Mechanical rotating shaft electrical jump value tester

Abstract

The utility model provides an electrical jump value tester for a mechanical rotating shaft, and relates to the technical field of information electronics. The device comprises a whole machine hardware electric jump value detection system, an electric jump signal preprocessor, a data acquisition card, a miniature industrial personal computer and a touch screen, the whole machine hardware electric jump value detection system comprises an eddy current probe, an extension cable and a front-end device, and an output signal of the whole machine hardware electric jump value detection system is a voltage signal in direct proportion to the distance between the probe and the radial surface of a rotor. A voltage signal is output to the data acquisition card through the electric trip signal preprocessor, and the miniature industrial personal computer is in signal connection with the data acquisition card and the touch screen. The device is researched and developed aiming at the backward actual situation of the existing measurement means, has the advantages of low price, advanced technology, practical function and convenience in carrying, occupies a small place, is simple and convenient to operate, and is particularly suitable for occasions where small and medium-sized rotors need to be tested frequently.

Description

Technical Field

[0001] This utility model relates to the field of information and electronic technology, and in particular to a mechanical shaft electrical runout tester. Background Technology

[0002] Mechanical shafts, also known as rotors, are the core components of large turbine machinery. Rotor vibration faults are a major manifestation of turbine machinery failures. Finished rotors must undergo comprehensive inspection before being put into operation. Measuring mechanical runout and electrical runout is an important part of this inspection. According to the API 670 and API 612 standards set by the American Petroleum Institute, the combined value of mechanical runout and electrical runout from the journal retaining ring to the shaft end must not exceed 6.3 μm. Otherwise, it will affect the true value testing of normal parameters during unit operation.

[0003] Mechanical runout measurement is relatively simple. A dial indicator is fixed radially on the rotor, and the difference between the maximum and minimum values ​​(Δd) for each revolution is calculated; this difference is the mechanical runout value at that location. Electrical runout measurement requires an eddy current probe, an extension cable, a preamplifier, and a matching DC power supply. The voltage between the preamplifier's output terminal OUT and the common terminal COM is measured using a multimeter. The difference between the maximum and minimum values ​​(Δv) for one revolution of the rotor (one cycle) is recorded. Based on the relationship between displacement clearance and output voltage (1μm = 7.874mV), the electrical runout value is manually calculated. This process is cumbersome, involves numerous human factors, and has low reliability and accuracy, thus offering limited persuasiveness to users. Figure 1 Even the measurement methods commonly used in the past, such as structural diagrams.

[0004] With the development of my country's economic construction and increased exchanges with foreign countries, the importance of rotor electrical runout measurement in the industry is receiving more and more attention. However, compared with foreign countries, China's research on the causes and testing methods of electrical runout is still relatively backward. Imported testing equipment costs millions of dollars. Although it has many functions, it is bulky, complex to operate, and particularly unsuitable for frequent testing of small rotors. Currently, there is a lack of similar products in China. Utility Model Content

[0005] To address the shortcomings mentioned above, this utility model provides a mechanical shaft electrical runout tester, which was developed to address the limitations of existing measurement methods. It has the advantages of low price, advanced technology, practical functions, and portability. Moreover, it occupies little space and is easy to operate, making it particularly suitable for occasions where frequent testing of small and medium-sized rotors is required.

[0006] To address the aforementioned problems, this utility model provides a mechanical shaft electrical runout tester, comprising a whole-machine hardware electrical runout detection system, an electrical runout signal preprocessor, a data acquisition card, a micro industrial computer, and a touch screen. The whole-machine hardware electrical runout detection system includes an eddy current probe, an extension cable, and a preamplifier. Its output signal is a voltage signal proportional to the distance between the probe and the radial surface of the rotor. The voltage signal is output to the data acquisition card through the electrical runout signal preprocessor. The micro industrial computer is connected to both the data acquisition card and the touch screen.

[0007] Preferably, in the electrical jump signal preprocessor, the output voltage of the preamplifier enters the non-inverting input of U1 for 1x non-inverting amplification, the output of U1 is connected to a 1 / 2 voltage divider network, and then enters the voltage follower composed of U3 for buffer isolation. Finally, the detected voltage signal is output to the acquisition card by U4.

[0008] Preferably, the industrial control computer is connected to the signal input terminal of the touch screen via an Ethernet communication interface and a USB interface, respectively.

