A system and method for online monitoring of steam trap status

Abstract

This invention discloses an online monitoring system and method for the status of steam traps, including a steam trap management module, a steam trap detection module, an intelligent front-end module, a data acquisition interface module, and a back-end computing service module. The steam trap management module controls and connects to the steam trap detection module, and the steam trap detection module controls and connects to the intelligent front-end module. This invention collects downstream pipeline temperature data through the steam trap detection module, calculates the heat conduction relationship in the pipeline based on the data, establishes a model of the temperature relationship between the current moment and the previous moment, and then uses the two-point method and the least squares method to fit the downstream temperature drop trend of the steam trap. Based on the fitting results, a data-driven temperature drop model is established. Finally, the status of the steam trap is determined and managed based on the deviation between the model and the actual temperature change, improving the convenience of valve status assessment and management and extending the service life of the steam trap.

Description

Technical Field

[0001] This invention relates to the field of steam trap status monitoring technology, specifically to an online steam trap status monitoring system and method. Background Technology

[0002] Generator sets have a large number of drain valves. Considering investment costs, these valves are basically local valves, and the valve status is judged by the experience of the operators. The phenomenon of misjudgment is common. Changing to electric valves is impractical. Once the unit is running at high load, the valves are not closed tightly, which not only affects the life of the valves themselves, but also seriously affects the safe operation of the unit and causes a lot of energy waste. Therefore, it is necessary to design an online monitoring system and method for drain valve status to replace human experience in judging the valve status, improve the convenience of valve status assessment and management, and extend the service life of drain valves. Summary of the Invention

[0003] The purpose of this invention is to provide an online monitoring system and method for the status of steam traps to solve the problems mentioned in the background art.

[0004] To achieve the above objectives, the present invention provides the following technical solution: an online monitoring system for the status of steam traps, comprising a steam trap management module, a steam trap detection module, an intelligent front-end module, a data acquisition interface module, and a back-end computing service module. The steam trap management module controls and connects to the steam trap detection module, and the steam trap detection module controls and connects to the intelligent front-end module. The intelligent front-end module controls and connects to the data acquisition interface module, and the data acquisition interface module controls and connects to the back-end computing service module.

[0005] A method for online monitoring of steam trap status includes the following steps: Step 1, steam trap data acquisition; Step 2, data transmission; Step 3, pipeline heat exchange analysis; Step 4, temperature relationship analysis; Step 5, cooling model establishment; Step 6, valve status determination.

[0006] In step one above, the drain valve detection module detects and collects the pipe outer wall temperature t2 and the ambient air temperature t. a The temperature t0 of the fluid inside the pipe is then collected by the steam trap detection module, along with the pipe outer wall temperature t2 and the ambient air temperature t3. a The temperature t0 of the fluid inside the pipeline is transmitted to the intelligent front-end module for data display.

[0007] In step two above, the pipe outer wall temperature t2 and the surrounding air temperature t are respectively collected through the data acquisition interface module. a The temperature t0 of the fluid inside the pipe is transmitted to the background computing service module;

[0008] In step three above, the background calculation service module receives the pipe outer wall temperature t2 and the surrounding air temperature t a The temperature t0 of the fluid inside the pipe is determined. Then, the natural convection heat transfer relationship between the insulation layer and the surrounding air is analyzed. Next, the heat conduction relationship between the insulation layer, the inner wall of the pipe and the outer wall is analyzed. Finally, the forced convection heat transfer relationship of the fluid inside the pipe is analyzed.

[0009] In step four above, the background calculation service module combines the natural convection heat transfer relationship between the insulation layer and the surrounding air, the heat conduction relationship between the insulation layer, the inner wall and the outer wall of the pipe, and the forced convection heat transfer relationship of the fluid inside the pipe analyzed in step three to establish a model of the temperature relationship between the current moment and the previous moment.

