Ultralow-temperature valve control system and method

Abstract

The invention discloses an ultralow-temperature valve control system and method, and relates to the technical field of ultralow-temperature valves. The system comprises a detection unit, a processing unit, a valve controller, a main valve, an auxiliary valve and a valve element pressure module, the detection unit comprises a temperature module, a pipeline pressure module, an ultrasonic module and a flow guide module, and communication is established between a port of the ultrasonic module and a port of the processing unit; the output end of the temperature module and the output end of the pipeline pressure module are connected with the input end of the processing unit, and the output end of the processing unit is connected with the input end of the flow guiding module. The influence of multiphase flow on the flow control precision is avoided, the self-checking period is calculated through valve operation data, the valve controller drives the main valve and the auxiliary valve to conduct self-checking alternately, and the reliability of the valves is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of ultra-low temperature valves, and in particular to an ultra-low temperature valve control system and method. Background Art

[0002] Ultra-low temperature valves are valves that can work normally in extremely low temperature environments. Usually, their working temperature can be as low as minus 196℃ or even minus 253℃, minus 196℃ is the temperature of liquid nitrogen, and minus 253℃ is the temperature of liquid hydrogen. These valves are mainly used in petrochemical, liquefied natural gas transportation, air separation units, and aerospace fields.

[0003] In the actual application of ultra-low temperature valves, multiphase flow is often encountered. During the transportation of liquefied natural gas, due to changes in temperature and pressure, some natural gas may vaporize. The existence of multiphase flow makes the properties of the fluid complicated, such as unstable density, which causes errors in the flow control accuracy of the control system. Because the traditional control algorithm designed based on single-phase flow may fail under multiphase flow, it is difficult for the control system to determine the valve closing time according to the set flow parameters. The liquid medium transported by the ultra-low temperature valve is generally in a high-pressure and low-temperature environment, and has high requirements for safety and reliability. The existing ultra-low temperature valves lack corresponding self-test functions. Therefore, improving the flow analysis of multiphase flow states and adding self-test functions are technical problems that technical personnel in this field need to solve. Summary of the invention

[0004] In view of the deficiencies in the prior art, the present invention provides a cryogenic valve control system and method, which solves the problems raised in the above-mentioned background technology.

[0005] To achieve the above objectives, the present invention is implemented through the following technical solutions: a super-low temperature valve control system, including a detection unit, a processing unit, a valve controller, a main valve, an auxiliary valve and a valve core pressure module, the detection unit includes a temperature module, a pipeline pressure module, an ultrasonic module and a diversion module;

[0006] The port of the ultrasonic module establishes communication with the port of the processing unit, the output ends of the temperature module and the pipeline pressure module are connected to the input end of the processing unit, the output end of the processing unit is connected to the input end of the diversion module, the port of the valve controller establishes communication with the port of the processing unit, the output end of the valve controller is respectively connected to the input ends of the main valve and the auxiliary valve, and the output end of the valve core pressure module is connected to the input end of the processing unit;

[0007] The temperature module obtains the temperature information of the medium in the valve and transmits it to the processing unit. The pipeline pressure module obtains the pressure information of the medium in the valve and transmits it to the processing unit. The processing unit determines whether the valve is in a multiphase flow state according to the temperature information and the pressure information. The processing unit sends a control instruction to the diversion module. The diversion module rotates in the valve to centrifugally divert the medium. The processing unit sends a collection instruction to the ultrasonic module. The ultrasonic module obtains the ultrasonic information of the medium in the valve and transmits it to the processing unit.

[0008] The processing unit sends a control instruction to the valve controller, and the valve controller drives the main valve and the auxiliary valve to open and close respectively. Furthermore, the main valve and the auxiliary valve are both valve opening and closing drive motors, and the valve controller is a motor driver. The valve controller sends a feedback message to the processing unit according to the pulse signal sent, and the processing unit determines the opening and closing degree of the main valve and the auxiliary valve according to the feedback message;

[0009] The ends of the main valve and the auxiliary valve are both spherical valve cores. The two spherical valve cores are placed side by side and move in the same direction. When the two spherical valve cores move to the maximum distance, the low-temperature valve is closed. The two spherical valve cores are in contact with and squeezed by the valve core pressure module. The valve core pressure module obtains the pressure information on its own surface and transmits it to the processing unit. The processing unit determines the tightness of the closure of the main valve and the auxiliary valve based on the pressure information;

[0010] The guide module is composed of a drive motor, a transmission mechanism and several guide vanes. The processing unit sends control instructions to control the start and stop and speed of the drive motor to realize the start and stop and centrifugal degree of the guide module. The output shaft of the drive motor drives the guide vanes to rotate with the medium flow direction as the axis through the transmission mechanism. The guide vanes drive the medium flow to rotate and perform centrifugal motion to achieve separation of multiphase flow medium.

[0011] The temperature module includes three temperature sensors, and the pipeline pressure module includes three pressure sensors. The temperature sensor and pressure sensor are located at the valve inlet, inside the valve and at the valve outlet respectively. The acquisition frequency of the temperature module and the pipeline pressure module is fixed at 1 time / second.

[0012] A method for controlling a cryogenic valve includes a multiphase flow control program and a tightness self-checking program. The multiphase flow control program includes the following steps:

[0013] Step 1: State detection, the processing unit obtains the temperature information of the temperature module and the pressure information of the pipeline pressure module in real time, calculates the temperature difference index k1, the temperature difference index k2, the pressure difference index k3 and the pressure difference index k4 according to the temperature information and the pressure information respectively, and judges whether the medium in the valve is in a multiphase flow state according to the values ​​of k1, k2, k3 and k4. If the processing unit judges that the medium in the valve is in a multiphase flow state, it proceeds to the next step;

[0014] Step 2: medium diversion, the processing unit sends a control instruction to the diversion module according to the values ​​of k1, k2, k3 and k4, the diversion module starts to drive the guide vane to rotate at a specified speed R in the valve, and the guide vane stirs the medium to rotate centrifugally in the valve;

