A monitoring method and monitoring system for a plunger pump

Abstract

The application provides a monitoring method and a monitoring system of a plunger pump, relates to a driving system element state monitoring technology, and comprises the following steps: collecting a pump body vibration frequency, an outlet flow, an outlet pressure and an internal pressure of the pump body of the plunger pump in real time; calculating an oil film thickness of a friction pair in the plunger pump according to the pump body vibration frequency, the outlet flow, the outlet pressure and the internal pressure of the pump body; and judging a working condition of the plunger pump based on the oil film thickness of the friction pair in the plunger pump. The application provides the monitoring method and the monitoring system of the plunger pump, can identify a dangerous working condition, and can reduce the probability of a tunnel boring equipment stoppage due to a fault.

Description

Technical Field

[0001] This invention relates to drive system component condition monitoring technology, and particularly to a monitoring method and system for a plunger pump. Background Technology

[0002] The main drive unit of a tunnel boring machine (TBM) typically uses a high-displacement (≥500ml / r) axial piston pump. A malfunction in this pump can lead to work stoppages, extended construction periods, and significant economic losses. Therefore, monitoring of the main drive pump is necessary to reduce the probability of malfunctions and work stoppages.

[0003] Currently, the main drive pump monitoring system for tunnel boring machines (TBMs) often only analyzes the numerical values ​​of signals. By the time an anomaly is detected, the fault has often already occurred, and early warning is not possible. Although in recent years, with increased research focus on intelligent monitoring in the construction machinery field, many studies have incorporated fault diagnosis modules into monitoring systems to diagnose components exhibiting fault signals. However, this method cannot assess the health status of components in real time, nor can it evaluate the lifespan of components.

[0004] In view of this, based on years of experience in production and design in this and related fields, the inventor has designed a monitoring method and system for plunger pumps through repeated experiments, in order to solve the problems existing in the prior art. Summary of the Invention

[0005] This invention proposes a monitoring method and system for plunger pumps, which can identify dangerous working conditions and thus reduce the probability of tunnel excavation equipment downtime due to malfunctions.

[0006] To achieve the above objectives, the present invention proposes a monitoring method for a plunger pump, wherein the monitoring method includes:

[0007] The pump body vibration frequency, outlet flow rate, outlet pressure, and internal pressure of the plunger pump are collected in real time.

[0008] The oil film thickness of the internal friction pair of the plunger pump is calculated based on the pump body vibration frequency, outlet flow rate, outlet pressure, and pump body internal pressure.

[0009] The operating condition of the plunger pump is determined based on the oil film thickness of the internal friction pair.

[0010] The present invention also proposes a monitoring system for a plunger pump, wherein the monitoring system includes:

[0011] The data acquisition module collects pump body vibration frequency information, outlet flow rate information, outlet pressure information, and pump body internal pressure information;

[0012] The operating condition identification module is electrically connected to the data acquisition module. The operating condition identification module calculates the oil film thickness of the internal friction pair of the plunger pump based on the pump body vibration frequency information, the outlet flow rate information, the outlet pressure information, and the pump body internal pressure information. Then, based on the oil film thickness of the internal friction pair of the plunger pump, it determines the operating condition of the plunger pump.

[0013] Compared with the prior art, the monitoring method and system for plunger pumps proposed in this invention have the following characteristics and advantages:

[0014] The monitoring method and system for plunger pumps proposed in this invention calculate and process the pump body vibration frequency, outlet flow rate, outlet pressure and internal pressure of the pump body collected in real time to determine the operating condition of the plunger pump, thereby enabling timely identification of dangerous operating conditions and reducing the probability of plunger pump equipment shutdown due to failure.

