Glass fiber reinforced plastic pipe pressure test method and device based on double-speed boost arrangement

Abstract

The application belongs to the technical field of pressure test control, and particularly relates to a glass steel pipe pressure test method and device based on double-speed boosting arrangement. The method comprises the following steps: obtaining a target test pressure, a switching pressure and an allowable pressure range, rising to the switching pressure at a first boosting speed, determining a pressure injection benchmark by a pressure increment and an actual injection amount, and determining a transient characteristic by a free pressure response after stopping injection; generating an injection instruction group containing an injection proportion and a time interval according to a difference between the target test pressure and a current pressure, the pressure injection benchmark and the transient characteristic, adjusting an injection amount in the same proportion according to a boosting response that has been executed; executing the injection instruction group at a second boosting speed lower than the first boosting speed, updating the pressure injection benchmark and the transient characteristic according to a boosting response, and generating a next injection instruction group until entering a pressure test timing and reducing to zero after entering the allowable pressure range. The application continuously adjusts an injection amount and an injection time sequence in a stage close to the target test pressure according to an actual boosting response.

Description

Technical Field

[0001] This invention relates to the field of pressure resistance test control technology, specifically to a pressure resistance test method and apparatus for fiberglass pipes based on a dual-speed pressure increase program. Background Technology

[0002] After manufacturing, fiberglass pipes typically undergo a pressure test to verify the pressure-bearing capacity of the pipe body, connections, and seals under specified pressure conditions. Current pressure tests usually involve controlling the injection equipment according to a pre-set pressure increase rate or segmented pressure values, causing the test pressure to rise continuously or gradually approach the target test pressure, and starting the pressure test timing once the target test pressure is reached.

[0003] This type of control method typically uses the pressurization rate, single injection volume, or pressure increment as fixed parameters, rarely utilizing the real-time response relationship between pressure changes and injection volume during actual pressurization. The fiberglass pipe, test liquid, connecting pipelines, and sealing structure together constitute a pressure system with elastic deformation and liquid compression effects. As the test pressure increases, the pressure increment corresponding to a unit injection volume may change. If fixed pressurization parameters are still applied when approaching the target test pressure, the injection volume applicable to the previous pressure range may produce different pressure responses in the subsequent pressure range, making it difficult to precisely control the pressure increment near the target test pressure. After injection stops, the test pressure may also experience short-term oscillations and attenuation due to liquid inertia, pipe elastic deformation, and pressure system response. Fixed time intervals or continuous injection methods do not utilize this transient change to determine the timing of subsequent injections, easily causing adjacent injection actions to superimpose with existing pressure oscillations. Some test controls also directly enter the pressure withstand timing after instantaneously reaching the set pressure, failing to distinguish between the transient pressurization state and the stable pressure state.

[0004] Therefore, existing technologies need to address how to organize the pressurization process by combining the actual pressure-injection response and the transient changes after stopping injection during the phase approaching the target test pressure, and how to ensure that subsequent pressurization parameters can be continuously corrected as the pressurization response has been executed. Summary of the Invention

[0005] This invention provides a method and apparatus for pressure resistance testing of fiberglass pipes based on dual-speed pressure ramping, which at least solves the problem of how to dynamically ramp up the injection action by combining the pressure injection response and the transient characteristics of free pressure during the process of fiberglass pipe approaching the target test pressure, and how to control the pressure ramping to the allowable pressure range in a closed loop.

[0006] In a first aspect, the present invention provides a pressure resistance test method for fiberglass pipes based on a dual-speed pressure-increasing arrangement, the method comprising: Obtain the target test pressure, switching pressure, and allowable pressure range; increase the pressure to the switching pressure at the first pressurization rate; determine the pressure injection reference by the pressure increment and the actual injection volume; stop injection; and determine the transient characteristics by the free pressure response. The injection command set containing the injection ratio and time interval is generated from the difference between the target test pressure and the current pressure, the pressure injection reference and transient characteristics. The injection volume of the injection command set is adjusted proportionally according to the executed pressure increase response while maintaining the time interval. The injection command group is executed at a second pressure increase rate lower than the first pressure increase rate. The pressure injection reference and transient characteristics are updated by the pressure increase response, and the next injection command group is generated until the current pressure reaches the allowable pressure range. After the current pressure reaches the allowable pressure range, the pressure is tested and the pressure is reduced to zero.

[0007] In one possible implementation, the switching pressure is determined according to a preset ratio of the target test pressure, and the allowable pressure range is determined by the target test pressure and the allowable pressure deviation.

[0008] In one possible implementation, determining the pressure injection reference based on the pressure increment and the actual injection volume includes: during the process of increasing the pressure to the switching pressure at a first pressurization rate, determining multiple pressure windows within a preset pressure range before the switching pressure, obtaining the pressure increment and the actual injection volume within each pressure window, and determining the pressure injection reference based on the pressure increment and the actual injection volume within each pressure window.

[0009] In one possible implementation, the pressure injection benchmark is determined based on the pressure increment and actual injection volume within each pressure window, including: determining the window injection volume parameter corresponding to each pressure window based on the proportional relationship between the actual injection volume and the pressure increment within each pressure window; selecting a preset number of pressure windows from high to low according to the pressure upper limit of each pressure window, and determining the pressure injection benchmark based on the window injection volume parameter corresponding to the selected pressure windows.

[0010] In one possible implementation, the injection is stopped, and transient characteristics are determined by the free pressure response, including: acquiring a pressure sequence after the injection is stopped; determining a stable pressure and two consecutive pressure peaks located on the same side of the stable pressure from the pressure sequence; determining the pressure oscillation period based on the occurrence time of the two pressure peaks; determining the pressure decay characteristics based on the deviation of the two pressure peaks from the stable pressure; and using the pressure oscillation period and pressure decay characteristics as transient characteristics.

[0011] In one possible implementation, an injection command group is generated from the difference between the target test pressure and the current pressure, the pressure injection reference, and transient characteristics. This includes: determining the difference between the target test pressure and the current pressure as a pressure margin; determining the target pressure increment of the current booster unit based on the pressure margin; determining the total injection volume based on the target pressure increment and the pressure injection reference; allocating the total injection volume into multiple sub-injection volumes according to the transient characteristics; and determining the time interval between injection actions corresponding to adjacent sub-injection volumes to obtain the injection command group.

