Emergency stop control method for hydrogen refueling station with pressure switch

Abstract

The invention discloses a sudden stop control method for a hydrogen refueling station with pressure switches, which comprises the following steps: mounting the pressure switches at positions, close to a pressure source, of a container and a pipeline so as to accurately obtain 4-20MA signals of the container and 4-20MA signals of the pipeline, and mounting a plurality of temperature sensors and flow sensors; the two signals are guided into an ESD analog quantity input module, the analog quantity input module carries out weighted average on the two signals through program configuration, a result is transmitted to an ESD main controller, and when it is judged that the pressure corresponding to at least one of the two signals exceeds a preset range, temperature data and flow data are combined at the same time, and the ESD main controller is started. And when the comprehensive index exceeds a threshold value, a corresponding sudden stop protection action is triggered. Container and pipeline pressure signals are also merged into the ESD, and sudden stop is triggered when pressure change of normal operation and sudden drop pressure during leakage are deviated, so that two sudden stop conditions that the pressure signals and leakage detection logic are parallel are adopted.

Description

Technical Field

[0001] This invention relates to the field of pressure detection technology, and specifically to an emergency stop control method for a hydrogen refueling station equipped with a pressure switch. Background Technology

[0002] Currently, hydrogen refueling stations are equipped with three control systems: the Basic Process Control System (BPCS), the Emergency Disconnection System (ESD), and the Combustible and Toxic Gas Detection System (GDS). The applicant notes that in actual station operations, these three systems are typically configured independently. The independently configured ESD communicates with the BPCS via a serial communication interface.

[0003] The hydrogen refueling station is equipped with hydrogen detectors. An alarm should be triggered when the hydrogen content (by volume) in the air reaches 0.4%, the BPCS system interlock should be activated at 1%, and the ESD should be activated at 1.6%. Leakage alarm devices include on-site detector alarms and control panel alarms in the control room. When the on-site detector detects a gas leak and reaches the alarm threshold, an audible and visual alarm should be issued, and the alarm signal should be simultaneously transmitted to the control panel in the control room. When a leak occurs on-site and the concentration exceeds the gas main unit's alarm limit, the hydrogen main unit will alarm and send a signal to the logic PLC. The alarm will automatically clear when the concentration drops below the limit. When the concentration exceeds the gas main unit's alarm set value, the hydrogen main unit will alarm and send a signal to the safety PLC interlocking ESD, executing a station-wide emergency stop. The system cannot be started until the alarm is cleared and a manual reset command is received.

[0004] The current emergency stop mechanism only operates when a leak is detected, which presents a safety vulnerability. If the detection instruments malfunction, it could lead to an accident. Summary of the Invention

[0005] To address the shortcomings of the prior art, this invention proposes an emergency stop control method for a hydrogen refueling station equipped with a pressure switch.

[0006] To achieve the above-mentioned technical effects, the present invention adopts the following solution: An emergency stop control method for a hydrogen refueling station equipped with a pressure switch includes the following steps: S1: Install pressure switches on the containers and pipelines of the existing hydrogen refueling station near the pressure source to obtain the 4-20mA signal from the containers and the pipelines, and install multiple temperature sensors and flow sensors. S2: The above two signals are imported into the analog input module of the ESD. The analog input module performs a weighted average of the above two signals through program configuration and transmits the result to the ESD main controller. The weighted average adopts an adaptive weighted average algorithm, which dynamically adjusts the weights according to pressure changes. S3: The ESD main controller processes and judges the above two signals. When it is found that the pressure corresponding to at least one of the above two signals exceeds the preset range, it combines temperature data and flow data, uses Kalman filtering to perform data fusion, and triggers the corresponding emergency stop protection action when the comprehensive index exceeds the threshold. The pressure switch includes an explosion-proof housing, an external bracket disposed within the explosion-proof housing, and a pressure switch body housed within the external bracket. The pressure switch body is connected to an external connecting pipe. The external bracket includes: A top cover assembly, the top cover assembly including a top cover body and top cover ears located at both ends of the top cover body, the top cover ears located at both ends simultaneously clamping an annular top plate; A base support assembly, the base support assembly including a base support body and an elastic sheet and a bent sheet integrally formed with the base support body; The receiving assembly includes an annular top plate abutting against a top cover ear, the annular top plate having a top plate positioning hole, and the pressure switch body partially internally connected to the top plate positioning hole; the receiving assembly also includes an insert plate fixedly connected to the annular top plate; the receiving assembly also includes a limiting plate, the insert plate being internally connected to and passing through the limiting plate located on the same side, the bent piece abutting against the limiting plate located on the same side, and the limiting plate abutting against the pressure switch body; The top cover assembly, bottom support assembly, and receiving assembly together form a receiving cavity, and the pressure switch body is located inside the receiving cavity.

