A gas flowmeter starting flow tester

Abstract

This invention relates to the field of gas metering equipment testing technology, and discloses a gas flow meter starting flow tester, including a tester, a gas supply mechanism fixedly connected to the outside of the tester, and a locking mechanism and an isolation mechanism arranged sequentially from near to far on the side of the gas supply mechanism away from the tester. The gas supply mechanism is used to push gas into the gas flow meter to be tested and to enable the gas flow meter to detect the starting flow. Connecting plates are fixedly connected to both sides of the gas flow meter. The locking mechanism and the isolation mechanism are used to connect the gas supply mechanism and the gas flow meter. The starting flow tester also includes an adaptive disturbance parameter calibration module, a composite drive signal generation module, a real-time flow response monitoring and starting determination module, and a starting flow calibration and locking module. This invention achieves accurate testing of the starting flow and efficient assembly and disassembly of the flow meter under test through composite signal drive and rapid locking and isolation mechanisms.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of gas metering equipment testing, in particular to a gas flow meter starting flow tester. BACKGROUND

[0002] Starting flow is a key technical index for evaluating the performance of gas flow meters, especially civil membrane gas meters, which is directly related to the metering ability and billing accuracy for small flow gas use and micro leakage. Therefore, it is of great practical significance to develop a testing device that can accurately, efficiently and repeatedly calibrate the starting flow.

[0003] In the existing technical practice, the test of the starting flow of the gas flow meter is usually carried out in the laboratory. A common method is to use a standard piston prover or a bell jar type gas flow standard device as a flow source, which is connected to the flow meter to be tested through a pipeline. During operation, the flow meter to be tested is fixed on the test bench through standard connecting parts such as flanges and bolts. Then the tester tries to drive the flow source through the control system to generate a very low and slowly increasing gas flow, while visually observing the indicating device (such as a mechanical dial or a pointer) of the flow meter to be tested. When the first identifiable movement of the indicating device is observed by visual observation, the operator records the indicating flow value of the standard flow device at that time. However, this recorded value is not the instantaneous flow at the real starting time of the flow meter, but a nominal value containing the reaction delay and subjective judgment error of the operator.

[0004] Although the existing technology can complete the test of the starting flow to some extent, there are still some deficiencies. First, there are inherent limitations in test accuracy and repeatability. The fundamental reason is that at the flow generation source end, the traditional driving device (such as a common motor or a gas cylinder) must accumulate driving force until it breaks through the maximum static friction force which is much larger than the dynamic friction force when starting from static. Once it breaks through, the accumulated energy is released instantaneously, causing the piston to produce a sudden acceleration from static to sudden acceleration, rather than smooth start. This mechanical sudden jump directly translates into an uncontrollable initial flow pulse or overshoot in the gas flow, making it impossible for the system to generate or control the gas flow stably in the range below the pulse flow. At the same time, at the flow determination end, the dial or primary indicating element of the flow meter to be tested is usually observed manually, and the standard flow value at the starting moment of the flow meter is recorded manually. This process introduces the reaction time error of the operator, resulting in a deviation between the recorded flow value and the instantaneous flow value at the real starting time of the flow meter. These factors together lead to unsatisfactory accuracy and repeatability of the test results.

[0005] Secondly, there are deficiencies in test efficiency and operation convenience. In terms of mechanical assembly of the tester, the flowmeter to be tested is usually connected and fixed through traditional flanges and bolts. This method not only requires the use of special tools such as wrenches, but also requires the operator to tighten multiple bolts in a specific order step by step and uniformly to ensure the sealing of the connection. The whole process is time-consuming and complicated to operate, especially in the case of batch testing of a large number of flowmeters, which seriously restricts the overall test efficiency. At the same time, manual operation also makes it difficult to ensure that the sealing force and centering accuracy of each installation are completely consistent, introducing uncertainty into the test results. SUMMARY

[0006] In view of the deficiencies of the prior art, the present application provides a gas flowmeter starting flow tester, which solves the problems of the prior art that the test gas flow cannot be smoothly started due to friction, the starting time is not accurately calibrated due to manual observation, and the test efficiency is low due to the complicated clamping method.

[0007] To achieve the above purpose, the present application realizes the following technical scheme: a gas flowmeter starting flow tester, comprising a tester, a gas supply mechanism fixedly connected to the outside of the tester, a locking mechanism and a partition mechanism arranged in order from near to far on the side of the gas supply mechanism away from the tester, the gas supply mechanism being used to push gas into the gas flowmeter to be tested and make the gas flowmeter detect the starting flow, both sides of the gas flowmeter being fixedly connected with connecting discs, the locking mechanism and the partition mechanism being used to connect the gas supply mechanism and one of the connecting discs, so that the gas supply mechanism and the gas flowmeter are in communication;

[0008] The starting flow tester is also provided with an adaptive disturbance parameter calibration module, a composite driving signal generation module, a flow response real-time monitoring and starting determination module, and a starting flow calibration and locking module:

[0009] The adaptive disturbance parameter calibration module is used to identify the friction characteristics of the gas supply mechanism before testing, and determine the parameters of a high-frequency periodic micro-disturbance signal used to overcome the friction characteristics accordingly;

[0010] The composite driving signal generation module is used to generate a main driving signal with a signal strength that increases linearly with time to drive the gas supply mechanism to generate a macro-increasing flow, superimpose the main driving signal and the micro-disturbance signal to form a composite driving signal to drive the gas supply mechanism;

[0011] The flow response real-time monitoring and starting determination module is used to monitor the output signal of the gas flowmeter, and generate a starting event trigger signal when the gas flowmeter first generates an effective starting signal;

[0012] The starting flow calibration and locking module is configured to, when receiving the starting event trigger signal, lock and process actual displacement data collected by a displacement sensor associated with the gas supply mechanism to calculate a starting flow.

