of the present invention is described in detail below in conjunction with the accompanying drawings.

[0045] like Figures 1 to 5 The present invention provides a hydraulic oil iron removal device with a temperature control system, including an iron remover 5 and a temperature control system, wherein the iron remover 5 includes a containing structure 52 with a detachable covering structure 51, at least one electromagnet 53 is fixed to the bottom of the covering structure 51, and the Joule heat generated by the electromagnet 53 when it is energized can heat the hydraulic oil to reduce its viscosity, thereby reducing the relative movement resistance of the hydraulic oil to the magnetic particles, making them easier to be adsorbed; the containing structure 52 has an oil inlet 54 for the hydraulic oil to enter the containing structure 52, and an oil outlet 55 for the hydraulic oil to flow out, the oil inlet 54 is connected to the oil tank 1 through the oil inlet pipe 13, and the oil outlet 55 is connected to the oil tank 1 through the oil outlet pipe 14, so that the hydraulic oil flows into the iron remover 5 through the oil inlet pipe 13, and then flows back to the oil tank 1 through the oil outlet pipe 14, in a circulating state; a temperature sensor 7 is installed in the containing structure 52 for reading the temperature of the hydraulic oil in the containing structure 52.

[0046] The contaminated hydraulic oil is passed into the iron remover 5, and the electromagnet 53 and the permanent magnet 56 inside the iron remover 5 will absorb the magnetic particles in the hydraulic oil. The hydraulic oil with the magnetic particles removed can be put into use again.

[0047] The temperature control system includes a power module 9, an electric control module 12 and a PID control module 11; the power module 9 has a high voltage source 8 and a low voltage source 10, the electric control module 12 is respectively connected to the power module 9, the electromagnet 53 and the temperature sensor 7, and the PID control module 11 is connected to the electric control module 12.

[0048] The oil inlet pipe 13 is installed with a hydraulic pump 2 and a one-way valve 3 . The hydraulic pump 2 can deliver the hydraulic oil, and the one-way valve 3 can prevent the hydraulic oil from flowing back.

[0049] A radiator 6 is installed on the outlet pipe 14, and the radiator 6 is connected to the electronic control module 12 and the PID control module 11. The electronic control module 12 controls the maximum power working state and shutdown of the radiator 6 fan, while the PID control module 11 controls the rotation speed of the radiator 6 fan to stabilize the hydraulic oil temperature.

[0050] A plurality of permanent magnets 56 are also fixed to the bottom of the covering structure 51. Through the permanent magnets 56, the adsorption of magnetic particles can be cooperated with the electromagnet 53 to improve the adsorption effect. The permanent magnets 56 and the electromagnets 53 are arranged alternately, which can disperse the electromagnets, make the oil temperature rise more evenly, and prevent the phenomenon of local overheating of the oil.

[0051] When the electronic control module 12 connects the electromagnet 53 to the high-voltage source 8, the electromagnet 53 has the functions of heating and high magnetism at this time; the electromagnet 53 can heat the hydraulic oil, reduce its viscosity, so that the relative movement resistance of the magnetic particles by the hydraulic oil is reduced, and the magnetic particles can be better adsorbed under the action of the high-magnetic electromagnet; when the electronic control module 12 connects the electromagnet 53 to the low-voltage power supply 10, the electromagnet 53 has the functions of low heating and low magnetism at this time, and the permanent magnet 56 will be the main component for adsorbing magnetic particles.

[0052] When the permanent magnet 56 and the electromagnet 53 are full of magnetic particles, the electromagnet 53 is connected to the low-voltage power supply 10, and the radiator 6 works to cool the hydraulic oil. When its temperature drops to the normal temperature, then the covering structure 51 is taken out, and the adsorbed magnetic particles are removed, that is, the impurity removal work of the hydraulic oil is completed.

[0053] The present invention also provides a method for removing iron from a hydraulic oil iron removal device with a temperature control system, and the method is as follows:

[0054] In order to ensure that the hydraulic oil inside the iron remover 5 is within the optimal working temperature range during operation, the PID control module 11 is used as the main control unit to control the rotation speed of the radiator 6 fan.

[0055] In the PID control module 11 of the iron removal device, the lowest working temperature T1, the highest working temperature T2, and the optimal working temperature T3 within the optimal working temperature range are set, where T1 < T3 < T2, and T4 is the oil temperature of the hydraulic oil entering the iron remover 5 obtained by the temperature sensor 7.

[0056] During the operation of this embodiment, the hydraulic pump 2 and the one-way valve 3 are started, and the hydraulic oil in the fuel tank 1 flows into the iron remover 5 through the inlet pipe 13, and then flows back to the fuel tank 1 through the outlet pipe 14, showing a circulating state.