[0012] In one possible implementation, the transient characteristics include pressure decay characteristics and pressure oscillation period; the total injection volume is allocated into multiple sub-injection volumes according to the transient characteristics, and the time interval between injection actions corresponding to adjacent sub-injection volumes is determined, including: determining the volume ratio relationship between each sub-injection volume according to the pressure decay characteristics, determining the time interval between injection actions corresponding to adjacent sub-injection volumes according to the pressure oscillation period, and generating an injection command group based on the volume ratio relationship and the time interval.

[0013] In one possible implementation, adjusting the injection volume of the injection command group proportionally according to the executed pressure boosting response includes: determining the pressure increase relationship between the actual pressure increment and the actual injection volume based on the actual pressure increment and the actual injection volume in the executed pressure boosting response; determining the expected pressure increment based on the pressure increase relationship and the total injection volume; determining the injection adjustment parameters for proportionally adjusting each sub-injection volume based on the target pressure increment and the expected pressure increment; and adjusting each sub-injection volume proportionally according to the injection adjustment parameters while keeping the time interval constant.

[0014] In one possible implementation, updating the pressure injection reference and transient characteristics based on the pressure boost response and generating the next injection command group includes: after the injection command group is executed, acquiring the stable pressure, actual injection volume, and free pressure response before and after the execution of the injection command group, and determining the stable pressure increment based on the stable pressure before and after execution; updating the pressure injection reference based on the stable pressure increment and the actual injection volume, updating the transient characteristics based on the free pressure response, and generating the next injection command group based on the updated pressure injection reference and the updated transient characteristics.

[0015] Secondly, the present invention provides a pressure resistance testing device for fiberglass pipes based on a dual-speed pressure increase arrangement, used to implement a pressure resistance testing method for fiberglass pipes based on a dual-speed pressure increase arrangement. The device includes: The pressure boosting and base-building module is used to obtain the target test pressure, switching pressure and allowable pressure range, increase the pressure to the switching pressure at the first pressure boosting rate, determine the pressure injection base by the pressure increment and the actual injection volume, stop the injection, and determine the transient characteristics by the free pressure response. The instruction orchestration module is used to generate an injection instruction group containing the injection ratio and time interval based on the difference between the target test pressure and the current pressure, the pressure injection reference, and transient characteristics. The injection volume of the injection instruction group is adjusted proportionally according to the executed pressure increase response while maintaining the time interval. The pressure-resistant execution module is used to execute the injection command group at a second pressure-increasing speed lower than the first pressure-increasing speed. The pressure injection reference and transient characteristics are updated by the pressure-increasing response and the next injection command group is generated until the current pressure reaches the allowable pressure range. After the current pressure reaches the allowable pressure range, the pressure-resistant timing is started and the pressure is reduced to zero.

[0016] Compared with the prior art, the advantages and beneficial effects of the present invention are as follows: By determining the pressure injection reference using the pressure increment and actual injection volume during the pressure increase phase corresponding to the first pressure increase rate, the actual pressure increase relationship between the current FRP pipe, test liquid, and pressure system is quantified, ensuring that the injection volume after pressure switching no longer relies solely on fixed empirical parameters. By stopping injection at the pressure switching point and determining transient characteristics from the free pressure response, the pressure oscillations and decay states after injection cessation can be used for the arrangement of subsequent injection command groups. By combining the difference between the target test pressure and the current pressure, the pressure injection reference, and transient characteristics to generate injection command groups containing injection ratios and time intervals, the injection scale, the proportional relationship between each injection volume, and the time relationship between injection actions are determined within the same control chain. By adjusting the injection volume proportionally based on the executed pressure increase response while maintaining the time interval, each sub-injection volume can be scaled as a whole according to the same injection adjustment parameters, while keeping the time interval determined by the transient characteristics unchanged. By continuously updating the pressure injection reference and transient characteristics during the second pressurization rate stage, the subsequent injection command group can be corrected according to the actual pressurization response, and after entering the allowable pressure range, it switches to pressure resistance timing and depressurization to zero, forming a continuous closed-loop pressure resistance test control process. Attached Figure Description

[0017] Figure 1 This is a schematic flowchart of the pressure resistance test method for FRP pipes based on dual-speed pressure increase arrangement in an embodiment of the present invention; Figure 2 This is a diagram showing the construction of the pressure window and pressure injection reference in an embodiment of the present invention; Figure 3 This is a diagram showing the free pressure response and transient feature extraction at the pressure switching point in an embodiment of the present invention; Figure 4 This is a diagram showing the volume ratio and time interval arrangement of the injection command group in an embodiment of the present invention; Figure 5 This is a diagram showing the closed-loop update and stable pressure change of the injection command group in an embodiment of the present invention; Figure 6This is a diagram showing the pressure withstand time and pressure reduction to zero process within the allowable pressure range in this embodiment of the invention; Figure 7 This is a schematic diagram of the pressure resistance test device for fiberglass pipes based on dual-speed pressure increase arrangement in an embodiment of the present invention. Detailed Implementation

[0018] The embodiments of the present invention will be described below with reference to the accompanying drawings. These embodiments are used to illustrate the technical solutions of the present invention and are not intended to limit the scope of protection of the present invention. Those skilled in the art can make adaptive adjustments to the relevant processing order, data structure, or parameter values ​​without changing the technical concept of the present invention.

[0019] In this embodiment, the dual-speed pressurization program uses the fiberglass pipe to be tested for pressure resistance as the processing object. The pressure test system receives the target test pressure, switching pressure, and allowable pressure range, and simultaneously acquires the current pressure, pressure increment, actual injection volume, and free pressure response after injection stops during the pressurization process. The fiberglass pipe, the test liquid, and the pressure test system connected to the fiberglass pipe together form the pressure response environment corresponding to the pressurization process. The first pressurization speed is used to advance the current pressure to the switching pressure, and the pressure increment and actual injection volume obtained in this stage form a pressure injection reference. After reaching the switching pressure, injection stops, and the transient characteristics are determined by the free pressure response. The pressure injection reference and transient characteristics serve as the processing basis for the second pressurization speed stage. Together with the pressure margin between the target test pressure and the current pressure, they are used to generate an injection command set, which is continuously updated by subsequent pressurization responses until the current pressure enters the allowable pressure range.

[0020] like Figure 1 As shown, a pressure resistance test method for fiberglass pipes based on dual-speed pressure increase arrangement includes the following processing steps.

