Stop monitoring equipment for slow-rotation equipment

Abstract

The utility model relates to the field of thermal power generating unit operation monitoring equipment, and designs shutdown monitoring equipment for slow rotation equipment, which realizes direct and efficient monitoring of the rotation state of equipment blades by integrating proximity switch technology and a distributed control system (DCS). The proximity switch is fixed on the rack, through a non-contact monitoring mode, mechanical abrasion is remarkably reduced, the service life is prolonged, and meanwhile, the directness and reliability of monitoring signals are improved by directly connecting the proximity switch with the DCS. A rising edge delay output module and a falling edge delay output module are embedded in the DCS, are electrically connected with the proximity switch and alternately output signals to ensure that the switching value output card continuously indicates normal operation of equipment, in addition, the early warning card is activated through a logic NOR gate, fault signals are sent, immediate early warning of problems is achieved, and the safety of the equipment is guaranteed. And the pertinence and timeliness of monitoring are enhanced.

Description

Technical Field

[0001] The utility model relates to the field of thermal power unit operation monitoring equipment, in particular to a shutdown monitoring equipment for slow-rotating equipment. Background Art

[0002] In some thermal power units in the current domestic thermal power industry, the operation monitoring of the two three-compartment rotary air preheaters A and B on the boiler side is achieved through an integrated fire and rotor stall alarm detection system. The system relies on four low-speed probes and a matching speed monitor to ensure real-time monitoring of the air preheater's operating status. The speed monitor is powered by 220VAC. The internal delay determines whether the air preheater rotor is stalled by setting the number of probe detection pulses per minute and the preset value. The stall signal is sent to the DCS system in a dry contact manner for sound and light alarm. This monitoring solution directly installs the low-speed sensor on the rotating blade cover of the air preheater reducer, and uses the pulse signal generated when the blade rotates to determine whether the air preheater rotor is operating normally. Each air preheater is monitored by two independent monitoring devices to ensure the reliability and accuracy of the monitoring results. The monitor determines whether there is a stall by comparing the actual number of detected pulses with the preset value, and sends alarm information to the distributed control system through a dry contact signal to achieve rapid response. However, the existing monitoring system has several problems, mainly manifested in the following aspects: First, when the monitor itself fails, it fails to send a "sensor failure" signal to the DCS system in time, causing the alarm mechanism to fail and possibly missing a timely response to the air preheater shutdown, increasing the operational risk; Second, the low-speed probe used in conjunction with the system has been severely worn on the detection surface due to long-term exposure to the harsh environment of high temperature and high-speed rotation. In addition, it is difficult to purchase replacement probes that match the existing monitor on the market, which not only affects the accuracy of monitoring, but also brings serious challenges to equipment maintenance. Utility Model Content

[0003] In view of the above problems, there is an urgent need for a monitoring solution that is more reliable, easy to maintain and compatible with existing systems.

[0004] The utility model aims to provide a shutdown monitoring device for slow-rotating equipment, so as to overcome the problems of high failure rate of monitoring instruments, probe wear and difficulty in finding accessories in the prior art, and to achieve more efficient and stable air preheater rotor shutdown monitoring, thereby improving the overall operating safety and maintenance convenience of thermal power units.

[0005] To achieve the above-mentioned purpose, the utility model adopts the following technical scheme: a shutdown monitoring device for slow-rotating equipment, including a proximity switch and a distributed control system, the slow-rotating equipment includes a frame and a rotating part, blades are fixed on the rotating part, the proximity switch is fixed on the frame and can detect the rotation of the blades, the distributed control system includes a switch input card component and a switch output card component, the switch input card component includes a rising edge delay output module and a falling edge delay output module, the rising edge delay output module and the falling delay output module are both electrically connected to the proximity switch, the switch output card component includes a logic OR gate and a logic NOR gate, the switch output card component is electrically connected to the rising edge delay output module and the falling delay output module through the logic OR gate, and the logic NOR gate is connected to a warning card component.

[0006] The beneficial effects of this scheme are as follows: 1. The original solid-state relay and switching power supply are eliminated, making the air preheater rotor monitoring signal more direct and reliable; 2. The original detection probe is replaced by the proximity switch, and there is no friction between the proximity switch and the monitored slow-rotating equipment, which can be used for a longer time; 3. The DCS system is embedded with switch input cards and switch output cards, in which the switch input card is equipped with a rising edge delay output module and a falling edge delay output module. These two modules form an electrical connection with the proximity switch to accurately capture every subtle change in the movement of the blade, that is, the moment when the blade approaches or moves away from the proximity switch, respectively generates and maintains a single pulse signal of a program cycle. The two modules alternately output signals to ensure that the switch output card continues to indicate the normal operation of the equipment. Once the blade rotates abnormally, the pulse signal sequence is interrupted, and the switch output card will show intermittent signal flashing, which directly reflects the problem. At the same time, through the series connection of the logic OR gate and the logic OR gate, the switch output card only activates the warning card through the logic OR gate when the abnormality is detected, and sends a fault signal, realizing the immediate warning of the problem and enhancing the pertinence and timeliness of monitoring.

