Automatic control unit for aircraft hydraulic cleaning equipment

Abstract

The utility model discloses a specific plane hydraulic cleaning equipment automatic control unit, including control portion, executive portion and sensing portion, control portion includes the control man -machine interface of plane hydraulic cleaning equipment, programmable controller PLC, switch power supply, PLC includes input, output, control portion passes through PLC, receives all from the control man -machine interface of plane hydraulic cleaning equipment's instruction and the input terminal signal of PLC, sends control command to the output of PLC after logic judgement, the output of executive portion is connected in the output of PLC through communication cable, is responsible for according to the control command of control portion, drives the execution element in plane hydraulic cleaning equipment through the conduction of a series of intermediate relay, sensing portion is connected in the input of PLC through communication cable, is responsible for the series sensor signal feedback of plane hydraulic cleaning equipment to PLC, the utility model discloses high efficiency, and can automatic heating and judge whether the temperature of cleaning oil satisfies the cleaning requirement.

Description

Technical Field

[0001] This utility model relates to the field of aircraft hydraulic cleaning equipment and automatic control, specifically an automatic control unit for aircraft hydraulic cleaning equipment. Background Technology

[0002] Over long-term use, impurities and contaminants accumulate in the hydraulic system lines of aircraft, leading to problems such as line blockage, pressure loss, and insufficient flow. This affects the normal operation of the hydraulic system and, in severe cases, can compromise flight safety. Therefore, it is necessary to clean the hydraulic system lines regularly.

[0003] Currently, the main method for cleaning aircraft hydraulic system pipelines is to use mature and widely used mobile hydraulic pipeline cleaning equipment. The cleaning principle is as follows: cleaning oil is pressurized and pumped into the pipeline to be cleaned, flushing away oil, dust, debris, and other impurities from the inner wall of the pipeline. The cleaning purpose is achieved through repeated and prolonged flushing. However, the existing cleaning equipment has the following problems: First, it requires a lot of manual operation, resulting in long flushing times and low efficiency. Second, because it involves flight safety, aircraft hydraulic system pipelines differ from ordinary hydraulic systems, and the cleaning standards are more stringent. Often, the cleaning oil needs to be heated to a certain temperature to meet the cleaning standards. Existing equipment either cannot heat the cleaning oil or relies on manual experience, requiring repeated manual heating, which is prone to insufficient or excessive temperature and cannot meet the cleaning requirements of aircraft hydraulic system pipelines. Summary of the Invention

[0004] To overcome the shortcomings of existing technologies, this utility model provides an automatic control unit for aircraft hydraulic cleaning equipment. Based on a programmable control chip, a human-machine interface, a switching power supply, and a series of sensors and switches, an automatic control system for aircraft hydraulic cleaning equipment is constructed. This system can automatically perform cleaning operations on aircraft hydraulic system pipelines, requiring less manual operation and achieving high efficiency. It can also automatically heat and determine whether the temperature of the cleaning oil meets the cleaning requirements.

[0005] The technical solution of this utility model is:

[0006] The automatic control unit of the aircraft hydraulic cleaning equipment includes a control unit, an execution unit, and a sensing unit;

[0007] The control unit includes a human-machine interface (HMI) for the aircraft hydraulic cleaning equipment, a programmable logic controller (PLC), and a switching power supply (SMPS). The PLC includes input and output terminals. The switching power supply converts 220V AC to 24V DC to power the HMI and the PLC output terminals of the aircraft hydraulic cleaning equipment. The HMI is connected to the PLC via a communication cable and displays the status parameters of the aircraft hydraulic cleaning equipment's automatic control unit, providing an interface for manual input of commands. The control unit receives all commands from the HMI and input signals from the PLC, and after logical judgment, sends control commands to the PLC output terminals.

[0008] The actuator is connected to the output of the programmable logic controller (PLC) in the control unit via a communication cable. It is responsible for driving the actuators in the aircraft hydraulic cleaning equipment by activating a series of intermediate relays according to the control commands from the control unit. The actuator includes a first intermediate relay KA1, a second intermediate relay KA2, a third intermediate relay KA3, a fourth intermediate relay KA4, a fifth intermediate relay KA5, a sixth intermediate relay KA6, a red indicator light, a yellow indicator light, a green indicator light, and an alarm. The actuators in the aircraft hydraulic cleaning equipment include an oil pump motor for pumping cleaning oil, a cooling fan motor, and a heater R1 for heating the cleaning oil.

[0009] The sensing unit is connected to the input terminal of the programmable logic controller (PLC) in the control unit via a communication cable, and is responsible for feeding back a series of sensor signals from the aircraft hydraulic cleaning equipment to the PLC in the control unit. The sensing unit includes an upper limit oil level sensor, a high oil level sensor, a lower limit operating oil level sensor, a first digital pressure sensor, a second digital pressure sensor, a fan thermal relay feedback terminal, an oil pump thermal relay feedback terminal, a first temperature controller, and a second temperature controller.

[0010] Furthermore, the control unit also includes a cabinet and a first circuit breaker QF1, a second circuit breaker QF2, a current transformer, a first contactor KM1, a second contactor KM2, a solid-state relay SSR, a first thermal relay FR1, a second thermal relay FR2, and a fuse FU1 installed inside the cabinet.

[0011] The human-machine interface for controlling the aircraft hydraulic cleaning equipment is located on the cabinet panel. The first and second temperature controllers are also located on the cabinet panel, while the PLC and switching power supply are located inside the cabinet.

