Intelligent bolt elongation measuring system

Abstract

The invention relates to an intelligent bolt elongation measuring system, which comprises a bolt group, a hydraulic stretcher and a displacement sensor, the bolt group comprises a bolt, and a nut and a sleeve which are arranged outside the bolt; the hydraulic tensioner comprises a tensioner. The sleeve and the nut are sequentially installed on the upper section of the bolt, the hydraulic tensioner and other tools are installed on the nut, and the upper section of the bolt is forced to stretch through the hydraulic tensioner and is increased along with bolt stretching along with pressure rise of a pump station till stretching meets the design locking requirement. According to bolt elongation, elongation data are collected through the contact type displacement sensor, and the change value of the bolt elongation caused by the change of the pressure value of the hydraulic pump in the locking process of the bolt set can be monitored in real time till the designed elongation value is reached.

Description

Technical Field

[0001] The invention relates to an intelligent bolt elongation measuring system. Background Art

[0002] The bolts on the dividing surface of the steam turbine and gas engine in the power plant are used to seal the upper and lower cylinders together to ensure the normal operation of the internal components of the cylinder body and prevent the leakage of high-temperature steam from causing safety risks. In actual operation, if the bolt locking force is too large and the bolt elongation is too long, the bolt life will be shortened, and the bolts will break and fall out when the unit is running. If the bolt locking force is too small and does not reach the designed locking value, the nuts will easily loosen when the unit is running, and air leakage will occur on the dividing surface of the upper and lower cylinders, resulting in erosion of the dividing surface and damage. The locking process in the above operation cannot detect in real time whether the bolt locking force is too large or too small, and can only be indirectly detected afterwards by means of tapping, measurement, etc. If it is unqualified, it needs to be disassembled and locked repeatedly, wasting assembly time.

[0003] At present, the locking force of the center-split bolt group of steam turbines and gas turbines is often based on the nut rotation arc length or rotation angle. The bolt group locking is divided into two stages: initial tightening and final tightening. Due to different locking methods and bolt materials, the nut rotation arc length or rotation angle cannot be accurately measured, nor can it be accurately reflected on the bolt itself. Since the changes in the bolt locking process cannot be tracked in real time, the bolt group locking force will fluctuate beyond the design value, thus affecting the unit's operating safety. Summary of the invention

[0004] The technical problem to be solved by the present invention is to provide an intelligent bolt elongation measurement system, which can monitor in real time the change in the bolt elongation caused by the change in the hydraulic pump pressure value during the tightening process of the bolt group, and finally achieve the bolt elongation in line with the design value range at one time to meet the normal operation of the unit.

[0005] The technical solution adopted by the present invention is: A bolt intelligent elongation measurement system, comprising a bolt group, a hydraulic stretcher and a displacement sensor; The bolt group includes a bolt, a nut and a sleeve arranged outside the bolt; The hydraulic stretcher comprises a stretcher; A threaded hole is provided in the middle of the inner shell of the tensioner, the upper end of the bolt is connected to the inner shell by a thread, the lower end of the outer shell of the tensioner cooperates with the sleeve, the nut is located inside the outer shell and is arranged above the sleeve, and the displacement sensor is fixedly installed at the top position of the hydraulic tensioner, and its contact passes through the hydraulic tensioner and is pressed against the upper end face of the bolt.

[0006] Furthermore, a driving ring is fixedly installed above the nut, and the nut can be rotated around the thread on the bolt by turning the driving ring.

[0007] Furthermore, the contact of the displacement sensor is eccentrically arranged with respect to the upper end surface of the bolt.

[0008] Furthermore, a stretching head is installed on the upper end of the bolt, and the upper end of the stretching head is threadedly connected to the inner shell of the stretcher. A through hole is provided at the axial position of the stretching head, and the displacement sensor passes through the through hole and is pressed against the upper end surface of the bolt.

[0009] Furthermore, an end cover is provided on the upper end surface of the bolt, and the contact of the displacement sensor is pressed against the end cover.

[0010] Furthermore, a hydraulic pump station is connected to the hydraulic stretcher, and a pressure sensor is used to collect the working gauge pressure of the hydraulic pump station and output it to the PLC through the serial port line. The displacement value of the displacement sensor is transmitted to the PLC through the hub.

[0011] Furthermore, the hub is a four-way hub, and the hydraulic pump station is an ultra-high pressure electric hydraulic pump station with four-point control, which can meet the simultaneous stretching operations of four groups of hydraulic stretchers.

