Abrasion loss on-line detection method and device

Abstract

The invention discloses an on-line abrasion loss detection method and device, and belongs to the technical field of abnormal monitoring of medium-speed coal mills, the device comprises a proximity switch and induction blocks, and the induction blocks are arranged on a grinding roller in a circle at equal intervals and rotate along with the grinding roller. The method comprises the steps that in the rotating operation process of the grinding roller, the induction blocks rotate along with the grinding roller, a signals are sent to the control system when the proximity switch encounters a induction blocks every time the grinding roller rotates by a circle, the control system counts the number of the signals received within one minute, and the rotating speed of the grinding roller is calculated according to a formula; once the rotating speed of the grinding roller is 0, the grinding roller is locked. And based on the above, recording the rotating speed of the grinding roller at the beginning of the set period and the rotating speed of the grinding roller at the end of the set period, and calculating the single-side abrasion loss of the grinding roller through a formula. The locking condition of the grinding roller can be found in time, shutdown check and problem finding can be immediately carried out, and a bearing and a roller tire in the grinding roller can be prevented from being damaged; and the abrasion loss of the grinding roller in the coal mill can be monitored at any time under the condition that the machine is not stopped.

Description

Technical Field

[0001] This invention mainly relates to the field of abnormal monitoring technology for medium-speed coal mills, specifically to an online wear detection method and device. Background Technology

[0002] Medium-speed coal mills are key equipment in the pulverizing system of thermal power plants. They grind granular raw coal into coal powder of a certain fineness, which is then sent to the boiler for combustion to generate electricity and heat. Existing medium-speed coal mills have the following disadvantages during operation:

[0003] Disadvantage 1: The grinding rollers and grinding bowl liners are grinding components that come into direct contact with the raw coal. As the coal mill runs, the grinding rollers will become thinner and thinner due to wear. However, since existing coal mills do not have online detection methods, in order to check the amount of wear, it is necessary to stop the machine periodically and have workers enter the coal mill for manual inspection. This not only affects production, but is also time-consuming, labor-intensive, and expensive.

[0004] Disadvantage 2: The grinding roller is a key component of a medium-speed coal mill. It contains precision parts, and the wear-resistant material used for the outer roller is expensive, resulting in a high unit price for the grinding roller. Existing medium-speed coal mills cannot detect the grinding roller speed. If the grinding roller seizes up for some reason, continued use will damage the bearings and roller sheath inside the roller, resulting in significant losses. Summary of the Invention

[0005] The present invention addresses the problem that existing technical solutions are too simplistic and provides a solution that is significantly different from existing technologies. It mainly provides an online wear detection method and device to solve the technical problems mentioned in the background art, such as the time-consuming and labor-intensive inspection of grinding roller wear and the inability to detect seizing abnormalities in a timely manner.

[0006] The technical solution adopted by the present invention to solve the above-mentioned technical problems is as follows:

[0007] A method for online wear detection includes the following steps:

[0008] S1. Assemble an online wear detection device, including setting a induction blocks arranged in a circle at equal intervals on the rotating part of the grinding roller, and installing a proximity switch on the grinding roller shaft for being triggered by the induction blocks;

[0009] S2. During the operation of the grinding roller, the sensing block rotates accordingly. For each rotation of the grinding roller, the proximity switch encounters a sensing blocks, and the proximity switch sends a signals to the control system. The control system counts the number of signals received within one minute as b.

[0010] S3. The control system calculates the grinding roller speed n0 according to formula (1) and displays the result directly on the user's display screen.

[0011] n0 = b / a (1)

[0012] S4. Users can judge whether the operation of the coal mill is normal by monitoring the rotation speed. Once the rotation speed n0 of the grinding roller is 0, it means that the grinding roller has seized up and the machine needs to be stopped immediately for maintenance.

[0013] S5. Based on steps S1-S3, the control system records the grinding roller speed n1 at the beginning of the set cycle and the grinding roller speed n2 at the end of the cycle.

[0014] S6. The control system calculates the wear amount x on one side of the grinding roller according to formula (2) and displays the calculation result directly on the user's display screen.

[0015] x=D*N*(1 / n1-1 / n2) (2)

[0016] Where D represents the diameter of the meshing point; N represents the grinding speed;

[0017] S7. Users can judge the wear condition of the grinding roller by monitoring the wear on one side of the grinding roller. When the wear reaches the level that affects the normal operation of the grinding roller, the machine should be stopped for inspection and replacement of parts.

