A kind of main pump motor liquid leakage intelligent monitoring device and method

Abstract

The application discloses a kind of main pump motor liquid leakage intelligent monitoring device and method, it is related to industrial process control and equipment state monitoring technical field, for solving the false alarm problem caused by the liquid type and leakage dynamic that existing liquid leakage intelligent monitoring technology cannot distinguish main pump motor liquid leakage.The device includes: through the oil pipeline and the oil drain tank of main pump motor connection of leakage liquid collection tank, liquid level signal acquisition module is arranged on the oil drain tank and leakage liquid collection tank, liquid level signal acquisition module is connected with DCS system, and the monitoring and diagnosis of leakage liquid state are carried out through DCS system.By the device and method, the leap of monitoring principle is realized, from static judgment upgrade to dynamic diagnosis;Multi-signal collaborative diagnostic logic is constructed, and the number of false alarms is reduced;Early warning mechanism is also established, and early warning is issued through rate anomaly when leakage is in initial stage and does not reach traditional alarm threshold.

Description

Technical Field

[0001] This invention belongs to the field of industrial process control and equipment condition monitoring technology, specifically relating to an intelligent monitoring device and method for liquid leakage in a main pump motor. Background Technology

[0002] Reliable monitoring of lubricating oil leakage in the main pump motor is a critical aspect of ensuring the safe operation of nuclear power units. Currently, the commonly used monitoring solution in this field is a static alarm system based on a tuning fork level switch. Its working principle is as follows: a tuning fork level switch is installed in the oil collection tank. When the liquid level in the tank rises to a preset height and submerges the tuning fork, a switch alarm signal is triggered by detecting changes in the vibration state of the tuning fork.

[0003] However, this existing technical solution has fundamental flaws due to its inherent technical principles: 1. Limited monitoring dimensions, unable to identify liquids: Tuning fork switches are essentially single-point, binary (present / absent) triggers. Their technical principle dictates that they can only sense whether the liquid level has reached a mechanical set point, completely unable to acquire any physical properties of the liquid (such as dielectric constant). This results in their inability to distinguish between accumulated lubricating oil and ambient condensate. This is the root cause of false alarms.

[0004] 2. Static judgment logic, lacking dynamic trend analysis: The existing system only alarms when the liquid level crosses a single static threshold, which is a kind of "post-event" judgment. Its technical solution does not include the logic for continuous monitoring and calculation of the liquid level change process (such as the rate of change), so it cannot issue early warnings through abnormal growth trends in the early stages of leakage, nor can it distinguish between rapid abnormal leakage and slow normal condensation accumulation from dynamic behavior.

[0005] 3. Poor anti-interference capability and low system reliability: The main pump room of a nuclear power plant is in a high-temperature and high-humidity environment all year round, and the condensate produced by the air cooler will continuously and slowly flow into the oil collection tank. This liquid accumulation under "normal operating conditions" will frequently trigger the tuning fork switch, resulting in a high false alarm rate in the system.

[0006] Taking a certain VVER nuclear power unit as an example, there have been over a hundred false alarms caused by condensate interference in the past decade. This not only increases the maintenance burden but also, due to the long-term and frequent false alarms, may lead to complacency among operators, thereby masking the true leakage signals and introducing potential safety risks. Existing improvement measures (such as optimizing installation location and strengthening dehumidification) are mostly passive protections and cannot fundamentally distinguish between leakage and condensation. Summary of the Invention

[0007] The purpose of this invention is to provide an intelligent monitoring device and method for liquid leakage in a main pump motor, which solves the problem of false alarms caused by the inability of existing liquid leakage monitoring technologies to distinguish the type of liquid and the dynamics of leakage in the main pump motor.

[0008] The technical solution adopted by the present invention to solve its technical problem is: an intelligent monitoring device for liquid leakage of a main pump motor, wherein the device includes: a leakage liquid collection tank connected to the unloading tank of the main pump motor through an oil inlet pipeline, and a liquid level signal acquisition module is provided on both the unloading tank and the leakage liquid collection tank. The liquid level signal acquisition module is connected to a DCS system, and the leakage liquid status is monitored and diagnosed through the DCS system.

[0009] The above-mentioned intelligent monitoring device for liquid leakage in a main pump motor includes a liquid level signal acquisition module comprising: a guided wave radar level gauge installed on the top of the leaking liquid collection tank and a tuning fork level switch installed in the oil collection tank of the main pump motor.

[0010] In the aforementioned intelligent monitoring device for liquid leakage from a main pump motor, the leakage liquid collection tank is connected to the drain line on the main pump motor unloading tank via an oil inlet pipeline. One end of the oil inlet pipeline is connected to the drain line, and the other end extends to the bottom of the leakage liquid collection tank.