[0015] The monitoring method and system for plunger pumps proposed in this invention can be used for plunger pumps in the main drive unit of tunnel boring machines (TBMs) to identify dangerous operating conditions of the TBM main drive unit in a timely manner, thereby reducing the probability of tunnel boring equipment downtime due to malfunction. Attached Figure Description

[0016] The accompanying drawings described herein are for illustrative purposes only and are not intended to limit the scope of the invention in any way. Furthermore, the shapes and proportions of the components in the drawings are merely illustrative to aid in understanding the invention and do not specifically limit the shapes and proportions of the components. Those skilled in the art, guided by the teachings of this invention, can select various possible shapes and proportions to implement the invention according to specific circumstances.

[0017] Figure 1 This is a flowchart of the monitoring method for the plunger pump proposed in this invention;

[0018] Figure 2 This is a schematic diagram of the monitoring system for the plunger pump proposed in this invention;

[0019] Figure 3 This is a schematic diagram illustrating a specific implementation process of an embodiment of the present invention.

[0020] Explanation of reference numerals in the attached figures:

[0021] 100. Monitoring system for plunger pumps; 10. Accelerometer sensor;

[0022] 20. Pump outlet flow meter; 30. Pump outlet pressure sensor;

[0023] 40. Pump drain port pressure sensor; 50. Data transmission module;

[0024] 200. Piston pump; 210. Oil tank;

[0025] 220. Oil replenishment pump. Detailed Implementation

[0026] The details of the present invention can be more clearly understood by referring to the accompanying drawings and the description of specific embodiments. However, the specific embodiments of the present invention described herein are for illustrative purposes only and should not be construed as limiting the invention in any way. Under the teachings of this invention, those skilled in the art can conceive of any possible modifications based on the invention, and these should all be considered to fall within the scope of the invention.

[0027] It should be noted that when a component is referred to as "fixed to" or "set on" another component, it can be directly on the other component or there may be an intervening component. When a component is referred to as "connected to" another component, it can be directly connected to the other component or there may be an intervening component.

[0028] This invention proposes a monitoring method for plunger pumps, such as... Figure 1 As shown, the monitoring method includes:

[0029] The pump body vibration frequency, outlet flow rate, outlet pressure, and internal pressure of the plunger pump are collected in real time.

[0030] Calculate the oil film thickness of the internal friction pair of the plunger pump based on the pump body vibration frequency, outlet flow rate, outlet pressure, and internal pressure of the pump body.

[0031] The operating condition of the piston pump is determined based on the oil film thickness of the internal friction pair.

[0032] The present invention also proposes a monitoring system 100 for a plunger pump. The monitoring system includes a data acquisition module and a working condition identification module. The data acquisition module acquires pump body vibration frequency information, outlet flow rate information, outlet pressure information, and pump body internal pressure information of the plunger pump 200. The working condition identification module is electrically connected to the data acquisition module. Based on the pump body vibration frequency information, outlet flow rate information, outlet pressure information, and pump body internal pressure information, the working condition identification module calculates the oil film thickness of the friction pair inside the plunger pump, and then determines the working condition of the plunger pump based on the oil film thickness of the friction pair inside the plunger pump.

[0033] The monitoring method and system for plunger pumps proposed in this invention calculate and process the pump body vibration frequency, outlet flow rate, outlet pressure and internal pressure of the pump body collected in real time to determine the operating condition of the plunger pump, thereby enabling timely identification of dangerous operating conditions and reducing the probability of plunger pump equipment shutdown due to failure.

[0034] The plunger pump monitoring method and system proposed in this invention can be used for the plunger pump of the main drive unit of tunnel boring machine (TBM) to identify dangerous operating conditions of the TBM main drive unit in a timely manner, thereby reducing the probability of TBM downtime due to malfunction. In an optional embodiment of this invention, the data acquisition module includes an acceleration sensor 10, a pump outlet flow meter 20, a pump outlet pressure sensor 30, and a pump drain port pressure sensor 40. The acceleration sensor 10 is arranged on the pump casing and rear end cover of the plunger pump to collect the pump body vibration frequency information; the pump outlet flow meter 20 is arranged at the plunger pump outlet to collect the plunger pump outlet flow information; the pump outlet pressure sensor 30 is arranged at the plunger pump outlet to collect the plunger pump outlet pressure information; and the pump drain port pressure sensor 40 is arranged at the plunger pump drain port to collect the internal pressure information of the plunger pump body.