[0018] As an optimization of the above scheme, in step S1, a switch assembly is also installed on the grinding roller shaft and electrically connected to a time relay and an alarm. The switch assembly includes a first switch and a second switch; the first switch and the second switch are connected in parallel and connected in series with the coil of the time relay, and the action switch of the time relay is connected in series with the alarm.

[0019] In step S2, during the normal rotation of the grinding roller, the first and second switches are intermittently closed. The closing time of the first and second switches does not meet the timing requirement of the time relay, so the time relay cannot activate the action switch and thus the alarm will not be activated. When a seizure occurs, one of the first and second switches is closed, and the time relay starts timing. When the time relay reaches the time requirement, it will activate the action switch and activate the alarm, which can more promptly remind the management and operation personnel.

[0020] The present invention also provides an online wear detection device, applied to the above-mentioned online wear detection method, comprising a plurality of sensing blocks arranged in a circle at equal intervals on the rotating part of the grinding roller and a proximity switch mounted on the grinding roller shaft. The distance between the sensing blocks and the proximity switch and the axis of the grinding roller shaft is equal. One end of the proximity switch facing away from the sensing end is connected to a cable, and the other end of the cable is connected to the user's control system to transmit the signal of the proximity switch.

[0021] Preferably, the end face of the sensing block facing the proximity switch is 3-5mm away from the sensing end of the proximity switch.

[0022] Specifically, the cable is connected to the proximity switch via a cable connector. A connecting sleeve is fitted around the outside of the proximity switch. The cable connector is closed at one end of the connecting sleeve. The connecting sleeve is closed onto the grinding roller shaft and locked with a nut. The sensing end of the proximity switch is exposed outside the connecting sleeve.

[0023] Furthermore, it also includes a switch assembly, a time relay, and an alarm. The switch assembly includes a fixed block fixedly connected to the grinding roller shaft and a movable block connected to the fixed block via a spring. The portion of the movable block that contacts the sensing block is set as an inclined surface. The switch assembly also includes a first contact and a second contact constituting a first switch, and a third contact and a fourth contact constituting a second switch. The first contact and the third contact are respectively fixedly connected to the fixed block, and the second contact and the fourth contact are respectively fixedly connected to the movable block. The first contact and the second contact are respectively located on opposite sides of the fixed block and the movable block, and the fourth contact is located on the side of the third contact facing away from the movable block. The first switch and the second switch are connected in parallel and connected in series with the coil of the time relay. The actuation switch of the time relay is connected in series with the alarm.

[0024] Preferably, a guide rod is fixed on the fixed block and inserted into the moving block, and the spring is sleeved on the guide rod.

[0025] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0026] (1) The present invention introduces an online monitoring method for wear and grinding roller speed in a coal mill. The online detection of grinding roller speed can monitor the grinding roller speed inside the coal mill at any time. If the grinding roller is stuck, the user can detect the grinding roller stuck in time by monitoring the speed value to 0, and immediately stop the machine to check and find the problem, which can avoid damage to the bearings and rollers inside the grinding roller and reduce losses.

[0027] (2) The present invention introduces an online monitoring method for wear amount and grinding roller speed. The online wear amount detection can monitor the wear amount of the grinding roller inside the coal mill at any time without stopping the machine. When the wear amount reaches a certain level, the machine can be stopped for maintenance and replacement of parts.

[0028] (3) The optimized solution of this invention adds a switch assembly, a time relay, and an alarm. When the grinding roller seizes up, the alarm is activated only when the switch assembly closes and the time relay calculates the required closing time, thus proactively alerting the management personnel to the abnormal situation. During normal rotation of the grinding roller, the time relay is reset to zero when the switch assembly is opened, preventing it from reaching the required timing and thus avoiding the activation of the alarm.

[0029] The present invention will be explained in detail below with reference to the accompanying drawings and specific embodiments. Attached Figure Description

[0030] Figure 1 This is a schematic diagram of the structure of an online wear detection device according to Embodiment 1 of the present invention;

[0031] Figure 2 This is a schematic diagram of the meshing state between the grinding roller and the grinding bowl liner in this invention;

[0032] Figure 3 This is a schematic diagram of the structure of the present invention in Embodiment 2;

[0033] Figure 4 This is a schematic diagram of the specific structure of the switch assembly in Embodiment 2;

[0034] Figure 5 This is a circuit control diagram of some electrical components in Example 2. In the diagram, S represents a power switch.