[0007] Furthermore, the distributed control system also includes a power supply, which is electrically connected to the switch input card and provides energy for the switch input card. The proximity switch is inductive, and the power supply required by the proximity switch is the same as that of the switch input card and is powered by the power supply.

[0008] Furthermore, the proximity switch and the switch input card are both powered by 48VDC.

[0009] Beneficial effects: The proximity switch can be powered directly through the power supply of the distributed control system. The proximity switch can be powered directly through the input channel of the distributed control system, reducing the wiring work required for additional functions, simplifying the installation process of the monitoring equipment, and is safer than the original monitor's 220V AC power.

[0010] Furthermore, two groups of proximity switches are provided, and the two groups of proximity switches are respectively connected to switch quantity input card components.

[0011] Beneficial effect: The two sets of data are calibrated against each other, making monitoring more reliable.

[0012] Furthermore, the early warning card comprises a light-emitting sign and a sound alarm, and both the light-emitting sign and the sound alarm are electrically connected to the logic NOR gate.

[0013] Beneficial effect: The combination of display alarm and sound alarm improves the timeliness of early warning detection.

[0014] Furthermore, a delay relay is connected between the sound and the NOR gate, and the delay time set by the delay relay is 15s.

[0015] Beneficial effect: By setting the delay relay, the sound will be started 15 seconds after the light-emitting sign is started, thereby reducing the possibility of false alarms.

[0016] Furthermore, the rising edge delay output module includes a first delay module, and a single start program cycle of the first delay module is the same as the time it takes for the blade to pass through the proximity switch. The falling edge delay output module includes a second delay module, and a gap is provided between the blades. The single start program cycle of the second delay module is the same as the time it takes for the gap to pass through the proximity switch.

[0017] Beneficial effect: By setting the single start program cycle in the first delay module and the second delay module, the single start program cycle is adapted to the blade speed, thereby utilizing the alternating start of the rising edge delay output module and the falling edge delay output module to continuously maintain the generation of the pulse signal and avoid signal advance and delay. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 This is a logic circuit diagram of Embodiment 1 of the utility model;

[0019] Figure 2 This is the logic circuit diagram of Example 2 of the utility model. DETAILED DESCRIPTION

[0020] The following is further described in detail through specific implementation methods:

[0021] The figure marks in the drawings of the specification include: proximity switch 1, switch input card 21, rising edge delay output module 211, falling edge delay output module 212, switch output card 22, logic OR gate 221, logic NOR gate 222, warning card 23, delay relay 231.

[0022] Example 1

[0023] Embodiment 1 is basically as attached Figure 1 As shown, the slow-rotating equipment monitored by the outage monitoring device of this embodiment includes a frame and a rotating member, and blades are fixed on the rotating member, such as Figure 1 The shutdown monitoring device of a slow-rotating equipment shown in the figure monitors the operation of the two three-compartment rotary air preheaters A and B on the boiler side to ensure the normal operation of at least one air preheater, including a proximity switch 1 and a distributed control system. The proximity switch 1 can be purchased as a common 48V DC inductive proximity switch 1 on the market. The proximity switch 1 is fixed on the frame and can detect the rotation of the blades. To avoid damage to the proximity switch 1, each rotating part is provided with two groups of proximity switches 1.

[0024] The distributed control system includes a power supply, an early warning card 23, a switch output card 22 and a switch input card 21. The power supply includes a 48V DC current output terminal. The early warning card 23 includes a light-emitting sign and a speaker. The switch output card 22 includes a logic OR gate 221 and a logic NOR gate 222 that are interconnected. The logic OR gate 221 is also called an OR circuit. If several conditions are met, an event will occur. This relationship is called an "OR" logic relationship. A circuit with an "OR" logic relationship is called an OR gate. The OR gate has multiple input terminals and one output terminal. As long as one of the inputs is at a high level (logic "1"), the output is at a high level (logic "1"). Only when all the inputs are at a low level (logic "0"), the output is at a low level (logic "0"). The logic NOR gate 222 is similar to the logic OR gate 221, except that the output of the logic NOR gate 222 is low level (logic "0") as long as one of the inputs is high level (logic "1"); the output is high level (logic "1") only when all the inputs are low level (logic "0"). The light-emitting sign and the audio are both electrically connected to the logic NOR gate 222, and a delay relay 231 is connected between the audio and the logic NOR gate 222. After the delay relay 231 inputs a high level signal, it delays the output of the high level signal. In this solution, the delay time of the delay relay 231 is 15s, that is, the audio is activated 15s after the logic NOR gate 222 outputs a signal to light up the light-emitting sign.