[0021] The pressure testing system receives the target test pressure for this FRP pipe pressure test and obtains the switching pressure and allowable pressure range. At the start of the test, the pressure testing system continuously records the test pressure and the actual injection volume, pushes the test pressure up to the switching pressure at the first pressurization rate, and uses the relationship between the pressure increment formed during the pressurization process and the actual injection volume to form a pressure injection reference.

[0022] Once the switching pressure is reached, injection is stopped, and the free pressure response, formed by the change of test pressure over time, is continuously acquired. Transient characteristics are determined from the free pressure response. The pressure injection baseline and transient characteristics are jointly transmitted to the subsequent injection command group generation stage, serving as the basis for determining the injection volume and time interval, respectively.

[0023] In one embodiment, the switching pressure is determined according to a preset ratio of the target test pressure. The preset ratio is set according to the need for pressure surge control when the FRP pipe approaches the target test pressure, so that the pressure surge stage corresponding to the first pressure surge speed covers the main pressure surge range before the target test pressure, while reserving pressure space for liquid injection arrangement using the second pressure surge speed between the switching pressure and the target test pressure.

[0024] In one feasible setup, the preset ratio is 0.75, meaning the switching pressure is 75% of the target test pressure. When the specifications of the FRP pipe, test requirements, or the pressure control capability of the pressure resistance test system change, the preset ratio can be reset without altering the dual-speed pressurization logic. The preset ratio remains unchanged after the start of a single pressure resistance test on the same FRP pipe, ensuring that the first and second pressurization speeds are always separated by the same switching pressure.

[0025] The permissible pressure range is determined centered on the target test pressure and in conjunction with the permissible pressure deviation. The permissible pressure deviation can be jointly determined by the test standard adopted for this pressure resistance test, the test requirements for FRP pipes, and the pressure control accuracy of the pressure resistance test system. The permissible pressure deviation remains consistent throughout a single pressure resistance test and is used to establish a fixed pressure boundary for determining whether the target test pressure has been reached.

[0026] Before the pressure test system starts, the target test pressure, switching pressure, and allowable pressure range are programmed, and the numerical relationship between these three values ​​is verified to ensure that the switching pressure is below the lower limit of the allowable pressure range and that the target test pressure is within the allowable pressure range. If the verification passes, the system is allowed to proceed to the pressure ramping stage corresponding to the first ramping speed. If the numerical relationship is not satisfied, pressure ramping is not initiated, and the switching pressure or allowable pressure deviation is redefined. Therefore, the switching pressure serves as the pressure boundary between the first and second ramping speeds, and the allowable pressure range serves as the basis for determining whether subsequent injection commands should stop further pressure ramping and begin the pressure test timing.

[0027] In one embodiment, during the process of increasing the test pressure to the switching pressure at a first pressurization rate, the pressure testing system selects a preset pressure range before the switching pressure to form a pressure injection reference. The lower limit of the preset pressure range is higher than the initial test pressure, and the upper limit is not higher than the switching pressure. Its range is determined as needed to avoid large response fluctuations during the initial pressurization phase and to cover the pressurization segment that reflects the relationship between the current pressure increment and the actual injection volume when approaching the switching pressure.

[0028] In one feasible setup, the preset pressure range can be located between 55% and 75% of the target test pressure. The pressure resistance testing system divides the preset pressure range into multiple pressure windows in a continuously increasing direction. The pressure windows are arranged consecutively without overlap, and the width of the pressure window is determined based on the pressure acquisition resolution, the injection volume measurement resolution, and the number of pressure windows that can be formed within the preset pressure range.

[0029] When the test pressure enters a pressure window, the initial test pressure and cumulative injection volume are recorded. When the test pressure leaves the pressure window, the test pressure and cumulative injection volume are also recorded. The difference between the two test pressures is taken as the pressure increment for that pressure window, and the difference between the two cumulative injection volumes is taken as the actual injection volume for that pressure window. After completing the data recording for one pressure window, the first pressurization rate is maintained, and subsequent pressure windows are processed in the same way until the test pressure reaches the switching pressure.

[0030] If a pressure window experiences missing pressure data, continuous inflow of liquid, or a pressure increment not greater than zero, that pressure window will not be used to determine the pressure injection baseline, and the remaining valid pressure windows will be retained. After acquiring data for the preset pressure range, the pressure test system uses the pressure increment and actual inflow of liquid from each valid pressure window to determine the pressure injection baseline, and then transmits the pressure injection baseline to the injection command group generation stage after the pressure switch.

[0031] In one embodiment, the window injection volume parameter corresponding to each pressure window is used to characterize the actual injection volume required to form a unit pressure increment within that pressure window. The pressure test system reads the pressure increment and actual injection volume of a pressure window, and calculates the window injection volume parameter according to the ratio of the actual injection volume to the pressure increment.

[0032] in, For the first Window injection volume parameters for each pressure window. For the first The actual injection volume for each pressure window For the first Pressure increment per pressure window This is the sequence number of the pressure window. This calculation is performed only on pressure windows where the pressure increment is greater than zero and the actual injection volume is fully recorded.

[0033] After obtaining the injection volume parameters for each pressure window, the pressure test system sorts the pressure windows from highest to lowest pressure upper limit and selects a preset number of pressure windows from the sorting results. The preset number is determined based on the number of effective pressure windows that can be stably obtained within the preset pressure range and the degree of fluctuation of the injection volume parameters. In one feasible setting, three pressure windows are selected so that the pressure injection benchmark mainly reflects the relationship between the pressure increment and the actual injection volume when approaching the switching pressure, while reducing the impact of metering fluctuations in a single pressure window on the determination of subsequent injection volumes.

[0034] For the selected pressure window, the median of the injection volume parameter within the window is determined as the pressure injection baseline:

[0035] in, As a reference for pressure injection, The number of pressure windows selected. to This refers to the injection volume parameter corresponding to the selected pressure window. If a pressure window at the top of the ranking cannot be used to calculate the injection volume parameter due to missing data, subsequent effective pressure windows are selected from highest to lowest pressure to supplement the preset number. The resulting pressure injection baseline is used to determine the total injection volume based on the target pressure increment and is continuously updated after the subsequent pressure increase response is formed.