[0035] Figure label:

[0036] 1. Cable; 2. Cable connector; 3. Nut; 4. Connecting sleeve; 5. Proximity switch; 6. Sensing block; 7. Grinding roller shaft; 8. Switch assembly; 81. Fixed block; 82. Spring; 83. Moving block; 84. Guide rod; 85. First contact; 86. Second contact; 87. Third contact; 88. Fourth contact; 9. Time relay; 10. Alarm device. Detailed Implementation

[0037] To facilitate understanding of the present invention, a more comprehensive description of the present invention will be given below with reference to the accompanying drawings, which illustrate several embodiments of the present invention. However, the present invention can be implemented in different forms and is not limited to the embodiments described in the text. Rather, these embodiments are provided to make the disclosure of the present invention more thorough and complete.

[0038] Example 1: Please refer to the appendix for details. Figure 1An online wear detection device includes a cable 1, a cable connector 2, a nut 3, a connecting sleeve 4, a proximity switch 5, and sensing blocks 6. One end of the cable 1 is connected to the proximity switch 5, and the other end is connected to the user's control system to transmit the signal from the proximity switch 5. The cable connector 2 is fitted onto one end of the connecting sleeve 4 to protect the cable 1 from wear. The connecting sleeve 4 is fitted onto the grinding roller shaft 7 and locked with the nut 3, and the connecting sleeve 4 does not move with the rotation of the grinding roller. 80% of the length of the proximity switch 5 is fitted into the connecting sleeve 4, and the sensing end of the proximity switch 5 is exposed outside the connecting sleeve 4. Several sensing blocks 6 (denoted as a) are arranged in a circle at equal intervals on the rotating part of the grinding roller and rotate with the grinding roller. The distance between the sensing blocks 6 and the proximity switch 5 and the axis of the grinding roller shaft 7 is equal, and the end face of the sensing block 6 facing the proximity switch 5 is 3-5 mm away from the sensing end of the proximity switch 5.

[0039] Specific monitoring principle:

[0040] 1. Principle of Online Monitoring of Grinding Roller Speed

[0041] During the rotation of the grinding roller, proximity switch 5 sends a signal to the user's control system every time it encounters a sensing block 6. For each revolution of the grinding roller, proximity switch 5 encounters *a* sensing blocks 6 and sends *a* signals to the control system. If the control system receives *b* signals within one minute, the detected grinding roller speed *n0* is *b* / *a* (r / min). This calculation result is directly displayed on the user's screen. The user can monitor the speed value to determine whether the operation of the coal mill is normal. If the grinding roller speed *n0* is 0, it indicates that the grinding roller has seized and immediate shutdown and maintenance are required.

[0042] n0 = b / a (1)

[0043] Where: n0: grinding roller speed (r / min);

[0044] b: Total number of received signals;

[0045] a: Number of sensor blocks in one ring.

[0046] 2. Principle of Online Monitoring of Wear of Grinding Rollers and Grinding Cup Liners

[0047] Combined with appendix Figure 2 For a given coal mill, the circumferential diameter D of the meshing point between the grinding bowl liner and the grinding roller, and the grinding bowl's rotational speed N, are constant values. The grinding bowl drives the grinding roller to rotate, and their circumferential travel at the meshing point is equal. That is:

[0048] π*D*N=π*d*n

[0049] Then d = D * N / n

[0050] Where: D: Diameter of the engagement point (mm);

[0051] N: Grinding speed (r / min);

[0052] d: Grinding roller diameter (mm);

[0053] n: Grinding roller speed (r / min).

[0054] At the start of the wear measurement recording cycle, the rotational speed is n1 and the diameter is d1; at the end of the wear measurement recording cycle, the rotational speed changes to n2 and the diameter changes to d2. Therefore, the wear amount x on one side is:

[0055] x=(d1-d2) / 2=D*N / n1-D*N / n2=D*N*(1 / n1-1 / n2) (2)

[0056] Where: x: wear amount on one side of the grinding roller (mm);

[0057] d1: Grinding roller diameter (mm) at the start of the wear recording cycle;

[0058] d 2： The diameter of the grinding roller (mm) at the end of the wear recording cycle;

[0059] n1: Grinding roller speed (r / min) at the start of the wear recording period;

[0060] n2: Grinding roller speed (r / min) at the end of the wear recording cycle.

[0061] As can be seen from the aforementioned principle of online monitoring of grinding roller speed, the grinding roller speed n can be monitored online, and therefore the wear of the grinding roller at any time period can also be monitored online.