[0015] Step 3: Fluid calculation: the processing unit sends a control instruction to the ultrasonic module, the ultrasonic module sends ultrasonic waves into the valve, the ultrasonic module receives ultrasonic information returned from the valve and transmits it to the processing unit, and the processing unit calculates the liquid percentage Per based on the ultrasonic information;

[0016] The radius r of the cylindrical passage inside the valve is preset inside the processing unit;

[0017] Step 4: Opening and closing control: the processing unit determines the time point when the valve is closed when the metering requirements are met according to the liquid proportion Per, and sends a control instruction to the valve controller. The valve controller controls the main valve and the auxiliary valve to close respectively, completing the valve closing operation;

[0018] The tightness self-test procedure includes the following steps:

[0019] Step 5: Determine the cycle, the processing unit records the valve operation data and analyzes and determines the valve self-test cycle Z;

[0020] Step 6: Alternate detection, the processing unit sends a control instruction to the valve controller, the valve controller controls the main valve and the auxiliary valve to start alternately within the valve core deformation range, marks the critical point of the main valve and the critical point of the auxiliary valve, and the valve controller controls the main valve and the auxiliary valve to open and close alternately, and outputs a warning signal if the detection is unqualified;

[0021] Step 7: Record logs. The processing unit records the operation logs, creates warning events and sorts the warning events.

[0022] Furthermore, the state detection specifically includes the following steps:

[0023] Step 101: The processing unit establishes a temperature curve table, the vertical axis of the temperature curve table is temperature, and the horizontal axis of the temperature curve table is time. The processing unit obtains temperature information from the temperature module and marks it. The temperature information obtained by the temperature sensor at the valve inlet is marked as t1, the temperature information obtained by the temperature sensor inside the valve is marked as t2, and the temperature information obtained by the temperature sensor at the valve outlet is marked as t3. The processing unit subtracts temperature t1 from temperature t2 to obtain a temperature difference Δt1 from the valve inlet to the inside of the valve. The processing unit subtracts temperature t2 from temperature t3 to obtain a temperature difference Δt2 from the inside of the valve to the valve outlet. The processing unit inputs the temperature difference Δt1 and the temperature difference Δt2 into the temperature curve table respectively, and obtains a first temperature difference curve and a second temperature difference curve in sequence.

[0024] Step 102: The processing unit establishes a pressure curve table, the vertical axis of the pressure curve table is pressure, and the horizontal axis of the pressure curve table is time. The processing unit obtains pressure information from the pipeline pressure module and marks it. The pressure information obtained by the pressure sensor at the valve inlet is marked as p1, the pressure information obtained by the pressure sensor inside the valve is marked as p2, and the pressure information obtained by the pressure sensor at the valve outlet is marked as p3. The processing unit subtracts the pressure p1 from the pressure p2 to obtain the pressure difference Δp1 from the valve inlet to the inside of the valve. The processing unit subtracts the pressure p2 from the pressure p3 to obtain the pressure difference Δp2 from the inside of the valve to the valve outlet. The processing unit inputs the pressure difference Δp1 and the pressure difference Δp2 into the pressure curve table respectively, and obtains the first pressure difference curve and the second pressure difference curve in sequence.

[0025] Step 103: Processing unit according to formula The temperature difference index k1 of the first temperature difference curve and the temperature difference index k2 of the second temperature difference curve are calculated respectively, i is a point on the first temperature difference curve, j is a point on the second temperature difference curve, Δt i is the temperature difference at time point Mi in the first temperature difference curve, Δt i+1 is the temperature difference one second after time point Mi in the first temperature difference curve, Δtj is the temperature difference at time point Mj in the second temperature difference curve, Δtj-1 is the temperature difference one second before time point Mj in the second temperature difference curve, is the average value of the first temperature difference curve, is the average value of the second temperature difference curve;

[0026] Step 104: Processing unit according to formula Calculate the pressure difference index k3 of the first pressure difference curve and the pressure difference index k4 of the second pressure difference curve respectively, n is the number of points on the first pressure difference curve, a is the point on the first pressure difference curve, m is the number of points on the second pressure difference curve, b is the point on the second pressure difference curve, pa is the pressure difference corresponding to point a on the first pressure difference curve, pb is the pressure difference corresponding to point b on the second pressure difference curve, is the average value of the first pressure difference curve, is the average value of the second pressure difference curve;

[0027] Step 105: The processing unit presets condition one and condition two, condition one is k2≥1.2k1 and k1≥0.3, condition two is k4≥1.75k3 and k1≥0.42. When condition one and condition two are met at the same time, the processing unit determines that the medium in the valve produces a multiphase flow state and executes the next step. Otherwise, if either condition one or condition two is not met, steps 101 to 105 are re-executed.

[0028] Furthermore, the calculation of the rotation speed R specifically includes the following steps:

[0029] Step 201: The processing unit presets a speed R and initializes the value to 3000 rpm, the value range of the speed R is 800 rpm-3000 rpm, the processing unit converts the speed R into a control instruction and transmits it to the guide module, and the guide module drives the guide vane to rotate in the valve according to the speed R;

[0030] Step 202: After the processing unit sends the control instruction, the values ​​of k1, k2, k3 and k4 are updated in real time. The processing unit presets conditions three and four. Condition three is that the temperature difference index k1 increases by 5% or the temperature difference index k2 increases by 8% month-on-month. Condition four is that the pressure difference index k3 increases by 10% or the pressure difference index k4 increases by 16% month-on-month.

[0031] Step 203: Each time condition three is triggered, the value of the speed R decreases by 10% to the lowest value, and each time condition four is triggered, the value of the speed R decreases by 25% to the lowest value, to prevent the agitation of the guide module from aggravating the gasification of the liquid in the multiphase flow medium, thereby ensuring the safe operation of the valve.

[0032] Furthermore, the ultrasonic information is the time domain data Tb of the reflected wave of the liquid medium, and the calculation of the liquid proportion Per specifically includes the following steps:

[0033] Step 301: The processing unit obtains pressure information from the pipeline pressure module and marks it as p4. The processing unit calculates the pressure information according to the formula Calculate the ultrasonic propagation velocity v1, K is the bulk elastic modulus of the liquid medium, γ is the specific heat ratio of the gas medium, ρ1 is the density of the liquid medium, ρ2 is the density of the gas medium, the values ​​of K, γ, ρ1 and ρ2 are all constants, p4 is the pressure information obtained by the pressure sensor at the inlet end of the valve, and k3 is the pressure difference index of the first pressure difference curve;

[0034] Step 302: The processing unit calculates the Calculate the liquid proportion Per of the liquid medium in the valve, where r is the radius of the cylindrical channel inside the valve.