[0013] Preferably, the gas supply mechanism comprises a connecting pipe fixedly connected to the outside of the tester, an electric telescopic rod fixedly connected inside the connecting pipe, a piston plate fixedly connected to the output end of the electric telescopic rod, a groove provided inside the connecting pipe, the piston plate being slidingly connected to the middle of the groove, an air inlet pipe penetrating through the outside of the connecting pipe, a cross-shaped block fixedly connected to the inner bottom of the air inlet pipe, a blocking ring fixedly connected to the inner top of the air inlet pipe, and a blocking ball provided between the air inlet pipe and the blocking ring.

[0014] Preferably, the tester is internally provided with a current sensor for monitoring an electric parameter for driving the electric telescopic rod; and the adaptive disturbance parameter calibration module is specifically configured to:

[0015] monitoring, by the current sensor, a change in the electric parameter before the electric telescopic rod pushes air to determine a friction characteristic, and calculating, based on the friction characteristic, an amplitude and a frequency of the micro-disturbance signal.

[0016] Preferably, the main drive signal generated by the composite drive signal generation module is a ramp signal for linearly increasing a macroscopic speed of the piston plate from zero; and the micro-disturbance signal is a high-frequency periodic signal.

[0017] Preferably, the output signal of the gas flow meter monitored by the flow response real-time monitoring and starting determination module comprises a digital pulse signal, communication protocol data, or dial reading change obtained through an optical sensor; and the effective starting signal is a change of the output signal from a static state to a first effective reading.

[0018] Preferably, the starting flow calibration and locking module is specifically configured to:

[0019] after receiving the starting event trigger signal, locking the actual displacement data of a time window containing the event moment;

[0020] performing local linear regression algorithm processing on the actual displacement data in the time window to calculate an actual speed of the piston at the moment;

[0021] and calculating the starting flow according to the actual speed and an effective cross-sectional area of the piston.

[0022] Preferably, the displacement sensor is arranged inside the connecting pipe, with a measurement end of the displacement sensor facing the piston plate for collecting actual displacement data of the piston plate.

[0023] Preferably, the locking mechanism comprises a fixed plate fixedly connected to the outer periphery of the connecting pipe, one end of the fixed plate away from the tester is fixedly connected with a limiting rod, the limiting rod is used for limiting the movement state of the partition mechanism, so that the partition mechanism only performs linear motion, the outer side of the fixed plate is fixedly connected with a connecting plate, the middle part of the connecting plate is rotatably connected with a roller shaft, the middle part of the fixed plate is rotatably connected with a wire wheel, the outer side of the wire wheel is fixedly connected with a plurality of limiting blocks, the inner part of the fixed plate is fixedly connected with a compression spring, the other end of the compression spring is fixedly connected with a clamping block, the clamping block is in contact with the limiting block, the side of the clamping block close to the compression spring is fixedly connected with a pull rod, and the pull rod is slidingly connected to the middle part of the fixed plate.

[0024] Preferably, the partition mechanism comprises a shell slidingly connected to the outer periphery of the limiting rod, a plurality of half gears are rotatably connected to the inner part of the shell, the outer side of the half gear is fixedly connected with a baffle, the side of the baffle close to the locking mechanism is fixedly connected with a rubber pad, the rubber pad is in contact with the connecting disc, a tooth ring is rotatably connected to the inner part of the shell, the outer side of the tooth ring is fixedly connected with a limiting ring, the limiting ring is rotatably connected to the inner part of the shell, the half gear and the tooth ring are meshed with each other, the side of the tooth ring away from the half gear is fixedly connected with a push rod, the push rod is slidingly connected to the middle part of the shell, the outer side of the shell is fixedly connected with a pull rope, the other end of the pull rope is fixedly connected to the outer side of the wire wheel, and the pull rope and the roller shaft are in abutment with each other.

[0025] Preferably, the connecting pipe is fixedly connected with a sealing pad at the end away from the tester, and the sealing pad is in contact with the connecting disc.

[0026] The application provides a gas flow meter starting flow tester.

[0027] 1、The application can drive the working of the gas supply mechanism by identifying the friction characteristics of the gas supply mechanism before testing and generating a composite driving signal, and the driving speed of the gas supply mechanism can determine the flow speed of the test gas flow; and by capturing the moment when the gas flow meter generates a response and immediately calibrating the actual flow at that moment, the problem of different calibration time and actual response time in the traditional testing method is solved, and the measurement accuracy of the starting flow is improved.

[0028] 2, The partition mechanism utilizes internal gear train linkage structure, so that multiple baffles can be connected to the centering disc synchronously; the locking mechanism automatically locks and quickly releases the axial locking force by the ratchet and pawl structure, the two-step operation of positioning first and then axial locking can complete the installation or replacement of the gas flowmeter in a few seconds without any tools, improve the test efficiency and reduce the complexity of operation.

[0029] 3, The gas supply mechanism of the application is composed of a combination of an air inlet pipe, a cross block, a blocking ring and a plugging ball, which constitutes a simple and reliable passive one-way air inlet valve, when the piston plate extends to exhaust, the air pressure in the pipe automatically lifts the plugging ball to close the air inlet pipe; when the piston plate retracts to inhale, the negative pressure in the pipe and the gravity of the plugging ball make it fall to open the air inlet passage, this design does not need additional driving and control unit, and completes the self-supply of the gas supply mechanism in a pure mechanical adaptive way, simplifies the system structure, reduces the failure risk and manufacturing cost. BRIEF DESCRIPTION OF DRAWINGS

[0030] Figure 1 It is a perspective view of the application;

[0031] Figure 2 It is a structural schematic view of the blocking ring of the application;

[0032] Figure 3 It is a structural schematic view of the gas supply mechanism of the application;

[0033] Figure 4 It is a structural schematic view of the gas flowmeter of the application;

[0034] Figure 5 It is a structural schematic view of the partition mechanism of the application;

[0035] Figure 6 It is a structural schematic view of the locking mechanism of the application;

[0036] Figure 7 It is Figure 6 It is an enlarged view of A in the middle.