[0010] In step five above, the background calculation service module (5) analyzes and organizes the historical data collected by the temperature measuring points arranged in the field drainage pipes, and uses the two-point method and the least squares method to fit the temperature drop trend of some drainage valves. Based on the temperature relationship model between the current time and the previous time obtained in step four, a data-driven temperature drop model is established. Then, the temperature drop model after the drainage valve is numerically expressed and displayed to obtain the normalized expression of the transfer function.

[0011] In step six above, a finite state machine model is introduced through the background calculation service module, and the valve state is determined by combining the unit impulse response expression and the normalized expression of the transfer function obtained in step five.

[0012] Preferably, in step three, the formula for expressing the natural convection heat transfer relationship between the insulation layer and the surrounding air is: Where d3 is the outer diameter of the insulation layer; l is the length of the control volume used in the calculation; h1 is the heat transfer coefficient; and the formula for calculating h1 is: Where λa is the thermal conductivity of air; N u Given the Nusselt number, the heat transfer between the insulation layer and the surrounding air is considered to be natural convection heat transfer in a large horizontal tube space, therefore N can be obtained. u =C(G r P r )n, where P r The value of b is the Prandtl number; the value of b depends on whether the flow is laminar or turbulent; G r It is a Grashof number, and G r The formula for calculation is: Where g is the acceleration due to gravity, α = 1 / T, T is the absolute temperature of the surrounding air, and Δt = t³ - t a μ represents aerodynamic viscosity.

[0013] Preferably, in step three, the heat conduction between the insulation layer, the inner wall of the pipe, and the outer wall can be approximated as a heat conduction problem of a single-layer homogeneous cylindrical wall, and the formula for expressing the heat conduction relationship is: In the formula λ b d1 is the thermal conductivity of the insulation layer; d2 is both the inner diameter of the insulation layer and the outer diameter of the pipe; similarly, the heat dissipation of the pipe can be approximated as a heat conduction problem of a single-layer homogeneous cylindrical wall, and its heat conduction formula is: In the formula λ g d1 is the thermal conductivity of the pipe; d2 is the inner diameter of the pipe.

[0014] Preferably, in step three, the forced convection heat transfer relationship of the fluid inside the pipe is due to the forced convection heat transfer of the steam or water flow inside the pipe, and its expression is as follows: Where ρ is the fluid density; v is the fluid velocity; h2 is the heat transfer coefficient between the internal fluid and the pipe wall; and t0 is the average temperature of the fluid in the control volume.

[0015] Preferably, in step four, the process of establishing the temperature relationship model between the current moment and the previous moment is as follows: First, the heat exchange process between the insulation layer and the inner and outer walls of the pipe is ignored, and only the heat transfer between the working fluid and the external environment is considered. The temperature relationship model between the current moment and the previous moment is regarded as a first-order inertial element. Then, the heat transfer of the working fluid to the pipe wall in the pipe is calculated by convective heat transfer, and the expression is: Q1=h1Aη(t0-t i Next, the heat transfer from the compressed gas inside the pipe to the pipe wall is calculated using convective heat transfer, and its expression is: Q2=h2Aη(t i -T); the temperature difference relationship is: Q1-Q2=cm(t) i+1 -t i Then, the relationship model between the current temperature and the previous temperature can be obtained as follows: Where A is the convective heat transfer contact area, and A = 2πrl, T is the ambient temperature, c is the specific heat capacity of the pipe material, and d t The time interval is 10 seconds, m is the mass of the pipe per unit length, and m = 2πrlρ.

[0016] Preferably, in step five, the names of the drain valves are as follows: drain pneumatic valve after the check valve of the fourth pump to A small turbine, main drain valve after the outlet electric valve of A steam pump, main steam main pipe water supply pneumatic valve, and drain valve from the outlet check valve of B steam pump to the outlet electric valve to the unpressurized drain valve. The normalized expression of the transfer function of the drain pneumatic valve after the check valve of the fourth pump to A small turbine is G(s) = 0.0361 / (s + 0.001805); the drain valve after the outlet electric valve of A steam pump... The normalized expression for the transfer function of the main valve is G(s) = 0.0195 / (s + 0.000972); the normalized expression for the transfer function of the pneumatic valve for water supply in the main steam pipe is G(s) = 0.00596 / (s + 0.000297); the normalized expression for the transfer function from the outlet check valve of steam pump B to the outlet electric valve to the unpressurized discharge valve is G(s) = 0.00978 / (s + 0.000489).