[0007] In a preferred embodiment, the pressure switch installed on the container and pipeline is electrically connected to the analog input module via a cable.

[0008] In a preferred embodiment, the limiting plate has a limiting plate body and limiting plate extensions located on both sides of the limiting plate body.

[0009] In a preferred embodiment, the bottom of the limiting plate has a first groove, and the bent piece abuts against the first groove of the limiting plate located on the same side.

[0010] In a preferred embodiment, the limiting plate is further provided with a limiting plate reinforcing plate, which is fixedly connected to the limiting plate body.

[0011] Compared with existing technologies, the beneficial effects are: This invention has a simple structure and is easy to use. It also incorporates the pressure signals of containers and pipelines into ESD. When there is a deviation between the pressure changes during normal operation and the sudden drop in pressure during leakage, an emergency stop is triggered. This provides two emergency stop conditions in parallel: one for pressure signals and one for leakage detection logic. This reduces safety risks and improves the reliability of the system's emergency stop. Attached Figure Description

[0012] Figure 1 This is a schematic diagram of the control relationship of the present invention.

[0013] Figure 2 This is a simplified control logic diagram of the present invention.

[0014] Figure 3 This is a schematic diagram of the pressure switch structure in this invention.

[0015] Figure 4 This is a schematic diagram of the pressure switch in this invention from another perspective.

[0016] Figure 5 This is a side view of the pressure switch in this invention.

[0017] Figure 6 It is along Figure 5 A schematic diagram of the cross-sectional structure along the AA direction. Figure 7 This is a frontal view of the pressure switch in this invention.

[0018] Figure 8 This is a three-dimensional structural diagram of the top cover assembly and bottom support assembly of the pressure switch in this invention from one perspective.

[0019] Figure 9 This is a three-dimensional structural diagram of the top cover assembly and bottom support assembly of the pressure switch in this invention from another perspective.

[0020] Figure 10 This is a three-dimensional structural diagram of the housing component of the pressure switch in this invention.

[0021] Figure 11 This is a three-dimensional structural diagram of the housing component of the pressure switch in this invention.

[0022] Reference numerals: 10. Top cover assembly; 11. Top cover body; 12. Top cover ear; 20. Base support assembly; 21. Base support body; 22. Elastic sheet; 23. Bending sheet; 30. Receiving assembly; 31. Annular top plate; 32. Top plate positioning hole; 33. Insert plate; 34. Limiting plate; 35. Limiting plate body; 36. Limiting plate extension; 37. Limiting plate first groove; 38. Limiting plate reinforcing plate; 381. Reinforcing plate step; 39. Limiting plate second groove; 40. Outer pipe; 50. Pressure switch body; 51. Receiving cavity. Detailed Implementation

[0023] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments.

[0024] An emergency stop control method for a hydrogen refueling station equipped with a pressure switch includes the following steps: S1: Install pressure switches on the containers and pipelines of the existing hydrogen refueling station near the pressure source to obtain the 4-20mA signal from the containers and the pipelines, and install multiple temperature sensors and flow sensors. S2: The above two signals are imported into the analog input module of the ESD. The analog input module performs a weighted average of the above two signals through program configuration and transmits the result to the ESD main controller. The weighted average adopts an adaptive weighted average algorithm, which dynamically adjusts the weights according to pressure changes. S3: The ESD main controller processes and judges the above two signals. When it is found that the pressure corresponding to at least one of the above two signals exceeds the preset range, it combines the temperature data and flow data and uses Kalman filtering to perform data fusion to obtain the optimal estimated value of the system pressure and its rate of change. When the comprehensive index exceeds the threshold, the corresponding emergency stop protection action is triggered.