[0035] In an optional embodiment of the present invention, the monitoring system 100 further includes a life prediction module, which predicts the service life of the plunger pump based on pump body vibration frequency information and outlet flow information.

[0036] In one optional example of this implementation, the operating condition identification module is located in the cloud, and the life prediction module is located on a PC.

[0037] In an optional example, the monitoring system 100 also includes a host computer display module set on a PC to display the industrial control judgment results.

[0038] In an optional embodiment of the present invention, the monitoring system 100 further includes a data transmission module 50, which is used to receive information collected by the data acquisition module and transmit the data to the working condition identification module.

[0039] In an optional embodiment of the invention, the plunger pump 200 further includes an oil tank 210 and a replenishing pump 220.

[0040] In an optional embodiment of the present invention, when the oil film thickness of the friction pair is less than a threshold, the plunger pump is determined to be in a dangerous operating condition.

[0041] In one optional example of this implementation, the threshold is selected in the range of 0-20 micrometers.

[0042] In an optional embodiment of the present invention, a friction pair oil film thickness database is established. The database includes multiple reference oil film thicknesses, each of which corresponds to a different operating condition. The reference oil film thickness is called up and compared with the calculated oil film thickness of the friction pair to monitor the operating condition of the plunger pump.

[0043] In an optional embodiment of the present invention, the calculation step of the oil film thickness of the friction pair includes:

[0044] Initialize the oil film thickness and oil film thickness change rate of the friction pair;

[0045] Using the outlet flow rate, outlet pressure, and internal pressure of the pump body as calculation boundary conditions, the surface force of the friction pair oil film is solved.

[0046] The initial oil film thickness is used as the initial value of the oil film thickness. The oil film of the friction pair is divided into m×n grid points. The Reynolds equation is calculated through a cyclic structure to obtain the initial value of the oil film pressure at each grid point.

[0047] By using the oil film pressure and surface force and overturning moment balance equations of the friction pair, the oil film thickness at each grid point of the friction pair is obtained, and the minimum value of the above oil film thickness is output as the oil film thickness of the friction pair.

[0048] In an optional example of this implementation, the oil film thickness of the internal friction pair of the plunger pump includes the oil film thickness of the plunger pair, the oil film thickness of the slipper pair, and the oil film thickness of the distribution pair.

[0049] In an optional embodiment of the invention, the monitoring method further includes predicting the service life of the plunger pump based on the vibration frequency and outlet flow rate.

[0050] In one optional example of this implementation, a plunger pump life prediction neural network is established. The plunger pump's rotational speed, vibration frequency (vibration signal), outlet pressure, and outlet flow rate are input into the neural network. The neural network estimates the remaining predicted life of the plunger pump based on the vibration frequency and outlet flow rate.

[0051] In an optional example, the establishment of the plunger pump life prediction neural network includes:

[0052] Accelerated degradation tests were conducted on plungers using a constant stress load spectrum, and a plunger pump database was established.

[0053] The characteristic parameters of vibration frequency are extracted from the plunger pump database, and the characteristic parameters and the volumetric efficiency of the plunger pump are used as the training set.

[0054] The lifespan prediction neural network is established by training the neural network on the training set.

[0055] The following detailed description, with reference to an embodiment, illustrates the specific implementation process of the monitoring method and system for the plunger pump proposed in this invention:

[0056] Please refer to Figure 2 , Figure 3The plunger pump monitoring system 100 includes a data acquisition module, a data transmission module, a working condition identification module, and a life prediction module. Due to the high computing power requirements of the working condition identification module, it is located in the cloud; the input signal is processed and transmitted to the cloud for identification and calculation. The life prediction module and the host computer display module are located on a PC for easy operation by construction personnel. The data transmission module belongs to the data transmission layer.

