Failure risk assessment method and device for pressure regulator of gas station

Abstract

The invention provides a gas station pressure regulator failure risk assessment method and device. The method comprises the following steps: determining components forming the voltage regulator according to the model of the voltage regulator; determining a failure mode of each component of the voltage regulator and a corresponding failure influence, a failure reason and a risk value thereof, and establishing an FMEA table on the basis of the failure mode and the failure influence, the failure reason and the risk value; establishing a voltage regulator failure fault tree model based on an FMEA table; and based on the FMEA table and the voltage regulator failure fault tree model, performing voltage regulator failure risk assessment. The FMEA and the FTA are combined, so that more comprehensive, systematic and accurate fault analysis can be realized, the reliability, the safety and the performance of the system can be improved, the fault risk can be reduced, and the overall benefit of the system can be improved.

Description

Technical Field

[0001] The present invention belongs to the technical field of failure risk assessment, and in particular relates to a method and device for assessing the failure risk of a gas station pressure regulator. Background Art

[0002] With the adjustment of energy structure and the vigorous implementation of the "coal to gas" policy, high-quality, efficient, green and clean natural gas energy has gradually occupied an important position in the energy structure. The increase in urbanization rate has led to a continuous increase in the gas usage rate of residents, and the application of urban gas systems has become more and more extensive.

[0003] Failure Mode and Effect Analysis (FMEA) and Fault Tree Analysis (FTA) are commonly used risk assessment methods and are widely used in the engineering field to identify and evaluate the possibility of system failures and their potential consequences. FMEA is a systematic method used to identify potential system failure modes, determine the extent of the impact of these failure modes on system functions, and provide a basis for priority handling of failures. Through FMEA analysis, we can gain an in-depth understanding of the various failure modes that may occur in system equipment, and can also evaluate the probability, severity and controllability of these failure modes to determine which failure modes may have a significant impact on system safety. Based on FMEA, Fault Tree Analysis (FTA) further explores the root causes of system failures. FTA represents various basic events that may cause system failures in a tree structure, and through the analysis of logical relationships, it reveals the causal relationship between failure events.

[0004] The pressure regulator is one of the important equipment in the city gas system and is widely used in various gas stations. How to evaluate the safety and reliability of the pressure regulator in the gas station has attracted increasing attention. To this end, the present invention proposes a method and device for evaluating the failure risk of the pressure regulator in the gas station based on FMEA and FTA. Summary of the invention

[0005] In order to solve the above problems existing in the prior art, the present invention provides a method and device for assessing the failure risk of a gas station pressure regulator.

[0006] In order to achieve the above object, the present invention adopts the following technical solutions.

[0007] In a first aspect, the present invention provides a method for assessing the failure risk of a gas station pressure regulator, comprising the following steps:

[0008] Determine the components that make up the voltage regulator based on the model of the voltage regulator;

[0009] Determine the failure modes of each component of the voltage regulator and their corresponding failure effects, failure causes and risk values, and establish an FMEA table based on this;

[0010] Establish the voltage regulator failure fault tree model based on the FMEA table;

[0011] Based on the FMEA table and the voltage regulator failure fault tree model, the voltage regulator failure risk assessment is carried out.

[0012] Furthermore, the components constituting the pressure regulator include: a diaphragm, a spring, a valve stem, a valve core, a valve seat, a signal tube, and an adjusting lever.

[0013] Furthermore, the failure modes of various components of the pressure regulator include: leakage between the diaphragm and the valve seat, rupture and aging of the diaphragm; spring relaxation and spring breakage; valve stem blockage, valve stem wear and breakage; valve core blockage, valve core wear or damage; valve seat medium erosion, valve seat wear or damage; signal tube blockage; and regulating lever breakage.

[0014] Furthermore, the calculation formula of the risk value corresponding to the failure mode of each component of the voltage regulator is:

[0015] RPN=S×O×D

[0016] Wherein, RPN is the risk value of the failure mode, S is the severity of the failure mode, O is the occurrence frequency of the failure mode, and D is the detection capability of the failure mode. The value ranges of S, O, and D are all 1 to 10, and the value range of RPN is 1 to 1000.