[0009] Preferably, the data acquisition card uses Ethernet to synchronize data, and it is a 16-bit resolution acquisition card.

[0010] Preferably, the industrial control computer is connected to a keyboard, mouse, USB flash drive, drives external printing devices, and can even transmit data files over a network.

[0011] Compared with the prior art, the present invention has the following advantages:

[0012] 1. This utility model was developed in response to the outdated nature of existing measurement methods. It has the advantages of low price, advanced technology, practical function, and easy portability. Moreover, it occupies little space and is easy to operate, making it particularly suitable for occasions where frequent testing of small and medium-sized rotors is required.

[0013] 2. This utility model integrates components such as the preamplifier, industrial computer, and display into a portable chassis, and features touch-screen human-computer interaction, external printer connection, and wireless networking. Through a measurement program developed based on the LabVIEW platform, this instrument achieves unprecedented functionality while remaining simple and practical. Attached Figure Description

[0014] Figure 1 This is a schematic diagram of an embodiment of the present utility model;

[0015] Figure 2 This is a schematic diagram of the electrical jump signal preprocessing circuit structure of an embodiment of this utility model. Detailed Implementation

[0016] To make the objectives, technical solutions and advantages of this utility model clearer, the present utility model will be further described in detail below with reference to the accompanying drawings and examples, but the examples given are not intended to limit the present utility model.

[0017] like Figure 1 and Figure 2 As shown, the embodiment of this utility model consists of five parts: a whole machine hardware electrical jump value detection system, a measurement signal preprocessor, a data acquisition card, a micro industrial control computer, and a touch screen. It also has a printer interface and a USB interface.

[0018] In this embodiment, the principle of electric shock detection is as follows: Turbine equipment widely uses the Bentley 3300xl eddy current sensor system for vibration monitoring of operating units. This instrument also uses this component in its design and manufacturing, improving reliability, applicability, and user understanding. The electric shock detection section consists of an eddy current probe, an extension cable, and a preamplifier. Its output signal is a voltage signal proportional to the distance between the probe and the radial surface of the rotor, also known as the gap voltage. The system requires that this gap be correctly adjusted when installing the probe to ensure measurement accuracy within the linear relationship range.

[0019] In this embodiment, as can be seen from the working principle of the eddy current sensor system, the magnitude of the output voltage signal of the measurement system is related not only to the geometry of the rotor surface but also to the properties of the rotor surface material. In particular, the uneven residual magnetism left during the rotor processing will cause irregular fluctuations in the output voltage. This fluctuation is not due to vibration caused by the rotor's actual imbalance, which is called "electric jump" in the industry. Excessive electric jump will inevitably affect the normal vibration monitoring of the operating unit and may even cause alarms and interlock shutdowns. Such rotors must be demagnetized and retested before they can be put into operation.

[0020] In this embodiment, the electrical runout detected by the eddy current probe is actually a comprehensive runout that includes mechanical runout. For rotors with excessively large electrical runout values, the mechanical runout value should also be measured to determine and differentiate the cause of the excessive electrical runout. The electrical runout value is represented by the physical quantity Δd, where the mechanical runout value can be directly given, while the electrical runout value must be calculated using the relationship between the system's displacement and voltage. Below is a record of the electrical runout test conducted on a certain rotor by the Shenyang Blower Works Group Gear Works, which clearly illustrates the relationship between mechanical runout and electrical runout. See the table below:

[0021]

[0022] In this embodiment, the electrical jump signal preprocessing circuit: Generally, the voltage input range of an A / D acquisition card is mostly within ±10V. However, when detecting an electrical jump, the gap of the eddy current probe needs to be adjusted to a specified linear range, such as 1.5mm. At this time, the gap voltage it reflects is about 12V, which exceeds the maximum range of the acquisition card. In addition, in order to ensure that the AD circuit of the acquisition card has a relatively large margin and high accuracy, the voltage signal must be quantitatively attenuated.

[0023] In this embodiment, the output voltage of the preamplifier enters the non-inverting input of U1 for 1x non-inverting amplification, the output of U1 is connected to a 1 / 2 voltage divider network, and then enters the voltage collector composed of U3 for buffering and isolation. Finally, the detected voltage signal is output to the acquisition card by U4. The function of U4 is to reverse the transformed voltage signal to facilitate the AD acquisition card to receive and perform mathematical calculations.