[0036] In one embodiment, when the test pressure reaches the switching pressure, the pressure testing system stops injecting liquid and maintains continuous pressure acquisition, allowing the test pressure to change naturally over time after the injection stops. A pressure sequence is formed from the continuously acquired test pressures and corresponding sampling times, reflecting the free pressure response at the switching pressure. The stable pressure is taken as the average of the continuous sampling values ​​at the end of the pressure sequence. The length of the continuous sampling segment is set according to the pressure acquisition frequency and the duration of the free pressure response, and the segment where the test pressure no longer exhibits a continuous unidirectional change is selected.

[0037] The pressure test system retrieves pressure peaks from the pressure sequence according to the sampling time order, identifying two consecutive pressure peaks located on the same side of the stable pressure. These two pressure peaks are selected either both above or both below the stable pressure. The difference in the occurrence time of the two pressure peaks is determined as the pressure oscillation period.

[0038] in, For pressure oscillation period, The moment when the first pressure peak occurs. This is the moment when the second pressure peak occurs. The pressure decay characteristic is determined by the following formula, based on the ratio of the deviations of the two pressure peaks relative to the stable pressure:

[0039] in, It is characterized by pressure attenuation. This is the first pressure peak. This is the second pressure peak. To stabilize the pressure, the pressure oscillation period is used to determine the time interval between injection actions corresponding to subsequent adjacent sub-injection volumes, and the pressure decay characteristic is used to determine the volume ratio relationship between each sub-injection volume. Together, they form a transient characteristic and are transmitted to the injection command group generation stage.

[0040] If there are missing samples in the pressure sequence, the pressure sequence will continue to be acquired until a continuous sampling segment is formed. If there are fewer than two effective pressure peaks, the acquisition time of the free pressure response will be extended, and a single pressure peak will not be used to determine the pressure oscillation period. If two consecutive pressure peaks located on the same side of the stable pressure cannot be determined after reaching the preset maximum acquisition time, a transient feature acquisition anomaly will be output, and the generation of injection command groups will be stopped. The preset maximum acquisition time is determined based on the observable duration of the free pressure response at the pressure switching point and the waiting time allowed by the pressure resistance test.

[0041] The pressure test system receives the target test pressure, current pressure, pressure injection reference, and transient characteristics, calculates the pressure margin between the target test pressure and the current pressure, and determines the target pressure increment that the current booster unit can withstand.

[0042] The current pressure boosting unit refers to a single pressure boosting process within the pressure boosting phase after a pressure switch, defined by the generation and execution of an injection command group and the acquisition of the subsequent pressure boosting response. When generating the injection command group, the current pressure is the stable pressure determined after the most recent cessation of injection.

[0043] The target pressure increment is converted into the total injection volume by combining the pressure injection benchmark. Then, the injection ratio of the total injection volume among the sub-injection volumes and the time interval between adjacent injection actions are determined by using transient characteristics, thus forming an injection command group.

[0044] For the pressure boosting unit that has completed the pressure boosting, the pressure test system reads the executed pressure boosting response, adjusts the injection volume of each sub-injection in the injection command group proportionally, and keeps the time interval unchanged. The adjusted injection command group enters the execution stage corresponding to the second pressure boosting speed.

[0045] In one embodiment, the pressure testing system reads the target test pressure and the current pressure before each current pressure boosting unit begins after a pressure switch, and determines the pressure margin based on the difference between the two. The pressure margin limits the pressure range that the current pressure boosting unit can continue to increase, and its calculation relationship is as follows:

[0046] in, For the first The pressure margin corresponding to the current boost unit. For the target test pressure, For the first The current pressure before the start of the current boost unit This is the sequence number of the current pressure boosting unit. The pressure test system determines the target pressure increment based on the pressure margin, ensuring that the target pressure increment decreases as the current pressure approaches the target test pressure. The expression for calculating the target pressure increment is:

[0047] in, For the target pressure increment, Assign parameters to the pressure margin. This represents the maximum allowable pressure increment for a single current boosting unit. The pressure margin allocation parameter is set based on the proximity of the current pressure to the target test pressure; the closer the current pressure is to the target test pressure, the smaller the value of the pressure margin allocation parameter. The maximum pressure increment is determined based on the pressure change range that a single current boosting unit can stably control at the second boosting rate.

[0048] After obtaining the target pressure increment, read the pressure injection reference and follow: Determine the total injection volume, of which, This is the total injection volume. The pressure injection reference is used. The pressure test system reads transient characteristics, divides the total injection volume into multiple sub-injection volumes, and sets time intervals for the injection actions corresponding to adjacent sub-injection volumes. Injection command groups are formed by each sub-injection volume, execution order, and time interval. These injection command groups are transmitted to the execution stage corresponding to the second pressurization rate. The executed pressurization response is used for processing in the next current pressurization unit.

[0049] In one embodiment, the transient characteristics consist of pressure decay characteristics and pressure oscillation period, and the pressure resistance test system uses the two to constrain the volume ratio between each sub-injection volume and the time interval between injection actions corresponding to adjacent sub-injection volumes, respectively.

[0050] For a given booster unit, the total injection volume can be divided into a first sub-injection volume and a second sub-injection volume, and the volume ratio relationship can be determined by the pressure decay characteristics using the following calculation expression:

[0051]

[0052]

[0053] in, The pressure decay characteristic used by the kth current boost unit is... For proportional parameters, This represents the volume ratio corresponding to the first injection volume. This represents the volume ratio corresponding to the second sub-injection volume, and the sum of the two volume ratios is 1. The first and second sub-injection volumes are respectively calculated according to: 、 It is confirmed that, among them, This is the first injection volume. This is the second injection volume. This represents the total injection volume.

[0054] The time interval between two adjacent injection actions is determined by the pressure oscillation period, according to the following formula:

[0055] in, For time intervals, The pressure oscillation cycle is defined as follows: The pressure test system organizes injection command groups according to the first sub-injection volume, the time interval, and the second sub-injection volume, ensuring that the injection action corresponding to the second sub-injection volume is located approximately half a pressure oscillation cycle from the free pressure response generated by the previous injection action. After the injection command group is formed, the volume ratio and time interval remain fixed within the same group. When entering the executed pressure boost response adjustment phase, only proportional changes in each sub-injection volume are allowed.