[0011] The above-mentioned intelligent monitoring device for liquid leakage of main pump motor includes an oil inlet pipe clamp at the top of the leaked liquid collection tank, which fixes the oil inlet pipeline to ensure the axiality and stability of the oil inlet pipeline.

[0012] The above-mentioned intelligent monitoring device for liquid leakage of a main pump motor includes a leakage liquid collection tank comprising: a galvanized steel pipe serving as the main support component of the leakage collection tank; the galvanized steel pipe is vertically arranged; the bottom end of the galvanized steel pipe is fixedly connected to a horizontally arranged carbon steel base by welding; and an oil drain valve is also provided at the bottom of the leakage liquid collection tank.

[0013] The above-mentioned intelligent monitoring device for liquid leakage of main pump motor includes a guided wave radar level gauge on the top of the leaking liquid collection tank, comprising: an angle steel fixedly installed along the top edge of the leaking liquid collection tank; the guided wave radar level gauge is fixed to the top of the leaking liquid collection tank by the angle steel; a fixing nut for fixing the waveguide rod of the guided wave radar level gauge is provided on the angle steel; the upper part of the guided wave radar level gauge is a wiring cavity; a connecting cable is led out from the wiring cavity and connected to the DCS system.

[0014] In the aforementioned intelligent monitoring device for liquid leakage from a main pump motor, the leaked liquid collection tank is vertically fixed to a C-shaped channel steel by a fixing clamp, and one end of the C-shaped channel steel is fixedly connected to a reserved steel component on the wall.

[0015] A method for intelligent monitoring of liquid leakage in a main pump motor, used to implement the aforementioned intelligent monitoring device for liquid leakage in a main pump motor, the method comprising: Step 1: The leaked liquid and condensate are buffered and temporarily stored in the leaked liquid collection tank. During this process, the liquid level status signal is collected by the guided wave radar level gauge and tuning fork level switch of the liquid level signal acquisition module and transmitted to the DCS system. Step 2: The DCS system calculates the dynamic rate of change of the leaking liquid in real time based on the continuous analog signal collected by the guided wave radar level gauge. Step 3: The DCS system is set with a leakage rate alarm threshold. The DCS system combines the dynamic change rate of the leaking liquid with the static switching signal collected by the tuning fork level switch to make a graded alarm mechanism. Step 4: When the dynamic change rate of the leaking liquid calculated by the DCS system exceeds the set threshold of 0.3 mm / s, but the switching signal of the tuning fork level switch is not triggered, the system generates a Level W warning. The Level W warning indicates that there is an abnormal rapid liquid level rise trend, notifying the operators to pay attention and conduct preventive inspections, thus achieving early warning. Step 5: When the dynamic change rate of the leaking liquid calculated by the DCS system exceeds the set threshold of 0.3 mm / s, and the switching signal of the tuning fork level switch is triggered, the system generates a Class A warning. The Class A alarm indicates that a real leak has occurred and intervention measures must be taken immediately.

[0016] The above-mentioned intelligent monitoring method for liquid leakage in a main pump motor includes a step two where the DCS system calculates the dynamic rate of change of the leaking liquid in real time, acquires the reading L(t) of the guided wave radar level gauge through a fixed period T, and then: The leakage rate V is calculated in real time, L(t) is the liquid level value at the current sampling time, L(tT) is the liquid level value at the previous sampling time, and the fixed period T is set to be less than or equal to 400ms.

[0017] Compared with the prior art, the beneficial effects of the present invention are as follows: The intelligent monitoring device and method for liquid leakage of the main pump motor provided by the present invention, on the one hand, realizes a leap in monitoring principle, upgrading from static judgment to dynamic diagnosis, and realizing the distinction between slow condensation accumulation and rapid abnormal leakage; on the other hand, it constructs a multi-signal collaborative diagnostic logic, reducing the number of false alarms and improving alarm reliability; finally, it establishes a hierarchical early warning mechanism, which issues an early warning through abnormal rate at the initial stage of leakage and before the traditional alarm threshold is reached, supporting preventive maintenance and changing passive response to active intervention. Attached Figure Description

[0018] Figure 1 The figure shown is a schematic diagram of the overall structure of the intelligent monitoring device for liquid leakage of a main pump motor according to the present invention. Figure 2 The diagram shown is a structural diagram of the leakage collection tank and guided wave radar level gauge of a main pump motor liquid leakage intelligent monitoring device according to the present invention. Figure 3 The diagram shown is a logical flowchart of a method for intelligent monitoring of liquid leakage in a main pump motor according to the present invention.