[0037] Wherein, 1, tester; 2, gas supply mechanism; 3, gas flow meter; 4, connecting disc; 5, locking mechanism; 6, partition mechanism; 7, sealing pad; 201, connecting pipe; 202, electric telescopic rod; 203, piston plate; 204, groove; 205, air inlet pipe; 206, cross block; 207, blocking ring; 208, plugging ball; 501, fixed plate; 502, limiting rod; 503, connecting plate; 504, roller; 505, wire wheel; 506, limiting block; 507, compression spring; 508, clamping block; 509, pull rod; 601, shell; 602, half gear; 603, baffle; 604, rubber pad; 605, tooth ring; 606, limiting ring; 607, push rod; 608, pull rope. DETAILED DESCRIPTION

[0038] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the specification of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative work fall within the scope of protection of the present application.

[0039] Please refer to the drawings in the specification of the present application Figure 1 - the drawings in the specification of the present application Figure 7 The embodiment of the present application provides a gas flow meter starting flow tester, which comprises a tester 1, a gas supply mechanism 2 fixedly connected to the outer side of the tester 1, a locking mechanism 5 and a partition mechanism 6 arranged in sequence from near to far on the side of the gas supply mechanism 2 away from the tester 1, the gas supply mechanism 2 is used for pushing gas into the gas flow meter 3 to be detected and making the gas flow meter 3 detect the starting flow, and the gas flow meter 3 is fixedly connected with connecting discs 4 on both sides, the locking mechanism 5 and the partition mechanism 6 are used for connecting the gas supply mechanism 2 and one of the connecting discs 4, so that the gas supply mechanism 2 and the gas flow meter 3 are communicated.

[0040] The starting flow tester is also provided with an adaptive disturbance parameter calibration module, a composite driving signal generation module, a flow response real-time monitoring and starting determination module, and a starting flow calibration and locking module.

[0041] The adaptive disturbance parameter calibration module is used for identifying the friction characteristics of the gas supply mechanism 2 before testing, and determining the parameters of the micro-disturbance signal according to the friction characteristics.

[0042] The tester 1 is provided with a current sensor inside, which is used for monitoring the electrical parameters of the electric telescopic rod 202; the adaptive disturbance parameter calibration module is specifically used for:

[0043] The current sensor is used for monitoring the change of the electrical parameters of the electric telescopic rod 202 before pushing gas to determine the friction characteristics, and the amplitude and frequency of the micro-disturbance signal are calculated based on the friction characteristics.

[0044] The adaptive perturbation parameter calibration method provided by the application can comprise:

[0045] Before the test instrument performs the start-up flow calibration test, the input current of the electric telescopic rod 202 is controlled to start from zero and linearly increase at a preset rate, at which time the piston plate 203 of the gas supply mechanism 2 is in a static state.

[0046] The input current value of the electric telescopic rod 202 is collected and monitored in real time by the current sensor arranged inside the test instrument 1 .

[0047] The collected current data is analyzed, the critical point at which the piston plate 203 changes from a static state to a motion state is identified, and the current value corresponding to the critical point, i.e., the static friction breakthrough current , is recorded.

[0048] According to the recorded static friction breakthrough current , the parameters of the micro-perturbation signal used for subsequent composite driving signal generation, including the amplitude and the frequency , are calculated and determined.

[0049] In one specific embodiment, the start-up flow test instrument of the gas flow meter of the application comprises an adaptive perturbation parameter calibration module. The adaptive perturbation parameter calibration module is electrically connected with the current sensor inside the test instrument 1 and the controller for driving the gas supply mechanism 2. The current sensor is configured to monitor the real-time electrical parameters of the electric telescopic rod 202 in the gas supply mechanism 2.

[0050] Before performing the start-up flow test task, the controller calls the function of the adaptive perturbation parameter calibration module to perform online identification of the mechanical friction characteristics of the gas supply mechanism 2 itself.

[0051] The controller applies a ramp excitation signal to the electric telescopic rod 202, for example, a DC motor or a linear voice coil motor, so that the input current of the electric telescopic rod 202 starts from zero and linearly increases at a constant slope . In this process, the piston plate 203 remains stationary due to the constraint of static friction.

[0052] The adaptive perturbation parameter calibration module continuously obtains the real-time current of the driving source electric telescopic rod 202 through the current sensor. Since the piston plate 203 does not move, the energy of the input current is mainly used to establish a torque inside the motor to resist the static friction. When the thrust generated by the torque is just greater than the maximum static friction, the piston plate 203 will undergo a transition from static to motion. This transition will cause a sudden change in the load characteristics of the electric telescopic rod 202, thereby causing a sudden change in its input current An identifiable feature point, such as an inflection point or a tiny peak followed by a drop, is formed on the curve. The adaptive perturbation parameter calibration module accurately captures this feature point by an algorithm, such as detecting the zero or extreme point of the first or second derivative of the current signal, and records the current value corresponding to the point as the static friction breakthrough current .

[0053] The adaptive perturbation parameter calibration module calculates the parameters of the perturbation signal according to the obtained The amplitude of the perturbation signal is determined to be proportional to , and the calculation formula is:

[0054] ;

[0055] In the formula, is the amplitude of the perturbation signal; is the identified static friction breakthrough current; is a preset proportional coefficient, whose value range is 0 ≤1. In a preferred embodiment, the value of is in the interval [0.8, 1.0].

[0056] The frequency of the perturbation signal is set to a value much higher than the natural resonance frequency of the mechanical system of the gas supply mechanism 2 and the frequency value of the spectral component of the main drive signal. This setting ensures that the perturbation signal is only used to offset the nonlinear effects of friction, without producing macroscopic motion. In a specific embodiment, the frequency is set in the range of 100 Hz to 500 Hz.