[0056] In one embodiment, the pressure testing system reads the most recently executed pressure boosting response before executing the injection command group, obtaining the actual pressure increment and actual injection volume from it. The first current pressure boosting unit after pressure switching uses the actual pressure increment and actual injection volume corresponding to the pressure window with the highest pressure upper limit and valid data within the preset pressure range. Subsequent current pressure boosting units use the actual pressure increment and actual injection volume formed by the previous current pressure boosting unit.

[0057] The pressure increase relationship between the actual pressure increment and the actual injection volume is determined by the following formula: in, For boosting relationship, This represents the actual increase in pressure. The actual injection volume. The expected pressure increment is determined by combining the pressure increase relationship and the total injection volume of the current injection command group, calculated using the following formula:

[0058] in, To anticipate the increase in pressure, This represents the total injection volume. The injection adjustment parameters are then determined based on the target pressure increment and the expected pressure increment, calculated using the following formula:

[0059] in, Adjusting parameters for injection For the target pressure increment, The expected pressure increment is set to 1. When the expected pressure increment does not exceed the target pressure increment, the injection adjustment parameter is set to 1; when the expected pressure increment exceeds the target pressure increment, the injection adjustment parameter is set to less than 1.

[0060] The pressure testing system applies the same injection adjustment parameter to each sub-injection volume, ensuring that each sub-injection volume changes proportionally, maintaining the same volume ratio, and keeping the time interval between injection actions corresponding to adjacent sub-injection volumes constant. The adjusted sub-injection volumes and time intervals are written into the injection command group and transmitted to the execution stage corresponding to the second pressurization rate. If the actual injection volume is missing or not greater than zero, the most recent valid pressurization response with the actual injection volume is used instead.

[0061] During the pressure boosting phase after pressure switching, the pressure testing system executes injection command sets at a second boosting rate lower than the first boosting rate. Injection stops after each injection command set is completed, and the boosting response is recorded. Both the first and second boosting rates represent the target rate of change of test pressure over time during injection. During the execution of injection command sets, the controller determines the actual boosting rate based on the current pressure continuously acquired by the pressure sensor and adjusts the output of the boosting pump and the opening state of the injection control valve to ensure the actual boosting rate follows the second boosting rate. When the actual injection volume corresponding to a sub-injection volume reaches that sub-injection volume, the current injection action stops, and the next injection action is executed after a time interval. The stable pressure increment, actual injection volume, and free pressure response are obtained from the boosting response. The pressure injection reference and transient characteristics are updated, and the next injection command set is generated using the updated pressure injection reference and transient characteristics.

[0062] Perform the test group by group in the same manner until the current pressure enters the allowable pressure range. Once the current pressure enters the allowable pressure range, stop increasing the pressure and begin the pressure resistance timer. After the pressure resistance timer completes, reduce the pressure to zero to end the pressure resistance test of the fiberglass pipe.

[0063] In one embodiment, the pressure testing system stops injecting after completing all injection actions of an injection command group, records the stable pressure before and after the execution of the injection command group, and accumulates the actual injection volume of the injection command group. The stable pressure is determined within the range where the test pressure no longer changes unidirectionally after the injection stops. The stable pressure before execution is used as the starting point of this pressure increase response, and the stable pressure after execution is used as the ending point. The difference between the two is determined as the stable pressure increment. If the stable pressure increment is not greater than zero or the actual injection volume record is incomplete, this pressure increase response does not participate in the pressure injection benchmark update, and the most recent valid pressure injection benchmark continues to be used.

[0064] When the stable pressure increment and actual injection volume are effective, update the pressure injection baseline according to the following formula:

[0065] in, For the updated pressure injection benchmark, The pressure injection baseline before the update, This is the actual volume of fluid injected. To stabilize the pressure increment, To update parameters, update parameters. Take a value between 0 and 1. The update parameter is used to limit the update range of the pressure injection baseline in this pressurization response. It can be determined based on the degree of fluctuation of the ratio of actual injection volume to stable pressure increment in multiple consecutive pressurization responses; the update parameter is increased when the degree of fluctuation increases and decreased when the degree of fluctuation decreases.

[0066] After completing the stable pressure recording, the free pressure response formed when the injection stops is acquired. The pressure oscillation period and pressure decay characteristics are re-determined from the pressure sequence corresponding to the free pressure response, and the transient characteristics are updated with the re-determined pressure oscillation period and pressure decay characteristics. The updated pressure injection baseline is used to determine the total injection volume of the next injection command group, and the updated transient characteristics are used to determine the volume ratio between each sub-injection volume and the time interval between adjacent injection actions.

[0067] The next injection command group is generated when the current pressure has not entered the allowable pressure range; the generation of the next injection command group is stopped and the pressure resistance timer is entered when the current pressure enters the allowable pressure range.

[0068] In one embodiment, a fiberglass pipe with a length of 6m, an inner diameter of 200mm, and a wall thickness of 12mm is selected for a pressure resistance test. Based on the corresponding pressure resistance test requirements for the fiberglass pipe, the target test pressure is determined to be 2.40MPa, and the switching pressure is determined to be 75% of the target test pressure, i.e., 1.80MPa. The allowable pressure deviation is ±0.02MPa, thus forming an allowable pressure range of 2.38MPa to 2.42MPa.

[0069] The first pressurization rate was set to 0.08 MPa / s, and the second pressurization rate was set to 0.02 MPa / s. The pressure acquisition frequency was set to 100 Hz, and the actual injection volume was recorded with a metering resolution of 0.1 mL. After confirming the injection, venting, and sealing status of the FRP tube, the pressure resistance test system controlled the current pressure to continuously increase at the first pressurization rate, and simultaneously acquired the current pressure and the actual injection volume.

[0070] After the current pressure enters the preset pressure range of 1.32MPa to 1.80MPa, the preset pressure range is continuously divided into 6 pressure windows. The pressure ranges of each pressure window are 1.32MPa to 1.40MPa, 1.40MPa to 1.48MPa, 1.48MPa to 1.56MPa, 1.56MPa to 1.64MPa, 1.64MPa to 1.72MPa, and 1.72MPa to 1.80MPa, respectively. The pressure increment corresponding to each pressure window is 0.08MPa.