[0017] Preferably, in step six, the valve status is divided into closed, open, fully open, intermediate, and closed states. When the steam trap is 100% closed, with an opening of 0 degrees and no steam leakage, it is determined to be in the closed state when steam condensation stops. At this time, the unit operates normally under a certain load. The temperature value at the measuring point after the steam trap maintains a trend of small fluctuations and a relatively small temperature reading over a period of time. That is, the rate of temperature change remains at or below a small constant value over a period of time, and the temperature reading is close to the ambient temperature. Under this state, steam leakage may occur. If the temperature reading at the measuring point is abnormal, such as an increase or a sustained high temperature, the valve needs to be closed. When the steam trap gradually opens and the flow of condensate increases, it is considered to be in a positive open state. At this time, the temperature reading at the measuring point downstream of the steam trap will show a continuous increase over a period of time, gradually changing from a lower temperature to a higher temperature, but never reaching the steam temperature. That is, the rate of temperature change remains at or above a constant value and shows a positive correlation, with the temperature reading exceeding the initial value. When the steam trap is 100% open... When the steam trap opening is 1, drainage is normal, and the drainage volume reaches its maximum, it is determined to be in a fully open state. At this time, the unit operates normally under a certain load. The temperature value at the measuring point downstream of the steam trap maintains a relatively large trend over a period of time, meaning the rate of temperature change remains at or below a small constant value, and the temperature reading is close to the steam temperature. When the steam trap is between closed and open, with the opening reaching a certain value and maintained, drainage is normal, and it is determined to be in an intermediate state. At this time, the temperature value at the measuring point downstream of the steam trap maintains a relatively large trend over a period of time. The temperature reading shows a trend of change towards a relatively small value, meaning that the rate of change of the temperature value remains or is less than a small constant value over a period of time, and the temperature reading is between the ambient temperature and the steam temperature. When the steam trap is gradually closed and the opening degree gradually decreases, the amount of condensate passing through decreases, which is determined to be the positive closed state. At this time, the temperature value at the measuring point after the steam trap shows a continuous decreasing process over a period of time, gradually changing from a higher temperature to a lower temperature, but never reaching the ambient temperature. That is, the rate of change of the temperature value over a period of time remains or is less than a constant value and shows a negative correlation, and the temperature reading is less than the initial value.

[0018] Compared with the prior art, the beneficial effects of the present invention are as follows: The online monitoring system and method for the status of a steam trap collects temperature data of the pipeline downstream of the valve through a steam trap detection module. Then, based on the data, it calculates the natural convection heat transfer relationship between the insulation layer and the surrounding air, the heat conduction relationship between the insulation layer, the inner wall and the outer wall of the pipeline, and the forced convection heat transfer relationship of the fluid inside the pipeline. After that, it establishes a model of the relationship between the current temperature and the previous temperature. Then, it uses the two-point method and the least squares method to fit the trend of the temperature drop change downstream of the steam trap. Based on the model of the temperature relationship between the current temperature and the previous temperature, it establishes a data-driven temperature drop model and judges and manages the status of the steam trap according to the model, which improves the convenience of valve status evaluation and management and extends the service life of the steam trap. Attached Figure Description

[0019] Figure 1 This is a system flowchart of the present invention;

[0020] Figure 2 This is a system framework diagram of the present invention;

[0021] Figure 3 This is a flowchart of the method of the present invention;

[0022] In the diagram: 1. Steam trap management module; 2. Steam trap detection module; 3. Intelligent front-end module; 4. Data acquisition interface module; 5. Back-end computing service module. Detailed Implementation

[0023] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0024] Please see Figure 1-2 The present invention provides an embodiment of an online monitoring system for the status of a steam trap, comprising a steam trap management module 1, a steam trap detection module 2, an intelligent front-end module 3, a data acquisition interface module 4, and a back-end computing service module 5. The steam trap management module 1 controls and connects to the steam trap detection module 2, and the steam trap detection module 2 controls and connects to the intelligent front-end module 3. The intelligent front-end module 3 controls and connects to the data acquisition interface module 4, and the data acquisition interface module 4 controls and connects to the back-end computing service module 5.