[0035] Furthermore, the opening and closing control specifically includes the following steps:

[0036] Step 401: manually input the cut-off amount Q required for measurement into the processing unit, and the processing unit sends a control instruction to the ultrasonic module. The ultrasonic module sends ultrasonic waves twice to the inside of the valve at a fixed angle, and the ultrasonic module receives the ultrasonic information returned from the valve and transmits it to the processing unit;

[0037] Step 402: The processing unit converts the ultrasonic information received twice into a waveform image. The waveform image recorded for the first time is recorded as The waveform image recorded for the second time is recorded as

[0038] Step 403: The processing unit calculates the Calculate the flow velocity v2 of the liquid medium, δ is the wavelength of the ultrasonic wave, r is the radius of the cylindrical channel inside the valve, θ is the angle between the ultrasonic wave emission direction and the fluid flow direction in the pipeline, and f is the frequency of the ultrasonic wave. The flow velocity v2 of the liquid medium in the valve pipeline is calculated by the phase difference. The liquid medium here refers to liquefied natural gas, and the gas medium refers to gasified natural gas.

[0039] Step 404: The processing unit calculates the The closing time Ts of the main valve is calculated, where Per is the liquid proportion of the liquid medium in the valve. The processing unit converts the closing time Ts into a control instruction and sends it to the valve controller. The valve controller drives the main valve to close at the closing time Ts. By calculating the liquid proportion Per of the liquid medium, the closing time Ts of the main valve is determined to avoid the medium in the cryogenic valve affecting the accuracy of the cut-off volume Q under the multiphase flow state, so that the flow rate of the liquid medium passing through the cryogenic valve meets the requirements.

[0040] Furthermore, determining the cycle specifically includes the following steps:

[0041] Step 501: the valve controller records the opening and closing times e of the main valve and transmits it to the processing unit. The processing unit records the number of times the diversion module is started g. The valve controller records the opening time RT of the main valve. The opening time RT, the number of times e and the number of times g are combined into valve operation data.

[0042] Step 502: The processing unit calculates the Calculate the valve self-test period Z, li is the design life of the valve, k1 and k2 are the temperature difference index, k3 and k4 are the pressure difference index;

[0043] Step 503: The processing unit obtains the values ​​of the opening time RT, the number of times e and the number of times g in real time, and synchronously updates the value of the self-test period Z. After the time of the self-test period is reached, the processing unit executes the next alternating detection step.

[0044] Furthermore, the alternating detection specifically includes the following steps:

[0045] Step 601: The processing unit presets a trigger threshold of 5%. When the auxiliary valve is closed, the processing unit sends a control instruction to the valve controller, and the valve controller drives the main valve to open slowly. The processing unit obtains pressure information from the pipeline pressure module in real time, and the processing unit obtains pressure information from the valve core pressure module. The processing unit divides the pressure information by the pressure information to obtain a pressure ratio. When the pressure ratio is greater than the trigger threshold, the valve controller controls the main valve to stop. The processing unit records the pressure information of the valve pressure module and marks it as the critical point of the main valve. When the pressure information applied by the main valve to the valve core pressure module in the closed state is lower than the critical point of the main valve, jump to step 606, otherwise, go to the next step;

[0046] Step 602: the valve controller drives the main valve to open and close once. When the main valve is closed again, the processing unit obtains the pressure information applied by the main valve in the valve core pressure module. The processing unit compares the pressure information with the pressure information when the main valve was closed last time. If the pressure information of the two times is the same, it goes to the next step. If the pressure information of the two times is different, it jumps to step 606. Step 603: the valve controller drives the main valve to close, and the valve controller drives the auxiliary valve to open slowly. The processing unit obtains the pressure information from the pipeline pressure module in real time. The processing unit obtains the pressure information from the valve core pressure module. The processing unit divides the pressure information by the pressure information to obtain the pressure ratio. When the pressure ratio is greater than the trigger threshold, the valve controller controls the auxiliary valve to stop. The processing unit records the pressure information of the valve pressure module and marks it as the critical point of the auxiliary valve. When the pressure information applied by the auxiliary valve to the valve core pressure module in the closed state is lower than the critical point of the auxiliary valve, it jumps to step 606. Otherwise, it goes to the next step.

[0047] Step 604: the valve controller drives the auxiliary valve to open and close once. When the auxiliary valve is closed again, the processing unit obtains the pressure information applied by the auxiliary valve in the valve core pressure module. The processing unit compares the pressure information with the pressure information when the auxiliary valve was closed last time. If the pressure information of the two times is the same, the next step is entered. If the pressure information of the two times is different, the process jumps to step 606.

[0048] Step 605: the processing unit outputs that the alternating detection is qualified, and stops executing the steps;

[0049] Step 606: The processing unit outputs a warning signal.

[0050] Furthermore, recording the log specifically includes the following steps:

[0051] Step 701: The processing unit saves all output warning signals, synchronizes the time when the warning signals are output, and records the operation log in chronological order;

[0052] Step 702: The processing unit marks the warning signal exceeding the critical point of the main valve as an important event, marks the warning signal exceeding the critical point of the auxiliary valve as a minor event, and marks the warning signal with different pressure information before and after the main valve and the auxiliary valve are opened and closed as a general event;

[0053] Step 703: The processing unit sets the order of importance of events as: important events > minor events > general events. The processing unit re-sorts the operation logs according to the order of importance of events, and displays important events and minor events first.

[0054] The present invention has the following beneficial effects:

[0055] 1. By calculating the temperature difference index and pressure difference index, determine whether there is a multiphase flow state in the valve, use the diversion module to separate the gas and liquid media, and then use the ultrasonic module to calculate the proportion of liquid media to avoid the influence of multiphase flow on the flow control accuracy.