[0025] The aforementioned pressure switch is installed near the pressure source on the container and pipeline to accurately acquire the 4-20mA signal (pressure signal). The 4-20mA signal is fed into the ESD's analog input module via a connecting cable to ensure reliable and stable connection. The ESD processes and judges the received 4-20mA signal (pressure signal). When the pressure exceeds a certain range, it triggers corresponding protective actions. The range of the 4-20mA signal (pressure signal) depends on the specific application scenario and system requirements, and can generally be set within the pressure switch's range. Deviations between normal operating pressure changes and sudden pressure drops during leakage trigger an emergency stop. This dual emergency stop condition—one for the pressure signal and one for the leakage detection logic—reduces safety risks.

[0026] In traditional weighted averaging methods, the weights of each sensor signal are fixed values ​​set in advance. The core of the adaptive weighted averaging method used in this invention lies in the fact that the weight coefficients are no longer fixed, but dynamically adjusted according to the real-time characteristics of the sensor signals and the system state. This achieves more intelligent and reliable data fusion and decision-making. The specific implementation of the adaptive weighted averaging algorithm is as follows: The weighting coefficients W1 and W2 assigned to the container pressure signal and the pipeline pressure signal are not fixed, but are dynamically calculated based on the real-time characteristics of the signals.

[0027] Specifically, the weight calculation mainly considers the following factors: a) Signal change rate: The system calculates the absolute value ΔP of the change in each pressure signal per unit time in real time. When the ΔP of a certain signal exceeds a preset threshold, its weight will increase significantly, so that the weighted average can reflect the sudden change trend of the signal more quickly, thereby accelerating the emergency stop triggering when a leak occurs.

[0028] b) Signal stability: The system calculates the variance σ of each pressure signal within the sliding time window. ² The larger the variance, the more drastic the signal fluctuation, the lower its reliability, and the corresponding weight will be reduced. This effectively suppresses misjudgments caused by instantaneous interference or slow drift of the sensor.

[0029] The final overall weights are normalized to ensure W1 + W2 = 1. Then, the ESD master controller calculates the current system pressure value using the formula P_avg = W1 * ΔP1 + W2 * ΔP2. (ΔP1 is the absolute change in the pressure signal of the container per unit time, and ΔP2 is the absolute change in the pressure signal of the pipeline per unit time.) Through this adaptive mechanism, the system can smooth pressure readings under normal conditions, quickly focus on abnormal signals under abnormal conditions, and automatically reduce the impact of some sensor performance degradation, thereby comprehensively improving the intelligence and reliability of control.

[0030] The Kalman filter described is an optimal recursive data processing algorithm that fuses noisy sensor data through two steps: prediction and update, to obtain the optimal estimate of the system state. In this invention, the system state is the quantity we are most concerned with but cannot directly and accurately measure—the "true pressure" of the hydrogen refueling station system and its changing trend.

[0031] The Kalman filter algorithm includes the following steps: a) State prediction: Predict the system state at the current moment based on the system state at the previous moment, wherein the system state includes at least the pressure value and the pressure change rate; b) Observation update: Using the observations from multiple sensors collected at the current moment, the predicted state is corrected by calculating the Kalman gain to obtain the optimal estimate of the system state at the current moment; c) The ESD master controller makes a judgment based on the pressure value and / or pressure change rate in the optimal estimate to trigger a protection action.

[0032] Deeply integrating temperature, flow, and pressure signals at the model level can better distinguish between normal operation (such as a slight decrease in pressure due to a drop in temperature) and abnormal leakage, significantly reducing the false alarm rate.