[0012] The first circuit breaker QF1 is a 4-pole switch, and the second circuit breaker QF2 is a 1-pole switch. After the cabinet is connected to 380V AC power through the first circuit breaker QF1, it is divided into three main control circuits. The first main control circuit supplies power to heater R1 after being protected by the first circuit breaker QF1, current transformer, solid-state relay SSR, and fuse FU1. The second main control circuit supplies power to oil pump motor after being protected by the first circuit breaker QF1, current transformer, first contactor KM1, and first thermal relay FR1. The third main control circuit supplies power to fan motor after being protected by the first circuit breaker QF1, current transformer, second contactor KM2, and second thermal relay FR2.

[0013] The first intermediate relay KA1 is connected to the first contactor KM1, the second intermediate relay KA2 is connected to the second contactor KM2, and the third intermediate relay KA3 is connected to the solid-state relay SSR to form a secondary control circuit.

[0014] The fourth intermediate relay KA4 is connected to the first solenoid valve, the fifth intermediate relay KA5 is connected to the second solenoid valve, and the sixth intermediate relay KA6 is connected to the proportional valve to form a low-voltage control circuit; the first solenoid valve, the second solenoid valve, and the proportional valve are the actuators in the aircraft hydraulic cleaning equipment.

[0015] The second circuit breaker is connected to one of the live wires of the power supply connected to the first circuit breaker. The second circuit breaker supplies power to the secondary control circuit, PLC, and switching power supply in sequence. The switching power supply has a built-in rectifier circuit to convert 220V AC to 24V DC. The output port of the switching power supply is connected to the control human-machine interface and PLC output of the aircraft hydraulic cleaning equipment to supply power to the components of the control human-machine interface and PLC output of the aircraft hydraulic cleaning equipment.

[0016] Below the human-machine interface on the cabinet panel is an operation panel, which includes an automatic / manual switch button, a start button, a stop button, and a reset button. These buttons are connected to the input terminals of the PLC in the control unit via communication cables. The automatic / manual switch button is used to switch control modes, the start button is used to start automatic operation, the stop button is used for emergency stop, and the reset button is used to unlock the program and return the system to its initial state after the abnormality is resolved.

[0017] Furthermore, the control unit also includes a remote controller, which is connected to the input terminal of the control unit PLC. The remote controller is equipped with the same automatic / manual switching button, start button, stop button, and reset button as the operation panel, and can remotely achieve the same functions as the control panel buttons.

[0018] Furthermore, in the secondary control circuit, the first intermediate relay KA1 is connected to the first contactor KM1 to control the on and off of the power supply path of the oil pump motor; the second intermediate relay KA2 is connected to the second contactor KM2 to control the on and off of the power supply path of the fan motor; and the third intermediate relay KA3 is connected to the solid-state relay SSR to control the on and off of the power supply path of the heater. In the weak current control circuit, the fourth intermediate relay KA4, the fifth intermediate relay KA5, and the sixth intermediate relay KA6 are respectively used to control the on and off of the power supply paths of the first solenoid valve, the second solenoid valve, and the proportional valve in the oil circuit.

[0019] Furthermore, the sensing unit also includes a first flow sensor and a second flow sensor. The PLC of the control unit is equipped with an AD module and a CPU module. The AD module is a digital-to-analog converter. The first flow sensor and the second flow sensor are connected to the AD module on the PLC of the control unit via cables. At the same time, the sampling data of the first flow sensor and the second flow sensor are converted by AD and then connected to the control human-machine interface of the aircraft hydraulic cleaning equipment via a cable through the communication port of the CPU module. The PLC sends the flow data collected by the two flow sensors to the control human-machine interface of the aircraft hydraulic cleaning equipment for real-time display.

[0020] Furthermore, the specific control of the connection between the actuator and the sensor and the aircraft hydraulic cleaning equipment is as follows:

[0021] The aircraft hydraulic cleaning equipment includes an oil tank, an oil outlet circuit, and an oil return circuit; the oil tank contains cleaning oil; the oil outlet circuit is used to lead the cleaning oil in the oil tank to the hydraulic pipeline to be cleaned; the oil return circuit is used to lead the cleaning oil in the hydraulic pipeline to be cleaned back to the oil tank.

[0022] The oil removal circuit starts from the oil tank and is sequentially connected to the inlet filter, inlet shut-off valve, pre-pump filter, first solenoid valve, oil pump, first pressure sensor, two-stage filter, first flow sensor, check valve, second pressure sensor, and inlet oil pipe interface via pipelines; the inlet oil pipe interface is used to connect to the hydraulic pipeline inlet for cleaning.

[0023] The return oil circuit starts from the outlet of the hydraulic pipeline to be cleaned and is connected in sequence to the outlet oil pipe interface, the second flow sensor, the outlet shut-off valve, the cooling fan, the outlet filter, and the oil tank pipeline; the outlet oil pipe interface is used to connect to the outlet of the hydraulic pipeline to be cleaned; a sampling valve is led out between the cooling fan and the outlet filter, which is used to finally detect whether the impurity content in the sample meets the cleaning completion standard by taking a sample from the cleaning oil.

[0024] The oil pump is driven by an oil pump motor and is used to pump oil from the oil tank. The oil pump motor is powered by the second main control circuit and its on / off state is controlled by the PLC through the third intermediate relay KA3 of the actuator. The feedback terminal of the first thermal relay FR1 is connected to the input terminal of the control unit PLC to detect whether the oil pump motor is overloaded and to provide an oil pump motor overload protection signal to the PLC. If the oil pump motor is overloaded, the oil pump stops, the red indicator light flashes, the alarm sounds, and the human-machine interface prompts that the oil pump motor is overloaded.