[0056] 2. By recording the temperature difference index, pressure difference index and valve operation data to calculate the self-checking cycle, the valve controller drives the main valve and the auxiliary valve to perform self-checking alternately, and judges whether the valve function is normal according to the pressure information, thereby improving the safety and reliability of the valve. Of course, any product implementing the present invention does not necessarily need to achieve all of the above advantages at the same time. BRIEF DESCRIPTION OF THE DRAWINGS

[0057] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings required for describing the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other accompanying drawings can be obtained based on these accompanying drawings without paying creative work.

[0058] Figure 1 This is a block diagram of a super-low temperature valve control system of the present invention;

[0059] Figure 2 It is a schematic flow chart of the multiphase flow control program of the present invention;

[0060] Figure 3 It is a schematic diagram of the process of alternating detection of the present invention. DETAILED DESCRIPTION

[0061] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. 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 creative work are within the scope of protection of the present invention.

[0062] See also Figure 1-3 , the present invention provides a technical solution: a super-low temperature valve control system, including a detection unit, a processing unit, a valve controller, a main valve, an auxiliary valve and a valve core pressure module, the detection unit includes a temperature module, a pipeline pressure module, an ultrasonic module and a diversion module;

[0063] like Figure 1 As shown, the port of the ultrasonic module establishes communication with the port of the processing unit, the output ends of the temperature module and the pipeline pressure module are connected to the input end of the processing unit, the output end of the processing unit is connected to the input end of the diversion module, the port of the valve controller establishes communication with the port of the processing unit, the output end of the valve controller is respectively connected to the input ends of the main valve and the auxiliary valve, and the output end of the valve core pressure module is connected to the input end of the processing unit;

[0064] The temperature module obtains the temperature information of the medium in the valve and transmits it to the processing unit. The pipeline pressure module obtains the pressure information of the medium in the valve and transmits it to the processing unit. The processing unit determines whether the valve is in a multiphase flow state according to the temperature information and the pressure information. The processing unit sends a control instruction to the diversion module. The diversion module rotates in the valve to centrifugally divert the medium. The processing unit sends a collection instruction to the ultrasonic module. The ultrasonic module obtains the ultrasonic information of the medium in the valve and transmits it to the processing unit.

[0065] The processing unit sends a control command to the valve controller, and the valve controller drives the main valve and the auxiliary valve to open and close respectively. The main valve and the auxiliary valve are both valve opening and closing drive motors, and the valve controller is a motor driver. The valve controller sends a feedback message to the processing unit according to the pulse signal sent, and the processing unit determines the opening and closing degree of the main valve and the auxiliary valve according to the feedback message;

[0066] The ends of the main valve and the auxiliary valve are both spherical valve cores. The two spherical valve cores are placed side by side and move in the same direction. When the two spherical valve cores move to the maximum distance, the low-temperature valve is closed. The two spherical valve cores are in contact with and squeezed by the valve core pressure module. The valve core pressure module obtains the pressure information on its own surface and transmits it to the processing unit. The processing unit determines the tightness of the closure of the main valve and the auxiliary valve based on the pressure information;

[0067] The guide module is composed of a drive motor, a transmission mechanism and four guide vanes. The processing unit sends control instructions to control the start and stop and speed of the drive motor to realize the start and stop and centrifugal degree of the guide module. The output shaft of the drive motor drives the guide vanes to rotate with the medium flow direction as the axis through the transmission mechanism. The guide vanes drive the medium flow to rotate and perform centrifugal motion to achieve separation of multiphase flow media.

[0068] The temperature module includes three temperature sensors, and the pipeline pressure module includes three pressure sensors. The temperature sensor and pressure sensor are located at the valve inlet, inside the valve and at the valve outlet respectively. The acquisition frequency of the temperature module and the pipeline pressure module is fixed at 1 time / second.

[0069] A method for controlling a cryogenic valve includes a multiphase flow control program and a tightness self-checking program. Figure 2 As shown, the multiphase flow control procedure includes the following steps:

[0070] Step 1: State detection, the processing unit obtains the temperature information of the temperature module and the pressure information of the pipeline pressure module in real time, calculates the temperature difference index k1, the temperature difference index k2, the pressure difference index k3 and the pressure difference index k4 according to the temperature information and the pressure information respectively, and judges whether the medium in the valve is in a multiphase flow state according to the values ​​of k1, k2, k3 and k4. If the processing unit judges that the medium in the valve is in a multiphase flow state, it proceeds to the next step;

[0071] Step 2: medium diversion, the processing unit sends a control instruction to the diversion module according to the values ​​of k1, k2, k3 and k4, the diversion module starts to drive the guide vane to rotate at a specified speed R in the valve, and the guide vane stirs the medium to rotate centrifugally in the valve;

[0072] Step 3: Fluid calculation: the processing unit sends a control instruction to the ultrasonic module, the ultrasonic module sends ultrasonic waves into the valve, the ultrasonic module receives ultrasonic information returned from the valve and transmits it to the processing unit, and the processing unit calculates the liquid percentage Per based on the ultrasonic information;

[0073] The radius r of the cylindrical passage inside the valve is preset inside the processing unit;

[0074] Step 4: Opening and closing control: the processing unit determines the time point when the valve is closed when the metering requirements are met according to the liquid proportion Per, and sends a control instruction to the valve controller. The valve controller controls the main valve and the auxiliary valve to close respectively, completing the valve closing operation;

[0075] The tightness self-test procedure includes the following steps:

[0076] Step 5: Determine the cycle, the processing unit records the valve operation data and analyzes and determines the valve self-test cycle Z;

[0077] Step 6: Alternate detection, the processing unit sends a control instruction to the valve controller, the valve controller controls the main valve and the auxiliary valve to start alternately within the valve core deformation range, marks the critical point of the main valve and the critical point of the auxiliary valve, and the valve controller controls the main valve and the auxiliary valve to open and close alternately, and outputs a warning signal if the detection is unqualified;

[0078] Step 7: Record logs. The processing unit records the operation logs, establishes warning events and sorts the warning events. Among them, the status detection specifically includes the following steps:

[0079] Step 101: The processing unit establishes a temperature curve table, the vertical axis of the temperature curve table is temperature, and the horizontal axis of the temperature curve table is time. The processing unit obtains temperature information from the temperature module and marks it. The temperature information obtained by the temperature sensor at the valve inlet is marked as t1, the temperature information obtained by the temperature sensor inside the valve is marked as t2, and the temperature information obtained by the temperature sensor at the valve outlet is marked as t3. The processing unit subtracts temperature t1 from temperature t2 to obtain a temperature difference Δt1 from the valve inlet to the inside of the valve. The processing unit subtracts temperature t2 from temperature t3 to obtain a temperature difference Δt2 from the inside of the valve to the valve outlet. The processing unit inputs the temperature difference Δt1 and the temperature difference Δt2 into the temperature curve table respectively, and obtains a first temperature difference curve and a second temperature difference curve in sequence.