[0057] Through the above steps, the adaptive perturbation parameter calibration module can accurately determine the optimal perturbation signal parameters based on the current state of the device, such as temperature, wear, lubrication state, etc., before each test, and output these parameters to the composite drive signal generation module, providing support for subsequent generation of smooth, shock-free incremental flow.

[0058] The composite drive signal generation module is used to generate a main drive signal for driving the gas supply mechanism 2 to generate an incremental flow, and to superimpose the main drive signal and the perturbation signal to form a composite drive signal for driving the gas supply mechanism 2.

[0059] The main drive signal generated by the composite drive signal generation module is a ramp signal that linearly increases the macroscopic speed of the control piston plate 203 from zero; the perturbation signal is a high-frequency periodic signal.

[0060] The composite drive signal generation method provided by the present application can include the following steps: ​

[0061] The composite driving signal generation program is started.

[0062] The main driving signal for controlling the gas supply mechanism 2 to generate macro-incremental flow is generated.

[0063] The micro-disturbance signal for offsetting the influence of friction nonlinearity is generated according to the parameter output by the adaptive disturbance parameter calibration module.

[0064] The main driving signal and the micro-disturbance signal are superimposed to form a composite driving signal.

[0065] The composite driving signal is output to the electric telescopic rod 202.

[0066] In a specific embodiment, the gas flow meter starting flow tester of the present application comprises a composite driving signal generation module. The composite driving signal generation module is electrically connected to the controller and receives parameters from the adaptive disturbance parameter calibration module, and its output is connected to the electric telescopic rod 202 of the gas supply mechanism 2. The composite driving signal generation module is used to generate an electric signal for driving the movement of the piston plate 203.

[0067] The composite driving signal generation module generates a main driving signal, which is in the form of a ramp signal, and its function is to drive the piston plate 203 to generate a macroscopically linearly increasing speed movement. If it is an electric current signal, its mathematical expression is:

[0068]

[0069] In the formula, is the current value of the main driving signal changing with time; is the slope of the ramp signal, which determines the macroscopic acceleration of the piston plate 203, and its size can be preset according to the test requirements; is time.

[0070] The composite driving signal generation module generates a micro-disturbance signal. The form of this signal is a high-frequency periodic signal, preferably a sinusoidal signal. The amplitude and the frequency of this signal are calculated and provided by the adaptive disturbance parameter calibration module in the previous stage. If it is an electric current signal, its mathematical expression is:

[0071]

[0072] In the formula, is the current value of the micro-disturbance signal changing with time; is the amplitude of the micro-disturbance signal; is the frequency of the micro-disturbance signal; is time; is the ratio of the circumference to the diameter.​​

[0073] The composite driving signal generation module superimposes the main driving signal and the micro-disturbance signal through signal addition operation to form a composite driving signal finally applied to the electric telescopic rod 202 . The mathematical expression is:

[0074] ;

[0075] In the formula, is the instantaneous current value of the final output composite driving signal at time ; is the instantaneous current value of the main driving signal at time ; is the instantaneous current value of the micro-disturbance signal at time ; is the slope of the main driving signal, which determines the size of the macro acceleration of the piston plate 203, and is a constant preset according to test requirements; is time; is the current amplitude of the micro-disturbance signal, which is determined by the adaptive disturbance parameter calibration module; is the ratio of the circumference to the diameter; is the frequency of the micro-disturbance signal, which is determined by the adaptive disturbance parameter calibration module.

[0076] The composite driving signal is output to the electric telescopic rod 202 by the driving circuit of the controller. When the composite driving signal acts on the electric telescopic rod 202, the piston plate 203 can be smoothly started from the static state and move at a stable and macroscopically linearly increasing speed, and then push the test gas flow in the connecting pipe 201 to the gas flow meter 3.

[0077] The flow response real-time monitoring and start determination module is used for monitoring the output signal of the gas flow meter 3, and generating a start event trigger signal when the gas flow meter 3 first generates an effective start signal;

[0078] The output signal of the gas flow meter 3 monitored by the flow response real-time monitoring and start determination module includes a digital pulse signal, communication protocol data or dial reading change obtained through an optical sensor; and the effective start signal is the change of the output signal from the static state to the first effective reading;

[0079] The flow response real-time monitoring and start determination method provided by the application can include the following steps:

[0080] The flow response real-time monitoring program is started at the same time when the gas supply mechanism 2 starts to generate increasing flow.

[0081] The output signal of the gas flowmeter 3 under test is continuously acquired and processed.

[0082] The output signal is analyzed to determine whether it has changed from a stationary state to a state in which the first valid reading is generated.

[0083] Immediately after the first valid reading is determined to have occurred, a priming event trigger signal is generated.

[0084] The priming event trigger signal is output to the priming flow calibration and locking module.

[0085] In one specific embodiment, the gas flowmeter priming flow tester of the present application comprises a flow response real-time monitoring and priming determination module. The flow response real-time monitoring and priming determination module comprises a sensing interface for acquiring the output signal of the gas flowmeter 3 under test, and is electrically connected to the processor of the controller, and the output end thereof is electrically connected to the priming flow calibration and locking module.

[0086] The flow response real-time monitoring and priming determination module acquires the corresponding output signal through the sensing interface according to the type of the gas flowmeter 3 under test. The output signal includes but is not limited to the following three types:

[0087] When the output signal is a digital pulse signal, the sensing interface is a pulse signal acquisition interface. The interface is connected to an external sensor, such as an optical sensor or a Hall sensor installed near the flowmeter dial. The flow response real-time monitoring and priming determination module continuously monitors the level state of the interface to capture the first complete level transition, for example, the rising edge from low to high, generated by the rotation of the internal mechanical structure of the flowmeter.

[0088] When the output signal is communication protocol data, the sensing interface is a data communication interface, such as an RS485 or CAN bus interface. The flow response real-time monitoring and priming determination module periodically sends instructions to the gas flowmeter 3 under test through the interface according to a predetermined communication protocol, such as the Modbus protocol and a time interval, to read the value of the cumulative flow register stored therein .