[0057] The data acquisition module includes an acceleration sensor for monitoring the plunger pump housing, a pressure sensor and flow meter (flow sensor) at the high-pressure side outlet of the plunger pump, a pressure sensor at the plunger pump's oil replenishment port, and a pressure sensor at the pump's oil drain port to collect vibration frequency signals and flow signals during the operation of the plunger pump. The collected signals are amplified by the signal conditioning circuit and then transmitted to the PC terminal for display and life prediction via the data transmission module. They are also transmitted to the cloud via a wireless transmission network for calculation by the hazardous condition identification module. After the calculation is completed, the results are returned to the PC terminal for display.

[0058] Specifically, an accelerometer is installed on the pump casing and the rear end cover of the pump to collect vibration sensing signals of the pump body during the tunnel boring machine's excavation; a pump outlet flow meter is placed at the pump outlet to collect pump outlet flow signals during the tunnel boring machine's excavation; a pump outlet pressure sensor is used to collect pump outlet pressure signals during the tunnel boring machine's excavation; and a pump drain port pressure sensor is used to collect internal pressure signals of the pump body during the tunnel boring machine's excavation.

[0059] In this embodiment, the method for identifying hazardous operating conditions of a plunger pump includes:

[0060] The signals are collected in real time by the pump outlet pressure sensor and pump outlet flow meter (sensor), the pump replenishment port pressure sensor and the pump drain port pressure sensor at the high pressure side outlet of the plunger pump.

[0061] The data transmission module includes a digital amplifier board and a data acquisition card. The digital amplifier board amplifies the signal strength to a level that the acquisition card can detect (0-10V). The data is then transmitted to the cloud-based working condition identification module (hazardous working condition identification module) via the data acquisition card.

[0062] In the operating condition identification module, the first step is to calculate the variation law of the plunger pair oil film thickness under the current operating condition. The calculation process is as follows: a. Initialize the plunger pair oil film thickness and oil film thickness change rate; b. Using real-time signals such as pressure and flow rate as boundary conditions, solve the oil film surface force using the plunger pair dynamic equation; c. Using real-time signals such as pressure and flow rate as calculation boundary conditions, take the initial oil film thickness as the initial value of the oil film thickness, divide the oil film on the plunger pair surface into m×n grid points, and calculate the Reynolds equation through a cyclic structure to obtain the initial value of the oil film pressure at each grid point; d. Using the Newton iteration method or the SOR iteration method, solve the balance equation of the distribution pair oil film pressure, surface force, and overturning moment to obtain the oil film thickness at each grid point of the plunger pair oil film, and output the minimum value of the plunger oil film thickness.

[0063] The second step is to calculate the oil film thickness of the slipper pair. The calculation process is as follows: a. Initialize the oil film thickness and the rate of change of oil film thickness of the slipper pair; b. Use real-time signals such as pressure and flow rate as boundary conditions, and simultaneously input the friction force of the plunger pair and the surface pressure of the plunger obtained from the dynamic calculation of the plunger pair as input to the dynamic equation of the slipper pair to solve for the surface force of the oil film of the slipper pair; c. Use real-time signals such as pressure and flow rate as calculation boundary conditions, take the initial oil film thickness as the initial value of the oil film thickness, divide the oil film on the surface of the slipper pair into m×n grid points, and solve the Reynolds equation through a cyclic structure to obtain the initial value of the oil film pressure at each grid point; d. Use the Newton iteration method or the SOR iteration method to solve the balance equation of the oil film pressure, surface force, and overturning moment of the distribution pair, obtain the oil film thickness at each grid point of the slipper pair, and output the minimum value of the oil film thickness of the slipper pair.