[0025] The heating tube is located at the bottom of the oil tank, and a heater R1 is arranged in the heating tube. The heater R1 is powered by the first main control circuit and its on / off state is controlled by the PLC through the third intermediate relay KA3 of the actuator.

[0026] An upper limit oil level sensor is located at the oil tank inlet, while a high oil level sensor and a lower limit operating oil level sensor are located inside the oil tank to detect whether the oil level is within the allowable range. A first solenoid valve controls the opening and closing of the oil supply path, controlled by the PLC via the fourth intermediate relay KA4 of the actuator. A first pressure sensor is located at the oil pump outlet to monitor whether the oil pump pressure reaches the set value, thereby determining the pump's operation and shutdown. A first flow sensor transmits the real-time flow rate of the oil supply path to the PLC and the human-machine interface for real-time monitoring. A second pressure sensor is located at the inlet of the hydraulic pipeline to be cleaned to monitor whether the inlet oil pressure meets the cleaning pressure requirements. A second flow sensor transmits the real-time flow rate of the return oil path to the PLC and the human-machine interface for real-time monitoring.

[0027] A branch line is provided between the first pressure sensor and the two-stage filter to connect the oil outlet to the oil return line, and a proportional valve is installed on this branch line; a branch line is provided between the two-stage filter and the first flow sensor to connect the oil outlet to the oil return line, and a second solenoid valve is installed on this branch line; the PLC controls the opening and closing of the power supply path of the proportional valve and the second solenoid valve through the sixth intermediate relay KA6 and the fifth intermediate relay KA5 in the weak current control circuit; the opening and closing of the proportional valve and the second solenoid valve are used to divert and reduce the pressure of the cleaning oil when the pressure at the front end of the two-stage filter in the oil outlet line is too high or the pressure at the inlet of the hydraulic pipeline to be cleaned is too high;

[0028] The cooling fan is driven by a fan motor to cool the cleaning oil. The fan motor is powered by the third main control circuit and its on / off state is controlled by the PLC through the second intermediate relay KA2 of the actuator. The feedback terminal of the second thermal relay FR2 is connected to the input terminal of the control unit PLC to detect whether the fan motor is overloaded and to provide the PLC with a fan motor overload protection signal. If the fan motor is overloaded, the equipment stops, the red indicator light flashes, the alarm sounds, and the human-machine interface prompts that the fan motor is overloaded.

[0029] Thermocouples are installed inside the oil tank to measure the temperature of the cleaning oil. The first temperature controller, based on the cleaning oil temperature, sends a heating signal to the PLC if the oil temperature is lower than the set value. The PLC then activates the coil of the third intermediate relay KA3, which in turn activates the SSR. The SSR conducts the heating circuit, and heater R1 heats the oil. When the temperature reaches the required value, the first temperature controller disconnects the heating request signal to the PLC, which then disconnects the coil of the third intermediate relay KA3, stopping the heating process. This cycle repeats. If the temperature is too high and exceeds the required cleaning temperature, the second temperature controller sends a cooling signal to the PLC. The PLC then activates the coil of the second intermediate relay KA2, which in turn activates the coil of the second contactor KM2. The contactor engages, and the fan starts to cool the oil, ensuring that the oil remains within the required cleaning temperature range during the circulating cleaning process. The PLC sends the oil temperature collected by the thermocouples to the human-machine interface for real-time display.

[0030] Furthermore, when using the aforementioned aircraft hydraulic cleaning equipment's automatic control unit for automated operation, the specific steps are as follows:

[0031] Step 1: Start-up preparation;

[0032] Check that the oil supply and return lines of the aircraft hydraulic cleaning equipment are connected correctly. If correct, power on the equipment and set the cleaning oil temperature and cleaning time on the human-machine interface. By default, the automatic / manual switch button is set to the automatic side, and the equipment enters self-test mode. The PLC checks whether the conditions of each input port meet the normal start-up and operation conditions, including whether the oil tank level is within the allowable range, whether the oil temperature is within the allowable range, and whether the thermal relay is normal. If the conditions are met, the operator presses the start button or the start button on the remote control to proceed to the next step.

[0033] Step 2: Circulating heating cleaning;

[0034] The PLC activates the KA1 coil, which in turn activates the KM1 coil. The KM1 contactor engages, and the oil pump pumps oil. The oil flows from the tank through the inlet filter, inlet shut-off valve, pre-pump filter, first solenoid valve, oil pump, first pressure sensor, two-stage filter, first flow sensor, check valve, second pressure sensor, and inlet oil pipe interface into the hydraulic pipeline to be cleaned. Then, the oil flows from the hydraulic pipeline to be cleaned through the outlet oil pipe interface, second flow sensor, outlet shut-off valve, cooling fan, and outlet filter back to the tank, forming a cycle.

[0035] During the circulation of the cleaning oil in the pipeline, the thermocouple in the oil tank measures the temperature of the cleaning oil in real time. If the temperature of the cleaning oil is lower than the corresponding set value, the first temperature controller outputs a heating signal to the PLC. The PLC activates the KA3 coil, and the normally open contact of KA3 activates the SSR. The SSR conducts the heating circuit, and the heater R1 heats up, raising the temperature of the oil. When the temperature reaches the required value, the first temperature controller disconnects the heating request signal to the PLC, and the PLC disconnects the KA3 coil, stopping the heating. This cycle repeats. When the temperature is too high and exceeds the required cleaning temperature, the second temperature controller outputs a cooling signal to the PLC. The PLC activates the KA2 coil, and the normally open contact of KA2 activates the KM2 coil. The contactor engages, and the fan starts to cool down the oil. In this way, the oil is kept within the required temperature range during the circulating cleaning process.