[0062] In summary, by incorporating the above formulas (1) and (2) into the user's control system, the grinding roller speed and the amount of grinding roller wear can be displayed intuitively on the user's computer screen, thus achieving the purpose of online monitoring.

[0063] Example 2: The difference between this example and Example 1 is that:

[0064] An online wear detection device; please refer to the attached document for details. Figure 3 -Appendix Figure 4It also includes a switch assembly 8, a time relay 9, and an alarm 10. The switch assembly 8 includes a fixed block 81 fixedly connected to the grinding roller shaft 7 and a movable block 83 connected to the fixed block 81 via a spring 82. A guide rod 84 is fixed on the fixed block 81 and inserted into the movable block 83. The spring 82 is sleeved on the guide rod 84 to limit and guide the movement of the movable block 83. The part of the movable block 83 that contacts the sensing block 6 is designed as an inclined surface so that the contact of the sensing block 6 can smoothly drive the movable block 83 to move. The switch assembly 8 further includes a first contact 85 and a second contact 86 constituting the first switch A, and a third contact 87 and a fourth contact 88 constituting the second switch B. The first contact 85 and the third contact 87 are respectively fixedly connected to the fixed block 81, and the second contact 86 and the fourth contact 88 are respectively fixedly connected to the moving block 83. The first contact 85 and the second contact 86 are respectively located on the opposite sides of the fixed block 81 and the moving block 83, and the fourth contact 88 is located on the side of the third contact 87 that is away from the moving block 83. In the initial state, the spring 82 pushes the moving block 83 to contact the grinding roller, the moving block 83 moves away from the fixed block 81, the second contact 86 moves away from the first contact 85, that is, the first switch A is open, and the fourth contact 88 contacts the third contact 87, that is, the second switch B is closed; when the sensing block 6 rotates to contact the moving block 83, the moving block 83 will move towards the side where the fixed block 81 is located, so that the second contact 86 contacts the first contact 85, that is, the first switch A is closed, and the fourth contact 88 moves away from the third contact 87, that is, the second switch B is open.

[0065] like Figure 5 As shown, the first switch A and the second switch B are connected in parallel, and are connected to the time relay 9 ( Figure 5 The coil of the time relay 9 (represented by KT) is connected in series. The timing time of the time relay 9 is longer than the brief closing time of the second switch B during the normal rotation of the grinding roller. The action switch of the time relay 9 is connected to the alarm 10 ( Figure 5 (represented by W in the text) are connected in series, and the warning device 10 is an indicator light and / or an alarm.

[0066] In application, during the normal rotation of the grinding roller, the elastic reset action of the equally spaced sensing blocks 6 and springs 82 causes the moving block 83 to alternately and intermittently move towards and away from the fixed block 81 to contact the grinding roller. This causes the first switch A and the second switch B to close intermittently. The closing time of the first switch A and the second switch B does not meet the timing requirement of the time relay 9, and the time relay 9 is reset to zero each time the first switch A and the second switch B close and open. Therefore, the time relay 9 cannot activate the action switch to close during the normal rotation of the grinding roller. When the grinding roller seizes up, because the switching time between the two states of the moving block 83 contacting the sensing block 6 and the end face of the grinding roller is very short, the moving block 83 will basically remain in stable contact with the surface of the grinding roller or the sensing block 6, so that one of the first switch A and the second switch B is in the closed state. The time relay 9 starts timing. When the time relay 9 reaches the time requirement (e.g., 5-10 seconds), it will activate the action switch to close, thereby activating the alarm 10, which can more promptly remind the management and operation personnel.

[0067] Everything else is the same as in Example 1.

[0068] The present invention has been described above by way of example in conjunction with the accompanying drawings. Obviously, the specific implementation of the present invention is not limited to the above-described manner. Any non-substantial improvement made by adopting the inventive concept and technical solution of the present invention, or the direct application of the inventive concept and technical solution of the present invention to other occasions without modification, shall be within the protection scope of the present invention.