[0024] In this embodiment, the data acquisition card is an Ethernet synchronous data acquisition card. Since the rotating shaft moves very slowly during testing, a high sampling rate is not required. However, to ensure sufficient measurement accuracy, a high resolution is required for the acquisition card. A 16-bit resolution acquisition card is sufficient; a higher resolution would be wasteful. The acquisition card parameters are shown in the table below:

[0025] model Power supply / operating current DC12V / 100mA Hardware and software platforms PC / ARM platform, Windows / Linux system Supported programming languages Supports C, LabVIEW, MATLAB, etc. Maximum resolution 16-bit (65535) Maximum sampling rate 40KSPS AI channel number Single-ended 8ch, differential 4ch AI input range -10V~10V(PGA=1),-5V~5V(PGA=2) Programmable Gain PGA=1,2 Maximum error <0.05％

[0026] In this embodiment, the industrial computer: In order to reduce the size of this instrument, a mini model with a size of 12*17*40cm was specially selected as the core component of the machine. Its powerful functions are fully utilized to achieve the required performance indicators of this instrument. Through the connection with the touch screen, the test operation can be performed clearly and simply on the human-machine interface. The Labwiew configuration screen developed based on the Windows 7 system runs without any pressure.

[0027] In this embodiment, the instrument also brings out the Ethernet communication interface and USB interface of the industrial control computer to the panel, and can also connect to a keyboard, mouse, mobile USB flash drive, drive external printing devices, and even transmit data files over the network.

[0028] The key parameters of an industrial computer are as follows:

[0029]

[0030]

[0031] In this embodiment, the instrument is used as follows:

[0032] (a) General testing methods:

[0033] 1. Connect the probe and fix it on the bracket. Make sure the probe end face is perpendicular to the rotor shaft centerline. While adjusting the gap between the probe and the rotor, observe the "gap voltage value" displayed on the touch screen until the reading is between 9.5V and 10.5V. This is the optimal measurement gap: 1.2-1.3mm. If necessary, you can use a feeler gauge to verify.

[0034] 2. Manually rotate the rotor one or two revolutions and observe the change in the "gap voltage" value. It should be a small change to one decimal place before proceeding to the next step of formal measurement.

[0035] 3. Press the "Start" button. The "Electric Voltage" display will show a millivolt value with one decimal place. It may be positive or negative. While rotating the rotor, observe the changes in the "Electric Voltage". When the maximum and minimum values ​​(including the negative value with the largest absolute value) appear, press the "Maximum" and "Minimum" buttons respectively. The corresponding data will be recorded and displayed in the corresponding display window.

[0036] 4. The above process of confirming the "maximum" and "minimum" values ​​can be repeatedly modified until the results are satisfactory. Then, press the "confirm" button. The software program will calculate the difference between the maximum and minimum values ​​and convert the physical quantities to obtain the electrical jump value. The computer will record and save this value and display it in the corresponding "electrical jump value μm" window.

[0037] (II) Advanced testing methods:

[0038] 1. First, mark the journal of the rotor to be tested with 16 equal parts, using Arabic numerals from 0 to 15.

[0039] 2. Fix the eddy current probe at the 0 position and adjust the probe gap to about 10V.

[0040] 3. Rotate the rotor one or two revolutions and observe the change in the "gap voltage" value. If it is not very large (it should change to two decimal places), it means that the test platform foundation is normal and the test system equipment is fixed and connected normally, and you can proceed to the next step of formal measurement.

[0041] 4. Rotate the rotor back to the probe's 0 position, press the "Start" button, and the "Electric Voltage" display will show a millivolt value with one decimal place. It may be a very small positive number, a negative number, or zero, all of which are normal.

[0042] 5. Press the confirmation button to record the 0th digit of the electrical jump value. Rotate the rotor to position 1 of the probe and press the confirmation button again to record the 1st digit of the electrical jump value. Rotate the rotor to position 15 of the probe and press the confirmation button again to record the 15th digit of the electrical jump value. The recorded value is the last digit of the electrical jump value.

[0043] 6. Press the Fit button, and the system will perform curve fitting based on the data of the 16 recorded points to complete the drawing of the electric jump value unfolded graph and polar coordinate graph at each angle.