[0017] Furthermore, the voltage regulator failure fault tree model includes top-level events, middle-level events, and bottom-level events; among them,

[0018] The top-level event is the voltage regulator failure Z;

[0019] The middle layer events include: membrane failure Z1, spring failure Z2, valve stem failure Z3, valve core failure Z4, valve seat failure Z5, signal tube failure Z6, and adjustment lever failure Z7;

[0020] The underlying events of membrane failure Z1 include membrane rupture and aging Z 11 , Leakage between the diaphragm and the valve seat Z 12 , the underlying event of spring failure Z2 includes spring relaxation Z 21 , spring breakage Z 22 , the underlying events of valve stem failure Z3 include valve stem blockage Z 31 , Valve stem wear and fracture Z 31 The underlying events of valve core failure Z4 include valve core blockage Z 41 , Valve core wear Z 42 The underlying events of valve seat failure Z5 include valve seat medium erosion Z 51 , Valve seat wear Z 52 The underlying events of signal tube failure Z6 include signal tube blockage Z 61The underlying event of the adjustment lever failure Z7 includes the adjustment lever breakage Z 71 .

[0021] Furthermore, the logical relationship between the events at each level of the voltage regulator failure fault tree model is as follows:

[0022] Z=Z1+Z2+......+Z7

[0023] Z i =Z i1 +Z i2 , Z6=Z 61 , Z7=Z 71

[0024] In the formula, “+” represents logical OR, i=1,2,......,5.

[0025] Furthermore, the probability of regulator failure is:

[0026]

[0027] Where P Z is the probability of regulator failure event Z, P i is the i-th intermediate layer event Z i The probability, P ij is the jth bottom-level event Z of the i-th intermediate-level event ij The probability of N i is the i-th intermediate layer event Z i The number of underlying events, when i=1,2,......,5, N i =2; when i=6,7, N i =1.

[0028] Furthermore, the voltage regulator failure risk assessment includes:

[0029] Calculate the risk value RPN of each failure mode based on S, O, and D;

[0030] determining a failure mode in which the RPN exceeds a first threshold;

[0031] Determine maintenance and correction measures for the voltage regulator based on the failure mode.

[0032] Furthermore, the voltage regulator failure risk assessment includes:

[0033] Calculate the risk value RPN of each failure mode based on S, O, and D;

[0034] determining a failure mode in which RPN exceeds a first threshold and S exceeds a second threshold;

[0035] Determine maintenance and correction measures for the voltage regulator based on the failure mode.

[0036] In a second aspect, the present invention provides a gas station pressure regulator failure risk assessment device, comprising:

[0037] A structure determination module, used for determining components constituting the voltage regulator according to the model of the voltage regulator;

[0038] Table building module, used to determine the failure modes of each component of the voltage regulator and its corresponding failure impact, failure cause and risk value, and build the FMEA table based on this;

[0039] Fault tree building module, used to build the voltage regulator failure fault tree model based on the FMEA table;

[0040] The sensitivity assessment module is used to conduct a failure risk assessment of the voltage regulator based on the FMEA table and the voltage regulator failure fault tree model.

[0041] Compared with the prior art, the present invention has the following beneficial effects.

[0042] The present invention determines the components constituting the voltage regulator according to the model of the voltage regulator, determines the failure mode of each component of the voltage regulator and its corresponding failure impact, failure cause and risk value, and establishes an FMEA table on this basis. Based on the FMEA table and the voltage regulator failure fault tree model, the voltage regulator failure risk assessment is performed, thereby realizing the failure risk assessment of the gas station voltage regulator. By combining FMEA and FTA, the present invention can achieve a more comprehensive, systematic and accurate fault analysis, which helps to improve the reliability, safety and performance of the system, reduce the risk of failure, and thus improve the overall benefit of the system. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] Figure 1 The present invention is a flowchart of a method for assessing the risk of failure of a gas station pressure regulator according to an embodiment of the present invention.

[0044] Figure 2 Schematic diagram of the fault tree model of voltage regulator failure.