[0033] The pressure switch includes an explosion-proof housing, an external bracket disposed within the explosion-proof housing, and a pressure switch body 50 (for judging the pressure of gases such as hydrogen) housed within the external bracket. The pressure switch body 50 is connected to an external pipe 40 (for allowing the introduction of gases such as hydrogen). The external bracket includes: Top cover assembly 10, the top cover assembly 10 includes a top cover body 11 and top cover ears 12 located at both ends of the top cover body 11, the top cover ears 12 located on both sides simultaneously clamping an annular top plate 31; The base support assembly 20 includes a base support body 21 and an elastic sheet 22 and a bent sheet 23 integrally formed with the base support body 21. The receiving component 30 includes an annular top plate 31, abutting against the top cover ear 12. The annular top plate 31 has a top plate positioning hole 32, and the top of the pressure switch body 50 is partially inserted into the top plate positioning hole 32, so that the pressure switch body 50 remains relatively fixed relative to the annular top plate 31, which helps to improve the overall stability of the pressure switch body 50. In addition, considering that the horizontal length of different types of pressure switch bodies 50 may vary, the horizontal length of the top plate positioning hole 32 in this application is designed to be as long as possible (while ensuring the overall rigidity of the annular top plate 31), so as to adapt to multiple pressure switch bodies 50, which helps to expand the scope of application and improve compatibility. The receiving component 30 further includes a insert plate 33, the top of which is fixedly connected to the lower surface of the annular top plate 31. Preferably, there are two insert plates 33, which are in the form of thin sheets. The receiving component 30 further includes a limiting plate 34, preferably two limiting plates 34. The limiting plate 34 is in the form of a thin sheet. The insert plate 33 is internally connected to and passes through the limiting plate 34 located on the same side. The inner surface of the bent piece 23 abuts against the outer surface of the limiting plate 34 located on the same side. The inner surface of the limiting plate 34 abuts against the outer surface of the pressure switch body 50, so that the pressure switch body 50 remains relatively fixed relative to the limiting plate 34, which helps to improve the overall stability of the pressure switch body 50. The top cover assembly 10, the bottom support assembly 20, and the receiving assembly 30 together form a (semi-open) receiving cavity 51, and the pressure switch body 50 is located inside the receiving cavity 51.

[0034] In a preferred embodiment, the pressure switch installed on the container and pipeline is electrically connected to the analog input module via a cable.

[0035] In a preferred embodiment, the limiting plate 34 is provided with a limiting plate body 35 and limiting plate extensions 36 located on both sides of the limiting plate body 35. The horizontal length of the limiting plate extensions 36 is designed to be as long as possible, thereby limiting multiple pressure switch bodies 50, which helps to expand the scope of application and improve compatibility.

[0036] In a preferred embodiment, the bottom of the limiting plate 34 has a first groove 37, and the inner surface of the bent piece 23 abuts against the first groove 37 of the limiting plate 34 located on the same side.

[0037] In a preferred embodiment, the limiting plate 34 is further provided with a limiting plate reinforcing plate 38, which is fixedly connected to the limiting plate body 35 and is mainly arranged along the longitudinal direction, in order to enhance the load-bearing capacity of the limiting plate 34 in the longitudinal direction.

[0038] In a preferred embodiment, the limiting plate body 35 has a limiting plate second groove 39, and the limiting plate reinforcing plate 38 is provided with a reinforcing plate step portion 381. The reinforcing plate step portion 381 is located in the limiting plate second groove 39, and the reinforcing plate step portion 381 can be used to support the limiting plate body 35.

[0039] It should be noted that although this application intends to adapt to multiple pressure switch bodies 50 at the same time, there are many different types of commercially available pressure switch bodies 50. This application mainly aims to adapt to the thin-film pressure switch body 50, and does not intend to adapt to all commercially available pressure switch bodies 50.

[0040] In this application, the "BPCS" that may be involved in various embodiments is defined as: Basic Process Control System. It collects and records the operating status and parameters of each major process equipment in real time, and automatically controls the safe operation of the equipment based on these process parameters; it achieves centralized monitoring and control of the station, and alarm signals and their processing results should be recorded in the system database.