[0089] When the output signal is the change of the dial reading obtained by the optical sensor, the sensing interface is an image acquisition interface connected to an industrial camera facing the flowmeter dial. The flow response real-time monitoring and priming determination module acquires a real-time image sequence of the dial at a fixed frame rate .

[0090] The flow response real-time monitoring and priming determination module analyzes the acquired signal to determine the generation of a valid priming signal. Here, valid means that the change in the signal is caused by the actual metering action of the flowmeter, rather than by environmental noise, electrical interference, or slight vibration. The determination criteria depend on the type of signal:

[0091] For digital pulse signals, the flow response real-time monitoring and priming determination module determines the first captured pulse signal with pulse width and amplitude greater than the preset noise threshold as the effective priming signal.

[0092] For communication protocol data, the flow response real-time monitoring and priming determination module compares the current cumulative flow value with the initial value or the value at the last time point. When the first occurrence of the cumulative flow value is greater than the initial value, it is determined as the effective priming signal.

[0093] For dial display images, the flow response real-time monitoring and priming determination module uses image processing algorithms. First, a reference image is obtained at the start of the test . Then, for each frame of image collected, the displacement of the pointer or the word wheel relative to the reference image is calculated by feature point matching or template matching algorithms . The displacement needs to meet the following conditions to be determined as an effective priming signal:

[0094] ;

[0095] In the formula, is the displacement of the image feature calculated at the current time ; and is the preset displacement threshold, which is greater than the maximum displacement caused by device vibration or image sensor noise.

[0096] Once the flow response real-time monitoring and priming determination module determines the generation of an effective priming signal according to any of the above standards, it will immediately generate a priming event trigger signal and send it to the priming flow calibration and locking module through the internal bus or dedicated I / O pin. The trigger signal can be a certain logic level, for example, from low to high, or a software interrupt request, which is used to accurately mark the time point of the flow meter priming.

[0097] The priming flow calibration and locking module is used to lock and process the actual displacement data collected by the displacement sensor associated with the gas supply mechanism 2 to calculate the priming flow when receiving the priming event trigger signal.

[0098] The priming flow calibration and locking module is specifically used for:

[0099] After receiving the priming event trigger signal, lock the actual displacement data in a time window containing the event time;

[0100] The actual velocity of the piston at that moment is calculated by processing the actual displacement data within the time window using a local linear regression algorithm.

[0101] The starting flow rate is calculated based on the actual speed and the effective cross-sectional area of ​​the piston.

[0102] The starting flow calibration and locking method provided by this invention may include the following steps:

[0103] Receives the start event trigger signal sent by the real-time flow response monitoring and start determination module.

[0104] Based on the time of receiving the trigger signal, a time window including that time is locked, and the actual piston displacement data collected by the displacement sensor within that time window is obtained.

[0105] The actual displacement data within the time window is processed by a local linear regression algorithm to calculate the actual instantaneous velocity of the piston at the trigger moment.

[0106] The starting flow rate is calculated based on the actual instantaneous velocity and the effective cross-sectional area of ​​the piston.

[0107] In one specific embodiment, the gas flow meter starting flow tester of the present invention includes a starting flow calibration and locking module. The input terminal of the starting flow calibration and locking module is electrically connected to the flow response real-time monitoring and starting determination module and a displacement sensor disposed inside the gas supply mechanism 2. The displacement sensor, such as a high-resolution grating ruler or a linear variable differential transformer (LVDT), has its measuring end linked to the piston plate 203 to continuously collect the actual displacement data of the piston plate 203.

[0108] When the starting flow calibration and locking module receives the starting event trigger signal, it immediately records the arrival timestamp of the signal, which is recorded as the trigger time. .

[0109] The starting flow calibration and locking module is based on the trigger time. Define a time window in memory. ,in A preset half-window width, for example, 50 milliseconds, is used. The starting flow calibration and locking module extracts the set of all data points collected within this time window from the displacement sensor's data buffer. ,in Sampling time, This represents the actual displacement of the piston at that moment.

[0110] The initial momentum calibration and locking module uses a local linear regression algorithm to calculate the initial momentum. The actual instantaneous velocity of the piston at that moment This algorithm is designed for The set of data points within the time window Perform weighted linear regression to fit a local linear model .

[0111] The coefficient here is the instantaneous velocity at time . This method can effectively reduce the influence of measurement error caused by sensor noise or mechanical micro-vibration on the calculation result of velocity.

[0112] The start-up flow calibration and locking module calculates the final start-up flow value based on the actual instantaneous velocity calculated in the previous step and the effective cross-sectional area of the piston pre-calibrated and stored in the system by the following formula:

[0113] ;

[0114] In the formula, is the calculated start-up flow value; is the actual instantaneous velocity of the piston at the triggering time ; and is the effective cross-sectional area of the piston plate 203 in the gas supply mechanism 2, which is a known constant.

[0115] The calculated start-up flow value can then be displayed on the human-computer interaction interface of the tester 1 or stored in the test report. This whole set of processes ensures that the calibration of the start-up flow is based on the accurate time when the flowmeter responds and the actual flow at that time, thereby obtaining objective and repeatable measurement results.

[0116] Please refer to the attached Figure 2 and the attached Figure 3 ​In a preferred embodiment of the present application, the gas supply mechanism 2 comprises a connecting pipe 201 fixedly connected to the outside of the tester 1, an electric telescopic rod 202 fixedly connected inside the connecting pipe 201, a piston plate 203 fixedly connected to the output end of the electric telescopic rod 202, a groove 204 provided inside the connecting pipe 201, the piston plate 203 being slidingly connected to the middle part of the groove 204, one end of the connecting pipe 201 being connected to the outside of the tester 1 and the other end being connected to the inlet of the gas flow meter 3 to be tested, the gas in the connecting pipe 201 being sent into the gas flow meter 3 to be tested by driving the electric telescopic rod 202 to make the piston plate 203 extend, a gas inlet pipe 205 penetrating through the outside of the connecting pipe 201, a cross-shaped stop block 206 fixedly connected to the inner bottom of the gas inlet pipe 205, a stop ring 207 fixedly connected to the inner top of the gas inlet pipe 205, and a blocking ball 208 provided between the gas inlet pipe 205 and the stop ring 207, the working process of the gas supply mechanism 2 comprising one exhaust stroke and one suction stroke.