[0045] Figure 3 The present invention is a block diagram of a gas station pressure regulator failure risk assessment device according to an embodiment of the present invention. DETAILED DESCRIPTION

[0046] In order to make the purpose, technical solution and advantages of the present invention clearer and more understandable, the present invention is further described below in conjunction with the accompanying drawings and specific implementation methods. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0047] Figure 1 This is a flow chart of a method for assessing the risk of failure of a gas station pressure regulator according to an embodiment of the present invention, comprising the following steps:

[0048] Step 101, determining components constituting the voltage regulator according to the model of the voltage regulator;

[0049] Step 102, determining the failure modes of various components of the voltage regulator and their corresponding failure effects, failure causes and risk values, and establishing a FMEA table based on these;

[0050] Step 103, establishing a voltage regulator failure fault tree model based on the FMEA table;

[0051] Step 104 : Based on the FMEA table and the voltage regulator failure fault tree model, a voltage regulator failure risk assessment is performed.

[0052] In this embodiment, step 101 is mainly used to determine the structure of the voltage regulator. There are many types of voltage regulators, and different voltage regulators are required for different scenarios. The components that constitute the voltage regulator also have certain differences. Therefore, it is necessary to first determine its internal structure according to the model of the voltage regulator. Gas station pressure regulators can be divided into two types: direct-acting and indirect-acting according to different working principles. The direct-acting pressure regulator has a simpler structure and less pressure loss. It is often used in stations that need to continuously supply higher flow rates downstream. Due to its high voltage stabilization accuracy and large adjustment range, the indirect-acting pressure regulator is often used in regional pressure regulating stations or city gate stations with large flow changes and high pressure regulation accuracy requirements.

[0053] In this embodiment, step 102 is mainly used to establish a FMEA table. In this embodiment, the failure mode of each component of the voltage regulator is first determined based on the historical data of the voltage regulator, and the failure cause and failure impact of each failure mode are analyzed to calculate the risk value of the failure mode of each component; then, a FMEA table is established based on the failure mode, failure cause, failure impact and risk value. The FMEA table is shown in Table 1.

[0054] Table 1FMEA table

[0055]

[0056]

[0057] In this embodiment, step 103 is mainly used to establish a voltage regulator failure fault tree model. In this embodiment, a voltage regulator failure fault tree model is established based on the FMEA table. According to Table 1, the various layer events of the fault tree model can be determined. For example, the voltage regulator failure can be used as the top-level event, the failure of each component can be used as the middle-level event, and the failure mode of each component can be used as the bottom-level event to establish a voltage regulator failure fault tree model. Figure 2 shown.

[0058] In this embodiment, step 104 is mainly used to perform a failure risk assessment of the voltage regulator. This embodiment performs a failure risk assessment of the voltage regulator based on FMEA and FTA, and proposes maintenance and improvement measures on this basis. First, according to the size of the failure mode risk value obtained in the above steps, determine which failure modes need to be dealt with first. For example, according to Table 1, the risk values ​​of the failure modes of damaged membrane, broken spring, and worn and broken valve stem are 144, 168, and 126, respectively, which are significantly higher than the risk values ​​of other failure modes. Therefore, these three failure modes should be dealt with first; then, maintenance and improvement measures are proposed for these failure modes, and the corresponding voltage regulator components are maintained or improved to improve the performance of the voltage regulator.

[0059] As an optional embodiment, the components constituting the pressure regulator include: a diaphragm, a spring, a valve stem, a valve core, a valve seat, a signal tube, and an adjusting lever.

[0060] This embodiment provides a specific structure of a pressure regulator. The pressure regulator of this embodiment is a direct-acting pressure regulator. Because not all internal components of a direct-acting pressure regulator have the risk of failure, and the main risk of failure is concentrated in several components, this embodiment only selects a part of the components as the components of the direct-acting pressure regulator, mainly involving: diaphragm, spring, valve stem, valve core, valve seat, signal tube, adjustment lever, etc. Among them, the diaphragm is an elastic component used to convert the sensor signal into force; the spring is usually used to provide a reaction force, and works together with the medium pressure to help the valve core achieve the adjustment function; the valve stem is used to transmit torque and plays a driving role in the valve body; the valve core is a component that directly acts on the flow of the medium, and adjusts the cross-sectional area of ​​the channel according to the signal fed back by the sensor; the valve seat is located in the valve body, providing axial guidance for the movement of the valve core and ensuring the sealing performance between the valve core and the valve seat; the signal tube is used to transmit the outlet pressure; the adjustment lever is used to transmit torque.