[0080] Step 102: The processing unit establishes a pressure curve table, the vertical axis of the pressure curve table is pressure, and the horizontal axis of the pressure curve table is time. The processing unit obtains pressure information from the pipeline pressure module and marks it. The pressure information obtained by the pressure sensor at the valve inlet is marked as p1, the pressure information obtained by the pressure sensor inside the valve is marked as p2, and the pressure information obtained by the pressure sensor at the valve outlet is marked as p3. The processing unit subtracts the pressure p1 from the pressure p2 to obtain the pressure difference Δp1 from the valve inlet to the inside of the valve. The processing unit subtracts the pressure p2 from the pressure p3 to obtain the pressure difference Δp2 from the inside of the valve to the valve outlet. The processing unit inputs the pressure difference Δp1 and the pressure difference Δp2 into the pressure curve table respectively, and obtains the first pressure difference curve and the second pressure difference curve in sequence.

[0081] Step 103: Processing unit according to formula The temperature difference index k1 of the first temperature difference curve and the temperature difference index k2 of the second temperature difference curve are calculated respectively, i is a point on the first temperature difference curve, j is a point on the second temperature difference curve, Δt i is the temperature difference at time point Mi in the first temperature difference curve, Δt i+1 is the temperature difference one second after time point Mi in the first temperature difference curve, Δtj is the temperature difference at time point Mj in the second temperature difference curve, Δtj-1 is the temperature difference one second before time point Mj in the second temperature difference curve, is the average value of the first temperature difference curve, is the average value of the second temperature difference curve;

[0082] Step 104: Processing unit according to formula Calculate the pressure difference index k3 of the first pressure difference curve and the pressure difference index k4 of the second pressure difference curve respectively, n is the number of points on the first pressure difference curve, a is the point on the first pressure difference curve, m is the number of points on the second pressure difference curve, b is the point on the second pressure difference curve, pa is the pressure difference corresponding to point a on the first pressure difference curve, pb is the pressure difference corresponding to point b on the second pressure difference curve, is the average value of the first pressure difference curve, is the average value of the second pressure difference curve;

[0083] Step 105: The processing unit presets condition one and condition two, condition one is k2≥1.2k1 and k1≥0.3, condition two is k4≥1.75k3 and k1≥0.42. When condition one and condition two are met at the same time, the processing unit determines that the medium in the valve produces a multiphase flow state and executes the next step. Otherwise, if either condition one or condition two is not met, steps 101 to 105 are re-executed.

[0084] The calculation of the rotation speed R specifically includes the following steps:

[0085] Step 201: The processing unit presets a speed R and initializes the value to 3000 rpm, the value range of the speed R is 800 rpm-3000 rpm, the processing unit converts the speed R into a control instruction and transmits it to the guide module, and the guide module drives the guide vane to rotate in the valve according to the speed R;

[0086] Step 202: After the processing unit sends the control instruction, the values ​​of k1, k2, k3 and k4 are updated in real time. The processing unit presets conditions three and four. Condition three is that the temperature difference index k1 increases by 5% or the temperature difference index k2 increases by 8% month-on-month. Condition four is that the pressure difference index k3 increases by 10% or the pressure difference index k4 increases by 16% month-on-month.

[0087] Step 203: Each time condition three is triggered, the value of the speed R decreases by 10% to the lowest value, and each time condition four is triggered, the value of the speed R decreases by 25% to the lowest value, to prevent the agitation of the guide module from aggravating the gasification of the liquid in the multiphase flow medium, thereby ensuring the safe operation of the valve.

[0088] The ultrasonic information is the time domain data Tb of the reflected wave of the liquid medium, and the calculation of the liquid proportion Per specifically includes the following steps:

[0089] Step 301: The processing unit obtains pressure information from the pipeline pressure module and marks it as p4. The processing unit calculates the pressure information according to the formula Calculate the ultrasonic propagation velocity v1, K is the bulk elastic modulus of the liquid medium, γ is the specific heat ratio of the gas medium, ρ1 is the density of the liquid medium, ρ2 is the density of the gas medium, the values ​​of K, γ, ρ1 and ρ2 are all constants, p4 is the pressure information obtained by the pressure sensor at the inlet end of the valve, and k3 is the pressure difference index of the first pressure difference curve;

[0090] Step 302: The processing unit calculates the Calculate the liquid proportion Per of the liquid medium in the valve, where r is the radius of the cylindrical channel inside the valve.

[0091] The opening and closing control specifically includes the following steps:

[0092] Step 401: manually input the cutoff value Q to the processing unit, the processing unit sends a control instruction to the ultrasonic module, the ultrasonic module sends ultrasonic waves twice to the inside of the valve at a fixed angle, the ultrasonic module receives the ultrasonic information returned from the valve and transmits it to the processing unit;

[0093] Step 402: The processing unit converts the ultrasonic information received twice into a waveform image. The waveform image recorded for the first time is recorded as The waveform image recorded for the second time is recorded as

[0094] Step 403: The processing unit calculates the Calculate the flow velocity v2 of the liquid medium, δ is the wavelength of the ultrasonic wave, r is the radius of the cylindrical channel inside the valve, θ is the angle between the ultrasonic wave emission direction and the fluid flow direction in the pipeline, and f is the frequency of the ultrasonic wave. The flow velocity v2 of the liquid medium in the valve pipeline is calculated by the phase difference. The liquid medium here refers to liquefied natural gas, and the gas medium refers to gasified natural gas.