[0044] This embodiment replaces the traditional measurement method of manual operation and visual calculation, realizing a leap forward in the measurement of electrical runout values ​​of small and medium-sized rotors towards intelligence, lightweight design, accuracy, and reliability. It has high practical value and is of great significance for strengthening product quality and improving product performance. The main effects achieved are:

[0045] 1. The main equipment of the measurement system is integrated into an "all-in-one machine", which is easy to carry and operate.

[0046] 2. Two measurement methods are provided. In particular, the advanced method uses segmented testing to locate and provide the electrical jump value. The electrical jump curve is plotted using a fitting method, which improves the technical level of the instrument and helps technicians to better analyze and handle problems.

[0047] 3. The human-machine interface plays a full role in this instrument. Display windows and virtual buttons are arranged in an orderly manner according to the measurement process, creating an excellent user environment that is easy and quick to operate and provides clear numerical values.

[0048] 4. This instrument was successfully developed using the popular labWIEW software. LabWIEW plays a significant role in data acquisition, processing, and storage, especially for irregular electrical jump values ​​and changes in measurement units. It also generates a virtual instrument interface on the screen that is identical to that of a traditional instrument panel.

[0049] 5. Instrument parameters:

[0050] A. External dimensions: 41.5cm*38.2cm*22.5cm;

[0051] B. Total weight: 6.8Kg;

[0052] C. Operating conditions: IP62 protection, temperature 0-35℃, humidity ≤90%;

[0053] D. Input power supply: DC12V / 7.5A;

[0054] E. Measurement range: -50μm to +50μm;

[0055] F. Measurement accuracy: 0.3μm;

[0056] G. Resolution: 0.1μm.

[0057] Those skilled in the art can connect all electrical components and their compatible power supplies in this case via wires, and should select appropriate controllers according to actual conditions to meet control requirements. The specific connection and control sequence, and the sequential operation order between each electrical component to complete the electrical connection, are well-known technologies in the field, and will not be described further regarding electrical control.

[0058] Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of the present invention.

[0059] In the description of this specification, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc., indicating the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, are only for the convenience of describing the technical solution of this patent and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation on this patent application.

[0060] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this patent application, "a plurality of" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0061] In this specification, unless otherwise expressly specified and limited, the terms "installation," "connection," "joining," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components, unless otherwise expressly limited. Those skilled in the art can understand the specific meaning of the above terms in this specification according to the specific circumstances.

[0062] In this specification, unless otherwise expressly specified and limited, "above" or "below" the second feature can mean that the first and second features are in direct contact, or that the first and second features are in indirect contact through an intermediate medium. Furthermore, "above," "over," and "on top" of the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0063] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0064] Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of the present invention.

Claims

1. A mechanical shaft electrical runout tester, characterized in that, The system includes a whole-machine hardware electrical jump value detection system, an electrical jump signal preprocessor, a data acquisition card, a micro industrial computer, and a touch screen. The whole-machine hardware electrical jump value detection system includes an eddy current probe, an extension cable, and a preamplifier. Its output signal is a voltage signal proportional to the distance between the probe and the radial surface of the rotor. The voltage signal is output to the data acquisition card through the electrical jump signal preprocessor. The micro industrial computer is connected to the data acquisition card and the touch screen respectively.

2. The mechanical shaft electrical runout tester as described in claim 1, characterized in that, In the electrical jump signal preprocessor, the output voltage of the preamplifier enters the non-inverting input of U1 for 1x non-inverting amplification, the output of U1 is connected to a 1 / 2 voltage divider network, and then enters the voltage follower composed of U3 for buffering and isolation. Finally, the detected voltage signal is output to the acquisition card by U4.

3. The mechanical shaft electrical runout tester as described in claim 2, characterized in that, The industrial control computer is connected to the signal input terminal of the touch screen via an Ethernet communication interface and a USB interface, respectively.

4. The mechanical shaft electrical runout tester as described in claim 3, characterized in that, The data acquisition card uses Ethernet to synchronize data, and it is a 16-bit resolution acquisition card.

5. The mechanical shaft electrical runout tester as described in claim 4, characterized in that, The industrial computer connects to a keyboard, mouse, USB flash drive, drives external printing devices, and can even transmit data files over a network.

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