[0061] As an optional embodiment, the failure modes of the various components of the pressure regulator include: leakage between the diaphragm and the valve seat, rupture and aging of the diaphragm; spring relaxation and spring breakage; valve stem blockage, valve stem wear and breakage; valve core blockage, valve core wear or damage; valve seat medium erosion, valve seat wear or damage; signal tube blockage; and regulating lever breakage.

[0062] This embodiment provides the failure modes of various components of the pressure regulator. Each component may have at least one failure mode. The failure modes of the membrane include leakage between the membrane and the valve seat, and rupture and aging of the membrane; the cause of the membrane failure may be excessive stress causing the membrane to deform and rupture, or it may be aging of the membrane due to long-term use; the failure of the membrane will cause the failure of the pressure regulator due to the inability to transmit normal signals. The failure modes of the spring include spring relaxation and spring breakage; the cause of the spring failure may be long-term use causing the spring elasticity to decrease, or fatigue and overload causing breakage; the failure of the spring will cause the failure of the pressure regulator due to the inability to transmit the force. The failure modes of the valve stem include valve stem blockage, valve stem wear and breakage; the cause of the valve stem failure may be fouling, or medium erosion, fatigue fracture; the failure of the valve stem will cause the failure of the pressure regulator due to the inability to transmit torque normally. The failure modes of the valve core include valve core blockage, valve core wear or damage; the cause of the valve core failure may be blockage by the medium, or long-term use causing the valve core surface to wear, and solid particles in the medium; the failure of the valve core will cause the failure of the pressure regulator due to the inability to feedback the signal. The failure modes of the valve seat include erosion of the valve seat by the medium, wear or damage to the valve seat; the cause of the valve seat failure may be the erosion of the valve seat by the corrosive medium, or the wear or damage of the valve seat surface caused by the friction between the valve seat and the valve core; the failure of the valve seat will cause the failure of the pressure regulator due to the impact on the sealing. The failure mode of the signal tube includes blockage; the cause of the failure of the signal tube may be scale accumulation and ice blockage; the failure of the signal tube will cause the failure of the pressure regulator due to the failure to sense the signal normally. The failure mode of the adjustment lever includes fracture; the cause of the failure of the adjustment lever may be fatigue fracture; the failure of the adjustment lever will cause the failure of the pressure regulator due to the inability to transmit torque.

[0063] As an optional embodiment, the calculation formula of the risk value corresponding to the failure mode of each component of the voltage regulator is:

[0064] RPN=S×O×D

[0065] Wherein, RPN is the risk value of the failure mode, S is the severity of the failure mode, O is the occurrence frequency of the failure mode, and D is the detection capability of the failure mode. The value ranges of S, O, and D are all 1 to 10, and the value range of RPN is 1 to 1000.

[0066] This embodiment provides a method for calculating the risk value corresponding to the failure mode. The risk value is an indicator parameter used to quantitatively evaluate the severity of the risk, which is usually used in quality management and risk analysis. The risk value is related to three factors: the severity S (Severity), the occurrence frequency O (Occurrence) and the detection capability D (Detection) of the failure mode. By calculating the product of these three factors (factors), a risk value corresponding to the failure mode can be obtained. Usually, the value range of severity S, occurrence frequency O, and detection capability D is 1 to 10, and the value range of RPN is 1 to 1000. The values ​​of S, O and D are generally assessed by an expert group.