[0057] When the temperature T4 obtained by the PID control module 11 and the electric control module 12 is greater than T2, the electric control module 12 connects the electromagnet 53 to the low voltage source 10, so that the electromagnet 53 is in a low voltage state. In this process, the electromagnet 53 has low heat generation and low magnetism. In this process, the permanent magnet 56 is the main component for adsorbing magnetic particles. The electric control module 12 starts the radiator 6 to reduce the oil temperature to T3, and then the radiator 6 is controlled by the PID control module 11. At the same time, the electric control module 12 connects the electromagnet 53 to the high voltage source 8, so that the electromagnet 53 is in a high voltage state.

[0058] When the temperature T4 obtained by the PID control module 11 and the electric control module 12 is less than T1, the electric control module 12 connects the electromagnet 53 to the high voltage source 8, so that the electromagnet 53 is in a high voltage state, and the electric control module 12 stops the radiator 6 from working, and the oil temperature rises. In this process, the electromagnet 53 has a heating and high magnetic function; when the oil temperature reaches T3, the PID control module 11 controls the radiator 6 to start working.

[0059] When the temperature T4 obtained by the PID control module 11 and the electronic control module 12 is greater than T1 and less than T2, the electronic control module 12 connects the electromagnet 53 to the high voltage source 8, so that the electromagnet 53 is in a high voltage state, and the electronic control module 12 makes the radiator 6 work, and at the same time the PID control module 11 controls the radiator 6 to start working.

[0060] In the temperature range controlled by the PID control module, the higher the oil temperature, the faster the radiator fan speed. The PID control module 11 obtains the input signal through the temperature sensor 7, and the formula of the digital control signal output to the radiator 6 fan is as follows:

[0061]

[0062] In the above formula: k is the time; e is the temperature error between the input and feedback obtained by the temperature sensor; K p is the proportionality coefficient; K i is the integral coefficient; K d is the differential coefficient.

[0063] The radiator fan speed is adjusted by the PID control module, which is specifically expressed as:

[0064] n=tanh(u(k))·n max

[0065] In the above formula: n is the fan speed, tanh is the hyperbolic tangent function, u(k) is the output signal of the PID control module, n max The maximum fan speed.

[0066] The electronic control module 12 is provided with a stop button for controlling the opening and closing of the iron removal device. When the stop button is pressed, the hydraulic pump 2 stops working and the oil is supplied. At the same time, the electronic control module 12 connects the electromagnet to the low-voltage source 10, so that the electromagnet 53 is in a low-voltage state, and the oil is cooled through the radiator 6.

[0067] The situations where you need to press the stop button are as follows:

[0068] (1) When the permanent magnet 56 and the electromagnet 53 of the iron remover 5 are full of magnetic particles and need to be cleaned, press the stop button to prevent affecting the iron removal performance;

[0069] (2) Press the stop button when maintenance is required or a malfunction occurs.

[0070] In addition to the above-mentioned stop button method to trigger the opening and closing of the iron removal device, induction triggering can also be performed by setting a flow sensor in the pipeline or a liquid level meter in the cylinder. In actual work, in addition to the possible shutdown described in the present invention, passive triggering can also be included.

[0071] In one embodiment of the present invention, a relief valve 4 is also installed on the oil inlet pipe 13. When the pressure of the hydraulic oil exceeds the set value of the relief valve 4, the valve port of the relief valve 4 will open to unload the load, thereby preventing damage to the equipment due to excessive pressure.

[0072] In one embodiment of the present invention, the covering structure 51 is fixed to the containing structure 52 by bolts, so that the covering structure 51 can be easily assembled and disassembled.

[0073] The above description is only a preferred embodiment of the present invention and should not be construed as limiting the present application. All equivalent changes and modifications made within the scope of the patent application of the present invention should fall within the scope of the present invention.

Claims

1. A hydraulic oil iron removal device with a temperature control system, characterized in that: Including iron remover and temperature control system; The iron remover comprises a covering structure and a containing structure, which are detachably connected to each other to form a closed cavity with an openable cover; the end surface of the covering structure in contact with the containing structure is provided with at least one electromagnet; the containing structure has an oil inlet part and an oil outlet part connected to a hydraulic oil storage container to form a hydraulic oil circulation loop; a temperature sensor is provided in the iron remover; The temperature control system includes a power module and an electric control module; the power module has a high voltage source and a low voltage source, the electric control module is respectively connected to the power module, the electromagnet and the temperature sensor, and the electric control module controls the electromagnet to connect to the high voltage source or the low voltage source according to the temperature collected by the temperature sensor.

2. The hydraulic oil iron removal device with a temperature control system according to claim 1, characterized in that: The oil outlet part includes an oil outlet pipe and a radiator; the oil outlet pipe is connected to the hydraulic oil storage container and the containing structure, and the radiator is arranged on the oil outlet pipe to cool the hydraulic oil in the oil outlet pipe; The radiator is connected to an electric control module, and the electric control module controls the opening and closing of the radiator fan according to the temperature collected by the temperature sensor; The temperature control system also includes a PID control module, which is connected to the temperature sensor, the radiator and the electronic control module respectively, and the PID control module cooperates with the electronic control module to control the speed of the radiator fan according to the temperature collected by the temperature sensor to stabilize the hydraulic oil temperature.