Claims

1. A method for online wear detection, characterized in that: Includes the following steps: S1. Assemble an online wear detection device, including a sensing blocks (6) arranged at equal intervals in a circle on the rotating part of the grinding roller, and a proximity switch (5) installed on the grinding roller shaft (7) for being triggered by the sensing blocks (6); S2. During the rotation of the grinding roller, the sensing block (6) rotates accordingly. For every rotation of the grinding roller, the proximity switch (5) encounters a sensing blocks (6), and the proximity switch (5) sends a signal to the control system. The control system counts the number of signals received within one minute as b. S3. The control system calculates the grinding roller speed n0 according to formula (1) and displays the result directly on the user's display screen. n0 = b / a (1) S4. Users can judge whether the operation of the coal mill is normal by monitoring the rotation speed. Once the rotation speed n0 of the grinding roller is 0, it means that the grinding roller has seized up and the machine needs to be stopped immediately for maintenance. S5. Based on steps S1-S3, the control system records the grinding roller speed n1 at the beginning of the set cycle and the grinding roller speed n2 at the end of the cycle. S6. The control system calculates the wear amount x on one side of the grinding roller according to formula (2) and displays the calculation result directly on the user's display screen. x=D*N*(1 / n1-1 / n2) (2) Where D represents the diameter of the meshing point; N represents the grinding speed; S7. Users can judge the wear condition of the grinding roller by monitoring the wear on one side of the grinding roller. When the wear reaches the level that affects the normal operation of the grinding roller, the machine should be stopped for inspection and replacement of parts.

2. The online wear detection method according to claim 1, characterized in that: In step S1, a switch assembly (8) is also installed on the grinding roller shaft (7) and electrically connected to the time relay (9) and the alarm (10). The switch assembly (8) includes a first switch and a second switch. The first switch and the second switch are connected in parallel and connected in series with the coil of the time relay (9). The action switch of the time relay (9) is connected in series with the alarm (10). In step S2, during the normal rotation of the grinding roller, the first switch and the second switch are intermittently closed. The closing time of the first switch and the second switch does not meet the timing requirement of the time relay (9), so the time relay (9) cannot activate the action switch to close, and thus the alarm (10) will not be activated. When a seizure occurs, one of the first switch and the second switch is in the closed state, and the time relay (9) starts timing. When the time relay (9) reaches the time requirement, it will activate the action switch to close, thereby activating the alarm (10) to remind the management and operators more promptly.

3. An online wear detection device, applied to the online wear detection method according to any one of claims 1-2, characterized in that: It includes several sensing blocks (6) arranged in a circle at equal intervals on the rotating part of the grinding roller and a proximity switch (5) mounted on the grinding roller shaft (7). The distance between the sensing blocks (6) and the proximity switch (5) and the axis of the grinding roller shaft (7) is equal. One end of the proximity switch (5) facing away from the sensing end is connected to a cable (1), and the other end of the cable (1) is connected to the user's control system to transmit the signal of the proximity switch (5).

4. The online wear detection device according to claim 3, characterized in that: The end face of the sensing block (6) facing the proximity switch (5) is 3-5mm away from the sensing end of the proximity switch (5).

5. The online wear detection device according to claim 3, characterized in that: The cable (1) is connected to the proximity switch (5) through the cable connector (2). The proximity switch (5) is fitted with a connecting sleeve (4) on the outside. The cable connector (2) is closed at one end of the connecting sleeve (4). The connecting sleeve (4) is closed on the grinding roller shaft (7) and locked with a nut (3). The sensing end of the proximity switch (5) is exposed outside the connecting sleeve (4).

6. The online wear detection device according to claim 3, characterized in that: It also includes a switch assembly (8), a time relay (9), and an alarm (10). The switch assembly (8) includes a fixed block (81) fixedly connected to the grinding roller shaft (7) and a movable block (83) connected to the fixed block (81) by a spring (82). The portion of the movable block (83) that contacts the sensing block (6) is set as an inclined surface. The switch assembly (8) also includes a first contact (85) and a second contact (86) constituting the first switch, and a third contact (87) and a fourth contact (88) constituting the second switch. The first contact (85) The first contact (85) and the second contact (86) are fixedly connected to the fixed block (81), the second contact (86) and the fourth contact (88) are fixedly connected to the moving block (83), and the first contact (85) and the second contact (86) are located on opposite sides of the fixed block (81) and the moving block (83), respectively. The fourth contact (88) is located on the side of the third contact (87) facing away from the moving block (83). The first switch and the second switch are connected in parallel and connected in series with the coil of the time relay (9). The action switch of the time relay (9) is connected in series with the alarm (10).

7. The online wear detection device according to claim 6, characterized in that: A guide rod (84) is fixed on the fixed block (81) and inserted into the moving block (83), and the spring (82) is sleeved on the guide rod (84).

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