[0025] Please see Figure 3The present invention provides an embodiment of an online monitoring method for the status of a steam trap, comprising the following steps: Step 1, steam trap data acquisition; Step 2, data transmission; Step 3, pipeline heat exchange analysis; Step 4, temperature relationship analysis; Step 5, cooling model establishment; Step 6, valve status determination.

[0026] In step one above, the drain valve detection module 2 detects and collects the pipe outer wall temperature t2 and the ambient air temperature t. a The temperature t0 of the fluid inside the pipe is then collected by the steam trap detection module 2, which in turn collects the temperature t2 of the outer wall of the pipe and the ambient air temperature t0. a The temperature t0 of the fluid inside the pipeline is transmitted to the intelligent front-end module 3 for data display.

[0027] In step two above, the pipe outer wall temperature t2 and the surrounding air temperature t are respectively collected through the data acquisition interface module 4. a The temperature t0 of the fluid inside the pipe is transmitted to the background computing service module 5;

[0028] In step three above, the background calculation service module 5 receives the pipe outer wall temperature t2 and the surrounding air temperature t a The temperature t0 of the fluid inside the pipe is determined. Then, the natural convection heat transfer relationship between the insulation layer and the surrounding air is analyzed. Next, the heat conduction relationship between the insulation layer, the inner wall of the pipe, and the outer wall is analyzed. Finally, the forced convection heat transfer relationship of the fluid inside the pipe is analyzed. The formula for expressing the natural convection heat transfer relationship between the insulation layer and the surrounding air is: Where d3 is the outer diameter of the insulation layer; l is the length of the control volume used in the calculation; h1 is the heat transfer coefficient; and the formula for calculating h1 is: Where λa is the thermal conductivity of air; N u Given the Nusselt number, the heat transfer between the insulation layer and the surrounding air is considered to be natural convection heat transfer in a large horizontal tube space, therefore N can be obtained. u =C(G r P r )n, where P r The Prandtl number; n is determined based on laminar and turbulent flow conditions; G r It is a Grashof number, and G r The formula for calculation is: Where g is the acceleration due to gravity, α = 1 / T, T is the absolute temperature of the surrounding air, and Δt = t³ - t a μ is the aerodynamic viscosity; the heat conduction between the insulation layer, the inner wall of the pipe, and the outer wall can be approximated as a heat conduction problem of a single-layer homogeneous cylindrical wall, and the formula for expressing the heat conduction relationship is: In the formula λ bd1 is the thermal conductivity of the insulation layer; d2 is both the inner diameter of the insulation layer and the outer diameter of the pipe; similarly, the heat dissipation of the pipe can be approximated as a heat conduction problem of a single-layer homogeneous cylindrical wall, and its heat conduction formula is: In the formula λ g d is the thermal conductivity of the pipe; d1 is the inner diameter of the pipe; the forced convection heat transfer relationship of the fluid inside the pipe is as follows: Since the flow of steam or water inside the pipe is forced convection heat transfer, its expression is: Where ρ is the fluid density; v is the fluid velocity; h2 is the heat transfer coefficient between the internal fluid and the pipe wall; and t0 is the average temperature of the fluid in the control volume.