[0071] The actual injection volumes obtained from the six pressure windows were 18.0 mL, 18.6 mL, 19.2 mL, 19.7 mL, 20.3 mL, and 20.8 mL, respectively. The injection volume parameters for each pressure window were determined by dividing the actual injection volume by the pressure increment. For example, the first pressure window corresponds to 18.0 mL ÷ 0.08 MPa = 225.00 mL / MPa. After calculation in the same way, the injection volume parameters for the six pressure windows were 225.00 mL / MPa, 232.50 mL / MPa, 240.00 mL / MPa, 246.25 mL / MPa, 253.75 mL / MPa, and 260.00 mL / MPa, respectively.

[0072] like Figure 2 As shown, the horizontal axis represents six pressure windows arranged in ascending order of pressure, and the vertical axis represents the injection volume parameter for each window. The blue bars correspond to the first three pressure windows that were not selected, and the orange bars correspond to the fourth to sixth pressure windows selected from highest to lowest pressure. The injection volume parameters for the three selected pressure windows are 246.25 mL / MPa, 253.75 mL / MPa, and 260.00 mL / MPa, respectively. The median of the three injection volume parameters, 253.75 mL / MPa, is taken as the pressure injection baseline. Figure 2 The red dashed line in the figure represents the formed pressure injection reference, and the pressure injection reference enters the injection command group generation process after the pressure is switched.

[0073] When the current pressure reaches 1.80 MPa, the injection is stopped, and a pressure sequence is continuously acquired for 10 seconds at a pressure acquisition frequency of 100 Hz. The average pressure within the last 2 seconds of the pressure sequence is taken as the stable pressure, which is 1.792 MPa in this case.

[0074] like Figure 3As shown, the horizontal axis represents the time after injection stops, and the vertical axis represents the test pressure. The free pressure response forms a pressure peak of 1.806 MPa at 1.2 s and a pressure peak of 1.799 MPa at 3.6 s. Both pressure peaks are located on the same side of the stable pressure of 1.792 MPa. The two pressure peaks occur 2.40 s apart, therefore the pressure oscillation period is determined to be 2.40 s.

[0075] The deviation between pressure peak 1 and stable pressure is 0.014 MPa, and the deviation between pressure peak 2 and stable pressure is 0.007 MPa. Dividing 0.007 MPa by 0.014 MPa yields a pressure decay characteristic of 0.50. Figure 3 The two red dots in the diagram correspond to two pressure peaks, the green dashed line corresponds to the stable pressure, and the pressure oscillation period of 2.40s and the pressure decay characteristic of 0.50 together constitute the current transient characteristics.

[0076] With a stable pressure of 1.792 MPa as the current pressure, the difference between the target test pressure and the current pressure is 0.608 MPa. Therefore, the pressure margin of the current booster unit is 0.608 MPa. The pressure margin allocation parameter is set to 0.30, and the maximum allowable pressure increment for a single current booster unit is set to 0.18 MPa. Multiplying 0.608 MPa by 0.30 yields 0.1824 MPa. Since 0.1824 MPa exceeds the maximum pressure increment, the target pressure increment for the current booster unit is set to 0.18 MPa.

[0077] Multiplying the baseline injection pressure of 253.75 mL / MPa by the target pressure increment of 0.18 MPa yields a total injection volume of 45.675 mL for the current pressurization unit. Taking the square root of the pressure decay characteristic of 0.50, a proportionality parameter of 0.707 is obtained. Based on this parameter, the volume ratio between the two sub-injection volumes is determined to be 0.586:0.414. After allocation according to the total injection volume, the first sub-injection volume is 26.8 mL, and the second sub-injection volume is 18.9 mL.

[0078] When the pressure oscillation period is 2.40s, the time interval between the injection actions corresponding to two adjacent sub-injection volumes is taken as half of the pressure oscillation period, i.e., 1.20s.

[0079] like Figure 4 As shown, the horizontal axis represents the execution time of the injection command group, and the vertical axis represents the sub-injection volume. The blue bar at 0s represents the first sub-injection volume of 26.8mL, and the orange bar at 1.20s represents the second sub-injection volume of 18.9mL. The two injection actions are separated by a time interval of 1.20s. Figure 4The right side is marked with a pressure oscillation period of 2.40s and an injection ratio of 0.586:0.414, thus forming the current injection command group. When executing the current injection command group, the pressure test system limits the actual pressurization process to the pressurization state corresponding to the second pressurization rate.

[0080] After the first injection command group was executed, the injection was stopped, and the stable pressure, actual injection volume, and free pressure response before and after execution were obtained. The stable pressure before execution was 1.792 MPa, and the stable pressure after execution was 1.965 MPa, with a stable pressure increment of 0.173 MPa. The actual injection volume was 45.6 mL. Dividing 45.6 mL by 0.173 MPa yields 263.58 mL / MPa.

[0081] The update parameter is set to 0.70. The update uses 70% of the original pressure injection baseline and 30% of the current actual injection volume to the stable pressure increment ratio, resulting in a new pressure injection baseline of 256.70 mL / MPa. After the first injection command group is executed, the free pressure response corresponds to a pressure oscillation period of 2.25 s and a pressure decay characteristic of 0.46. The new pressure oscillation period and pressure decay characteristic replace the transient characteristics used in the previous pressurization unit and, together with the new pressure injection baseline, enter the next injection command group generation process.

[0082] The subsequent injection command groups were executed in the same manner. After the second injection command group was completed, the actual injection volume was 33.4 mL, and the stable pressure increased from 1.965 MPa to 2.090 MPa. The actual injection volume of the third injection command group was 23.0 mL, and the stable pressure increased from 2.090 MPa to 2.184 MPa. After the second and third injection command groups were completed, the pressure injection benchmarks were updated to 259.85 mL / MPa and 255.30 mL / MPa, respectively.

[0083] The actual pressure increment generated by the third injection command group is 0.094 MPa, and the actual injection volume is 23.0 mL. Therefore, the pressure increase relationship between the actual pressure increment and the actual injection volume is 0.094 MPa ÷ 23.0 mL, which is approximately 0.00409 MPa / mL.

[0084] When the fourth injection command group is generated, the current pressure is 2.184 MPa, and the pressure margin is 0.216 MPa. The pressure margin allocation parameter is set to 0.25, therefore the target pressure increment is determined to be 0.054 MPa. Using the current pressure injection baseline of 255.30 mL / MPa, the unadjusted total injection volume is 13.79 mL. The pressure oscillation period corresponding to the free pressure response after the third injection command group is completed is 1.95 s; therefore, the time interval between injection actions corresponding to adjacent sub-injection volumes in the fourth injection command group is determined to be 0.975 s.