[0019] Reference numerals: 1. Drainage pipeline; 2. Inlet pipeline; 3. Inlet pipe clamp; 4. Leakage liquid collection tank; 5. C-shaped channel steel; 6. Fixing clamp; 7. Oil collection tray; 8. Carbon steel base; 9. Fixing nut; 10. Wall; 11. Guided wave radar level gauge; 12. Wiring cavity; 13. Angle steel; 14. Guide rod; 15. Drain valve; 16. Reserved steel parts; 17. Connecting cable; 18. Tuning fork level switch; 19. Main pump motor; 20. DCS system. Detailed Implementation

[0020] To address the problem of false alarms caused by the inability of existing intelligent liquid leakage monitoring technologies to distinguish the type and dynamics of liquid leakage from the main pump motor, this invention provides an intelligent monitoring device and method for liquid leakage from the main pump motor. The intelligent monitoring device for liquid leakage from the main pump motor is as follows: Figure 1 , Figure 2 As shown, the device includes a leaking liquid collection tank 4 connected to the unloading tank of the main pump motor 19 via an oil inlet pipeline 2. Both the unloading tank and the leaking liquid collection tank 4 are equipped with liquid level signal acquisition modules. These modules acquire liquid level information within the intelligent liquid leakage monitoring device. Each liquid level signal acquisition module includes a guided wave radar level gauge 11 mounted on the top of the leaking liquid collection tank 4 and a tuning fork level switch 18 mounted in the oil collection tank of the main pump motor 19. The liquid level signal acquisition modules are connected to a DCS system 20 for real-time monitoring and diagnosis of the leaking liquid status. The leaking liquid collection tank 4 is connected to the drain pipeline 1 on the unloading tank of the main pump motor 19 via the oil inlet pipeline 2. One end of the oil inlet pipeline 2 is connected to the drain pipeline 1, and the other end extends to the bottom of the leaking liquid collection tank 4. An oil inlet clamp 3 is installed on the top of the leaking liquid collection tank 4 to fix the oil inlet pipeline 2, ensuring its axiality and stability. The oil inlet line 2 is made of oil-resistant and high-temperature resistant hose, preferably a transparent fluororubber hose. Its end can be cut into a 45° bevel to avoid the liquid directly impacting the tank wall and causing splashing or foaming, ensuring a stable liquid surface and facilitating accurate measurement.

[0021] The leaking liquid collection tank 4 is used to receive and buffer the accumulated leaking liquid and condensate. Its structural design allows it to accommodate the slowly accumulating condensate under normal operating conditions while maintaining sufficient sensitivity to level changes caused by abnormal leaks. The leaking liquid collection tank 4 includes a galvanized steel pipe as the main supporting component, which possesses excellent corrosion resistance and structural strength. The galvanized steel pipe is vertically installed, and its bottom end is welded to a horizontally installed carbon steel base 8. An oil drain valve 15 is also installed at the bottom of the leaking liquid collection tank 4. An oil collection tray 7 is installed at the lower part of the carbon steel base 8. The leaking liquid collection tank 4 is vertically fixed to a C-shaped channel steel 5 by fixing clamps 6. One end of the C-shaped channel steel 5 is fixedly connected to a reserved steel part 16 on the wall 10. The tank body of the leaking liquid collection tank 4 adopts a cylindrical structure, and its capacity is sufficient to accommodate the condensate normally generated during a major overhaul cycle while maintaining sufficient monitoring sensitivity to level changes caused by actual leaks.

[0022] The guided wave radar level gauge 11 on top of the leaking liquid collection tank 4 includes: an angle steel 13 fixedly installed along the top edge of the leaking liquid collection tank 4; the guided wave radar level gauge 11 is fixed to the top of the leaking liquid collection tank 4 by the angle steel 13; a fixing nut 9 for fixing the waveguide rod 14 of the guided wave radar level gauge 11 is provided on the angle steel 13; the upper part of the guided wave radar level gauge 11 is a wiring cavity 12, from which a connecting cable 17 is led out to connect to the DCS system 20. The guided wave radar level gauge 11 can continuously measure the liquid level in the leaking liquid collection tank 4 in real time and output a 4-20mA standard analog signal. In the high temperature and humidity environment of nuclear power plants, where condensation is easily generated, the guided wave radar level gauge 11, based on the time domain reflection principle (TDR), is less affected by small changes in steam, temperature gradient, and dielectric constant of the medium, and is insensitive to adhering substances. Compared with ultrasonic or capacitive level gauges, it has higher measurement accuracy and long-term stability in this device.