[0036] Step 3: When the set cleaning time is reached, the alarm will sound. The operator will manually sample the cleaning oil through the sampling valve and check if the impurity content in the sample meets the cleaning end standard. If it does, press the stop button to stop the equipment and the cleaning is complete. If it does not meet the standard, press the start button to start the next round of cleaning.

[0037] Beneficial effects:

[0038] This utility model provides an automatic control unit for aircraft hydraulic cleaning equipment. Based on a programmable control chip, human-machine interface, switching power supply and a series of sensors and switches, an automatic control system for aircraft hydraulic cleaning equipment is constructed. It can automatically realize the cleaning operation of aircraft hydraulic system pipelines, with less manual operation, high efficiency, and can automatically heat and judge whether the temperature of the cleaning oil meets the cleaning requirements. Attached Figure Description

[0039] Figure 1 This is a circuit schematic diagram of an embodiment of the present utility model;

[0040] Figure 2 This is a schematic diagram of the oil circuit in an embodiment of the present invention. Detailed Implementation

[0041] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments:

[0042] like Figures 1 to 2 As shown, an automatic control unit for an aircraft hydraulic cleaning device includes a control unit, an execution unit, and a sensing unit.

[0043] The control unit includes a human-machine interface (HMI) for the aircraft hydraulic cleaning equipment, a programmable logic controller (PLC), and a switching power supply (SMPS). The PLC includes input and output terminals. The switching power supply converts 220V AC to 24V DC to power the HMI and the PLC output terminals of the aircraft hydraulic cleaning equipment. The HMI is connected to the PLC via a communication cable and displays the status parameters of the aircraft hydraulic cleaning equipment's automatic control unit, providing an interface for manual input of commands. The control unit receives all commands from the HMI and input signals from the PLC, and after logical judgment, sends control commands to the PLC output terminals.

[0044] The actuator is connected to the output of the programmable logic controller (PLC) in the control unit via a communication cable. It is responsible for driving the actuators in the aircraft hydraulic cleaning equipment by activating a series of intermediate relays according to the control commands from the control unit. The actuator includes a first intermediate relay KA1 (in this embodiment...). Figure 1 The middle part is "KA1 oil pump"), and the second intermediate relay KA2 (in this embodiment) Figure 1 The middle one is "KA2 fan"), the third intermediate relay KA3 (in this embodiment) Figure 1 The middle one is "KA3SSR"), the fourth intermediate relay KA4 (in this embodiment) Figure 1 In this embodiment, the fifth intermediate relay KA5 is referred to as "KA4 solenoid valve 1". Figure 1 The middle one is "KA5 solenoid valve 2"), the sixth intermediate relay KA6 (in this embodiment) Figure 1 The device includes a "KA6 proportional valve", a red indicator light, a yellow indicator light, a green indicator light, and an alarm; the actuators in the aircraft hydraulic cleaning equipment include the oil pump motor for pumping cleaning oil, the cooling fan motor, and the heater R1 for heating the cleaning oil.

[0045] The sensing unit is connected to the input terminal of the programmable logic controller (PLC) in the control unit via a communication cable, and is responsible for feeding back a series of sensor signals from the aircraft hydraulic cleaning equipment to the PLC in the control unit. The sensing unit includes an upper limit oil level sensor, a high oil level sensor, a lower limit operating oil level sensor, a digital pressure sensor 1, a digital pressure sensor 2, a fan thermal relay feedback terminal, an oil pump thermal relay feedback terminal, a temperature controller 1, and a temperature controller 2.

[0046] In this embodiment, the control unit further includes a cabinet and a first circuit breaker QF1, a second circuit breaker QF2, a current transformer, a first contactor KM1, a second contactor KM2, a solid-state relay SSR, a first thermal relay FR1, a second thermal relay FR2, and a fuse FU1 installed inside the cabinet.

[0047] The human-machine interface for controlling the aircraft hydraulic cleaning equipment is located on the cabinet panel. Temperature controller 1 and temperature controller 2 are also located on the cabinet panel. The PLC and switching power supply are located inside the cabinet.

[0048] The first circuit breaker QF1 is a 4-pole switch, and the second circuit breaker QF2 is a 1-pole switch. After the cabinet is connected to 380V AC power through the first circuit breaker QF1, it is divided into three main control circuits. The first main control circuit supplies power to heater R1 after being protected by the first circuit breaker QF1, current transformer, solid-state relay SSR, and fuse FU1. The second main control circuit supplies power to oil pump motor after being protected by the first circuit breaker QF1, current transformer, first contactor KM1, and first thermal relay FR1. The third main control circuit supplies power to fan motor after being protected by the first circuit breaker QF1, current transformer, second contactor KM2, and second thermal relay FR2.

[0049] The first intermediate relay KA1 is connected to the first contactor KM1, the second intermediate relay KA2 is connected to the second contactor KM2, and the third intermediate relay KA3 is connected to the solid-state relay SSR to form a secondary control circuit.

[0050] The fourth intermediate relay KA4 is connected to solenoid valve 1, the fifth intermediate relay KA5 is connected to solenoid valve 2, and the sixth intermediate relay KA6 is connected to the proportional valve to form a low-voltage control circuit; the solenoid valve 1, solenoid valve 2, and proportional valve are the actuators in the aircraft hydraulic cleaning equipment.