[0064] The third step is to calculate the oil film thickness of the distribution pair. The calculation process is as follows: a. Initialize the oil film thickness and oil film thickness change rate of the distribution pair; b. Use real-time signals such as pressure and flow rate as boundary conditions, and use the piston friction force and piston surface pressure obtained from the piston pair dynamics calculation as inputs to the distribution pair dynamic equation to calculate the overturning moment generated by the piston movement of the distribution pair, and solve for the forces on the oil film surface; c. Use real-time signals such as pressure and flow rate as calculation boundary conditions, use the initial oil film thickness as the initial value of the oil film thickness, divide the oil film on the distribution pair surface into m×n grid points, and use the Reynolds equation to solve for the initial value of the oil film pressure at each grid point through a cyclic structure; d. Use the Newton iteration method or the SOR iteration method to solve the balance equation of the oil film pressure, surface forces, and overturning moment of the distribution pair, obtain the oil film thickness at each grid point of the distribution pair oil film, and output the minimum value of the distribution pair oil film thickness.

[0065] The operating condition identification module determines whether the minimum oil film thickness of the plunger pair, the minimum oil film thickness of the slipper pair, and the minimum oil film thickness of the distribution pair are less than the threshold (the threshold is selected in the range of 0-20 micrometers). If the minimum oil film thickness of any of the three friction pairs is less than the threshold, a danger alarm signal is sent from the cloud to the PC and the name of the friction pair is output as the easily worn position.

[0066] The lifetime prediction method of the lifetime prediction module is implemented as follows:

[0067] The actual load conditions of the tunnel boring machine are relatively stable under the same geological conditions, so a constant stress load spectrum is used to conduct accelerated degradation tests.

[0068] A database of main drive plunger pumps was built by conducting multiple sets of constant stress accelerated degradation tests under various working conditions; noise reduction was performed on the collected vibration frequency signals and flow signals using signal noise reduction methods.

[0069] The signal wavelet packet energy, mean square frequency, kurtosis and other feature parameters are extracted. A 5% decrease in volumetric efficiency is used as the degradation threshold. The vibration feature parameters and pump volumetric efficiency are used as the training set to train the neural network and complete the establishment of the life prediction neural network.

[0070] The lifespan neural network is downloaded to a PC, and the real-time monitored vibration signals, rotational speed, outlet pressure, and flow signals are used as inputs to the neural network. By periodically processing and storing the onboard signals, the mean time to failure (MTTF) is estimated, and the remaining predicted lifespan is output by subtracting the running time.

[0071] The detailed explanations of the above embodiments are intended only to explain the present invention so as to facilitate a better understanding of the present invention. However, these descriptions should not be construed as limiting the present invention for any reason. In particular, the various features described in different embodiments can be arbitrarily combined with each other to form other embodiments. Unless there is an explicit description to the contrary, these features should be understood to be applicable to any embodiment, and not limited to the described embodiments.

Claims

1. A method for monitoring a plunger pump, characterized in that, The monitoring method includes: The pump body vibration frequency, outlet flow rate, outlet pressure, and internal pressure of the plunger pump are collected in real time. The oil film thickness of the internal friction pair of the plunger pump is calculated based on the pump body vibration frequency, outlet flow rate, outlet pressure, and pump body internal pressure. The oil film thickness of the friction pair in the plunger pump includes the oil film thickness of the plunger pair, the oil film thickness of the slipper pair, and the oil film thickness of the distribution pair. The calculation steps for the oil film thickness of the friction pair include: Initialize the oil film thickness and oil film thickness change rate of the friction pair; Using the outlet flow rate, the outlet pressure, and the internal pressure of the pump body as the calculation boundary conditions, the surface force of the friction pair oil film is solved. The initial oil film thickness is used as the initial value of the oil film thickness. The oil film of the friction pair is divided into m×n grid points. The Reynolds equation is calculated through a cyclic structure to obtain the initial value of the oil film pressure at each grid point. By using the oil film pressure and surface force and overturning moment balance equation of the friction pair, the oil film thickness at each grid point of the friction pair is obtained, and the minimum value of the oil film thickness is output as the oil film thickness of the friction pair. The operating condition of the plunger pump is determined based on the oil film thickness of the friction pair inside the plunger pump. When the oil film thickness of the friction pair is less than the threshold, the plunger pump is determined to be in a dangerous operating condition.