[0067] As an optional embodiment, the voltage regulator failure fault tree model includes top-level events, middle-level events and bottom-level events; wherein,

[0068] The top-level event is the voltage regulator failure Z;

[0069] The middle layer events include: membrane failure Z1, spring failure Z2, valve stem failure Z3, valve core failure Z4, valve seat failure Z5, signal tube failure Z6, and adjustment lever failure Z7;

[0070] The underlying events of membrane failure Z1 include membrane rupture and aging Z 11 , Leakage between the diaphragm and the valve seat Z 12 , the underlying event of spring failure Z2 includes spring relaxation Z 21 , spring breakage Z 22 , the underlying events of valve stem failure Z3 include valve stem blockage Z 31 , Valve stem wear and fracture Z 31 The underlying events of valve core failure Z4 include valve core blockage Z 41 , Valve core wear Z 42 The underlying events of valve seat failure Z5 include valve seat medium erosion Z 51 , Valve seat wear Z 52 The underlying events of signal tube failure Z6 include signal tube blockage Z 61 The underlying event of the adjustment lever failure Z7 includes the adjustment lever breakage Z 71 .

[0071] This embodiment provides a specific structure of a voltage regulator failure fault tree model. The fault tree model of this embodiment consists of three levels of events, namely, top-level events, middle-level events, and bottom-level events. Figure 2 As shown in the figure, the top event is the failure of the pressure regulator Z; the middle events include the membrane failure Z1, spring failure Z2, valve stem failure Z3, valve core failure Z4, valve seat failure Z5, signal tube failure Z6 and adjustment lever failure Z7; the bottom events correspond to various failure modes, see Figure 2 .

[0072] As an optional embodiment, the logical relationship between the events at each level of the voltage regulator failure fault tree model is:

[0073] Z=Z1+Z2+......+Z7

[0074] Z i =Z i1 +Z i2 , Z6=Z 61 , Z7=Z 71

[0075] In the formula, “+” represents logical OR, i=1,2,......,5.

[0076] This embodiment provides the logical relationship between the events at each level of the voltage regulator failure fault tree model. In this embodiment, the top-level event voltage regulator failure Z is equal to the logical OR of the seven middle-level events Z1 to Z7; each middle-level event is also equal to the logical OR of its corresponding bottom-level event, such as Figure 2 It is worth noting that the logical relationship of the fault tree model in this embodiment is only a special case (all logical OR), and is not general. In many cases, the logical relationship of the fault tree model is relatively complex, including not only logical OR, but also logical AND and other logical relationships.

[0077] As an optional embodiment, the probability of voltage regulator failure is:

[0078]

[0079] Where P Z is the probability of regulator failure event Z, P i is the i-th intermediate layer event Z i The probability, P ij is the jth bottom-level event Z of the i-th intermediate-level event ij The probability of N i is the i-th intermediate layer event Z i The number of underlying events, when i=1,2,......,5, N i =2; when i=6,7, N i =1.

[0080] This embodiment provides a technical solution for calculating the failure probability of a voltage regulator. In this embodiment, the probability of a voltage regulator failure in the top-level event is equal to the sum of the probabilities of the seven middle-level events, which is equal to the sum of the probabilities of all bottom-level events. It is worth noting that the probability calculation scheme in this embodiment is for Figure 2The fault tree model shown in the figure, that is to say, the above probability calculation formula is only applicable to the case where the logical relationship of each layer event is all logical OR; when the logical relationship is not all logical OR, the probability calculation formula will also change accordingly. For example, if the two bottom events Z of the middle layer event Z1 are 11 , Z 12 The logical relationship is logical AND, then the probability P1 of Z1 is equal to Z 11 , Z 12 The probability P 11 , P 12 The product of P1 = P 11 ×P 12 .

[0081] Based on the probability calculation of each layer of events, the voltage regulator can be evaluated for sensitivity and maintenance measures can be proposed. The sensitivity evaluation is to determine the sensitivity of the fault tree to the change in the probability of occurrence of different basic events. The sensitivity evaluation helps to determine which basic events have the greatest impact on the top-level events, so as to prioritize maintenance measures for these events. Each basic event can be adjusted slightly one by one, and the probability change of the top-level event after adjustment can be calculated. The change in the probability of the top-level event after each adjustment can be recorded and compared to evaluate the sensitivity of the system to each basic event.