[0029] In step four above, the background calculation service module 5, combining the natural convection heat transfer relationship between the insulation layer and the surrounding air, the heat conduction relationship between the insulation layer, the inner wall and the outer wall of the pipe, and the forced convection heat transfer relationship of the fluid inside the pipe analyzed in step three, establishes a model of the temperature relationship between the current moment and the previous moment. The process of establishing the temperature relationship model between the current moment and the previous moment is as follows: First, ignore the heat transfer process between the insulation layer and the inner and outer walls of the pipe, and only consider the heat transfer between the working fluid and the external environment. Treat the temperature relationship model between the current moment and the previous moment as a first-order inertial element. Then, calculate the heat transfer of the working fluid inside the pipe to the pipe wall in the form of convection heat transfer, and the expression is: Q1=h1Aη(t0-t i Next, the heat transfer from the compressed gas inside the pipe to the pipe wall is calculated using convective heat transfer, and its expression is: Q2=h2Aη(t i -T); the temperature difference relationship is: Q1-Q2=cm(t) i+1 -t i Then, the relationship model between the current temperature and the previous temperature can be obtained as follows: Where A is the convective heat transfer contact area, and A = 2πrl, T is the ambient temperature, c is the specific heat capacity of the pipe material, and d t The time interval is 10 seconds, m is the mass of the pipe per unit length, and m = 2πrlρ;

[0030] In step five above, the background calculation service module 5 analyzes and organizes historical data collected from temperature measuring points arranged in the on-site drainage pipeline. It uses the two-point method and least squares method to fit the temperature drop trend of some drainage valves. Based on the temperature relationship model between the current moment and the previous moment obtained in step four, a data-driven temperature drop model is established. Then, the temperature drop model after the drainage valves is numerically expressed and displayed, deriving the unit impulse response expression and the normalized expression of the transfer function. The names of the drainage valves are: the pneumatic drainage valve after the check valve of the fourth pump to A small turbine, the main water discharge valve after the outlet electric valve of A steam pump, the pneumatic water supply valve of the main steam pipe, and the check valve at the outlet of B steam pump. The normalized expression for the transfer function of the pneumatic valve for draining water from the outlet electric valve to the unpressurized drain valve is G(s) = 0.0361 / (s+0.001805); the normalized expression for the transfer function of the main drain valve after the outlet electric valve of pump A is G(s) = 0.0195 / (s+0.000972); the normalized expression for the transfer function of the pneumatic valve for water supply in the main steam pipe is G(s) = 0.00596 / (s+0.000297); and the normalized expression for the transfer function of the transfer function from the outlet electric valve to the unpressurized drain valve is G(s) = 0.00978 / (s+0.000489).

[0031] In step six above, a finite state machine model is introduced through the background calculation service module 5, and the valve state is determined by combining the unit impulse response expression and the normalized expression of the transfer function obtained in step five. The valve state is divided into closed state, open state, fully open state, intermediate state, and closed state. When the steam trap is 100% closed, the opening degree is 0, there is no steam leakage, and steam condensation stops, it is determined to be in the closed state. At this time, the unit is operating normally under a certain load. The temperature value of the measuring point located after the steam trap maintains a trend of small fluctuation and a relatively small temperature value over a period of time. That is, the rate of change of the temperature value over a period of time is relatively small. When the rate remains at or below a small constant value, and the temperature reading is close to the ambient temperature, steam leakage may occur, causing abnormal temperature readings at the measuring point, such as a temperature rise or a sustained high value. In this case, the valve needs to be closed. When the steam trap gradually opens, increasing the flow rate and thus the steam is in a positive open state, the temperature at the measuring point downstream of the steam trap will show a continuously increasing trend over a period of time, gradually changing from a lower temperature to a higher temperature, but never reaching the steam temperature. That is, the rate of temperature change remains at or above a constant value for a period of time. The values ​​show a positive correlation, with the temperature reading greater than the initial value. When the steam trap is 100% open (opening degree 1), drainage is normal, and the drainage volume reaches its maximum, it is determined to be in a fully open state. At this time, the unit operates normally under a certain load. The temperature value at the measuring point after the steam trap maintains a relatively large trend change with a small fluctuation range over a period of time, that is, the rate of change of the temperature value remains at or less than a small constant value over a period of time, and the temperature reading is close to the steam temperature value. When the steam trap is between closed and open, and the opening degree reaches a certain value and remains so, drainage is normal, which is determined to be an intermediate state. At this time, the temperature value at the measuring point after the steam trap shows a relatively large trend change with a small fluctuation range over a period of time. The temperature changes within a certain time period, with a relatively small fluctuation and a relatively low reading. That is, the rate of change of the temperature value remains at or below a small constant value over a certain period of time, and the temperature reading is between the ambient temperature and the steam temperature. When the steam trap is gradually closed and the opening degree gradually decreases, the amount of condensate passing through decreases, which is determined to be the positive closed state. At this time, the temperature value at the measuring point after the steam trap shows a continuous decreasing process over a certain period of time, gradually changing from a higher temperature to a lower temperature, but never reaching the ambient temperature. That is, the rate of change of the temperature value over a certain period of time is maintained at or below a constant value and shows a negative correlation, and the temperature reading is lower than the initial value.