[0025] The energy required by the switch input card 21 is 48V DC. Figure 1As shown, the switch input card 21 includes a rising edge delay output module 211 and a falling edge delay output module 212. The rising edge delay output module 211 will trigger a single pulse output when a rising edge is detected in the input IN, which lasts for a program cycle; the falling edge delay output module 212 will trigger a single pulse output when a falling edge is detected in the input IN, which lasts for 1 program cycle. The rising edge delay output module 211 and the falling edge delay output module 212 are both electrically connected to the 48V DC current output terminal. The rising edge delay output module 211 and the falling edge delay output module 212 are both electrically connected to the proximity switch 1. The rising edge delay output module 211 includes a first delay module, and the single start program cycle of the first delay module is the same as the time for the blade to pass through the proximity switch 1. The falling edge delay output module 212 includes a second delay module, and a gap is set between the blades. The single start program cycle of the second delay module is the same as the time for the gap to pass through the proximity switch 1.

[0026] Example 2

[0027] Embodiment 2 is substantially the same as Embodiment 1, as shown in Figure 2 As shown, the difference is that the switch output card 22 includes two logic OR gates 222, and the two logic OR gates 222 are respectively connected to the early warning card 23. When it is necessary to monitor the stall of the two Howden Hua three-compartment rotary air preheaters A and B respectively, the signal input by the switch input card 21 can be diverted and output through the two logic OR gates 222, so as to monitor the operation of the two Howden Hua three-compartment rotary air preheaters A and B respectively. At the same time, the rotor stall alarm configuration circuits of the A and B air preheaters are separated, so as to avoid the alarm channel being occupied when a single air preheater is running and losing the rotor stall alarm function of the running air preheater.

[0028] The above is only an embodiment of the utility model, and the common knowledge such as the known specific technical solutions and / or characteristics in the solution is not described in detail here. It should be pointed out that the technical means for solving the problems in the above-mentioned embodiments of the utility model can be used in combination to solve multiple technical problems at the same time. For those skilled in the art, several deformations and improvements can be made without departing from the technical solution of the utility model, which should also be regarded as the protection scope of the utility model, and these will not affect the effect of the implementation of the utility model and the practicality of the patent. The scope of protection required by this application shall be based on the content of its claims, and the specific implementation methods and other records in the specification can be used to interpret the content of the claims.

Claims

1. A shutdown monitoring device for slow-rotating equipment, characterized in that: It includes a proximity switch and a distributed control system. The slow-rotating device includes a frame and a rotating part. Blades are fixed on the rotating part. The proximity switch is fixed on the frame and can detect the rotation of the blades. The distributed control system includes a switch input card and a switch output card. The switch input card includes a rising edge delay output module and a falling edge delay output module. The rising edge delay output module and the falling edge delay output module are both electrically connected to the proximity switch. The switch output card includes a logic OR gate and a logic NOR gate. The switch output card is electrically connected to the rising edge delay output module and the falling edge delay output module through the logic OR gate. The logic NOR gate is connected to an early warning card.

2. The outage monitoring device for slow-rotating equipment according to claim 1, characterized in that: The distributed control system also includes a power supply, which is electrically connected to the switch input card and provides energy for the switch input card. The proximity switch is inductive, and the power supply required by the proximity switch is the same as that of the switch input card and is powered by the power supply.

3. The outage monitoring device for slow-rotating equipment according to claim 2, characterized in that: The energy required by the proximity switch and the switch input card is 48V DC.

4. The outage monitoring device for slow-rotating equipment according to claim 3, characterized in that: Two groups of proximity switches are provided, and the two groups of proximity switches are respectively connected with switch quantity input card components.

5. The outage monitoring device for slow-rotating equipment according to claim 4, characterized in that: The early warning card comprises a light-emitting sign and a sound, and both the light-emitting sign and the sound are electrically connected to a logic NOR gate.

6. The outage monitoring device for slow-rotating equipment according to claim 5, characterized in that: A delay relay is connected between the sound and the NOR gate, and the delay time set by the delay relay is 15s.

7. The outage monitoring device for slow-rotating equipment according to claim 1, characterized in that: The rising edge delay output module includes a first delay module, and a single start program cycle of the first delay module is the same as the time it takes for the blade to pass through the proximity switch. The falling edge delay output module includes a second delay module, and a gap is set between the blades. The single start program cycle of the second delay module is the same as the time it takes for the gap to pass through the proximity switch.

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