[0082] As an optional embodiment, the step of performing a failure risk assessment of a voltage regulator includes:

[0083] Calculate the risk value RPN of each failure mode based on S, O, and D;

[0084] determining a failure mode in which the RPN exceeds a first threshold;

[0085] Determine maintenance and correction measures for the voltage regulator based on the failure mode.

[0086] This embodiment provides a technical solution for evaluating the failure risk of a voltage regulator. First, the risk value of each failure mode is calculated, and then the risk value of each failure mode is compared with the first threshold. The failure mode that exceeds the first threshold is treated as a priority, and the maintenance and improvement measures of the voltage regulator are determined according to the cause of the failure. The first threshold can be set by a fixed threshold method or a relative threshold method. The fixed threshold method is to set a fixed RPN threshold, such as 200. The relative threshold method is to set a maximum RPN value that is equal to the risk value. max Proportional threshold, e.g., 0.2RPN max , its size is not fixed, but changes with RPN max changes with the changes.

[0087] As an optional embodiment, the step of performing a failure risk assessment of a voltage regulator includes:

[0088] Calculate the risk value RPN of each failure mode based on S, O, and D;

[0089] determining a failure mode in which RPN exceeds a first threshold and S exceeds a second threshold;

[0090] Determine maintenance and correction measures for the voltage regulator based on the failure mode.

[0091] This embodiment provides another technical solution for performing failure risk assessment of a voltage regulator. The previous embodiment only determines the priority processing object based on the risk value of the failure mode. This embodiment determines the priority processing object based on the risk value RPN and the severity S of the risk value, and takes the failure mode whose RPN exceeds the first threshold and the failure mode whose S exceeds the second threshold as the priority processing object. This embodiment highlights the importance of severity S, that is, even if the risk value of a certain failure mode is small (does not exceed the first threshold), as long as its severity S is large (exceeds the second threshold), the failure mode can also be taken as a priority processing object.

[0092] The severity S is determined by an expert group. The value of S ranges from 1 to 10. The impact of the specific score is as follows:

[0093] 1-3: The impact is slight and has little impact on product functionality or user experience.

[0094] 4-6: The impact is moderate, which may affect certain product functions or user experience, but does not involve security issues.

[0095] 7-8: The impact is large, significantly affecting product functions or user experience, and may involve security issues.

[0096] 9-10: The impact is extremely large and may lead to serious safety issues or legal consequences, and the product will fail completely.

[0097] Figure 3 This is a schematic diagram of the composition of a gas station pressure regulator failure risk assessment device according to an embodiment of the present invention, the device comprising:

[0098] A structure determination module 11, used to determine the components constituting the voltage regulator according to the model of the voltage regulator;

[0099] The table building module 12 is used to determine the failure modes of various components of the voltage regulator and their corresponding failure effects, failure causes and risk values, and to build a FMEA table based on this;

[0100] A fault tree building module 13 is used to build a voltage regulator failure fault tree model based on the FMEA table;

[0101] The sensitivity assessment module 14 is used to perform a failure risk assessment of the voltage regulator based on the FMEA table and the voltage regulator failure fault tree model.

[0102] The device of this embodiment can be used to perform Figure 1 The technical solution of the method embodiment shown has similar implementation principles and technical effects, which will not be repeated here.

[0103] The above is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily thought of by a person skilled in the art within the technical scope disclosed by the present invention should be included in the protection scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the protection scope of the claims.

Claims

1. A method for assessing the failure risk of a gas station pressure regulator, characterized in that: The following steps are involved: Determine the components that make up the voltage regulator based on the model of the voltage regulator; Determine the failure modes of each component of the voltage regulator and their corresponding failure effects, failure causes and risk values, and establish an FMEA table based on this; Establish the voltage regulator failure fault tree model based on the FMEA table; Based on the FMEA table and the voltage regulator failure fault tree model, the voltage regulator failure risk assessment is carried out.

2. The method for assessing the failure risk of a gas station pressure regulator according to claim 1, characterized in that: The components of the pressure regulator include: diaphragm, spring, valve stem, valve core, valve seat, signal tube, and adjusting lever.