[0117] In the exhaust stroke, the electric telescopic rod 202 drives the piston plate 203 to move towards the gas flow meter 3 to be tested, the movement of the piston plate 203 compresses the gas inside the connecting pipe 201, resulting in the increase of the gas pressure in the pipe, the increased gas pressure acts on the lower surface of the blocking ball 208 to push it upwards until it tightly adheres to the lower surface of the stop ring 207, thereby completely closing the gas inlet pipe 205, at this time, the gas in the connecting pipe 201 is effectively pushed to the gas flow meter 3 to be tested.

[0118] In the suction stroke, the electric telescopic rod 202 drives the piston plate 203 to move reversely, i.e. away from the gas flow meter 3 to be tested, the reverse movement of the piston plate 203 increases the volume inside the connecting pipe 201, forming a negative pressure, under the action of the negative pressure and the gravity of the blocking ball 208 itself, the blocking ball 208 is separated from the stop ring 207 and falls onto the cross-shaped stop block 206, thereby opening the gas inlet pipe 205, at this time, the gas is sucked into the connecting pipe 201 through the opened gas inlet pipe 205, completing a suction action.

[0119] Please refer to the accompanying drawings Figure 2 and the accompanying drawings Figure 3 In a preferred embodiment of the present application, the displacement sensor is provided inside the connecting pipe 201, the measurement end of the displacement sensor facing the piston plate 203, for collecting the actual displacement data of the piston plate 203.

[0120] In a specific embodiment, the displacement sensor is a grating ruler. The ruler body of the grating ruler is fixedly connected to the inner wall of the connecting pipe 201 in parallel with the movement direction of the piston plate 203. The reading head of the grating ruler is fixedly connected to the piston plate 203 and slides along the ruler body together with the piston plate 203. The reading head continuously reads the scale lines on the ruler body during the sliding process and generates an electrical signal proportional to the displacement, for example, a quadrature pulse signal.

[0121] The grating ruler described in the present application is the prior art which will not be described in detail.

[0122] Please refer to the accompanying drawings Figure 5 , the accompanying drawings Figure 6 and the accompanying drawings Figure 7 In a preferred embodiment of the present application, the locking mechanism 5 comprises a fixed plate 501 fixedly connected to the outer periphery of the connecting pipe 201, the end of the fixed plate 501 away from the tester 1 is fixedly connected to a limiting rod 502, the limiting rod 502 is used to limit the movement state of the partition mechanism 6, so that the partition mechanism 6 only performs linear motion, the outer side of the fixed plate 501 is fixedly connected to a connecting plate 503, the middle part of the connecting plate 503 is rotatably connected to a roller shaft 504, the middle part of the fixed plate 501 is rotatably connected to a wire wheel 505, the outer side of the wire wheel 505 is fixedly connected to a plurality of limiting blocks 506, the inner part of the fixed plate 501 is fixedly connected to a compression spring 507, the other end of the compression spring 507 is fixedly connected to a clamping block 508, the clamping block 508 is in contact with the limiting block 506, the side of the clamping block 508 close to the compression spring 507 is fixedly connected to a pull rod 509, the pull rod 509 is slidingly connected to the middle part of the fixed plate 501.

[0123] The partition mechanism 6 comprises a shell 601 slidingly connected to the outer periphery of the limiting rod 502, the inner part of the shell 601 is rotatably connected to a plurality of half gears 602, the outer side of the half gears 602 is fixedly connected to baffles 603, the side of the baffles 603 close to the locking mechanism 5 is fixedly connected to rubber pads 604, the rubber pads 604 are in contact with the connecting disc 4, the inner part of the shell 601 is rotatably connected to a tooth ring 605, the outer side of the tooth ring 605 is fixedly connected to a limiting ring 606, the limiting ring 606 is rotatably connected to the inner part of the shell 601, the half gears 602 and the tooth ring 605 are meshed with each other, the side of the tooth ring 605 away from the half gears 602 is fixedly connected to a push rod 607, the push rod 607 is slidingly connected to the middle part of the shell 601, the push rod 607 is used to drive the tooth ring 605 to rotate when the shell 601 slides, the outer side of the shell 601 is fixedly connected to a pull rope 608, the other end of the pull rope 608 is fixedly connected to the outer side of the wire wheel 505, and the pull rope 608 and the roller shaft 504 abut each other.

[0124] Specifically: when partitioning one of the connecting discs 4, the operator pushes the push rod 607 forward to drive the tooth ring 605 to rotate, which converts into the rotary motion of the half gears 602, so that the inner side of the plurality of baffles 603 fixedly connected to the driven half gears 602 swings until the rubber pads 604 at the ends thereof move to between one of the connecting discs 4 and the connecting pipe 201.

[0125] After the partition operation is executed, the operator rotates the wire wheel 505, and when the wire wheel 505 rotates in the tightening direction, the limiting block 506 will press against the inclined surface of the clamping block 508, so that the clamping block 508 retreats against the elastic force of the compression spring 507; after passing the tooth top, the clamping block 508 is reset under the action of the elastic element compression spring 507 and is clamped into the next tooth valley, and this process is cyclically performed, so that the wire wheel 505 rotates in one direction and winds the pull rope 608, and when the pull rope 608 is wound, the rubber pad 604 can be attached and drives the connecting disc 4 to be close to the connecting pipe 201, so that the baffle 603 and the rubber pad 604 extrude the connecting disc 4, and the connecting disc 4 contacts and extrudes the sealing gasket 7 and the connecting pipe 201 during the extrusion process, thereby forming a reliable airtight connection.