[0012] The positive effects of the present invention are: The present invention sequentially installs a sleeve and a nut on the upper section of the bolt, and installs a hydraulic tensioner and other tooling on the nut. The hydraulic tensioner forces the upper section of the bolt to elongate, and the bolt elongation increases with the increase of the pump station pressure until the elongation meets the design locking requirements. The bolt elongation collects the elongation data through a contact displacement sensor, and transmits the data to the PLC host. It can monitor in real time the change in the bolt elongation caused by the change in the hydraulic pump pressure value during the locking process of the bolt group until the design elongation value is reached, so that the bolt elongation meets the design value range at one time, and meets the normal operation of the unit. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 This is a schematic diagram of the structure of Embodiment 1 of the present invention; Figure 2 For the present invention Figure 1 Middle AA section; Figure 3 This is a schematic diagram of the structure of Embodiment 2 of the present invention; Figure 4 For the present invention Figure 3 Middle BB section; Figure 5 It is the principle diagram of the system of the present invention; Figure 6 This is a diagram showing the sequence of the bolts of the present invention being installed in a steam turbine. DETAILED DESCRIPTION

[0014] The invention discloses an intelligent bolt elongation measuring system, which is mainly used for measuring, displaying and controlling parameters such as elongation, pressure and the like of a bolt group 2 at a center plane position of a steam turbine, a gas engine and the like when being locked.

[0015] Example 1 As attached Figure 1 , 2 As shown in , 5 and 6 , the measurement system disclosed in this embodiment is suitable for an environment where the operating space around the bolt group 2 is unlimited. It includes the bolt group 2 , the hydraulic tensioner 3 and the displacement sensor 6 .

[0016] The upper cylinder body and the lower cylinder body are buckled and sealed at the dividing surface of the steam turbine 1 unit by means of a bolt group 2. The bolt group 2 includes a bolt 21, a nut 22 and a sleeve 23. The lower section of the bolt 21 is screwed into the lower cylinder body of the steam turbine unit. The sleeve 23 is located at the upper section of the bolt 21 and its lower end face is in contact with the end face of the upper cylinder body. The nut 22 is located above the sleeve 23 and is threadedly connected to the bolt 21. The nut 22 is tightened by a tool, and the sleeve 23 presses the end face of the upper cylinder body to achieve the tightness of the dividing surface between the upper cylinder body and the lower cylinder body. Preferably, the bolt group 2 is evenly distributed on both sides of the cylinder body axis (such as the attached Figure 6 As shown in the figure), the locking sequence is #1, #2, #3, #4, #5, #6, #7, #8, #9, #10... and they are locked symmetrically in sequence to ensure that the forces on both sides of the upper and lower cylinder bodies are uniform and the deformation is consistent.

[0017] A driving ring 34 is fixedly mounted on the upper end surface of the nut 22 . The driving ring 34 can be turned to rotate the nut 22 around the thread on the bolt 21 , thereby achieving the locking and disassembly actions of the nut 22 .

[0018] The hydraulic tensioner 3 includes a tensioner 31, which includes an inner shell and an outer shell. An internal thread is provided at the center of the inner shell. The upper thread of the bolt 21 is screwed with the internal thread to achieve axial positioning. The displacement sensor 6 is arranged on the top surface of the hydraulic tensioner 3 and is fixed by a screw 35 to prevent the sensor from axial movement. After the displacement sensor 6 passes through the hydraulic tensioner 3, its contact is pressed against the upper end surface of the bolt 21. Preferably, the contact is directly pressed against the upper end surface of the bolt 21 in an eccentric manner to avoid the center hole of the bolt.

[0019] A hydraulic pump station 4 is connected to the housing, and a pressure sensor 5 is used to collect the working gauge pressure of the hydraulic pump station 4 .

[0020] When in use, the hydraulic pump station 4 injects oil into the tensioner 31 through the high-pressure oil pipe. Under the pressure of the oil pressure, the inner shell and outer shell of the tensioner 31 are axially disengaged, and the outer shell is pressed against the upper end face of the sleeve 23, while the lower end face of the sleeve 23 is pressed against the upper cylinder end face of the steam turbine 1. Since the upper cylinder end face of the steam turbine 1 is fixed, the outer shell of the tensioner 31 is axially fixed, and the inner shell is disengaged upward in the axial direction under the influence of the oil pressure. The inner shell is directly screwed on the upper section of the bolt 21 by threading, and the inner shell moves upward in the axial direction while pulling the bolt 21 to extend upward. The contact of the displacement sensor 6 fixed to the outer shell of the tensioner 31 is pressed against the upper end face of the bolt 21. The contact will cause the value displayed on the screen of the displacement sensor 6 to change continuously as the bolt 21 extends upward, and can be transmitted to the hub 7 through the serial port line.