3. The method for assessing the failure risk of a gas station pressure regulator according to claim 2, characterized in that: The failure modes of various components of the pressure regulator include: leakage between the diaphragm and the valve seat, rupture and aging of the diaphragm; spring relaxation and spring breakage; valve stem blockage, valve stem wear and breakage; valve core blockage, valve core wear or damage; valve seat medium erosion, valve seat wear or damage; signal tube blockage; and regulating lever breakage.

4. The method for assessing the failure risk of a gas station pressure regulator according to claim 1, characterized in that: The calculation formula of the risk value corresponding to the failure mode of each component of the voltage regulator is: RPN=S×O×D Wherein, RPN is the risk value of the failure mode, S is the severity of the failure mode, O is the occurrence frequency of the failure mode, and D is the detection capability of the failure mode. The value ranges of S, O, and D are all 1 to 10, and the value range of RPN is 1 to 1000.

5. The method for assessing the failure risk of a gas station pressure regulator according to claim 3, characterized in that: The voltage regulator failure fault tree model includes top-level events, middle-level events, and bottom-level events; among them, The top event is the voltage regulator failure Z; The middle layer events include: membrane failure Z1, spring failure Z2, valve stem failure Z3, valve core failure Z4, valve seat failure Z5, signal tube failure Z6, and adjustment lever failure Z7; The underlying events of membrane failure Z1 include membrane rupture and aging Z 11 , Leakage between the diaphragm and the valve seat Z 12 , the underlying event of spring failure Z2 includes spring relaxation Z 21 , spring break Z 22 , the underlying events of valve stem failure Z3 include valve stem blockage Z 31 , Valve stem wear and fracture Z 31 The underlying events of valve core failure Z4 include valve core blockage Z 41 , Valve core wear Z 42 The underlying events of valve seat failure Z5 include valve seat medium erosion Z 51 , Valve seat wear Z 52 The underlying events of signal tube failure Z6 include signal tube blockage Z 61 The underlying event of the adjustment lever failure Z7 includes the adjustment lever breakage Z 71 .

6. The method for assessing the failure risk of a gas station pressure regulator according to claim 5, characterized in that: The logical relationship between the events at each level of the voltage regulator failure fault tree model is: Z=Z1+Z2+......+Z7 Z i =Z i1 +Z i2 ,Z6=Z 61 ,Z7=Z 71 In the formula, "+" represents logical OR, i=1,2,......,5.

7. The method for assessing the failure risk of a gas station pressure regulator according to claim 6, characterized in that: The probability of a voltage regulator failure is: Where P Z is the probability of regulator failure event Z, P i is the i-th intermediate layer event Z i The probability, P ij is the jth bottom-level event Z of the i-th intermediate-level event ij The probability of N i is the i-th intermediate layer event Z i The number of underlying events, when i=1,2,......,5, N i =2; when i=6,7, N i =1.

8. The method for assessing the failure risk of a gas station pressure regulator according to claim 4, characterized in that: The voltage regulator failure risk assessment includes: Calculate the risk value RPN of each failure mode based on S, O, and D; determining a failure mode in which the RPN exceeds a first threshold; Determine maintenance and correction measures for the voltage regulator based on the failure mode.

9. The method for assessing the failure risk of a gas station pressure regulator according to claim 4, characterized in that: The voltage regulator failure risk assessment includes: Calculate the risk value RPN of each failure mode based on S, O, and D; determining a failure mode in which RPN exceeds a first threshold and S exceeds a second threshold; Determine maintenance and correction measures for the voltage regulator based on the failure mode.

10. A gas station pressure regulator failure risk assessment device, characterized in that: include: A structure determination module, used for determining components constituting the voltage regulator according to the model of the voltage regulator; Table building module, used to determine the failure modes of each component of the voltage regulator and its corresponding failure impact, failure cause and risk value, and build the FMEA table based on this; Fault tree building module, used to build the voltage regulator failure fault tree model based on the FMEA table; The sensitivity assessment module is used to conduct a failure risk assessment of the voltage regulator based on the FMEA table and the voltage regulator failure fault tree model.

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