[0051] The second circuit breaker is connected to one of the live wires of the power supply connected to the first circuit breaker. The second circuit breaker supplies power to the secondary control circuit, PLC, and switching power supply in sequence. The switching power supply has a built-in rectifier circuit to convert 220V AC to 24V DC. The output port of the switching power supply is connected to the control human-machine interface and PLC output of the aircraft hydraulic cleaning equipment to supply power to the components of the control human-machine interface and PLC output of the aircraft hydraulic cleaning equipment.

[0052] Below the human-machine interface on the cabinet panel is an operation panel, which includes an automatic / manual switch button, a start button, a stop button, and a reset button. These buttons are connected to the input terminals of the PLC in the control unit via communication cables. The automatic / manual switch button is used to switch control modes, the start button is used to start automatic operation, the stop button is used for emergency stop, and the reset button is used to unlock the program and return the system to its initial state after the abnormality is resolved.

[0053] In this embodiment, the control unit further includes a remote controller, which is connected to the input terminal of the control unit PLC. The remote controller is equipped with the same automatic / manual switching button, start button, stop button, and reset button as the operation panel, and can remotely achieve the same functions as the control panel buttons.

[0054] In this embodiment, in the secondary control circuit, the first intermediate relay KA1 is connected to the first contactor KM1 to control the on and off of the power supply path of the oil pump motor; the second intermediate relay KA2 is connected to the second contactor KM2 to control the on and off of the power supply path of the fan motor; and the third intermediate relay KA3 is connected to the solid-state relay SSR to control the on and off of the power supply path of the heater. In the weak current control circuit, the fourth intermediate relay KA4, the fifth intermediate relay KA5, and the sixth intermediate relay KA6 are respectively used to control the on and off of the power supply paths of the first solenoid valve, the second solenoid valve, and the proportional valve in the oil circuit.

[0055] In this embodiment, the sensing unit further includes flow sensor 1 and flow sensor 2. The PLC of the control unit is equipped with an AD module and a CPU module. The AD module is a digital-to-analog conversion module. Flow sensor 1 and flow sensor 2 are connected to the AD module on the PLC of the control unit through cables. At the same time, the sampling data of flow sensor 1 and flow sensor 2 are converted by AD and connected to the control human-machine interface of the aircraft hydraulic cleaning equipment through the communication port of the CPU module via cables. The PLC sends the flow data collected by the two flow sensors to the control human-machine interface of the aircraft hydraulic cleaning equipment for real-time display.

[0056] In this embodiment, the association control between the actuator and the sensor and the aircraft hydraulic cleaning equipment is specifically as follows:

[0057] The aircraft hydraulic cleaning equipment includes an oil tank, an oil outlet circuit, and an oil return circuit; the oil tank contains cleaning oil; the oil outlet circuit is used to lead the cleaning oil in the oil tank to the hydraulic pipeline to be cleaned; the oil return circuit is used to lead the cleaning oil in the hydraulic pipeline to be cleaned back to the oil tank.

[0058] The oil removal circuit starts from the oil tank and is connected in sequence to the inlet filter, inlet shut-off valve, pre-pump filter, solenoid valve 1, oil pump, digital pressure sensor 1, two-stage filter, flow sensor 1, check valve, digital pressure sensor 2, and inlet oil pipe interface by pipelines; the inlet oil pipe interface is used to connect to the hydraulic pipeline inlet for cleaning.

[0059] The return oil circuit starts from the outlet of the hydraulic pipeline to be cleaned and is connected in sequence to the outlet oil pipe interface, flow sensor 2, outlet shut-off valve, cooling fan, outlet filter, and oil tank pipeline; the outlet oil pipe interface is used to connect to the outlet of the hydraulic pipeline to be cleaned; a sampling valve is led out between the cooling fan and the outlet filter, which is used to finally detect whether the impurity content in the sample meets the cleaning completion standard by taking a sample from the cleaning oil.

[0060] The oil pump is driven by an oil pump motor and is used to pump oil from the oil tank. The oil pump motor is powered by the second main control circuit and its on / off state is controlled by the PLC through the third intermediate relay KA3 of the actuator. The feedback terminal of the first thermal relay FR1 is connected to the input terminal of the control unit PLC to detect whether the oil pump motor is overloaded and to provide an oil pump motor overload protection signal to the PLC. If the oil pump motor is overloaded, the oil pump stops, the red indicator light flashes, the alarm sounds, and the human-machine interface prompts that the oil pump motor is overloaded.

[0061] The heating tube is located at the bottom of the oil tank, and a heater R1 is arranged in the heating tube. The heater R1 is powered by the first main control circuit and its on / off state is controlled by the PLC through the third intermediate relay KA3 of the actuator.

[0062] An upper limit oil level sensor is located at the oil tank inlet, while a high oil level sensor and a lower limit operating oil level sensor are located inside the oil tank to detect whether the oil level is within the allowable range. Solenoid valve 1 controls the opening and closing of the oil supply path, controlled by the PLC via the fourth intermediate relay KA4 of the actuator. Digital pressure sensor 1 is located at the oil pump outlet to monitor whether the oil pump pressure reaches the set value, thereby determining the pump's operation and shutdown. Flow sensor 1 transmits the real-time flow rate of the oil supply path to the PLC and the human-machine interface for real-time monitoring. Digital pressure sensor 2 is located at the inlet of the hydraulic pipeline to be cleaned to monitor whether the inlet oil pressure of the hydraulic pipeline to be cleaned meets the cleaning pressure requirements. Flow sensor 2 also transmits the real-time flow rate of the return oil path to the PLC and the human-machine interface for real-time monitoring.