[0032] Based on the above, the advantages of this invention are as follows: This invention collects temperature data of the downstream pipeline through the steam trap detection module 2, and then calculates the natural convection heat transfer relationship between the insulation layer and the surrounding air, the heat conduction relationship between the insulation layer, the inner wall and the outer wall of the pipeline, and the forced convection heat transfer relationship of the fluid inside the pipeline based on the data. Then, it establishes a model of the relationship between the current temperature and the previous temperature, and then uses the two-point method and the least squares method to fit the trend of the temperature drop change after the steam trap. Based on the model of the temperature relationship between the current temperature and the previous temperature, a data-driven temperature drop model is established, and the state of the steam trap is judged and managed according to the model, which improves the convenience of valve state judgment and management and extends the service life of the steam trap.

[0033] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the invention can be implemented in other specific forms without departing from its spirit or essential characteristics. Therefore, the embodiments should be considered in all respects as exemplary and non-limiting, and the scope of the invention is defined by the appended claims rather than the foregoing description. Thus, all variations falling within the meaning and scope of equivalents of the claims are intended to be included within the present invention. No reference numerals in the claims should be construed as limiting the scope of the claims.

Claims

1. A method for online monitoring of the status of a steam trap, comprising the following steps: Step 1: Data acquisition of steam traps; Step 2: Data transmission; Step 3: Pipeline heat exchange analysis; Step 4: Temperature relationship analysis; Step 5: Cooling model establishment; Step 6: Valve status determination; Its features are: In step one above, the temperature of the outer wall of the pipe is detected and collected by the steam trap detection module (2). Ambient air temperature and the temperature of the fluid inside the pipe Subsequently, the steam trap detection module (2) collects the temperature of the outer wall of the pipe. Ambient air temperature and the temperature of the fluid inside the pipe The data is transmitted to the intelligent front-end module (3) for display. In step two above, the temperature of the outer wall of the pipe is collected through the data acquisition interface module (4). Ambient air temperature and the temperature of the fluid inside the pipe Transmitted to the backend computing service module (5); In step three above, the background calculation service module (5) receives the temperature of the outer wall of the pipe. Ambient air temperature and the temperature of the fluid inside the pipe Then, the natural convection heat transfer relationship between the insulation layer and the surrounding air was analyzed, followed by the heat conduction relationship between the insulation layer, the inner wall and the outer wall of the pipe, and then the forced convection heat transfer relationship of the fluid inside the pipe was analyzed. In step four above, the background calculation service module (5) combines the natural convection heat transfer relationship between the insulation layer and the surrounding air, the heat conduction relationship between the insulation layer, the inner wall and the outer wall of the pipe and the forced convection heat transfer relationship of the fluid inside the pipe analyzed in step three to establish a model of the temperature relationship between the current moment and the previous moment. In step five above, the background calculation service module (5) analyzes and organizes the historical data collected by the temperature measurement points arranged in the field drainage pipe, fits the cooling process change trend of the drainage valve using the two-point method and the least squares method, establishes a data-driven cooling model based on the temperature relationship model between the current moment and the previous moment obtained in step four, and then expresses the cooling model after the drainage valve numerically to obtain the normalized expression of the transfer function. In step six above, the finite state machine model is introduced through the background calculation service module (5) and the normalized expression of the transfer function obtained in step five is used to determine the valve state. In step six, the valve status is categorized into closed, open, fully open, intermediate, and closed states. When the steam trap is 100% closed (opening degree 0), with no steam leakage, and steam