3. The hydraulic oil iron removal device with a temperature control system according to claim 2, characterized in that: The oil inlet part includes an oil inlet pipe, a hydraulic pump, and a one-way valve; the oil inlet pipe connects the hydraulic oil storage container and the containing structure, and the hydraulic pump and the one-way valve are arranged on the oil inlet pipe to transport the hydraulic oil in the hydraulic oil storage container to the containing structure in one direction.

4. The hydraulic oil iron removal device with a temperature control system according to claim 2, characterized in that: The oil inlet part also includes a relief valve, which is arranged on the oil inlet pipe and is used to open the valve port of the relief valve to unload when the pressure of the hydraulic oil exceeds the set value of the relief valve.

5. The hydraulic oil iron removal device with a temperature control system according to claim 2, characterized in that: A plurality of permanent magnets are also fixed to the end surface of the iron remover covering structure that contacts the containing structure.

6. The hydraulic oil iron removal device with a temperature control system according to claim 5, characterized in that: The permanent magnets and the electromagnets are arranged alternately.

7. A method for removing iron using a hydraulic oil iron removal device with a temperature control system as claimed in any one of claims 2 to 6, characterized in that: The specific steps include: S1, controlling the hydraulic oil to circulate in a circulation loop including an iron remover, a hydraulic oil storage container, an oil inlet part and an oil outlet part; The electromagnet is connected to the power module through the electronic control module, and the hydraulic oil in the iron remover is heated by the electromagnet, and the magnetic particles in the hydraulic oil are absorbed by the electromagnet / electromagnet and permanent magnet; The temperature sensor collects the hydraulic oil temperature T4 in the iron remover in real time and sends the temperature T4 to the electronic control module and the PID control module; S2, the electric control module and the PID control module control the radiator and switch the power module connected to the electromagnet according to the preset optimal working temperature range and the hydraulic oil temperature T4, so that the hydraulic oil inside the iron remover is in the optimal working temperature range when the iron remover is working; S3. When the electromagnet / electromagnet and permanent magnet are full of magnetic particles, the hydraulic oil is controlled to stop circulating, the electromagnet is connected to a low voltage source, and the radiator works to cool the hydraulic oil until its temperature drops to a temperature convenient for subsequent operations. The covering structure is then removed and the adsorbed magnetic particles are removed, completing the hydraulic oil impurity removal work.

8. The iron removal method of a hydraulic oil iron removal device with a temperature control system according to claim 7, characterized in that: The S2 is specifically: The lowest working temperature T1, the highest working temperature T2 and the optimum working temperature T3 in the optimal working temperature range are recorded, and T1 <T3<T2, When the temperature T4 obtained by the PID control module and the electronic control module is greater than T2, the electronic control module connects the electromagnet to a low voltage source to put the electromagnet in a low voltage state, and starts the radiator to reduce the oil temperature T4 to T3, and then connects the electromagnet to a high voltage source to put the electromagnet in a high voltage state. At the same time, the PID control module controls the operating power of the radiator to keep the oil temperature within the optimal working temperature range; When the temperature T4 obtained by the PID control module and the electronic control module is less than T1, the electronic control module connects the electromagnet to the high voltage source, so that the electromagnet is in a high voltage state, and the electronic control module stops the radiator from working, and the oil temperature rises; when the oil temperature reaches T3, the electronic control module controls the radiator to start working, and the PID control module controls the operating power of the radiator, so that the oil temperature is kept within the optimal working temperature range; When the temperature T4 obtained by the PID control module and the electronic control module is greater than T1 and less than T2, the electronic control module connects the electromagnet to the high voltage source to put the electromagnet in a high voltage state. The electronic control module controls the radiator to start working. At the same time, the PID control module controls the operating power of the radiator to keep the oil temperature within the optimal working temperature range.

9. The iron removal method of a hydraulic oil iron removal device with a temperature control system according to claim 8, characterized in that: The PID control module obtains an input signal through a temperature sensor and outputs a digital control signal to the radiator fan. The specific expression is as follows: Where: k is the time; e is the temperature error between the input and feedback obtained by the temperature sensor; K p is the proportionality coefficient; K i is the integral coefficient; K d is the differential coefficient; The radiator fan speed is adjusted by the PID control module, which is specifically expressed as: n=tanh(u(k))·n max In the above formula: n is the fan speed, tanh is the hyperbolic tangent function, u(k) is the output signal of the PID control module, n max The maximum fan speed.

10. A method for removing iron using a hydraulic oil iron removal device with a temperature control system according to any one of claim 7, characterized in that: The step S3 is implemented by setting a stop button in the electronic control module for controlling the opening and closing of the iron removal device. When the stop button is pressed, the hydraulic pump stops working and supplying oil, and the electronic control module connects the electromagnet to a low-voltage source to put the electromagnet in a low-voltage state. At the same time, the electronic control module controls the radiator to operate at maximum power to reduce the oil temperature, so that the covering structure and the containing structure of the iron remover can be separated and the adsorbed magnetic particles can be removed.

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