[0095] Step 404: The processing unit calculates the The closing time Ts of the main valve is calculated, where Per is the liquid proportion of the liquid medium in the valve. The processing unit converts the closing time Ts into a control instruction and sends it to the valve controller. The valve controller drives the main valve to close at the closing time Ts. By calculating the liquid proportion Per of the liquid medium, the closing time Ts of the main valve is determined to avoid the medium in the cryogenic valve affecting the accuracy of the cut-off volume Q under the multiphase flow state, so that the flow rate of the liquid medium passing through the cryogenic valve meets the requirements.

[0096] Wherein, determining the cycle specifically includes the following steps:

[0097] Step 501: the valve controller records the opening and closing times e of the main valve and transmits it to the processing unit. The processing unit records the number of times the diversion module is started g. The valve controller records the opening time RT of the main valve. The opening time RT, the number of times e and the number of times g are combined into valve operation data.

[0098] Step 502: The processing unit calculates the Calculate the valve self-test period Z, li is the design life of the valve, k1 and k2 are the temperature difference index, k3 and k4 are the pressure difference index;

[0099] Step 503: The processing unit obtains the values ​​of the opening time RT, the number of times e and the number of times g in real time, and synchronously updates the value of the self-test period Z. After the time of the self-test period is reached, the processing unit executes the next alternating detection step.

[0100] Among them, Figure 3 As shown, the alternating detection specifically includes the following steps:

[0101] Step 601: The processing unit presets a trigger threshold of 5%. When the auxiliary valve is closed, the processing unit sends a control instruction to the valve controller, and the valve controller drives the main valve to open slowly. The processing unit obtains pressure information from the pipeline pressure module in real time, and the processing unit obtains pressure information from the valve core pressure module. The processing unit divides the pressure information by the pressure information to obtain a pressure ratio. When the pressure ratio is greater than the trigger threshold, the valve controller controls the main valve to stop. The processing unit records the pressure information of the valve pressure module and marks it as the critical point of the main valve. When the pressure information applied by the main valve to the valve core pressure module in the closed state is lower than the critical point of the main valve, jump to step 606, otherwise, go to the next step;

[0102] Step 602: the valve controller drives the main valve to open and close once. When the main valve is closed again, the processing unit obtains the pressure information applied by the main valve in the valve core pressure module. The processing unit compares the pressure information with the pressure information when the main valve was closed last time. If the pressure information of the two times is the same, it goes to the next step. If the pressure information of the two times is different, it jumps to step 606. Step 603: the valve controller drives the main valve to close, and the valve controller drives the auxiliary valve to open slowly. The processing unit obtains the pressure information from the pipeline pressure module in real time. The processing unit obtains the pressure information from the valve core pressure module. The processing unit divides the pressure information by the pressure information to obtain the pressure ratio. When the pressure ratio is greater than the trigger threshold, the valve controller controls the auxiliary valve to stop. The processing unit records the pressure information of the valve pressure module and marks it as the critical point of the auxiliary valve. When the pressure information applied by the auxiliary valve to the valve core pressure module in the closed state is lower than the critical point of the auxiliary valve, it jumps to step 606. Otherwise, it goes to the next step.

[0103] Step 604: the valve controller drives the auxiliary valve to open and close once. When the auxiliary valve is closed again, the processing unit obtains the pressure information applied by the auxiliary valve in the valve core pressure module. The processing unit compares the pressure information with the pressure information when the auxiliary valve was closed last time. If the pressure information of the two times is the same, the next step is entered. If the pressure information of the two times is different, the process jumps to step 606.

[0104] Step 605: the processing unit outputs that the alternating detection is qualified, and stops executing the steps;

[0105] Step 606: The processing unit outputs a warning signal.

[0106] The log recording process specifically includes the following steps:

[0107] Step 701: The processing unit saves all output warning signals, synchronizes the time when the warning signals are output, and records the operation log in chronological order;

[0108] Step 702: The processing unit marks the warning signal exceeding the critical point of the main valve as an important event, marks the warning signal exceeding the critical point of the auxiliary valve as a minor event, and marks the warning signal with different pressure information before and after the main valve and the auxiliary valve are opened and closed as a general event;

[0109] Step 703: The processing unit sets the order of importance of events as: important events > minor events > general events. The processing unit re-sorts the operation logs according to the order of importance of events, and displays important events and minor events first.

[0110] The above are only preferred specific implementation modes of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can make equivalent replacements or changes according to the technical solutions and inventive concepts of the present invention within the technical scope disclosed by the present invention, which should be covered by the protection scope of the present invention.

Claims

1. A cryogenic valve control system, comprising a detection unit, a processing unit, a valve controller, a main valve, an auxiliary valve and a valve core pressure module, characterized in that: The detection unit includes a temperature module, a pipeline pressure module, an ultrasonic module and a flow guide module; The port of the ultrasonic module establishes communication with the port of the processing unit, the output ends of the temperature module and the pipeline pressure module are connected to the input end of the processing unit, the output end of the processing unit is connected to the input end of the diversion module, the port of the valve controller establishes communication with the port of the processing unit, the output end of the valve controller is respectively connected to the input ends of the main valve and the auxiliary valve, and the output end of the valve core pressure module is connected to the input end of the processing unit; The temperature module obtains the temperature information of the medium in the valve and transmits it to the processing unit, the pipeline pressure module obtains the pressure information of the medium in the valve and transmits it to the processing unit, the processing unit sends a control instruction to the diversion module, the diversion module rotates in the valve to centrifugally divert the medium, the processing unit sends a collection instruction to the ultrasonic module, the ultrasonic module obtains the ultrasonic information of the medium in the valve and transmits it to the processing unit; The processing unit sends a control instruction to the valve controller, and the valve controller drives the main valve and the auxiliary valve to open and close respectively.