condensation stops, it is considered to be in the closed state. At this time, the unit operates normally under a certain load. The temperature value at the measuring point downstream of the steam trap maintains a relatively small fluctuation over a period of time, meaning the rate of temperature change remains at or below a small constant value, and the temperature reading is close to the ambient temperature. Under these conditions, steam leakage may occur, causing abnormal temperature readings at the measuring point. To prevent the steam trap from rising or maintaining a large value, the valve needs to be closed. When the steam trap gradually opens and the opening increases, the amount of water passing through increases, indicating a positive open state. At this time, the temperature value at the measuring point after the steam trap shows a continuous increasing process over a period of time, gradually changing from a lower temperature to a higher temperature, but never reaching the steam temperature. That is, the rate of change of the temperature value is maintained or greater than a constant value and shows a positive correlation over a period of time, and the temperature reading is greater than the initial value. When the steam trap is 100% open, with an opening of 1, the drainage is normal, and the drainage volume reaches the maximum limit, indicating a fully open state. When the unit is operating normally under a certain load, the temperature value at the measuring point after the steam trap maintains a relatively large trend with small fluctuations over a period of time. That is, the rate of temperature change remains at or below a small constant value over a period of time, and the temperature reading is close to the steam temperature. When the steam trap is between closed and open, and the opening reaches a certain value and is maintained, drainage is normal, which is determined to be the intermediate state. At this time, the temperature value at the measuring point after the steam trap maintains a relatively small trend with small fluctuations over a period of time. That is, the rate of temperature change remains at or below a small constant value over a period of time, and the temperature reading is between the ambient temperature and the steam temperature. When the steam trap gradually closes and the opening gradually decreases, the amount of drainage decreases, which is determined to be the positive closed state. The temperature value at the measuring point located after the steam trap shows a continuous decreasing process over a period of time, gradually changing from a higher temperature to a lower temperature, but never reaching the ambient temperature. That is, the rate of change of the temperature value remains at or below a constant value over a period of time and shows a negative correlation, with the temperature reading being lower than the initial value.

2. The method for online monitoring of the status of a steam trap according to claim 1, characterized in that: In step five, the names of the drain valves are as follows: drain pneumatic valve after the check valve of the fourth pump to A small turbine, main drain valve after the outlet electric valve of A steam pump, main steam main drain pneumatic valve, and drain valve from the outlet check valve of B steam pump to the outlet electric valve to the unpressurized drain valve. The normalized expression of the transfer function of the drain pneumatic valve after the check valve of the fourth pump to A small turbine is G(s) = 0.0361 / (s + 0.001805); the drain valve after the outlet electric valve of A steam pump... The normalized expression for the transfer function is G(s) = 0.0195 / (s + 0.000972); the normalized expression for the transfer function of the main steam pipe drain pneumatic valve is G(s) = 0.00596 / (s + 0.000297); the normalized expression for the transfer function of the section from the outlet check valve of pump B to the outlet electric valve to the unpressurized drain valve is G(s) = 0.00978 / (s + 0.000489).

3. A system for implementing the online monitoring method for the status of a steam trap as described in claim 1, characterized in that: It includes a steam trap management module (1), a steam trap detection module (2), an intelligent front-end module (3), a data acquisition interface module (4), and a background computing service module (5). The steam trap management module (1) controls and connects to the steam trap detection module (2), and the steam trap detection module (2) controls and connects to the intelligent front-end module (3). The intelligent front-end module (3) controls and connects to the data acquisition interface module (4), and the data acquisition interface module (4) controls and connects to the background computing service module (5).

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