[0126] When the unlocking operation is performed, the operator pulls the pull rod 509 outward, the pull rod 509 drives the clamping block 508 to retreat against the elastic force of the compression spring 507, so that the clamping end is completely separated from the meshing range of the limiting block 506, at this time, the locking of the wire wheel 505 is released, and the shell 601 can be pulled to separate the connecting disc 4 and the connecting pipe 201, thereby realizing the quick release of the entire partition mechanism 6, facilitating the removal or replacement of the gas flow meter 3 to be tested, and improving the operation efficiency.

[0127] Please refer to the accompanying drawings Figure 3 In a preferred embodiment of the present application, the connecting pipe 201 is fixedly connected with the sealing gasket 7 away from the tester 1, and the sealing gasket 7 contacts the connecting disc 4, and the sealing property between the connecting disc 4 and the connecting pipe 201 after connection can be enhanced by adding the sealing gasket 7, so as to avoid gas leakage.

[0128] Please refer to the accompanying drawings Figure 1 In a preferred embodiment of the present application, when it is necessary to test flammable gas or toxic and harmful gas, the external gas pipeline is connected through the flange plate, so as to connect the external gas pipeline with the gas inlet pipe 205, and after connection, a blocking device is driven to block the exhaust end of the gas flow meter 3, and at the same time, the flammable gas or toxic and harmful gas is recycled through the gas discharge pipe, so as to avoid leakage of the flammable gas or toxic and harmful gas.

[0129] The blocking device is composed of a cylinder and a blocking block, and the cylinder can contact the blocking block with the exhaust end of the gas flow meter 3 and close the exhaust end when driven.

[0130] Working principle: before use, first hand gas flowmeter 3 and one of the connecting disc 4 through the shell 601, by pushing the push rod 607 in the shell 601 directly above, make gear ring 605 driven half gear 602 rotation, in half gear 602 rotation makes baffle 603 and rubber pad 604 swing out, and cover connecting disc 4 make connecting disc 4 can't fall off, this time through the rotation of the line wheel 505 and in the connecting plate 503 and the limit of the roller 504 will be pulled rope 608 winding, in the rope 608 is wound at the same time, through the limit of the rod 502 limit makes the shell 601 continuously close to the fixed plate 501 and makes the rubber pad 604, connecting disc 4 and sealing pad 7 close contact, in the line wheel 505 rotation will be on the block 508 tilt surface extrusion, make the block 508 force up and compress the compression spring 507, when the block 508 is not extruded, the compression spring 507 releases the compression force and resets the block 508 to limit the line wheel 505, so as to complete the installation operation of the gas flowmeter 3;

[0131] Secondly, by driving the electric telescopic rod 202 makes the piston plate 203 forward movement, push the gas in the connecting pipe 201 out, at the same time the gas will blow the blocking ball 208 up, through the blocking ring 207 limit of the blocking ball 208 can close the air inlet pipe 205, so that the gas into the gas flowmeter 3, when the electric telescopic rod 202 is driven to retract the piston plate 203, the blocking ball 208 falls under pressure to open the air inlet pipe 205, at this time can be through the air inlet pipe 205 and the suction force of the piston plate 203 to suck the gas into;

[0132] Before the test starts, first of all, through the adaptive calibration technology to generate a small vibration signal, to ensure that the follow-up can produce smooth and no impact of the small flow; then, the system through a slow incremental main signal superimposed a small perturbation signal, to promote the piston to produce a from zero start, stable growth of extremely small gas flow into the flowmeter to be tested, at the same time, the real-time monitoring module continues to monitor the gas flowmeter 3, when the flowmeter first produces effective read such as sending the first pulse or dial jump, will immediately send a trigger signal, the signal will start the calibration and locking module, so that it immediately locks the high precision displacement sensor data, and through the analysis and calculation of the piston at the moment of the accurate speed, and finally according to the formula flow = speed x piston area, conversion of accurate start flow value;

[0133] When the end, by pulling the pull rod 509 can be raised to collect the block 508, at the same time pull the partition mechanism 6 or gas flowmeter 3 can be separated from the connecting disc 4 and sealing pad 7, at this time to remove the extrusion of the connecting disc 4 and reverse push the push rod 607 can be collected baffle 603 and rubber pad 604, remove the blocking of the connecting disc 4, can conveniently take down or replace the gas flowmeter 3;

[0134] When it is necessary to test the combustible gas or the toxic and harmful gas, the external gas pipeline is connected through the flange plate, and the cylinder is driven to push the blocking block to the exhaust end of the gas flow meter 3 and close the exhaust end. At this time, the gas flow meter 3 detects the inhaled combustible gas or toxic and harmful gas through the gas supply mechanism 2, and recycles the combustible gas or toxic and harmful gas under the action of the gas discharge pipe.

[0135] While embodiments of the application have been shown and described, it is to be understood that the embodiments described are merely divergences of the principles and spirit of the application and that numerous modifications, changes, replacements, and variations can be made thereto by those skilled in the art without departing from the principles and spirit of the application, and the scope of the application is defined by the appended claims and their equivalents.