2. The ultra-low temperature valve control system according to claim 1, characterized in that: The main valve and the auxiliary valve are both valve opening and closing drive motors, the valve controller is the motor driver, the valve controller sends a feedback message to the processing unit, and the processing unit determines the opening and closing degree of the main valve and the auxiliary valve; The ends of the main valve and the auxiliary valve are both spherical valve cores, the two spherical valve cores are placed side by side and move in the same direction, the valves are closed when the two spherical valve cores move to the maximum distance, the two spherical valve cores are in contact with and squeezed by the valve core pressure module, and the valve core pressure module obtains the pressure information on its own surface and transmits it to the processing unit; The guide module is composed of a driving motor, a transmission mechanism and a plurality of guide vanes. The processing unit sends a control instruction to control the start and stop and the speed of the driving motor. The output shaft of the driving motor drives the guide vanes to rotate with the medium flow direction as the axis through the transmission mechanism. The guide vanes drive the medium flow to rotate and perform centrifugal motion. The temperature module includes a plurality of temperature sensors, and the pipeline pressure module includes a plurality of pressure sensors. The temperature sensors and the pressure sensors are respectively located at the valve inlet, inside the valve and at the valve outlet.

3. A method for controlling a cryogenic valve, characterized in that A cryogenic valve control system applied to any one of claims 1-2, comprising a multiphase flow control program and a tightness self-test program, wherein the multiphase flow control program comprises the following steps: Step 1: State detection: the processing unit obtains the temperature information of the temperature module and the pressure information of the pipeline pressure module in real time, calculates the temperature difference index k1, temperature difference index k2, pressure difference index k3 and pressure difference index k4 respectively, and determines whether the medium in the valve is in a multiphase flow state. If the medium in the valve is in a multiphase flow state, proceed to the next step; Step 2: medium diversion, the processing unit sends a control instruction to the diversion module, the diversion module starts to drive the guide vane to rotate at a specified speed R in the valve, and the guide vane stirs the medium to rotate centrifugally in the valve; Step 3: Fluid calculation: the processing unit sends a control instruction to the ultrasonic module, the ultrasonic module sends ultrasonic waves into the valve, the ultrasonic module receives the ultrasonic information returned from the valve and transmits it to the processing unit to calculate the liquid percentage Per; The radius r of the cylindrical passage inside the valve is preset inside the processing unit; Step 4: Opening and closing control, determine the closing time Ts of the valve when it meets the metering requirements, send a control command to the valve controller, and the valve controller controls the main valve and the auxiliary valve to close respectively, completing the valve closing operation; The tightness self-test procedure includes the following steps: Step 5: Determine the cycle, record the valve operation data and analyze and determine the valve self-test cycle Z; Step 6: Alternate detection, the processing unit sends a control instruction to the valve controller, the valve controller controls the main valve and the auxiliary valve to start alternately within the valve core deformation range, marks the critical point of the main valve and the critical point of the auxiliary valve, and the valve controller controls the main valve and the auxiliary valve to open and close alternately, and outputs a warning signal if the detection is unqualified; Step 7: Record the operation log, establish warning events and sort the warning events.

4. A method for controlling a cryogenic valve according to claim 3, characterized in that: The status detection specifically includes the following steps: Step 101: The processing unit establishes a temperature curve table, the vertical axis of the temperature curve table is temperature, and the horizontal axis is time. The processing unit obtains temperature information from the temperature module and marks it. The temperature information obtained by the temperature sensor at the valve inlet is marked as t1, the temperature information obtained by the temperature sensor inside the valve is marked as t2, and the temperature information obtained by the temperature sensor at the valve outlet is marked as t3. The temperature difference Δt1 from the valve inlet to the inside of the valve is obtained by subtracting the temperature t1 from the temperature t2, and the temperature difference Δt2 from the temperature t3 is obtained by subtracting the temperature t2 from the temperature t3. The temperature difference Δt1 and the temperature difference Δt2 are respectively input into the temperature curve table to obtain a first temperature difference curve and a second temperature difference curve in sequence; Step 102: The processing unit establishes a pressure curve table, the vertical axis of the pressure curve table is pressure, and the horizontal axis is time. The processing unit obtains pressure information from the pipeline pressure module and marks it. The pressure information obtained by the pressure sensor at the valve inlet is marked as p1, the pressure information obtained by the pressure sensor inside the valve is marked as p2, and the pressure information obtained by the pressure sensor at the valve outlet is marked as p3. The pressure difference Δp1 from the valve inlet to the inside of the valve is obtained by subtracting the pressure p1 from the pressure p2, and the pressure difference Δp2 from the inside of the valve to the valve outlet is obtained by subtracting the pressure p2 from the pressure p3. The pressure difference Δp1 and the pressure difference Δp2 are respectively input into the pressure curve table to obtain a first pressure difference curve and a second pressure difference curve in sequence. Step 103: According to the formula The temperature difference index k1 of the first temperature difference curve and the temperature difference index k2 of the second temperature difference curve are calculated respectively, i is a point on the first temperature difference curve, j is a point on the second temperature difference curve, Δti is the temperature difference at time point Mi in the first temperature difference curve, Δti+1 is the temperature difference one second after time point Mi in the first temperature difference curve, Δtj is the temperature difference at time point Mj in the second temperature difference curve, Δtj-1 is the temperature difference one second before time point Mj in the second temperature difference curve, is the average value of the first temperature difference curve, is the average value of the second temperature difference curve; Step 104: According to the formula Calculate the pressure difference index k3 of the first pressure difference curve and the pressure difference index k4 of the second pressure difference curve respectively, n is the number of points on the first pressure difference curve, a is the point on the first pressure difference curve, m is the number of points on the second pressure difference curve, b is the point on the second pressure difference curve, pa is the pressure difference corresponding to point a on the first pressure difference curve, pb is the pressure difference corresponding to point b on the second pressure difference curve, is the average value of the first pressure difference curve, is the average value of the second pressure difference curve; Step 105: The processing unit presets condition one and condition two, condition one is k2≥1.2k1 and k1≥0.3, condition two is k4≥1.75k3 and k1≥0.

42. When condition one and condition two are met at the same time, it is determined that the medium in the valve produces a multiphase flow state and the next step is executed. Otherwise, if either condition one or condition two is not met, steps 101 to 105 are re-executed.