[0063] A branch line is provided between the digital pressure sensor 1 and the two-stage filter to connect the oil outlet to the oil return line, and a proportional valve is provided on this branch line; a branch line is provided between the two-stage filter and the flow sensor 1 to connect the oil outlet to the oil return line, and a solenoid valve 2 is provided on this branch line; the PLC controls the opening and closing of the power supply path of the proportional valve and the solenoid valve 2 through the sixth intermediate relay KA6 and the fifth intermediate relay KA5 in the weak current control circuit, respectively; the opening and closing of the proportional valve and the solenoid valve 2 are used to divert and reduce the pressure of the cleaning oil when the pressure at the front end of the two-stage filter in the oil outlet is too high or the pressure at the inlet of the hydraulic pipeline to be cleaned is too high.

[0064] The cooling fan is used to cool the cleaning oil. The fan motor is powered by the third main control circuit and its on / off state is controlled by the PLC through the second intermediate relay KA2 of the actuator. The feedback terminal of the second thermal relay FR2 is connected to the input terminal of the PLC of the control unit to detect whether the fan motor is overloaded and to provide the PLC with a fan motor overload protection signal. If the fan motor is overloaded, the fan motor stops, the red indicator light flashes, the alarm sounds, and the human-machine interface prompts that the fan motor is overloaded.

[0065] Thermocouples are installed inside the oil tank to measure the temperature of the cleaning oil. Temperature controller 1, based on the cleaning oil temperature, sends a heating signal to the PLC if the oil temperature is lower than the set value. The PLC then activates the coil of the third intermediate relay KA3, which in turn activates the SSR. The SSR conducts the heating circuit, and heater R1 heats the oil. When the temperature reaches the required value, temperature controller 1 disconnects the heating request signal to the PLC, and the PLC disconnects the coil of the third intermediate relay KA3, stopping the heating. This cycle repeats. If the temperature is too high and exceeds the required cleaning temperature, temperature controller 2 sends a cooling signal to the PLC. The PLC then activates the coil of the second intermediate relay KA2, which in turn activates the coil of the second contactor KM2. The contactor engages, and the fan starts to cool the oil, ensuring that the oil remains within the required cleaning temperature range during the circulating cleaning process. The PLC sends the oil temperature collected by the thermocouples to the human-machine interface for real-time display.

[0066] In this implementation, the specific steps for automating operations using the aforementioned aircraft hydraulic cleaning equipment control unit are as follows:

[0067] Step 1: Start-up preparation;

[0068] Check that the oil supply and return lines of the aircraft hydraulic cleaning equipment are connected correctly. If correct, power on the equipment and set the cleaning oil temperature and cleaning time on the human-machine interface. By default, the automatic / manual switch button is set to the automatic side, and the equipment enters self-test mode. The PLC checks whether the conditions of each input port meet the normal start-up and operation conditions, including whether the oil tank level is within the allowable range, whether the oil temperature is within the allowable range, and whether the thermal relay is normal. If the conditions are met, the operator presses the start button or the start button on the remote control to proceed to the next step.

[0069] Step 2: Circulating heating cleaning;

[0070] The PLC activates the KA1 coil, which in turn activates the KM1 coil. The KM1 contactor engages, and the oil pump pumps oil. The oil flows from the tank through the inlet filter, inlet shut-off valve, pre-pump filter, solenoid valve 1, oil pump, digital pressure sensor 1, two-stage filter, flow sensor 1, check valve, digital pressure sensor 2, and inlet oil pipe interface into the hydraulic pipeline to be cleaned. Then, the oil flows from the hydraulic pipeline to be cleaned through the outlet oil pipe interface, flow sensor 2, outlet shut-off valve, cooling fan, and outlet filter back to the tank, forming a cycle.

[0071] During the circulation of the cleaning oil in the pipeline, the thermocouple in the oil tank measures the temperature of the cleaning oil in real time. If the temperature of the cleaning oil is lower than the corresponding set value, the temperature controller 1 outputs a heating signal to the PLC. The PLC activates the KA3 coil, and the normally open contact of KA3 activates the SSR. The SSR conducts the heating circuit, and the heater R1 heats up, raising the temperature of the oil. When the temperature reaches the required value, the temperature controller 1 disconnects the heating request signal to the PLC, and the PLC disconnects the KA3 coil, stopping the heating. This cycle repeats. When the temperature is too high and exceeds the required cleaning temperature, the temperature controller 2 outputs a cooling signal to the PLC. The PLC activates the KA2 coil, and the normally open contact of KA2 activates the KM2 coil. The contactor engages, and the fan starts to cool down the oil. In this way, the oil is kept within the required temperature range during the circulating cleaning process.

[0072] Step 3: When the set cleaning time is reached, the alarm will sound. The operator will manually sample the cleaning oil through the sampling valve and check if the impurity content in the sample meets the cleaning end standard. If it does, press the stop button to stop the equipment and the cleaning is complete. If it does not meet the standard, press the start button to start the next round of cleaning.

[0073] Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of the present invention without departing from the principles and spirit of the present invention.