[0085] Using a pressure increase of 0.00409 MPa / mL to predict the pressure increment of 13.79 mL, the expected pressure increment is approximately 0.0564 MPa. Since the expected pressure increment is higher than the target pressure increment by 0.054 MPa, the injection adjustment parameter of 0.958 is obtained by dividing 0.054 by 0.0564. Each sub-injection volume in the fourth injection command group is multiplied by 0.958, adjusting the total injection volume from 13.79 mL to approximately 13.20 mL, while maintaining the original volume ratio between the sub-injection volumes and the time interval of 0.975 s.

[0086] The actual injection volumes after the execution of the fourth to ninth injection command groups were 13.2 mL, 10.5 mL, 8.2 mL, 6.5 mL, 5.3 mL, and 4.2 mL, respectively, corresponding to stable pressures of 2.235 MPa, 2.274 MPa, 2.306 MPa, 2.335 MPa, 2.362 MPa, and 2.383 MPa. After each pressure boost response participated in the pressure injection baseline update, the pressure injection baseline was successively set at 256.36 mL / MPa, 260.22 mL / MPa, 259.03 mL / MPa, 248.56 mL / MPa, 232.88 mL / MPa, and 223.02 mL / MPa.

[0087] like Figure 5 As shown, the first row of the horizontal axis represents the initial state and nine injection command groups from G1 to G9. The second row of the horizontal axis represents the corresponding pressure injection references. The vertical axis represents the stable pressure formed after each injection command group is executed. The stable pressure changes sequentially from the initial 1.792 MPa to 1.965 MPa, 2.090 MPa, 2.184 MPa, 2.235 MPa, 2.274 MPa, 2.306 MPa, 2.335 MPa, 2.362 MPa, and 2.383 MPa.

[0088] Figure 5 The injection adjustment parameter of 0.958 and the unchanged time interval of 0.975s are marked at position G4 to indicate that the pressurization response has been executed to adjust the injection volume of the injection command group proportionally without changing the time interval determined by the transient characteristics. Figure 5 The two blue pressure boundaries at the top correspond to the allowable pressure range of 2.38MPa to 2.42MPa. After G9 is executed, the stable pressure is 2.383MPa, which has entered the allowable pressure range. Therefore, no further injection command group will be generated.

[0089] After entering the permissible pressure range, the pressure resistance timer was started. This pressure resistance timer was set to 600 seconds according to the corresponding pressure resistance test requirements for the fiberglass pipe. During the pressure resistance timer, the test pressures recorded at 0s, 120s, 240s, 360s, 480s, and 600s were 2.383MPa, 2.3825MPa, 2.3840MPa, 2.3815MPa, 2.3835MPa, and 2.3820MPa, respectively, all within the permissible pressure range of 2.38MPa to 2.42MPa.

[0090] like Figure 6 As shown, the horizontal axis represents the pressure withstand time and the time to reduce pressure to zero, and the vertical axis represents the test pressure. The two blue horizontal boundaries in the figure correspond to the allowable pressure range. The pressure withstand time interval is from 0s to 600s, during which the test pressure remains within the allowable pressure range. At 600s, the pressure withstand time is completed and the pressure begins to decrease to zero. The test pressure decreases to 1.80MPa, 1.20MPa, and 0.60MPa at 620s, 640s, and 660s respectively, and reaches 0MPa at 680s, completing the pressure withstand test.

[0091] This pressure withstand test ultimately produced a complete test record with a target test pressure of 2.40 MPa, a switching pressure of 1.80 MPa, an allowable pressure range of 2.38 MPa to 2.42 MPa, an initial pressure injection reference of 253.75 mL / MPa, a pressure oscillation period of 2.40 s at the switching pressure, a pressure decay characteristic of 0.50, a G9 stable pressure of 2.383 MPa, and a pressure withstand time of 600 s. In the first pressurization rate stage, the pressure injection reference was established using the pressure increment and the actual injection volume, and the transient characteristics were formed using the free pressure response after injection stopped. In the second pressurization rate stage, injection command sets were continuously generated using the pressure margin, the pressure injection reference, and the transient characteristics. The subsequent injection command sets were updated using the executed pressurization response, gradually bringing the stable pressure into the allowable pressure range, before completing the pressure withstand time and depressurizing to zero, thus forming a continuous closed-loop dual-speed pressurization pressure withstand test process.

[0092] like Figure 7 As shown, a pressure resistance testing device for fiberglass pipes based on dual-speed pressure boosting includes the following modules.

[0093] The pressure boosting and foundation building module consists of a pressure sensor, a liquid injection metering unit, a booster pump, a liquid injection control valve, and a controller. The pressure sensor continuously acquires the current pressure, the liquid injection metering unit records the actual liquid injection volume during the pressure boosting process, and the controller receives the target test pressure, switching pressure, and allowable pressure range, and controls the booster pump to operate at the first pressure boosting rate. When the switching pressure is reached, the controller closes the liquid injection control valve, determines the pressure injection baseline based on the acquired pressure increment and the actual liquid injection volume, and generates a free pressure response and transient characteristics based on the pressure acquisition results after the liquid injection stops.

[0094] The instruction orchestration module consists of a processor, a memory, and a timing control unit. The memory stores the target test pressure, current pressure, pressure injection reference, transient characteristics, and executed pressure boosting responses. The processor determines the injection ratio of each sub-injection volume and the time interval between adjacent injection actions based on the pressure margin between the target test pressure and the current pressure, the pressure injection reference, and the transient characteristics, forming an injection instruction group. The timing control unit stores the execution timing of the injection instruction group and maintains the time interval unchanged when the processor adjusts each sub-injection volume based on the executed pressure boosting responses.

[0095] The pressure-resistant execution module consists of a booster pump, an injection control valve, a pressure relief valve, a pressure sensor, an injection volume metering unit, a timer, and a controller. The controller drives the booster pump and injection control valve to execute injection command sets according to the second pressurization rate. The pressure sensor and injection volume metering unit synchronously acquire the pressurization response corresponding to each injection command set. The controller uses the pressurization response to update the pressure injection benchmark and transient characteristics and generate the next injection command set. When the current pressure enters the allowable pressure range, the controller stops further pressurization and starts the timer to perform pressure-resistant timing. After the pressure-resistant timing is completed, the controller stops the booster pump, closes the injection control valve, and opens the pressure relief valve to reduce the current pressure to zero.