[0023] The intelligent monitoring device for liquid leakage in the main pump motor provided by this invention is an enhancement and intelligent upgrade of the original monitoring system. While retaining the original switching monitoring circuit of the tuning fork level switch 18, this intelligent monitoring device adds a parallel analog monitoring and diagnostic circuit based on the leaking liquid collection tank 4 and the guided wave radar level gauge 11. The fusion judgment logic of the two signals is implemented in the DCS system 20. The intelligent monitoring device is installed near the main pump motor 19 in a convenient location for pipe connection, observation, and maintenance. The leaking liquid collection tank 4 is reliably fixed to a special bracket pre-welded to the ground via bolts through its carbon steel base 8, and calibrated using a level to ensure the tank is strictly vertical. The verticality deviation must be controlled within 1° to ensure the accuracy of the guided wave radar level gauge measurement results.

[0024] By integrating the static switching signal of the tuning fork level switch with the dynamic analog data of the guided wave radar level gauge 11, a multi-signal collaborative diagnostic mechanism is constructed to achieve accurate identification and early warning of real lubricating oil leaks, and ultimately establish a reliable, intelligent leak monitoring system with gradient response capability.

[0025] The intelligent monitoring method for liquid leakage in the main pump motor is used to implement the aforementioned intelligent monitoring device for liquid leakage in the main pump motor. The logic flowchart of this method is as follows: Figure 3 As shown, the intelligent monitoring method for liquid leakage in the main pump motor includes: Step 1: The leaked liquid and condensate are buffered and temporarily stored in the leaked liquid collection tank 4. During this process, the liquid level status signal is collected by the guided wave radar level gauge 11 and the tuning fork level switch 18 of the liquid level signal acquisition module and transmitted to the DCS system 20. Step 2: The DCS system 20 calculates the dynamic rate of change of the leaking liquid in real time based on the continuous analog signal collected by the guided wave radar level gauge 11. Step 3: The DCS system 20 is set with a leakage rate alarm threshold. The DCS system 20 combines the dynamic change rate of the leaking liquid with the static switching signal collected by the tuning fork level switch 18 to make a graded alarm mechanism judgment. Step 4: When the dynamic change rate of the leaking liquid calculated by the DCS system 20 exceeds the set threshold of 0.3 mm / s, but the switching signal of the tuning fork level switch 18 is not triggered, the system generates a level W warning. The level W warning indicates that there is an abnormal rapid liquid level rise trend, notifying the operators to pay attention and carry out preventive inspections, thus achieving early warning. Step 5: When the dynamic change rate of the leaking liquid calculated by the DCS system 20 exceeds the set threshold of 0.3 mm / s, and the switching signal of the tuning fork level switch 18 is triggered, the system generates a Class A warning. The Class A alarm indicates that a real leak has occurred and intervention measures must be taken immediately.

[0026] In step two, the DCS system 20 calculates the dynamic change rate of the leaking liquid in real time, and acquires the reading L(t) of the guided wave radar level gauge through a fixed period T, and then... The leakage rate V is calculated in real time, L(t) is the liquid level value at the current sampling time, L(tT) is the liquid level value at the previous sampling time, and the fixed period T is set to be less than or equal to 400ms.

[0027] The leakage rate alarm threshold is crucial for ensuring the accuracy of the system's judgment, and this threshold was determined through field simulation tests. The tests simulated two typical leakage conditions: "linear flow leakage," simulating a severe pipe rupture, and "dripping flow leakage," simulating a minor rupture. By controlling the flow rate of the injected leakage liquid into the collection tank 4 and simultaneously recording the liquid level changes, the leakage rates under different modes were obtained. The test data are shown in Table 1.

[0028] Table 1 Simulated Leakage Test Data Based on experimental data and considering the balance between identifying actual leaks and avoiding false alarms, the leak rate alarm threshold was set at 0.3 mm / s. This threshold effectively detects abnormally rapid leaks while filtering out slow condensate buildup.

[0029] It should be noted that the combination of the technical features in the embodiments of the present invention is not limited to the combination methods described in the embodiments of the present invention or the combination methods described in the specific embodiments. All technical features described in the present invention can be freely combined or combined in any way, unless there is a contradiction between them.

[0030] 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, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A smart monitoring device for liquid leakage in a main pump motor, characterized in that, The device includes a leak liquid collection tank (4) connected to the unloading tank of the main pump motor (19) via an oil inlet pipeline (2). Both the unloading tank and the leak liquid collection tank (4) are equipped with liquid level signal acquisition modules. The liquid level signal acquisition modules are connected to the DCS system (20) to monitor and diagnose the state of the leak liquid through the DCS system (20).