[0021] The hub 7 is a four-way hub, which outputs the displacement data to the PLC8 host through the RS232 port or RS485 port; the pressure sensor 5 takes the working gauge pressure of the hydraulic pump station 4 and outputs it to the PLC8 host through the serial port line. Preferably, the hydraulic pump station 4 is an ultra-high pressure electric hydraulic pump station with four-point control to meet the simultaneous stretching operation of four groups of hydraulic tensioners 3. The human-machine interface 9 of the terminal receives the data transmitted by the PLC8 host and can dynamically display the parameters such as the bolt group 2 number, the elongation of the bolt group 2, the elongation curve of the bolt group 2, the pressure value of the bolt group 2, the pressure curve of the bolt group 2 and the corresponding measured curve after programming, and supports PLC programming, uploading and downloading, debugging of PLC programs and data output by plugging in a printer.

[0022] Example 2 The measurement system disclosed in this embodiment is suitable for an environment where the operating space around the bolt group 2 is small, and its structure is improved on the basis of the first embodiment.

[0023] On the basis of Example 1, the structures of the stretching head 32 and the end cover 33 are added. Figure 3 , 4 As shown, the stretching head 32 is located between the bolt 21 and the inner shell of the stretcher 31, and its upper end is screwed with the internal thread of the inner shell to achieve axial positioning, and the lower end is connected to the upper end of the bolt 21 through a thread. The end cover 33 is installed in the center hole of the top surface of the bolt 21 through a thread, and is pressed by the stretching head 32 to ensure that the axial positions of the stretching head 32, the end cover 33 and the bolt 21 are relatively fixed. A through hole is provided at the axial center position of the stretching head 32, and the displacement sensor 6 passes through the through hole and is pressed against the end cover 33 installed on the upper end surface of the bolt 21.

[0024] Preferably, in order to meet the design value of the stretching length of the bolt group 2, the oil pressure area of ​​the hydraulic tensioner 3 should be matched with its stretching force. In an environment where the operating space around the bolt group 2 is small, the tensioner 31 can be improved from single-stage stretching to double-stage stretching, so as to double the stretching force in a cramped environment.

[0025] When in use, the hydraulic pump station 4 injects oil into the tensioner 31 through the high-pressure oil pipe. Under the pressure of oil pressure, the inner shell and outer shell of the tensioner 31 are axially disengaged, and the outer shell is pressed against the upper end face of the sleeve 23, while the lower end face of the sleeve 23 is pressed against the upper cylinder end face of the steam turbine 1. Since the upper cylinder end face of the steam turbine 1 is fixed, the outer shell of the tensioner 31 is axially fixed, and the inner shell is disengaged upward in the axial direction under the influence of oil pressure. The inner shell is screwed into the tensioning head 32 by threading, and the tensioning head 32 is screwed into the upper section of the bolt 21 by threading. The inner shell moves upward in the axial direction while pulling the bolt 21 to extend upward. The contact of the displacement sensor 6 fixed to the outer shell of the tensioner 31 is pressed against the end cover 33 screwed with the upper end face of the bolt 21. The contact will cause the value displayed on the screen of the displacement sensor 6 to change continuously as the bolt 21 and the end cover 33 extend upward, and can be transmitted to the hub 7 through the serial port line. The hub 7 can simultaneously receive the data change values ​​transmitted by the contact compression bolt groups 2 of the four groups of displacement sensors 6, for example, it can simultaneously monitor the elongation change values ​​of the #1, #2, #3, and #4 bolt groups, and further realize the completion of the simultaneous locking action of the #1, #2, #3, and #4 bolt groups, thereby greatly shortening the assembly time of the bolt group 2 on the turbine 1 and improving the on-site assembly efficiency.

[0026] In this embodiment, the hydraulic pump station 4 pumps high-pressure oil to the hydraulic tensioner 3, driving the bolt 21 screwed with the tensioning head 32 to achieve upward extension, and the contact of the displacement sensor 6 transmits the extension change value to the hub 7 and outputs it to the PLC 8. At the same time, the pressure sensor 5 monitors the pressure value of the working pump oil of the hydraulic pump station 4 and outputs it to the PLC 8. The above monitoring data is summarized and programmed and displayed on the human-machine interface 9, and the visual indicator parameters are selected through the manual touch interface.

[0027] The present invention has the function of real-time monitoring data, and can realize real-time monitoring of parameters such as the elongation and pressure of the bolt group, ensure that the bolt locking is qualified at one time, meet the design requirements, and eliminate the bolt tightening force error. High precision avoids the rework caused by the traditional post-measurement method that finds that the bolt locking force does not meet the design value range. It has the ability to measure the tension of four groups of bolts at the same time. According to the customer's construction period requirements, the four-way hub is replaced with an eight-way hub or the main hub and sub-hub are used for hierarchical connection, which can meet the doubled number of tension bolts that can be measured at the same time, and double the efficiency of traditional single-piece bolt locking.