Claims

1. An automatic control unit for aircraft hydraulic cleaning equipment, characterized in that: It includes a control unit, an execution unit, and a sensing unit; The control unit includes a human-machine interface (HMI) for the aircraft hydraulic cleaning equipment, a programmable logic controller (PLC), and a switching power supply (SMPS). The PLC includes input and output terminals. The switching power supply converts 220V AC to 24V DC to power the HMI and the PLC output terminals of the aircraft hydraulic cleaning equipment. The HMI is connected to the PLC via a communication cable and displays the status parameters of the aircraft hydraulic cleaning equipment's automatic control unit, providing an interface for manual input of commands. The control unit receives all commands from the HMI and input signals from the PLC, and after logical judgment, sends control commands to the PLC output terminals. The actuator is connected to the output of the programmable logic controller (PLC) in the control unit via a communication cable. It is responsible for driving the actuators in the aircraft hydraulic cleaning equipment by activating a series of intermediate relays according to the control commands from the control unit. The actuator includes a first intermediate relay KA1, a second intermediate relay KA2, a third intermediate relay KA3, a fourth intermediate relay KA4, a fifth intermediate relay KA5, a sixth intermediate relay KA6, a red indicator light, a yellow indicator light, a green indicator light, and an alarm. The actuators in the aircraft hydraulic cleaning equipment include an oil pump motor for pumping cleaning oil, a cooling fan motor, and a heater R1 for heating the cleaning oil. The sensing unit is connected to the input terminal of the programmable logic controller (PLC) in the control unit via a communication cable, and is responsible for feeding back a series of sensor signals from the aircraft hydraulic cleaning equipment to the PLC in the control unit. The sensing unit includes an upper limit oil level sensor, a high oil level sensor, a lower limit operating oil level sensor, a first digital pressure sensor, a second digital pressure sensor, a fan thermal relay feedback terminal, an oil pump thermal relay feedback terminal, a first temperature controller, and a second temperature controller.

2. The automatic control unit of the aircraft hydraulic cleaning equipment according to claim 1, characterized in that: The control unit also includes a cabinet and a first circuit breaker QF1, a second circuit breaker QF2, a current transformer, a first contactor KM1, a second contactor KM2, a solid-state relay SSR, a first thermal relay FR1, a second thermal relay FR2, and a fuse FU1 installed in the cabinet. The human-machine interface for controlling the aircraft hydraulic cleaning equipment is located on the cabinet panel. The first and second temperature controllers are also located on the cabinet panel, while the PLC and switching power supply are located inside the cabinet. The first circuit breaker QF1 is a 4-pole switch, and the second circuit breaker QF2 is a 1-pole switch. After the cabinet is connected to 380V AC power through the first circuit breaker QF1, it is divided into three main control circuits. The first main control circuit supplies power to heater R1 after being protected by the first circuit breaker QF1, current transformer, solid-state relay SSR, and fuse FU1. The second main control circuit supplies power to oil pump motor after being protected by the first circuit breaker QF1, current transformer, first contactor KM1, and first thermal relay FR1. The third main control circuit supplies power to fan motor after being protected by the first circuit breaker QF1, current transformer, second contactor KM2, and second thermal relay FR2. The first intermediate relay KA1 is connected to the first contactor KM1, the second intermediate relay KA2 is connected to the second contactor KM2, and the third intermediate relay KA3 is connected to the solid-state relay SSR to form a secondary control circuit. The fourth intermediate relay KA4 is connected to the first solenoid valve, the fifth intermediate relay KA5 is connected to the second solenoid valve, and the sixth intermediate relay KA6 is connected to the proportional valve to form a low-voltage control circuit; the first solenoid valve, the second solenoid valve, and the proportional valve are the actuators in the aircraft hydraulic cleaning equipment. The second circuit breaker is connected to one of the live wires of the power supply connected to the first circuit breaker. The second circuit breaker supplies power to the secondary control circuit, PLC, and switching power supply in sequence. The switching power supply has a built-in rectifier circuit to convert 220V AC to 24V DC. The output port of the switching power supply is connected to the control human-machine interface and PLC output of the aircraft hydraulic cleaning equipment to supply power to the components of the control human-machine interface and PLC output of the aircraft hydraulic cleaning equipment. Below the human-machine interface on the cabinet panel is an operation panel, which includes an automatic / manual switch button, a start button, a stop button, and a reset button. These buttons are connected to the input terminals of the PLC in the control unit via communication cables. The automatic / manual switch button is used to switch control modes, the start button is used to start automatic operation, the stop button is used for emergency stop, and the reset button is used to unlock the program and return the system to its initial state after the abnormality is resolved.

3. The automatic control unit of the aircraft hydraulic cleaning equipment according to claim 2, characterized in that: The control unit also includes a remote controller, which is connected to the input terminal of the control unit PLC. The remote controller is equipped with the same automatic / manual switching button, start button, stop button, and reset button as the operation panel, and can remotely achieve the same functions as the control panel buttons.

4. The automatic control unit of the aircraft hydraulic cleaning equipment according to claim 2, characterized in that: In the secondary control circuit, the first intermediate relay KA1 is connected to the first contactor KM1 to control the on and off of the power supply path of the oil pump motor; the second intermediate relay KA2 is connected to the second contactor KM2 to control the on and off of the power supply path of the fan motor; and the third intermediate relay KA3 is connected to the solid-state relay SSR to control the on and off of the power supply path of the heater. In the weak current control circuit, the fourth intermediate relay KA4, the fifth intermediate relay KA5, and the sixth intermediate relay KA6 are respectively used to control the on and off of the power supply paths of the first solenoid valve, the second solenoid valve, and the proportional valve in the oil circuit.

5. The automatic control unit of the aircraft hydraulic cleaning equipment according to claim 1, characterized in that: The sensing unit also includes a first flow sensor and a second flow sensor. The PLC of the control unit is equipped with an AD module and a CPU module. The AD module is a digital-to-analog converter. The first flow sensor and the second flow sensor are connected to the AD module on the PLC of the control unit through cables. At the same time, the sampling data of the first flow sensor and the second flow sensor are converted by AD and connected to the control human-machine interface of the aircraft hydraulic cleaning equipment through the communication port of the CPU module via cables. The PLC sends the flow data collected by the two flow sensors to the control human-machine interface of the aircraft hydraulic cleaning equipment for real-time display.