[0096] It should also be noted that the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0097] The various embodiments in this invention are described in a progressive manner. Similar or identical parts between embodiments can be referred to mutually. Each embodiment focuses on describing the differences from other embodiments. In particular, the device embodiments are basically similar to the method embodiments, so the description is relatively simple; relevant parts can be referred to the descriptions of the method embodiments.

Claims

1. A pressure resistance test method for fiberglass pipes based on dual-speed pressure increase cascading, characterized in that, The method includes: Obtain the target test pressure, switching pressure, and allowable pressure range; increase the pressure to the switching pressure at a first pressurization rate; determine the pressure injection reference based on the pressure increment and the actual injection volume; stop injection; and determine the transient characteristics based on the free pressure response. The injection command group containing the injection ratio and time interval is generated from the difference between the target test pressure and the current pressure, the pressure injection reference and the transient characteristics. The injection volume of the injection command group is adjusted proportionally according to the executed pressure boost response and the time interval is maintained. The injection command group is executed at a second pressure increase rate lower than the first pressure increase rate. The pressure injection reference and the transient characteristics are updated by the pressure increase response, and the next injection command group is generated until the current pressure reaches the allowable pressure range. After the current pressure reaches the allowable pressure range, the pressure is tested and the pressure is reduced to zero.

2. The method according to claim 1, characterized in that, The switching pressure is determined according to a preset ratio of the target test pressure, and the allowable pressure range is determined by the target test pressure and the allowable pressure deviation.

3. The method according to claim 1, characterized in that, The determination of the pressure injection benchmark by pressure increment and actual injection volume includes: During the process of increasing the pressure to the switching pressure at the first pressurization rate, multiple pressure windows are determined within a preset pressure range before the switching pressure. The pressure increment and actual injection volume in each pressure window are obtained, and the pressure injection benchmark is determined based on the pressure increment and actual injection volume in each pressure window.

4. The method according to claim 3, characterized in that, The determination of the pressure injection benchmark based on the pressure increment and actual injection volume within each pressure window includes: The injection volume parameter for each pressure window is determined based on the ratio between the actual injection volume and the pressure increment within each pressure window. A preset number of pressure windows are selected from high to low according to the upper pressure limit of each pressure window, and the pressure injection benchmark is determined according to the injection volume parameter of the selected pressure window.

5. The method according to claim 1, characterized in that, The cessation of fluid injection, determined by the transient characteristics of the free pressure response, includes: Obtain the pressure sequence after stopping the injection; Determine the steady pressure and two consecutive pressure peaks located on the same side of the steady pressure from the pressure sequence; The pressure oscillation period is determined based on the occurrence times of the two pressure peaks, the pressure decay characteristic is determined based on the deviation of the two pressure peaks from the stable pressure, and the pressure oscillation period and the pressure decay characteristic are used as the transient characteristics.

6. The method according to claim 1, characterized in that, The generation of the injection command group from the difference between the target test pressure and the current pressure, the pressure injection reference, and the transient characteristics includes: The difference between the target test pressure and the current pressure is determined as the pressure margin; The target pressure increment of the current booster unit is determined based on the pressure margin, and the total injection volume is determined based on the target pressure increment and the pressure injection reference. Based on the transient characteristics, the total injection volume is divided into multiple sub-injection volumes, and the time interval between injection actions corresponding to adjacent sub-injection volumes is determined to obtain the injection command group.

7. The method according to claim 6, characterized in that, The transient characteristics include pressure decay characteristics and pressure oscillation period; The step of allocating the total injection volume into multiple sub-injection volumes based on the transient characteristics, and determining the time interval between injection actions corresponding to adjacent sub-injection volumes, includes: The volume ratio between each of the sub-injection volumes is determined based on the pressure decay characteristics, the time interval between injection actions corresponding to adjacent sub-injection volumes is determined based on the pressure oscillation period, and the injection command group is generated based on the volume ratio and the time interval.

8. The method according to claim 6, characterized in that, The step of adjusting the injection volume of the injection command group proportionally according to the executed pressurization response includes: The pressure increase relationship between the actual pressure increase and the actual injection volume is determined based on the actual pressure increase and the actual injection volume in the executed pressure increase response. The expected pressure increase is determined based on the pressure increase relationship and the total injection volume. The injection adjustment parameters for proportionally adjusting each of the sub-injection volumes are determined based on the target pressure increase and the expected pressure increase. Each of the sub-injection volumes is adjusted proportionally according to the injection adjustment parameters, while keeping the time interval unchanged.

9. The method according to claim 1, characterized in that, The step of updating the pressure injection reference and the transient characteristics based on the pressure boost response and generating the next injection command set includes: After the injection command group is executed, the stable pressure, actual injection volume and free pressure response before and after the execution of the injection command group are obtained, and the stable pressure increment is determined based on the stable pressure before and after execution. The pressure injection benchmark is updated based on the stable pressure increment and the actual injection volume, the transient characteristics are updated based on the free pressure response, and the next injection command group is generated based on the updated pressure injection benchmark and the updated transient characteristics.

10. A pressure testing device for fiberglass pipes based on a dual-speed pressure-increasing arrangement, used to implement the pressure testing method for fiberglass pipes based on a dual-speed pressure-increasing arrangement as described in any one of claims 1 to 9, characterized in that, The device includes: The pressure boosting and base-building module is used to obtain the target test pressure, switching pressure and allowable pressure range, increase the pressure to the switching pressure at a first pressure boosting rate, determine the pressure injection reference by the pressure increment and the actual injection volume, stop the injection, and determine the transient characteristics by the free pressure response. The instruction orchestration module is used to generate an injection instruction group containing the injection ratio and time interval from the difference between the target test pressure and the current pressure, the pressure injection reference and the transient characteristics, and to adjust the injection volume of the injection instruction group proportionally according to the executed pressure boost response while maintaining the time interval; The pressure-resistant execution module is used to execute the injection command group at a second pressure-increasing rate lower than the first pressure-increasing rate, update the pressure injection reference and the transient characteristics by the pressure-increasing response and generate the next injection command group until the current pressure reaches the allowable pressure range. After the current pressure reaches the allowable pressure range, the pressure-resistant timing is reduced to zero.

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