Claims

1. A gas flow meter commissioning flow tester comprising a tester (1), characterized in that, The outer side of the tester (1) is fixedly connected with a gas supply mechanism (2), the side far from the tester (1) of the gas supply mechanism (2) is sequentially provided with a locking mechanism (5) and a partition mechanism (6) from near to far, the gas supply mechanism (2) is used for pushing gas into a gas flowmeter (3) to be detected and making the gas flowmeter (3) detect an initial flow, both sides of the gas flowmeter (3) are fixedly connected with connecting discs (4), the locking mechanism (5) and the partition mechanism (6) are used for connecting the gas supply mechanism (2) and one of the connecting discs (4), so that the gas supply mechanism (2) and the gas flowmeter (3) are communicated; The initial flow tester is also provided with a self-adaptive disturbance parameter calibration module, a composite driving signal generation module, a flow response real-time monitoring and initial determination module and an initial flow calibration and locking module: The self-adaptive disturbance parameter calibration module is used for identifying the friction characteristics of the gas supply mechanism (2) before testing, and determining the parameters of a high-frequency periodic micro-disturbance signal used for overcoming the friction characteristics according to the friction characteristics; The composite driving signal generation module is used for generating a main driving signal with linearly increasing signal strength over time to drive the gas supply mechanism (2) to generate macro-incremental flow, superimposing the main driving signal and the micro-disturbance signal to form a composite driving signal to drive the gas supply mechanism (2); The flow response real-time monitoring and initial determination module is used for monitoring the output signal of the gas flowmeter (3), and generating an initial event trigger signal when the gas flowmeter (3) first generates an effective start signal; The initial flow calibration and locking module is used for locking and processing the actual displacement data collected by the displacement sensor associated with the gas supply mechanism (2) when the initial event trigger signal is received, so as to calculate the initial flow; The gas supply mechanism (2) comprises a connecting pipe (201), the connecting pipe (201) is fixedly connected to the outer side of the tester (1), an electric telescopic rod (202) is fixedly connected to the inside of the connecting pipe (201), the output end of the electric telescopic rod (202) is fixedly connected with a piston plate (203), a recess (204) is arranged in the connecting pipe (201), the piston plate (203) is slidingly connected to the middle part of the recess (204), the piston plate (203) and the inner wall of the recess (204) are in close contact, an air inlet pipe (205) penetrates through the outer side of the connecting pipe (201), a cross-shaped stop block (206) is fixedly connected to the inner bottom of the air inlet pipe (205), a stop ring (207) is fixedly connected to the inner top of the air inlet pipe (205), a plugging ball (208) is arranged between the cross-shaped stop block (206) and the stop ring (207), the plugging ball (208) can be in close contact with the inner wall of the stop ring (207) under the driving of gas to make the air inlet pipe (205) in a closed state; The tester (1) is provided with a current sensor inside, which is used for monitoring the electric parameters for driving the electric telescopic rod (202); the self-adaptive disturbance parameter calibration module is specifically used for: The electric parameter change before the electric telescopic rod (202) pushes gas is monitored by the current sensor to determine the friction characteristic, and the amplitude and frequency of the micro-disturbance signal are calculated based on the friction characteristic; The main drive signal generated by the composite drive signal generation module is a ramp signal for linearly increasing the macroscopic speed of the piston plate (203) from zero; and the micro-disturbance signal is a high-frequency periodic signal. The initial flow calibration and locking module is specifically used for: locking the actual displacement data of a time window containing the event moment after receiving the initial event trigger signal; calculating the actual speed of the piston at the moment by performing local linear regression algorithm processing on the actual displacement data in the time window; and calculating the initial flow according to the actual speed and the effective cross-sectional area of the piston.

2. The gas flow meter proving tester of claim 1, wherein, The output signal of the gas flowmeter (3) monitored by the flow response real-time monitoring and initial determination module includes a digital pulse signal, communication protocol data, or dial number change obtained through an optical sensor; and the effective start signal is the change of the output signal from a static state to the first effective reading.

3. The gas flowmeter proving device of claim 1 wherein, The displacement sensor is arranged inside the connecting pipe (201), and the measurement end of the displacement sensor faces the piston plate (203) and is used for collecting the actual displacement data of the piston plate (203).

4. The gas flow meter proving device of claim 1, wherein, The locking mechanism (5) includes a fixed plate (501) fixedly connected to the outer periphery of the connecting pipe (201), one end of the fixed plate (501) away from the tester (1) is fixedly connected with a limiting rod (502), the limiting rod (502) is used for limiting the movement state of the partition mechanism (6), so that the partition mechanism (6) only performs linear motion, the outer side of the fixed plate (501) is fixedly connected with a connecting plate (503), the middle part of the connecting plate (503) is rotatably connected with a roller (504), the middle part of the fixed plate (501) is rotatably connected with a wire wheel (505), the outer side of the wire wheel (505) is fixedly connected with a plurality of limiting blocks (506), the inside of the fixed plate (501) is fixedly connected with a compression spring (507), the other end of the compression spring (507) is fixedly connected with a clamping block (508), the clamping block (508) is in contact with the limiting block (506), one side of the clamping block (508) close to the compression spring (507) is fixedly connected with a pull rod (509), and the pull rod (509) is slidingly connected to the middle part of the fixed plate (501).

5. A gas flowmeter proving apparatus according to claim 4, wherein, The partition mechanism (6) includes a shell (601), the shell (601) is connected in the outer periphery of the limiting rod (502) slidingly, a plurality of half gears (602) are rotatably connected in the shell (601), the outer side of the half gear (602) is fixedly connected with a baffle (603), the side of the baffle (603) close to the locking mechanism (5) is fixedly connected with a rubber pad (604), the rubber pad (604) is in contact with the connecting disc (4), a tooth ring (605) is rotatably connected in the shell (601), the outer side of the tooth ring (605) is fixedly connected with a limiting ring (606), the limiting ring (606) is rotatably connected in the shell (601), the half gear (602) and the tooth ring (605) are engaged with each other, the side, away from the half gear (602), of the tooth ring (605) is fixedly connected with a push rod (607), the push rod (607) is slidingly connected in the middle of the shell (601), the outer side of the shell (601) is fixedly connected with a pull rope (608), the other end of the pull rope (608) is fixedly connected with the outer side of the thread wheel (505), and the pull rope (608) and the roller shaft (504) abut each other.

6. A gas flowmeter proving apparatus according to claim 5, wherein, The connecting pipe (201) is fixedly connected with a sealing pad (7) at one end, away from the tester (1), the sealing pad (7) is in contact with the connecting disc (4).

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