[0041] In this application, the term "ESD" that may be involved in various embodiments is defined as: Emergency Shutdown System. It provides personal protection and equipment protection. In the event of an accident, it can provide protection by stopping the vehicle in an emergency and closing the emergency shut-off valve.

[0042] In the various embodiments of this application, "GDS" may be involved, which we define as: a combustible and toxic gas detection system.

[0043] In the various embodiments of this application, the term "PLC" may be used to define a programmable logic controller or a programmable logic control process.

[0044] In the description of this invention, it should be understood that the terms "upper," "lower," "top," "bottom," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship commonly used when the product of this invention is in use, or the orientation or positional relationship commonly understood by those skilled in the art. They are only used to facilitate the description of this invention and to simplify the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0045] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this invention, "a plurality of" means two or more, unless otherwise explicitly specified.

[0046] Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without inventive effort are within the scope of protection of this invention.

Claims

1. An emergency stop control method for a hydrogen refueling station equipped with a pressure switch, characterized in that, Includes the following steps: S1: Install pressure switches on the containers and pipelines of the existing hydrogen refueling station near the pressure source to obtain the 4-20mA signal from the containers and the pipelines, and install multiple temperature sensors and flow sensors. S2: The above two signals are imported into the analog input module of the ESD. The analog input module performs a weighted average of the above two signals through program configuration and transmits the result to the ESD main controller. The weighted average adopts an adaptive weighted average algorithm, which dynamically adjusts the weights according to pressure changes. S3: The ESD main controller processes and judges the above two signals. When it is found that the pressure corresponding to at least one of the above two signals exceeds the preset range, it combines temperature data and flow data, uses Kalman filtering to perform data fusion, and triggers the corresponding emergency stop protection action when the comprehensive index exceeds the threshold. The pressure switch includes an explosion-proof housing, an external bracket disposed within the explosion-proof housing, and a pressure switch body (50) housed within the external bracket. The pressure switch body (50) is connected to an external connector (40). The external bracket includes: Top cover assembly (10), the top cover assembly (10) includes a top cover body (11) and top cover ears (12) located at both ends of the top cover body (11), the top cover ears (12) located on both sides simultaneously clamp the annular top plate (31). The base assembly (20) includes a base body (21) and an elastic sheet (22) and a bent sheet (23) integrally formed with the base body (21). The receiving assembly (30) includes an annular top plate (31) that abuts against a top cover ear (12). The annular top plate (31) has a top plate positioning hole (32), and the pressure switch body (50) is partially internally connected to the top plate positioning hole (32). The receiving assembly (30) also includes a plug plate (33) that is fixedly connected to the annular top plate (31). The receiving assembly (30) also includes a limiting plate (34), in which the plug plate (33) is internally connected to and passes through the limiting plate (34) located on the same side. The bent piece (23) abuts against the limiting plate (34) located on the same side, and the limiting plate (34) abuts against the pressure switch body (50). The top cover assembly (10), the bottom support assembly (20), and the receiving assembly (30) together form a receiving cavity (51), and the pressure switch body (50) is located inside the receiving cavity (51).

2. The emergency stop control method for a hydrogen refueling station equipped with a pressure switch as described in claim 1, characterized in that, Pressure switches installed on containers and pipelines are electrically connected to analog input modules via cables.

3. The emergency stop control method for a hydrogen refueling station equipped with a pressure switch as described in claim 1, characterized in that, The limiting plate (34) is provided with a limiting plate body (35) and limiting plate extensions (36) located on both sides of the limiting plate body (35).

4. The emergency stop control method for a hydrogen refueling station equipped with a pressure switch as described in claim 1, characterized in that, The bottom of the limiting plate (34) has a first groove (37) of the limiting plate, and the bent piece (23) abuts against the first groove (37) of the limiting plate (34) located on the same side.

5. The emergency stop control method for a hydrogen refueling station equipped with a pressure switch as described in claim 1, characterized in that, The limiting plate (34) is also provided with a limiting plate reinforcing plate (38), which is fixedly connected to the limiting plate body (35).

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