6. The automatic control unit of the aircraft hydraulic cleaning equipment according to claim 1, characterized in that: The specific control of the actuator and the sensor in relation to the aircraft hydraulic cleaning equipment is as follows: The aircraft hydraulic cleaning equipment includes an oil tank, an oil outlet circuit, and an oil return circuit; the oil tank contains cleaning oil; the oil outlet circuit is used to lead the cleaning oil in the oil tank to the hydraulic pipeline to be cleaned; the oil return circuit is used to lead the cleaning oil in the hydraulic pipeline to be cleaned back to the oil tank. The oil removal circuit starts from the oil tank and is sequentially connected to the inlet filter, inlet shut-off valve, pre-pump filter, first solenoid valve, oil pump, first pressure sensor, two-stage filter, first flow sensor, check valve, second pressure sensor, and inlet oil pipe interface via pipelines; the inlet oil pipe interface is used to connect to the hydraulic pipeline inlet for cleaning. The return oil circuit starts from the outlet of the hydraulic pipeline to be cleaned and is connected in sequence to the outlet oil pipe interface, the second flow sensor, the outlet shut-off valve, the cooling fan, the outlet filter, and the oil tank pipeline; the outlet oil pipe interface is used to connect to the outlet of the hydraulic pipeline to be cleaned; a sampling valve is led out between the cooling fan and the outlet filter, which is used to finally detect whether the impurity content in the sample meets the cleaning completion standard by taking a sample from the cleaning oil. The oil pump is driven by an oil pump motor and is used to pump oil from the oil tank. The oil pump motor is powered by the second main control circuit and its on / off state is controlled by the PLC through the third intermediate relay KA3 of the actuator. The feedback terminal of the first thermal relay FR1 is connected to the input terminal of the control unit PLC to detect whether the oil pump motor is overloaded and to provide an oil pump motor overload protection signal to the PLC. If the oil pump motor is overloaded, the oil pump stops, the red indicator light flashes, the alarm sounds, and the human-machine interface prompts that the oil pump motor is overloaded. The heating tube is located at the bottom of the oil tank, and a heater R1 is arranged in the heating tube. The heater R1 is powered by the first main control circuit and its on / off state is controlled by the PLC through the third intermediate relay KA3 of the actuator. An upper limit oil level sensor is located at the oil tank inlet, while a high oil level sensor and a lower limit operating oil level sensor are located inside the oil tank to detect whether the oil level is within the allowable range. A first solenoid valve controls the opening and closing of the oil supply path, controlled by the PLC via the fourth intermediate relay KA4 of the actuator. A first pressure sensor is located at the oil pump outlet to monitor whether the oil pump pressure reaches the set value, thereby determining the pump's operation and shutdown. A first flow sensor transmits the real-time flow rate of the oil supply path to the PLC and the human-machine interface for real-time monitoring. A second pressure sensor is located at the inlet of the hydraulic pipeline to be cleaned to monitor whether the inlet oil pressure meets the cleaning pressure requirements. A second flow sensor transmits the real-time flow rate of the return oil path to the PLC and the human-machine interface for real-time monitoring. A branch line is provided between the first pressure sensor and the two-stage filter to connect the oil outlet to the oil return line, and a proportional valve is installed on this branch line; a branch line is provided between the two-stage filter and the first flow sensor to connect the oil outlet to the oil return line, and a second solenoid valve is installed on this branch line; the PLC controls the opening and closing of the power supply path of the proportional valve and the second solenoid valve through the sixth intermediate relay KA6 and the fifth intermediate relay KA5 in the weak current control circuit; the opening and closing of the proportional valve and the second solenoid valve are used to divert and reduce the pressure of the cleaning oil when the pressure at the front end of the two-stage filter in the oil outlet line is too high or the pressure at the inlet of the hydraulic pipeline to be cleaned is too high; The cooling fan is driven by a fan motor to cool the cleaning oil. The fan motor is powered by the third main control circuit and its on / off state is controlled by the PLC through the second intermediate relay KA2 of the actuator. The feedback terminal of the second thermal relay FR2 is connected to the input terminal of the control unit PLC to detect whether the fan motor is overloaded and to provide the PLC with a fan motor overload protection signal. If the fan motor is overloaded, the equipment stops, the red indicator light flashes, the alarm sounds, and the human-machine interface prompts that the fan motor is overloaded. Thermocouples are installed inside the oil tank to measure the temperature of the cleaning oil. The first temperature controller, based on the cleaning oil temperature, sends a heating signal to the PLC if the oil temperature is lower than the set value. The PLC then activates the coil of the third intermediate relay KA3, which in turn activates the SSR. The SSR conducts the heating circuit, and heater R1 heats the oil. When the temperature reaches the required value, the first temperature controller disconnects the heating request signal to the PLC, which then disconnects the coil of the third intermediate relay KA3, stopping the heating process. This cycle repeats. If the temperature is too high and exceeds the required cleaning temperature, the second temperature controller sends a cooling signal to the PLC. The PLC then activates the coil of the second intermediate relay KA2, which in turn activates the coil of the second contactor KM2. The contactor engages, and the fan starts to cool the oil, ensuring that the oil remains within the required cleaning temperature range during the circulating cleaning process. The PLC sends the oil temperature collected by the thermocouple to the human-machine interface for real-time display.

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