2. The intelligent monitoring device for liquid leakage of a main pump motor according to claim 1, characterized in that, The liquid level signal acquisition module includes: a guided wave radar level gauge (11) installed on the top of the leaking liquid collection tank (4) and a tuning fork level switch (18) installed in the oil collection tank of the main pump motor (19).

3. The intelligent monitoring device for liquid leakage of a main pump motor according to claim 1, characterized in that, The leaked liquid collection tank (4) is connected to the oil discharge line (1) on the oil unloading tank of the main pump motor (19) via the oil inlet line (2). One end of the oil inlet line (2) is connected to the oil discharge line (1), and the other end extends to the bottom of the leaked liquid collection tank (4).

4. The intelligent monitoring device for liquid leakage of a main pump motor according to claim 1 or 3, characterized in that, The top of the leaked liquid collection tank (4) is equipped with an oil inlet clamp (3), which fixes the oil inlet pipeline (2) to ensure the axiality and stability of the oil inlet pipeline (2).

5. The intelligent monitoring device for liquid leakage of a main pump motor according to claim 1, characterized in that, The leaked liquid collection tank (4) includes: a galvanized steel pipe as the main support of the leaked liquid collection tank (4), the galvanized steel pipe is set vertically, the bottom end of the galvanized steel pipe is fixedly connected to the horizontally set carbon steel base (8) by welding, and the bottom of the leaked liquid collection tank (4) is also provided with an oil drain valve (15).

6. The intelligent monitoring device for liquid leakage of a main pump motor according to claim 2, characterized in that, The guided wave radar level gauge (11) on the top of the leaked liquid collection tank (4) includes: an angle steel (13) fixedly installed along the top edge of the leaked liquid collection tank (4), the guided wave radar level gauge (11) is fixed to the top of the leaked liquid collection tank (4) by the angle steel (13), the angle steel (13) is provided with a fixing nut (9) for fixing the waveguide rod (14) of the guided wave radar level gauge (11), the upper part of the guided wave radar level gauge (11) is a wiring cavity (12), and a connecting cable (17) is led out from the wiring cavity (12) to connect to the DCS system (20).

7. The intelligent monitoring device for liquid leakage of a main pump motor according to claim 1, characterized in that, The leaked liquid collection tank (4) is fixed to the C-shaped channel steel (5) by a fixing clamp (6), and one end of the C-shaped channel steel (5) is fixedly connected to the reserved steel part (16) on the wall (10).

8. A method for intelligent monitoring of liquid leakage in a main pump motor, characterized in that, For implementing the intelligent monitoring device for liquid leakage of a main pump motor as described in any one of claims 1-7, wherein the intelligent monitoring method for liquid leakage of a main pump motor includes: Step 1: The leaked liquid and condensate are buffered and temporarily stored in the leaked liquid collection tank (4). During this process, the liquid level status signal is collected by the guided wave radar level gauge (11) and tuning fork level switch (18) of the liquid level signal acquisition module and transmitted to the DCS system (20). Step 2: The DCS system (20) calculates the dynamic change rate of the leaking liquid in real time based on the continuous analog signal collected by the guided wave radar level gauge (11). Step 3: The DCS system (20) has a leakage rate alarm threshold. The DCS system (20) combines the dynamic change rate of the leaking liquid with the static switching signal collected by the tuning fork level switch (18) to make a graded alarm mechanism judgment. Step 4: When the dynamic change rate of the leaking liquid calculated by the DCS system (20) exceeds the set threshold of 0.3 mm / s, but the switching signal of the tuning fork level switch (18) is not triggered, the system generates a W-level warning. The W-level warning indicates that there is an abnormal rapid liquid level rise trend, notifying the operators to pay attention and carry out preventive inspections to achieve early warning. Step 5: When the dynamic change rate of the leaking liquid calculated by the DCS system (20) exceeds the set threshold of 0.3 mm / s, and the switching signal of the tuning fork level switch (18) is triggered, the system generates a Class A warning. The Class A alarm indicates that a real leak has occurred and intervention measures need to be taken immediately.

9. The intelligent monitoring method for liquid leakage in a main pump motor according to claim 8, characterized in that, In step two, the DCS system (20) calculates the dynamic change rate of the leaking liquid in real time, and collects the reading L(t) of the guided wave radar level gauge by setting a fixed period T, and then... The leakage rate V is calculated in real time, L(t) is the liquid level value at the current sampling time, L(tT) is the liquid level value at the previous sampling time, and the fixed period T is set to be less than or equal to 400ms.

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