[0028] In order to facilitate on-site operations, key components such as the hydraulic pump station 4, pressure sensor 5, hub 7, PLC 8, and human-machine interface 9 are placed in an integrated cabinet to facilitate on-site staff to push, pull, and move.

[0029] In the traditional method, it is impossible to monitor the elongation of the bolt in real time, so it is unknown whether the elongation is qualified after the locking action is completed. Through the dynamic monitoring method of the process of the present invention, the excessive or insufficient elongation of the bolt is compensated, the work of repeated stretching is reduced, and the bolt is locked once and the elongation meets the design value. Real-time monitoring of the elongation of the bolt is an efficient and modern means to control the locking force to meet the design value.

[0030] The present invention can monitor in real time the change in the bolt elongation caused by the change in the hydraulic pump pressure value during the locking process of the bolt group until the designed elongation value is reached, and the measurement accuracy reaches 0.001. The mechanical contact measurement method is adopted, and the contact of the displacement sensor 6 presses the end face of the bolt 21, and the elongation can be monitored in real time as the bolt 21 elongates. The deformation value of the bolt elongation is collected by the displacement sensor and transmitted to the hub in real time. After being processed by the PLC host, it is output to the human-machine interface, realizing the visualization and dynamic transformation of the measurement data, recording the data process value, and satisfying that the bolt locking meets the elongation design value. At the same time, a manual interface is set up to control the oil pressure value through the touch screen operation, and select to view the dynamic curve of the elongation of the specified bolt group, so as to realize human-computer interaction.

[0031] The supporting hardware is flexible and can be designed according to the size of the bolt installation space to ensure that the tension provided by the single-stage or multi-stage tensioner meets the elongation deformation of the bolt.

[0032] The bolt locking achieved by the present invention satisfies the requirement of uniform force on the bolt and meets the bolt installation standard. Compared with the traditional method of judging whether the nut is locked by sound identification through a small hammer, or judging the bolt elongation by using a dial indicator or a homemade measuring rod afterwards, the present invention is more intelligent, visual, and highly accurate, and can meet the monitoring and control requirements of personnel from all parties.

[0033] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit the same. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that the technical solutions described in the aforementioned embodiments may still be modified, or some of the technical features thereof may be replaced by equivalents. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A bolt intelligent elongation measurement system, characterized in that It comprises a bolt group (2), a hydraulic tensioner (3) and a displacement sensor (6); The bolt assembly (2) comprises a bolt (21) and a nut (22) and a sleeve (23) arranged outside the bolt (21); The hydraulic stretcher (3) comprises a stretcher (31); A threaded hole is provided in the middle of the inner shell of the stretcher (31); the upper end of the bolt (21) is connected to the inner shell by a thread; the lower end of the outer shell of the stretcher (31) cooperates with the sleeve (23); the nut (22) is located inside the outer shell and is arranged above the sleeve (23); the displacement sensor (6) is fixedly installed at the top position of the hydraulic stretcher (3); and its contact passes through the hydraulic stretcher (3) and is pressed against the upper end surface of the bolt (21).

2. The intelligent bolt elongation measurement system according to claim 1 is characterized in that A driving ring (34) is fixedly mounted above the nut (22), and the nut (22) can be rotated around the thread on the bolt (21) by turning the driving ring (34).

3. The intelligent bolt elongation measurement system according to claim 1 is characterized in that The contact of the displacement sensor (6) is eccentrically arranged with respect to the upper end surface of the bolt (21).

4. The intelligent bolt elongation measurement system according to claim 1 is characterized in that A stretching head (32) is mounted on the upper end of the bolt (21). The upper end of the stretching head (32) is threadedly connected to the inner shell of the stretcher (31). A through hole is provided at the axial center of the stretching head (32). The displacement sensor (6) passes through the through hole and is pressed against the upper end surface of the bolt (21).

5. The intelligent bolt elongation measurement system according to claim 4 is characterized in that An end cover (33) is provided on the upper end surface of the bolt (21), and a contact of the displacement sensor (6) is pressed against the end cover (33).

6. The intelligent bolt elongation measurement system according to claim 1 is characterized in that A hydraulic pump station (4) is connected to the hydraulic tensioner (3). The working gauge pressure of the hydraulic pump station (4) is collected by a pressure sensor (5) and output to a PLC (8) via a serial port line. The displacement value of the displacement sensor (6) is transmitted to the PLC (8) via a hub (7).

7. The intelligent bolt elongation measurement system according to claim 6 is characterized in that The hub (7) is a four-way hub, and the hydraulic pump station (4) is an ultra-high-pressure electric hydraulic pump station with four-point control, which can meet the requirements of simultaneous stretching operations of four groups of hydraulic stretchers (3).

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