5. The ultra-low temperature valve control method according to claim 3, characterized in that: The calculation of the speed R specifically includes the following steps: Step 201: The processing unit presets and initializes the rotation speed R, converts the rotation speed R into a control instruction and transmits it to the guide module, and the guide module drives the guide vane to rotate in the valve according to the rotation speed R; Step 202: After the processing unit sends the control instruction, the values ​​of k1, k2, k3 and k4 are updated in real time, and conditions three and four are preset. Condition three is that the temperature difference index k1 increases by 5% or the temperature difference index k2 increases by 8% month-on-month, and condition four is that the pressure difference index k3 increases by 10% or the pressure difference index k4 increases by 16% month-on-month; Step 203: Each time the condition three is triggered, the value of the rotation speed R decreases by 10% until it reaches the lowest value; each time the condition four is triggered, the value of the rotation speed R decreases by 25% until it reaches the lowest value.

6. A method for controlling a cryogenic valve according to claim 3, characterized in that: The ultrasonic information is the time domain data Tb of the reflected wave of the liquid medium. The calculation of the liquid proportion Per specifically includes the following steps: Step 301: The processing unit obtains pressure information from the pipeline pressure module and marks it as p4. According to the formula Calculate the ultrasonic propagation velocity v1, K is the bulk elastic modulus of the liquid medium, γ is the specific heat ratio of the gas medium, ρ1 is the density of the liquid medium, ρ2 is the density of the gas medium, p4 is the pressure information obtained by the pressure sensor at the inlet end of the valve, and k3 is the pressure difference index; Step 302: According to the formula Calculate the liquid proportion Per of the liquid medium in the valve, where r is the radius of the cylindrical channel inside the valve.

7. A method for controlling a cryogenic valve according to claim 3, characterized in that: The opening and closing control specifically includes the following steps: Step 401: input the cut-off amount Q required for measurement into the processing unit, the processing unit sends a control instruction to the ultrasonic module, the ultrasonic module sends ultrasonic waves twice into the valve at a fixed angle, the ultrasonic module receives the ultrasonic information returned from the valve and transmits it to the processing unit; Step 402: Convert the ultrasonic information received twice into a waveform image. The waveform image recorded for the first time is recorded as The waveform image recorded for the second time is recorded as Step 403: According to the formula Calculate the flow velocity v2 of the liquid medium, δ is the wavelength of the ultrasonic wave, r is the radius of the cylindrical channel inside the valve, θ is the angle between the ultrasonic wave emission direction and the fluid flow direction in the pipeline, and f is the frequency of the ultrasonic wave; Step 404: According to the formula Calculate the closing time Ts of the main valve, where Per is the liquid ratio of the liquid medium in the valve. Convert the closing time Ts into a control command and send it to the valve controller. The valve controller drives the main valve to close at the closing time Ts.

8. The ultra-low temperature valve control method according to claim 3, characterized in that: Determining the cycle specifically includes the following steps: Step 501: the valve controller records the opening and closing times e of the main valve and transmits it to the processing unit, records the number of times the diversion module is started g, and the valve controller records the opening time RT of the main valve. The opening time RT, the number of times e and the number of times g are combined into valve operation data; Step 502: According to the formula Calculate the valve self-test period Z, li is the design life of the valve, k1 and k2 are the temperature difference index, k3 and k4 are the pressure difference index; Step 503: Acquire the values ​​of the opening time RT, the number of times e and the number of times g in real time, and synchronously update the value of the self-test period Z. After the time of the self-test period is reached, execute the next alternating detection step.

9. The method for controlling a cryogenic valve according to claim 3, characterized in that: The alternating detection specifically includes the following steps: Step 601: preset a trigger threshold, when the auxiliary valve is closed, the processing unit sends a control instruction to the valve controller, the valve controller drives the main valve to open slowly, the processing unit obtains pressure information from the pipeline pressure module in real time, the processing unit obtains pressure information from the valve core pressure module, the processing unit divides the pressure information by the pressure information to obtain a pressure ratio, when the pressure ratio is greater than the trigger threshold, the valve controller controls the main valve to stop, records the pressure information of the valve pressure module and marks it as the critical point of the main valve, when the pressure information applied by the main valve to the valve core pressure module in the closed state is lower than the critical point of the main valve, jump to step 606, otherwise, go to the next step; Step 602: The valve controller drives the main valve to open and close once. When the main valve is closed again, the processing unit obtains the pressure information in the valve core pressure module and compares the pressure information with the pressure information when the main valve was closed last time. If the pressure information of the two times is the same, the next step is entered. If the pressure information of the two times is different, the process jumps to step 606. Step 603: the valve controller drives the main valve to close and drives the auxiliary valve to open slowly. The processing unit obtains pressure information from the pipeline pressure module in real time. The processing unit obtains pressure information from the valve core pressure module. The processing unit divides the pressure information by the pressure information to obtain a pressure ratio. When the pressure ratio is greater than the trigger threshold, the valve controller controls the auxiliary valve to stop, records the pressure information of the valve pressure module and marks it as the auxiliary valve critical point. When the pressure information applied by the auxiliary valve to the valve core pressure module in the closed state is lower than the auxiliary valve critical point, jump to step 606. Otherwise, go to the next step. Step 604: the valve controller drives the auxiliary valve to open and close once. When the auxiliary valve is closed again, the processing unit obtains the pressure information in the valve core pressure module and compares the pressure information with the pressure information when the auxiliary valve was closed last time. If the pressure information of the two times is the same, the next step is entered. If the pressure information of the two times is different, the process jumps to step 606. Step 605: If the output alternation test is qualified, stop executing the steps; Step 606: Output a warning signal.

10. The method for controlling a cryogenic valve according to claim 3, characterized in that: The logging process includes the following steps: Step 701: The processing unit saves all output warning signals, synchronizes the time when the warning signals are output, and records the operation log in chronological order; Step 702: Mark the warning signal exceeding the critical point of the main valve as an important event, mark the warning signal exceeding the critical point of the auxiliary valve as a minor event, and mark the warning signal with different pressure information before and after the main valve and the auxiliary valve are opened and closed as a general event; Step 703: The processing unit sets the order of importance of events to: important events > minor events > general events, and re-sorts the operation logs according to the order of importance of events, with important events and minor events being displayed first.

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