2. The monitoring method for a plunger pump as described in claim 1, characterized in that, A database of oil film thickness for friction pairs is established, including a reference thickness. The reference thickness is called up, and the operating condition of the plunger pump is monitored by comparing the oil film thickness of the friction pairs with the reference thickness.

3. The monitoring method for a plunger pump as described in claim 1, characterized in that, The monitoring method also includes predicting the service life of the plunger pump based on the vibration frequency and the outlet flow rate.

4. The monitoring method for a plunger pump as described in claim 3, characterized in that, A neural network for predicting the lifespan of a plunger pump is established. The pump's rotational speed, vibration frequency, outlet pressure, and outlet flow rate are input into the neural network. The neural network then estimates the remaining predicted lifespan of the plunger pump based on these parameters.

5. The monitoring method for a plunger pump as described in claim 4, characterized in that, The establishment of the plunger pump life prediction neural network includes: Accelerated degradation tests were conducted on the plunger pump using a constant stress load spectrum, and a plunger pump database was established. Extract the characteristic parameters of vibration frequency from the plunger pump database, and use the characteristic parameters and the pump volumetric efficiency of the plunger pump as a training set; The lifespan prediction neural network is established by training the neural network on the training set.

6. A monitoring system for a plunger pump, characterized in that, The monitoring system includes: The data acquisition module collects pump body vibration frequency, outlet flow rate, outlet pressure, and internal pressure of the pump body; The operating condition identification module is electrically connected to the data acquisition module. Based on the pump body vibration frequency, the outlet flow rate, the outlet pressure, and the pump body internal pressure, the operating condition identification module calculates the oil film thickness of the internal friction pair of the plunger pump. The oil film thickness of the friction pair in the plunger pump includes the oil film thickness of the plunger pair, the oil film thickness of the slipper pair, and the oil film thickness of the distribution pair. The calculation steps for the oil film thickness of the friction pair include: Initialize the oil film thickness and oil film thickness change rate of the friction pair; Using the outlet flow rate, the outlet pressure, and the internal pressure of the pump body as the calculation boundary conditions, the surface force of the friction pair oil film is solved. The initial oil film thickness is used as the initial value of the oil film thickness. The oil film of the friction pair is divided into m×n grid points. The Reynolds equation is calculated through a cyclic structure to obtain the initial value of the oil film pressure at each grid point. By using the oil film pressure and surface force and overturning moment balance equation of the friction pair, the oil film thickness at each grid point of the friction pair is obtained, and the minimum value of the oil film thickness is output as the oil film thickness of the friction pair. Then, based on the oil film thickness of the friction pair inside the plunger pump, the operating condition of the plunger pump is determined; When the oil film thickness of the friction pair is less than the threshold, the plunger pump is determined to be in a dangerous operating condition.

7. The monitoring system for the plunger pump as described in claim 6, characterized in that... The data acquisition module includes: An accelerometer is arranged on the pump casing and rear end cover of the plunger pump. The accelerometer is used to collect the vibration frequency of the pump body of the plunger pump. A pump outlet flow meter is arranged at the outlet of the plunger pump, and the pump outlet flow meter is used to collect the outlet flow of the plunger pump; A pump outlet pressure sensor is arranged at the outlet of the plunger pump to collect the outlet pressure of the plunger pump. A pump vent pressure sensor is installed at the vent of the plunger pump to collect the internal pressure of the pump body.

8. The monitoring system for the plunger pump as described in claim 6, characterized in that, The monitoring system also includes a life prediction module, which predicts the service life of the plunger pump based on the pump body vibration frequency and the outlet flow rate.

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